Abstract:
A method for removing thrombus or other material from a natural or synthetic body vessel or cavity without the need for direct surgical access. The method includes providing a device supplying high pressure fluid to at least one distal orifice, causing high pressure fluid to emanate from the orifice creating at least one fluid jet, and using the fluid jet to break up material in the vessel. The method further includes directing at least one fluid jet at the opening of an exhaust lumen or target incorporated into the device and using the jet to provide a localized negative pressure which entrains material into the jet for break-up. The method optionally includes using the jet to provide stagnation pressure which drives material along the exhaust lumen. The method optionally includes metering the exhaust to match the fluid input or to be greater or less than the input. A positive displacement pump operating at steady or pulsatile flow provides the high pressure saline to the distal end of the catheter.

Description:
CROSS REFERENCES TO CO-PENDING APPLICATIONS 
     This patent application is a continuation in part application of Ser. No. 08/351,613 filed Dec. 8, 1994, U.S. Pat. No. 6,544,209, which is a divisional application of Ser. No. 07/976,367 filed Nov. 13, 1992, now abandoned, which is a continuation application of Ser. No. 07/563,313 filed Aug. 6, 1990, now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to medical devices and procedures, and more particularly, relates to medical devices and procedures for removing thrombus or other tissue deposits from the cardiovascular system, or from a natural or synthetic tubule or other cavity or synthetic body vessel found in the human body. 
     2. Description of the Prior Art 
     Procedures and apparatus have been developed for ease in removing various tissue. U.S. Pat. No. 4,790,813 issued to Kensey and U.S. Pat. No. 4,842,579 issued to Shiber describe techniques for the removal of plaque deposited in arteries by mechanical ablation using rotating cutting surfaces. These relatively traumatic approaches are directed to the treatment and removal of very hard substances. 
     In current medical procedures, thrombus and other tissue are often removed using a catheter such as is described in U.S. Pat. No. 4,328,811 issued to Fogarty. In this system, a surgical cutdown is performed to access the vessel and allow catheter entry and advancement to a point beyond the deposit. The balloon is inflated and the catheter is withdrawn pulling the tissue along with it. 
     Pressurized fluids have also been used in the past to flush undesirable substances from body cavities. U.S. Pat. No. 1,902,418 describes such a system for domesticated animals. The more modern approaches tend to use vacuum rather than gravity as the primary means for removal of the deposits or tissue and relatively low fluid pressures to cut into and fragment the substances to be removed. 
     U.S. Pat. No. 3,930,505 issued to Wallach describes a surgical apparatus for the removal of tissue from the eye of a patient. As with similar systems, Wallach uses a relatively low pressure Jet of water (i.e. 15 to 3500 psi) to disintegrate the tissue, and a suction pump to perform the actual removal. 
     A similar approach applied to the cardiovascular system is discussed in U.S. Pat. No. 4,690,672 issued to Veltrup. Veltrup also provides a much lower pressure jet of water (i.e., less than 450 psi) to fragment deposits. As with Wallach, Veltrup uses a vacuum pump for evacuation of the fragments. The distal end of the Veltrup catheter is repositionable and requires manual entrapment of the deposits, or else the catheter jet must be moved into contact with the deposit in order to accomplish tissue fragmentation. The vacuum applied by the suction duct holds the tissue at its opening while a jet of water breaks up a solid structure at its mouth. This device is basically a suction tube which requires a vacuum to operate, but contains a distal jet aimed at the distal opening in order to reduce blockage of the opening. 
     SUMMARY OF THE INVENTION 
     The present invention achieves the removal of unwanted thrombus or tissue by utilizing one or more high-pressure fluid jet(s) at the distal end of a catheter to draw the thrombus or tissue towards the catheter and cut or emulsify the thrombus or tissue; the resulting slurry of thrombus or tissue and fluid can then be removed through an exhaust lumen of the catheter, and the fluid jet(s) can provide energy to drive this exhaust. The present invention overcomes the disadvantages of the prior art systems by operating at higher pressures than those envisioned by Veltrup, thereby providing for entrainment of the thrombus or tissue into the fluid jet(s). In addition, the higher pressures produce a force which can be used to drive the fragmented thrombus or tissue out of the catheter without using vacuum. The catheter can draw nearby thrombus or tissue towards the fluid jet(s), which then fragments it without requiring that the catheter be moved into direct contact or juxtaposition with the thrombus or tissue. The high energy of the jet(s) impinging on the opening to the evacuation lumen eliminates the need for a vacuum pump, as the fragmented debris is removed by the evacuation lumen as it is driven out with a driving force above atmospheric pressure. 
     According to the present invention, energy is added to the system via an extremely high pressure stream(s) of liquid, solution, suspension, or other fluid, such as saline solution, which is delivered to the distal end of the catheter via a high pressure tubing, which directs jet(s) of high velocity fluid at the opening of an exhaust lumen. This stream(s) serves to dislodge thrombus or tissue deposits, entrain them into the jet(s), emulsify them, and drive them out of an exhaust lumen. Tissue or debris such as thrombus particles are attracted to the jet(s) due to the localized high velocity and resultant localized low pressure. Recirculation patterns and fluid entrainment bring the thrombus or tissue continually into close proximity of the jet(s). Once emulsified by the jet(s), the thrombus or tissue can be removed through the exhaust lumen by flow generated as a result of stagnation pressure which is induced at the mouth of the exhaust lumen by conversion of kinetic energy to potential energy (i.e., pressure) of at least one fluid jet directed at and impinging on the lumen mouth. The pressure in the high pressure fluid tubing must be great enough to generate a high localized velocity and, hence, a low localized pressure necessary to entrain the surrounding thrombus or tissue. A high enough pressure to generate substantial stagnation pressure at the opening to the exhaust lumen is necessary to drive the exhaust flow. A pressure of at least 500 psi is needed for the high pressure fluid at the distal end, and pressures of over 1000 psi will provide even better entrainment and stagnation pressures. The stagnation pressure formed at the mouth of the exhaust lumen serves to drive the fragmented thrombus or tissue out of the exhaust lumen. This pressure can typically be greater than one atmosphere and, therefore, provides a greater driving force for exhaust than can be accomplished by using a vacuum pump. Additional jets of lower energy may be directed radially outwardly to aid in removal of thrombus or tissue from the vessel wall and provide a recirculation pattern which can bring fragmented thrombus or tissue into contact with the jet(s) impinging on the exhaust lumen opening. 
