WO2014080424A2

WO2014080424A2 - The atherotome (vascular cutting device)"

Info

Publication number: WO2014080424A2
Application number: PCT/IN2013/000705
Authority: WO
Inventors: Gnanaraj ANAND
Original assignee: Anand Gnanaraj
Priority date: 2012-11-22
Filing date: 2013-11-20
Publication date: 2014-05-30
Also published as: WO2014080424A3

Abstract

This invention relates to an intravascular cutting device to open hard vascular lesion particularly to act directly on the plaques or calcified blood vessels and eliminatin balloon configuration. The device is for use in interventional cardiology in an arter which is configured with plurality of blades mounted in winged openable/closeabl configuration forming around a shaft. The device is openable/closeable with a handle These blades can be pulled selectively radially outwardly like an umbrella. The cuttin arms are conventional.

Description

Title: THE ATHEROTO E (VASCULAR CUTTING DEVICE)

Field of Invention

A intra vascular cutting device to open hard vascular lesions. Prior Art

Atherectomy devices have been used for a long time in interventional cardiology. There are many types of devices available to reduce or manage the atherosclerotic plaques in the blood vessels. There are four types of atherectomy devices: orbital, rotational, laser, and directional. The decision, to use which type of device is to be used is made by the interventionist, based on a number of factors. They include the type of lesion being treating, the physician's experience with each device, and interpretation of the devices' risks and effectiveness. The basic principles are either removal of the atherosclerotic plaque by cutting it out or by abrading it with an abrasive device or laser. All the devices have their advantages and disadvantages. Currently the device most used for this purpose is a rotablator. The other device that is used to break the circumferential calcium in the blood vessels is the cutting balloon (Flextome® Cutting Balloon® Dilatation Device). This employs four cutting blades in the external surface of the balloon. The crimped balloon is advanced into the artery where the hard lesion is present and the balloon is inflated from outside. As the balloon opens the blades open out and cut into the lesion and breaks the circumferential calcium.

The problems suffered in prior art are many.

Though this cutting balloon has been used for a long time, the mechanics of the cutting balloon is very mechanically inefficient. The concept of pushing a blade over a surface using a sheet of pliable material is poor physics. This makes the blade inefficient and the pressure exerted by the blade less forceful and unpredictable. Moreover, the control over the cutting process is minimal, since the blades cut at high pressures and may exert the pressure only at maximal inflation. This dictates

I

the need for balloons of many sizes to cater for different blood vessels so that the balloons do not over expand inside the lesions and cut through the vessel wall.

The US 5.071.424A shows a catheter atherotome and method for its use for performing partial atherectomy in an artery and thereby enlarging the lumen effectively available for blood flow through the artery. Several blades are mounted at a distal end of a catheter, in a helical basket configuration and spaced angularly apart from one another about the associated ends of two concentric sheaths in such a way that longitudinal and rotary relative movement of the sheaths selectively bows the blades accurately outwardly into a cutting position or draws the blades flat into alignment with the sheaths. The blades have sharpened cutting edges extending helically and directed toward the catheter's proximal end when the blades are bowed.

Partial removal of an atheroma is effected by manually pulling the basket knife past an atheroma with the basket blades in their outwardly bowed cutting positions, with the speed, force, and amount of expansion of the blades determined by the operator. Removal of cutaway pieces of atherosclerotic plaque material is accomplished either by pull-back of a balloon embolectomy catheter or by use of a latex membrane enshrouding the spiral wire blades to trap the shavings within the membrane.

The US 5,074,871 A catheter atherotome and method for its use for performing partial atherectomy in an artery and thereby enlarging the lumen effectively available for blood flow through the artery. An expansible cutter head at the distal end of a catheter includes several elongate flexible members mounted in a parallel array and spaced angularly apart from one another about the associated ends of two concentric members of the catheter in such a way that longitudinal and rotary relative movement of the members of the catheter selectively either bows the flexible members arcuately outwardly into a cutting position or draws them into alignment parallel with the catheter. A sharpened edge of a blade carried on at least one flexible member extends circumferentially and is directed toward the catheter's proximal end when the flexible members are bowed. Partial removal of an atheroma is effected by manually pulling the cutter head past an atheroma with the sharpened ^edge exposed, with the speed, force, and amount of expansion of the cutter head determined by the operator. Removal of cut-away pieces of atherosclerotic plaque material is accomplished either by pull-back of a balloon-tipped catheter or by use of a membrane enshrouding the cutter head to trap the shavings.

