CATHETER COMPRISING A CUTTING ELEMENT

Abstract

A catheter including a cutting element and an insertion tube, wherein the springy resilient cutting element (1) consists of a sleeve (1a) and profiled longitudinal arms (1b) with sharp endings (1c), protruding from it and directed towards an atraumatic tip (7), wherein the element (1) is mounted on an assembly (2) of an inner tube.

Claims

1. A method of controllably cutting internal areas of walls of a blood vessel, the method comprising: a) providing a catheter comprising a cutting element, an insertion tube and an atraumatic tip on the insertion tube, the atraumatic tip adapted to permit atraumatic insertion of the catheter into a blood vessel, wherein the cutting element is mounted on an assembly of an inner tube located within the insertion tube, and consists of a plurality of springy resilient arms extending from a sleeve, wherein the arms and the sleeve are formed from a section of the inner tube, the profiled springy resilient arms having sharp endings protruding from termini of the arms and directed toward the atraumatic tip, and wherein between the insertion tube and the assembly of the inner tube the catheter defines a channel for fluid supply, and inside the assembly of the inner tube the catheter further defines a channel for a guidewire, and wherein the sharp endings of the springy resilient arms are bent away from the springy resilient arms outwardly in relation to the axis of the catheter so as to permit contact between the sharp endings and an inner wall of a blood vessel; b) adopting a shape of the cutting element to permit repeated and multiple insertion thereof entirely within the insertion tube to permit smooth and rapid multiple repeats of incising the blood vessel; c) inserting said catheter percutaneously into the blood vessel; d) at least partially extending the cutting element from the insertion tube; and e) manipulating said catheter to controllably cut internal areas of the walls of the blood vessel, thus causing the blood vessel to contract and reduce or eliminate blood flow therethrough.

2. The method according to claim 1, wherein the degree of release and unfolding of the plurality of profiled springy resilient arms of the cutting element is adjusted by controlling the position of a distal edge of the insertion tube with respect to the position of the cutting element.

3. The method according to claim 1, which further comprises adjusting the diameter of the of the extended cutting element to at least one of the structure, size and shape of a vessel to be treated by adjusting the position of the insertion tube in relation to the cutting element.

4. The method according to claim 1, wherein the method further comprises administering a dose of a sclerotizing agent through the channel in the catheter and into the blood vessel to further damage the blood vessel by sclerotizing the blood vessel.

5. The method according to claim 4, comprising providing the sclerotizing agent in the form of a liquid solution or a foam.

6. The method according to claim 1, which includes providing markings on an exterior portion of the catheter, the marks being visible with ultrasound or X-ray imaging, to facilitate positioning of the cutting element of the catheter during the operation of the catheter.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The object of the present invention in an exemplary embodiment is illustrated in the drawing, in which

[0023] FIG. 1 shows a general view of the catheter with the cutting element completely released from the insertion tube, with the detail A and the plane of the cross section B-B also marked,

[0024] FIG. 2 shows an enlarged detail A marked in FIG. 1 showing the point of connection of the body tube and the distal tube, as well as the place of mounting the sleeve of the cutting element, and

[0025] FIG. 3 shows an enlarged B-B cross-sectional view of the catheter in the place marked on the FIG. 1,

[0026] FIG. 4 shows the catheter of FIG. 1 in the closed position, with the cutting element hidden under the insertion tube,

[0027] FIG. 5 shows the catheter of FIGS. 1 and 4 in an intermediate position, with a partially extended cutting element, which is partially overlapped by the insertion tube,