     The procedure is practiced by percutaneously or intraoperatively entering the vascular system, tubule, or other body cavity of the patient at a convenient location with a cannula. The catheter may be inserted either directly or over a previously positioned guidewire and advanced under fluoroscopy, angioscopy or ultrasound device to the site of the vascular occlusion, obstruction or tissue deposit. The exhaust lumen can permit the passage of an angioplasty dilation catheter, guidewire, angioscope, or intravascular ultrasound catheter for intravascular viewing. The lesion site may contain an aggregation of blood factors and cells, thrombus deposit, or other tissues which are normally identified by angiography or other diagnostic procedure. One or more balloons may be inflated to stabilize the distal end of the catheter and provide a degree of isolation of the area to be treated. An isolation balloon located proximal to the high pressure fluid jet(s) can prohibit fragmented tissues from migrating proximally around the outside of the catheter shaft and immobilizing into a side branch of a blood vessel. An isolation balloon distal to the high pressure fluid jet(s) can prohibit immobilization distally. This may be of greater importance if immobilization of fragmented debris may generate unfavorable clinical sequelae. Thrombolytic drugs such as streptokinase, urokinase, or tPA, and other drugs may be delivered through the catheter along with the saline (or other fluid) or separately to adjunctively aid in the treatment of the lesion. A balloon may also be located at the distal end of the catheter to provide the capability of dilation of the vessel, tubule, or cavity either prior to or following the thrombus or tissue ablation and removal. 
     The catheter described herein is a part of a device in the first embodiment ( FIG. 1 ) which includes a high pressure fluid supply, the fluid being either sterile saline or other suitable physiological solution compatible with the site of catheter operation within the body. The high pressure of the fluid can be generated with a positive displacement pump, such as a piston pump, which can be made to operate with either pulsatile flow or with steady flow. The catheter and the piston pump can be sterile. A nonsterile motor and motor control system can be used to power the piston pump. Sterile saline and physiological solution available to radiological, cardiological and operative sites can be used as a source of fluid from the high pressure positive displacement pump. The high pressure fluid flow from the pump is supplied via a high pressure tube to the distal end of the catheter where at least one jet of fluid is directed toward the opening of an exhaust lumen. A metering device may also be a part of the device which includes the catheter and the high pressure fluid supply. A metering system can be utilized at the proximal end of the exhaust lumen to regulate the flow rate of the fragmented thrombus or tissue out of the catheter. The flow of fragmented thrombus or tissue out of the exhaust lumen can exceed the flow of high pressure fluid from the jet(s) which impinge on its distal opening. As a result, a metering device can be used to reduce the volumetric outflow rate of fragmented thrombus or tissue such that it is equal to, or in balance with, the volumetric rate of high pressure fluid being supplied to the distal end. This balance of flow would then ensure that the fluid volume within a blood vessel, tubule or body cavity is not being significantly altered during the thrombectomy or tissue removal procedure. The outlet flow rate of the thrombus or tissue fragments can also be adjusted such that it is either greater than or less than the high pressure fluid supply rate, in order to either drain or expand the fluid volume within the vessel or cavity. The metering device can be any device with means of measuring the outlet flow rate and adjusting it to a desired magnitude. A roller (peristaltic) pump can be used as a metering device in this application. When used with a specific tubing and rotational speed, prescribed volumetric output of the fragmented thrombus or tissue will be exhausted. 
     A manifold attaches to the proximal end of the catheter to provide leak-free access pathways for the high pressure fluid supply, the exhaust pathway for fragmented thrombus or tissue to be delivered to a collection reservoir, the pathway for fluid (either gas or liquid) for inflation of balloon(s) at the distal end of the catheter (if desired), and the access port for introducing an auxiliary diagnostic or therapeutic device available to the physician. Such therapeutic devices may include a guidewire used to guide the catheter to its appropriate site in a vessel, tubule or cavity. A diagnostic device may include an ultrasound catheter or an angioscope. Contrast agents, thrombolytic drugs, or other drugs may also be delivered to the lesion site either using the exhaust lumen or the high pressure supply tube. A balloon inflation means can be connected to the manifold to deliver a gas or fluid to inflate a balloon(s) located at the distal end of the catheter. Such balloon(s) can serve either to reduce immobilization of fragmented thrombus or tissue or to dilate the lesion. The balloon inflation means can be a sterile syringe or other device available for inflation of angioplasty catheter balloons. 
