ATHERECTOMY CATHETER DEVICE

Abstract: Atherectomy device for removing material from an atheroma in the vascular system includes a cutter (38) mounted in a cylindrical housing (36) having a cutout (37) on one side thereof at the distal end of a catheter. The catheter has a single luminal opening (16), and a flexible drive cable (27) for operating the cutter (38) passes through this opening (16). An inflatable balloon (51) is positioned outside the housing (36) opposite the cutout (37), and a medium for inflating the balloon is introduced through the luminal opening (16) of the catheter.

Description: This invention relates to an atherectomy catheter device. In EP-A-0163502 there is disclosed an atherectomy device which utilizes a multi-lumen flexible tubing. One of the lumens can be utilized for a cutter cable whereas another lumen can be utilized as a balloon inflating lumen. Other lumens may be used for introducing radiopaque materials or making pressure measurements and the like. It has been found that the use of such a multi-lumen tubing has certain disadvantages, particularly when it is desired to make a very small catheter apparatus which can be utilized in conjunction with the heart, kidney and the like. By way of example, it is desirable to have tubing which will make possible a five French device and possibly as small a device as a three French device. In addition to having a smaller size, there is the additional desirability of having a tubing which is very flexible. The problem of the present invention is to improve the known catheter device in order to facilitate its use on the operating table. According to this invention there is provided an atherectomy catheter device for removal of material from an atheroma in a vessel of the vascular system of a patient, comprising an elongate generally cylindrical housing formed with a cutout extending longitudinally of the housing on one side thereof, atheroma cutting means disposed within the housing, flexible guiding means secured on the proximal end of the housing for advancing the housing into the vessel, flexible drive means connected to the atheroma cutting means, inflatable means carried by the housing and disposed on the exterior of the housing opposite the side in which the cutout is formed, and means including an inflation port for establishing communication between the inflatable means and the inflation port, characterised in that said flexible guiding means has only a single lumen extending therethrough, said flexible drive means extending through said single lumen, said means including said inflation port being in communication through the single lumen with a port for establishing communication between the inflatable means and the inflation port, rotatable coupling means connecting the flexible guiding means to the means including an inflation port connected into the single lumen so as to permit rotation of the housing and the flexible guiding means independently of rotation of the means including an inflation port and the flexible drive means, and first and second fluid-tight means carried by the housing and the means including an inflation port, respectively, for establishing distal and proximal seals about the flexible drive means so that the single lumen provides a fluid-tight passage between the inflation port and the inflatable means. Preferred embodiments of the catheter device are defined in the dependent claims. The device of the invention can be made very small, and can be very flexible. The invention will now be described by way of example with reference to the drawing, in which: Figure 1A is a view partially in cross section of the proximal end portion of a catheter device according to the present invention; and Figure 1B is an enlarged cross sectional view of the distal end portion of the catheter device according to the present invention. The atherectomy catheter device shown in Figure 1A comprises an elongate flexible tubular member 12 formed of suitable plastics material and which can be provided if desired with a braided reinforcement 13. The flexible tubular member 12 can have an outside diameter ranging from 1.25 to 5mm (.050 to .200 inches). It is provided with a single lumen 16 extending the length thereof from the proximal to the distal extremities. A fitting 17 is provided near the proximal extremity of the flexible tubular member 12. The fitting 17 serves as a catheter tube attachment and has another fitting 18 threadedly mounted therein. A rotating seal assembly 19 is mounted in the fitting 18. A single arm adapter 21 is mounted in the rotating seal member 19. As shown in Figure 1A, the proximal extremity of the flexible tubular member 12 extends through the fitting 17 and 18 and through the rotating seal device 19. Thereafter it passes into the proximal extremity of the adapter 21. A side arm 22 of the adapter 21 is in communication with the single lumen 16 in the flexible tubular member 12 and serves as an inflation port. Another fitting 23 is mounted in the adapter 21. The adapter 21 is provided with a flow passage 24 and the fitting 23 is provided with a flow passage 26. A flexible hollow cutter drive cable 27 is disposed in the passages 24 and 26 in the adapter 21 and fitting 23 and extends into the single lumen 16 provided in the flexible tubular member 12. A fitting 28 having a knurled flange or knob 