Rheolytic thrombectomy catheter

Abstract: A rheolytic thrombectomy catheter and method of using same to remove thrombus from a body vessel or other body cavity. Several embodiments are disclosed. All embodiments include an outer catheter having a lumen and an inner high pressure tube of a size to enable it to be passed through the lumen of the catheter. The distal end of the inner high pressure tube extends beyond the distal end of the catheter and carries a jet cap for directing one or more jets of saline proximally toward the distal end of the catheter. In some embodiments, the catheter has a distally located inwardly directed stationary stop and the inner high pressure tube includes a distally located outwardly directed transitional stop for engaging the inwardly directed stationary stop to thereby position the jet cap at a defined distance from the distal end of the catheter. In other embodiments, a stationary stop is located at the proximal end of the catheter and a transitional stop is carried on the proximal end of the inner high pressure tube. In the embodiments having the stationary and transitional stops located proximally, the inner high pressure tube includes a flow director at its distal end. In use, thrombus is dislodged, entrained, and broken into pieces by the saline jets and evacuated proximally through the lumen of the catheter.

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention - The present invention relates to a rheolytic thrombectomy catheter and method of using same to remove thrombus from a body vessel or other body cavity. 2. Description of the Prior Art - Procedures and apparatus have been developed for ease in removing tissue and various deposits. Several such devices employ a jet of saline as the working tool to help break up the tissue deposit and further provide a suction means to remove the deposit. U.S. Pat. No. 5,135,482 to Neracher describes a hydrodynamic device for removal of organic deposit from a human vessel. A supply of saline is delivered by a high pressure duct to the distal end of a catheter. The saline exits the duct as a jet that is directed generally forward and directly toward the tissue to be broken up. The duct is contained within and can move axially with respect to a hose that is positioned around the duct. A vacuum suction is applied to the hose to remove the debris that is created from the broken-up tissue. This device is not intended to pass through tortuous pathways found in the fragile vessels of the brain, and any attempt to employ the device for such purpose would be far too traumatic to the patient. Another drainage catheter, described by Griep in U.S. Pat. No. 5,320,599, has a discharge channel and a pressure channel. The channels are formed into a single catheter tube such that the two tubes are fixed with respect to each other. This catheter could not provide the flexibility needed to negotiate the tortuous vascular pathways found in the vessels of the brain. EP 0 934 729 A discloses a rheolytic thrombectomy catheter according to the preamble of claim 1. SUMMARY OF THE INVENTION The general purpose of the present invention is to provide a rheolytic thrombectomy catheter to remove thrombus from a body vessel or other body cavity. Accordingly, the present invention provides a rheolytic thrombectomy catheter (310) for the removal of thrombus from a body vessel or other body cavity, said catheter having an evacuation tube (332) containing a longitudinally positionable high pressure hypo-tube (334) with a jet cap (350) at the distal end (348) thereof for directing a solution backwards towards the distal end (333) of the evacuation tube (332); characterised in that the catheter includes: a. an exhaust tube portion (342), affixed to said hypo-tube (334); b. said exhaust tube portion (342) permitting rotational and longitudinal movement of said hypo-tube (334) relative to said evacuation tube (332) and said exhaust tube portion (342) overlapping (Fig. 27) a portion of said evacuation tube (332) at said distal end (333) thereof and said exhaust tube portion (342) extending distal (Fig. 27) of the distal end (333) of said evacuation tube (332); and c. said hypo-tube (334) and said exhaust tube portion (342) being separable from said evacuation tube (332). Preferred embodiments are described in the sub-claims. Preferably, the rheolytic thrombectomy catheter has a guidewire coil attached at the distal end of the jet cap to allow advancement of the inner assembly and the outer assembly together within the vasculature. Preferably, the rheolytic thrombectomy catheter has a jet cap which directs a jet of saline toward the distal end of the catheter, which functions as an evacuation tube. Preferably, the rheolytic thrombectomy catheter includes a high pressure hypo-tube with at least one orifice and a jet cap configured and arranged for directing one or more jets of saline to impinge upon or near the distal end of the catheter. The rheolytic thrombectomy catheter preferably is flexible and can pass over a standard guidewire through tortuous vascular pathways. A method of removing thrombus from an obstructed body vessel, which does not form part of the invention, using the apparatus of the preferred embodyment includes the steps of: a. providing a guidewire and an outer assembly including a catheter having an interior annular surface, a distal end, and an externally located stationary hemostasis nut/stop positioned adjacent to the proximal end; b. advancing the guidewire to a vascular site containing thrombus; c. advancing the catheter over the guidewire to the vascular site containing thrombus to position the distal end at the vascular site; d. removing the guidewire from the catheter; e. providing an inner assembly including a hypo-tube carrying a jet cap at its distal end, a flow director including an expandable exhaust tube proximal of the jet cap, and a transitional filter housing/high pressure connection/stop assembly at its proximal end; f. advancing the inner assembly to a desired position within the catheter of the outer assembly, so that a gap proximal to the jet cap extends past the distal end of the catheter; g. providing a high pressure saline supply to the hypo-tube so as to cause a jet of saline to emanate from the jet cap and to entrain thrombus into a gap or space where the thrombus is macerated and then pushed into the catheter for removal from the body; and, h. providing impingement of the jet on the evacuation lumen to create sufficient stagnation pressure to allow evacuation of debris with no need for additional suction on the proximal end of the evacuation lumen. In the method, preferably, the jet cap carries a distally projecting guidewire coil to facilitate further distal advancement of the inner assembly and the outer assembly together or independently within the vasculature to a further vascular site containing thrombus so as to remove additional distally situated thrombus. One significant aspect and feature of the present invention is the variously designed jet caps which are oriented to direct jets of saline in a proximal direction. A further significant aspect and feature of the present invention is the guidewire coil provided at the distal end of the jet cap to allow advancement of the inner assembly and the outer assembly together or independently within the vasculature. There is also provided other significant aspects and features (not forming part) of the present invention including the use of a transitional filter housing/high pressure connection/stop assembly proximally located on the inner assembly and a atationary hemostasis nut/stop proximally located on the outer assembly to prevent the inner assembly from being excessively advanced, so that the expandable tube proximal end does not become disengaged from the distal end of the catheter. A further significant aspect and feature, but which does not form part of the invention is an annulus which is open for lateral movement of the inner assembly within the outer assembly during the initial unpressurized mode (insertion) and which is closed and sealed by jetted saline during the ablation process to provide maximum proximally directed saline flow without leakage between the outer and inner assemblies when thrombotic tissue is broken up and carried proximally. Having thus described embodiments and significant aspects and features of the present invention, it is the principal object of the present invention to provide a rheolytic thrombectomy catheter to remove thrombus from a body vessel. One object of the present invention is to provide a rheolytic thrombectomy catheter of such size, flexibility and construction as to enable it to pass readily through the tortuous pathways found in the fragile vessels of the brain. Another object of the present invention is to provide a rheolytic thrombectomy catheter with means for producing one or more jets of saline and projecting them in a proximal direction toward a site of thrombus and toward an evacuation passage. Yet another object of the present invention is to provide a rheolytic thrombectomy catheter with means for producing one or more jets of saline and with indexing means to position the jet producing means at a prescribed location at the distal end of the catheter. Still another object of the present invention is to provide a rheolytic thrombectomy catheter of the type having an inner assembly that is insertable into an outer assembly with stop means for limiting the extent to which the inner assembly can be inserted into the outer assembly. A further object of the present invention is to provide a rheolytic thrombectomy catheter of the type having an inner assembly and an outer assembly with means which centers the inner assembly within the outer assembly and which orients the parts of the inner assembly in a prescribed manner with respect to the parts of the outer assembly. 