Abstract:
The present invention is related to cerebral embolic protection assemblies (CEPA) to be used during a medical procedure to help redirect or catch emboli before it is pumped into the cerebral circulation. A variety of CEPA&#39;s are disclosed including a perfusion filter catheters and fluid flow dividers for capturing and redirecting potential emboli within the aorta during heart surgery and cardiopulmonary bypass. The catheter devices may further include one or more additional or auxiliary flow control members. Furthermore, oxygenated blood is perfused through a perfusion lumen in the catheter. The present invention describes devices that are capable of capturing and/or redirected emboli away from the cerebral circulation. The devices are configured for percutaneous, intercostal, lateral or central insertion with attendant administration of cardiopulmonary bypass and cardioplegic arrest with protection from undesirable embolic events.

Description:
CROSS REFERENCE TO OTHER APPLICATIONS  
       [0001]    This application is a continuation of application Ser. No. 09/447458, filed Nov. 22, 1999, now U.S. Pat. No. 6,395,014, which is a continuation-in-part of application Ser. No. 09/158,405 filed Sep. 22, 1998, now U.S. Pat. No. 6,361,545, which claims the benefit of U.S. Provisional Application No. 60/060,117 filed Sep. 26, 1997, and a continuation-in-part of application Ser. No. 09/378,676, filed Aug. 20, 1999, now U.S. Pat. No. 6,371,935, which claims the benefit of U.S. Provisional Application No. 60/116,836 filed Jan. 22, 1999. These and all other U.S. patents and patent applications referred to herein are incorporated by reference in their entirety for all purposes. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The present invention relates generally to a catheter or cannula for infusion of oxygenated blood or other fluids into a patient for cardiopulmonary support and cerebral protection. More particularly, it relates to an arterial perfusion catheter with a deployable cerebral embolic protection assembly (CEPA) for protecting a patient from adverse effects due to emboli that are dislodged during cardiopulmonary bypass.  
         BACKGROUND  
         [0003]    Over the past decades tremendous advances have been made in the area of heart surgery, including such life saving surgical procedures as coronary artery bypass grafting (CABG) and cardiac valve repair or replacement surgery. Typically, in order to gain access to the heart a median sternotomy is performed, which creates an open surgical field, conducive for the placement of cannulae and direct visualization for performing the required procedure. Heart activity generally ceases for some period of time, and cardiopulmonary support is provided by diverting blood through an extracorporeal circuit to maintain sufficient oxygenated blood flow to the body and brain while the heart is arrested. Cardiopulmonary bypass (CPB) is a technology that has made these advances possible.  
           [0004]    Recently, however, there has been a growing awareness within the medical community as well as the patient population concerning the adverse affects associated with heart surgery, the large amount of trauma associated with median sternotomies, as well as well the physiological reactions associated with cardiopulmonary bypass. Chief among these concerns is the potential for stroke or neurologic deficit.  
           [0005]    Clinical research has indicated that one of the primary causes of stroke or neurologic deficit is cerebral embolization. Emboli vary in size as well as physical properties and their sources vary. However, embolic materials include atherosclerotic plaques or calcific plaques residing within the ascending aorta or cardiac valves and thrombus or clots from within the chambers of the heart. Emboli may also be dislodged during surgical manipulation of the heart, the ascending aorta, cross-clamping, aortic cannulation or due to high velocity jetting (sometimes called the “sandblasting effect”) from the aortic perfusion cannula. In addition, air can enter the heart chambers or the blood stream during surgery through open incisions or through the aortic perfusion cannula. As blood is pumped to the brain, either through the extracorporeal circuit or by the beating heart in an off-pump minimally invasive procedure, transient or mobile emboli can become lodged in the brain causing a stroke or other neurologic deficit. Clinical studies have shown a correlation between the number and size of emboli passing through the carotid arteries and the frequency and severity of neurologic damage. At least one study has found that frank strokes seem to be associated with macroemboli larger than approximately 100 micrometers in size, whereas more subtle neurologic deficits seem to be associated with multiple microemboli smaller than approximately 100 micrometers in size. In order to improve the outcome of cardiac surgery and to avoid adverse neurological effects it would be very beneficial to eliminate or reduce the potential of such cerebral embolic events.  
           [0006]    Therefore, what has been needed and heretofore unavailable, is a catheter device for standard open chest surgery and for use in minimally invasive medical procedures that is simple and relatively inexpensive. One which is capable of isolating the circulation of the arch vessels, while still allowing the heart to perform the function of perfusing the body or alternatively one that can be used in conjunction with an extracorporeal circuit. The present invention solves these problems as well as others.  
           [0007]    The terms downstream and upstream, when used herein in relation to the patient&#39;s vasculature, refer to the direction of blood flow and the direction opposite that of blood flow, respectively. In the arterial system, downstream refers to the direction further from the heart, while upstream refers to the direction closer to the heart. The terms proximal and distal, when used herein in relation to instruments used in the procedure, refer to directions closer to and farther away from the operator performing the procedure. Since the present invention is not limited to peripheral or central approaches, the device should not be narrowly construed when using the terms proximal or distal since device features may be slightly altered relative to the anatomical features and the device position relative thereto.  
         SUMMARY OF THE INVENTION  
         [0008]    In keeping with the foregoing discussion, the present invention takes the form of a catheter or cannula having a cerebral embolic protection assembly (CEPA) mounted on an elongated tubular catheter shaft. The elongated tubular catheter shaft is adapted for introduction into a patient&#39;s ascending aorta either by a peripheral arterial approach or by a direct aortic puncture. The CEPA has an undeployed state where it is compressed or wrapped tightly around the catheter shaft and a deployed state where it expands to the size of the aortic lumen. The CEPA assembly can be passively or actively deployed. Various mechanisms are disclosed for both passive and active deployment.  
           [0009]    Radiopaque markers and/or sonoreflective markers may be located on the catheter and/or CEPA. Preferably, a perfusion lumen extends through the elongated tubular catheter shaft to one or more perfusion ports upstream and/or downstream of the CEPA. Oxygenated blood is perfused through the perfusion lumen, through the beating heat or a combination of both. Any embolic materials that might be dislodged are captured or rerouted by the CEPA.  
           [0010]    Embodiments are also described that combine the CEPA with an aortic occlusion device, which may be a toroidal balloon, an expandable balloon or a selectively deployable external catheter flow control valve. The combined device allows percutaneous transluminal administration of cardiopulmonary bypass and cardioplegic arrest with protection from undesirable embolic events, as well as differential perfusion.  
