JPH07265319A - Atherectomy device to open plugged blood vessel - Google Patents

Abstract

PURPOSE: To provide atherectomy equipment to open an occlusive blood vessel by incision, and a method to execute atherectomy by dilating blood vessels from outside to facilitate insertion and extraction of incision tools, and contracting a blood vessel for effective incision. CONSTITUTION: Atherectomy equipment 10 to open occlusive blood vessels 13 has a cross section which becomes narrower as the radial distance from the center of the spiral part, and provided with a flexible spiral guide wire 140 insertable into a blood vessel and a slidable flexible catheter on the wire 140.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an incision device (atherectomy device) for occluding a portion that follows an inner cavity.

[0002]

2. Description of the Related Art There are various atherectomy devices that open blocked blood vessels and the like.

[0003]

BACKGROUND OF THE INVENTION With age, many people develop atherosclerotic obstructions in their blood vessels that reduce circulation and cause serious illnesses such as heart attacks and strokes.

One object of the present invention is to provide an atherectomy system for opening occluded blood vessels.

[0005]

SUMMARY OF THE INVENTION The present invention is an atherectomy device for opening a occluded blood vessel which has a trapezoidal cross-sectional shape that narrows in width as the radial distance from the center of the spiral portion increases. A flexible guidewire assembly insertable into a blood vessel, at least partially formed of a helical wire, and a flexible guidewire assembly slidable on the flexible guidewire assembly having a blade at the end. And a flexible catheter.

[0006]

In accordance with the invention, it is possible to open occluded blood vessels and the guidewire assembly is automatically centered within the catheter. According to the present invention, the blood vessel is expanded from the outside so that the insertion and withdrawal of the atherectomy device can be facilitated, and while the blood vessel is contracted to make the incision more effective, atherectomy can be performed (the term "atherectomy" means This means opening the occluded blood vessel by removing and / or displacing the material that occludes the blood vessel). By alternately expanding and contracting blood vessels in synchronism with the rhythmic delivery operation of the patient's own coronary blood vessels, blood flow in the blood vessels is promoted, thrombus formation is reduced, and the blood vessels and the blood vessels are in charge. It is possible to speed up the healing of the tissue that is damaged.

[0007]

The above and other objects of the present invention will become apparent from the following detailed description and the accompanying drawings.

FIG. 1 shows a patient's heart 1 occluded with an obstruction 12 from the groin through the patient's skin and the patient's arterial system.
A schematic view of one atherectomy device 10 inserted into one coronary vessel 13 is shown. A second atherectomy device 10 (similar parts throughout the drawings are designated by the same reference numeral) has its groin passed through the skin into the blood vessel 13 'of the patient's lower limb 11' that is occluded by an obstruction 12 '. Inserted from. This lower limb shows a state in which the atherectomy device is inserted into the adjacent first chamber 50 through the opening 53 that seals around the lower limb, the second chamber 52, and the opening 51 that also seals around the lower limb. There is. The second chamber has a T-shaped conduit 5 at the sump 54 which is vented to the atmosphere and at the first port of the solenoid valve 55.
Connected by 6. This first chamber 50 is connected by a conduit 57 to the second port of the solenoid valve. The pump 60 has its pressure port connected by a conduit 58 to the third port of the solenoid valve and its suction port by a conduit 59.
Is connected to the fourth port of the solenoid valve.

When the solenoid 61 is not energized, the solenoid valve internally connects its first port to the third port and its second port to its fourth port, as shown by the solid line in FIG. Connected to the port, the pump 60 then creates a negative pressure in the first chamber 50. When the solenoid 61 is excited, the solenoid 61 internally connects the solenoid valve, as shown by the broken line in FIG. 1, and the first port is the fourth port and the second port is the third port. Connect to the port of
The pump then creates a positive pressure in the first chamber.