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. The embodiments of Figures 1 to 23 do not form part of the invention but represent background art useful in understanding the invention. In the drawings: FIG. 1 is a side view of a rheolytic thrombectomy catheter useful for the removal of thrombus; FIG. 2 is a semi-exploded side view of the rheolytic thrombectomy catheter depicting the two major assemblies thereof, viz., an outer assembly and an inner assembly; FIG. 3 is a semi-exploded cross sectional side view of a manifold and adjacent components constituting parts of the outer assembly; FIG. 4 is a longitudinal sectional view of a filter housing/high pressure connection assembly attached to the proximal end of a hypo-tube, shown only partially; FIG. 5 is a side view of a transitional stop, a jet cap, and a guidewire coil aligned over and about the hypo-tube at the distal end thereof; FIG. 6 is an isometric view of the transitional stop; FIG. 7 is a longitudinal sectional view taken along line 7-7 of FIG. 5; FIG. 8 is a view of the proximal end of the jet cap on the hypo-tube looking in the direction of line 8-8 of FIG. 7, with the hypo-tube shown in cross section; FIG. 9 is a view similar to FIG. 8 illustrating a slightly modified version of the jet cap; FIG. 10 is a longitudinal sectional view of the catheter distal end taken along line 10-10 of FIG. 2; FIG. 11 is a longitudinal sectional view of the catheter distal end with the transitory stop, the jet cap, and the guidewire coil on the hypo-tube shown advancing therethrough; FIG. 12 is a longitudinal sectional view of the catheter distal end with the transitory stop, the jet cap, and the guidewire coil on the hypo-tube shown in final advanced position; FIG. 13 is a cross-sectional view taken along line 13-13 of FIG. 12; FIG. 14 is presented to illustrate schematically the mode of operation of the rheolytic thrombectomy catheter, and is a longitudinal sectional view depicting the distal end of the rheolytic thrombectomy catheter within a blood vessel at the site of a thrombotic deposit and lesion; FIG. 15 is a longitudinal sectional view similar to FIG. 7 but illustrating an alternative jet cap embodiment; FIG. 16 is a view of the proximal end of the alternative jet cap embodiment shown in FIG. 15 looking in the direction of line 16-16 of FIG. 15 , with the hypo-tube shown in cross section; FIG. 17 is a longitudinal sectional view similar to FIG. 15 but illustrating another alternative jet cap embodiment; FIG. 18 is a view of the proximal end of the alternative jet cap embodiment shown in FIG. 17 looking in the direction of line 18-18 of FIG. 17, with the hypo-tube shown in cross-section; FIG. 19 is a longitudinal sectional view similar to FIG. 12 but illustrating an alternative transitional stop embodiment; FIG. 20 is a view of the catheter distal end looking in the direction of line 20-20 of FIG. 19, with the hypo-tube shown in cross section; FIG. 21 is a view similar to FIG. 12 but illustrating alternative embodiments of the transitional stop and the stationary stop; FIG. 22 is a view of the catheter distal end looking in the direction of line 22-22 of FIG. 21, with the hypo-tube shown in cross section; FIG. 23 is a side view in partial cross section of a fifth alternative embodiment of the catheter distal end, where the hypo-tube is fixed along the longitudinal axis of the catheter; FIGURES 24 to 35 relate to a preferred embodiment of the present invention. FIG. 24 is a side view of the preferred embodiment of the rheolytic thrombectomy catheter; FIG. 25 is a semi-exploded side view of the rheolytic thrombectomy catheter of FIG. 24; FIG. 26 is a longitudinal sectional view of the filter housing/high pressure connection/stop assembly located at the proximal end of the hypo-tube of the preferred embodiment; FIG. 27 is an isometric view of the flow director, the jet cap and the guidewire coil of the preferred embodiment; FIG. 28 is an exploded isometric view of the flow director, the jet cap, and the guidewire coil shown in FIG. 27; FIG. 29 is a view in cross section of the flow director, the jet cap and the guidewire coil along line 29-29 of FIG. 24 in the unpressurized mode; FIG. 30 is a view in cross section of the flow director, the jet cap and the guidewire coil along line 29-29 of FIG. 24 in the pressurized mode; FIG. 31 is a view in cross section of the jet cap and the guidewire coil along line 31-31 of FIG. 27; FIG. 32 is a view in cross section of the junction of the inner body and the expandable exhaust tube along line 32-32 of FIG. 30 ; FIG. 33 is a view in cross section of the distal end of the rheolytic thrombectomy catheter along line 33-33 of FIG. 29 in the unpressurized mode; FIG. 34 is a view in cross section of the distal end of the rheolytic thrombectomy catheter along line 34-34 of FIG. 30 in the pressurized mode; and, FIG. 35 is a view in cross section and in partial cutaway of the distal end of the rheolytic thrombectomy catheter of FIG. 24 in operation in a blood vessel. FIG. 1 illustrates a side view of a rheolytic thrombectomy catheter 10 useful for the removal of thrombus, and FIG. 2 illustrates a semi-exploded side view of the rheolytic thrombectomy catheter 10. The rheolytic thrombectomy catheter 10 includes two major assemblies; namely, an outer assembly 12 and an inner assembly 14. The inner assembly 14 aligns concentrically to and within the outer assembly 12 and extends beyond the length of the outer assembly 12. Externally visible components, or portions of components, of the outer assembly 12 of the rheolytic thrombectomy catheter 10, as illustrated in FIGS. 1 and 2, include a manifold 16, also known as a Y-adapter, a hemostasis nut 18 secured in the proximal end 20 of the manifold 16, a Luer connection 22 located at the proximal end 23 of an angled manifold branch 24 extending from the manifold 16, a Luer fitting 26 secured to the distal end 28 of the manifold 16, a strain relief 30 secured to the distal end 28 of the manifold 16 by the Luer fitting 26, and a first tube or catheter 32, having a distal end 33, secured to the manifold 16 by the strain relief 30 and Luer fitting 26. The externally visible components of the inner assembly 14, illustrated in FIG. 2 , include a high pressure second tube or hypo-tube 34, a filter housing/high pressure connection assembly 36 concentrically aligned to and secured over and about the hypo-tube proximal end 38, a configured transitional stop 40 concentrically aligned to and secured over and about the hypo-tube 34 at a point near and adjacent to the hypo-tube distal end 42, a jet cap 44 concentrically aligned to and secured over and about the hypo-tube 34 at the hypo-tube distal end 42, and a guidewire coil 46 concentrically aligned to and secured to one end of the jet cap 44. The high pressure hypo-tube 34 is drawn and is tapered in incremental steps to provide degrees of flexibility along its length. For purposes of example and illustration, the hypo-tube 34 can include a hypo-tube portion 34a at the hypo-tube proximal end 38 having an outer diameter of .018 inch or smaller, and can include a plurality of incrementally stepped down hypo-tube portions 34b-34n each of lesser outer diameter, where the last hypo-tube portion 34n is stepped down to an outer diameter of .008 inch at the hypo-tube distal end 42. The hypo-tube 34 becomes increasingly more flexible from the hypo-tube proximal end 38 towards the hypo-tube distal end 42 due to the incremental diameter decrease along its length. Increasing flexibility along the length of the hypo-tube 34 allows for easier flexed penetration into tortuous vascular paths. Although the hypo-tube 34 is stepped down in increments, the hypo-tube 34 can also be fashioned of a constantly decreasing outer diameter to provide increasing flexibility along its length and shall not be construed to be limiting to the scope of the invention. FIG. 3 illustrates a semi-exploded cross sectional side view of the manifold 16 and adjacent components, where all numerals correspond to those elements previously or otherwise described. The manifold 16 includes a tapered centrally located passage 48 aligned along the longitudinal axis of the manifold 16 and a branch passage 50 extending along the axis of the branch 24 which intersects and is connected to the central passage 48. The manifold proximal end 20 houses a multi-radius cavity 52 including a round outer cavity portion 54 and a connected round inner and smaller cavity portion 56 having a threaded surface 58 on the proximal portion thereof. The hemostasis nut 18 includes a body 62 having a grasping surface 64 extending thereabout, a threaded surface 66 extending from the body 62, an annular surface 63 at the end of the threaded surface 66, and a passageway 68 aligned centrally to the longitudinal axis of the hemostasis nut 18. The passageway 68 has a wide radius at the proximal end which decreases toward the distal end. The initial wide radius is helpful for insertion of the inner assembly 14 or guidewires and the like. A seal 60 aligns to the distally located annular surface 61 of the round inner cavity portion 56 and bears against the annular surface 63 of the hemostasis nut 18 to seal the central passage 48 of the manifold 16 to the passageway 68 in the hemostasis nut 18. The multi-radius cavity 52 and its internal geometry accommodate corresponding geometry of the hemostasis nut 18 and the seal 60. Luer connection 22 extends from the angled manifold branch proximal end 23. A filter 72 aligns at the mouth of the branch passage 50. The filter 72 and a Luer fitting (not illustrated) can be used to prevent any particulate outflow, to provide for metered outflow, or, alternatively, to provide suction for fluid or particle evacuation. Luer fitting 26 is utilized to secure the strain relief 30 and the catheter 32 to the distal manifold end 28. The strain relief 30 is comprised of a tube 31, a central bore 74 internal to the tube 31 which accommodates the catheter 32, an