Patent Publication Number: US-2016228276-A1

Title: Anchors and methods for intestinal bypass sleeves

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. Non-Provisional application Ser. No. 13/360,689 filed Jan. 28, 2013 which claims benefit under 35 U.S.C. section 119(e) of U.S. provisional patent application 61/462,156, filed Jan. 28, 2011, and U.S. provisional patent application 61/519,507, filed May 24, 2011, both of which are herein incorporated by reference in their entirety. U.S. Non-Provisional application Ser. No. 13/360,689 filed Jan. 28, 2013 is a continuation-in-part of each of the following applications, each of which are herein incorporated by reference in their entirety: (1) U.S. patent application Ser. No. 12/752,697, filed Apr. 1, 2010, which claims the benefit of U.S. provisional patent application 61/211,853, filed Apr. 3, 2009; (2) U.S. patent application Ser. No. 12/833,605, filed Jul. 9, 2010, which claims the benefit of U.S. provisional patent application 61/270,588, filed Jul. 10, 2009; (3) U.S. patent application Ser. No. 12/986,268, filed Jan. 7, 2011, which claims the benefit of U.S. provisional patent application 61/335,472, filed Jan. 7, 2010; and (4) U.S. patent application Ser. No. 13/298,867, filed Nov. 17, 2011, which claims the benefit of U.S. provisional patent application 61/458,060, filed Nov. 17, 2010. 
    
    
     TECHNICAL FIELD 
     This invention generally relates to implants placed within gastrointestinal systems, including the esophagus, the stomach and the intestines. In particular it relates to implant systems having components implantable and removable using endoscopic techniques for treatment of obesity, diabetes, reflux, gastroparesis and other gastrointestinal conditions. 
     BACKGROUND 
     Bariatric surgery procedures, such a sleeve gastrectomy, the Rouen-Y gastric bypass (RYGB) and the bileo-pancreatic diversion (BPD), modify food intake and/or absorption within the gastrointestinal system to effect weight loss in obese patients. These procedures affect metabolic processes within the gastrointestinal system, by either short circuiting certain natural pathways or creating different interaction between the consumed food, the digestive tract, its secretions and the neuro-hormonal system regulating food intake and metabolism. In the last few years there has been a growing clinical consensus that obese patients who undergo bariatric surgery see a remarkable resolution of their type-2 Diabetes Mellitus (T2DM) soon after the procedure. The remarkable resolution of diabetes after RYGB and BPD typically occurs too fast to be accounted for by weight loss alone, suggesting there may be a direct impact on glucose homeostasis. The mechanism of this resolution of T2DM is not well understood, and it is quite likely that multiple mechanisms are involved. 
     One of the drawbacks of bariatric surgical procedures is that they require fairly invasive surgery with potentially serious complications and long patient recovery periods. In recent years, there is an increasing amount of ongoing effort to develop minimally invasive procedures to mimic the effects of bariatric surgery using minimally invasive procedures. One such procedure involves the use of gastrointestinal implants that modify transport and absorption of food and organ secretions. For example, U.S. Pat. No. 7,476,256 describes an implant having a tubular sleeve with anchoring barbs, which offer the physician limited flexibility and are not readily removable or replaceable. Moreover, stents with active fixation means, such as barbs that deeply penetrate into surrounding tissue, may potentially cause tissue necrosis and erosion of the implants through the tissue, which can lead to complications, such as bacterial infection of the mucosal tissue or systemic infection. Also, due to the intermittent peristaltic motion within the digestive tract, implants such as stents have a tendency to migrate. 
     Gastroparesis is a chronic, symptomatic disorder of the stomach that is characterized by delayed gastric emptying in the absence of mechanical obstruction. The cause of gastroparesis is unknown, but it may be caused by a disruption of nerve signals to the intestine. The three most common etiologies are diabetes mellitus, idiopathic, and postsurgical. Other causes include medication, Parkinson&#39;s disease, collagen vascular disorders, thyroid dysfunction, liver disease, chronic renal insufficiency, and intestinal pseudo-obstruction. The prevalence of diabetic gastroparesis (DGP) appears to be higher in women than in men, for unknown reasons. 
     Diabetic gastroparesis affects about 40% of patients with type 1 diabetes and up to 30% of patients with type 2 diabetes and especially impacts those with long-standing disease. Both symptomatic and asymptomatic DGP seem to be associated with poor glycemic control by causing a mismatch between the action of insulin (or an oral hypo-glycemic drug) and the absorption of nutrients. Treatment of gastroparesis depends on the severity of the symptoms. 
     SUMMARY 
     According to various embodiments, the present invention provides for an apparatus and method to place and anchor an intestinal bypass sleeve within the pyloric antrum, pylorus, duodenum and jejunum. The gastrointestinal implant herein disclosed can be inserted endoscopically (when the device is loaded into a delivery catheter) through the mouth, throat, stomach and intestines. The gastrointestinal implant device includes a flexible thin-walled sleeve and an expandable anchor attached to the proximal end of the sleeve; secondary anchors may also anchor other portions of the thin-walled sleeve. 
     The present invention herein disclosed (with a short bypass sleeve or no bypass sleeve) can also be used to hold open the pylorus and may help to reduce the symptoms of gastroparesis, by allowing the stomach contents to exit the stomach easier through the pylorus into the duodenum. An active pumping means may also be attached to the expandable anchor to actively pump the stomach contents from the pyloric antrum into the duodenum. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-sectional view of a portion of the digestive tract in a human body with an intestinal bypass sleeve implanted in the duodenum from the pylorus to the ligament of treitz. The sleeve is held in place at the pylorus by an expandable anchor that anchors on the pylorus. 
         FIG. 2  is a cross-sectional view of a portion of the digestive tract in a human body with an endoscope inserted through the mouth, esophagus and stomach to the pylorus. 
         FIG. 3A  is a drawing of an over-the-wire sizing balloon that may be used to dilate and measure (size) the intestinal tract and pylorus anatomy. 
         FIG. 3B  is a drawing of a rapid exchange or monorail sizing balloon that may be used to dilate and measure (size) the intestinal tract and pylorus anatomy. 
         FIG. 4  is a cross-sectional view of a portion of the digestive tract in a human body. An endoscope is inserted through the mouth, esophagus and stomach to the pylorus. An over-the-wire sizing balloon is inserted through the working channel of the endoscope over a guidewire and is advanced across the pyloric opening. The balloon is inflated with saline or contrast media to a low pressure to open the pylorus and duodenum and allow measurement of the lumen diameter of the pyloric antrum, pylorus and duodenal bulb. 
         FIG. 5  is a cross-sectional drawing of the pyloric antrum, pylorus, duodenal bulb and duodenum. An expandable anchor and intestinal bypass sleeve is implanted into the pylorus. 
         FIG. 6  is a drawing of an expandable anchor according to exemplary embodiments of the invention. 
         FIG. 7  is a drawing of a flat representation of the circumference of the expandable anchor disclosed in  FIG. 2 . The anchor can be laser cut from round tubing or a flat sheet of Nitinol. 
         FIG. 8  is a drawing of a flat representation of the circumference of the expandable anchor disclosed in  FIG. 2 . The expandable anchor can be laser cut from round tubing or flat sheet of Nitinol. The individual spring arm elements of the anchor are cut at a bias angle to the longitudinal axis. 
         FIG. 9  is a drawing of exemplary heat set mandrels for forming the shape of the anchor from the laser cut shape of  FIG. 7  and  FIG. 8  to the final shape of the anchor in  FIG. 4 . 
         FIG. 10  is a sectional view of a delivery catheter for the expandable anchor and intestinal bypass sleeve implanted. 
         FIG. 11  is a sectional view of an anchor and sleeve implanted into a pylorus and duodenal bulb and duodenum. The expandable anchor is covered with a membrane on both the inside and outside surfaces of the anchor to close the openings in between the spring arm elements. An intestinal bypass sleeve is attached to the expandable anchor. 
         FIG. 12  is a sectional view of a recovery catheter for removing the expandable anchor and intestinal bypass sleeve from the human gastrointestinal tract. 
         FIG. 13  is a sectional view of the expandable anchor in the collapsed state with the outer sheath of the recovery catheter covering and constraining the expandable anchor. 
         FIG. 14  is a sectional view of an alternative embodiment of an anchor and sleeve implanted into the pylorus and duodenal bulb and duodenum. 
         FIG. 15  is a sectional view of an alternative embodiment of an anchor and sleeve implanted into the pylorus and duodenal bulb and duodenum. 
         FIG. 16  is a sectional view of an alternative embodiment of the invention herein disclosed implanted into the pylorus and duodenal bulb and duodenum. The through lumen of the expandable anchor contains a duck bill type anti-reflux valve and a flow limiter. 
         FIG. 17  is a sectional view of an alternative embodiment of the invention herein disclosed implanted into the pylorus and duodenal bulb and duodenum. The through lumen of the expandable anchor contains a ball and cage anti-reflux valve and alternatively a bi-leaflet anti-reflux valve. 
         FIG. 18  shows an alternative embodiment of an expandable anchor. 
         FIG. 19  is a partial cross-sectional drawing of the pyloric antrum, pylorus, duodenal bulb and duodenum. An alternative embodiment of an expandable anchor intestinal bypass sleeve is implanted into the pyloric antrum, pylorus, duodenal bulb and duodenum. 
         FIG. 20  shows an alternative embodiment of an expandable anchor. 
         FIG. 21A  is a drawing of a flat representation of the expandable anchor shown in  FIG. 20 . 
         FIG. 21B  is a drawing of a cylindrical mandrel for heat setting the expandable anchor to the hourglass shape as in  FIG. 20 . 
         FIG. 22  shows an alternative embodiment of an expandable anchor. 
         FIG. 23  shows an alternative embodiment of an expandable anchor. 
         FIG. 24  is a drawing of expandable anchor of  FIG. 23  in a compressed state, with a sheath constraining it on the outside diameter. 
         FIG. 25  shows an alternative embodiment of an expandable anchor formed from wire. 
         FIG. 26  shows an alternative embodiment of an expandable anchor formed from wire. 
         FIG. 27  shows an alternative embodiment of an expandable anchor formed from wire. 
         FIG. 28  shows an alternative embodiment of an expandable anchor formed from wire. 
         FIG. 29  shows an alternative embodiment of an expandable anchor. 
         FIG. 30  shows an alternative embodiment of an expandable anchor. 
         FIG. 31  is a cross-sectional view of the pyloric antrum, pylorus, duodenal bulb and the duodenum in the human body. An expandable anchor and intestinal bypass sleeve is implanted across the pylorus. 
         FIG. 32  shows an alternative embodiment of an expandable anchor formed in the shape of a toroidal-shaped coil. 
         FIG. 33A  is a drawing of an alternative embodiment of an expandable anchor formed in the shape of a toroidal-shaped coil. The coil may have small tissue penetrating anchors on the outer surface of the coil. 
         FIG. 33B  is a drawing of an alternative embodiment of an expandable anchor formed in the shape of a toroidal-shaped coil. The direction of the winding of the coil is reversed to cancel out the helical twisting action of the spring. 
         FIG. 33C  is a drawing of an alternative embodiment of an expandable anchor formed in the shape of a toroidal-shaped coil as previously disclosed. The spring is wound to have double helices that are 180 degrees offset from each other. 
         FIG. 34A  is an alternative embodiment of a toroidal spring that is made from laser cutting a pattern into a round piece of Nitinol tubing. The Nitinol tubing is laser cut in the straight tubular shape and then the cut tube is then formed into the toroidal shape. 
         FIG. 34B  is an alternative embodiment of a toroidal spring that is made from laser cutting a pattern into a round piece of Nitinol tubing. The Nitinol tubing is laser cut in the straight round tubular shape and then it is formed into the toroidal shape. Alternatively, the part may be cut from a flat sheet of Nitinol and then shape set into the final shape. 
         FIG. 35  is a drawing of an alternative embodiment of an expandable anchor. The drawing shows additional embodiments for the expandable anchors in  FIG. 32 ,  FIG. 33  and  FIG. 34 . 
         FIG. 36  is an assembly drawing with the expandable anchors in  FIG. 32 ,  FIG. 33 ,  FIG. 34  and 
         FIG. 37  is a drawing showing an assembly drawing of a fixed diameter cylinder for the central pyloric portion of the invention herein disclosed. 
         FIG. 38  is drawing showing of a central pyloric portion of the invention herein disclosed in which the mid portion allows for opening and closing of the pylorus, while there is a first and a second ring which are fixed rigidly together. The expandable anchors in the pyloric antrum and the duodenal bulb are tethered to the first and second rings. 
         FIG. 39  is a sectional view of the invention herein disclosed implanted into the pyloric antrum, pylorus and duodenal bulb and duodenum. The anchoring device is comprised of two disk-shaped expandable anchors that are connected to a central cylinder which has a thin-walled compliant membrane over the central portion to allow opening and closing of the pyloric aperture. 
         FIG. 40  is a sectional view of the invention herein disclosed implanted into the pyloric antrum, pylorus and duodenal bulb and duodenum. The anchoring device is comprised of two disk-shaped expandable anchors that are connected to a central cylinder. The lumen of the anchoring device has a one-way anti-reflux valve and a flow limiter. 
         FIG. 41  is a sectional view of the invention herein disclosed implanted into the pyloric antrum, pylorus and duodenal bulb and duodenum. The anchoring device is comprised of two disk-shaped expandable anchors that are connected to a central cylinder. The diameter of the central cylinder is elastic and the diameter can be compressed to allow a reduced diameter of the anchor to allow the anchor to be loaded onto a smaller diameter catheter than with a fixed diameter central cylinder. 
         FIG. 42  is a sectional view of the invention herein disclosed implanted into the pyloric antrum, pylorus and duodenal bulb and duodenum. The anchoring device is comprised of two disk-shaped expandable anchors that are connected by a thin-walled tubular membrane. The thin-walled tubular membrane allows normal pylorus opening and closing. 
         FIG. 43  is a sectional view of the invention herein disclosed implanted into the duodenal bulb and duodenum. The anchoring device is comprised of two disk-shaped expandable anchors that are connected to a central cylinder. The lumen of the anchoring device has an optional one-way anti-reflux valve and an optional flow limiter. The anti-reflux valve and flow-limiter can be used together in combination or separately on the device. 
         FIG. 44  is a sectional view of the invention herein disclosed. The anchoring device is comprised of two disk-shaped expandable anchors that are connected to a central cylinder. The anchoring device is implanted into the pyloric antrum and the intestinal bypass sleeve is implanted from the pyloric antrum to the duodenum. 
         FIG. 45A  is a sectional view of the invention herein disclosed. The anchoring device is comprised of two disk-shaped expandable anchors that are connected to a central cylinder. Four additional expandable anchors are attached to the thin-walled sleeve and are implanted into the pyloric antrum. 
         FIG. 45B  is a drawing of a flat braided wire form that may be used as an expandable anchor. 
         FIG. 46  is a drawing of an alternative embodiment of the invention herein disclosed. The expandable anchor is comprised of a hollow tubular braided structure of wire. The wire form has been shaped to conform to the shape of the pylorus and the duodenal bulb. 
         FIG. 47  is a drawing of an alternative embodiment of the invention herein disclosed. The expandable anchor is comprised of hollow tubular braided structure of wire. The wire form has been shaped to conform to the shape of the pylorus and the duodenal bulb. The expandable anchor and the intestinal bypass sleeve have been implanted into a human pylorus and duodenal bulb. 
         FIG. 48  is a drawing of an alternative embodiment of the invention herein disclosed. The expandable anchor is comprised of a hollow tubular braided structure of wire. The wire form has been shaped to conform to the shape of the pylorus and the duodenal bulb. The expandable anchor has an annular groove formed in wall the duodenal bulb portion of the expandable anchor. The annular groove is sized to provide for a modular connection means between an expandable anchor and intestinal bypass sleeve. 
         FIG. 49  is a drawing of an alternative embodiment of the invention herein disclosed implanted into a pyloric antrum, pylorus, duodenal bulb, and duodenum. The expandable anchor is comprised of a hollow tubular braided structure of wire. The wire form has been shaped to conform to the shape of the pylorus and the duodenal bulb. The expandable anchor has an annular grove formed in wall the duodenal bulb portion of the expandable anchor. The annular groove is sized to provide for a modular connection means between an expandable anchor and intestinal bypass sleeve. An intestinal bypass sleeve with an expandable anchor attached to the end of the sleeve is attached to the annular groove in the anchor in the pylorus. 
         FIG. 50  is a drawing showing the process steps for the manufacturing of the expandable anchor as in  FIG. 46 ,  FIG. 47  and  FIG. 48 . 
         FIG. 51  is drawing of an alternative embodiment of the expandable anchor herein disclosed. 
         FIG. 52A  is a drawing of a pyloric antrum, pylorus, duodenal bulb and duodenum and of the expandable anchor of  FIG. 52 . 