When the pump 60 creates a negative pressure in the first chamber, the pump 60 reduces the pressure in the tissue of the lower extremity surrounding the blood vessel 13 'and dilates the blood vessel before atherectomy. In addition, it facilitates insertion of the flexible guidewire assembly into the blood vessel. The pump can also be utilized to facilitate withdrawal of the device when surgery is complete. During the implementation of this atherectomy method, the positive pressure in the first chamber increases the pressure in the tissues of the lower limbs,
The effect of the atherectomy method can be enhanced by compressing the blood vessel and drawing more occlusive material into the atherectomy device. At the end of the method, a negative pressure can be applied to the surrounding tissue to dilate the blood vessel, thereby facilitating withdrawal of the atherectomy device.

The medium used in the first and second chambers is a gas, such as the atmosphere, or if there are ulcerative wounds on the legs (often associated with significant atherosclerotic disease).
It is desirable to use sterilizing gases with high oxygen content and antimicrobial agents. Optionally, these chambers are filled with a liquid (eg, a mild saline solution) and cycle rates of tens of minutes per minute without the use of large and noisy pumps and valves. The negative / positive pressures in the first chamber can be rapidly alternated in response to a small amount of liquid being pumped out of or drawn into the chamber at. As the pressure in this first chamber rises and falls, this pressure can cause slight leaks between the chambers. However, since both chambers have liquid, the leakage does not result in air flowing into the first chamber or liquid leaking out of the atherectomy device. If only gas is used as the medium, the second chamber may be omitted to simplify the structure.

Alternating positive and negative pressure is provided by controller 70 which alternately energizes and deenergizes the solenoid through line 72. Further, this control device monitors the rhythmic blood delivery of the patient's own coronary blood vessel through the wire harness 71 (of the type used for the EKG test), and performs the alternate delivery operation of positive pressure and negative pressure. Synchronize to promote blood flow through blood vessel 13 '.

The patient's leg can be maintained in the first chamber for a period of time to reduce the likelihood of a blood clot in the leg and speed the healing of the leg.

Referring to FIG. 2, an atherectomy system 1 for removing occlusive material 12 from within a patient's blood vessel 13 including several elongated members in a telescopic relationship.
0 is indicated. The ends of these components are referred to as "ends" when they reach the inside of the blood vessel, and "proximal ends" mean the other ends. Thus, "terminal direction" means the overall direction from the proximal end to the distal, while "proximal direction"
Shall mean the opposite direction.

This atherectomy device has a flexible guide wire assembly 140 that can be inserted into a blood vessel and a blade 22 at its distal end, and is flexible enough to slide on the flexible guide wire assembly. The catheter 21 of FIG. The flexible catheter 21 forms a passageway 25 around the flexible guidewire assembly for incorporating occlusive material.

In the smaller version of this device, the proximal end of the flexible guidewire assembly is preferably a hollow extension 17 of thin walled stainless steel tubing, while in the larger version it is. The hollow extension preferably comprises a stainless steel wire winding similar to the catheter described in US Pat. No. 4,819,634 of the present application. To the extent that the structure and materials of the helical wire and hollow extension structural elements are similar, they are integrally formed to ensure a secure and economical connection between the helical wire and the hollow extension. It is possible to form.

The hollow extension and the helical wire are
Both are slidable on a flexible guide wire 160, which can be a standard commercially available guide wire. A biocompatible coating, or lubricant, is applied to the various parts of the flexible guidewire assembly to facilitate movement against or against occluded blood vessels, forming a thrombus around it. Can be prevented. Between the coils of the spiral wire 170, spiral voids are formed that capture and retain the occluding material.

Coupling means in the form of a conical sheet 27 connects the flexible catheter to drive means in the form of a motor assembly 28 with a hollow shaft 29. The hollow shaft 29 has a matching tapered end 31,
A seal 32 is provided at the other end. This spiral wire 1
70 eliminates the free play between the flexible guidewire 160 and the flexible catheter 21 that are concentrically aligned with each other. The voids formed between the coils of these helical wires retain the occluded material during atherectomy and limit the excised occluded material to freely rotate around the flexible guidewire. Work.
Also, to the extent that the occlusive material is frictionally rotated by the flexible catheter, the rotation is translated by the helical wire, pushing the hollowed occlusive material toward the proximal end of the passageway.