annular flange 76 about the tube 31, and a tapered proximal tube mouth end 78. It is noted that the outer diameter of the tube 31 is constant from the annular flange 76 to the distal tube end 80, and that the outer diameter steadily decreases from the annular flange 76 to the tapered proximal tube mouth end 78 to provide a tapered tube surface 82 which conforms, for purpose of a proper fit, to the taper of the tapered central passage surface 88 of the central passage 48. The tapered proximal tube mouth end 78 allows for easily accomplished alignment of guidewires and other assemblies, such as inner assembly 14 and the like, with a lumen 87 located in the catheter 32. The Luer fitting 26 includes threads 84 which threadingly engage corresponding threads 86 at the distal end 28 of the manifold 16. The Luer fitting 26 bears against the annular flange 76 of the strain relief 30 to force the tapered tube surface 82 of the strain relief 30 against the tapered central passage surface 88 of the central passage 48 to effect a suitable seal. FIG. 4 illustrates a longitudinal sectional view of the filter housing/high pressure connection assembly 36 located at the hypo-tube proximal end 38 of the hypo-tube 34, where all numerals correspond to those elements previously or otherwise described. The filter housing/high pressure connection assembly 36 includes a cylindrical-like body 90 having a threaded surface 92, a tubular cavity 94, fine and course filters 96 and 98 residing in the tubular cavity 94, a central passage 100 extending through the body 90 and connecting to the tubular cavity 94, and a plug-like cap 102, having a central bore 104, extending into the tubular cavity 94 of the body 90. The hypo-tube 34 suitably secures within the central bore 104 of the cap 102. The central passage 100 communicates through fine and course filters 96 and 98 with the lumen 106 of the hypo-tube 34. FIG. 5 illustrates a side view of the transitional stop 40, the jet cap 44 and the guidewire coil 46 aligned over and about the hypo-tube 34 near or at the hypo-tube distal end 42, where all numerals correspond to those elements previously or otherwise described. The relative sizes of the transitional stop 40 and the jet cap 44 with respect to each other and with respect to the sizes of the lumen 87 of the catheter 32 and a stationary stop 150 residing in the catheter 32, as well as details of the transitional stop 40, are discussed in detail below with relation to FIGS. 6, 12 and 13 . FIG. 6 illustrates an isometric view of the transitional stop 40, where all numerals correspond to those elements previously or otherwise described. The one-piece transitional stop 40 includes a tubular body 108 having a central bore 110 and a plurality of guide bars 112a-112n extending radially from the tubular body 108. Guide bars 112a-112n include angled leading edges 114a-114n extending from the leading portion of the body 108 to arced surfaces 116a-116n. The angled leading edges 114a-114n contact a stationary stop 150 in the catheter 32, as later described in detail. Preferably, and for purposes of example and illustration, the arced surfaces 116a-116n describe arcs centered on the longitudinal axis of the tubular body 108; but, in the alternative, the arced surfaces 116a-116n could describe arcs having other centers, or the surfaces could be flat or be of other geometric design, and shall not be construed to be limiting to the scope of the invention. FIG. 7 illustrates a longitudinal sectional view, taken along line 7-7 of FIG. 5, of the transitional stop 40, the jet cap 44 and the guidewire coil 46 aligned and secured over and about the hypo-tube 34 near or at the hypo-tube distal end 42; and FIG 8 illustrates a view of the jet cap 44 looking in the direction of line 8-8 of FIG. 7, where all numerals correspond to those elements previously or otherwise described. The central bore 110 of the transitional stop 40 is aligned and appropriately secured over and about the last hypo-tube portion 34n to affix the transitional stop 40 over and about and near the hypo-tube distal end 42. The proximal end of the transitional stop 40 juxtaposes and abuts the shoulder-like transition 117 between the next to the last hypo-tube portion 34g and the last hypo-tube portion 34n. The jet cap 44 aligns over and about and is secured to the last hypo-tube portion 34n at the hypo-tube distal end 42. As shown in FIGS. 7 and 8, the jet cap 44 is tubular and includes a circular peripheral wall 118 and a circular end wall 120 extending inwardly from one end of the circular peripheral wall 118. Central to the circular end wall 120 is an elongated hole 122 having arcuate ends and opposite sides each having an arcuate mid section and straight portions extending oppositely from the arcuate mid section to the opposite arcuate ends, as shown in FIG. 8. The arcuate mid sections of the opposite sides of the elongated hole 122 are positioned at the center of the elongated hole 122 and are defined by opposing aligned arcuate portions 124 and 126 of common radius. The last hypo-tube portion 34n aligns to and extends through the center of the elongated hole 122 and is embraced by the arcuate portions 124 and 126, thereby dividing the elongated hole 122 into two jet orifices 128 and 130, the jet orifice 128 being defined by the portion of elongated hole 122 to one side of the outer surface of the last hypo-tube portion 34n, and the jet orifice 130 being defined by the portion of elongated hole 122 to the other side of the outer surface of the last hypo-tube portion 34n. At the distal end of the circular peripheral wall 118 is a weld 132 which joins together the circular peripheral wall 118, the extreme tip of the distal end 42 of the hypo-tube 34, the guidewire coil 46 and a tapered core 134. A plurality of orifices including orifices 136 and 138 in the distal end 42 of hypo-tube 34 align within the central cavity 140 of the jet cap 44 for fluid communication from lumen 106 to the central cavity 140 and to the two jet orifices 128 and 130. A weld 142 is also included at the distal end of the guidewire coil 46 to secure the end of the tapered core 134 to the guidewire coil 46 and to provide for smooth entry into a vessel or other body cavity. FIG. 9 illustrates a slightly modified version of the jet cap 44, wherein two distinct jet orifices 144 and 146 are included in the circular end wall 120 in lieu of the elongated hole 122 shown in FIG. 8, and wherein a bore 148 in the circular end wall 120 accommodates the last hypo-tube portion 34n. FIG. 10 illustrates a longitudinal sectional view of the catheter distal end 33 of the catheter 32 taken along line 10-10 of FIG. 2, where all numerals correspond to those elements previously or otherwise described. Illustrated in particular is the multi-radiused stationary stop 150 frictionally engaging the lumen 87 at the catheter distal end 33. One outer radius defines the cylindrical body 152, which frictionally engages lumen 87, and another larger outer radius defines a cap 153 at the end of the stationary stop 150. A central bore 154 aligns coaxially within the cylindrical body 152 and the cap 153. An annular shoulder 156 between the cap 153 and the cylindrical body 152 abuts and aligns to the catheter distal end 33. An angled annular surface 158, which is complementary to the angled leading edges 114a-114n of the transitional stop 40 shown in FIG. 6, is included at the proximal end of the cylindrical body 152. An annular crimp sleeve 160 applied over and about the catheter distal end 33 ensures a positive fixation of the stationary stop 150 in the lumen 87. FIG. 11 illustrates a longitudinal sectional view of the catheter distal end with the jet cap 44 transiting the central bore 154 of the stationary stop 150 and with the transitional stop 40 aligned within the lumen 87 of the catheter 32, where all numerals correspond to those elements previously or otherwise described. FIG. 12 illustrates a longitudinal sectional view of the catheter distal end with the transitional stop 40 aligned within the lumen 87 of the catheter 32 and in mutual engagement with the stationary stop 150, where all numerals correspond to those elements previously or otherwise described. Mutual engagement of the stationary stop 150 with the transitional stop 40 positions the jet cap 44 at a desirable and finite distance from the stationary stop 150 at the catheter distal end 33. Tubular catheter 32 may be constructed of a flexible polymer material and is characterized by an ability to follow over a flexible guidewire through the vasculature of a patient to be treated. Since the tubular catheter 32 may also be subjected to reduced or vacuum pressures in some applications, the tubular catheter 32 should be resistant to collapse or bursting at the pressure differentials employed. Again, for purposes of example and illustration, the catheter 32 can have an outer diameter of about 1016 microns (0.040 inch) or smaller, and an inner diameter of about 711 microns (0.028 inch) which can also taper in diameter. As is well known in the art, the catheter 32 may be advanced and maneuvered through the vasculature such that the catheter distal end 33 may be selectively positioned adjacent to the site of desired surgical action, for example, adjacent to a thrombus obstructing a blood vessel. The stationary stop 150 may be formed from a variety of materials. Preferably, the stationary stop 150 is formed of material identical to that of the catheter 32. The transitional stop 40 is mounted in the hypo-tube 34 at a location spaced apart from the hypo-tube distal end 42 and distal from the hypo-tube portion 34g. The transitional stop 40 has a cross sectional extent such that it may not freely pass the stationary stop 150. The transitional stop 40 has a substantially X-shaped cross section when viewed axially, as in FIG. 13, which allows for fluid passage in a proximal direction. However, as will be discussed