[0028] FIGS. 6A and 6B, 7A and 7B, and 8A and 8B show an enlarged structure of the cutting element with, respectively, three, five and ten arms, wherein FIGS. 6A, 7A and 8A show a view of the cutting elements exploded (open) from the side of their sharp ends, and FIGS. 6B, 7B and 8B show a general view of these cutting elements in an enlargement.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0029] The catheter according to the present invention comprises a springy resilient (elastic) cutting element that is mounted on the distal tube 2a of the assembly 2 of the inner tube, and comprises, successively, viewed from the proximal (the operator's) side, the sleeve 1a and the arc-curved longitudinal arms 1b with the properly formed and bent outwards sharpened endings 1c, connected thereto at its distal edge and facing towards the atraumatic tip 7. The arms 1b form a band of identical elements (branches of the cutting element protruding from the axis of the catheter). It is possible to profile the arms 1b in any way in order to achieve the effect of irritation of the vessel wall by the sharp endings 1c. The assembly 2 of the inner tube consists of two concentrically arranged tubes, the distal tube 2a and the body tube 2b of a larger diameter, which is the proximal portion of the assembly 2 of the inner tube. The distal tube 2a is adapted in its diameter to the body tube 2b, so that it is possible to contiguously mount the tubes one in another at the point of their connection (shown in FIG. 2). The body tube 2b supports the tube 2a with a smaller diameter, located further, in the distal portion of the catheter. The sleeve 1a of the cutting element 1 has a diameter equal (or nearly equal) to the diameter of the body tube 2b. The described mutual arrangement of the tubes 2a and 2b and the sleeve 1a is shown in FIG. 2. The insertion tube 3, with a diameter larger than the tube 2a and the sleeve 1a, covers both these elements, together with the arms 1b and the endings 1c of the cutting element, and therefore the cutting element 1 without obstacles can be repeatedly released and retracted by sliding it within the tube 3. The insertion tube 3 has preferably an outer diameter of less than 2.2 mm. Preferably, the sleeve 1a is mounted on the distal tube 2a in such a manner that the proximal edge of the sleeve 1a is in direct contact with the distal edge of the body tube 2b.

[0030] Number of the arms 1b of the cutting element is in the range of 3 to 10, e.g. the cutting element can comprise 3, 4, 5, 6 arms 1b.

[0031] Preferably, the arms 1b in relation to the axis of the sleeve 1a and the axis of the catheter are arranged symmetrically e.g. on the circumference of the sleeve at every 120 (3 arms) or every 90 (4 arms), etc., as shown demonstratively in FIGS. 6A, 7A and 8A. The arms 1b have the form of branches extending from the sleeve 1a and can have a circular cross-section (particularly when formed from wires attached to the sleeve) or approximately trapezoidal cross-section (when formed by cutting out the arms and the sleeve from one section of metal tube). The arms 1b are formed so that when releasing the element 1 from the catheter they radially extend outward, away from the assembly 2 of the inner tube towards the walls of the blood vessel. The arms 1b after full extension of the cutting element (releasing it from the insertion tube 3) are arranged in a section adjacent to the sleeve at an acute angle in relation to the axis of the catheter, e.g. at an angle of 60 or 45. The arms 1b of the end portion, remote from the sleeve 1a, are profiled (bent) arcuately, so that the sharp endings 1c are adjacent to the walls of the vessel. The arms 1b can also be formed as a line similar to the letter S, or in a yet different way, however, the endings 1c are always most remote from the axis of the catheter. Preferably, the sharp endings 1c are bent away from the arms 1b outwardly with respect to the axis of the catheter, i.e. they are more strongly curved outwardly than the line of curvature of the arms 1b. The endings 1c can be conically pointed or can create slightly elongated blade by flattening the end sections of the arms 1b.

[0032] The cutting element 1 can be completely cut out from the section of the tube of metal or other material and then the beginning of such a tube is not treated (the sleeve remains) and in the remaining portion of the tube cutting is carried out to obtain a desired number of arms, therefore 3 to 10 arms are cut in the tube. It is also possible to prepare the cutting element 1 by mounting previously prepared single arms 1b to the section of the tube (the sleeve). These arms are mounted to the sleeve in such manner that the diameter of the retracted cutting element 1 along its length does not exceed the diameter of the sleeve 1a, when the element 1 is retracted in the insertion tube 3. As a result, the catheter can have a minimum diameter limited only with the diameter of the sleeve 1a, increased by the addition of the insertion tube 3. Between the insertion tube 3 and the assembly 2 of the inner tube the space is maintained constituting the channel 13 for fluid supply, for example of sclerotisation chemicals (including foams), pharmacologically active agents, saline solution, etc. Inside the assembly 2 of the inner tube, along the entire catheter, the channel 12 for the guidewire was led, preferably for the guidewire of the dimension 0.035. The guidewire provides stable positioning of the catheter during the procedure.

[0033] In its proximal portion, the catheter comprises known in the art elements accessible for the operator, enabling control of the device. Subsequently, from the proximal side, the catheter is provided with the cap 5 of the assembly of the inner tube, from which the cuff 9 of the assembly of the inner tube is led, next the Y cap 6 and the cap 4 of the insertion tube. The cap 4 and the Y cap 6 are used together to control the insertion tube.