           [0011]    In use, the CEPA is introduced into the patient&#39;s aorta, either by a peripheral arterial approach or by direct aortic puncture, with the CEPA in a collapsed state. The CEPA is advanced across the aortic arch and into the arch and ascending aorta. When a portion of the CEPA is positioned in the ascending aorta between the aortic valve and the brachiocephalic artery, the CEPA is either actively or passively deployed. The position of the catheter and the deployment state of the CEPA may be monitored using fluoroscopy, ultrasound, transesophageal echography (TEE) or aortic transillumination using visible, infrared or near infrared light. Once the CEPA is deployed, oxygenated blood may be infused into the aorta through the perfusion lumen or alternatively the beating heart may supply all the blood or a combination of both. Any potential emboli are captured or rerouted by the CEPA and are thereby prevented from entering the neurovasculature. After use, the CEPA is returned to the collapsed position and the catheter is withdrawn from the patient. Methods according to the present invention are described using the aortic catheter for occluding and compartmentalizing or partitioning the patient&#39;s aortic lumen and for performing selective filtered aortic perfusion. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    FIGS.  1 - 3  show a perfusion filter catheter configured for retrograde deployment via a peripheral arterial access point.  
         [0013]    [0013]FIG. 1 is a cutaway perspective view of the perfusion filter catheter deployed within the aorta via femoral artery access.  
         [0014]    [0014]FIG. 2 shows the distal end of the catheter with the embolic filter assembly in a deployed state.  
         [0015]    [0015]FIG. 3 shows the distal end of the catheter with the embolic filter assembly in a collapsed state for insertion or withdrawal of the device from the patient.  
         [0016]    FIGS.  4 - 6  show a method of actively deploying an embolic filter assembly with an inflatable filter support structure.  
         [0017]    FIGS.  7 - 9  show a perfusion filter catheter adapted for antegrade deployment via direct aortic puncture.  
         [0018]    FIGS.  10 - 14  show the operation of an embodiment of a perfusion filter catheter that combines an embolic filter assembly with a toroidal balloon aortic occlusion device.  
         [0019]    [0019]FIG. 15 shows an embodiment of a perfusion filter catheter that combines an embolic filter assembly with an inflatable balloon aortic occlusion device.  
         [0020]    [0020]FIG. 16 shows an embodiment of a perfusion filter catheter that combines an embolic filter assembly with a selectively deployable external catheter flow control valve.  
         [0021]    [0021]FIG. 17 shows an embodiment of a perfusion filter catheter with an embolic filter assembly having areas of different filter porosity.  
         [0022]    [0022]FIG. 18 shows a bottom view of another CEPA of the present invention configured for retrograde deployment via a peripheral artery access point, such as the femoral artery.  
         [0023]    [0023]FIG. 19 shows a side view of the catheter of FIG. 18, showing the CEPA in the form of a divider in the collapsed state.  
         [0024]    [0024]FIG. 20 shows a cross section of the aortic catheter of FIG. 18 taken along line  20 - 20  in FIG. 18.  
         [0025]    [0025]FIG. 21 shows a top view of the catheter of FIG. 18 with the flow divider deployed.  
         [0026]    [0026]FIG. 22 shows a perspective view of an embodiment of the catheter of the invention including a deployed auxiliary flow control member positioned between the flow divider and the distal end of the catheter.  
         [0027]    [0027]FIG. 23 shows a perspective view of the catheter of FIG. 22 with the auxiliary flow control member partially collapsed.  
         [0028]    [0028]FIG. 24 shows an embodiment of the catheter of the invention configured for antegrade deployment.  
         [0029]    [0029]FIG. 25 shows a cut-away view of an embodiment of the flow divider including a mesh or porous portion for perfusing from the upper surface of the flow divider.  
         [0030]    [0030]FIG. 26 shows a cut-away view of an alternate internal structure of the flow divider of FIG. 25.  
         [0031]    [0031]FIG. 27 shows an embodiment of the flow divider of the invention comprising a peripheral tube and membrane structure.  
         [0032]    [0032]FIG. 28 shows a cross section of the flow divider of FIG. 27 taken along line  28 - 28 .  
         [0033]    [0033]FIG. 29 shows an embodiment of the flow divider of the invention with welds or joined areas between an upper and a lower film of the flow divider to give additional structure and rigidity to the flow divider.  
         [0034]    [0034]FIG. 30 shows a cross section of the flow divider of FIG. 29 taken along line  30 - 30  of FIG. 29.  
         [0035]    [0035]FIG. 31 shows an alternate embodiment of FIG. 29 with larger joined areas between the upper and lower films of the flow divider.  
         [0036]    [0036]FIG. 32 shows another embodiment of the flow divider of the invention deployed from a lumen within a catheter.  
         [0037]    [0037]FIG. 33 shows a cross section of the flow divider and aorta of FIG. 32 taken transversely through the aorta. 
     
    
     DETAILED DESCRIPTION  
       [0038]    FIGS.  1 - 3  illustrate a first embodiment of the present invention having a CEPA in the form of a perfusion filter catheter. FIGS.  1 - 3  show a perfusion filter catheter  100  according to the present invention configured for retrograde deployment via a peripheral arterial access point. FIG. 1 is a cutaway perspective view of the perfusion filter catheter  100  deployed within the aorta of a patient via femoral artery access. FIG. 2 shows the distal end of the catheter  100  with the embolic filter assembly  102  in a deployed state. FIG. 3 shows the distal end of the catheter  100  with the embolic filter assembly  102 ′ in a collapsed state for insertion or withdrawal of the device from the patient.  
         [0039]    Referring now to FIG. 1, the catheter  100  includes a cannula shaft having a tubular body  104  and a CEPA in the form of a filter assembly  102 . The tubular body has a proximal end  108  and distal end  110  and is preferably extruded from a flexible thermoplastic material or a thermoplastic elastomer. Suitable materials for the tubular body  104  include, but are not limited to, polyvinylchloride, polyurethane, polyethylene, polypropylene, polyamides (nylons), and alloys or copolymers thereof, as well as braided, coiled or counterwound wire or filament reinforced composites. The tubular body  104  may have a single lumen or multilumen construction. In the exemplary embodiment shown, the catheter  100  has a single perfusion lumen  106  extending from the proximal end  108  to the distal end  110  of the catheter shaft  104 . The perfusion lumen  106  is open at the distal end  110  of the catheter shaft  104 . The distal end  110  of the catheter shaft  104  may have a simple beveled or rounded distal edge, as shown, or it may include additional side ports or a flow diffuser to reduce jetting when oxygenated blood is infused through the perfusion lumen  106 . The proximal end  108  of the elongated tubular catheter shaft  104  is adapted for connecting the perfusion lumen  106  to a cardiopulmonary bypass pump or other source of oxygenated blood using standard barb connectors or other connectors, such as a standard luer fitting (not shown) and suitable medical tubing. Preferably, the catheter shaft  104  is made with thin walled construction to maximize the internal diameter and therefore the flow rate of the perfusion lumen  106  for a given outside diameter and length of the catheter shaft  104 . Thin walled construction also allows the outside diameter of the catheter shaft  104  to be minimized in order to reduce the invasiveness of the procedure and to reduce trauma at the insertion site. The perfusion lumen  106  should be configured to allow sufficient blood flow to preserve organ function without hemolysis or other damage to the blood. For standard cardiopulmonary support techniques, a catheter shaft  104  of 18-24 French size (6-8 mm outside diameter) is sufficient to deliver the requisite 3-4 liters of oxygenated blood to preserve organ function. For low flow cardiopulmonary support techniques, such as described in commonly owned, copending patent application Ser. No. 60/084,835, filed May 8, 1998 and its corresponding utility application Ser. No. 09/306,555 filed on May 6, 1999 which are hereby incorporated by reference, the size of the catheter shaft  104  can be reduced to 9-18 French size (3-6 mm outside diameter) for delivering 0.5-3 liters of oxygenated blood to preserve organ function. The catheter shaft  104  should have a length sufficient to reach from the arterial access point where it is inserted to the ascending aorta of the patient. For femoral artery deployment, the catheter shaft  104  preferably has a length from approximately 80-120 cm.  