subsequently, numerous alternative shapes might be employed for the transitional stop 40 provided that at least passage of the transitional stop past the stationary stop 150 is prevented. Preferably, the distal portion of the transitional stop 40 includes tapered surfaces, such as angled leading edges 114a-114n. The jet cap 44 presents a cross section capable of passing through the central bore 154 of the stationary stop 150. The angled leading edges 114a-114n serve, in juxtaposition with the angled annular surface 158 of the stationary stop 150, to desirably longitudinally position the transitional stop 40 relative to the stationary stop 150. The close longitudinal alignment of the plurality of guide bars 112a-112n within the lumen 87 of the catheter 32 generates lateral spaced relations, such as, for example, a concentric relationship between the first tube or catheter 32 and the second tube or hypo-tube 34, respectively. Preferably, the cross sectional extent of the transitional stop 40 is roughly about 254 microns (0.010 inch) to about 711 microns (0.028 inch); however, the critical consideration in cross sectional dimensions of the transitional stop 40 is that it must pass through the lumen 87 of the first tube or catheter 32 and yet not pass the stationary stop 150. The jet cap 44 is mounted at the distal end 42 of the hypo-tube 34 and includes a guidewire coil 46 extending distally from the jet cap 44. The jet cap 44, guidewire coil 46 and transitional stop 40 are radially symmetrical about the longitudinal extent of the hypo-tube 34. In such an embodiment, the jet cap 44 preferably has a diameter of from about 254 microns (0.010 inch) to about 762 microns (0.030 inch). The hypo-tube 34 preferably has an outer diameter of about 203 microns (0.008 inch) to about 457 microns (0.018 inch) and also includes a continuous high pressure lumen 106 extending from the hypo-tube proximal end 38 to the hypo-tube distal end 42 and continuing into the jet cap 44. When the hypo-tube distal end 42 of the hypo-tube 34 is advanced through the lumen 87 of the catheter 32, the guidewire coil 46 and the jet cap 44 and any portion of the hypo-tube 34 distal from the transitional stop 40 are free to pass the location of the stationary stop 150. However, passage of the transitional stop 40 is prevented by the partial obstruction of the lumen 87 of catheter 32 by the stationary stop 150. Thus, when the distal angled leading edges 114a-114n of the transitional stop 40 engage the angled annular surface 158 of the stationary stop 150, a desired longitudinal relationship is dependably generated between the jet cap 44 and the catheter distal end 33 (at the cap 153) of the catheter 32. Most importantly, the jet cap 44 is oriented and spaced apart and distally situated at a desired relationship to the catheter distal end 33 of the catheter 32. The jet cap 44 is preferably rounded or tapered at the distal end to facilitate advancement of the hypo-tube 34 and to avoid catching or snagging on the interior of the catheter 32, on the stationary stop 150, or on a vessel wall when advanced beyond the catheter distal end 33. Fluid communication between the lumen 87 and the central bore 154 of the stationary atop 150 is allowed longitudinally and in a distal direction about the geometry of the transitional stop 40. As partially shown in FIGS. 5 and 6 and as fully shown in FIG. 13 , longitudinally oriented passages 162a-116n are formed. For example, passage 162a is formed between guide bars 112a and 112b and a portion of the periphery of transitional stop body 108 extending from the proximal region of the transitional stop 40 distally toward and including the angled leading edges 114a-114b. Longitudinally oriented passages 162b-162n are formed in a corresponding fashion. Note particularly that a portion of the lumen 87 remains open where the transitional stop 40 interacts with the stationary stop 150 to allow passage of liquid and small portions of suspended tissue proximally through the catheter 32. FIG. 13 illustrates a cross sectional view of the guide catheter distal end 33 taken along line 13-13 of FIG. 12, where all numerals correspond to those elements previously or otherwise described. Illustrated in particular are the plurality of passages 162a-162n about the transitional stop 40 which allow passage of liquid and small portions of suspended tissue proximally through the lumen 87 of the catheter 32. Although the guide bars 112a-112n include planar side surfaces, other configurations having a rounded intersection or even having non-planar intersecting walls or other variations of longitudinal passages can be utilized and shall not be construed to be limiting to the scope of the invention. MODE OF OPERATION FIG. 14 best illustrates the mode of operation of the rheolytic thrombectomy catheter 10 with particular attention to the catheter distal end 33 and jet cap 44 positioned in a blood vessel 164, artery or the like at the site of a thrombotic deposit and lesion 166. A guidewire is first advanced percutaneously through the vasculature to the site of the thrombotic deposit and lesion 166. For a distal coronary vessel or a vessel of the brain, typically the guidewire has a diameter of 0.010-0.016 inch. This invention can also be applied to larger vessels which require larger diameter guidewires. Once a guidewire has been advanced along the vessel 164 and has reached the thrombotic deposit and lesion, catheter 32, the first tube, which serves as a flexible evacuation tube, can be advanced over the guidewire through tortuous turns to reach the thrombotic deposit and lesion. With the catheter distal end 33 of the catheter 32 positioned near the thrombotic deposit and lesion 166, the guidewire can then be removed from the catheter 32 and the patient's body. The jet cap 44 at the terminus of the second tube or hypo-tube 34 is then advanced within the lumen 87 of the catheter 32 until the transitional stop 40 contacts the stationary stop 150 of the catheter 32. The arced surfaces 116a-116n at the extremities of the guide bars 112a-112n of the transitional stop 40 provide for guidance of the transitional stop 40 along the lumen 87 and also center the jet cap 44 in the center of the catheter 32 during initial transition and provide for centering of the jet cap 44 in the central bore 154 of the stationary stop 150 prior to engagement of the transitional stop 40 with the stationary stop 150. Engagement of the angled leading edges 114a-114n with the stationary stop 150 sets a predetermined gap or distance from the jet cap 44 proximal end to the stationary stop 150. The central bore 154 and lumen 87 of the catheter 32 serve as an evacuation tube at the catheter distal end 33. The rheolytic thrombectomy catheter 10 can then be activated by providing high pressure liquid, preferably saline, to the proximal end of the catheter 32 via the manifold 16. High pressure saline, or other liquid, from the manifold 16 is provided and flows through the lumen 106 of the hypo-tube 34 to exit orifices 136 and 138 leading to the central cavity 140 of the jet cap 44. The high pressure saline exits jet orifices 128 and 130 as retrograde jets 170 of high velocity saline being directed toward the open central bore 154 in the stationary stop 150 at the catheter distal end 33. The high velocity saline jets 170 dislodge tissue from the thrombotic deposit and lesion 166 and entrain it into the saline jets 170 where it is broken up into smaller fragments. Impingement of the saline jets 170 onto the catheter distal end opening creates a stagnation pressure within the evacuation lumen 87 that drives the debris particles of tissue from the thrombotic deposit and lesion 166 toward the proximal end of the catheter 32. A positive displacement piston pump (not illustrated) can be used to provide liquid, preferably saline, under pressure to the proximal end of the hypo-tube 34. A pressure ranging from 500-15,000 psi will provide the energy to create a useful high velocity jet as the saline exits the jet orifices 128 and 130 located at the circular end wall 120 of the jet cap 44. The flow rate of saline can be controlled by adjusting the pumping rate of the positive displacement pump. The proximal end of the catheter 32 interfaces with a suction device through the Luer connection 22 at the manifold branch 24, for example, a roller pump, prior to discharge of the evacuated thrombotic debris into a collection bag for disposal. The rate of evacuation can be controlled by adjusting the rate of the roller pump. The rate of saline inflow can be balanced with the rate of removal of thrombotic debris by simultaneous adjustment of the piston pump and the roller pump. The rate of saline inflow can be less than, equal to, or greater than the rate of removal of thrombotic debris. The rate of thrombus removal can be set to slightly exceed the rate of saline inflow to reduce the likelihood for distal embolization of thrombotic tissue. FIG. 15, illustrates a longitudinal sectional view of the transitional stop 40, an alternative jet cap 180, in lieu of jet cap 44, and a guidewire coil 46a aligned and secured over and about the hypo-tube 34 near or at a hypo-tube distal end 42a; and FIG. 16 illustrates a view of the jet cap 180 looking in the direction of line 16-16 of FIG. 15, where all numerals correspond to those elements previously or otherwise described. The jet cap 180 includes several like components as described previously. The jet cap 180 aligns over and about and is secured to the last hypo-tube portion 34na, which angles downwardly from the longitudinal axis of the hypo-tube 34 at the hypo-tube distal end 42a. The jet cap 180 is tubular and includes a circular peripheral wall 118a and a circular end wall 120a extending inwardly from one end of the circular peripheral wall 118a. Located in the circular end wall 120a are two holes 182 and 184 which support a U-shaped hypo-tube portion 34x extending