     According to the second embodiment of the present invention (FIG.  3 ), there is provided a thrombectomy or tissue removal catheter having a manifold at the proximal end and having a distal end which enters percutaneously into a blood vessel, tubule, or cavity of the body in order to fragment thrombus or other tissue obstruction and remove the fragments out of the body. The saline or other high pressure fluid enters the catheter manifold and is routed via a high pressure conduit such as a hypo tube or polyimide tube to the distal end of the catheter where it exits through at least one orifice, which forms one or more jet(s) of high pressure fluid which are directed at the opening of an exhaust lumen. The exhaust lumen carries the fragmented thrombus or tissue from the distal end of the catheter to the manifold which is located outside the body. The high pressure tubing forms a loop at the distal end with the plane of the loop being perpendicular to the axis of the catheter shaft. Holes drilled into the loop form the orifices which direct jets of fluid in a proximal direction back towards the opening of the exhaust lumen. One or more of these jets provides the stagnation pressure at the opening of the exhaust lumen to drive a volumetric outflow of fragmented thrombus or tissue, which can be greater than the flow rate of the high pressure fluid. The stagnation pressure can be higher than one atmosphere, thereby generating a greater exhaust rate than can be accomplished by creating a vacuum at the proximal end of the exhaust lumen with a vacuum pump. The development of a stagnation pressure at the opening of the exhaust lumen requires a pressure within the high pressure tubing at the distal end to be at least 500 psi with improved results occurring with pressures of over 1000 psi. In order to obtain significant entrainment of thrombus or tissue into the high velocity jet(s) as a result of their localized low pressure, it is necessary to operate the device with the pressure of the fluid in the high pressure tubing at the distal end being at least 500 psi. Without high pressure, the amount of entrainment of surrounding tissue or thrombus, which moves into the jet for ablation, is minimal, and the catheter would require direct contact of the jet(s) or juxtaposition with the material to be fragmented. A distal pressure of over 1000 psi for the high pressure fluid provides improved entrainment of thrombus or tissue into the jet(s) for fragmentation. The formation of a loop in the distal portion of the high pressure tubing provides the catheter with the capability of following over a standard guidewire (which then would be located within the loop) while still maintaining unobstructed access to the thrombus or tissue entrained in a jet, as well as access for at least one jet unobstructed by the guidewire to impinge on the exhaust lumen and generate the stagnation pressure to drive thrombus or tissue fragment exhaust. The guidewire can follow through the exhaust lumen of the catheter to efficiently utilize the available space and minimize the diameter of the catheter shaft. The distance between the orifice(s) and the entrance to the exhaust lumen is another important variable in determining the amount of stagnation pressure generated. A distance of one to five millimeters will provide adequate stagnation pressure to drive exhaust, and still provide enough space for thrombus or tissue to become entrained for fragmentation. As this distance becomes greater, there is a tendency towards significantly less stagnation pressure; as the distance becomes smaller, little or no benefit is gained due to limited entrainment. 
     In the third embodiment of the invention (FIG.  8 ), there is provided a thrombus or tissue removal catheter similar in every way to that of the second embodiment except that the orifice(s) are located a further distance away from the opening to the exhaust lumen. At a distance of greater than five millimeters, the jet spray pattern tends to fan out with much of the spray missing the exhaust lumen and also a great loss in its kinetic energy. Even though this device does not generate enough stagnation pressure to drive the exhaust flow, it still will be fully capable of entraining thrombus or tissue into the jet(s) as long as the pressure within the high pressure tubing at the distal end is greater than 500 psi. The catheter, therefore, does not have to be brought into juxtaposition or contact with thrombus or tissue for it to fragment the thrombus or tissue. The localized negative pressure will draw the thrombus or tissue into the jet(s). Exhaust can be accomplished in this case by applying a vacuum or suction as needed. 
     According to the fourth embodiment of the invention (FIG.  9 ), there is provided a catheter similar to that of the second embodiment except with the addition of the following feature which can add to its performance. This device provides additional radially directed jet(s) of fluid to the distal end of the catheter. These additional jet(s) are directed with radial component outwards in order to help dislodge the thrombus or tissues from the blood vessel, tubule, or cavity. The outward jet(s) are of a lower velocity than the jet(s) which direct fluid at the opening of the exhaust lumen. The lower velocity jet(s) will not damage the vessel wall or cause damage to the blood which they may contact. Approximately three jets will clean the perimeter of a vessel or tubule, and will set up a recirculation pattern where the fluid from the radial jets is directed to form a path leading toward the localized low pressure region of the high velocity jet(s) directed at the opening of the exhaust lumen. This recirculation pattern helps to clean the vessel or tubule with greater efficiency. 
     According to the fifth embodiment of the invention (FIG.  14 ), there is provided a catheter similar to that of the first or fourth embodiment except that the following additional features have been added to help performance in specific applications. The catheter shaft tubing can be constructed of plastic with a dual lumen which can provide one lumen for exhaust in a manner similar to the second embodiment and a second lumen for carrying a fluid (either gas or fluid) for inflation of a balloon located on the distal end of the catheter. The balloon can be constructed of latex, silicone, polyurethane, or other elastic material and can serve to center the catheter, as well as isolate the distal end of the catheter so that fragments cannot migrate past the balloon. A balloon of this type could be located either proximal or distal to the fluid jet(s) and exhaust lumen opening or in both locations. A dilation balloon constructed out of polyolefin, polyethylene, polyvinylchloride, polyethylene terephthalate, or other high strength plastic could be similarly located at the distal end of the catheter. Such a balloon could be used to dilate a vessel lesion either before or after the catheter has removed tissue deposits such as thrombus. This catheter contains a separate tubing to carry the high pressure fluid from the manifold to the distal end to supply the high velocity jet(s). 