         [0040]    A deployable embolic filter assembly  102  is located just proximal to the distal end  110  of the catheter shaft  104 . The embolic filter assembly  102  includes a filter screen  112  made of a fine mesh material. In this exemplary embodiment and each of the other embodiments described below, the fine mesh material of the filter screen  112  may be a woven or knitted fabric, such as Dacron polyester or nylon mesh, or other textile fabrics, or it may be a nonwoven fabric, such as a spun bonded polyolefin or expanded polytetrafluoroethylene or other nonwoven materials. The fine mesh material of the filter screen  112  may be woven, knitted or otherwise formed from monofilament or multifilament fibers. The fine mesh material of the filter screen  112  may also be a fine wire mesh or a combination of wire and textile fibers. Alternatively, the fine mesh material of the filter screen  112  may be an open cell foam material. The fine mesh material of the filter screen  112  must be nontoxic and hemocompatible, that is, non-thrombogenic and non-hemolytic. Preferably, the fine mesh material of the filter screen  112  has a high percentage of open space, with a uniform pore size. The pore size of the filter screen  112  can be chosen to capture macroemboli only or to capture macroemboli and microemboli. In most cases the pore size of the filter screen  112  will preferably be in the range of 1-200 micrometers. For capturing macroemboli only, the pore size of the filter screen  112  will preferably be in the range of 50-200 micrometers, more preferably in the range of 80-100 micrometers. For capturing macroemboli and microemboli, the pore size of the filter screen  112  will preferably be in the range of 1-100 micrometers, more preferably in the range of 5-20 micrometers. In other applications, such as for treating thromboembolic disease, a larger pore size, e.g. up to 1000 micrometers (1 mm) or larger, would also be useful. In some embodiments, a combination of filter materials having different pore sizes may be used.  
         [0041]    Alternatively or additionally the material of the filter screen in each embodiment of the filter catheter may be made of or coated with an adherent material or substance to capture or hold embolic debris which comes into contact with the filter screen within the embolic filter assembly. Suitable adherent materials include, but are not limited to, known biocompatible adhesives and bioadhesive materials or substances, which are hemocompatible and non-thrombogenic. Such materials are known to those having ordinary skill in the art and are described in, among other references, U.S. Pat. Nos. 4,768,523, 5,055,046, 5,066,709, 5,197,973, 5,225,196, 5,374,431, 5,578,310, 5,645,062, 5,648,167, 5,651,982, and 5,665,477. In one particularly preferred embodiment, only the upstream side of the elements of the filter screen are coated with the adherent material to positively capture the embolic debris which comes in contact with the upstream side of the filter screen after entering the filter assembly. Other bioactive substances, for example, heparin or thrombolytic agents, may be impregnated into or coated on the surface of the filter screen material or incorporated into an adhesive coating.  
         [0042]    The embolic filter assembly  102  is movable between a collapsed state, as shown in FIG. 3, and an expanded or deployed state, as shown in FIGS. 1 and 2. The filter screen  112  may be attached directly to the catheter shaft  104  and it may constitute the entire embolic filter assembly  102 , particularly if the filter screen  112  is made of a resilient or semirigid fabric that has enough body to be self-supporting in the deployed state. Generally, however, the embolic filter assembly  102  will also include a filter support structure  114 , particularly if a highly flexible or flaccid material is used for the filter screen  112 . The filter support structure  114  attaches and supports the filter screen  112  on the catheter shaft  104 . In the illustrative embodiment of FIGS.  1 - 3 , the filter support structure  114  is constructed with an outer hoop  116  and a plurality of struts  118  which extend approximately radially from a ring-shaped hub  126  that is mounted on the catheter shaft  104 . In this case four struts  118  are shown, however, two, three or more struts  118  may be used. The open distal end  122  of the filter screen  112  is attached to the outer hoop  116  and the proximal end  120  of the filter screen  112  is sealingly attached to the catheter shaft  104 . When the embolic filter assembly  102  is deployed, the outer hoop  116  of the filter support structure  114  holds the open distal end  122  of the filter screen  112  against the inner wall of the aorta, as shown in FIG. 1. To accommodate most normal adult aortas, the outer hoop  116  of the filter support structure  114  and the distal end  122  of the filter screen  112  have a diameter of approximately 2.5 to 4 cm, plus or minus 0.5 cm. Larger and smaller diameter filter support structures  114  may be made to accommodate patients with distended or Marfan syndrome aortas or for pediatric patients.  
         [0043]    The embolic filter assembly  102  may be deployed by a passive means or by an active means. Passive means for deploying the embolic filter assembly  102  could include using the elastic memory of the filter screen  112  and/or the filter support structure  114  to deploy the embolic filter assembly  102 , and/or using pressure from the blood flow in the aorta to deploy the embolic filter assembly  102 . By contrast, active means for deploying the embolic filter assembly  102  could include one or more actuation members within the catheter shaft  104  for mechanically actuating the filter support structure  114  to deploy the embolic filter assembly  102  from the proximal end  108  of the catheter  100 . Shape memory materials may also be used as actuation members for deploying the embolic filter assembly  102 . Alternatively, active means for deploying the embolic filter assembly  102  could include one or more lumens within the catheter shaft  104  for hydraulically actuating the filter support structure  114  to deploy the embolic filter assembly  102 . Passive means may be used to augment the action of the active deployment means. As shown in FIG. 3, an outer tube  124  may be provided to cover the embolic filter assembly  102  when it is in the collapsed state in order to create a smooth outer surface for insertion and withdrawal of the catheter  100  and to prevent premature deployment of the embolic filter assembly  102 , particularly if passive deployment means are used.  