29 is threaded into the fitting 23 and engages an O-ring 32. The drive cable 27 extends through a passage 33 provided in the fitting 28. The O-ring 32 forms a fluid-tight seal between the fitting 23 and the flexible drive cable 27. The fitting 28 is provided with a tapered portion 28a which is adapted to form a friction fit with a tapered bore 34 in a motor drive unit 35 of the type described in our co-pending European patent application published under no. EP-A-0244058. A housing 36 is mounted on the distal extremity of the flexible tubular member 12 and can be formed of a suitable material such as stainless steel. It is generally cylindrical as shown and has its proximal extremity secured to the distal extremity of the flexible tubular member 12 as shown particularly in Figure 1B. A cutout 37 is provided in the housing 36 in one side thereof and faces in a direction which is generally perpendicular to the longitudinal axis of the housing. A work performing device in the form of a cutter 38 is slidably mounted in the housing 36 and is provided with a circular cutting edge 39 which lies in a plane perpendicular to the longitudinal axis of the housing and the axis of longitudinal movement for the cutter 38. A bell-shaped recess 41 is provided within the cutter 38 and extends rearwardly from the cutting edge 39. The cutter 38 is provided with a hub 42 which is secured to the distal extremity of the flexible drive cable 27. Means is provided for forming a fluid-tight seal between the housing and the flexible drive cable 27 and consists of a sleeve 43 which is secured within the housing by suitable means such as an adhesive and which is provided with a passage 44 through which the flexible drive cable 27 extends. An O-ring 46 is mounted in a recess 47 and is held in place by a retaining ring 48. With the construction shown, the O-ring 46 is compressed in such a manner so as form a fluid-tight seal between the sleeve 43 and the flexible drive cable 27. Means is provided on the exterior of the housing 36 for yieldably urging the housing in the direction the cutout 37 faces and consistsw of an inflatable balloon 51 which is secured to the housing by suitable means such as an adhesive. The distal extremity of the balloon can be secured in a suitable manner to a nose piece 52 by suitable means such as nylon wire 53 wound into a recess 54 provided in the nose piece 52. (Nylon is a Registered Trade Mark). The nose piece 52 is secured in the open distal end of the housing 36 by suitable means such as an adhesive. The nose piece 52 is provided with a rounded forwardly extending surface 55. A conventional flexible elongate guide wire 56 provided with a helical coil spring 57 at its distal extremity is removably mounted in the atherectomy device. The guide wire 56 extends through the hollow flexible drive cable 27, through a bore 58 in the cutter 38, the housing 36 and through a bore 59 provided in the nose piece 52. The guide wire 56 serves as a guiding element for inserting the catheter into a vessel in the vascular system of a patient. As shown in Figure 1B, the nose piece 52 is provided with a relatively large recess 61 which opens up into the interior of the housing 36 and extends forwardly from the housing. The proximal extremity of the balloon 51 is connected in a suitable manner with the single or sole lumen 16 in the flexible tubular member 12 so that the balloon can be inflated and deflated as desired. Thus as shown, the balloon is provided with a reinforced proximal extremity 66 which extends through a hole 67 provided in the housing 36 and opens into a space 68 forward of the sleeve 43 and distal of the distal extremity of the flexible tubular member 12 so that the space 68 is in communication with the single lumen 16. As described in EP-A-0244058 a thumb flipper member 71 is provided which is secured to the flexible drive cable 27 for moving the flexible drive cable 27 and the cutter 28 carried thereby longitudinally of the axis of rotation of the drive cable 27. The operation and use of the single lumen atherectomy catheter device will now be briefly described. In general, the mode of operation of this atherectomy device is very similar to that described in EP-A-0163502 As described in that publication the atherectomy device 11 can be utilized for removing atheromas or at least portions thereof from a vessel in the vascular system of a patient such as an arterial vessel of the heart. The movable guide wire 56 is inserted into the atherectomy device 11 after the guide wire 56 has been inserted into the vessel of the patient with its distal extremity in the desired position. The proximal extremity of the guide wire 56 is threaded into the nose piece 52, the cutter 38 and into the hollow cutter cable 27. After the device has been inserted into the arterial vessel and is positioned in such a manner so that the cutout 37 is opposite the atheroma, the balloon 51 can be inflated by introducing an inflating medium through the single lumen 16 to urge the housing 36 toward the atheroma so that the atheroma enters the cutout 37. If desired, the guide wire 56 now can be removed and the motor drive unit 35 attached. With the cutout 37 held in place by the inflated balloon 51, the cutter 38 can be rotated by the motor drive unit 35 to cause rotation of the flexible drive cable 27 and the cutter 38 mounted