An optional suction force is applied to the passage 25 through an adaptable suction device through a port 33 which communicates with a groove 34 formed by the housing 28 'of the motor assembly. The groove 34 communicates with a hole 39, which communicates with the hollow shaft 29. This hollow shaft 29 is
It further communicates with the base end of the passage 25. This suction force is provided by the motor and pump assembly 43, which
It is preferably a variable speed motor and the pump is preferably a constant displacement pump such as a piston pump or a peristaltic pump. These pumps limit the volume of blood that is expelled through a passage in a flexible catheter to the pump's displacement volume. Blood only in passage and conduit 4
When flowing through 5, the negative pressure in conduit 45 is low. As the occluding material enters this passage, a higher negative pressure is needed to draw the occluding material proximally, and as the negative pressure increases, leakage and volume loss in the pump increase, causing the conduit 45 to flow through. The flow rate through it is reduced. A signal corresponding to this decrease in flow rate is generated by a flow sensor 44 mounted in conduit 45, which signal is transmitted via line 20 to controller 19, which controls motor / pump assembly 4.
Responding through line 24 by increasing the delivery of 3,
Compensate for these large volume losses. As soon as the occlusive material passes through the atherectomy device and becomes less resistant to flow through the conduit, the flow rate immediately increases, causing the flow sensor to send a corresponding signal to the controller which causes the controller to pump the motor pump. The delivery of assembly 43 is reduced to avoid over-excluding blood from the patient.

A flexible sleeve 71 is used to introduce a flexible catheter into the blood vessel and guide the catheter to the occlusion site. A nipple 72 connected to a flexible sleeve through an annular chamber 73 can be used to deliver fluid into the blood vessel.

FIG. 3 shows an enlarged partial sectional view of the end region of the device designated 3 in FIG. The spiral wire 170 has a trapezoidal cross-sectional shape. As used herein, the term "trapezoidal cross-sectional shape" shall mean a cross-section that narrows in width as the radial distance from the center of the helix increases. For example, the width of the cross-section (width and distance are indicated by double-ended arrows with reference numerals) is line 9
When it is indicated by 0, when the radial distance from the center of the spiral portion has a value indicated by 93, the dimension is indicated by 94, and the width of this cross section becomes narrow to the dimension 92 at the radial distance 91.

Because the narrow side 73 of the cross section is on the outer circumference of the helical wire, this narrow side penetrates deeper into the occluding material than the width side 74, as shown in FIG. The forces generated against the sides of the trapezoidal cross-sections 68, 69 between the displaced occluder and the helical wire are indicated by arrows 75, 76, respectively, and the result of these forces is:
A radial force, shown at 77, is created which urges the helical wire towards the center of the lumen,
The flexible catheter is then biased to follow the lumen, thereby allowing it to remain within the lumen. Furthermore, blood vessels 13
The deeper layers of occluding material that are closer to the walls of the
Results in a tendency to become stiffer. The trapezoidal cross section has a small amount of pushing away this stiff layer, so the overall resistance of the helical wire to travel through the occluding material is, for example, a spiral with a circular or square cross section. Smaller than wire.

To prevent the helical wire from entanglement with the flexible guidewire, its distal entrance to the air gap between its coils is partially closed by a thin arcuate gate 80, which is the gate. The 80 is preferably formed of a radiopaque material so that it may be more visible when viewed using an X-ray machine.

In FIG. 4, a flexible guide wire 16 is shown.
0, an enlarged partial cross-sectional view of a flexible guidewire assembly having a spiral wire 170, a gate 80 and a sharpened distal end 81 of the spiral wire is shown.