         FIG. 52B  is a drawing of a pylorus and of the expandable anchor of  FIG. 52  implanted into it. 
         FIG. 53  is drawing of an alternative embodiment of the expandable anchor herein disclosed. 
         FIG. 54  is a drawing of an alternative embodiment of an expandable anchor that has optional barbs to provide for an additional securing means to the pylorus. 
         FIG. 55  is a sectional view of the invention herein disclosed implanted into the pyloric antrum, pylorus and duodenal bulb and duodenum. The anchoring device is comprised of two disk-shaped expandable anchors that are connected to a central cylinder. The diameter of the central cylinder is fixed, but it may also be designed to allow it to be reduced in diameter during loading of the device onto a catheter. The length of the central cylinder is adjusted to allow the spacing between the two disks to be variable in spacing. 
         FIG. 56  is a sectional view of the invention herein disclosed implanted into the pyloric antrum, pylorus and duodenal bulb and duodenum. The anchoring device is comprised of two toroidal-shaped expandable anchors that are connected to a central cylinder. The diameter of the central cylinder is fixed, but it may also be elastic to allow it to be reduced in diameter during loading of the device onto a catheter. An optional needle, suture, T-bar, hollow helical anchor or screw type anchor is inserted into and or through the tissue of the pylorus, pyloric antrum or duodenum to provide additional anchoring and securement of the intestinal bypass sleeve anchoring device to the pylorus anatomy. Additional anchoring means may include a T-Bar and suture. 
         FIG. 57  is a sectional view of the invention herein disclosed implanted into a pylorus, duodenal bulb and duodenum. An expandable ring is sized large enough in diameter to engage the wall of the stomach pyloric antrum. The central portion of the device is constructed of a ridged fixed diameter cylinder, or alternatively a compressible cylinder or a thin-walled sleeve. An optional needle, suture, T-bar, hollow helical anchor or screw-type anchor is inserted into and or through the tissue of the pylorus, pyloric antrum or duodenum to provide additional anchoring and securement of the intestinal bypass sleeve anchoring device to pylorus anatomy or other suitable location. 
         FIG. 58  is a cross-sectional view of a portion of the digestive tract in a human body. An intestinal bypass sleeve is implanted in the duodenum from the pylorus to the ligament of treitz. The sleeve is held in place at the pylorus by an expandable anchor that anchors on the pylorus optional secondary expandable anchors anchor the sleeve at additional locations in the duodenum and jejunum. An expandable anchor with an anti-reflux valve is implanted at the gastroesophageal (GE) junction to help resolve gastroesophageal reflux disease (GERD). 
         FIG. 59A  is a drawing of an alternative embodiment of an expandable anchor. 
         FIG. 59B  is a drawing of an alternative embodiment of an expandable anchor. 
         FIG. 59C  is a drawing of an alternative embodiment of an expandable anchor. 
         FIG. 60  is a drawing of  FIG. 59A  implanted into a pylorus. Alternatively  FIG. 59A ,  FIG. 59B  and  FIG. 59C  could also be implanted into the pyloric antrum, duodenal bulb or duodenum or GE junction. 
         FIG. 61A  is a drawing of an intestinal bypass sleeve. 
         FIG. 61B  is a drawing of an alternative embodiment of an intestinal bypass sleeve. 
         FIG. 62A  is a drawing of an alternative embodiment of an intestinal bypass sleeve. 
         FIG. 62B  is a drawing of an alternative embodiment of an intestinal bypass sleeve. 
         FIG. 63A  is a drawing of an alternative embodiment of an intestinal bypass sleeve. 
         FIG. 63B  is a drawing of an alternative embodiment of an intestinal bypass sleeve. 
         FIG. 64A  is drawing of a hemispherical-shaped covering for an expandable anchor that is assembled from a sheet of polymer material into a spherical shape. 
         FIG. 64B  is a drawing of hemispherical-shaped covering for an expandable anchor that is made by radial stretching a tube perform into a spherical shape by blow-molding or mechanical stretching. 
         FIG. 64C  is drawing of a hemispherical-shaped covering for an expandable anchor that is assembled from a sheet of polymer material into a tubular shape. 
         FIG. 65A  is drawing of a hemispherical- or disk-shaped covering for an expandable anchor that is assembled from sheet material into a spherical or disk shape. 
         FIG. 65B  is drawing of a disk-shaped covering for an expandable anchor that is assembled from sheet material into a disk shape. 
         FIG. 65C  is drawing of a hemispherical- or disk-shaped covering for an expandable anchor that is assembled from tube and sheet material into a disk shape. 
         FIG. 66  is a drawing of an expandable anchor that has an Archimedes screw-type pump and motor integrated into the central cylinder or thru lumen of the device. The Archimedes screw is used to control the flow rate of chyme and/or to pump chyme from the stomach into the duodenum. 
         FIG. 67  is a sectional drawing of a part of the anatomy, a pyloric antrum, pylorus, duodenal bulb, and duodenum. The expandable anchor of  FIG. 66  is implanted into the pyloric antrum, pylorus, duodenal bulb and duodenum. 
         FIG. 68  is a cross-sectional drawing of a portion of the digestive tract in a human body. The expandable anchor of  FIG. 66  is implanted into the pyloric antrum, pylorus, duodenal bulb and duodenum. A secondary Archimedes screw-type pump is attached to the first pump by means of a flexible drive shaft and is housed in a hollow flexible cannula that is attached to the expandable anchor. 
         FIG. 69A  is a drawing an alternative embodiment of an expandable anchor. 
         FIG. 69B  is a drawing of an alternative embodiment of an expandable anchor. 
         FIG. 70A  is drawing of a piece of ePTFE tubing with an inner tube of silicone or latex inserted through the inside diameter of the ePTFE. The ePTFE tube in the final form can be use for covering an expandable anchor used to anchor an intestinal bypass sleeve. The covering for the expandable anchor and the intestinal bypass sleeve can be formed into one single unitary piece in some embodiments. 
         FIG. 70B  is a longitudinal cross-section drawing of the ePTFE tube and silicone tube shown in  FIG. 70A . 
         FIG. 70C  is a drawing of a mold cavity the ePTFE tube from  FIG. 70A  and  FIG. 70B  will be radially stretched and inflated into the shape of the mold cavity. The radial expansion of the tube of ePTFE is like what was previously disclosed in  FIG. 64B . 
         FIG. 71A  is a drawing of a two mold cavities of  FIG. 70C  that are used together to provide an enclosed cavity to limit the expansion of the ePTFE during the blow-molding radial stretching process. 
         FIG. 71B  is a drawing of the two mold cavities assembled one cavity half on top of the other. The ePTFE tube and latex tubing are inserted through the central bore between the two mold halves. 
         FIG. 72A  is a drawing of the two mold halves opened after the ePTFE tube has been blow-molded to the shape of the mold cavities. 
         FIG. 72B  is a drawing of the ePTFE tube removed from the mold cavity after the blow-molding/radial stretching process is complete. 
         FIG. 72C  is a drawing of the cross-section of the ePTFE tube and silicone tube inflated, while the two tubes are still in the mold of  FIG. 71B , after the pressure is released. 
         FIG. 73  is a drawing of an alternate embodiment for a shape for the mold cavity for blow-molding the ePTFE tube. 
         FIG. 74  is a drawing of an alternate embodiment of a shape for the mold cavity for blow-molding the ePTFE tube. 
         FIG. 75  is a drawing of an alternate embodiment of a shape for the mold cavity for blow-molding the ePTFE tube. 
         FIG. 76  is a drawing of an alternate embodiment of a shape for the mold cavity for blow-molding the ePTFE tube. 
         FIG. 77A  is a drawing of the final formed shape of the ePTFE tube after blow-molding/radial stretching of the original cylindrical tube of ePTFE. 
         FIG. 77B  is a drawing of an alternative embodiment the final formed shape of the ePTFE tube after blow-molding/radial stretching of the original cylindrical tube of ePTFE. 
         FIG. 77C  is a drawing of an alternative embodiment the final formed shape of the ePTFE tube after blow-molding/radial stretching of the original cylindrical tube of ePTFE. 
         FIG. 77D  is a drawing of an alternative embodiment the final formed shape of the ePTFE tube after blow-molding/radial stretching of the original cylindrical tube of ePTFE. 
         FIG. 77E  is a drawing of an alternative embodiment the final formed shape of the ePTFE tube after blow-molding/radial stretching of the original cylindrical tube of ePTFE. 
         FIG. 78A  is a drawing of the final formed shape of the ePTFE tube after blow-molding/radial stretching of the original cylindrical tube of ePTFE. The anchor covering portion of the sleeve and the intestinal bypass sleeve are formed integrally into one sleeve. 
         FIG. 78B  is a drawing of the final formed shape of the ePTFE tube after blow-molding/radial stretching of the original cylindrical tube of ePTFE. The anchor covering portion of the sleeve and the intestinal bypass sleeve are formed integrally into one sleeve. The small-diameter end of the tube is started to be inverted inside to pull it inside to form an interior tube layer for the expandable anchor. 
         FIG. 78C  is a drawing of the final formed shape of the ePTFE tube after blow-molding/radial stretching of the original cylindrical tube of ePTFE. The anchor covering portion of the sleeve and the intestinal bypass sleeve are formed integrally into one sleeve. The small-diameter end of the tube is fully inverted inside forming an interior layer for the expandable anchor. 
         FIG. 79A  is a drawing of an alternative embodiment of the final formed shape of the ePTFE tube after blow-molding/radial stretching of the original cylindrical tube of ePTFE. The anchor covering portion of the sleeve and the intestinal bypass sleeve are formed integrally into one sleeve. 
         FIG. 79B  is a drawing of an alternative embodiment of the final formed shape of the ePTFE tube after blow-molding/radial stretching of the original cylindrical tube of ePTFE. The anchor covering portion of the sleeve and the intestinal bypass sleeve are formed integrally into one sleeve. The small diameter end of the tube is started to be inverted inside to pull it inside to form an interior tube layer for the expandable anchor. 
         FIG. 79C  is a drawing of an alternative embodiment of the final formed shape of the ePTFE tube after blow-molding/radial stretching of the original cylindrical tube of ePTFE. The anchor covering portion of the sleeve and the intestinal bypass sleeve are formed integrally into one sleeve. The small diameter end of the tube is fully inverted inside forming an interior layer for the expandable anchor. 
         FIG. 80A  is a drawing of an alternative embodiment of the final formed shape of the ePTFE tube after blow-molding/radial stretching of the original cylindrical tube of ePTFE. The anchor covering portion of the sleeve and the intestinal bypass sleeve are formed integrally into one sleeve. 
         FIG. 80B  is a drawing of an alternative embodiment of the final formed shape of the ePTFE tube after blow-molding/radial stretching of the original cylindrical tube of ePTFE. The anchor covering portion of the sleeve and the intestinal bypass sleeve are formed integrally into one sleeve. The small-diameter end of the tube is started to be inverted inside to pull it inside to form an interior tube layer for the expandable anchor. 
         FIG. 81A  is a drawing of an alternative embodiment of the final formed shape of the ePTFE tube after blow-molding/radial stretching of the original cylindrical tube of ePTFE. The anchor covering portion of the sleeve and the intestinal bypass sleeve are formed integrally into one sleeve. 
         FIG. 81B  is a drawing of an alternative embodiment of the final formed shape of the ePTFE tube after blow-molding/radial stretching of the original cylindrical tube of ePTFE. The anchor covering portion of the sleeve and the intestinal bypass sleeve are formed integrally into one sleeve. The one end of the tube is started to be inverted inside to pull it inside to form an interior tube layer for the expandable anchor. 
         FIG. 81C  is a drawing of an alternative embodiment of the final formed shape of the ePTFE tube after blow-molding/radial stretching of the original cylindrical tube of ePTFE. The anchor covering portion of the sleeve and the intestinal bypass sleeve are formed integrally into one sleeve. The one end of the tube is fully inverted inside forming an interior layer for the expandable anchor. 
         FIG. 82A  is a drawing of an alternative embodiment of the final formed shape of the ePTFE tube after blow-molding/radial stretching of the original cylindrical tube of ePTFE. The anchor covering portion of the sleeve and the intestinal bypass sleeve are formed integrally into one sleeve. The small diameter end of the tube is inverted inside to pull it inside to form an interior tube layer for the expandable anchor. The interior tube is formed into the shape of anti-reflux valve. 
         FIG. 82B  is a drawing of an alternative embodiment of the final formed shape of the ePTFE tube after blow-molding/radial stretching of the original cylindrical tube of ePTFE. The anchor covering portion of the sleeve and the intestinal bypass sleeve are formed integrally into one sleeve. The small diameter end of the tube is inverted inside to pull it inside to form an interior tube layer for the expandable anchor. The interior tube is formed into the shape of a restrictive stoma. 
         FIG. 82C  is a drawing of an alternative embodiment of the final formed shape of the ePTFE tube after blow-molding/radial stretching of the original cylindrical tube of ePTFE. The anchor covering portion of the sleeve and the intestinal bypass sleeve are formed integrally into one sleeve. The small-diameter end of the tube is inverted inside to pull it inside to form an interior tube layer for the expandable anchor. The interior tube is formed into the shape of a restrictive stoma and then an anti-reflux valve in series. 
         FIG. 83A  is a drawing of an alternative embodiment of the final formed shape of the ePTFE tube after blow-molding/radial stretching of the original cylindrical tube of ePTFE. The anchor covering portion of the sleeve and the intestinal bypass sleeve are formed integrally into one sleeve. The small-diameter end of the tube is inverted inside to pull it inside to form an interior tube layer for the expandable anchor. The interior tube is formed into the shape of a restrictive stoma and then an anti-reflux valve in series. 
         FIG. 83B  is a drawing of an alternative embodiment of the final formed shape of the ePTFE tube after blow-molding/radial stretching of the original cylindrical tube of ePTFE. The anchor covering portion of the sleeve and the intestinal bypass sleeve are formed integrally into one sleeve. The small-diameter end of the tube is inverted inside to pull it inside to form an interior tube layer for the expandable anchor. The intestinal bypass sleeve has annular rings or corrugations molded into it to allow for the sleeve to bend easier without kinking and to provide for more longitudinal elasticity. 
         FIG. 84  is a drawing of an alternative embodiment of the embodiment shown in  FIG. 46 . The expandable anchor is comprised of a hollow tubular braided structure of wire. The wire form has been shaped to conform to the shape of the pylorus and the duodenal bulb. Optional barbs and/or hooks provide for additional tissue penetration and anchoring. 
         FIG. 85  is a drawing of an expandable anchor. The expandable anchor incorporates optional barbs and/or hooks have been incorporated into the anchor to provide for tissue penetration and additional anchoring. 
         FIG. 86  is a drawing of an expandable anchor. The expandable anchor incorporates optional barbs and/or hooks have been incorporated into the anchor to provide for tissue penetration and additional anchoring. 
         FIG. 87  is a drawing of an expandable anchor. The expandable anchor incorporates optional barbs and/or hooks have been incorporated into the anchor to provide for tissue penetration and additional anchoring. 
         FIG. 88  is a drawing of an expandable anchor. The expandable anchor incorporates optional barbs and/or hooks have been incorporated into the anchor to provide for tissue penetration and additional anchoring. 
         FIG. 89  is a drawing of an expandable anchor in which the anchors antral disk is larger in diameter than the duodenal bulb disk. 
         FIG. 90  is a drawing of an expandable anchor. 
         FIGS. 91-94  show various embodiments of anti-reflux valves for use in conjunction with an expandable anchor. 
         FIGS. 95-96  show various embodiments of anti-reflux valve frames having flexing posts for use in conjunction with an expandable anchor. 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a sectional view of an embodiment of the invention implanted in a portion of a human digestive tract. As a person ingests food, the food enters the mouth  100 , is chewed, and then proceeds down the esophagus  101  to the lower esophageal sphincter at the gastro-esophageal junction  102  and into the stomach  103 . The food mixes with enzymes in the mouth  100  and in the stomach  103 . The stomach  103  converts the food to a semi-fluid substance called chyme. The chyme enters the pyloric antrum  104  and exits the stomach  103  through the pylorus  106  and pyloric orifice  105 . The pylorus (or pyloric sphincter) is a band of muscle that functions to adjust the diameter of the pyloric orifice, which in turn effects the rate at which chyme exits the stomach. The pylorus (or phyloric sphincter) also has a width (or thickness), which is the distance that the pylorus extends between the stomach and the duodenum. The small intestine is about 21 feet long in adults. The small intestine is comprised of three sections: the duodenum  112 , jejunum  113  and ileum (not shown). The duodenum  112  is the first portion of the small intestine and is typically 10-12 inches long. The duodenum  112  is comprised of four sections: the superior, descending, horizontal and ascending. The duodenum  112  ends at the ligament of treitz  109 . The papilla of vater  108  is the duct that delivers bile and pancreatic enzymes to the duodenum  112 . The duodenal bulb  107  is the portion of the duodenum which is closest to the stomach  103 . As shown, an intestinal bypass sleeve  111  is implanted in the duodenum from the pyloric antrum  104  and pylorus  106  to the ligament of treitz  109 . The intestinal bypass sleeve  111  is held in place at the pylorus  106  by an expandable anchor  110  that anchors on the pylorus  106 . 