from the last hypo-tube portion 34na. The U-shaped hypo-tube portion 34x aligns to and extends through the holes 182 and 184 in the circular end wall 120a, as well as through the jet cap central cavity 140a. The free end portion of the U-shaped hypo-tube portion 34x secures in the hole 184 flush with the circular end wall 120a and is open, thereby defining an orifice aligned to direct a high velocity jet stream, preferably saline, in a proximal direction in a manner and fashion such as previously described. At the distal end of the circular peripheral wall 118a is a weld 132a which joins together the circular peripheral wall 118a, the bight of the U-shaped portion 34x of the hypo-tube 34, the guidewire coil 46a and a tapered core 134a. A weld 142a is also included at the distal end of the guidewire coil 46a to secure the end of the tapered core 134a to the guidewire coil 46a and to provide for smooth entry into a vessel or other body cavity. FIG. 16 is a view of the proximal end of the jet cap looking in the direction of line 16-16 of FIG. 15 , where all numerals correspond to those elements previously or otherwise described. FIG. 17, illustrates a longitudinal sectional view of the transitional stop 40, an alternative jet cap 200, in lieu of jet cap 44, and a guidewire coil 46b aligned and secured over and about the hypo-tube 34 near or at a hypo-tube distal end 42b; and FIG. 18 illustrates a view of the jet cap 200 looking in the direction of line 18-18 of FIG. 17 , where all numerals correspond to those elements previously or otherwise described. The jet cap 200 includes several like components as described previously. The jet cap 200 aligns over and about and is secured to the last hypo-tube portion 34nb, which angles downwardly from the longitudinal axis of the hypo-tube 34 at the hypo-tube distal end 42b. The jet cap 200 is tubular and includes a circular peripheral wall 118b and a circular end wall 120b extending inwardly from one end of the circular peripheral wall 118b. Located in the circular end wall 120b is a hole 202, and, preferably, a centrally located jet orifice 206. Preferably one jet orifice is included, although more jet orifices can be utilized and shall not be deemed as limiting to the scope of the invention. The last hypo-tube portion 34nb aligns to and extends through the hole 202 in the circular end wall 120b and has an open end or orifice which ends in the jet cap central cavity 140b of the jet cap 200 for fluid communication from lumen 106 to the central cavity 140b and to the jet orifice 206 to direct a high velocity jet stream, preferably saline, in a proximal direction in a manner and fashion such as previously described. At the distal end of the circular peripheral wall 118b is a weld 132b which joins together the circular peripheral wall 118b, the guidewire coil 46b and a tapered core 134b. A weld 142b is also included at the distal end of the guidewire coil 46b to secure the end of the tapered core 134b to the guidewire coil 46b and to provide for smooth entry into a vessel or other body cavity. FIG. 18 is a view of the proximal end of the jet cap looking in the direction of line 18-18 of FIG. 17, where all numerals correspond to those elements previously or otherwise described. FIG. 19, illustrates a longitudinal sectional view of a transitional stop 210, a jet cap 212 being similar to the configuration of jet cap 180 of FIG. 15 and in lieu of jet cap 44, and a guidewire coil 46c, being similar in configuration to guidewire coil 46a, aligned and secured over and about the hypo-tube 34 near or at a non-angled hypo-tube distal end 42c; and FIG. 20 illustrates a view of the catheter distal end 33 looking in the direction of line 20-20 of FIG. 19 , where all numerals correspond to those elements previously or otherwise described. In this embodiment the jet cap 212 aligns over and about and is secured to the last hypo-tube portion 34nc which projects straight outwardly from the lumen 87 and from transitional stop 210. The longitudinal axis of the hypo-tube 34 and the last hypo-tube portion 34nc is offset from the central axis of the transitional stop 210, at the hypo-tube distal end 42c. Having the last hypo-tube portion 34nc located off-center obviates the requirement of having a last hypo-tube portion which angles downwardly from the longitudinal axis of the hypo-tube 34 and also allows the jet cap 212 to align with the central bore 154 of the stationary stop 150 without having an angled last hypo-tube portion. The transitional stop 210 is fashioned of a solid material having a circular cross section, one end of which is in the form of a truncated cone having an angled annular surface 214 and also having a longitudinally oriented hole 216 distant from the central longitudinal axis of the transitional stop 210 and, in addition, a longitudinally oriented lumen 218 distant from the central longitudinal axis of the transitional stop 210. The transitional stop 210 is positioned as illustrated to position the angled annular surface 214 against the angled annular surface 158 of the stationary stop 150 to position the jet cap 212 at a desirable and finite distance from the stationary stop 150 at the catheter distal end 33 so that a high velocity jet stream, preferably saline, emanating from the open end or orifice of the hypo-tube may be directed in a proximal direction in a manner and fashion toward the lumen 218 to dislodge, break up and carry away thrombotic tissue debris, such as previously described. FIG. 20 illustrates a view of the catheter distal end 33 looking in the direction of line 20-20 of FIG. 19, where all numerals correspond to those elements previously or otherwise described. FIG. 21, illustrates a longitudinal sectional view of a catheter distal end 33a and having alternatively configured stationary and transitional stops, where all numerals correspond to those elements previously or otherwise described. Located at the catheter distal end 33a of the catheter 32 is a stationary stop 230. The stationary atop 230 is permanently connected to, molded to, or otherwise formed to the tubing wall of the catheter 32 and projects into the lumen 87 of the catheter 32. By projecting inward and into the lumen 87, the stationary stop 230, being comprised of a plurality of arcuate stops 230a-230n, partially obstructs the lumen 87. However, the stationary stop 230 does not fully obstruct the lumen 87. Moreover, the stationary stop 230 allows for free passage of a standard guidewire through the lumen 87 in the region adjacent the catheter distal end 33a of the catheter 32. Preferably, and for purposes of example and illustration, the arrangement and dimensions of the stationary stop 230 are such that a coronary or neurological guidewire having a diameter of at least 254 microns (0.010 inch, more preferably 406 microns (0.016 inch), can freely pass the stationary stop 230. Most preferably, the unobstructed diameter of the stationary stop 230 is from about 254 microns (0.010 inch) to about 762 microns (0.030 inch). The catheter 32 has an outer diameter of about 1016 microns (0.040 inch) and an inner diameter of about 711 microns (0.028 inch) or smaller. As is well known in the art, the catheter 32 may be advanced and maneuvered through the vasculature such that the catheter distal end 33a may be selectively positioned adjacent to the site of desired surgical action, for example, adjacent to a thrombus obstructing a blood vessel. The stationary stop 230 has a plurality of arcuate stops 230a-230n aligned parallel to the central axis of the catheter 32, each having a proximal tapered surface 234a-24n and a distal tapered surface 236a-236n. The stationary stop 230 may be formed from a variety of materials. Preferably, the stationary stop 230 is formed of material identical to that of the catheter 32. Most preferably, the stationary stop 230 is fabricated by a permanent deformation and thickening of the wall of the catheter 32 at the desired location. Alternatively, the stationary stop 230 might be separately constructed and then fixed within the catheter 32. The hypo-tube 34, or second tube, is fashioned as previously described having a hypo-tube distal end 42d and a proximal end (not shown). A transitional stop 238 is mounted on the last hypo-tube portion 34nd at a location spaced apart from a jet cap 240 and a guidewire coil 46d also mounted on the last hypo-tube portion 34nd. The transitional stop 238 has a cross sectional extent such that it may not freely pass the stationary stop 230. The transitional stop 238 has a rounded cross section when viewed axially. However, numerous alternative shapes might be employed for the transitional stop 238 provided that at least passage past the stationary stop 230 is prevented. Preferably, the distal surface 242 of the transitional stop 238 is tapered, such that a distalmost extent of the transitional stop 238 presents a cross section capable of passing the proximalmost extent of the stationary stop 230, generally as represented by the proximal tapered surfaces 234a-234n. Distal tapered surface 242 serves a dual function by first facilitating passage and advancement of the hypo-tube 34 by reducing any tendency to catch or bind within the catheter 32, and second, to desirably laterally position the transitional stop 238 relative to the stationary stop 230 and thereby generate lateral relations, such as for example, a concentric relationship between the catheter 32 and hypo-tube 34, respectively. Preferably, the cross sectional extent of the transitional stop 238 is roughly about 0.010 inch to about 0.028 inch; however, the critical consideration in cross sectional dimensions of the transitional stop 238 is that it must pass through the lumen 87 of the catheter 32 and yet not pass the stationary stop 230. As previously mentioned, a jet cap 240 is mounted at the hypo-tube distal end 42d of the hypo-tube 34. A guidewire coil 46d extends distally from the jet cap 