thereon. The cutter 38 can be advanced by operating the flipper member 71 in a manner described in EP-A-0244058 to advance the cutter to engage the atheroma which has been forced into the cutout 37. The material which is shaved off or removed by the cutter is collected in the recess 41 within the cutter and also can be collected by the recess 61 in the housing 36 as the cutter is advanced beyond the cutout. Thereafter, the atherectomy device can be removed and the material which has been collected within the recesses 41 and 61 removed. If necessary, the atherectomy device 11 can be inserted repeatedly into the arterial passge and the additional cuts made until as much as desired, or at least a substantial portion of the atheroma has been removed from the vessel so as to permit increased blood flow through the vessel. From the foregoing it can be seen that the atherectomy device described can be utilized for the same shaving operations on the vessel wall as the atherectomy device disclosed in EP-A-0163502 The construction of the present atherectomy device, however, is much smaller because of its use of only a single lumen 16 in the flexible tubular member. The flexible drive cable 27 for the cutter 38 is disposed in the single lumen 16 which is made possible by the use of seals provided at the distal and proximal extremities of the flexible drive cable in the form of the O-rings 32 and 46. This construction also makes it possible to utilize the same single lumen 16 for the balloon inflation lumen which can be inflated from the balloon inflation port 22. The balloon 51 is attached to the housing 36 in such a manner so that its proximal extremity opens up directly into the single lumen 16. In addition with the construction shown, the use of the rotatable member 19 and the rotatable seal provided by the O-ring 46 makes it possible to rotate the housing 36 and the tubular member 12 independently of the motor drive unit 35 and any balloon inflation device connected to the port 22. This facilitates use of the atherectomy device on the operating table when performing the desired operations on the patient. Also one of the more important features of the present construction for an atherectomy device is that it lends itself to smaller atherectomy devices. Thus an atherectomy device as small as a five French device or even a three French device can be made. The five French device has an outer diameter or less than 1.65mm (.065 inches) whereas a three French device has an outer diameter of 0.975mm (.039 inches). By providing atherectomy devices of such a size, it is possible to perform operations in very small blood vessels, as for example, those associated with the heart and kidney, as well as other organs in the body. The construction of the atherectomy device also permits use of a movable guide wire in place of a fixed guide wire.

Claims: An atherectomy catheter device for removal of material from an atheroma in a vessel of the vascular system of a patient, comprising an elongate generally cylindrical housing (36) formed with a cutout (37) extending longitudinally of the housing (36) on one side thereof, atheroma cutting means (38) disposed within the housing (36), flexible guiding means (12) secured on the proximal end of the housing (36) for advancing the housing (36) into the vessel, flexible drive means (27) connected to the atheroma cutting means (38), inflatable means (51) carried by the housing (36) and disposed on the exterior of the housing (36) opposite the side in which the cutout (37) is formed, and means (21) including an inflation port (22) for establishing communication between the inflatable means (51) and the inflation port (22), characterised in that said flexible guiding means (12) has only a single lumen (16) extending therethrough, said flexible drive means (27) extending through said single lumen (16), said means (21) including said inflation port (22) being in communication through the single lumen (16) with a port (67) for establishing communication between the inflatable means (51) and the inflation port (22), rotatable coupling means (19) connecting the flexible guiding means (12) to the means (21) including an inflation port (22) connected into the single lumen (16) so as to permit rotation of the housing (36) and the flexible guiding means (12) independently of rotation of the means (21) including an inflation port (22) and the flexible drive means (27), and first (46) and second (32) fluid-tight means carried by the housing (36) and the means including an inflation port (22), respectively, for establishing distal and proximal seals about the flexible drive means (27) so that the single lumen (16) provides a fluid-tight passage between the inflation port (22) and the inflatable means (51). A device as claimed in Claim 1, characterised in that said first fluid-tight means (46) is disposed distal of the distal extremity of the single lumen (16). A device as claimed in Claim 2, characterised in that said first fluid-tight means (46) is disposed within the housing (36). A device as claimed in any preceding claim, characterised by a movable guide wire (56) extending through the flexible drive means (27).

Inventors: GIFFORD, HANSON SMILEY III, SIMPSON, JOHN BUSH
Applicants: DEVICES FOR VASCULAR INTERVENTION, INC.
Application year: 1987
Main classification: A61B17
IPC codes: A61B17