     According to the sixth embodiment of the invention (FIG.  16 ), there is provided a thrombus or tissue fragmentation catheter that does not remove the fragmented thrombus or tissue. The device contains a high pressure fluid tube such as a hypo tube which delivers high pressure fluid to one or more orifices which direct jet(s) of fluid proximally toward the surface. The surface serves as a target for the jet(s), providing an element of safety to the catheter by prohibiting direct impingement of the jet(s) on the wall of a blood vessel, tubule or duct. The jet(s) have high velocity and low localized pressure due to the high fluid pressure of at least 500 psi in the high pressure tube. Therefore, the jet(s) can both entrain thrombus or tissue onto the jet(s), and break up the tissue or thrombus into fragments. No lumen is available in this catheter for exhaust of the fragments. The impingement surface can be made with an opening, which would allow for guidewire passage, although it is not required. The distal end of the hypo tube can be made into a loop to provide for guidewire passage, although it is not required. Fragments generated by this device can be allowed to remain in the vessel, tubule, or cavity, and may embolize with blood flow, or may be washed out using other means. 
     According to the seventh embodiment of the invention, which applies to previous embodiments that contain an exhaust lumen, there is provided a catheter with a high pressure tube to deliver high pressure fluid from the proximal end of the catheter to the distal end where the fluid is directed by one or more orifices at high velocity onto the distal opening of an exhaust lumen. The pressure in the high pressure tubing at the distal end is at least 500 psi in order to effectively break up the thrombus or tissue deposit. A suction may be applied to the proximal end of the exhaust lumen with a vacuum pump to provide for removal of the fragmented thrombus or tissue, or a roller pump may be used to accomplish a similar effect. The pressure in the high pressure tubing at the distal end may be greater than 500 psi with improved tissue fragmentation occurring at pressures over 1000 psi. Entrainment of tissue such as thrombus into the localized low pressure region of the high velocity jet(s) allows the device to operate effectively without requiring direct contact or juxtaposition of the catheter with neighboring tissue deposit. The distal end of the high pressure tube may form a small arc in order to direct the jet(s) of high pressure fluid proximally toward the opening of the exhaust lumen, or it may form a loop perpendicular to the axis of the catheter shaft in order to direct several jets of fluid rearwards. The loop allows the catheter to follow over a guidewire to reach the lesion site and to effectively fragment thrombus or tissue around the entire perimeter of the guidewire, vessel, tubule, or body cavity. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other objects of the present invention and many of the attendant advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, in which like reference numerals designate like parts throughout the figures thereof and wherein: 
         FIG. 1  is a schematic view of one embodiment of the present invention, a thrombectomy and tissue removal device; 
         FIG. 2  illustrates a cross-sectional view of a manifold; 
         FIG. 3  illustrates a cross-sectional view of a catheter distal end of the present invention; 
         FIG. 4  illustrates an end view of the loop of  FIG. 3 ; 
         FIG. 5  illustrates a cross-sectional view along line  5 — 5  of  FIG. 3 ; 
         FIG. 6  illustrates a cross-sectional view along line  6 — 6  of  FIG. 3 ; 
         FIG. 7  illustrates a cross-sectional view along line  7 — 7  of  FIG. 3 ; 
         FIG. 8 , an alternative embodiment, illustrates a cross-sectional view of another catheter distal end; 
         FIG. 9 , an alternative embodiment, illustrates a cross-sectional view of another catheter distal end; 
         FIG. 10  illustrates a cross-sectional view along line  10 — 10  of FIG.  9  and also  FIG. 14 ; 
         FIG. 11  illustrates a cross-sectional view along line  11 — 11  of FIG.  9  and also  FIG. 14 ; 
         FIG. 12  illustrates a cross-sectional view along line  12 — 12  of FIG.  9  and also  FIG. 14 ; 
         FIG. 13  illustrates a cross-sectional view along line  13 — 13  of FIG.  9  and also  FIG. 14 ; 
         FIG. 14 , an alternative embodiment, illustrates a cross-sectional view of another catheter distal end; 
         FIG. 15  illustrates a cross-sectional view along line  15 — 15  of  FIG. 14 ; 
         FIG. 16 , an alternative embodiment, illustrates a cross-sectional view of another catheter distal end; and, 
         FIG. 17  illustrates an end view of the catheter distal end of FIG.  16 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  is a schematic view of one embodiment of a thrombectomy and tissue removal device  10  according to the present invention. The details supplied herein should be taken as representative and not limiting of the many embodiments which may be efficaciously employed within the scope of the present invention. 
     Thrombectomy and tissue removal device  10  has a two-passage tubular member such as a standard two-lumen catheter  12 , which is extruded of a flexible material such as polyolefin, PTFE, PVC, polyurethane, nylon, or other suitable material in the normal fashion. Near the distal end  16  of catheter  12  can be located inflatable balloon  14 , which is preferably an elastic balloon having no predefined outside diameter size limitation upon inflation. In this manner, balloon  14  can conform to the exact dimensions of the vessel to hold distal end  16  of catheter  12  in a fixed position. Alternatively, inflatable balloon  14  can be an inelastic balloon with a predefined shape and size to permit it to be also used for dilation as in translumenal angioplasty. Distal end  16  of catheter  12  is described in more detail in the figures that follow. Alternatively, the catheter  12  can be made without balloon  14  at all. 
     Guidewire  18  is optionally available for positioning the catheter  12  as an over-the-wire system; or other diagnostic or therapeutic devices can be used along with the catheter, and may occupy the same lumen as occupied by a guidewire  18 . Guidewire  18  passes through the larger of the two lumens of catheter  12  as described in more detail below. 