240. The jet cap 240, guidewire coil 46 and transitional stop 238 are radially symmetrical about the longitudinal extent of the hypo-tube 34. The jet cap 240 preferably has a diameter of from about 0.010 inch to about 0.030 inch. The hypo-tube 34 preferably has an outer diameter of about 0.008 inch to about 0.018 inch and also includes a continuous high pressure lumen 106 extending from the proximal end to the hypo-tube distal end 42d and continuing into the jet cap 240. When the end of the hypo-tube 34 is advanced through the lumen 87 of the catheter 32, the guidewire coil 46d adjacent the jet cap 240 and any portion of the hypo-tube 34 distal from the transitional stop 238 are free to pass the location of the stationary stop 230. However, passage of the transitional stop 238 is prevented by the partial obstruction of the lumen 87 of catheter 32 by the stationary stop 230. Thus, when the distal tapered surface 242 of the transitional stop 238 engages the proximal tapered surfaces 234a-234n of the stationary stop 230, a desired longitudinal relationship is dependably generated between the jet cap 240 and the catheter distal end 33a. Most importantly, the jet cap 240 is oriented and spaced apart and distally situated at a desired relationship to the distal end 33a of the catheter 32. FIG. 22 illustrates a view of the catheter distal end 33a looking in the direction of line 22-22 of PIG. 21, where all numerals correspond to those elements previously or otherwise described. Illustrated in particular are the plurality of arcuate stops 230a-230n shown in contact with the distal tapered surface 242 of the transitional stop 238. Fluids containing thrombotic debris can pass between the arcuate stops 230a-230n, along the inner wall of the catheter 32 which is adjacent to and between the arcuate stops 230a-230n, along the transitional stop 238, and into the lumen 87 of the catheter 32 for passage to the manifold 16. FIG. 23, illustrates, in partial cross section, a side view of the catheter distal end 33 where the hypo-tube 34 is fixed along the longitudinal axis of the catheter 32, where all numerals correspond to those elements previously or otherwise described. The hypo-tube 34 is appropriately aligned and secured in a central bore 244 of a cylindrical fixture 246 which secures in the end of the catheter 32 by a crimp sleeve 248. A jet cap 250 and a guidewire coil 46e secure to the hypo-tube distal end 42e at the last hypo-tube portion 34ne at a fixed distance from the catheter distal end 33. In this instance, no transitional or stationary stops are incorporated, as the entire catheter system incorporating a longitudinally fixed hypo-tube 34 is inserted into the body without use of a guidewire. The cylindrical fixture 246 has passages with the same profile as passages 162a-162n of the transitional stop 40 for connection to lumen 87 in the catheter 32. FIGURES 24 to 35 relate to a preferred embodiment of the present invention. FIG. 24, illustrates a side view of a rheolytic thrombectomy catheter 310, useful for the removal of thrombus, and FIG, 25 illustrates a semi-exploded side view of the rheolytic thrombectomy catheter 310. The rheolytic thrombectomy catheter 310 includes two major assemblies: namely, an outer assembly 312 and an inner assembly 314 as best shown in FIG. 25. The majority of the components of the rheolytic thrombectomy catheter 310 are comprised of tubular members as described herein. The inner assembly 314 aligns concentrically to and within the outer assembly 312 and extends beyond the length of the outer assembly 312. Externally visible components, or portions of components, of the outer assembly 312 of the rheolytic thrombectomy catheter 310, as illustrated in FIGS. 24 and 25, include a manifold 316, also known as a Y-adapter, a hemostasis nut/stop 318 secured to the proximal end 320 of the manifold 316, a Luer connection 322 located at the proximal end 323 of an angled manifold branch 324 extending from the manifold 316 , a rotatable Luer fitting 326 (screw cap) secured to the distal end 328 of the manifold 316, a Luer. connection 327 having a strain relief 330 and opposing manipulation tabs 329a and 329b which secures to the distal end 328 of the manifold 316 by the rotatable Luer fitting 326, and a first tube or catheter 332, having a distal end 333, secured at the catheter proximal end 337 to the manifold 316 by the strain relief 330 and rotatable Luer fitting 326 and the Luer connection 327. A radio-opaque marker 335 is positioned and fixed over and about the catheter distal end 333. The externally visible components of the inner assembly 314, illustrated in FIG. 25, include a high pressure second tube or hypo-tube 334, a filter housing/high pressure connection stop assembly 336, having opposing manipulation tabs 339a and 339b, which concentrically aligns to and secures over and about the proximal end 338 (FIG. 26) of the hypo-tube 334, a flow director 340 having and being comprised of a connecting expandable exhaust tube 342, a connecting inner body 344, and an optional radio-opaque marker 346 which passes over and about the hypo tube 334 near hypo-tube distal end 348, a jet cap 350 secured to the hypo-tube distal end 348, and a guidewire coil 352 concentrically aligned to and secured to one end of the jet cap 350. The high pressure hypo-tube 334 is drawn and is tapered in incremental steps to provide degrees of flexibility along its length. For purposes of example and illustration, the hypo-tube 334 can include a hypo-tube portion 334a at the hypo-tube proximal end 338 having an outer diameter of 457.2 microns (.018 inch) or smaller, and can include a plurality of incrementally stepped down hypo-tube portions 334b-334n each of lesser outer diameter, where the last hypo-tube portion 334n is stepped down to an outer diameter range of 152.4 microns to 304.8 microns (.006 to .012 inches) at the hypo-tube distal end 348. The hypo-tube 334 becomes increasingly more flexible from the hypo-tube proximal end 338 towards the hypo-tube distal end 348 due to the incremental diameter decrease along its length. Increasing flexibility along the length of the hypo-tube 334 allows for easier flexed penetration into tortuous vascular paths. Although the hypo-tube 334 is stepped down in increments, the hypo-tube 334 can also be fashioned of a constantly decreasing outer diameter to provide increasing flexibility along its length and shall not be construed to be limiting to the scope of the invention. FIG. 26 illustrates a longitudinal sectional view of the filter housing/high pressure connection stop assembly 336 located at the proximal end 338 of the hypo-tube 334, where all numerals correspond to those elements previously or otherwise described. The proximally located filter housing/high pressure connection stop assembly 336 includes a filter housing 349 which mounts in a grasping assembly 341. The filter housing 349 has a cylindrical-like body 360 having a threaded surface 362 utilized for high pressure connection extending therefrom, a tubular cavity 364, fine and course filters 366 and 368 residing in the tubular cavity 364, a central passage 370 concentric to and co-located with the threaded surface 362 and extending through the proximal end of the body 360 and connecting to the tubular cavity 364, and a ferrule 374 residing in the tubular cavity 364 juxtaposing fine filter 366. The grasping assembly 341 includes a tubular body 343 terminating in manipulating tabs 339a and 339b and includes a central bore 345 extending through the tubular body 343 and partially into the region of the manipulating tabs 339a and 339b to intersect bore 347. Bore 347 in the grasping assembly 341 accommodates the body 360 of the filter housing 349 which is suitably secured thereto and therein. The hypo-tube proximal end 338 extends through bore 345 of the tubular body 343 and suitably secures within and frictionally engages the interior of the ferrule 374. The central passage 370 communicates through fine and course filters 366 and 368 with the lumen 372 of the hypo-tube 334. FIG. 27 illustrates an isometric view of the flow director 340, the jet cap 350 and the guidewire coil 352, and FIG. 28 illustrates an exploded isometric view of the flow director 340, the jet cap 350 and the guidewire coil 352, where all numerals correspond to those elements previously or otherwise described. The hypo-tube 334 extends proximally through the flow director 340, and collectively the hypo-tube 334 and the flow director 340 extend proximally through the catheter 332. As illustrated in the unpressurized mode, it is noted that an annulus 378 is formed between the interior annular surface 384 of the catheter 332 and the outer annular surface 386 of the expandable exhaust tube 342. During normal pressurized operation, the expandable exhaust tube 342 expands to cause the outer annular surface 386 of the expandable exhaust tube 342 to expand and impinge the interior annular surface 384 of the catheter 332, thereby eliminating the annulus 378, as later described in detail. The guidewire coil 352 includes a centrally located tapered core 380 of decreasing taper distally to increase flexibility in a distal direction. A weld 382 is also included at the distal end of the guidewire coil 352 to secure the distal end of the tapered core 380 to the guidewire coil 352 distal end and to provide for smooth entry into a vessel or other body cavity. The proximal end of the tapered core 380 suitably secures to a bore 388 at one end of the jet cap 350. The proximal end of the guidewire coil 352 suitably secures to the jet cap 350. The inner body 344 includes a reduced radius neck 390 which is accommodated by the distal end of the expandable exhaust tube 342. The reduced radius neck 390 also includes a slotted cutout 392 for mounting, such as by welding or other suitable means, of the distal end 348 of the hypo-tube 334. Also included, in the interior of the inner body 