WO1999066847A1

WO1999066847A1 - Atherectomy and angioplasty catheter

Info

Publication number: WO1999066847A1
Application number: PCT/FR1999/001510
Authority: WO
Inventors: Viên TRAN KHANH; Michel Bonneau; Hung Nguyen Xuan
Original assignee: Tran Khanh Vien; Michel Bonneau; Hung Nguyen Xuan
Priority date: 1998-06-23
Filing date: 1999-06-23
Publication date: 1999-12-29
Also published as: FR2779933A1; FR2779933B1

Abstract

The invention concerns a device for percutaneous transluminal angioplasty formed by a catheter (7) with adjustable head (3) enclosing a probe (2) provided with a head (3) for treating a vascular atheroma, the catheter (7) has, in the proximity of the probe (2) head (3), means for setting in place a pre-positioned endovascular prosthesis.

Description

CATHETER OF ATHERECTOMY AND ANGIOPLASTY

The present invention relates to the field of percutaneous translu inal angioplasty probes.

It is known to treat an occlusion of the artery with atheroma plaques, calcified using an atherectomy probe introduced into the arterial lumen using a catheter. Various systems of atherectomy are known in the prior art, in particular ultrasound probes, rotary burr, rotary blades, laser, water jet, ...

As an example of an ultrasound atherectomy probe, reference may be made to US patent US4870953. For atheromas, it is also known to use a balloon to dilate the stenosed walls.

It has also been proposed, in the prior art, to combine the two processing means on a single probe. PCT patent WO94 / 01047 proposes an ultrasound probe whose catheter includes an inflatable balloon, in order to allow the treatment of different types of atheromas.

It is also known that the various existing atherectomy systems have good flexibility allowing them to follow certain sinuosities of the arterial system to navigate to the stenosis ^' to be treated. However, this flexibility still has sufficient stiffness to prevent them from being used or from following all the windings. The existing systems result in fact from a certain compromise between the attack efficiency of the plate and the flexibility necessary for navigation. From experience we consider it necessary to make a catheter so the distal end can be oriented by an external command during its navigation. Atherectomy systems fitted with such a steerable head catheter thus have their field of application extended beyond the indications of the system without a steerable catheter. Thus it avoids the attack of the arterial wall by the head of atherectomy thanks to a possible repositioning of this head with this reorientation system.

After the arterial occlusion is removed by the atherectomy system, it is usual to reinforce the result, keeping the vascular wall open by means of a stent or stent. This stent is introduced using another catheter provided with an expansion means. Therefore, it is necessary to successively introduce two catheters, which multiplies the risks.

In order to remedy this drawback, the invention provides a device formed by an integrated catheter with an adjustable head for transluminal angioplasty, combining a stent delivery system and an atherectomy system (ultrasound, rotary burr, rotating blades, laser, water jet, ...). This device allows the deployment of said stent, immediately after recanalization by said atherectomy system without prior dilation operation with a balloon, different from the possible expansion balloon of the stent.

According to its meaning, the most general, the transluminal angioplasty device, according to the invention, is formed by a catheter with adjustable head surrounding a probe, provided with a head for treating arterial atheromas, characterized in that said catheter present, a distal orientable end actuated by an external device followed by a stent delivery means

Preferably, the catheter is a flexible multi-lumen catheter, having a steerable distal end and a proximal end and carrying outside of its distal surface, a stent delivery system with a stent or more prepositioned stents.

According to a first variant, the means for delivering the stent is formed by an expandable balloon by injecting a fluid through the catheter.

According to a second variant, the said catheter with orientable head has, at its distal end and close to the probe head, a delivery means, formed by a retractable sleeve for the installation of a self-expanding stent.

The present invention provides the following advantages: - Greater ease of navigation through the arterial system

- Increased safety for the patient, linked to a reduction in the number of repeated gestures, imposed by the successive introductions and exchanges of the various medical devices used during the intervention. Indeed, reducing the number of said gestures has the following advantages.