     A manifold  20  which is molded of a rigid plastic or other suitable material couples to catheter  12 . The main branch of the manifold  20  couples to the larger of the lumens of catheter  12  and has a standard seal assembly  22  applied to the proximal end to sealingly engage the catheter  12 . The guidewire  18  sealingly engages manifold  20  by a standard seal assembly  23 . 
     Secondary branch  24  of manifold  20  is also coupled to the larger lumen to provide for evacuation of the emulsified thrombus deposits. Secondary branch  24  sealingly engages distal end  26  of effluent tubing  28  via seal assembly  30 . 
     The flow of effluent through flexible effluent tubing  28  is metered by rollers  32 ,  34 , and  36  as rotated by rotor  38  in the direction of arrows  40  or any other type of controlled metering structure. It must be emphasized that the effluent in flexible tubing  28  is under pressure and, therefore, need not be pumped by roller (peristaltic) pump  42 , which merely restricts and meters the flow. This metering could equally well be accomplished with a timed mechanical valve (not shown) which controls the outflow rate. After metering, the effluent from flexible effluent tubing  28  is deposited in tissue fragment collection reservoir  44 . 
     Another secondary branch  46  of manifold  20  is sealingly coupled to inflation tube  48  by seal assembly  50 . Inflation and deflation of inflatable balloon  14  is controlled by balloon inflation fluid means  52  in the customary manner. 
     The solution used to emulsify the thrombus deposit is derived from the standard sterile fluid (e.g., saline) container  54 , which may be commercially available. The saline or other solution is transferred to the high pressure supply means  56  via tubing and coupling assembly  58 . This is a low pressure fluid path. 
     The high pressure supply means  56  can be a positive displacement piston pump  59 . It is made to be completely disposable for sanitary reasons. The pump  59  can operate under pulsatile or steady flow. 
     The high pressure output of disposable pump  59  is coupled by a high pressure fluid tube  60  of the catheter by a connection  62  made at another secondary branch  62  of the manifold  20 . 
       FIG. 2  is a cross-sectional view of manifold  20  which includes the proximal end of the flexible two-lumen catheter  12 . This component can be molded as two halves, which are solvent-bonded together, this view showing one of the two possible halves. As described above, catheter  12  is a two-lumen catheter. In the preferred mode, each of the two lumens has two distinct functions. Therefore, manifold  20  serves to provide passage for a high pressure tubing and balloon inflation through one lumen and passage of a guidewire and evacuation through the other lumen. 
     The larger lumen of catheter  12  is lumen  64 . It is used for passage of guidewire  18  (not shown in this view) and for evacuation of effluent and possible passage of a therapeutic angioplasty dilatation catheter, dilatation guidewire, angioscopic probe, or other therapeutic or diagnostic device. Lumen  64  extends through manifold  20  to the proximal end of the manifold and provides passage of a guidewire or other diagnostic or therapeutic device. Guidewire  18  is sealed by compressible circular seal  66  which is compressed by surface  68  as threaded knob  70  is tightened on threads  72 . It is important to seal guidewire  18  in this way as guidewire  18  must be movable with respect to catheter  12  to properly manipulate distal end  16  of catheter  12  into position. 
     Lumen  64  is also terminated at secondary branch  24 . This is accomplished by removing a portion of the outer wall of lumen  64  at point  74 . This provides fluid coupling between lumen  64  and lumen  76  of secondary branch  24 . 
     The smaller lumen of catheter  12  is lumen  78 . One of its functions is as a fluid passageway for the inflation of balloon  14 . This function is accomplished by removing a portion of the outer wall of lumen  78  at point  80  to fluid couple lumen  78  to lumen  82  of secondary branch  46 . 
     The remaining purpose of lumen  78  is to provide for passage of metallic tubing  84 . Because of the extremely high pressures involved, the saline or other solution is conveyed in a metallic tubing  84 , which is preferably stainless steel hypo tubing. To handle the pressures involved, the hypo tubing is run as a continuous length along catheter  12 . The proximal end of metallic tubing  84  passes through the outer wall of lumen  78  at point  89  and into secondary branch  62 . A larger diameter hypo tube  60  is brazed onto hypo tube  84  at point  86 . Alternatively, the larger diameter hypo tube  60  may be attached to hypo tube  84  with a removable connection. This larger tubing  60  is covered by protective plastic tubing  88 . Manifold  20  is solvent-bonded together prior to assembly of the catheter, and points  90 ,  91 ,  92 ,  93  and  94  are used to introduce an adhesive which serves as a seal to separate each path and each lumen. Point  95  shows the bonding of the outer plastic tubing  88  which surrounds the high pressure supply tube  60  to the manifold. 
       FIG. 3  illustrates a cross-sectional view of catheter distal end  16  including an outer plastic sheath  102 , a tip  104  having a large external orifice  106 , a septum  108  encompassing a hypo tube  110  and holding it to the inner surface of the outer plastic sheath  102 , and an evacuation lumen  112  incorporating the large external orifice  106  and further formed by the inner surface of the outer plastic sheath  102  and the septum  108 . A loop  114  is located at the distal end of the hypo tube  110 . The loop  114  allows the catheter to follow easily over a guidewire, but the distal end of the hypo tube is not required to be looped. Orifices  116 ,  118  and  120  serve to direct jets  124  of fluid (e.g., saline) into the external orifice  106  which communicates with the evacuation lumen  112 . 