344, is a passage 394 having a ramped annular surface 396. As the hypo-tube 334 is positioned, during pressurized or unpressurized operation, the flow director 340, the jet cap 350, the guidewire coil 352, and tapered core 380, along with the hypo-tube 334, move and position as a unit to a desired position along a variable displacement distance 383 which is the distance from the distal end 333 of the catheter 332 to the weld 382 at the distal end of the guidewire coil 352. The variable displacement distance 383 can range from a minimum distance where the weld 382 at the distal end of the guidewire coil 352 is positioned just inside the distal end 333 of the catheter 332 to a distance where the proximal end 342a of the expandable exhaust tube 342 is positioned just inside the distal end 333 of the catheter 332, whereby a major portion of the expandable exhaust tube 342, the inner body 344, the space 406, the jet cap 350, the guidewire coil 352, and the tapered core 380 are distally located with reference to the distal end 333 of the catheter 332. At this extended position, further distal movement is prevented by impingement of the filter housing/high pressure connection/stop assembly 336 with the hemostasis nut/stop 318 shown in FIG. 24 . FIG. 29 illustrates a view in cross section of the flow director 340, the jet cap 350 and the guidewire coil 352 along line 29-29 of FIG. 24 in the unpressurized mode, where all numerals correspond to those elements previously or otherwise described. Illustrated in particular is the relationship of the interior annular surface 384 of the catheter 332 and the outer annular surface 386 of the expandable exhaust tube 342 which form the annulus 378. Also illustrated is the jet cap 350 which secures over and about the distal end 348 of the hypo-tube 334. A horizontally aligned bore 398 in the upper region of the jet cap 350 accommodates the distal end 348 of the hypo-tube 334 which suitably secures and seals therein. An orifice 400 located in the distal end 348 of the hypo-tube 334 aligns with a vertically aligned passage 402 to further communicate with a horizontally aligned and rearwardly or proximally aimed jet 404. A predetermined and suitable space 406, is located between the proximal end of the jet 404, which is aligned with the proximal end of the jet cap 350, and, in general, the catheter distal end 333, and, more specifically, to distal end of the ramped annular surface 396 of the inner body 344. The maximum distal position of the space 406 with relation to the catheter distal end 333 is determined by the relationship of the distal end of the filter housing/high pressure connection stop assembly 336 ( FIG. 24 ) and the hemostasis nut/stop 318 which contact each other to limit the distal movement of the hypo-tube 334. The location of space 406 can be determined by observation of the relationship of one or more of the following components, including the radio-opaque marker 335 at the catheter distal end 333, the radio-opaque marker 346, the inner body 344, the jet cap 350, and most commonly by the guidewire coil 352 which is made of platinum, or other components by known observation methods. The hypo-tube 334 can be fashioned of material such as, but not limited to, stainless steel or nickel titanium alloys. FIG. 30 illustrates a view in cross section of the flow director 340, the jet cap 350 and the guidewire coil 352 along line 29-29 of FIG. 24 in the pressurized mode, where all numerals correspond to those elements previously or otherwise described. Subsequent to proper positioning of the appropriate component of the invention in a vessel or other body member in the unpressurized mode, saline 410, under high pressure, is injected through the inner assembly 314 and through the hypo-tube 334 and delivered to the distal hypo-tube portion 334n, orifice 400, passage 402 and thence to jet 404 in the jet cap 350. The pressurized saline exits the jet 404 as a saline jet flow 408 and is directed partially into the ramped annular surface 396 and the passage 394 of the inner body 344 and into the lumen 412 of the expandable exhaust tube 342 to pressurize the expandable exhaust tube 342 causing the expandable exhaust tube 342 to expand and force the expandable exhaust tube outer annular surface 386 to seal against the catheter interior annular surface 384. The saline jet flow 408 also flows to entrain thrombotic tissue adjacent to or lying within the space 406 to break up and erode the thrombotic tissue. Positive pressurized flow of the pressurized saline and the entrained particles of thrombotic tissue is prevented from back flowing out of the previously open annulus 378 which has been subsequently closed by the seal between the inner assembly 314 within the outer assembly 312 and is allowed to travel under full pressurized force along the lumen 412 of the expandable exhaust tube 342 and along a catheter lumen 385 to the manifold 316 and outwardly through the angled manifold branch 324. The ability to insert and maneuver the inner assembly 314 within the outer assembly 312 freely and unhampered and then to subsequently effect a seal between the inner assembly 314 and the outer assembly 312 while maintaining maneuverability contributes to the novelty and usefulness of the invention. FIG. 31 illustrates a view in cross section of the jet cap 350 and the guidewire coil 352 along line 31-31 of FIG. 27 , where all numerals correspond to those elements previously or otherwise described. FIG. 32 illustrates a view in cross section of the junction of the inner body 344 and the expandable exhaust tube 342 along line 32-32 of FIG. 30, where all numerals correspond to those elements previously or otherwise described. Illustrated in particular is the mounting and the securing of the hypo-tube 334 to opposing sides of the slotted cutout 392 in the reduced radius neck 390 of the inner body 344 by welds 414 and 416. Positioning and securing of the hypo-tube 334 in the upper region of the inner body 344 ensures alignment of the jet cap 350, and thus the jet 404, with the inner body 344. FIG. 33 illustrates a view in cross section of the distal end of the rheolytic thrombectomy catheter 310 along line 33-33 of FIG. 29 in the unpressurized mode, where all numerals correspond to those elements previously or otherwise described. Illustrated in particular is the annulus 378 between the catheter interior annular surface 384 and the expandable exhaust tube outer annular surface 386. Annulus 378 allows for ready and adequate passage of the flow director 340 through the catheter 332 during positioning of the inner assembly 314 (FIG. 25). FIG. 34 illustrates a view in cross section of the junction of the distal end of the rheolytic thrombectomy catheter 310 along line 34-34 of FIG. 30 in the pressurized mode, where all numerals correspond to those elements previously or otherwise described. Illustrated in particular is the closing or elimination of the annulus 378 (FIG. 33) between the catheter interior annular surface 384 and the expandable exhaust tube outer annular surface 386. Closing of the annulus 378 allows for sealing of the flow director 340 against the catheter interior annular surface 384 to maintain full pressurization ( FIG. 25 ). MODE OF OPERATION FIG. 35 illustrates a view in cross section and in partial cutaway of the distal end of the rheolytic thrombectomy catheter 310 in operation in a blood vessel 418. FIG. 35, with reference to elements previously or otherwise described in relation to FIGS. 24-34, best illustrates the mode of operation of the rheolytic thrombectomy catheter 310, with particular attention to the catheter distal end 333, the flow director 340 and the jet cap 350 positioned in a blood vessel 418, artery or the like at the site of a thrombotic deposit and lesion 420. A guidewire is first advanced percutaneously through the vasculature to the site of the thrombotic deposit and lesion 420. For a distal coronary vessel or a vessel of the brain, typically the guidewire has a diameter which can range from 254-406.4 microns (0.010-0.016 inches). This invention can also be applied to larger vessels which require larger diameter guidewires. Once a guidewire has been advanced along the vessel 418 and has reached the thrombotic deposit and lesion 420, catheter 332, the first tube, which serves as a flexible evacuation tube, can be advanced over the guidewire through tortuous turns to reach the thrombotic deposit and lesion 420. With the catheter distal end 333 of the catheter 332 positioned near the thrombotic deposit and lesion 420, the guidewire can then be removed from the catheter 332 and the patient's body. The jet cap 350, which can have a lubricious coating to aid in deployment through the lumen 385 of the catheter 332, and guidewire coil 352, at the terminus of the second tube or hypo-tube 334, is then advanced within the lumen 385 of the catheter 332 to a position along the variable deployment distance 383 where the tapered core 380, the guidewire coil 352, the space 406, the inner body 344, and the expandable exhaust tube 342 are positioned as desired beyond the distal end 333 of the catheter 332, whereby the expandable exhaust tube 342 is aligned to the distal end 333 of the catheter 332. The hypo-tube 334 can be of stainless steel or nickel titanium alloy. The passage 394 of the inner body 344, the lumen 412 of the expandable exhaust tube 342, and the lumen 385 of the catheter 332 serve as an evacuation tube at the catheter distal end 333. The rheolytic thrombectomy catheter 310 can then be activated by providing high pressure liquid, preferably saline, to the proximal end of the catheter 332 via the manifold 316. High pressure saline 410, or other liquid, from the manifold 316 is provided and flows through the lumen 372 of the hypo-tube 334 to enter orifice 400 and passage 402 leading to the jet 404 of the jet cap 350 (FIG. 30). The high pressure saline exits jet 404 as high