         [0044]    The perfusion filter catheter  100  is prepared for use by folding or compressing the embolic filter assembly  102 ′ into a collapsed state within the outer tube  124 , as shown in FIG. 3. The distal end  110  of the catheter  100  is inserted into the aorta in a retrograde fashion. Preferably, this is done through a peripheral arterial access, such as the femoral artery or subclavian artery, using the Seldinger technique or an arterial cutdown. Alternatively, the catheter  100  may be introduced directly through an incision into the descending aorta after the aorta has been surgically exposed. The embolic filter assembly  102  is advanced up the descending aorta and across the aortic arch while in the collapsed state. The position of the catheter  100  may be monitored using fluoroscopy or ultrasound, such as transesophageal echography (TEE). Appropriate markers, which may include radiopaque markers and/or sonoreflective markers, may be located on the distal end  110  of the catheter  100  and/or the embolic filter assembly  102  to enhance imaging and to show the position of the catheter  100  and the deployment state of the embolic filter assembly  102 . When the distal end  110  of the catheter  100  is positioned in the ascending aorta between the aortic valve and the brachiocephalic artery, the outer tube  124  is withdrawn and the embolic filter assembly  102  is deployed, as shown in FIG. 1. Optionally, a distal portion of the catheter shaft  104  may be precurved to match the curvature of the aortic arch to aid in placement and stabilization of the catheter  100  and the embolic filter assembly  102  within the aorta. Once the embolic filter assembly  102  is deployed, oxygenated blood may be infused through the perfusion lumen  106  to augment cardiac output of the beating heart or to establish cardiopulmonary bypass so that the heart can be arrested. Any potential emboli are captured by the filter screen  112  and prevented from entering the neurovasculature or other branches downstream. After use, the embolic filter assembly  102  is returned to the collapsed position and the catheter  100  is withdrawn from the patient.  
         [0045]    Preferably, the embolic filter assembly  102  is configured so that, when it is in the deployed state, at least a majority of the filter screen  112  is held away from the aortic walls so that flow through the pores of the filter screen  112  is not occluded by contact with the aortic wall. In addition, this also assures that blood flow into the side branches of the aorta will not be obstructed by the filter screen  112 . In this way, each side branch of the aorta will receive the benefit of flow through the full surface area of the filter screen  112  so that blood flow is not restricted by the area of the ostium of each side branch. In the illustrative embodiment of FIGS.  1 - 3 , the filter screen  112  has a roughly conical shape with an open distal end  122 . The conical shape holds the fine mesh material of the filter screen  112  away from the aortic walls and away from the ostia of the side branches so that blood can flow freely through the pores of the filter screen  112 .  
         [0046]    FIGS.  4 - 6  illustrate a second embodiment of the present invention having an actively deployable CEPA in the form of an embolic filter assembly  202  attached to a perfusion catheter  200 . In this embodiment, the filter support structure  204  includes an outer hoop  206  and a plurality of struts  208 , which are all interconnected hollow tubular members. Preferably, the outer hoop  206  and the struts  208  are made of a flexible polymeric material. The filter support structure  204  is connected to an inflation lumen  210 , which parallels the perfusion lumen  218  within the catheter shaft  212 . At its proximal end, the inflation lumen  210  branches off from the catheter shaft  212  to a side arm  214  with a luer fitting  216  for connecting to a syringe or other inflation device. By way of example, this embodiment of the embolic filter assembly  202  is shown with a trumpet-shaped filter screen  220 . The filter screen  220  includes a skirt portion  222  extending distally from a proximal, filter pocket  224 . The skirt portion  222  is in the shape of a frustum of a cone with an open distal end, which is attached to the outer hoop  206 . The filter pocket  224  is roughly cylindrical in shape with a closed proximal end, which is sealingly attached to the catheter shaft  212 . The skirt  222  and the filter pocket  224  may be made of the same filter material or they may be made of different filter materials having different porosities. The skirt  222  of the filter screen  220  may even be made of a nonporous material.  
         [0047]    The perfusion filter catheter  200  is shown in FIG. 6 with the embolic filter assembly  202  folded into a collapsed position. The outer hoop  206  and the struts  208  of the filter support structure  204  are deflated and the material of the filter screen  220  is folded or collapsed around the catheter shaft  212 . An outer tube  226  covers the embolic filter assembly  202  in the collapsed position to facilitate insertion of the catheter  200 . Optionally, the outer tube  226  may have a slit or a weakened longitudinal tear line along its length to facilitate removal of the outer tube  226  over the side arm  214  at the proximal end of the catheter  200 . Once the perfusion filter catheter  200  is in position within the patient&#39;s aorta, the outer tube  226  is pulled back to expose the embolic filter assembly  202 . Then, the embolic filter assembly  202  is deployed by inflating the outer hoop  206  and the struts  208  with fluid injected through the inflation lumen  210  to actively expand the filter support structure  204 , as shown in FIG. 5. When the embolic filter assembly  202  is deployed, the outer hoop  206  of the filter support structure  204  seals against the inner wall of the aorta, as shown in FIG. 4. Preferably, at least the outer wall of the outer hoop  206  is somewhat compliant when inflated in order to compensate for patient-to-patient variations in aortic luminal diameter.  
         [0048]    FIGS.  7 - 9  illustrate a third embodiment of the present invention having a CEPA in the form of a perfusion filter catheter  300  adapted for antegrade deployment via direct aortic puncture. In this exemplary embodiment, the perfusion filter catheter  300  is depicted with a hybrid-style embolic filter assembly  302 , which is a compromise between a conical filter screen and a trumpet-style filter. Because the catheter  300  is introduced directly into the ascending aorta, the catheter shaft  304  can be reduced to a length of approximately 20-60 cm and an outside diameter of approximately 12-18 French size (4-6 mm outside diameter) for delivering the 3-4 liters of oxygenated blood needed to preserve organ function during cardiopulmonary bypass. One modification that may be made to the catheter  300  for antegrade deployment is to configure it so that the perfusion port or ports  306  which connect to the perfusion lumen  308  exit the catheter shaft  304  proximal to the filter screen  310  so that fluid flow will come from the upstream side of the embolic filter assembly  302 . The catheter shaft  304  need not extend all the way to the distal end of the filter screen  310 . The filter screen  310  may be entirely supported by the filter support structure  312 , particularly if the embolic filter assembly  302  is to be passively deployed. Alternatively, a small diameter filter support member  314  may extend from the catheter shaft  304  to the distal end of the filter screen  310 . If the embolic filter assembly  302  is intended to be actively deployed, the filter support member  314  may be slidably and/or rotatably received within the catheter shaft  304 . Either of these configurations allows the embolic filter assembly  302  to be folded or compressed to a size as small as the diameter of the catheter shaft  304  to facilitate insertion of the catheter  300 . Optionally, an outer tube  316  may be placed over the folded embolic filter assembly  302  to hold it in the collapsed position.  