- Reduction in the duration of the intervention

- Reduction in the duration of exposure to X-rays for patients and operators

Decreased duration of ischemia and anesthesia for the operated patient

- Reduction of the risk of traumatic and hemorrhagic accidents possible - Reduction of the risks related to the infection for the operated

Decreased vasospasm, which helps limit the use of pressor drugs.

Advantageously, the transluminal angioplasty device comprises a probe head constituting a means of mechanical and / or physical ablation of the atheroma.

According to a particular embodiment, the probe is an ultrasonic probe. Advantageously, the catheter with orientable head makes it possible at any time to reorient the probe head during its attack in the atheroma using the external orientation control device. Advantageously, this catheter has, at its orientable distal end, close to the probe head, a stent delivery means and is pre-equipped with an expandable stent, said delivery means being controlled by the proximal end of the catheter. The invention makes it possible to reduce the number of micro-embolism accidents originating from thrombi detached from the pathogenic wall, thanks to the integration of the various operations. Indeed, in the case of the invention, one begins by recanalizing the artery occluded by the atherectomy system of the integrated catheter with adjustable head. Then, one deploys either the self-expanding stent or the stent mounted on a balloon. The usual prior bloating expansion operation is no longer necessary. This new technique, developed thanks to the integrated catheter, makes it possible to immediately block pathological tissues against the vascular wall, without giving them time to free themselves and to migrate downstream, which would have the consequence of causing distal embolisms.

The present invention also guarantees the reduction of the risks of elastic return.

One of the effects of the action of ultrasound, emitted by the ultrasound probe of ultrasound angioplasty, is to reduce the resistance of the biological tissues making up the stenosis, which makes them more easily compactable. This result has the effect of reducing the radial force necessary for the dilation of the vascular lumen. This property allows the stent to be placed directly after ultrasonic recanalization, without going through a prior balloon dilation. This property of reducing the pressure used during the delivery of the stent, makes it possible to reduce the aggression on the vascular wall, a frequent cause of restenosis, and can make it possible to facilitate the use of self-expanding stents, which currently have no strength. sufficient radial expansion in a number of cases. The ability to decrease the radial force improves the adhesion of a stent placed on a vascular wall. Indeed, it sometimes happens that the diameter of the dilation balloon, used prior to the placement of the stent, gives the dilated segment of the pathogenic artery, a diameter slightly greater than that of the deployed stent. With time and the movements of this so-called artery, the stent manages to leave spaces between the arterial wall and the metallic structure of the stent. These spaces are areas of swirling blood, which is a source of thrombosis. The present invention improves the adhesion of the stent to the vascular wall.

The integrated system according to the invention, by reducing the intervention time, makes it possible to improve the working conditions for the operators (reduction of the time spent under irradiation, stress ...) and the profitability of the technical platforms .

To facilitate understanding of the descriptions made in the text, the single figure, not to scale, has been attached. In this figure, identical references designate the same elements.

Balloon or dilation angioplasty is today a less invasive, controlled and recognized technique for recanalizing atheromatous arteries. The success rate, on the treated cases is of the order of 50% to 55%, taking into account the phenomena of restenosis. This restenosis rate is then between 45% and 50% of these cases. To reduce this rate of restenosis, the technique of placing an endoluminal prosthesis (stent) was introduced, which allows this so-called restenosis rate to be reduced to 20% of the cases treated. The combination of these two techniques (balloon angioplasty + stent placement) has obtained international consensus in the medical community.

In the case of total occlusions, or very tight occlusions, which do not allow the passage of the balloon, the combination proposed above cannot be applied. These cases then fall under bypass surgery, a heavy, traumatic and decaying technique.