     In various exemplary embodiments, the sleeve  111  is integrally formed with or coupled to the expandable anchor  110 . According to other exemplary embodiments, the sleeve  111  is removably or releasably coupled to the expandable anchor  110 . According to various embodiments, the bypass sleeve has a diameter of between about 10 mm and about 35 mm. According to various embodiments, the bypass sleeve has a thickness of between about 0.001 and about 0.015 inches. Exemplary structures for removably or releasably coupling or attaching the sleeve  111  to the expandable anchor  110  are disclosed for example in U.S. patent application Ser. No. 12/752,697, filed Apr. 1, 2010, entitled “Modular Gastrointestinal Prostheses,” which is incorporated herein by reference. According to various embodiments, the sleeve  111  or the expandable anchor  110  (or both) are further coupled at the pylorus  106  using one or more of the techniques described in either of U.S. patent application Ser. No. 12/752,697 or U.S. patent application Ser. No. 12/833,605, filed Jul. 9, 2010, entitled “External Anchoring Configuration for Modular Gastrointestinal Prostheses,” both of which are incorporated herein by reference. According to various embodiments of the invention, the sleeve  111  may be configured and coupled to the expandable anchor  110 , using one or more of the configurations disclosed in U.S. patent application Ser. No. 12/986,268, filed Jan. 7, 2011, entitled “Gastrointestinal Prostheses Having Partial Bypass Configurations,” which is incorporated herein by reference. 
       FIG. 2  is a sectional view of a portion of the digestive tract in a human body. As shown, an endoscope  114  has been inserted through: the mouth  100 , esophagus  101 , stomach  103  and pyloric antrum  104  to allow visualization of the pylorus  106 . Endoscopes  114  are used for diagnostic and therapeutic procedures in the gastrointestinal tract. The typical endoscope  114  is steerable by turning two rotary dials  115  to cause deflection of the working end  116  of the endoscope. The working end of the endoscope or distal end  116 , typically contains two fiber bundles for lighting  117 , a fiber bundle for imaging  118  (viewing) and a working channel  119 . The working channel  119  can also be accessed on the proximal end of the endoscope. The light fiber bundles and the image fiber bundles are plugged into a console at the plug in connector  120 . The typical endoscope has a working channel in the 2.6 to 3.2 mm diameter range. The outside diameter is typically in the 8 to 12 mm diameter range depending on whether the endoscope is for diagnostic or therapeutic purposes. 
       FIG. 3A  is a drawing of an over-the-wire sizing balloon  121  that is used to measure the diameter of the pylorus  106 , duodenal bulb  107 , esophagus  102 , pyloric antrum  104  or other lumen in the GI tract. The sizing balloon is composed of the following elements: proximal hub  122 , catheter shaft  124 , distal balloon component  125 , radiopaque marker bands  126 , distal tip  127 , guidewire lumen  128 , inflation lumen  129 . Distal balloon component  125  can be made from silicone, silicone polyurethane copolymers, latex, nylon 12, PET (Polyethylene terephthalate) Pebax (polyether block amide), polyurethane, polyethylene, polyester elastomer or other suitable polymer. The distal balloon component  125  can be molded into a cylindrical shape, into a dogbone or a conical shape. The distal balloon component  125  can be made compliant or non-compliant. The distal balloon component  125  can be bonded to the catheter shaft  124  with glue, heat bonding, solvent bonding, laser welding or suitable means. The catheter shaft can be made from silicone, silicone polyurethane copolymers, latex, nylon 12, PET (Polyethylene terephthalate) Pebax (polyether block amide), polyurethane, polyethylene, polyester elastomer or other suitable polymer. Section A-A in  FIG. 3A  is a cross-section of the catheter shaft  124 . The catheter shaft  124  if shown as a dual lumen extrusion with a guidewire lumen  128  and an inflation lumen  129 . The catheter shaft  124  can also be formed from two coaxial single lumen round tubes in place of the dual lumen tubing. The balloon is inflated by attaching a syringe (not shown) to a luer fitting side port  130 . The sizing balloon accommodates a guidewire through the guidewire lumen from the distal tip  127  through the proximal hub  122 . The sizing balloon can be filled with saline or a radiopaque dye to allow visualization and measurement of the size of the anatomy with a fluoroscope. The sizing balloon  121  has two or more radiopaque marker bands  126  located on the catheter shaft to allow visualization of the catheter shaft and balloon position. The marker bands  126  also serve as fixed known distance reference points that can be measured to provide a means to calibrate and determine the balloon diameter with the use of the fluoroscope. The marker bands can be made from tantalum, gold, platinum, platinum iridium alloys or other suitable material. 
       FIG. 3B  shows a rapid exchange sizing balloon  134  that is used to measure the diameter of the pylorus  106 , duodenal bulb  107 , esophagus  101 , pyloric antrum  104  or other lumen in the GI tract. The sizing balloon is composed of the following elements: proximal luer  131 , catheter shaft  124 , distal balloon component  125 , radiopaque marker bands  126 , distal tip  127 , guidewire lumen  128 , inflation lumen  129 . The materials of construction will be similar to that of  FIG. 4A . The guidewire lumen  128  does not travel the full length of the catheter. It starts at the distal tip  127  and exits out the side of the catheter at distance shorter than the overall catheter length. The guidewire  132  is inserted into the balloon catheter to illustrate the guidewire path through the sizing balloon. The sizing balloon catheter shaft changes section along its length from a single lumen at section B-B  133  to a dual lumen at section A-A at  124 . An alternative hourglass-shaped balloon  590  can be used for sizing the pylorus anatomy without dilating the pylorus aperture. 
       FIG. 4  is a sectional view of a portion of the digestive tract in a human body. As shown, an endoscope  114  is inserted through the mouth  100 , esophagus  101  and stomach  103  up to the pylorus  106 . An over the wire sizing balloon  121  is inserted through the working channel  119  of the endoscope  114  over a guidewire and is advanced across the pyloric opening  105 . The balloon is inflated with saline or contrast media to a low pressure to open the pylorus  106 , pyloric antrum  104  and duodenal bulb  107  and to allow measurements to be taken. 
       FIG. 5  is a sectional view of the pyloric antrum  104 , pylorus  106 , duodenal bulb  107  and duodenum  112 . An expandable anchor  110  and intestinal bypass sleeve  111  is implanted into the pylorus  106 . The expandable anchor  110  is shown here without a covering material to allow for better visualization of the expandable anchor  110 . In various exemplary embodiments, the expandable anchor  110  is not covered, while in other exemplary embodiments, it is covered with a polymer membrane made from a material such as silicone, polyurethane, polytetrafluoroethylene, fluorinated ethylene propylene, polyethylene, expanded polytetrafluoroethylene or other suitable material.  FIG. 11 , for example, shows an embodiment of the expandable anchor  110  covered with a polymer film. The expandable anchor  110  can be made from metal or plastic. The intestinal bypass sleeve  111  can vary in length from 1-2 inches in length up to several feet. In some embodiments, the sleeve bypasses the length of the duodenum up to the ligament of treitz. While various embodiments disclosed herein describe the intestinal bypass sleeve as extending into the duodenum, in all such embodiments, it is also contemplated that the intestinal bypass sleeve has a length sufficient to allow it to extend partially or fully into the jejunum. The intestinal bypass sleeve  111  may be made from a thin-walled polymer material such as silicone, polyurethane, polytetrafluoroethylene, fluorinated ethylene propylene, polyethylene, expanded polytetrafluoroethylene (ePTFE) or other suitable material. In exemplary embodiments, the wall thickness of the intestinal bypass sleeve  111  maybe in the range of 0.001 inch to 0.010 inch thick. The intestinal bypass sleeve  111  may be made by extrusion, into a tubular form or a lay flat tubing, dip coated from a liquid solution, powder coated from fine particles of polymer or paste extruded and then stretched as is the case with ePTFE. As shown in  FIG. 5 , the intestinal bypass sleeve  111  may have optional helical reinforcements  135  made from a polymer or metal applied to the outer, inner or within the wall thickness of the sleeve. The helical reinforcement can provide for additional kink resistance and prolapse resistance. The wind angle  136  of the helical reinforcement, in exemplary embodiments, has a high pitch angle (for example, 45 degrees) to allow the diameter of the intestinal bypass sleeve to compress easily. According to various embodiments, the wind angle  136  is in the 10 to 85 degrees range. The helical reinforcement may be made integral with the intestinal bypass sleeve or it may be added in a secondary process by bonding on a monofilament(s)  137  of polymer or wire to the surface of the sleeve. 
       FIG. 6  is a drawing of an expandable anchor  110 . The expandable anchor  110  provides for an anchoring means to hold an intestinal bypass sleeve  111  within the small intestine. In exemplary embodiments, the expandable anchor  110  is designed to allow the anchor to be of a self expanding design. A self expanding anchor design can be compressed in diameter to allow the device to be compressed in diameter to be loaded onto a delivery catheter. The anchor  110  can then recover elastically to the original starting diameter, with the anchor diameter decreasing only a small amount due to non elastic recovery. The anchor  110  can also be made of a plastically deformable design and require a mechanical force applied to it in the radial or longitudinal direction to accomplish the expansion of the anchor. The mechanical force can be accomplished with an inflatable balloon type device, radially expanding the anchor  110 , or it may also be accomplished by a longitudinal compression of the anchor  110  by a screw type mechanism or cable tensioning means. As shown, the anchor  110  has a proximal portion or proximal disk  144  that is comprised of 26 spring arms. 
     As shown, the anchor  110  has a distal portion (e.g., open-ended cylindrical portion)  143  that is comprised of 26 spring arms. According to various embodiments, the anchor  110  could have from 3 to 72 spring arms for the proximal disk and the open ended cylinder. 
     According to exemplary embodiments, the expandable anchor  110  is made from a nickel titanium alloys (Nitinol). Other alternative suitable alloys for manufacturing the anchor  110  are stainless steel alloys: 304, 316L, BioDur® 108 Alloy, Pyromet Alloy® CTX-909, Pyromet® Alloy CTX-3, Pyromet® Alloy 31, Pyromet® Alloy CTX-1, 21Cr-6Ni-9Mn Stainless, 21Cr-6Ni-9Mn stainless, Pyromet Alloy 350, 18Cr-2Ni-12Mn Stainless, Custom 630 (17Cr-4Ni) Stainless, Custom 465® Stainless, Custom 455® Stainless Custom 450® Stainless, Carpenter 13-8 Stainless, Type 440C Stainless, cobalt chromium alloys-MP35N, Elgiloy, L605, Biodur® Carpenter CCM alloy, Titanium and titanium alloys, Ti-6Al-4V/ELI and Ti-6Al-7Nb, Ti-15Mo, Tantalum, Tungsten and tungsten alloys, pure platinum, platinum-iridium alloys, platinum-nickel alloys, niobium, iridium, conichrome, gold and gold alloys. The anchor  110  may also be comprised of the following absorbable metals: Pure Iron and magnesium alloys. The anchor  110  may also be comprised of the following plastics: Polyetheretherketone (PEEK), polycarbonate, polyolefins, polyethylenes, polyether block amides (PEBAX), nylon 6, 6-6, 12, Polypropylene, polyesters, polyurethanes, polytetrafluoroethylene (PTFE) Poly(phenylene sulfide) (PPS), poly(butylene terephthalate) PBT, polysulfone, polyamide, polyimide, poly(p-phenylene oxide) PPO, acrylonitrile butadiene styrene (ABS), Polystyrene, Poly(methyl methacrylate) (PMMA), Polyoxymethylene (POM), Ethylene vinyl acetate, Styrene acrylonitrile resin, Polybutylene. The anchor  110  may also be comprised of the following absorbable polymeres: Polyglycolic acid (PGA), Polylactide (PLA), Poly(ε-caprolactone), Poly(dioxanone) Poly(lactide-co-glycolide). 
     The anchor  110 , according to exemplary embodiments, is laser cut from a round tubing or from a flat sheet of Nitinol and then is rolled into a cylindrical shape after laser cutting. The flat representation of the anchor  110  is shown in  FIG. 7 . The anchor  110 , according to exemplary embodiments, is made from a Nitinol tube of about 9 mm outside diameter by a wall thickness of 0.006 inch thick. Alternatively a starting tube outside diameter can range from about 2 mm to 16 mm. An alternative construction method is to laser cut or chemical etch the pattern form a flat sheet of Nitinol with a thickness of 0.002 inch to 0.020 inch. 
     According to various embodiment, anchor  110  has an inside diameter  139  in the range of about 2 mm to 20 mm, Anchor  110  has an expanded open end  137  in the range of about 12 mm to 60 mm. Anchor  110  has a disk-shaped feature  144  that has a diameter  145  in the range of about 12 to 60 mm. Anchor  110  has a central cylinder  138  that has an outside diameter in the range of 4 to 20 mm. Anchor  110  has a flange  141  adjacent to large diameter open end that has a length of about 8 mm in length. According to various embodiments, this length  141  could range from a length of about 1 mm to 30 mm in length. Central cylinder section  138  can have a length  140  of about 1 mm to 30 mm. In various embodiments, the length of the cylinder section  138  is about equal to a width of the pylorus  106  (e.g., the phyloric sphincter). The proximal disk can have a length of 1 mm to 20 mm. The proximal disk  144  can alternatively be formed in the shape of a sphere. The central cylinder  138 , in various embodiments, is made from a material having a stiffness sufficient to resist compressive forces applied by the pylorus. 
       FIG. 7  is a drawing of a flat representation of the circumference of the expandable anchor  110  disclosed in  FIG. 6 . The anchor  110  can be laser cut from a round tubing or flat sheet of Nitinol. In some embodiments of the anchor  110 , the edge  146  connects with edge  147  to form a round tubing. 
       FIG. 8  is a drawing of a flat representation of the circumference of an alternative embodiment of an anchor  148  as disclosed in item  110  of  FIG. 6 . The expandable  148  anchor can be laser cut from round tubing or a flat sheet of Nitinol. The individual spring arm elements of the anchor are cut at a bias angle  149  to the longitudinal axis. The bias angle  149  can range from about 1 degree to about 45 degrees. In some embodiments of the anchor  148 , the edge  150  connects with edge  151  to form a tubing having a round cross-section. 
       FIG. 9  is a drawing of heat set mandrels for heat setting (i.e., form the shape of) the anchor from the laser cut shape of  FIG. 7  and  FIG. 8  to the final shape of the anchor in  FIG. 6 . Female external mandrel  153  is made in two pieces in a clamshell arrangement. Internal mandrel  152  is placed within the external mandrel  153  and forms a cavity  154  in between the two mandrels and provides a means to shape set the Nitinol laser cut parts as in  FIG. 7  and  FIG. 8  into formed shape of anchor in  FIG. 6 . Laser cut part of  FIG. 7  or  FIG. 8  is placed into mold made of items  153  and  152 . Mold and anchor is placed in an oven or salt bath at a temperature in the range of 400 to 500 degrees centigrade and held for 10 minutes. The mold and anchor is then rapidly cooled by air or a water bath. An alternative method to heat set the anchor uses a male only mandrel  155 . The laser cut part is longitudinally compressed and clamped on the mandrel  155  to form the shape of the proximal disk. 
       FIG. 10  is a cross-sectional drawing of a delivery catheter for the invention herein disclosed. The delivery catheter is composed of the three coaxial components: distal outer sheath  170 , which transitions down to a smaller diameter at the proximal outer sheath  182 , proximal pusher catheter  171 , and sleeve advancement pusher  172 . There are three handles on the catheter: outer sheath handle  173 , proximal pusher handle  174 , and sleeve advancement pusher handle  175 . The implant pusher  178  serves as a mechanical stop or means to hold stationery or push out the anchor rings  179  or implant from the inside of the distal outer sheath  170 . The distal tip  176  provides for a flexible tip that will track over a guidewire. The guidewire may be inserted through the central lumen  177 . The proximal shoulder of the tip  181  is rolled back over the end of the intestinal bypass sleeve  180  to constrain the intestinal bypass sleeve  180  to distal tip  176  and the sleeve advancement pusher  172  and to provide a mechanism of advancement of the intestinal bypass sleeve through the duodenum (and the jejunum as applicable). Expandable anchor  179  and the intestinal bypass sleeve  180  are compressed and loaded onto the delivery catheter. 