FIG. 5 illustrates an enlarged partial cross-section of the distal portion of the device shown at 3 in FIG. 2 utilizing a modified helical wire 170 'consisting of two layers 84, 86, each having a triangular cross-sectional shape. The figure is shown. These two layers are housed together in a plastic jacket 85 and together form a trapezoidal cross-sectional shape. This plastic jacket advances the two layers through the occlusive material as a single piece, but the jacket is sufficiently flexible and does not affect its section modulus. Thus, this multi-layer structure has a significantly smaller section modulus about its neutral axis parallel to axis 87 than the non-layered section of similar dimensions shown in FIG. However, the effect of the multi-layered structure on the section modulus about a neutral axis parallel to the axis 88 is minimal. This improves the ability of the helical wire to fit the curved portion of the blood vessel with minimal loss of torque bearing capacity, which is required for the helical wire to pass through the occluding material. Is Rukoto.

[0026]

The method of performing atherectomy includes the following steps. That is, by expanding the occluded vessel by applying a negative pressure to the surrounding tissue by means such as the first chamber 50 and associated means shown in FIG. 1, and a flexible guidewire assembly. Inserting the distal portion of 140 into the blood vessel and engaging the occluder by advancing the helical wire 170 into the occluder.
Is.

Prior to the initiation of the lumen formation by the flexible catheter, a positive pressure is applied in place of the negative pressure applied to the surrounding tissue, which positive pressure compresses the blood vessel and occludes it. The material is urged onto the spiral wire.

It further includes sliding and distally advancing the flexible catheter 21 over the flexible guidewire assembly to form a lumen through the occluded vessel.

After the flexible catheter has formed the lumen,
Relieving the pressure exerted on the tissue to compress the tissue surrounding the blood vessel, and optionally optionally applying a negative pressure to re-establish the blood vessel.
Extend and facilitate withdrawal of the device.

Finally, the first chamber 50 shown in FIG.
And associated means can be used to facilitate blood flow through the blood vessels by synchronizing positive and negative pressures within the chamber 50 in synchronism with the patient's coronary vasculature. As a result of this increased flow, blood clots are less likely to form in the blood vessels, and their improved circulation can speed up leg healing by providing more nutrients.

Although the present invention has been described with respect to a few embodiments, it should be understood that various modifications and substitutions can be made without departing from the spirit of the invention or the scope of the claims. is there.

[Brief description of drawings]

FIG. 1 shows generally an atherectomy device inserted through the patient's skin and the patient's arterial system into the occluded coronary vessel of the patient's heart through the groin. A second atherectomy device is inserted through the skin in the groin into the occluded vessel of the lower limb located in the vacuum / pressure chamber.

FIG. 2 is a cross-sectional view of an atherectomy device having a flexible guide wire assembly. The intermediate portion of the atherectomy device is omitted for the sake of space in the drawing.

FIG. 3 is an enlarged partial sectional view of a distal end portion of the atherectomy device indicated by reference numeral 3 in FIG.

FIG. 4 is an enlarged partial cross-sectional view of a flexible guidewire assembly.

FIG. 5 is an enlarged partial cross-sectional view of the distal portion of the atherectomy device designated 3 in FIG. 2 utilizing a modified helical wire having a trapezoidal cross-sectional shape.

[Explanation of symbols]

10 atherectomy device 11 heart 12 occluder 13 blood vessel 17 hollow extension 21 catheter 22 blade 24 wire 25 passage 27 conical seat 28 motor assembly 29 hollow shaft 31 tapered end 32 seal 34 groove 39 hole 43 motor pump assembly Solid 44 Flow sensor 45 Conduit 50 First chamber 51 Opening 52 Second chamber 54 Sump 55 Solenoid valve 56 T-shaped conduit 57, 58, 5
9 conduit 60 pump 61 solenoid 70 controller 71 wire harness 72 wire 140 guide wire assembly 160 guide wire 170 to spiral wire

Claims (2)

[Claims] 1. An atherectomy device for opening a occluded blood vessel, at least part of which is a trapezoidal cross-section helical wire whose width narrows as the radial distance from the center of the helix increases. And a flexible guide wire assembly insertable into a blood vessel, and a flexible catheter slidable on the flexible guide wire assembly having a blade at a distal end thereof. Atherectomy device. 2. The atherectomy device according to claim 1, wherein the spiral wire comprises a layered structure.