     The fluid jets  124  are directed out of the orifices  116 ,  118  and  120  in the loop  114  and back toward the external orifice  106  to the evacuation lumen  112 . A beveled surface  126  is included on the outer portion of the tip  104  to help direct fluid flow to the evacuation lumen  112 . There are no fluid jets shooting in an outward direction. Since some blood vessels and tubules are smaller in diameter, one does not require outward shooting fluid jets. Also, the absence of outward shooting fluid jets makes this design safe with low risk of vessel damage or spasm. The simplicity of the design allows the device to be made with a small diameter at the tip (i.e., 4F or 0.052″). The catheter can be made with diameters ranging from 2F to 10F (0.026 ″-0.130″) or larger if desired. The loop  114  in the hypo tube  110  still allows the device to follow a guidewire without causing damage to the vessel. More than three orifices could be used with some tradeoffs of advantages and disadvantages, but this will not offer much advantage. More orifices of the same size will result in a greater effluent flow rate to be removed due to the additional fluid jets. More orifices of a smaller diameter will result in a greater chance of plugging and a lower penetration distance capability for the jetted fluid in order to maintain the total jet flow rate at an appropriate level. If the total jet flow rate becomes too large, the pressure energy loss in the high pressure tube becomes very large and requires excessive liquid pressure at the proximal end of the high pressure tube. Two fluid jets could be used instead of three, but the ability of the catheter to clean around the entire vessel perimeter becomes hampered. A single fluid jet does not work well when a guidewire is in place since the guidewire blocks entry of thrombus. Also, a loop is very helpful to allow the catheter to track closely over a guidewire without inducing trauma to the vessel. 
     This catheter when operated with a distal pressure in the high pressure lumen of at least 500 psi will entrain thrombus or tissue deposit into the one or more proximally shooting fluid jet(s)  124  before it reaches the external orifice  106  to the evacuation lumen  112 . If the distance from the orifice(s) to the external orifice  106  of the evacuation lumen is relatively close, such as 1-5 mm with an average distance of approximately 3 mm, the fluid jet(s) will generate a stagnation pressure at the orifices which can exceed 1 atmosphere, and will drive the evacuation of the fragmented tissue out of the evacuation lumen  112  without the need for a vacuum pump or any application of suction. Instead, a metering means, such as that of  FIG. 1 , can be applied to the proximal end of the evacuation lumen  112  to control the rate of evacuation as desired. The roller (peristaltic) pump  42  of  FIG. 1  can serve as this metering means to control the rate of evacuation such that it is greater than, equal to, or less than the flow rate of fluid exiting the orifices at the distal end of the high pressure tube  110 . 
       FIG. 4  illustrates an end view of the loop  114 , where all numerals correspond to those elements previously described. 
       FIG. 5  illustrates a cross-sectional view along line  5 — 5  of  FIG. 3  illustrating the orifices  116 ,  118  and  120 , where all other numerals correspond to those elements previously described. 
       FIG. 6  illustrates a cross-sectional view along line  6 — 6  of  FIG. 3  illustrating the exhaust lumen  112  in the area of the tip  104 . All other numerals correspond to those elements previously described. 
       FIG. 7  illustrates a cross-sectional view along line  7 — 7  of  FIG. 3  illustrating the exhaust lumen  112  in the distal area of the catheter  12 . All other numerals correspond to those elements previously described. 
       FIG. 8  illustrates a cross-sectional view of a catheter distal end  130  having like and similar component members to the catheter distal end  16  of  FIG. 3  with the exception that the hypo tube now labeled  132  extends a greater distance past the tip member  104 . All other numerals correspond to those elements previously described. 
     If the distance from the orifices  116 ,  118  and  120  to the opening  106  of the evacuation lumen  112  is large, such as greater than 5 mm, the catheter will loose much of the stagnation pressure formed from the impingement of the fluid jets  124  on the opening to the evacuation lumen  112 . Suction may be applied to the proximal end of the evacuation lumen to provide for removal of fragmented tissue. The device, however, will still entrain thrombus or tissue deposit into the localized low pressure region of the fluid jets  124  as long as the pressure at the distal end of the high pressure tubing is at least 500 psi. 
       FIG. 9  illustrates a cross-sectional view of an alternative embodiment of a catheter distal end  200  that is similar to that illustrated in  FIG. 3  except that this catheter distal end  200  has been modified to provide for fluid jets with a component directed radially outwardly of a lower energy than the proximally shooting fluid jets which impinge on the opening of the evacuation lumen. The distal end  200  is comprised of an outer plastic sheath  202 , a manifolded tip  204  having an inner manifolded tip member  206  and an outer tip member  208  aligned over and about the inner manifolded tip member  206 , a large external orifice  210 , a septum  212  encompassing a hypo tube  214  and holding it to the inner surface of the outer plastic sheath  202 , and an effluent evacuation lumen  216  incorporating the large external orifice  210  and further formed by the inner surface of the outer plastic sheath  202  and the septum  212 . A loop  218  is located at the distal end of the hypo tube  214 . The loop  218  allows the catheter to follow easily over a guidewire, but the distal end of the hypo tube is not required to be looped. Orifices  220 ,  222  and  224  (see  FIG. 10 ) serve to direct jets  234  of fluid (e.g., saline) into the large external orifice  210  which communicates with effluent evacuation lumen  216 . 
     The manifolded tip  204  of the distal catheter end  200 , which has been modified to include both an inner manifolded tip member  206  and an outer tip member  208 , provides a three stage manifolded tip  204  for reducing the pressure delivered to three radially outwardly directed orifices  226 ,  228  and  230  illustrated in  FIG. 13  which serve to produce radially outwardly directed or outwardly facing fluid jets  250 ,  251  and  252 . This reduction in pressure provides for a lower velocity for these fluid jets and, consequently, these radially outwardly directed fluid jets  250 ,  251 , and  252  are less traumatic than the rearwardly shooting fluid jets  234 . The radially outwardly directed fluid jets  250 ,  251  and  252  help to clean thrombus or tissue deposit from the walls of blood vessels or tubules and bring the deposit into the rearwardly directed fluid jets  234  for fragmentation and removal. 