         [0049]    In use, the ascending aorta of the patient is surgically exposed, using open-chest or minimally invasive surgical techniques. A purse string suture  318  is placed in the ascending aorta and an aortotomy incision is made through the aortic wall. The catheter  300 , with the embolic filter assembly  302  in the collapsed position within the outer tube  316 , is inserted through the aortotomy and advanced antegrade into the aortic arch. When the proximal end of the embolic filter assembly  302  is positioned in the ascending aorta between the aortic valve and the brachiocephalic artery, the outer tube  316  is withdrawn and the embolic filter assembly  302  is either actively or passively deployed, as shown in FIG. 7. Once the embolic filter assembly  302  is deployed, oxygenated blood may be infused into the aorta through the tubular catheter shaft  304 . Any potential emboli are captured by the embolic filter assembly  302  and prevented from entering the neurovasculature or other branches downstream. After use, the embolic filter assembly  302  is returned to the collapsed position, the catheter  300  is withdrawn from the patient, and the purse string suture  318  is tightened to close the aortotomy.  
         [0050]    In general, each of the passive and active deployment methods described above may be used interchangeably or together in combinations with each of the embodiments of the perfusion filter catheter and each of catheter insertion methods which are described above and below. Likewise, many of the features of the embodiments described may be used in various combinations with one another to create new embodiments, which are considered to be a part of this disclosure, as it would be too cumbersome to describe all of the numerous possible combinations and subcombinations of the disclosed features. In general, each of the described embodiments may be passively or actively deployed by the methods described above. Each embodiment of the CEPA described can also be adapted for retrograde deployment via peripheral arterial access, such as femoral or subclavian artery access, or for antegrade or retrograde deployment via direct aortic puncture.  
         [0051]    FIGS.  10 - 12  illustrate a fourth embodiment of the present invention having a CEPA in the form of a perfusion filter catheter  600 . FIG. 10 illustrates the CEPA in a collapsed or undeployed state having an embolic filter assembly  602  with a toroidal balloon aortic occlusion device  604  collapsed or folded about the elongated catheter shaft  606 . The perfusion filter catheter  600  is inserted in the collapsed state and advanced into the patient&#39;s ascending aorta until the embolic filter assembly  602  is positioned between the coronary ostia and the brachiocephalic artery. The toroidal balloon aortic occlusion device  604  is then inflated to expand and deploy the embolic filter assembly  602 , as shown in FIG. 11. The embolic filter assembly  602  may assume a simple conical shape or, more preferably, one of the surface area increasing geometries described above. In addition, the embolic filter assembly  602  may include a structure or other means to hold the filter material apart from the aortic wall to maximize the effective filter area. With the embolic filter assembly  602  deployed, cardiopulmonary bypass with embolic protection can be started through the perfusion ports  610 .  
         [0052]    When it is desired to initiate cardioplegic arrest, the toroidal balloon aortic occlusion device  604  is further inflated until it expands inward to occlude the aortic lumen, as shown in FIG. 12. A cardioplegic agent is infused through the cardioplegia port  608  and into the coronary arteries to arrest the heart. Oxygenated blood continues to be infused through the perfusion ports  610 . After completion of the surgical procedure, the toroidal balloon aortic occlusion device  604  is partially deflated, leaving the embolic filter assembly  602  deployed, as shown in FIG. 13. Oxygenated blood enters the coronary arteries to restart the heart beating. If any embolic materials  612  are dislodged during manipulation of the heart or when the heart resumes beating, they will be captured by the embolic filter assembly  602 . Once the patient is weaned off bypass, the toroidal balloon aortic occlusion device  604  is deflated to collapse the embolic filter assembly  602 , as shown in FIG. 14. Any potential emboli are trapped within the embolic filter assembly  602  and can be removed along with the catheter  600 .  
         [0053]    [0053]FIG. 15 illustrates a fifth embodiment of the present invention having a CEPA in the form of an embolic filter assembly  622  with an inflatable balloon aortic occlusion device  624 . The embolic filter assembly  622  may be any one of the actively or passively deployed embolic filter assemblies described herein. Preferably, the inflatable balloon aortic occlusion device  624  is an elastomeric balloon of sufficient inflated diameter to occlude the ascending aorta and is mounted on the elongated catheter shaft  626  upstream of the embolic filter assembly  622 . Alternatively, the inflatable balloon aortic occlusion device  624  may be positioned to occlude the inlet end of the embolic filter assembly  622  to minimize the area of contact between the perfusion filter catheter  620  and the aortic wall. The inflatable balloon aortic occlusion device  624  is connected to an inflation lumen within the elongated catheter shaft  626 . A cardioplegia lumen, which may also serve as a guidewire lumen, connects to a cardioplegia port  628  at the distal end of the catheter shaft  626 . A perfusion lumen connects to one or more perfusion ports  630  located on the catheter shaft  626  downstream from the inflatable balloon aortic occlusion device  624 , but upstream of the embolic filter assembly  622 . The operation of the perfusion filter catheter  620  of FIG. 15 is quite similar to that described for the embodiment of FIGS.  10 - 14 .  
         [0054]    [0054]FIG. 16 illustrates a sixth embodiment of the present invention having a CEPA in the form of an embolic filter assembly  642  combined with a selectively deployable external catheter flow control valve  644 . The embolic filter assembly  642  may be any one of the actively or passively deployed embolic filter assemblies described herein. The selectively deployable external catheter flow control valve  644  is mounted on the elongated catheter shaft  646  upstream of the embolic filter assembly  642 . Alternatively, the selectively deployable external catheter flow control valve  644  may be positioned to occlude the inlet end of the embolic filter assembly  642  to minimize the area of contact between the perfusion filter catheter  640  and the aortic wall. Selectively deployable external catheter flow control valves suitable for this application are described in commonly owned, copending U.S. patent applications Ser. Nos. 08/665,635, 08/664,361 and 08/664,360, filed Jun. 17, 1996, which are hereby incorporated by reference in their entirety. The elongated catheter shaft  646  may include one or more deployment lumens as needed for actuating the external catheter flow control valve  644 . A cardioplegia lumen, which may also serve as a guidewire lumen, connects to a cardioplegia port  648  at the distal end of the catheter shaft  646 . A perfusion lumen connects to one or more perfusion ports  650  located on the catheter shaft  646  downstream from the external catheter flow control valve  644 , but upstream of the embolic filter assembly  622 . The operation of the perfusion filter catheter  640  of FIG. 16 is quite similar to that described for the embodiment of FIGS.  10 - 14 .  