To extend the application of the balloon angioplasty technique to these cases, atherectomy systems have been invented such as:

Rotablator

Rotating blades (rotablazor) Laser Water Jet Ultrasound

In summary, today, the best chances, to increase the reliability of recanalization, to decrease the rate of restenosis, impose to associate a technique of atherectomy followed by angioplasty by balloon and followed by the installation of a stent. The combination of techniques, mentioned above, requires precise sequencing of the operating procedures in these three techniques. Indeed, during these different successive operations:

We cannot change the order in the operating procedure

Only one operating instrument or medical device can be introduced at a time into the vascular lumen. Indeed, to perform one of the three gestures, we have to introduce into the arterial system a specific device, to do the work. When this work is finished, the device is extracted before introducing the instrument allowing to perform the next gesture. This leads to an increase in the handling of medical devices. This sequencing leads us to call this method of operation, the sequential method.

The multiple manipulations of the operating instruments linked to this sequential method, entail the risks of traumatic, hemorrhagic and infectious accidents. The present invention avoids these repeated manipulations.

In addition, with certain new generation stents (with shape memory, for example, etc.), it is quite possible to place them, without having to dilate the stenosis beforehand. Stents can be placed using devices that do not use delivery balloons. A special property of angioplasty probes percutaneous ultrasound is to allow a very great reduction in the inflation pressure of the dilatation balloon, pressure which goes from 10 bars approximately, to 3 bars approximately, for stenoses recanalized by ultrasound. It has been observed that there may be a mismatch between the diameter of the dilated stenosis and that of the bars of the stent placed, leaving spaces between the arterial wall and the bars or turns of said stent, for the passage of blood, source of thrombosis. The integrated catheter according to the present invention has many additional advantages. It makes it possible to reduce the number of manipulations of medical instruments and to eliminate the prior dilation operation due to their integration into said integrated catheter. In the particular case of ultrasound, the lower resistance to crushing of the tissues of the stenosis facilitates all the more the expansion of the stents, which can be deployed, in this case, at a pressure 2 or 3 bars instead of 10 to 12 bars. This low pressure makes the operation less traumatic for the arterial wall.

The deployed stent is intimately linked to the arterial wall, without leaving spaces that generate thrombosis.

All these improvements necessarily entail a lower cost for the operation.

As we will see later, the system using the integrated catheter, described by the present invention, makes it possible to treat cases of very tight occlusions, the only solution of which has been, until now, heavy bypass surgery.

In addition, the swiveling head of the integrated catheter allows this system to access difficult areas,

Procedure: 1) An approach is made according to the method

Seldinger, to set up an introducer. 2) From this route first, a navigation guide is brought to the site of the stenosis.

3) An angiography catheter is threaded on this so-called navigation guide, to be positioned in the stenosis vessel. An angiography makes it possible to control the state of said stenosis vessel.

4) The said navigation guide is then removed, leaving in place the catheter which was used for the angiography. This said guide is then replaced by a transfer guide, having more rigidity

5) Once the transfer guide is in place, the angiography catheter is removed, leaving said transfer guide in place

6) On this said transfer guide, a carrier guide catheter is then placed.

7) On this guide and guide guide catheter assembly, the integrated catheter described by the present invention is introduced, according to conventional catheterization techniques. 8) Recanalization or destruction of the atheroma plate is then carried out. with the atherectomy device (ultrasound probe or other).

Two situations can then arise:

If the stenosis presents a partial occlusion; the transfer guide is left in place and will guide the attack of the ultrasonic probe head through the stenosis. The swivel head catheter allows for greater ease of orientation during navigation and may allow reorientations of the atherectomy head during the attack of the stenosis. If the stenosis is total, the head of the ultrasound probe can be attacked without the guide. This is one of the advantages of ultrasound. Indeed, the ultrasonic probe, operating according to the longitudinal vibration mode, can create a light through the pathological tissue of the stenosis, while respecting the healthy fibrous tissue of the arterial wall. It remains inside the artery without being guided. The swiveling head of the catheter can allow attack path corrections, to avoid creating damage to the arterial wall.