     The saline or high pressure liquid enters the proximal end of the high pressure hypo tube  214  and flows to the distal end of the high pressure hypo tube  214 . Some of the liquid flows out of an opening  232  in the high pressure tube  214  into the first manifold space  236  and successive spaces  238  and  240  of the manifolded tip  204 , and some liquid flows out of the orifices  220 ,  222  and  224  which direct the fluid jets  234  backwards toward the external orifice  210  to the effluent evacuation lumen  216 . The fluid which enters the manifolded tip  204  still may possess significant localized kinetic energy which requires dissipation. As shown in this figure, the liquid is directed from the opening  232  and thence through the three stages of the manifolded tip  204  (i.e., three manifold spaces  236 ,  238  and  240  with flow resistance narrowings  242 ,  244 ,  246  and  248  between them as illustrated in  FIGS. 11 and 12 . The liquid is then expelled radially through the three exit side orifices  226 ,  228  and  230  of  FIG. 13  with low velocity. Various manifold arrangements could be used to dissipate the kinetic and potential energy of the liquid prior to expelling the stream out of the catheter distal end. 
       FIG. 10  illustrates a cross-sectional view along line  10 — 10  of  FIG. 9 , where all numerals correspond to those elements previously described. 
       FIG. 11  illustrates a cross-sectional view along line  11 — 11  of  FIG. 9  showing a flow resistance narrowing  242  leading from the manifold space  236  to the manifold space  238  of FIG.  12 . All other numerals correspond to those elements previously described. 
       FIG. 12  illustrates a cross-sectional view along line  12 — 12  of  FIG. 9  showing flow resistance narrowings  244 ,  246  and  248  between the manifold space  238  and the manifold space  240  of FIG.  13 . All other numerals correspond to those elements previously described. 
       FIG. 13  illustrates a cross-sectional view along line  13 — 13  of  FIG. 9  showing the manifold space  240  and the radially outwardly directed orifices  226 ,  228  and  230  in the walls of the outer tip member  208 . All other numerals correspond to those elements previously described. 
       FIG. 14  illustrates a cross-sectional view of a catheter distal end  300  similar to that illustrated in  FIG. 9  except that a balloon  219  has been added to the outer plastic sheath  202  proximal to the orifices  220 ,  222  and  224 . The addition of a balloon is accomplished on this or any other catheter end so identified to contain a lumen which can carry a fluid (either gas or liquid) from the proximal end of the catheter to a more distal location in approximation with a balloon. The outer plastic sheath  202  is constructed of a dual-lumen plastic construction where the balloon inflation lumen  213  (see  FIG. 15 ) is the portion between the inner surface of the septum  212  and the outer plastic sheath  202 . The high pressure hypo tubing  214  aligns in and utilizes the same balloon inflation lumen  213  for efficiency. The balloon  219  secures by adhesives  217  over and about the outer plastic sheath  202  and is inflated through an inflation port  215  connected to the balloon inflation lumen  213  (see FIG.  15 ). All other numerals correspond to those elements previously described. 
       FIG. 15  illustrates a cross-sectional view along line  15 — 15  of  FIG. 14 , where all numerals correspond to those elements previously described. Illustrated in particular is the balloon inflation lumen  213  and the balloon inflation port  215 . 
       FIG. 16  illustrates a cross-sectional view of a catheter distal end  400  having a high pressure hypo tube  402  such as a metal hypo tube, polyamide tube or other high pressure tube which provides a pathway for saline or other high pressure liquid from the proximal end to the distal end of the catheter. The saline exits through one or more orifices  404 ,  406  or  408  (see  FIG. 17 ) in the loop  410  and the high velocity jet streams  412  produced at orifices  404 ,  406  and  408  impinge upon the impingement surface  414  of a target body  416 . The high velocity of the jet streams  412  provides a localized low pressure which serves to draw thrombus or other tissue deposits into the jet streams  412  where it is fragmented into small pieces which will continue to get smaller as they are reintroduced into the high velocity jet streams  412 . The impingement surface  414  provides a safety aspect to the catheter by prohibiting the jet streams  412  from coming into juxtaposition with the vessel cavity wall and causing unwanted trauma to healthy tissues. The target body  416  can be made as shown with a lumen  418  to allow for this catheter to pass over a standard guidewire in order to reach the lesion site in the blood vessel, tubule, or body cavity. The device can consist of only one high velocity jet stream with the impingement surface made smaller in surface area, or it can have up to ten jet streams. The preferred number of jet streams is three in order to clean thrombus around all sides of the vessel or tubule when a guidewire is in place. The device can be made without a guidewire lumen if desired. This device operates with a pressure in the distal end of the high pressure tube of at least 500 psi and preferably 1000-2000 psi. The high tube pressure is necessary to generate the large localized negative pressure at the jet streams required to provide for entrainment of thrombus or tissue deposit into the jet streams. A plastic protective covering  420  may be used to provide resistance to vessel trauma and aligns over and about the hypo tube  402 . 
       FIG. 17  illustrates an end view of the catheter distal end  400 , where all numerals correspond to those elements previously described. 
     Various modifications can be made to the present invention without departing from the apparent scope hereof. 
       FIG. 1  illustrates a representative example of various components of the catheter in the device for tissue removal according to the present invention. Particular embodiments of the present invention may not require all elements shown in FIG.  1 . For example, the catheters shown in  FIGS. 3 ,  8 ,  9  and  16  do not contain a balloon and do not require inflation tube  48  and inflation fluid means  52 . Similarly, the catheter shown in  FIG. 16  does not provide for removal of debris and does not require effluent tubing  28 , peristaltic pump  42 , or tissue fragment collection reservoir  44 . 
     