     The distal outer sheath  170  may be made from a plastic polymer such as Pebax (polyether block amide), hytrel (polyester elastomer), nylon 12, nylon 11, nylon 6, nylon 6,6, polyethylene, polyurethane or other suitable polymer. The distal outer sheath  170  may have an inner lining made from a polymer with a low coefficient of friction such as PTFE. The distal outer sheath  170  may also have a metal re-enforcement in the wall thickness to improve the kink resistance or burst properties of the outer sheath. The metal re-enforcement may be comprised of a braided wire mesh or a coil in the wall thickness. The metal used for the braid may be stainless steel, Nitinol, MP35N, L605, Elgiloy or other suitable material. The distal outer sheath  170  may be from 1-2 inches long up to full length of the catheter. 
     The proximal outer sheath  182  may be made from a plastic polymer such as Pebax (polyether block amide), Hytrel (polyester elastomer), nylon 12, nylon 11, nylon 6, nylon 6,6, polyethylene, polyurethane or other suitable polymer. The proximal outer sheath  182  may have an inner lining made from a polymer with a low coefficient of friction such as PTFE. The proximal outer sheath  182  may also have a metal re-enforcement in the wall thickness to improve the kink resistance or burst properties of the outer sheath. The metal re-enforcement may be comprised of a braided wire mesh or a coil in the wall thickness. The metal used for the braid may be stainless steel, Nitinol, MP35N, L605, Elgiloy or other suitable material. 
     The proximal pusher catheter  171  may be made from a plastic polymer such as Pebax (polyether block amide), Peek, Hytrel (polyester elastomer), nylon 12, nylon 11, nylon 6, nylon 6,6, polyethylene, polyurethane or other suitable polymer. The proximal pusher catheter  171  may have an inner lining made from a polymer with a low coefficient of friction such as PTFE. The proximal pusher catheter  171  may also have a metal re-enforcement in the wall thickness to improve the kink resistance or burst properties of the outer sheath. The metal re-enforcement may be comprised of a braided wire mesh or a coil in the wall thickness. The metal used for the braid may be stainless steel, Nitinol, MP35N, L605, Elgiloy or other suitable material 
     The sleeve advancement pusher  172  may be made from a plastic polymer such as Pebax (polyether block amide), Peek, Hytrel (polyester elastomer), nylon 12, nylon 11, nylon 6, nylon 6,6, polyethylene, polyurethane or other suitable polymer. The sleeve advancement pusher  172  may have an inner lining made from a polymer with a low coefficient of friction such as PTFE. The sleeve advancement pusher  172  may also have a metal re-enforcement in the wall thickness to improve the kink resistance or burst properties of the outer sheath. The metal re-enforcement may be comprised of a braided wire mesh or a coil in the wall thickness. The metal used for the braid may be stainless steel, Nitinol, MP35N, L605, Elgiloy or other suitable material. The sleeve advanced pusher  172  may have a hollow core to allow passage over a guidewire or it may be solid without an opening. The sleeve advanced pusher  172  may also be constructed of a simple tightly wound metal wire coil construction or it may be wound from multiple wires such as Hollow Helical Strand tube made be Fort Wayne Metals. The sleeve advancement pusher handle  175  may also be comprised of a solid tube of Peek, Nitinol or stainless steel. The solid tube may have a series of slots or a patterned on a portion of the tube length to increase the flexibility of the component as required. 
     The distal tip  176  may be molded from Pebax, polyurethane, Hytrel or other suitable elastomer. The distal tip  176  had an outer flange  181  that is soft and may rolled back and the intestinal bypass sleeve  180  inserted under it to secure the sleeve during transport to the distal duodenum (and the jejunum as applicable). 
     The delivery catheter handles may be molded or machined from metal or plastic. The outer sheath handle  173  is attached to the proximal outer sheath  182 . The outer sheath handle  173  is used to hold or retract the distal outer sheath  170  and the proximal outer sheath  182  during the advancement of the delivery catheter into the human anatomy, and while deploying of the anchoring rings. The proximal pusher handle  174  is attached to the proximal pusher catheter  171 . The outer sheath handle  173  is used to hold or push forward the proximal pusher catheter  171  and the implant pusher  178  during the advancement of the delivery catheter into the human anatomy, and while deploying of the anchoring rings. 
     An exemplary deployment sequence consists of the following: The delivery catheter of  FIG. 10  is preloaded with the expandable anchor  179  and the intestinal bypass sleeve  180 . The delivery catheter is advanced through the mouth  100 , esophagus  101  and stomach  103  to the pylorus  106 . The sleeve advancement pusher handle  175  is pushed distally while holding the rest of the catheter stationary. This pushes the sleeve advancement pusher handle  175 , the distal tip  176  and the intestinal bypass sleeve  180  into the duodenum (and jejunum as applicable). The pusher handle  175  is further advanced until the intestinal bypass sleeve  180  reaches the ligament of treiz. At this point all the slack in the sleeve  180  is taken up and the sleeve pulls out from the distal tip  176  and is released from the distal tip  176 . 
       FIG. 11  is a sectional view of the invention herein disclosed implanted into a pylorus  106 , duodenal bulb  107  and duodenum  112 . The expandable anchor  110  is covered with a membrane  186 ,  185  on both inside and outside surfaces of the anchor  110  to close the openings between the spring arm elements  187 . An intestinal bypass sleeve  111  is attached to the expandable anchor  110 . The membrane covering the expandable anchor may be made from a thin-walled polymer material such as silicone, polyurethane, polytetrafluoroethylene, fluorinated ethylene propylene, polyethylene, expanded polytetrafluoroethylene (ePTFE) or other suitable material. In exemplary embodiments, the wall thickness of the membrane covering the expandable anchor may be in the range of 0.001 inch to 0.030 inch thick. The membrane may be made by extrusion, dip coating from a liquid solution, powder coated from fine particles of polymer, or paste extruded and then stretched (e.g., as is typically done with ePTFE). The expandable anchor  110  membrane  185 ,  186  may also be cut from a flat sheet of material such as ePTFE and then bonded or sewn into a disk shape or spherical shaped structure and then attached the expandable anchor  110  frame work by sewing or gluing with a polymer such as FEP. The expandable anchor  110  has a recovery ring  188  attached to the proximal disk to provide for a location to grab the device for removal from the human body. Expandable anchor  110  has a central tube  194  bonded at location  195 , but is free to telescope at location  196  as the anchor  110  is compressed in diameter and elongated in length to allow loading onto a delivery catheter. The central tube  194  may be made from a thin-walled metal material such as stainless steel, titanium or polymer material such as silicone, polyurethane, polytetrafluoroethylene, fluorinated ethylene propylene, polyethylene, expanded polytetrafluoroethylene (ePTFE) or other suitable material. 
       FIG. 12  is a sectional view of recovery catheter  197  for removing the expandable anchor  110  and intestinal bypass sleeve  111  from the human gastrointestinal tract. Recovery catheter has an outer sheath  189 , an inner sheath  190 , grasper forceps  191 , central obturator  192 , and a guidewire lumen  193 . To remove the expandable anchor  110  and the intestinal bypass sleeve  111 , the recovery catheter  197 , with a guidewire inserted through the central obturator  192 , is advanced through the mouth  100 , esophagus  101 , stomach  103 , pyloric antrum  104  up to the pylorus  106 . The obturator  192  is inserted into the central lumen of the recovery ring  188 . The outer sheath  189  is pulled back to expose and allow the grasper forceps  191  to open. Grasper forceps  191  is pushed forward over the recovery ring  188  and the outer sheath  189  is the advanced to collapse grasper forceps  191 . The central obturator  192  and grasper forceps  191  is then pulled into the outer sheath  189  by retraction of the inner sheath  190 . The expandable anchor  110  is then fully collapsed and removed by retraction of the anchor  110  fully into the outer sheath  189 .  FIG. 13  is a sectional view of the expandable anchor  110  in the collapsed state within the outer sheath  189  of the recovery catheter covering and constraining the expandable anchor  110 . 
       FIG. 14  is a sectional view of an alternative embodiment of the invention herein disclosed implanted into a pylorus  106 , duodenal bulb  107  and duodenum  112 . The expandable anchor  110  is covered with a membrane on both the inside  186  and outside  185  surfaces of the anchor  110  to close the openings in between the spring arm elements  187 . An intestinal bypass sleeve  111  is attached to the expandable anchor  110 . The membrane covering the expandable anchor may be made from a thin-walled polymer material such as silicone, polyurethane, polytetrafluoroethylene, fluorinated ethylene propylene, polyethylene, expanded polytetrafluoroethylene (ePTFE) or other suitable material. In some embodiments, the wall thickness of the membrane covering the expandable anchor  186  and  185  may be in the range of 0.001 inch to 0.030 inch thick. The membrane  186  and  185  may be made by extrusion, dip coating from a liquid solution. Powder coated from fine particles of polymer or paste extruded and then stretched as is the case with ePTFE. The expandable anchor  110  membrane  185 ,  186  may also be cut from a flat sheet of material such as ePTFE and then bonded or sewn into a disk-shaped or spherical-shaped structure and then attached to the expandable anchor  110  framework by sewing or gluing with a polymer such as FEP. The expandable anchor  110  has a recovery ring  188  attached to the proximal disk to provide for a location to grab the device for removal from the human body. Expandable anchor  110  has a central tube  199 , which may be bonded at locations  195  and/or  200 . The central tube  199  is comprised of an elastomeric material and can elongate in length as the anchor  110  is compressed in diameter and elongated in length to allow loading onto a delivery catheter. 
     The central tube  199  may be made from a thin-walled polymer material such as silicone, polyurethane, polytetrafluoroethylene, fluorinated ethylene propylene, polyethylene, expanded polytetrafluoroethylene (ePTFE) or other suitable material. 
       FIG. 15  is a sectional view of the invention herein disclosed implanted into a pylorus  106 , duodenal bulb  107  and duodenum  112 . The expandable anchor  110  is covered with a membrane on the outside  185  surface of the anchor  110  to close the openings in between the spring arm elements  187 . An intestinal bypass sleeve  111  is tapered in diameter and attaches to the expandable anchor  110  at location  195 . Intestinal bypass sleeve  111  is sized to fit the duodenum in the duodenal portion and is tapered  201  from the larger diameter to the smaller diameter at  196 . Intestinal bypass sleeve  111  is not attached to the expandable anchor at  196 , but is allowed to slide and telescope within the expandable anchor as it is compressed in diameter to load the anchor onto a delivery catheter. The membrane covering the expandable anchor  185  may be made from a thin-walled polymer material such as silicone, polyurethane, polytetrafluoroethylene, fluorinated ethylene propylene, polyethylene, expanded polytetrafluoroethylene (ePTFE) or other suitable material. In some embodiments, the wall thickness of the membrane covering the expandable anchor  185  may be in the range of 0.001 inch to 0.030 inch thick. The membrane  185  may be made by extrusion, dip coating from a liquid solution, powder coated from fine particles of polymer or paste extruded and then stretched as is the case with ePTFE. The expandable anchor  110  membrane  185  may also be cut from a flat sheet of material such as ePTFE and then bonded or sewn into a disk shape or spherical shaped structure and then attached to the expandable anchor  110  frame work by sewing or gluing with a polymer such as FEP. The expandable anchor  110  has a recovery ring  188  attached to the proximal disk to provide for a location to grab the device for removal from the human body. 
       FIG. 16  is a cross-sectional drawing of the invention herein disclosed implanted into a pylorus  106 , duodenal bulb  107  and duodenum  112 . The rings are sized large enough in diameter that there is a contact force between the ring diameter and the stomach pyloric antrum  104  and the duodenal bulb  107 . The expandable anchor  110  is larger in diameter than the maximum opened diameter of the pylorus and therefore provides an anchoring means to hold the intestinal bypass sleeve  111 . The intestinal bypass sleeve  111  can vary in length from 1-2 inches in length up to several feet. In some embodiments, the sleeve bypasses the length of the duodenum  112  up to the ligament of treitz  109 . The intestinal bypass sleeve  111  can also be longer and bypass into the jejunum. The central tube  194  can be made from a rigid cylinder made from plastic material such as delrin, peek, high density polyethylene, polycarbonate or other suitable polymer. The central tube  194  may also be made from stainless steel, titanium or Nitinol. The fixed diameter of the central tube  194  of the device can be sized to provide for a full opening of the pylorus and not allow the pylorus to close normally. In various embodiments, the diameter of the central tube  194  ranges from as small as 3 mm in diameter up to as large as 14 mm in diameter. The central lumen of device has a one-way anti-reflux valve  202 . The anti-reflux valve  202  allows for unobstructed flow in the direction from the stomach antrum  104  to the pylorus  106 , but limits flow in the reverse direction. The anti-reflux valve  202  can be constructed of a duck bill design with two flexible leaflets  203 , or may utilize other designs such as a tri leaflet valve  204  or quad leaflet valve  205 . The anti-reflux valve may be constructed of silicone or polyurethane, polyethylene, ePTFE or other suitable polymer. In various embodiments, the anti-reflux valve functions to close an end of the bypass sleeve  111 . 
     The central cylinder  194  may also be constructed to have a flow limiter  206 . Flow limiter  206  is an orifice that can be added to limit the maximum flow rate of chyme through the central cylinder  202 . Inflatable flow limiter  207  may also be added to the central cylinder  194  to provide for an adjustable means to change the orifice size. Cylindrical hollow balloon  208  on the inside of the central cylinder  194  can be inflated with air  209 , saline or a cross-linkable polymer such as silicone to reduce the orifice size. Alternatively the central cylinder  194  may also designed to have an optional removable fixed orifice  210 . Fixed orifice  210  may be inserted before the device is implanted in a human or it can be added or size changed at a later date in the future if it is so desirable. Fixed orifice  210  can be held into central cylinder  194  by a magnetic attraction means, snap fit or mechanical interlock feature. A mechanical stop  211  can limit how far the fixed orifice  210  inserts into the central cylinder  194 . An alternative embodiment of a flow limiter may also include a compressible mechanical cage structure  213 . The cage structure  213  has a thin tubular membrane  214  on the inside. The inside diameter of cage structure  213  can be reduced to  212  by axial compression of the length of the cage structure  213 , by screwing in collar  215  into inside diameter of central cylinder  194 . An additional alternative embodiment of a flow limiter can be configured to include an obstruction device  216  that is adjustable in position to change the gap  217  to effectively provide for an adjustable flow limiter. Adjustable flow limiter  216  or  208  may be driven by a motorized method and be adjusted remotely from outside of the patient at a later time by telemetry or magnetic induction. 
       FIG. 17  is an alternative embodiment of  FIG. 16 , wherein the anti-reflux valve is constructed of a ball  218  and cage  219  design. When the ball  218  is all the way towards the cage  219  the valve is all the way open and allows flow of chyme from the pyloric antrum  104  to duodenum  112 . When the ball  218  is up against the valve seat  220  it is closed and the retrograde flow from the duodenum  112  to the stomach  103  should be minimized. The ball  218  and cage  219  may be constructed of metal or plastics. A bi-leaflet  221  valve may also be suitable for the reflux valve. The leaflets are in an open position  223  and a closed position  222 .  FIG. 18  is a drawing of an alternative embodiment of an expandable anchor  224 . Expandable anchor  224  is comprised of a proximal expandable disk  225 , a distal expandable disk  226 , a central cylinder  227  and spring arms  228 . The function and materials are similar to the anchor disclosed in  FIG. 6 . According to various embodiments, the spring arms of the expandable disks extend away from the longitudinal axis at an angle of between about 45 and about 135 degrees. 
       FIG. 19  is a cross-sectional drawing of expandable anchor disclosed in  FIG. 18  and an intestinal bypass sleeve implanted into a pyloric antrum  104 , pylorus  106  and duodenal bulb  107  and duodenum  112 . As shown in  FIG. 19 , the disks  225  and  226  extend radially outward at an angle of between about 10 and about 30 degrees from perpendicular. 
       FIG. 20  is a drawing of an alternative embodiment of an expandable anchor  229 . Expandable anchor  229  is comprised of a proximal expandable cylinder  230 , a distal expandable cylinder  231 , a central cylinder  232  and spring arms  233 . The function and materials are similar to the anchor disclosed in  FIG. 6 . According to various embodiments, the proximal cylinder  230  further includes a wire, suture, or drawstring  283 . The drawstring  283  may be used to facilitate collapse and removal of the expandable anchor  229  from the patient.  FIG. 21A  is a drawing of a flat representation of the expandable anchor shown in  FIG. 20 . Cell geometry is shown in the expanded state  234  and in the compressed state  235 .  FIG. 21B  shows embodiments of cylindrical mandrels  236 A,  236 B for heat setting the expandable anchor to the hour glass shape as in  FIG. 20 . 
       FIG. 22  is a drawing of an alternative embodiment of an expandable anchor. Expandable anchor is comprised of a proximal disk  237 , a distal disk  238 , a central cylinder  239 . The central cylinder  239  is laser cut or machined from Nitinol, titanium, stainless steel or other suitable metal. Alternatively central cylinder is molded from a plastic material previously disclosed in this application. According to various embodiments, the disks of  237  and  238  are laser cut from a flat sheet of Nitinol in a pattern as in  240  and then heat set into the final shape as in  237  and  238 . Formed disk  237  and  238  may be snap fit onto annular groove  242  of central cylinder  239  by placing hole  241  over annular groove  242 . Expandable anchor may be covered with a polymer covering as previously disclosed in this application. According to various embodiments, the disks  237 ,  238  extend outwardly substantially perpendicular to a longitudinal axis of the anchor. 