         [0055]    [0055]FIG. 17 illustrates a seventh embodiment of the present invention having a CEPA capable of being used in combination with many of the features and embodiments previously described. FIG. 17 shows an embodiment of a perfusion filter catheter  660  with a CEPA in the form of an embolic filter assembly  662  having areas of different filter porosity. The embolic filter assembly  662  is mounted on an elongated catheter shaft  666  that can be adapted for peripheral introduction via the femoral artery or subclavian artery or for central insertion directly into the ascending aorta either through a median sternotomy, transternally, thoracotomy or an intercostal space. The embolic filter assembly  662  may resemble any one of the actively or passively deployed embolic filter assemblies described herein. Preferably, the embolic filter assembly  662  assumes one of the surface area increasing geometries described above, such as a trumpet-style embolic filter assembly  662  as shown. The embolic filter assembly  662  is divided along a longitudinal dividing line into areas of different filter porosity. In a preferred embodiment, the embolic filter assembly  662  has an upper portion  664  of finer porosity facing toward the aortic arch vessels and a lower portion  668  of courser porosity facing away from the aortic arch vessels. Preferably, the elongated catheter shaft  666  will have a preformed curve to help orient the upper portion  664  and the lower portion  668  of the embolic filter assembly  662  in the proper position once deployed. The filter mesh of the upper portion  664  may be selected to exclude both macroemboli and microemboli, and the filter mesh of the lower portion  668  may be selected to exclude macroemboli only. Alternatively, the upper portion  664  may be impermeable so as to act like a shunt to direct potential emboli downstream away from the aortic arch vessels.  
         [0056]    Another feature that may be combined with the features and embodiments of the present invention is an aortic transillumination system or infrared emitting means for locating and monitoring the position of the catheter, the filter and the optional occlusion devices without fluoroscopy by transillumination of the aortic wall. Aortic transillumination systems using optical fibers and/or light emitting diodes or lasers suitable for this application are described in commonly owned, copending U.S. patent application Ser. No. 60/088,652, filed Jun. 9, 1998 and its corresponding utility application Ser. No. 09/326,816 filed Jun. 7, 1999, which are hereby incorporated by reference in their entirety.  
         [0057]    FIGS.  18 - 21  illustrate an eighth embodiment of the present invention having a CEPA in the form of an aortic flow divider. The flow divider  810  may be formed in a variety of configurations, however the flow divider  810  in the undeployed state will be contained in a relatively small volume around the circumference of the distal end of the catheter and in the deployed state will have a length and width sufficient to divide blood flow in the aorta in the vicinity of the ostia of the arch vessels. In the undeployed state, the flow divider  810  is collapsible around the catheter shaft creating a low profile not significantly larger than the outer diameter of the catheter body. The flow divider  810  may comprise one or more inflatable chambers, the chambers all being in fluid communication, or one or more selectively deployable shrouds. The inflatable chambers may be relatively non-compliant or they may be compliant, exhibiting elastic behavior after initial inflation, for example, to closely fit the size, shape and curvature of the aortic lumen.  
         [0058]    The catheter may further include one or more additional or auxiliary flow control members located on the catheter either distal or proximal from the flow divider  810  to further segment the patient&#39;s circulatory system for selective perfusion to different organ systems within the body or to assist in anchoring the catheter in a desired position. These auxiliary flow control members may comprise inflatable balloons or selectively deployable external catheter valves as described in connection with to FIGS. 15 and 16. Preferably, the flow divider  810 , and any auxiliary flow control members, or anchoring members, if present, are mounted directly on an elongated catheter shaft. In a preferred embodiment, the catheter shaft includes at least three lumens, one lumen for inflating or otherwise deploying the flow divider  810 , a second for perfusion of the arch vessels, and a third guidewire lumen. In alternate embodiments, additional lumens may be included for deploying the auxiliary flow control members, for measuring the pressure at desired locations within the aorta, or for perfusing other isolated segments of the patient&#39;s circulatory system. Suitable methods and apparatus for performing isolated segmental perfusion for use in conjunction with the present invention are described in commonly owned, copending U.S. patent application Ser. No. 60/084,835 filed May 9, 1998 and its corresponding utility application Ser. No. 09/306,555 filed May 6, 1999, which are hereby incorporated by reference in their entirety.  
         [0059]    The catheter may be configured for retrograde deployment via a peripheral artery, such as the femoral artery, or it may be configured for antegrade deployment via an aortotomy incision or direct puncture in the ascending aorta. The catheter is characterized by a flexible catheter shaft placed by surgical cutdown or Seldinger technique into the vessels of the lower or upper extremity or neck. Other large internal vessels may also be used.  
         [0060]    Anticoagulants, such as heparin and heparinoids, may be applied to the surfaces of the catheter and/or flow control members as desired. Anticoagulants may be painted or sprayed onto the device. Anticoagulants other than heparinoids may also be used, for example monoclonal antibodies such as REOPRO (Eli Lilly and Co., Indianapolis, Ind.). A chemical dip comprising the anticoagulant may also be used. In addition an echogenic coating may also be applied to the catheter to enhance visualization. Other methods known in the art for applying chemicals to catheters may be used.  
         [0061]    [0061]FIG. 18 illustrates the aortic catheter  800  of the present invention having an elongated catheter shaft  802  with a proximal end and a distal end. The proximal end  804  preferably extends out of the patient&#39;s body and the distal end  806  is closest to the patient&#39;s heart. The elongated catheter shaft  802  preferably has an overall length sufficient to reach from the arterial access point to a selected location within a patient&#39;s aorta. For femoral artery deployment in adult human patients, the elongated catheter shaft  802  preferably has an overall length from approximately 60 cm to 120 cm, and more preferably 70 cm to 90 cm.  
         [0062]    In one illustrative embodiment, the elongated catheter shaft  802  has an outer diameter that is preferably approximately 9 to 22 French (3.0 to 7.3 mm), and more preferably 12 to 18 French (4.0 to 6.0 mm) for use in adult human patients. Catheters for pediatric use, or use in non-human subjects, may require different dimensions and would be scaled accordingly. The elongated catheter shaft  802  is preferably formed of a flexible thermoplastic material, a thermoplastic elastomer, or a thermoset elastomer. Suitable materials for use in the elongated catheter shaft  802  include, but are not limited to, polyvinylchloride, polyurethane, polyethylene, polyamides, polyesters, silicone, latex, and alloys or copolymers thereof, as well as braided, coiled or counterwound wire or filament reinforced composites. Additionally or alternatively, the elongated catheter shaft  802  may be constructed using metallic tubing or a solid wire, for example stainless steel hypodermic tubing or wire or superelastic nickel-titanium alloy tubing or wire. Preferably, the aortic catheter  800  includes one or more location markers  816 , such as radiopaque markers and/or sonoreflective markers, to enhance imaging of the aortic catheter  800  during deployment using standard fluoroscopy, ultrasound, MRI, MRA, transesophageal echocardiography, or other techniques. For example, in the illustrative embodiment shown in FIG. 18, a radiopaque location marker  816  is positioned near the distal end  806  of the catheter shaft  802 , and another near the proximal end of the flow divider  810 , to assist in positioning the flow divider  810  within the aortic arch. The radiopaque location markers  816  may be formed as a ring or disk of dense radiopaque metal such as gold, platinum, tantalum, tungsten, or compounds or alloys thereof, or a ring of a polymer or adhesive material heavily loaded with a radiopaque filler material.  