velocity saline jet flow 408 being directed toward the open ramped annular surface 396 in the inner body 344 at the catheter distal end 333: (1) to close the annulus 378 to ensure positive flow without leak-back through an annulus such as annulus 378, as previously described; and, (2) to dislodge tissue from the thrombotic deposit and lesion 420 and entrain the tissue into the saline jet flow 408 where it is broken up into smaller fragments and carried proximally. Impingement of the saline jet flow 408 into the flow director 340 and the co-located catheter distal end 333 opening creates a stagnation pressure within the flow director lumen 412 and catheter lumen 385 (evacuation lumen) that drives the debris particles of thrombotic deposit tissue and lesion 420 toward the proximal end of the catheter 332. A positive displacement piston pump (not illustrated) can be used to provide liquid, preferably saline, under pressure to the proximal end of the hypo-tube 334. A pressure ranging from 34.5 bar to 1034.5 bar (500-15,000 psi) will provide the energy to create a useful high velocity saline jet flow 408 as the saline exits the jet 404 located at the proximal surface of the jet cap 350. The flow rate of saline can be controlled by adjusting the pumping rate of the positive displacement piston pump. The proximal end of the catheter 332 interfaces with a metering device through the Luer connection 327 at the manifold branch 324, for example, a roller pump, prior to discharge of the evacuated thrombotic debris into a collection bag for disposal. The rate of evacuation can be controlled by adjusting the rate of the roller pump. The rate of saline inflow can be balanced with the rate of removal of thrombotic debris by simultaneous adjustment of the piston pump and the roller pump. The rate of saline inflow can be less than, equal to, or greater than the rate of removal of thrombotic debris. The rate of thrombus removal can be set to slightly exceed the rate of saline inflow to reduce the likelihood for distal embolization of thrombotic tissue. The tip at weld 382 can be radio-opaque. The guidewire, coil and mandrel can also be radio-opaque material, such as platinum, iridium or gold alloy. Alternatively, the guidewire coil 352 can be a braided polymer or other suitable material, such as a platinum coil. The guidewire core can be tapered to provide a gradual transition from flexible to stiff in order to negotiate the neuroanatomy. The length can be 0.2 to 2 cm. The exhaust tube portion can direct flow into the exhaust tube and when pressurized can expand to provide a seal. Various modifications can be made to the present invention without departing from the scope of the claims. RHEOLYTIC THROMBECTOMY CATHETER AND METHOD OF USING SAME PARTS LIST 10 rheolytic thrombectomy catheter 12 outer assembly 14 inner assembly 16 manifold 18 hemostasis nut 20 manifold proximal end 22 Luer connection 23 proximal end (branch) 24 branch 26 Luer fitting 28 distal manifold end 30 strain relief 31 tube 32 first tube or catheter 33 catheter distal end 33a catheter distal end 34 second tube or hypo-tube 34a-n hypo-tube portions 34n last hypo-tube portion 34na last hypo-tube portion 34nb last hypo-tube portion 34nc last hypo-tube portion 34nd last hypo-tube portion 34ne last hypo-tube portion 34x U-shaped hypo-tube portion 36 filter housing/high pressure connection assembly 38 hypo-tube proximal end 40 transitional stop 42 hypo-tube distal end 42a hypo-tube distal end 42b hypo-tube distal end 42c hypo-tube distal end 42d hypo-tube distal end 42e hypo-tube distal end 44 jet cap 46 guidewire coil 46a guidewire coil 46b guidewire coil 46c guidewire coil 46d guidewire coil 46e guidewire coil 48 central passage 50 branch passage 52 multi-radius cavity 54 round outer cavity portion 56 round inner cavity portion 58 threaded surface 60 seal 61 distal annular surface 62 body 63 annular surface 64 grasping surface 66 threaded surface 68 passageway 72 filter 74 central bore 76 annular flange 78 tapered proximal tube mouth end 80 distal tube end 82 tapered tube surface 84 threads 86 threads 87 lumen (of 32) 88 tapered central passage surface 90 body 92 threaded surface 94 tubular cavity 96 fine filter 98 course filter 100 central passage 102 cap 104 central bore 106 lumen (of 34) 108 body 110 central bore 112a-n guide bars 114a-n angled leading edges 116a-n arced surfaces 117 shoulder-like transition 118 peripheral wall 118a peripheral wall 118b peripheral wall 120 circular end wall 120a circular end wall 120b circular end wall 122 elongated hole 124 arcuate portion 126 arcuate portion 128 jet orifice 130 jet orifice 132 weld 132a weld 132b weld 134 tapered core 134a tapered core 136 orifice 138 orifice 140 central cavity 140a central cavity 140b central cavity 142 weld 142a weld 142b weld 144 jet orifice 146 jet orifice 148 bore 150 stationary stop 152 cylindrical body 153 cap 154 central bore 156 shoulder 158 angled annular surface 160 crimp sleeve 162a-n passages 164 blood vessel 166 thrombotic deposit and lesion 170 saline jet 180 jet cap 182 hole 184 hole 200 jet cap 202 hole 206 jet orifice 210 transitional stop 212 jet cap 214 angled annular surface 216 hole 218 lumen 230 stationary stop 230a-n arcuate stops 234a-n proximal tapered surfaces 236a-n distal tapered surfaces 238 transitional stop 240 jet cap 242 distal tapered surface 244 central bore 246 cylindrical fixture 248 crimp sleeve 250 jet cap 310 rheolytic thrombectomy catheter 312 outer assembly 314 inner assembly 316 manifold 318 hemostasis nut/stop 320 manifold proximal end 322 Luer connection 323 proximal end (branch) 324 branch 326 rotatable Luer fitting (screw cap) 327 luer connection 328 distal end (manifold) 329a-b manipulation tabs 330 strain relief 332 first tube or catheter 333 distal end (catheter) 334 second tube or hypo-tube 334a-n hypo-tube portions 335 radio-opaque marker 336 filter housing/high pressure connection/stop assembly 337 proximal end (catheter) 338 hypo-tube proximal end 339a-b manipulation tabs 340 flow director 341 grasping assembly 342 expandable exhaust tube 343 tubular body 344 inner body 345 central bore 346 radio-opaque marker 347 bore 348 distal end (hypo-tube) 349 filter housing 350 jet cap 352 guidewire coil 360 body 362 threaded surface 364 tubular cavity 366 fine filter 368 course filter 370 central passage 372 lumen 374 ferrule 378 annulus 380 tapered core 382 weld 384 interior annular surface of catheter 385 catheter lumen 386 outer annular surface of expandable exhaust tube 388 bore 390 reduced radius neck 392 slotted cutout 394 passage 396 ramped annular surface 398 bore 400 orifice 402 passage 404 jet 406 space 408 saline jet flow 410 saline 412 lumen 414 weld 416 weld 418 blood vessel 420 thrombotic deposit and lesion

Claims: A rheolytic thrombectomy catheter (310) for the removal of thrombus from a body vessel or other body cavity, said catheter having an evacuation tube (332) containing a longitudinally positionable high pressure hypo-tube (334) with a jet cap (350) at the distal end (348) thereof for directing a solution backwards towards the distal end (333) of the evacuation tube (332); characterised in that the catheter includes: a. an exhaust tube portion (342), affixed to said hypo-tube (334); b. said exhaust tube portion (342) permitting rotational and longitudinal movement of said hypo-tube (334) relative to said evacuation tube (332) and said exhaust tube portion (342) overlapping (Fig. 27) a portion of said evacuation tube (332) at said distal end (333) thereof and said exhaust tube portion (342) extending distal (Fig. 27) of the distal end (333) of said evacuation tube (332); and c. said hypo-tube (334) and said exhaust tube portion (342) being separable from said evacuation tube (332). The catheter of Claim 1, wherein: a. said exhaust tube portion (342) is expandable; and b. the expandable exhaust tube portion (342) permits rotational and longitudinal movement of said hypo-tube (334) relative to said evacuation tube (332) when in a relaxed, unexpanded state and engages said evacuation tube (332) to seal said hypo-tube (334) in engagement with said exhaust tube portion (342) when in an expanded state, while still providing movement relative to each other; and c. means for causing the expandable exhaust tube portion (342) to expand and engage said evacuation tube (332). The catheter of Claim 2, wherein jet pressure expands said expandable exhaust tube portion (342). The catheter of Claim 2 or 3, wherein said means for causing said expandable exhaust tube to expand comprises an aperture at a distal end portion of said expandable exhaust tube for receiving fluid emitted from said jet cap (350). The catheter of any of Claims 2 to 4, wherein said jet cap contains a rearwardly facing orifice opposite said aperture for directing a flow of said high pressure fluid into said expandable exhaust tube portion (342). The catheter of any of Claims 1 to 5, further including flexible guidewire means (352) affixed to, and extending in axial alignment with, the distal end of said jet cap (350). The catheter of Claim 6, wherein said guidewire means (352) comprises a coil spring and a tapered core (380). The catheter of Claim 7, wherein said tapered core (380) is of a thickness of about 254 microns (.010 inch) to 102 microns (.004 inch) on proximal end to 102 microns (.004 inch) to 51 microns (.002 inch) on distal end. The catheter of any of the preceding claims, for use with a solution at a pressure in a range of 34.5 to 1034.5 bar (500 to 15,000 psi).

Inventors: BONNETTE MICHAEL J, DUTCHER ROBERT G, KOZAK DEBRA M, LE HIEU V, MORRIS JOHN EDWARD PHD, SETUM CINDY M PHD, WIESEL STEVEN E, BONNETTE, MICHAEL J., DUTCHER, ROBERT G., KOZAK, DEBRA M., LE, HIEU V., MORRIS, JOHN EDWARD, PHD., SETUM, CINDY M., PHD., WIESEL, STEVEN E.
Applicants: POSSIS MEDICAL INC, POSSIS MEDICAL, INC.
Application year: 1999
Main classification: A61B17
IPC codes: A61M25, A61B17, A61B19