       FIG. 23  is a drawing of an alternative embodiment of an expandable anchor. Expandable anchor is comprised of a proximal disk  243 , a distal disk  244 , a central cylinder  245 . Central cylinder  245  is machined from Nitinol, titanium, stainless steel or other suitable metal. Alternatively central cylinder is molded from a plastic material previously disclosed in this application. Disk of  243  and  244  may be formed from Nitinol wire in a pattern as in  246 . Formed disk  246  may be snap fit onto annular groove  247  of central cylinder  247  by placing hole  248  over annular groove  247 . Expandable anchor may be covered with a polymer covering as previously disclosed in this application.  FIG. 24  is a drawing of expandable anchor of  FIG. 23  in a compressed state, with a sheath  249  constraining the anchor on the outside diameter. 
       FIG. 25  is a drawing of an alternative embodiment of an expandable anchor formed from wire. Expandable anchor can be formed from a single Nitinol wire form  250 . Central cylinder  251  can be attached to wire form  250  by laser welding or adhesive bonding. Wire may be made from Nitinol, stainless steel, Elgiloy, L605, MP35N titanium, niobium or other suitable metal. The wire can be made of a solid wire, stranded wire or braided. The outer diameter or inner core of the wire may be clad or plated with gold, tantalum, plantium, iridium or other suitable material. The wire may be co-drawn (e.g., drawn filled tube—Fort Wayne Metals) and have an outer core of a high strength material such as Nitinol, stainless steel, Elgiloy, L605, titanium, niobium and an inner core of a high radio-opacity material such as gold, tantalum, plantium, iridium. Alternatively, the wire is made from plastic monofilament. 
       FIG. 26  is a drawing of an alternative embodiment of an expandable anchor made from wire. Expandable anchor can be made from a Nitinol wire form as in  253 . Wire form  253  is attached to central cylinder  254  by inserting wire ends  256  into a receptacle in central cylinder  254 . Wire ends of wire form  253 , inserted into the central cylinder  254  may be attached to central cylinder by mechanical crimping or adhesive bonding or laser welding. Expandable anchor may be covered with ePTFE as previously disclosed to form an hour glass shaped cylinder or selective portions  255  can be covered like flower petals. The wire can be made of a solid wire, stranded wire or braided. 
       FIG. 27  is a drawing of an alternative embodiment of an expandable anchor formed from wire. Expandable anchor can be formed from Nitinol wire forms  260  and  261 . Nitinol wire forms  260  and  261  are disk-shaped and are attached to central cylinder  257 , proximal cylinder  258  and distal cylinder  259  by inserting wire ends into receptacles  262  in cylinders  257 ,  258  and  259 . Wire ends of the wire form  260  and  261  are inserted into the central cylinder  257  and may be attached to central cylinder by mechanical crimping or adhesive bonding or laser welding. The wire can be made of a solid wire, stranded wire or braided. 
       FIG. 28  is a drawing of an alternative embodiment of an expandable anchor. Expandable anchor is comprised of outer rings  263 ,  267 , inner rings  264 ,  268  and wires  269 . Rings and wire may be made from Nitinol, stainless steel, Elgiloy, L605, MP35N, titanium, niobium or other suitable material. Alternatively, the rings and wire may be made from plastics such as Nylon, FEP, PTFE, Delrin, PET, peek, high density polyethylene, polycarbonate or other suitable polymer. Outer ring  263  and inner ring  264  and wire  269  are bonded together by fusing of the materials together for example by laser or TIG welding. Entire annular space  270  between ring  264  and ring  263  can be melted and reflowed together to close up the annular space  270  and combine  263 ,  264  and  269  (and also  267 ,  268  and  269 ) into one solid mass at the outer ends of the ring. Individual wires  269  are not bonded except in the area near the outer ends of the rings. Alternatively, the rings  263 ,  264 ,  267 ,  268  and wires  269  are bonded together by spot welding or adhesive bonding. The wires may be in the form of round wires  269 , flat wires  265 , or stranded wires  266 . After the rings and wires have been joined together the rings  263  and  267  can be compressed towards each other axially to reduce the axial spacing between the rings and cause the wires  269  to bend and cause the original cylinder shape to transform into a disk-shaped anchor  270 . Alternatively the anchor can be shaped to form a spherical shape or a barrel shape. The diameter of the rings  263 ,  264 ,  267 ,  268  can range from 3 to 14 mm in diameter and the outer diameter of the disk  270  can range in the 12 to 50 mm diameter range in the expanded state and in the 3 to 14 mm diameter in the unexpanded state. The anchor can be actuated from the collapsed state to the actuated state by mechanical means or by the elastic properties of the wires  269  which can allow the anchor to self open to the disk-shaped state without mechanical actuation. 
       FIG. 29  is a drawing of anchor previously disclosed in  FIG. 28  in which the anchor is formed into alternative shapes. Ring  263  can be rotated in the opposite direction from ring  267  to form wires  269  to an alternative pattern in which the wires  269  are formed into patterns as in  270  or  271 . Shape  272  is a disk-shaped anchor with a wire pattern of  270  or  271 . Shape  274  is a concave shaped disk, wires  269  may be formed into the pattern of  270 ,  271  or as in  FIG. 28 . Shape  273  is a spherical shaped anchor. Shape  275  is an alternative shape to form the disk. 
       FIG. 30  is a drawing of an assembly of two of the expandable anchors previously disclosed in  FIG. 28  and  FIG. 29 . Anchors  276  and  277  can be any of the alternatives from  FIG. 28  and  FIG. 29 . The anchors are assembled onto a central cylinder  278 . The spacing  280  between the two anchors can be adjusted to accommodate different pylorus widths. Expandable anchors can be covered with a polymer as previously disclosed in this application.  FIG. 31  is a cross-sectional view of the pyloric antrum  104 , pylorus  106 , duodenal bulb  107  and the duodenum  112  in the human body. An expandable anchor as disclosed in  FIG. 28 ,  FIG. 29  and  FIG. 30  and intestinal bypass sleeve  111  is implanted across the pylorus. 
       FIG. 32  is a drawing of an alternative embodiment of an expandable anchor formed in the shape of a toroidal-shaped coil compression spring  282 . The toroidal-shaped anchor may be first formed by winding a straight compression spring  281 . The compression spring  281  may be made from round wire  286 , rectangular wire  287 , square wire  288  or elliptical wire  289 . The compression spring  281  can be wound to have a round shape  290 , rectangular shape  291 , square shape  292 , or an elliptical shape  293 . The wire may be made from Nitinol, stainless steel, Elgiloy, L605, MP35N titanium, niobium or other suitable metal. The wire is, in various embodiments, made of a solid wire but can alternatively be made of stranded or braided wire. The outer diameter or inner core of the wire may be clad or plated with gold, tantalum, plantium, iridium or other suitable material. The wire may be co-drawn (e.g., drawn filled tube—Fort Wayne Metals) and have an outer core of a high strength material such as Nitinol, stainless steel, Elgiloy, L605, MP35N, titanium, niobium and an inner core of a high radio-opacity material such as gold, tantalum, plantium, iridium. Alternatively, the wire is made from a plastic monofilament such as peek, PET or delrin. Compression spring  281  is formed into a toroidal shape by bending spring ends towards each other and joining spring ends at connector  295 . A perspective view of the torroidal spring is shown in  294 . A drawstring  283  is contained within the center of the toroidal spring  282 . The drawstring  283  is threaded through a hole in the connector  295 . Drawstring  283  is terminated at spheres  284  that can be crimped onto the end of the drawstring  283 . The spheres may be made of metal or plastic and may be attached to the drawstring  283  by crimping, welding, gluing, insert molding or other suitable means. The drawstring may be comprised of plastic or metal and may be made of a monofilament or braided cable material. When spheres  284  are withdrawn from connector  295 , drawstring  283  is tensioned and the diameter of the toroidal spring is reduced to the smaller diameter as in  285 . 
       FIG. 33A  is a drawing of an alternative embodiment of an expandable anchor formed in the shape of a toroidal-shaped coil as previously disclosed in  FIG. 32 . The coil may have small tissue penetrating anchors  296  on the outer surface of the coil. Tissue penetrating anchor  296  may be made from, stainless steel, Elgiloy, L605, MP35N, titanium or niobium and may be crimped onto the wire or welded. Tissue penetrating anchors  296  may be an optional feature that can be added if the patient&#39;s anatomy does not have a pyloric ring that is adequate for anchoring.  FIG. 33B  is a drawing of an alternative embodiment of an expandable anchor formed in the shape of a toroidal-shaped coil as previously disclose in  FIG. 32 . The toroidal-shaped spring is formed of segments where the direction of the winding of the coil is reversed to cancel out the helical twisting action of the spring. The individual segments  297 ,  298 ,  299  and  300  can be connector at joiners  301 . Alternatively the entire toroidal spring can be laser cut as one unitary piece by laser cutting the wound coil in the unformed shape as in  281  from a piece of round tubing.  FIG. 33C  is a drawing of an alternative embodiment of an expandable anchor formed in the shape of a toroidal-shaped coil as previously disclose in  FIG. 32 . The spring is wound to have double helices that are 180 degrees offset from each other. 
       FIG. 34A  is an alternative embodiment of a toroidal spring that is made from laser cutting a pattern into a round piece of Nitinol tubing. The Nitinol tubing is laser cut in the straight tubular shape and then the cut tube is then formed into the toroidal shape. Spring elements  301  and  302  elastically bend when the diameter of the toroidal spring is reduced. Bending of elements  301  and  302  reduces the included angles  303  and  309  and space  304  reduces to allow the diameter of toroidal spring to be compressed.  FIG. 34B  is an alternative embodiment of a toroidal spring that is made from laser cutting a pattern into a round piece of Nitinol tubing. The Nitinol tubing is laser cut in the straight round tubular shape and then it is formed into the toroidal shape. Alternatively the part may be cut from a flat sheet of Nitinol and then shape set into the final shape. Spring elements  306  and  305  elastically bend when the diameter of the toroidal spring is reduced. Bending of elements  306  and  305  reduces the included angles  307  and angle  308  to allow the diameter of the toroidal spring to be compressed. 
       FIG. 35  is a drawing of an alternative embodiment of an expandable anchor as disclosed in  FIG. 32  and  FIG. 33 . Toroidal-shaped springs  310 ,  311  and  312  are joined together side-by-side and integrated into an anchor together. In various embodiments, 1 to 3 springs will typically be used together, but in some configurations up to 100 springs may be joined side-by-side at some small spacing. Spring  316 ,  317  and  318  are assembled in a coaxial arrangement (one spring coaxial within the center of another) to provide for a combined spring with increased compression resistance. The direction of the spring winding for the three coaxial springs may be alternated. Springs  313 ,  314  and  315  are also coaxial springs that are wound in an elliptical shape. 
       FIG. 36  is an assembly drawing of an expandable anchor assembly. Expandable anchor assembly comprises two toroidal springs  327  as previously disclosed which are placed into pockets  322  to form disks  319  and  320 , central cylinder  324  is located in between disks  319  and  320 . Pockets  322  are formed from a polymer membrane  321  from materials previously disclosed in this application. Polymer membrane  321  is attached to central cylinder at pins  326 . Outflow opening  325  provides for a location to attach the intestinal bypass sleeve  111 . Inflow opening  323  is positioned towards the pyloric antrum  104 . Drawstring  328  can be withdrawn from the toroidal spring assembly to compress and retrieve the device. 
       FIG. 37  is an assembly drawing of a fixed diameter cylinder for the central pyloric portion of the invention herein disclosed. The central cylinder  324  is ridge and provides a means to attach the polymer membrane to the central cylinder at disks  329  and  330 . Securement rings  331  and  332  penetrate through holes in the polymer membrane and into holes in the central cylinder. Securement rings  331  and  332  can be fastened to the disks  329  and  330  by diameter interference of the pins with the holes, by welding, gluing or mechanical fasteners. 
       FIG. 38  is drawing of a central cylinder pyloric portion for use with any of the anchor embodiments herein disclosed in which the mid-portion allows for normal opening and closing of the pylorus. There is a first ring  333  and a second ring  334  which are fixed rigidly together by connector links  335 ,  338  or  337 . The connector links cross through the pyloric aperture  105  while not obstructing the pyloric aperture  105  or limiting opening or closing of the pylorus. In various embodiments, a thin polymeric membrane will be used over both rings  333 ,  334  and will span the space between the two rings as disclosed in  FIG. 39 . The pylorus  106  can close by entering into the space  339  in between rings  333  and  334  to open and close. Rigid linking of rings  333  and  334  provides for a rigid structure to anchor expandable anchors to and helps to keep expandable anchor (disks) oriented in the proper orientation without canting within the pyloric antrum or duodenal bulb. The rigid linking also does not allow rotational movement between the two rings  333  and  334  and still allows for normal opening and closing of the pylorus, Rotational movement between  333  and  334  may cause the pyloric polymer membrane  340  portion to close. The expandable anchors in the pyloric antrum and the duodenal bulb are tethered to the first ring  333  and second ring  334  by a polymer membrane. 
       FIG. 39  is a sectional view of the invention herein disclosed implanted into the pyloric antrum  104 , pylorus  106  and duodenal bulb  107  and duodenum  112 . The anchoring device is comprised of two disk-shaped expandable anchors  341  and  342  that are connected to a central cylinder which has a thin-walled compliant membrane  340  over the central portion to allow opening and closing of the pyloric aperture. Central cylinder has rings  333  and  334  which are linked by a connector link  335 . Compliant membrane  340  is free to open and close with the movement of the pylorus  106 . Expandable anchors  341  and  342  are tethered to rings  333  and  334  by a polymer membrane  343 . 
       FIG. 40  is a sectional view of the invention herein disclosed implanted into the pyloric antrum  104 , pylorus  106 , duodenal bulb  107  and duodenum  112 . The anchoring device is comprised of two disk-shaped expandable anchors  341 ,  342  as previously disclosed in this application that are connected to a rigid central cylinder  344 . The lumen of the anchoring device has a one way anti-reflux valve  346  and a flow limiter  345 . Drawstring  347  can be tensioned to collapse the diameter of the expandable anchors for removal and for loading the device onto a delivery catheter. 
       FIG. 41  is a sectional view of the invention herein disclosed implanted into the pyloric antrum  104 , pylorus  106 , duodenal bulb  107  and duodenum  112 . The anchoring device is comprised of two disk-shaped expandable anchors  341 ,  342  as previously disclosed in this application that are connected to a central cylinder  350 . The tube of central cylinder is elastically compressible in diameter so that the diameter can be compressed from the first state  349  to reduced diameter state  348 . This will provide for a smaller profile on the delivery catheter. In some configurations, the central cylinder can be soft enough to allow pylorus movement to compress the central cylinder and close the central cylinder opening when the pylorus closes. Drawstring  347  can be tensioned to collapse the diameter of the expandable anchors for removal and for loading the device onto a delivery catheter. 
       FIG. 42  is a sectional view of the invention herein disclosed implanted into the pyloric antrum  104 , pylorus  106 , duodenal bulb  107  and duodenum  112 . The anchoring device is comprised of two disk-shaped expandable anchors  341 ,  342  as previously disclosed in this application that are connected to rings  352  and  353 . The rings  353 ,  353  are not rigidly connected to each other. Thin-walled central membrane  351  is connected to the two rings  352  and  353 . Central membrane can open and close with the pylorus. Drawstring  347  can be tensioned to collapse the diameter of the expandable anchors for removal and for loading the device onto a delivery catheter. 
       FIG. 43  is a sectional view of the invention herein disclosed implanted into the duodenal bulb  107  and duodenum  112 . The anchoring device is comprised of two disk-shaped expandable anchors  341 ,  342  as previously disclosed in this application that are connected to a rigid central cylinder  344 . The lumen of the anchoring device has a one way anti-reflux valve  346  and a flow limiter  345 . Drawstring  347  can be tensioned to collapse the diameter of the expandable anchors for removal and for loading the device onto a delivery catheter. 
       FIG. 44  is a sectional view of the invention herein disclosed implanted into the pyloric antrum  104 , pylorus  106 , duodenal bulb  107  and duodenum  112 . The anchoring device is comprised of two disk-shaped expandable anchors  341 ,  342  as previously disclosed in this application that are connected to a rigid central cylinder  344 . Drawstring  347  can be tensioned to collapse the diameter of the expandable anchors for removal and for loading the device onto a delivery catheter. Intestinal bypass sleeve  111  crosses the pylorus  106  and can be compressed shut at  354  by the pylorus  106 . 