         [0063]    The flow divider  810 , of FIG. 18, is mounted proximate the distal end  806  of the elongated catheter shaft  802 . The embodiment shown in FIGS. 18 through 21, shows the flow divider  810  in the form of a flat elongate expandable inflatable balloon or mattress bonded to the catheter shaft  802  by heat welding or with an adhesive. The inflatable flow divider  810  has a deflated state in which the flow divider  810  adheres closely to the catheter shaft  802  so that the collapsed diameter of the flow divider  810  is, preferably, not substantially larger than the diameter of the catheter shaft  802 , and an inflated state in which the flow divider  810  expands to dimensions sufficient to divide blood flow in the aortic arch of the patient into two fluid flow channels. The distal end of the flow divider may expand beyond the distal end of the catheter as illustrated in FIG. 21 or alternatively may expand to a distance equal to or less than the distal end. Preferably, the flow divider  810  will be formed so that, when inflated, the flow divider  810  automatically assumes and maintains a desired shape, without any additional stiffening structure. However, in some embodiments, it may be desirable to include means for assisting the flow divider  810  in maintaining a desired shape, and any known means for accomplishing this may be used. For example, the divider may include ribs or other stiffening structures coupled to the flow divider  810 , or formed as an integral part of the flow divider  810 . Alternatively, the flow divider  810  may include mattress type welds, or internal welds or columns. The outer surface of flow divider  810  may include a friction increasing means such as a friction increasing coating or texture to increase friction between the flow divider  810  and the aortic wall, to assist in maintaining the flow divider  810  in a desired position within the aorta, when deployed.  
         [0064]    [0064]FIG. 19 is a side view of the catheter  800 , showing that the flow divider  810  is preferably coupled only to a portion of the diameter of the catheter shaft  802 . Thus, perfusion ports  818  are unobstructed. Alternatively, the flow divider may be mounted above the perfusion ports  818  wherein the material covering the ports  818  is skived or cut away to allow for perfusion therethrough. In the inflatable embodiments a heat seal can be created around the skived out area or in the case of mattress type welds the skived area can be in an area of an already existing weld. Furthermore, the material covering the ports  818  may only be partially cut away leaving part of the port covered in order to help facilitate the direction and flow of fluid out the ports  818 . In addition, FIG. 21 illustrates the catheter shaft  802  being substantially centered relative to the divider  810 , alternative embodiments can have the catheter shaft off center, tangential or in any geometric position that helps facilitate placement and optimal flow.  
         [0065]    [0065]FIG. 20 is a cross section of the catheter shaft  802  taken along line  20 - 20  of FIG. 18. The elongated catheter shaft  802  preferably has at least three lumens, an inflation lumen  808  that is used to deploy the flow divider  810 , a perfusion lumen  812  that is used to perfuse one or both of the fluid flow channels, and a guidewire lumen  814 . The configuration of the lumens is shown for illustrative purposes only, and any reasonable configuration of lumens within the catheter may be used. Furthermore, additional perfusion lumens may be added to perfuse both of the fluid flow channels separately and independently. Additional fluid ports similar to ports  818  only positioned in the other fluid flow channel would also be necessary.  
         [0066]    The flow divider  810  is shown in a deployed state in FIG. 21. Preferably, the flow divider  810  in its deployed configuration includes a distal portion  820  that extends beyond the distal end of the catheter  800  in order to seal or touch against the aortic lumen wall. The proximal portion  822  of the divider  810  is shown shaped similarly to the distal portion  820 , however, in this embodiment the shape of the proximal portion  822  of the divider  810  is not critical to the invention and could be triangular, square, or any other desired shape. In other embodiments, it may be preferable that the shape be chosen to encourage low turbulence, or possibly laminar, fluid flow where the fluid flow from the flow channel above the divider  810  and the fluid flow from below the flow divider  810  meet at the trailing edge of the proximal portion  822 . However in a preferred embodiment, the divider is constructed such that any flow around the catheter is directed toward the corporeal circulation and not to the arteries leading to the brain. One preferred method for accomplishing such desirable flow characteristics is to direct any excess flow to the arch around the proximal portion  822  of the divider and down to the corporeal circulation. Such a flow relationship protects the brain by directing any extra flow into the second fluid path and away from the brain. This is also beneficial in that no real seal is necessary, but rather laminar flow is established and emboli are directed away from the divider and the brain by the fluid flow. Even if turbulence results near the trailing edge of the flow divider  810 , embolic material in the blood will have already passed the arch vessels, thereby achieving the objective of preventing embolic material from entering the cerebral circulatory system.  
         [0067]    It may not be essential that the edges of the flow divider  810  create a perfect seal or any seal with the wall of the aorta. Some leakage of blood around the flow divider  810  may be tolerated because the fluid perfused through the perfusion lumen  812  creates a pressure gradient from above the flow divider  810  to below the flow divider  810  so that any potential embolic material will not enter the flow channel above the flow divider  810 .  
         [0068]    Any embodiments of the catheter  800  of the invention described above may further include auxiliary flow control members. The auxiliary flow control members may be used to further compartmentalize the patient&#39;s circulatory system, or may be used for other functions such as assisting in securely anchoring the catheter in a chosen position. An example of a catheter of the invention further comprising an auxiliary flow control member is seen in FIGS. 22 and 23, which illustrate an auxiliary flow control member  830  coupled to the distal end of the catheter  800  proximate the distal end  122  of the flow divider  810 . The auxiliary flow control member  830  is positioned within the aorta and can be fully deployed to occlude or substantially occlude the aorta. The auxiliary flow control member  830  shown in FIG. 22 is an inflatable balloon bonded to the catheter shaft  802  by heat welding or with an adhesive. Alternatively, the auxiliary flow control member  830  could be a deployable valve, or other structure. Deployable valves suitable for use in this application are described in commonly owned U.S. Pat. Nos. 5,827,237 and 5,833,671, which have been previously incorporated by reference. Suitable materials for the inflatable balloon include, but are not limited to, elastomers, thermoplastic elastomers, polyvinylchloride, polyurethane, polyethylene, polyamides, polyesters, silicone, latex, and alloys or copolymers and reinforced composites thereof. In alternate embodiments, the auxiliary flow control member  830  may be positioned on the proximal side of the flow divider  810 , if desired. The auxiliary flow control member  830  may also be used to anchor the catheter  800  so that it does not migrate out of its optimal position during the medical procedure. The outer surface of an auxiliary flow control member  830  used to anchor the catheter  800  may include a friction increasing means, such as a friction increasing coating or texture, to increase friction between the auxiliary flow control member  830  and the aortic wall, when deployed. Alternatively, an auxiliary flow control member  830 , which may be an inflatable balloon or deployable valve, can be mounted on a separate catheter and introduced through a lumen within the catheter  800 .  