The US 2006/0015134 Al An expandable balloon for a medical device having a static state, at least one first expanded state, and at least one second expanded state, the expandable balloon having a substantially polygonal geometric shape in the static state.

The US 6,165,187 shows A catheter atherotome and method for its use for performing partial atherectomy in an artery and thereby enlarging the lumen effectively available for blood flow through the artery. Several blades are mounted at a distal end of a catheter, in a helical basket configuration and spaced angularly apart from one another about the associated ends of two concentric sheaths in such a way that longitudinal and rotary relative movement of the sheaths selectively bows the blades arcuately outwardly into a cutting position or draws the blades flat into alignment with the sheaths. The blades have sharpened cutting edges extending helically and directed toward the catheter's proximal end when the blades are bowed. Partial removal of an atheroma is effected by manually pulling the basket knife past an atheroma with the basket blades in their outwardly bowed cutting positions, with the speed, force, and amount of expansion of the blades determined by the operator. Removal of cut-away pieces of atherosclerotic plaque material is accomplished either by pull-back of a balloon embolectomy catheter or by use of a latex membrane enshrouding the spiral wire blades to trap the shavings within the membrane.

The US 5,282,484 a catheter atherotome and method for its use for perfornning partial atherectomy in an artery and blood flow through the artery. Several blades are mounted at a distal end of a catheter, in a helical basket configuration and spaced angularly apart from one another about the associated ends of two concentric sheaths in such a way that longitudinal and rotary relative movement of the sheaths selectively bows the blades acutely outwardly into a cutting position or draws the blades flat into alignment with the sheaths. The blades have sharpened cutting edges extending helically and directed toward the cathether's proximal end when the blades are bowed. Partial removal of an atheroma is effected by manually pulling the basket knife past an atheroma with the basket blades in their outwardly bowed cutting positions, with the speed, force, and amount of expansion of the blades determined by the operator. Removal of cut-away pieces of atherosclerotic plaque material is accomplished either by pull-back of a balloon embolectomy catheter or by use of a latex membrane enshrouding the spiral wire blades to trap the shavings within the membrane.

Object of Invention

The main object of invention is to create a device that acts directly on the plaque or calcified blood vessel and cuts . with better mechanical energy. The key to achieve this is to eliminate the balloon and make the device mechanically driven instead of fluid pressure driven.

Drawings

Fig.1 - ATHEROTO E

Fig.2 - DOUBLE HINGE VIEW

Fig.3 - ATHEROTOME -END VIEW (OPEN BLADES)

Fig.4 - ATHEROTOME -END VIEW (CLOSED BLADES)

Fig.5 - MODIFICATION -1 -ATHEROTOME

Fig.6 - SAW TOOTH CONFIGURATION

Part Numbers

1. Guide Wire

2. Soft Tubing catheter

3. Single Hinge

. Double Hinge

5. Support / Opening arms ^6. Coaxial guide wire port

7. Core shaft

8. Blade opening shaft

9. Sliding groove

10. Leading / cutting arm

11. Cutting Teeth

12. Hinge Pins

13. Cutting edge

14. Retracted blades

15. Screw handle

16. Back grip

17. Atherotome's open diameter

18. External covering

19. Screw shaft

20. Core metal shaft

21. Outer soft catheter

22. Sliding arms

23. Secondary movement hinge

24. Cutting edge

25. Primary movement hinge

26. Blunt end

Description of Invention

This device is designed to work over a 0.014 wire.

The cutting end of the device is the distal part of the device. The distal part of the device (Fig -1) is the atherotome that is made of cutting arms and a mechanism to open the cutting arms in a controlled fashion. Essentially, the cutting arms are pushed out of their closed position by a central core that when moved opens the arms out like an umbrella. The cutting arm is designed to have four arms at right angles to each other (Fig -3A) connected to the main shaft through the opening struts (Fig -2) which enable the device to open and close when the central core shaft is moved using the control handle. In the closed position (Fig -3B) the four arms retract into the shaft of the catheter and do not protrude from the core catheter creating a smooth external surface. The cutting arms can be made of any rigid material like titanium or stainless steel that can be finely cut using mechanical equipments or laser. This is the most important movable part of the device. It is also important to ensure mechanical integrity of the device so that it does not break inside the blood vessel. This can be a single blade or multiple blades jointed at variable (1 mm to 5 mm) distances so that the device becomes malleable and trackable. The material used at the cutting end must be radio-opaque so that the opening and closing of the device can be visualized under fluoroscopy. The saw tooth configuration of the cutting edge is optional. This configuration make the cutting edge more efficient as a cutting tool.