       FIG. 45A  is a sectional view of the invention herein disclosed implanted into the pyloric antrum  104 , pylorus  106 , duodenal bulb  107  and duodenum  112 . The anchoring device is comprised of two disk-shaped expandable anchors  341 ,  342  as previously disclosed in this application that are connected to a rigid central cylinder  344 . Additional expandable anchors  355 ,  356 ,  357  and  358  are extended into the pyloric antrum  104 . 
       FIG. 45B  is a drawing of a flat braided expandable anchor made from Nitinol wire. A series of dowels pins  504  is press fit into an aluminum plate in a determined pattern. Eight wires  506  are braided into a flat braid by wrapping the wires around the dowel pins  504  and then braiding one wire over, one wire under. Four wires are braided in each diagonal direction. Wires are doubled up at end locations  505  and  507 . After the braiding pattern is complete, the wires and the plate are heat set in a salt bath at 500 degrees centigrade for 10 minutes and then water quenched to room temperature. Heat set wire flat braid  508  is then removed from the forming fixture and the wires retain the heat set shape mandrel from the fixture. Flat braid  508  is then wrapped around a round mandrel to form a cylinder shaped braid  509 . The wire ends  505  and  507  at the end of the flat braid are joined at  510 . 
       FIG. 46  is a drawing of an alternative embodiment of the invention herein disclosed. The expandable anchor is comprised of a hollow tubular braided structure of wire. The tubular braid can be braided in the diameter range from 10 mm in diameter up to about 70 mm in diameter. The wire diameter can range from 0.001 inch to 0.014 inch. In exemplary embodiments, the number of wire ends in the braid is 96 ends, but it can range from as few as 4 ends up to 256 ends. The wire can be made from a metal such as Nitinol, MP35N, L605, Elgiloy, stainless steel or from a plastic such as Pet, Peek or Delrin or other suitable material. The tubular wire braid is formed into a shape with a disk  360 , a central cylinder portion  363 , cylindrical portion  359 . Wire ends are gathered into bunches  361  and welded together or a sleeve is crimped onto wires to keep the braided ends from fraying and unraveling. Alternatively, the structure could be made from a braid using a single wire end. Central cylinder  363  has a through lumen  362  that allows chyme to flow from the stomach to the duodenum. The central cylinder  363  can be rigid to hold the pylorus  106  open or it may be compliant to allow the opening and closure of through lumen  362  with the pylorus. 
     The length of the device is typically about 50 mm but can range from about 10 mm to 100 mm. The diameter of the cylindrical portion  359  is typically about 25 mm in diameter, but can range from 10 mm to 75 mm. The diameter of the central cylinder portion is typically about 10 mm in diameter but can range from 2 mm up to 25 mm in diameter. The length of the central cylinder  363  is approximately that of the width of the pylorus, but the central cylinder  363  can be slightly longer to provide a gap between central cylinder and pylorus or slightly shorter to provide for a compressive force to be applied to the pylorus. The expandable anchor is compressible in diameter and the diameter can be reduced to about 5 to 10 mm in diameter typically to allow the anchor to be loaded into a catheter. The expandable anchor can be covered on the outside and/or inside side with a polymer membrane covering. The membrane  365  covering the expandable anchor may be made from a thin-walled polymer material such as silicone, polyurethane, polytetrafluoroethylene, fluorinated ethylene propylene, polyethylene, expanded poly tetrafluoroethylene (ePTFE) or other suitable material. In some embodiments, the wall thickness of the membrane covering the expandable anchor may be in the range of 0.001 inch to 0.030 inch thick. The membrane  365  may be made by extrusion, dip coating from a liquid solution, powder coated from fine particles of polymer or paste extruded and then stretched as is the case with ePTFE. The expandable anchor membrane  365  may also be cut from a flat sheet of material such as ePTFE and then bonded or sewn into a disk shape or spherical shaped structure and then attached to the expandable anchor by sewing or gluing with a polymer such as FEP. 
       FIG. 47  is a sectional view of the invention herein disclosed in  FIG. 46  implanted into the pyloric antrum  104 , pylorus  106 , duodenal bulb  107  and duodenum  112 . An intestinal bypass sleeve  111  is attached to the anchor. 
       FIG. 48  is a drawing of an alternative embodiment of the invention herein disclosed in  FIG. 46 . The expandable anchor is comprised of a hollow tubular braided structure of wire. The wire form has been shaped to conform to the shape of the pylorus and the duodenal bulb. The expandable anchor has an annular grove  366  formed in the wall of the duodenal bulb portion of the expandable anchor. The annular groove  366  is sized to provide for a modular connection means between an expandable anchor and intestinal bypass sleeve  111 .  FIG. 49  is a sectional view of the invention herein disclosed in  FIG. 48  implanted into the pyloric antrum  104 , pylorus  106 , duodenal bulb  107  and duodenum  112 . An intestinal bypass sleeve  111  is attached to the anchor at annular groove  366  and anchored with a second expandable anchor  367 . 
       FIG. 50  is a drawing showing the process steps for the manufacturing of the expandable anchor as in  FIG. 46 ,  FIG. 47  and  FIG. 48 . Braided Nitinol wire tube  368  is placed onto mandrel  369 , one clamp  370  is tightened and then the braid is smoothed and longitudinally tightened on the mandrel  369 . The second clamp  370  is then tightened to secure braid  368  onto mandrel. Braid  368 , secured on mandrel  369  is then heat set in a salt bath for 5 minutes at a temperature of 500 degrees centigrade. The mandrel and braid is then removed from the salt bath and rapidly cooled by immersing braid and mandrel into a room temperature water bath. Clamps  370  are then removed from the braid  368  and mandrel  369  and the braid  368  is removed from the mandrel. One end of heat set braid  368  is then inverted through the lumen of  368  to point  371  to form a layer of double braid from the left end to point  371 . Braid is then placed onto mandrel  372  and the left end of braid  372  is lined up to point  373 . End of overlapped braid is located at  371 . Braid is then secured to the mandrel  372  at location  374  by a wire clamp and at locations  375  by two additional clamps. A secondary heat set is then performed on mandrel  372  and braid in a salt bath for 5 minutes at a temperature of 500 degrees centigrade. The mandrel and braid is then removed from the salt bath and rapidly cooled by immersing braid and mandrel into a room temperature water bath. Clamps  374 ,  375  are then removed from the braid and the braid is removed from the mandrel  372 . The braid now has permanently taken on the shape of the mandrel  372  and has the narrow central cylinder  377  shape. The braid length is trimmed at  376 . All the ends of wires in the braid from both layers are at the end of braid at location  376 . Wire ends are gathered and secured at location  378   
       FIG. 51  is a drawing of an alternative embodiment of an expandable anchor  379 . Expandable anchor  379  is comprised of a proximal expandable disk  381 , a distal expandable disk  380 , a central cylinder  382  and spring arms  383 . The function and materials are similar to the anchor disclosed in  FIG. 18 . Spring arms  384  and  385  are formed inwards to form to concave shaped disk surfaces toward the central cylinder  382 . Gap  386  between disks  380  and  381  can be elastically opened and closed by bending spring arms  384  and  385 .  FIG. 52A  is a drawing of a pyloric antrum  104 , pylorus  106 , duodenal bulb  107  and duodenum  112  and of the expandable anchor  379  of  FIG. 52 . The pylorus width is shown by reference  387 .  FIG. 52B  is a drawing of a pyloric antrum  104 , pylorus  106 , duodenal bulb  107  and duodenum  112  and of the expandable anchor  379  of  FIG. 52  implanted into it. The pyloric width  387  is greater than anchor width or gap  386 . The pyloric width  387  has been reduced to a narrower width  388  due to clamping action of the anchor  379 . 
       FIG. 53  is a drawing of an alternative embodiment of an expandable anchor  389 . The function and materials are similar to the anchor disclosed in  FIG. 6 . Spring arms  392  and  391  are formed inwards to form to concave shaped disk surfaces toward the central cylinder  393 . Gap  390  between arms  392  and  391  can be elastically opened and closed by bending spring arms  392  and  391 . Expandable anchor  389  can clamp on the pylorus in a similar manner as disclosed in  FIG. 52   b.    
       FIG. 54  is a drawing of an alternative embodiment of a single disk of expandable anchor  394  that has optional barbs  395  to provide for an additional securing means to the pylorus.  FIG. 55  is a sectional view of the invention herein disclosed implanted into the pyloric antrum  104 , pylorus  106 , duodenal bulb  107  and duodenum  112 . The anchoring device is comprised of two disk-shaped expandable anchors  394  that are connected to a central cylinder  396  and  397 . The central cylinder of the device  396  and  397  in between the two anchor rings  394  can be made from plastic material such as Delrin, peek, high density polyethylene, polycarbonate or other suitable polymer. The central cylinder portion  396 ,  397  may also be made from stainless steel, titanium or Nitinol. The fixed diameter of the pyloric portion pieces  396  and  397  of the device can be sized to provide for a full opening of the pylorus and not allow the pylorus to close normally. The length of the pyloric portion of the device  400  can be adjusted by sliding the outer cylinder  396  over inner cylinder  397  by sliding on the ratcheting mechanism. This will change the spacing between the anchor rings  394  and will allow the device to be adjusted for ring spacing in-situ. It may be desirable to change the ring spacing to accommodate differences in the pylorus  106  dimensions from patient to patient. It may also be desirable to change the length  400  of the central cylinder portion to allow the anchor ring  394  spacing to be adjusted to allow the expandable anchor to put a clamping force on to the pylorus in a longitudinal direction. The mechanism used for  398  and  399  could also be a screw thread arrangement such as a male thread on  398  and a female thread on  399 . In various embodiments, the inside diameter of the central cylinder  396  and  397  ranges from as small as 2 mm in diameter up to as large as 14 mm in diameter. The central lumen of device has a one-way anti-reflux valve  401 . The anti-reflux valve  401  allows for unobstructed flow in the direction of the stomach antrum  104  to the duodenal bulb  107 , but limits flow in the reverse direction. The anti-reflux valve  401  can be constructed of a duck bill design with two flexible leaflets, or may utilize other designs such as a tri-leaflet valve or quad-leaflet valve. The anti reflux valve may be constructed of silicone, polyurethane, polyethylene, ePTFE or other suitable polymer. The diameter of the central cylinder is fixed, but it may also be designed to allow it to be reduced in diameter during loading of the device onto a catheter. 
       FIG. 56  is a sectional view of the invention herein disclosed implanted into the pyloric antrum  104 , pylorus  106  and duodenal bulb  107  and duodenum  112 . The anchoring device is comprised of two toroidal-shaped expandable anchors  402  that are connected to a central cylinder  403 . The diameter of the central cylinder  403  is fixed, but it may also be elastic to allow it to be reduced in diameter during loading of the device onto a catheter. An optional needle  404 , suture, T-bar  405 , hollow helical anchor  406  or screw type anchor  407  is inserted into and/or through the tissue of the pylorus  106 , pyloric antrum  104  or duodenum  107  to provide additional anchoring and securement of the intestinal bypass sleeve  111  anchoring device to the pylorus anatomy  106 . The T-Bar  405  is anchored by a tensioning member  408  and cincher  409 . 
       FIG. 57  is a sectional view of the invention herein disclosed implanted into the pyloric antrum  104 , pylorus  106 , duodenal bulb  107  and duodenum  112 . An expandable ring  402  is sized large enough in diameter to engage the wall of the pyloric antrum  104 . The central portion of the device is constructed of a ridged fixed diameter central cylinder  403 , or alternatively a compressible cylinder or a thin-walled sleeve. An optional needle  404 , suture, T-bar, hollow helical anchor  406  or screw type anchor  407  is inserted into and or through the tissue of the pylorus  106 , pyloric antrum  104  or duodenum  112  to provide additional anchoring and securement of the intestinal bypass sleeve  111  and anchoring device to pylorus anatomy  106  or other suitable location. The T-Bar  405  is anchored by a tensioning member  408  and cincher  409 . 
       FIG. 58  is a cross-sectional view of a portion of the digestive tract in a human body. An intestinal bypass sleeve  111  is implanted in the duodenum  112  from the pylorus  106  to the ligament of treitz  109 . The sleeve is held in place at the pylorus  106  by expandable anchors  410  that anchor on the pylorus  106  optional secondary expandable anchors  411  anchor the intestinal bypass sleeve  111  at additional locations in the duodenum  112  and jejunum  113 . An expandable anchor  412  with an anti-reflux valve is implanted at the gastro esophageal (GE) junction  102  to help resolve gastroesophageal reflux disease (GERD). Reference numbers  414 ,  415 ,  416 ,  417 ,  418  and  419  denote valve designs that have from two to seven flaps in the valve and may be used for the anti-reflux device  413 . 
       FIG. 59A  is a drawing of an alternative embodiment of an expandable anchor. Expandable anchor has a cylindrical portion  420 , spring arms  421 , a central cylinder portion  422 , through lumen  423  and an isometric view of the expandable anchor  427 . Expandable anchor is laser cut from Nitinol tubing and heat set to final shape on a mandrel with processing steps as previously disclosed in this application. Large diameter cylindrical portion  420  has a diameter in the range from 10 to 70 mm.  FIG. 59B  is a drawing of an alternative embodiment of an expandable anchor. Expandable anchor has a cylindrical portion  424 , spring arms  425 , through lumen  426  and an isometric view of the expandable anchor  428 . Expandable anchor is laser cut from Nitinol tubing and heat set to final shape on a mandrel with processing steps as previously disclosed in this application. Large diameter cylindrical portion  424 , according to various embodiments, has a diameter in the range from 10 to 70 mm.  FIG. 59C  is a drawing of an alternative embodiment of an expandable anchor. Expandable anchor  429  is a double-sided version of anchor as in  FIG. 59C .  FIG. 60  is a drawing of  FIG. 59A  and an intestinal bypass sleeve  111  implanted into a pyloric antrum  104 , pylorus  106  duodenal bulb  107  and duodenum  112 . Alternatively,  FIG. 59B  and  FIG. 59C  could also be implanted into the pyloric antrum  104 , duodenal bulb  107 , duodenum  112  or GE junction  102 . 
       FIG. 61A  is a drawing of an intestinal bypass sleeve with a diameter transition from a larger diameter to a smaller diameter. Intestinal bypass sleeve is comprised of three sections: a first tube  430 , a second tube  432 , and a transitional piece  431 . Intestinal bypass sleeve is made from a polymer material such as ePTFE, PTFE, FEP, polyurethane, silicone, polyethylene, cross-linked polyethylene, high density polyethylene, polypropylene or other suitable material. The intestinal bypass sleeve may be dip coated in one-piece with all three components  430 ,  431 , and  432  made into a seamless one-piece unitary structure. Alternatively  430 ,  431  and  432  can be made as separate components and they can be joined by adhesive bonding (such as with silicone adhesive) or FEP hot melt adhesive, or they can be sewn together at seams  434 ,  435 ,  436  using suture such polyester, Nylon, polypropylene, PTFE or ePTFE. Intestinal bypass sleeve may range in diameter from 3 to 80 mm. Intestinal bypass sleeve may have a wall thickness in the range of 0.001 inch to 0.060 inch thick. 
     Intestinal bypass sleeve may be made porous or nonporous. Sleeve may have surface coatings to close up pores of porous membrane. Such as a surface coating of silicone, polyurethane, FEP applied to porous substrate to render it non-permeable. ePTFE is inherently hydrophobic and has some resistance to water penetration, but it may be desirable to have a higher water entry pressure or make ePTFE impermeable. Intestinal bypass sleeve may have a lubricious (or sticky) hydrophilic coating or a hydrogel added to the inner or outer surface to reduce the friction of the surface or to make it easier for food to pass through the liner or to decrease the outer surface coefficient of friction or make the sleeve stay in place better in the intestines. Intestinal bypass sleeve or expandable anchor may be used for drug delivery, delivery of peptides or other therapeutics by incorporating a drug or peptide into the polymer wall thickness of the intestinal bypass sleeve. The drug or peptide may be added directly to the surface of the intestinal liner without a polymer or covalently bonded to the polymer surface. 
     The drug or peptide may be eluted from a surface coating on the sleeve or anchor which incorporates the drug into the coating. Polymers that may be used as a coating to elute a drug include silicone, polyurethane, Polyvinyl Alcohol, Ethylene vinyl acetate, Styrene acrylonitrile, Styrene-Butadiene, Pebax or other suitable polymer. Absorbable polymers that may be used for drug delivery include, Polyglycolic acid (PGA), Polylactide (PLA), Poly(ε-caprolactone), Poly(dioxanone) Poly(lactide-co-glycolide) or other suitable polymer. Other suitable coatings for increased biocompatibility or drug release may include human amnion, collagen Type I, II, III, IV, V, VI-Bovine, porcine, or ovine. The coating on the intestinal bypass sleeve can also take the form of a liquid that can be used to release the drug or peptide include, Vitamin D, A, C, B, E, olive oil, polyethylene glycol, vegetable oils, essential fatty acids, alpha-linolenic acid, lauric acid, linoleic acid, gamma-linolenic acid, palmitoleic acid or other suitable liquids. The drug may serve to increase satiety, to interrupt the secretion of secondary hormones or digestive enzymes, release antibacterial agents to reduce infection, to increase the fibrotic reaction of the intestinal tract, to decrease the fibrotic reaction of the intestinal tract, to target changes in the cellular composition such as decreasing the number of receptor cells in the duodenum. 