       
         
               
             
               
               
             
           
               
                   
               
               
                 THROMBECTOMY AND TISSUE REMOVAL METHOD 
               
               
                 PARTS LIST 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 10 
                 thrombectomy and tissue removal device 
               
               
                 12 
                 two-lumen catheter or two-passage tubular member 
               
               
                 14 
                 balloon 
               
               
                 16 
                 catheter distal end 
               
               
                 18 
                 guidewire 
               
               
                 20 
                 manifold 
               
               
                 22 
                 seal assembly 
               
               
                 23 
                 seal assembly 
               
               
                 24 
                 secondary branch 
               
               
                 26 
                 distal end 
               
               
                 28 
                 effluent tubing 
               
               
                 30 
                 seal assembly 
               
               
                 32 
                 roller 
               
               
                 34 
                 roller 
               
               
                 36 
                 roller 
               
               
                 38 
                 rotor 
               
               
                 40 
                 arrows 
               
               
                 42 
                 roller (peristaltic) pump 
               
               
                 44 
                 collection reservoir 
               
               
                 46 
                 secondary branch 
               
               
                 48 
                 inflation tube 
               
               
                 50 
                 seal assembly 
               
               
                 52 
                 inflation fluid means 
               
               
                 54 
                 sterile fluid container 
               
               
                 56 
                 high pressure supply means 
               
               
                 58 
                 tubing and coupling assembly 
               
               
                 59 
                 pump 
               
               
                 60 
                 high pressure fluid tube 
               
               
                 62 
                 secondary branch 
               
               
                 64 
                 lumen 
               
               
                 66 
                 compressible seal 
               
               
                 68 
                 surface 
               
               
                 70 
                 threaded knob 
               
               
                 72 
                 threads 
               
               
                 74 
                 point 
               
               
                 76 
                 lumen 
               
               
                 78 
                 lumen 
               
               
                 80 
                 point 
               
               
                 82 
                 lumen 
               
               
                 84 
                 metallic tubing or hypo tube 
               
               
                 86 
                 point 
               
               
                 88 
                 plastic tubing 
               
               
                 89 
                 point 
               
               
                 90 
                 point 
               
               
                 91 
                 point 
               
               
                 92 
                 point 
               
               
                 93 
                 point 
               
               
                 94 
                 point 
               
               
                 95 
                 point 
               
               
                 102 
                 plastic sheath 
               
               
                 104 
                 tip 
               
               
                 106 
                 external orifice 
               
               
                 108 
                 septum 
               
               
                 110 
                 hypo tube 
               
               
                 112 
                 exhaust lumen or evacuation lumen 
               
               
                 114 
                 loop 
               
               
                 116 
                 orifice 
               
               
                 118 
                 orifice 
               
               
                 120 
                 orifice 
               
               
                 124 
                 fluid jet 
               
               
                 126 
                 beveled surface 
               
               
                 130 
                 catheter distal end 
               
               
                 132 
                 hypo tube 
               
               
                 200 
                 catheter distal end 
               
               
                 202 
                 outer plastic sheath 
               
               
                 204 
                 manifolded tip 
               
               
                 206 
                 inner manifold tip member 
               
               
                 208 
                 outer tip member 
               
               
                 210 
                 external orifice 
               
               
                 212 
                 septum 
               
               
                 213 
                 balloon inflation lumen 
               
               
                 214 
                 hypo tube 
               
               
                 215 
                 inflation port 
               
               
                 216 
                 effluent evacuation lumen 
               
               
                 217 
                 adhesive 
               
               
                 218 
                 loop 
               
               
                 219 
                 balloon 
               
               
                 220 
                 orifice 
               
               
                 222 
                 orifice 
               
               
                 224 
                 orifice 
               
               
                 226 
                 radially outwardly directed orifice 
               
               
                 228 
                 radially outwardly directed orifice 
               
               
                 230 
                 radially outwardly directed orifice 
               
               
                 232 
                 opening 
               
               
                 234 
                 fluid jet 
               
               
                 236 
                 manifold space 
               
               
                 238 
                 manifold space 
               
               
                 240 
                 manifold space 
               
               
                 242 
                 flow resistance narrowing 
               
               
                 244 
                 flow resistance narrowing 
               
               
                 246 
                 flow resistance narrowing 
               
               
                 248 
                 flow resistance narrowing 
               
               
                 250 
                 radially outwardly directed fluid jet 
               
               
                 251 
                 radially outwardly directed fluid jet 
               
               
                 252 
                 radially outwardly directed fluid jet 
               
               
                 300 
                 catheter distal end 
               
               
                 400 
                 catheter distal end 
               
               
                 402 
                 hypo tube 
               
               
                 404 
                 orifice 
               
               
                 406 
                 orifice 
               
               
                 408 
                 orifice 
               
               
                 410 
                 loop 
               
               
                 412 
                 high velocity jet stream 
               
               
                 414 
                 impingement surface 
               
               
                 416 
                 target body 
               
               
                 418 
                 lumen 
               
               
                 420 
                 plastic covering