[0034] On the distal tube 2a, at its end, after the cutting element 1, there is mounted the atraumatic soft tip 7 enabling atraumatic insertion of the catheter into the vessel. The catheter can preferably comprise markers visible through ultrasound and/or X-ray imaging, enabling operation of the device during procedure. On the insertion tube 3, at its distal portion, there is provided the marker 8, and on the body tube 2b, at its proximal side, there is provided the first marker 10 followed by the second marker 11. Along the entire catheter there is led the internal channel 12 for the guidewire, shown as the middle space in FIG. 3.

[0035] The catheter is inserted into the blood vessel within the guidewire previously positioned in said vessel, through a typical shrink in the position where the insertion tube 3 covers the entire retracted cutting element 1 (the arms 1b and the endings 1c then adhere to the distal tube 2a). The insertion tube 3 comes then to the soft tip 7the catheter is closed. Full extension of the cutting element 1 occurs when pushing the cap 5 all the way to the Y cap 6.

[0036] To lock the position of the assembly 2 of the inner tube in relation to the insertion tube 3 one needs to tighten the nut on the Y cap 6. Tightening the nut seals the space between the insertion tube 3 and the assembly 2 of the inner tube, and thus venting of the channel 13 shown in FIG. 3 is possible. At the distal portion of the insertion tube 3 there is applied the marker 8, which after extension off the shrink during procedure means that the cutting element 1 is now pushed all the way to the shrink. At the proximal portion of the assembly 2 of the inner tube there are applied two markers. The marker 11 means complete retraction of the cutting element 1 in the catheter, the marker 10 means partial extension of the cutting element 1.

[0037] FIG. 5 shows the cutting element 1 partially extended (released) from the insertion tube 3. In such a position, the cutting element can also fulfil its function, i.e. the sharp ends 1c are in contact with the inner wall of the vessel and cause its longitudinal incisions when moving the catheter. The described construction of the catheter thus does not require the use of a completely extended cutting element 1 during the procedure. Depending on the structure, size and shape of the affected vessel, the operator can smoothly grade the folding of the arms 1b, i.e. adjust the diameter of the extended cutting element to the diameter of the vessel by adjusting the position of the insertion tube 3 in relation to the element 1. The Y cap 6 enables locking the cutting element at a predetermined position.

[0038] The above described construction of the catheter allows smooth and fast multiple repeats of the procedure of incision of the vessel, i.e. its mechanical sclerotisation/obliteration. The cutting element 1 is susceptible to reproducible, multiple insertions of it entirely within insertion tube 3. After the insertion of the catheter and release of the cutting element 1 from the insertion tube 3, it is moved with a uniform motion in the reverse direction (back to the operator), which causes longitudinal incision (irritation, scratch) of the vessel endothelium along the required length of the sclerotised vein. Then the cutting element 1 can be retracted in the insertion tube 3 (still intravascularly), moved in this closed position again to a remote (from the operator) portion of the vessel, and then released again, so that the process of incision of the vessel is repeated on the same or another portion of the vessel. As a result of irritation of the vessel there are almost immediately caused contractions of the vessel and its closure.

[0039] The procedure using the catheter according to the present invention can be carried out also as a mechanical and chemical sclerotisation. In such a case the operations described above are repeated, but through the side channel of the Y cap 6 there is additionally administered a dose of sclerotisation agent in the form of a liquid solution or a foam prepared using the Tessari method. The catheter is pulled (withdrawn) with a uniform motion, cutting the endothelium of the vein with the cutting elements 1 while injecting sclerotisation agent. As before, the operation should be performed over the entire length of sclerotised vein. Mechanical and chemical sclerotisation of the same vein can be performed repeatedly.

THE MARKS ON THE DRAWINGS

[0040] 1 cutting element [0041] 1a sleeve of the cutting element [0042] 1b arm/arms of the cutting element [0043] 1c sharp ending of the arm [0044] 2 assembly of the inner tube [0045] 2a distal tube [0046] 2b body tube [0047] 3 insertion tube [0048] 4 cap of the insertion tube [0049] 5 cap of the assembly of the inner tube [0050] 6 Y cap [0051] 7 soft tip [0052] 8 marker of the insertion tube [0053] 9 cuff of the assembly of the inner tube [0054] 10 first marker of the body tube [0055] 11 second marker of the body tube [0056] 12 channel for the guidewire [0057] 13 channel for fluid supply