     Intestinal bypass sleeve can release cholecystokinin, gastrin, secretin, gastric inhibitory peptide, motilin, glucagon like peptide  1 , bile, insulin, pancreatic enzymes, ghrelin, penicillin, amoxicillin, ampicillin, carbenicillin, cloxacillin, dicloxacillin, nafcillin, oxacillin, penicillin g, penicillin V, Piperacillin, Ticarcillin Aminoglycosides, Amikacin, Gentamicin, Kanamycin, Neomycin, NEO-RX, Netilmicin, Streptomycin, Tobramycin, Carbapenems, Ertapenem, Doripenem, DORIBAX, Emipenem-cilastatin, Meropenem, Cefadroxil, Cefazolin, Cephalexin rapymicin, taxol, vitamin A, vitamin C, vitamin D, vitamin B, vitamin E, fatty acids, oils, vegetable oils, aspirin, somastatin, motilin, trypsinogen, chymotrypsinogen, elastase, carboxypeptidase, pancreatic lipase, amylase, enteroglucagon, gastric inhibitory polypeptide, Vasoactive intestinal peptide, PYY, Peptide Tyrosine Tyrosine, Leptin, Pancreatic polypeptide. 
       FIG. 61B  is a drawing of an alternative embodiment of an intestinal bypass sleeve. First tube  437  a V-shaped notch  438  is cut into the top and bottom surfaces of tube. V-shaped notch  438  is closed by sewing or adhesive bonding to reduce the tube diameter  439 . Intestinal bypass sleeve is made from ePTFE tubing or other polymers as previously disclosed in  FIG. 61A . 
       FIG. 62A  is a drawing of an alternative embodiment of an intestinal bypass sleeve. Intestinal bypass sleeve starts out as a round tube  440 . Slot  441  is cut into sleeve  440  at the top and bottom surfaces. Slot in sleeve  441  is closed by sewing or adhesive bonding at seam  442 . Final tube is an open end tube with a diameter change from the original larger diameter in  440  to the smaller diameter at  441 .  FIG. 62B  is a drawing of an alternative embodiment of an intestinal bypass sleeve. Intestinal bypass sleeve starts out as a round tube  443  of ePTFE. Tube diameter is reduced from  444  to  445  by drawing (pulling) the tube  444  through a reducing die  446 . An optional floating plug  447  can be placed inside of tube during diameter reduction. The final tube is seamless and has a large diameter section  450 , a tapered section  448 , and small diameter section  449 . 
       FIG. 63A  is a drawing of an alternative embodiment of an intestinal bypass sleeve. Intestinal bypass sleeve starts out as a round tube  451  of ePTFE. Tube diameter is increased from 451 to  454  by pulling the tube  451  over a mandrel  452 . Tube  451  moves in direction  453  while mandrel  452  is stationery. The final tube is seamless and has a large diameter section  454 , a tapered section  455 , and small diameter section  456 . An optional final tube configuration has a large diameter section  457  and a tapered section  458 .  FIG. 63B  is a drawing of an alternative embodiment of an intestinal bypass sleeve. Intestinal bypass sleeve is made by rolling up a thin wall sheet of ePTFE around a mandrel and laminating the ePTFE sheet into a tapered tube configuration and sintering or bonding with an adhesive such as FEP. Final tube may have a large diameter section  459  a transition section  460  and a small diameter section  461 . Final wall thickness can be formed by 1 to 20 layers  462 . 
       FIG. 64A  is drawing of a hemispherical shaped covering for an expandable anchor that is assembled from sheet material into a spherical shape. Figure “8” shape  463  is cut from a sheet of ePTFE sheet. Two shapes of  463  are joined together by sewing or adhesive bonding to produce final spherical shape  465 . Spherical shape  465  may have a hole  466  cut through one or both sides to provide for a through hole to allow attachment to an expandable anchor.  FIG. 64B  is a drawing of hemispherical shaped covering for an expandable anchor that is made by radial stretching a tube preform into a spherical shape by blow-molding or mechanical stretching. Starting shape is a tube of ePTFE  467  is tube  467 . Tube  467  is placed into mold  468  and an internal pressure or force is applied to stretch and radially orient the tube  467  to shape of inside of mold  468 . Pressure is released from tube  467  and stretched tube is removed from inside of mold  468 . Final shape of tube after removing from mold  468  is  469 . In  FIG. 64C , reference number  511  is a drawing of a multi-lumen tubing that can be used for an expandable anchor to hold parallel toroidal springs as shown in  FIG. 35 , item  310 ,  311 ,  312 . Reference number  512  is a tubing extrusion with a pre-attached flange to be used with an anchor as shown in  FIG. 39  and  FIG. 65C . 
       FIG. 65A  is drawing of a hemispherical or disk-shaped covering for an expandable anchor that is assembled from sheet material into a spherical or disk shape. Shape  466  is cut from a sheet of ePTFE. Multiple sections of  466  are joined together into a sphere or disk shape by sewing or joining the seams by adhesive bonding. An optional throughhole  472  can be cut through the sphere or disk shape to allow the sphere or disk-shaped membrane to be attached to the expandable anchor.  FIG. 65B  is a drawing of a disk-shaped covering for an expandable anchor that is assembled from sheet material into a disk shape. Shape  473  is cut from a sheet of ePTFE. The two items of  473  are placed back-to-back. The outer rims of the two pieces of  473  are joined together by adhesive bonding with a hot melt of FEP or other suitable adhesive or sewing with suture. The two disks  473  that have been joined together at the outer rim are now inverted or turned inside out to move the seam to the inside of the disks  475 .  FIG. 65C  is a drawing of a hemispherical or disk-shaped covering for an expandable anchor that is assembled from a tube and sheet material into a disk shape. Outer shape toroidal tube  476  is cut from a straight piece of ePTFE tube and formed into a toroid by sewing the tube ends together at  477 . In various embodiments, an expandable anchor as in  FIG. 32  is inserted inside the tube  476  before the two ends of the tube are joined at  477 . Toroidal tube  476  is sewn to flat round disk  479  of ePTFE sheet at  478 . 
       FIG. 66  is a drawing of an expandable anchor with toroidal-shaped anchors  480  and  481 , expandable anchor has an Archimedes type screw pump  484 , drive motor  482 , battery  485 , recharging antennae  486  integrated into the central cylinder  488  or through a lumen of the device. The Archimedes screw pump can be used as a means to help treat gastroparesis by actively pumping chyme from the stomach to the small intestine (e.g., the duodenum). The entire assembly may be placed into the stomach and intestine using an endoscope and delivering the device through the patient&#39;s mouth and stomach to the pylorus. Alternatively some portions of the device may be surgically placed and may not reside entirely within the digestive tract. The pump can also be used in diabetic patients to more precisely control the flow rate of chyme from the stomach to the small intestine. A more constant and controllable flow of chyme will allow the diabetic individual to be able to more accurately control their blood sugar levels. The pump will allow the flow rate of chyme from the stomach to the small intestine to be varied and controlled by the patient. 
     The Archimedes screw  484  is used to control the flow rate of chyme and/or to pump chyme from the pyloric antrum  104  into the duodenum  112 . Battery  485  powers drive motor  482 , drive motor  482  turns drive shaft  487  and in turn the Archimedes screw  484  is rotated and chyme enters input side of Archimedes screw  483  and is pumped through to the output port of pump  489 . Output port of pump may incorporate a duck bill type anti reflex valve to prevent retrograde flow of chyme. The expandable anchor may be used with or without an intestinal bypass sleeve. The battery  485  can be remotely charged by inductive charging via the induction coil or antenna  486 . The control of the motor operation, start stop and rotational speed and direction is control by controller  490 . Controller  490  can be remotely controlled and programmed by telemetry. Controller can communicate with a controller via telemetry on the outside of the patients to change the flow rate of chyme. The Archimedes screw may also be driven magnetically by external magnets (outside the patient) and internal magnets on Archimedes screw pump. 
     The flow rate of chyme can be modified depending on the blood glucose levels of the patient. Blood glucose levels can be continuously monitored by a glucose sensor and the insulin infusion rates and chyme flow rates can be controlled by the motor  482  controlling the Archimedes screw  484  speed. Currently diabetic patients monitor blood glucose levels and then based on their insulin levels inject themselves with insulin either with a syringe or with an infusion pump. Gastric emptying rates vary depending upon the composition of the food eaten. Sugars pass quickly from the stomach into the small intestine and protein and fats move from the stomach into the small intestine more slowly. Blood sugar control can be difficult to manage if the flow rate of chyme from the stomach to the small intestine is unpredictable and in the case of patients with gastroparesis the chyme flow rate can be very slow to zero. The invention herein disclosed will allow for a tighter glucose level control by allowing more precise control of the flow rate of chyme into small intestine and modulating the flow rate of chyme base on blood glucose levels and insulin infusion rate. 
       FIG. 67  is a sectional drawing of a part of the gastrointestinal anatomy, a pyloric antrum  104 , pylorus  106 , duodenal bulb  107  and duodenum  112 . The expandable anchor of  FIG. 66  is implanted into the pyloric antrum  104 , pylorus  106 , duodenal bulb  107  and duodenum  112 . 
       FIG. 68  is a cross-sectional drawing of a portion of the digestive tract in a human body. The expandable anchor of  FIG. 66  is implanted into the pyloric antrum  104 , pylorus  106 , duodenal bulb  107  and duodenum  112 . A secondary Archimedes screw type pump  492  is attached to the first pump by means of a flexible drive shaft  495  and is housed in a hollow flexible cannula  491  that is attached to the expandable anchor. An optional intestinal bypass sleeve  111  is attached to the expandable anchor. A blood glucose monitor sensor and an insulin infusion drug pump can monitor and adjust the flow rate of chyme from the stomach to the small intestine by adjusting the speed of the motor driving the Archimedes screw pump. 
       FIG. 69A  is an alternative embodiment of an expandable anchor. Expandable anchor is comprised of a ring of beads  498  with a through hole drilled through the bead  500 . Beads  498  are threaded onto a tensioning cable  499 . Tension on tensioning cable  499  is maintained by spring  497 . Ring of beads  498  can be deformed into noncircular shape for loading the expandable anchor onto a catheter. The tensioning cable elastically recovers ring shape of beads  498  due to tension exerted by spring on cable. The ring of beads can repeatedly undergo deformation to a non ring shape to a ring shape. 
       FIG. 69B  is an alternative embodiment of an expandable anchor. Expandable anchor is comprised of ring of magnets  502  with a through hole drilled through the magnets  500 . Magnets  498  are threaded onto a cable  499 . Magnets  502  are loaded onto a tensioning cable  503  with the magnetic poles alternating in polarity. Ring of magnets maintain separation by magnetic levitation or magnetic repulsion. Magnets  502  can be deformed into noncircular shape for loading the expandable anchor onto a catheter. The cable and ring of magnets recovers the original ring shape of magnets  502  due to the force exerted by magnets on each other and the cable. The ring of magnets can repeatedly undergo deformation from a non ring shape to a ring shape. 
       FIG. 70A  is drawing of a piece of ePTFE tubing  504  with a tube  505  of silicone or latex inserted through the inside diameter of the ePTFE tube  504 . The ePTFE tube  504  in the final radially expanded shape can be used for covering an expandable anchor used to anchor an intestinal bypass sleeve. The ePTFE covering for the expandable anchor and the intestinal bypass sleeve can be formed into a single unitary tube in some embodiments disclosed. The ePTFE starting tube  504  can be made in a uni-axial or a bi-axial orientation. In some embodiments, the final shape is made by radially expanding the ePTFE tube  504  into the final shape, alternatively the final shape can also be accomplished by wrapping of thin films of ePTFE sheet into the final shape on a mandrel and then laminating them together by sintering the ePTFE layers together with heat or by fusing the ePTFE layers together by using a material such as FEP as a hot melt adhesive. The starting ePTFE tube  504  can range in size from 3 mm to 12 mm with a wall thickness in the range of 0.003 inch to 0.060 inch. The final expanded diameter of the ePTFE tube can range from the original tube diameter up to 7 times diameter increase from the original tube diameter. The ePTFE tube is plastically deformed during the radial expansion and the diameter largely remains at the new diameter with some diameter lost, 1 to 20 percent due to recoil. The final diameter of the radially stretched ePTFE tube can range from 3 mm to as large as 70 mm.  FIG. 70B  is a longitudinal cross-section drawing of the ePTFE tube  504  and silicone tube  505  shown in  FIG. 70A .  FIG. 70C  is a drawing of a forming mold  506 . The forming mold  506  can be made from plastic or metal such as aluminum or stainless steel. The ePTFE tube and silicone tube,  FIGS. 70A and 70B  will be radially stretched and inflated into the shape of inside of the forming mold  506 . The radial expansion of the tube of ePTFE was previously disclosed in  FIG. 64B . Two disk-shaped apertures  507  are machined into inside of the forming mold  506 . 
       FIG. 71A  is a drawing of two forming molds  506  of  FIG. 70C  that are used to provide an enclosed cavity to limit the expansion of the ePTFE tube  504  during the blow-molding (radial stretching process). Forming molds  506  have disk shape apertures  507  machined into them. The ePTFE tube  504  with an inner tube of silicone 505 is place into the forming mold  506 .  FIG. 71B  is a drawing of the forming molds  506  assembled one mold half on top of the other. The ePTFE tube  504  and silicone tube  505  are inserted through the central bore between the two forming mold halves  506 . Central lumen of silicone tube  508  is open and provides for a pathway to introduce pressurized air or liquid into the lumen of silicone tube. Rigid tube  509  surrounds ePTFE tube  504  and silicone tube  505 . The mold  506 , ePTFE tube  504 , silicone tube  505  can by heated to an elevated temperature (e.g., a temperature of between about 30-150 degrees Celsius) to increase the ultimate elongation of the ePTFE tube  504  and the silicone tube  505 . The inside of the silicone tube  508  is pressurized with air or liquid to radially expand the ePTFE tube  504  into the shape of the central bore and apertures  507 . A pressure in the range of 80 psi to 160 psi is typically used to expand the ePTFE tube  504  and the silicone tube  505 . 
       FIG. 72A  is a drawing of the two forming molds  506  opened after the ePTFE tube has been blow molded to the shape of the disk-shaped apertures  507 . The ePTFE tube is now permanently formed into the new final shape  510 .  FIG. 72B  is a drawing of the formed ePTFE tube  510  removed from the mold cavity after the blow-molding/radial stretching process is complete. The ePTFE tube  510  is now permanently formed into the new final hour glass shape.  FIG. 72C  is a drawing of the cross-section of the ePTFE tube  504  and silicone tube  505  inflated while the two tubes are still in the mold of  71 B. After the pressure is released the silicone tube  505  elastically returns to its original starting diameter and the ePTFE tube  504  partially recoil in diameter but loses only about 10 to 20 percent of the inflated diameter. 
       FIG. 73  is a drawing of an alternate embodiment for a shape for the internal cavity for the forming mold  511  for blow-molding the ePTFE tube.  FIG. 74  is a drawing of an alternate embodiment for a shape for the internal cavity for the forming mold  512  for blow-molding the ePTFE tube.  FIG. 75  is a drawing of an alternate embodiment for a shape for the internal cavity for the forming mold  513  for blow-molding the ePTFE tube.  FIG. 76  is a drawing of an alternate embodiment for a shape for the internal cavity for the forming mold  514  for blow-molding the ePTFE tube. 
       FIG. 77A  is a drawing of the shape of the ePTFE tube formed into a double disk shape after blow-molding/radial stretching of the original cylindrical tube of ePTFE. The ends of the radially expanded ePTFE tube shape may be trimmed in length to accomplish the desired final shape.  FIG. 77B  is a drawing of the shape of the ePTFE tube formed into a double disk shape after blow-molding/radial stretching of the original cylindrical tube of ePTFE. The ends of the radially expanded ePTFE tube shape may be trimmed in length to accomplish the desired final shape.  FIG. 77C  is a drawing of the shape of the ePTFE tube formed into a double cup shape after blow-molding/radial stretching of the original cylindrical tube of ePTFE. The ends of the radially expanded ePTFE tube shape may be trimmed in length to accomplish the desired final shape.  FIG. 77D  is a drawing of the shape of the ePTFE tube formed into a disk and cup shape after blow-molding/radial stretching of the original cylindrical tube of ePTFE. The ends of the radially expanded ePTFE tube shape may be trimmed in length to accomplish the desired final shape.  FIG. 77E  is a drawing of the shape of the ePTFE tube formed into a double spherical shape after blow-molding/radial stretching of the original cylindrical tube of ePTFE. The ends of the radially expanded ePTFE tube shape may be trimmed in length to accomplish the desired final shape. 