The control end of the device is the proximal part of the device. The proximal end has the handle that is used to open and close the device (Fig -4). This is connected to the shaft that moves at the distal end and is in turn connected to the struts that open the cutting arms. The proximal end has a screw like mechanism that when rotated over a screw, moves the inner core shaft and in turn opens and closes the cutting arms. This screw like action makes the atherotome fully controllable. This also enables one device to open from 2 mm to 5 mm using the screw like mechanism.

The Shaft

The shaft of the device is made of a relatively non-shortening material so that the pull exerted by the wire on the cutting end is transmitted fully and not lost in the catheter shortening.

Some of the variations have been envisaged. One of them is detailed below:

The device can be modified into a simpler version where the open position is diamond shaped (Fig 5). Here the wire is pushed (instead of pulled by the handle) into the distal part so that the device opens it's arms. This simple model can be used to break herd calcium and advance the balloon or other devices. A saw tooth ^configuration (Fig -6) can be added to the cutting edge to make it more efficient as a cutting device. The moving and deploying mechanism remains the same and the control handle is also the same as for the main design.

The Novelty of the invention lies in that:

1. It is a Pure mechanical cutting device

2. It is a Non balloon based device

3. The device allows multiple diameters with one device (Allows gradual cutting and one device for all sizes)

4. The device offers Non inflating (screw) type of control (provides excellent

control over the process)

5. The device offers Saw tooth cutting edge

6. The device offers a simple Umbrella mechanics for opening and closing

The novelty and inventive steps lies the arrangement as disclosed herein.

In one embodiment a catheter atherotome for use in interventional cardiology in an artery having a distal end and a proximal end, a. A plurality of blades mounted at the distal end of the catheter in a_. winged configuration and spaced angularly apart from one another about a main longitudinal shaft with a central longitudinal core disposed within the said shaft, with associated struts connecting one end of each blade to the shaft and the other end to the core in such a way that longitudinal movement of the central core along the shaft in first direction selectively pulls out blades radially inwardly flat into alongwith the main shaft during the longitudinal movement of the core along the shaft in second direction, which second direction is opposite to first direction, b. A handle means disposed at the proximal end for. moving the core with respect to shaft to determine the longitudinal position thereby the pitch of blades, c. A screw means disposed at the proximal end for moving the core to determine the rotational position thereby the radial opening of the blades around the shaft and d. Wherein the said blades further define sharpened edges.

In another embodiment the winged configuration of the blades may be diamond configuration.

In another embodiment wherein the sharpened edges of blades may be saw tooth configuration.

In another embodiment wherein said core defines lumen means for receiving a guide wire extending through the core for guiding catheter atherotome in the said artery.

There are many variations possible with the above disclosure. All variations & modifications possible that will be understood by skilled persons is within the scope of this invention. Examples & embodiments have been provided for the purpose of understanding and shall not limit the scope of the invention.

Claims

CLAIMS:

1. A catheter atherotome for use in interventional cardiology in an artery having a distal end and a proximal end, a. a plurality of blades mounted at the distal end of the catheter in a winged configuration and spaced angularly apart from one another about a main longitudinal shaft with a central longitudinal core disposed within the said shaft, with associated struts connecting one end of each blade to the shaft and the other end to the core in such a way that longitudinal movement of the central core along the shaft in first direction selectively pulls out blades radially outwardly around the shaft into a cutting position and selectively pushes the blades radially inwardly flat into alongwith the main shaft during the longitudinal movement of the core along the shaft in second direction, which second direction is opposite to first direction, b. a handle means disposed at the proximal end for moving the core with respect to shaft to determine the longitudinal position thereby the pitch of blades, c. a screw means disposed at the proximal end for moving the core to determine the rotational position thereby the radial opening of the blades around the shaft and d. wherein the said blades further define sharpened edges.

2. The device as claimed in Claim 1 wherein the winged configuration of the

blades may be diamond configuration.

3. The device as claimed in Claim 1 wherein the sharpened edges of blades may be saw tooth configuration. The device as claimed in Claim 1 wherein said core defines lumen means for receiving a guide wire extending through the core for guiding catheter atherotome in the said artery.