         [0069]    [0069]FIGS. 22 and 23 show the flow divider  810  fully deployed, and the auxiliary flow control member  830  partially collapsed and fully deployed. As blood flow resumes from the heart A, embolic material C is diverted away from the arch vessels by the flow divider  810 .  
         [0070]    The previous embodiments have been described using a catheter configured for a retrograde approach to the aorta from a peripheral vessel such as the femoral artery. The invention could easily be modified for alternate deployment means. For example, FIG. 24 shows a catheter  900  configured for central antegrade deployment in the aortic arch through an aortotomy or direct puncture in the ascending aorta. The catheter  900  and flow divider  910  are configured similarly to the catheters disclosed in previous embodiments. Other embodiments of the invention may be configured for peripheral insertion through the subclavian or axillary arteries.  
         [0071]    [0071]FIG. 25 discloses an alternate embodiment of the flow divider  910 , wherein the top surface of the flow divider  910  comprises a mesh or porous region  932 . The perfusion ports  918  allow a selected fluid to enter the interior chamber  934  of the flow divider  910  before the fluid passes through the mesh or porous region  932  to perfuse the aorta. The material or materials used in the flow divider  910  are preferably characterized by properties that allow an internal pressure within the flow divider  910  to be maintained at a sufficient level to maintain the deployed configuration of the flow divider  910  to divide the aorta, while also allowing a controlled volume of fluid to escape from the flow divider  910  through the mesh or porous region  932  on the upper surface of the flow divider  910  for perfusing the arch vessels. Thus, the surface of the flow divider  910  may have porous regions that allow a fluid to be perfused at a known rate when a specific pressure is attained. The inflatable peripheral tube  936  surrounds the periphery of the flow divider  910 , however, in alternate embodiments, this feature may be omitted. In embodiments including an inflatable peripheral tube  936 , it is preferable that the peripheral tube  936  be inflated from a separate additional lumen.  
         [0072]    [0072]FIG. 26 discloses an embodiment of the flow divider  910  of FIG. 25 wherein a single inflation and perfusion lumen may be used. In this embodiment, perfused fluid passes through a lumen  1006  in the shaft  1002  of the catheter  1000  into the peripheral tube  1036  to inflate the peripheral tube  1036 . Apertures  1038  between the inflatable peripheral tube  1036  and the interior chamber  1034  of the flow divider  1010  allow fluid to flow from the peripheral tube  1036  into the chamber  1034  within the inflatable flow divider  1010 . The fluid then passes through the mesh or porous region  1032  of the flow divider  1010  to perfuse the aorta. Preferably, the apertures  1038  of the peripheral tube  1036  are sized so that the pressure within the peripheral tube  1036  is higher than the pressure within the chamber  1034  of the flow divider  1010 .  
         [0073]    The porous and non-porous sections of the flow divider  1010  may be formed from the same or separate materials. Suitable materials for the non-porous portions of the flow divider  1010  include, but are not limited to, elastomers, thermoplastic elastomers, polyvinylchloride, polyurethane, polyethylene, polyamides, polyesters, silicone, latex, and alloys or copolymers, and reinforced composites thereof. Suitable materials for the porous portions of the flow divider  1010  include meshes, woven and nonwoven fabrics, and porous membranes, such as microperforated or laser perforated polymer or elastomer films. For example, polyester meshes may be used, such as meshes made by Saati Corporation and Tetko, Inc. These are available in sheet form and can be easily cut and formed into a desired shape. Other meshes and porous materials known in the art, which have the desired characteristics, are also suitable.  
         [0074]    Referring to FIG. 27, an embodiment of the flow divider  1110  is disclosed having a nonporous film  1140  surrounded by a peripheral tube  1136  acting as a support structure. Inflation of the peripheral tube  1136  causes deployment of the film  1140  within the aorta. Holes are positioned over the perfusion apertures  1118  to allow perfusion of the region above the flow divider  1110 . FIG. 28 is a cross section view of the flow divider  1110  of FIG. 27 taken along line  28 - 28 . It is possible to make the flow divider  1110  of FIG. 27 by fabricating an oval balloon and affixing the central portion of the top and bottom layers together, leaving a peripheral region where the upper and lower layers are not coupled together, forming the inflatable peripheral tube  1136 . Alternatively, the peripheral tube  1136  and film  1140  of the flow divider  1110  may be formed of separate components and affixed together by a known means for joining such materials, such as by heat welding or adhesives.  
         [0075]    FIGS.  29 - 31  represent alternate embodiments of the flow divider  1210  with welds or joined areas between an upper and a lower film of the flow divider  1210  to give additional structure and rigidity to the flow divider  1210 . FIG. 29 discloses an embodiment wherein the interior surface of the upper film has been coupled  1242  to the interior surface of the lower film, preferably by spot heat welding or adhesive. The resulting structure maintains the geometry of the flow divider  1210  and provides it with additional rigidity. FIG. 30 is a cross section view of the flow divider  1210  of FIG. 29 taken along line  30 - 30  of FIG. 29. FIG. 31 shows an alternate embodiment of FIG. 29 with larger joined areas  1342  between the upper and lower films of the flow divider  1310 , creating a well defined peripheral tube  1336  and lateral or branch support members  1344 . In alternative embodiments, the film  1340  and peripheral tube  1336  and lateral or branch support members  1344  maybe fabricated as separate components and joined using any known means for doing so, including the use of adhesive or heat welding.  
         [0076]    All of the previously described flow divider embodiments have been deployed from the external surface of the catheter shaft. However, in other embodiments, the flow divider may be deployed from within one or more lumens in the catheter shaft. For example, FIG. 32 discloses a flow divider  1410  deployed within an aorta B, and coupled to a deployment wire  1470  that is extended from a lumen with an opening in the distal end  1406  of the catheter shaft  1402 . The flow divider  1410  is preferably comprised of a material or materials with a shape memory, so that the flow divider  1410  will assume the desired configuration on release from the catheter shaft  1402 . Any known suitable materials may be used including, but not limited to, elastomers, thermoplastic elastomers, polyvinylchloride, polyurethane, polyethylene, polyamides, polyesters, silicone, latex, and alloys or copolymers, and reinforced composites thereof. In some embodiments, the flow divider  1410  may include lateral or branch stiffeners to assist the flow divider  1410  in maintaining a desired configuration or shape. Perfusion of the arch vessels in this embodiment, may be provided by another perfusion source, such as a second catheter. FIG. 33 is a cross section view of the flow divider  1410  of FIG. 32 taken transversely through the aorta B showing a preferred position of the flow divider  1410  within the aorta B.  
         [0077]    While the present invention has been described herein with respect to the exemplary embodiments and the best mode for practicing the invention, it will be apparent to one of ordinary skill in the art that many modifications, improvements and subcombinations of the various embodiments, adaptations and variations can be made to the invention without departing from the spirit and scope thereof.