       FIG. 78A  is a drawing of the final formed shape of the ePTFE tube after blow-molding/radial stretching of the original cylindrical tube of ePTFE. The anchor covering portion  515  of the sleeve and the intestinal bypass  516  sleeve are formed integrally into one sleeve. The length  517  of the intestinal bypass sleeve  516  may range from a few inches up to 4 feet or more. The sleeve may include an optional bulbous shape  518  for the duodenal bulb. The intestinal bypass sleeve length  517  can range from a few inches to 4 feet or more.  FIG. 78B  is a drawing of the final formed shape of the ePTFE tube after blow-molding/radial stretching of the original cylindrical tube of ePTFE. The anchor covering portion  515  of the sleeve and the intestinal bypass sleeve  516  are formed integrally into one sleeve. The small diameter end of the tube  519  is started to be inverted inside to pull it inside to form an interior tube layer for the expandable anchor.  FIG. 78C  is a drawing of the final formed shape of the ePTFE tube after blow-molding/radial stretching of the original cylindrical tube of ePTFE. The anchor covering portion of the sleeve  515  and the intestinal bypass sleeve  516  are formed integrally into one sleeve. The small diameter end of the tube is fully inverted inside forming an interior layer  521  for the expandable anchor. Two pockets  520  are formed with the sleeve, an expandable anchor as previously disclosed in this patent application may be placed within the pockets. 
       FIG. 79A  is a drawing of an alternative embodiment of the final formed shape of the ePTFE tube after blow-molding/radial stretching of the original cylindrical tube of ePTFE. The anchor covering portion of the sleeve  523  and the intestinal bypass sleeve  522  are formed integrally into one sleeve.  FIG. 79B  is a drawing of an alternative embodiment of the final formed shape of the ePTFE tube after blow-molding/radial stretching of the original cylindrical tube of ePTFE. The anchor covering portion of the sleeve  524  and the intestinal bypass sleeve  522  are formed integrally into one sleeve. The end of the tube  527  is started to be inverted inside to pull it inside to form an interior tube layer for the expandable anchor.  FIG. 79C  is a drawing of an alternative embodiment of the final formed shape of the ePTFE tube after blow-molding/radial stretching of the original cylindrical tube of ePTFE. The anchor covering portion of the sleeve  528  and the intestinal bypass sleeve  522  are formed integrally into one sleeve. The end of the tube  527  is fully inverted inside forming an interior layer  526  for the expandable anchor which can be located in pockets  525 . 
       FIG. 80A  is a drawing of an alternative embodiment of the final formed shape of the ePTFE tube after blow-molding/radial stretching of the original cylindrical tube of ePTFE. The anchor covering portion of the sleeve  530  and the intestinal bypass sleeve  529  are formed integrally into one sleeve. The end of the tube  531  is started to be inverted inside to pull it inside to form an interior tube layer for the expandable anchor.  FIG. 80B  is a drawing of an alternative embodiment of the final formed shape of the ePTFE tube after blow-molding/radial stretching of the original cylindrical tube of ePTFE. The anchor covering portion of the sleeve  530  and the intestinal bypass sleeve  529  are formed integrally into one sleeve. The small diameter end of the tube is fully inverted inside to pull it inside to form an interior tube layer  532  for an expandable anchor as previously disclosed. 
       FIG. 81A  is a drawing of an alternative embodiment of the final formed shape of the ePTFE tube after blow-molding/radial stretching of the original cylindrical tube of ePTFE. The anchor covering portion of the sleeve  534  and the intestinal bypass sleeve  533  are formed integrally into one sleeve.  FIG. 81B  is a drawing of an alternative embodiment of the final formed shape of the ePTFE tube after blow-molding/radial stretching of the original cylindrical tube of ePTFE. The anchor covering portion of the sleeve  535  and the intestinal bypass sleeve  533  are formed integrally into one sleeve. The end of the tube  537  is started to be inverted inside to pull it inside to form an interior tube layer for the expandable anchor.  FIG. 81C  is a drawing of an alternative embodiment of the final formed shape of the ePTFE tube after blow-molding/radial stretching of the original cylindrical tube of ePTFE. The anchor covering portion of the sleeve  538  and the intestinal bypass sleeve  533  are formed integrally into one sleeve. The end of the tube is fully inverted inside forming an interior layer  536  for the expandable anchor. The end of the tube is fully inverted inside to pull it inside to form an interior tube layer  532  for an expandable anchor as previously disclosed. An expandable anchor may be place in between the layers at  539 . 
       FIG. 82A  is a drawing of an alternative embodiment of the final formed shape of the ePTFE tube after blow-molding/radial stretching of the original cylindrical tube of ePTFE. The anchor covering portion of the sleeve  541  and the intestinal bypass sleeve  540  are formed integrally into one sleeve. The small diameter end of the tube is inverted inside to pull it inside to form an interior tube layer for the expandable anchor. The interior tube is formed into the shape of anti-reflux valve  542 . The anti reflux valve  542  may be formed of two leaflets  545 , three leaflets  546 , or four leaflets  547 .  FIG. 82B  is a drawing of an alternative embodiment of the final formed shape of the ePTFE tube after blow-molding/radial stretching of the original cylindrical tube of ePTFE. The anchor covering portion of the sleeve  541  and the intestinal bypass sleeve  540  are formed integrally into one sleeve. The small diameter end of the tube is inverted inside to pull it inside to form an interior tube layer for the expandable anchor. The interior tube is formed into the shape of a restrictive stoma  543 .  FIG. 82C  is a drawing of an alternative embodiment of the final formed shape of the ePTFE tube after blow-molding/radial stretching of the original cylindrical tube of ePTFE. The anchor covering portion of the sleeve and the intestinal bypass sleeve are formed integrally into one sleeve. The small diameter end of the tube is inverted inside to pull it inside to form an interior tube layer for the expandable anchor. The interior tube is formed into the shape of a restrictive stoma and then an anti-reflux valve in series  544 . 
       FIG. 83A  is a drawing of an alternative embodiment of the final formed shape of the ePTFE tube after blow-molding/radial stretching of the original cylindrical tube of ePTFE. The anchor covering portion of the sleeve  548  and the intestinal bypass sleeve  549  are formed separately and bonded together. Intestinal bypass sleeve  549  may be formed from FEP or other suitable polymer.  FIG. 83B  is a drawing of an alternative embodiment of the final formed shape of the ePTFE tube after blow-molding/radial stretching of the original cylindrical tube of ePTFE. The anchor covering portion of the sleeve  550  and the intestinal bypass  551  sleeve are formed integrally into one sleeve. The small diameter end of the tube is inverted inside to pull it inside to form an interior tube layer for the expandable anchor. The intestinal bypass sleeve  551  has annular rings or corrugations formed into it to allow for the sleeve to bend easier without kinking and to provide for more longitudinal elasticity. 
       FIG. 84  is a drawing of an alternative embodiment of the invention previously disclosed in  FIG. 46 . The expandable anchor is comprised of a hollow tubular braided structure of wire. The wire form has been heat set or shaped to conform to the shape of the pylorus and the duodenal bulb. Optional barbs and/or hooks  552  that have been incorporated into the anchor to provide for additional tissue penetration and additional anchoring.  FIG. 85  is a drawing of an expandable anchor. The expandable anchor incorporates optional barbs and/or hooks  553  have been incorporated into the anchor to provide for tissue penetration and additional anchoring. The barbs are outwardly oriented to engage the tissue of the pyloric antrum, pylorus and/or duodenal bulb. In various embodiments, the barbs extend outwardly in a direction generally perpendicular to the longitudinal axis. According to other embodiments, the barbs extend at an angle with respect to the longitudinal axis of anywhere between about 0 and about 90 degrees. The lengths of the barbs may range from less than 1 mm up to several mm in length. The barbs may be constructed from Nitinol, titanium, Elgiloy, MP35N, stainless steel, platinum, platinum iridium, plastics or other suitable materials. The design and construction of the expandable anchor is similar to what was previously disclosed in  FIG. 6 . 
       FIG. 86  is a drawing of an expandable anchor. The expandable anchor incorporates optional barbs and/or hooks  554  that have been incorporated into the anchor to provide for tissue penetration and additional anchoring. The design and construction of the expandable anchor is similar to what was previously disclosed in  FIG. 6 .  FIG. 87  is a drawing of an expandable anchor. The expandable anchor incorporates optional barbs and/or hooks  555  that have been incorporated into the anchor to provide for tissue penetration and additional anchoring. The design and construction of the expandable anchor is similar to what was previously disclosed in  FIG. 18 .  FIG. 88  is a drawing of an expandable anchor. The expandable anchor incorporates optional barbs and/or hooks  556  that have been incorporated into the anchor to provide for tissue penetration and additional anchoring. In various embodiments, the barbs extend outwardly in a direction generally perpendicular to the longitudinal axis. According to other embodiments, the barbs extend at an angle with respect to the longitudinal axis of anywhere between about 0 and about 90 degrees. The design and construction of the expandable anchor is similar to what was previously disclosed in  FIG. 20 .  FIG. 89  is a drawing of an expandable anchor in which the expandable anchor&#39;s antral disk  557  is larger in diameter than the duodenal bulb disk  558 . The design and construction of the expandable anchor is similar to what was previously disclosed in  FIG. 18 . 
       FIG. 90  is a drawing of an expandable anchor. The expandable anchor has a central cylinder  559  as previously disclosed in  FIG. 38 . The expandable anchor has an antral disk  560  comprised of Nitinol wire in a braided form and a duodenal disk  561  comprised of Nitinol wire in a braided form. The Nitinol braid can be comprised of a single layer of braid or it may be double back on itself and the cut wire ends of the braid may be attached to the central cylinder at location  589 . The Nitinol wire braid may be shape set or formed into the desired shape by the means previously disclosed in this application. 
       FIG. 91  is a drawing of an anti-reflux valve for an expandable anchor. The anti-reflux valve  562  can be located within the central cylinder as previously disclosed as item  346  in  FIG. 40 . The anti-reflux valve  562  may be made from a thin-walled tube of polymer such as ePTFE, PTFE, FEP, silicone, polyurethane, polyethylene or other suitable polymer. The polymer may be designed with the proper thickness and mechanical properties to allow the valve to self seal or close when retrograde flow is exerted on the valve. The anti-reflux valve may be bonded to the central cylinder  565 . Anti-reflux valve is in an open position  566  when chyme flows from the stomach to the duodenum and in a closed position  563  and  564  when chyme flows in a retrograde direction from the duodenum to the stomach. The anti-reflux valve can allow chyme to flow from the stomach to the duodenum without being restricted, but it can also limit or prevent retrograde flow from the duodenum to the antrum. Retrograde flow from the duodenum to the pylorus can be undesirable and cause eversion of the intestinal bypass sleeve and allow the sleeve to evert through the expandable anchor into the stomach. The anti-reflux valve  562  can be designed to evert and allow retrograde flows at very high pressures such as during vomiting. The inside diameter of the anti-reflux valve in the open state can range from 4 mm to 18 mm in diameter. 
       FIG. 92  is a drawing of an anti-reflux valve for an expandable anchor. The anti-reflux valve  568  can be located within the central cylinder as previously disclosed as item  346  in  FIG. 40 . The anti-reflux valve  568  may be made from a thin-walled tube of polymer such as ePTFE, PTFE, FEP, silicone, polyurethane, polyethylene or other suitable polymer. The anti-reflux valve may be bonded to the central cylinder  567 . Anti-reflux valve  568  can have a rigid ring  571  bonded onto the end of the tube to prevent the anti-reflux valve  568  from being everted through the central cylinder at high pressures. Anti-reflux valve is in an open position  571  when chyme flows from the stomach to the duodenum and in a closed position  569  when chyme flows in a retrograde direction from the duodenum to the stomach. The anti-reflux valve can allow chyme to flow from the stomach to the duodenum without being restricted, but it can also limit or prevent retrograde flow from the duodenum to the antrum. Retrograde flow from the duodenum to the pylorus can be undesirable and cause eversion of the intestinal bypass sleeve and allow the sleeve to evert through the expandable anchor into the stomach. 
       FIG. 93  is a drawing alternative embodiment of an anti-reflux valve for an expandable anchor. The anti-reflux valve  573  can be located within the central cylinder as previously disclosed as item  346  in  FIG. 40 . The anti-reflux valve  573  may be made from a thin-walled tube of polymer such as ePTFE, PTFE, FEP, silicone, polyurethane, polyethylene or other suitable polymer. The tube can be constructed of one extrusion of tubing or it may be made from three individual sections or leaflets joined to form the circumference of the valve. The anti-reflux valve  573  may be bonded to the central cylinder  572 . The polymer tube for the anti-reflux valve  573  can be attached to the metal flexing post  577 . The anti-reflux valve has three flexing posts  577  at a spacing of about 120 degrees around the circumference of the valve. The polymer tube can be attached to the flexing posts by sewing, gluing or other mechanical means. The flexing posts  577  can be made from metals such as Titanium, Nitinol, stainless steel, elgiloy, MP35N, or plastics such as PEEK or delrin or other suitable material. The flexing posts  577  allows the valve to open at low pressures, but holds the valve leaflets so that they do not evert back into the lumen of the central cylinder  572 . Anti-reflux valve is in an open position  574  when chyme flows from the stomach to the duodenum and in a partially closed position  575  and fully closed position  576  when chyme flows in a retrograde direction from the duodenum to the stomach. The anti-reflux valve  573  can allow chyme to flow from the stomach to the duodenum without being restricted, but it can also limit or prevent retrograde flow from the duodenum to the antrum. The inside diameter of the anti-reflux valve in the open state can range from 4 mm to 18 mm in diameter. 
       FIG. 94  is a drawing of an alternative embodiment of an anti-reflux valve for an expandable anchor. The anti-reflux valve  582  can be located within the central cylinder as previously disclosed as item  346  in  FIG. 40 . The anti-reflux valve  582  can be made from a thin-walled tube of polymer such as ePTFE, PTFE, FEP, silicone, polyurethane, polyethylene or other suitable polymer. The tube can be constructed of one extrusion of tubing or it may be made from two individual sections or leaflets joined to form the circumference of the valve. The anti-reflux valve  582  may be bonded to the central cylinder  578 . The polymer tube for the anti-reflux valve  582  can be attached to the metal flexing posts  579 . The anti-reflux valve has two flexing posts  579  at a spacing of about 180 degrees around the circumference of the valve. The polymer tube can be attached to the flexing posts by sewing, gluing or other mechanical means. The flexing posts  579  can be made from metals such as Titanium, Nitinol, stainless steel, elgiloy, MP35N, or plastics such as PEEK or delrin or other suitable material. The space  583  between the flexing posts can be adjusted to increase the pretension on the leaflets and affect the opening pressure of the anti-reflux valve. If the post spacing  583  is increased the leaflets will be under greater tension and the valve opening pressure will be increased. The flexing posts  579  can be designed to allow the valve to open at low pressures, but the posts still hold the valve leaflets so that the leaflets do not evert back into the lumen of the central cylinder  578 . Anti-reflux valve is in an open position  580  when chyme flows from the stomach to the duodenum and in closed position  581  when chyme flows in a retrograde direction from the duodenum to the stomach. The opening pressure of the anti-reflux valve can be designed to be close to zero if little to no flow resistance is desired to the flow of chime from the stomach to the duodenum. To induce additional weight loss in a patient or if a dumping syndrome occurs it may be desirable to have the anti-reflux valve that has a moderate flow resistance in an anti-grade flow direction. The post stiffness or post spacing  583  can be adjusted to customize the desired flow resistance in the antegrade direction while still maintaining the anti-reflux properties of the valve. Thus the anti-reflux valve  582  can be designed to accomplish multiple different functions: provide for an anti-reflux function, valve opens at low pressures in an antegrade flow direction, or valve opens at a higher pressure in the antegrade flow direction. Previous prior art flow limiters consisted of orifice type valves. This provides for a flow limiter that can open easily to a larger diameter to allow large food particles to pass through the valve without the stretching of a polymer orifice and still provide the desired flow resistance. Thus this design provides for a flow limiter without the inherent risk of having the orifice become obstructed with large particles of chyme. The inside diameter of the anti-reflux valve in the open state can range from 4 mm to 18 mm in diameter. 
       FIG. 95  is a drawing of an alternative embodiment of an anti-reflux valve frame with flexing posts. The frame is constructed so the flexing posts  585  are integrated into the wall of the central cylinder  584 .  FIG. 96  is a drawing of an alternative embodiment of an anti-reflux valve frame with flexing posts. The flexing posts can be designed to have holes in the posts  588  or a slot  587  to provide for a means to mechanically attach the leaflets to the flexing posts.