In both cases, the ultrasound probe will dig a lumen through the stenosis, calcified or not, without damaging the arterial wall. The lumen hollowed out through the stenosis by the ultrasonic probe head has a diameter sufficient to allow passage of the catheter carrying the undeployed stent. Under these conditions, said stent, not deployed, can be positioned in this said lumen. Next, said stent is deployed in this so-called stenosis, the tissue resistance of which has been reduced by the ultrasonic treatment.

Ultrasound allows the recanalization of a partially or totally blocked artery, by calcified or not calcified atheroma plates. This recanalization is, thanks to the placement of stents, made durable.

The invention will be better understood on reading the description of nonlimiting exemplary embodiments, referring to the appended drawings where: FIG. 1 represents a sectional view of a first alternative embodiment; Figure 2 shows a sectional view of a second alternative embodiment; Figure 3 shows a partial sectional view of a third alternative embodiment.

A first embodiment of a device according to the invention is presented in FIG. 1.

The device consists of a flexible catheter (1) inside which, in a known manner, extends an ultrasound probe (2), the proximal end of which is equipped with a connector (4) for connection with a generator. ultrasound, and the distal end of which has a head (3) for treating atheroma.

The catheter (1) of the probe is surrounded by a second multi-lumen catheter (7) with an adjustable head (20), carrying a balloon (5) on the outside of its distal surface. inflatable, with a prepositioned stent (6). The balloon (5) communicates with one of the lumens of this external catheter (7). The proximal end of said multi-lumen catheter (7) with adjustable head (20) is connected to a means for injecting a fluid, to ensure the expansion of the balloon (5), for example, an inflation catheter (8) .

In known manner, lights of said multi-lumen catheter (7) must allow the passage of a guide, the passage of a wire of the control system of the adjustable head (20), the injection of liquids, such as contrast liquid , for example.

FIG. 2 represents an alternative embodiment of the device, distinguished by the additional presence of a dilatation balloon (30) placed between the orientable head (20) and the releasable stent (6). This additional balloon (30) makes it possible to dilate the part of the artery treated and recanalized by the atheroctomy head (3), before the stent is placed (6).

Another embodiment of a device according to the invention, corresponding to a variant not illustrated by a figure, is the following:

The catheter (1) of the probe is surrounded by a second multi-lumen catheter (7), carrying outside the surface close to its adjustable distal end, a stent delivery system with one or more pre-positioned self-expanding stents . Said delivery system is formed by a retractable sleeve which keeps said self-expanding compressed stents before they are released. The proximal end of said multi-lumen catheter (7) is connected to a means for removing said sleeve allowing the deployment of said self-expanding stents. The catheter also comprises a wire (45) for controlling the orientable head, for injecting liquids such as contrast liquids for example. This wire is fixed on the distal end of the catheter, at an eccentric lateral point (46) of the wall situated in front of a flexible zone (35).

This wire (45) can pass through the catheter (7) throughout its length. It can also exit the catheter behind the flexibility zone (35). Different variants of wire routing can be envisaged without departing from the scope of the invention.

An embodiment of the catheter with orientable head is shown in FIG. 3. On the basis of a reinforced cylindrical catheter (7) (metallic core), an asymmetry of rigidity is created at its distal end over a few centimeters in length. This asymmetry can be obtained by making several parallel slits (40 to 44), of appropriate depth and thickness. These slots (40 to 44) are made by sawing on the wall of the catheter, in order to weaken the catheter laterally and to create an asymmetry of the stiffness of the catheter allowing a controllable deformation. These notches (40 to 44) are made from 5 mm from the distal end. The depth of the slits is such that the tube remains cylindrical and allows navigation in the vascular system without deformation of the unprocessed catheter. The depth, spacing and number of notches (40 to 44) is determined experimentally or by calculation so as to reconcile the two following constraints: sufficient rigidity for the advance of the catheter during insertion and navigation in

1 artery; sufficient flexibility to allow the swiveling head to be oriented without excessive effort.

The width of these slits and a few tenths of a millimeter. The orientation of the head is controlled by a microfilm (45) of a cross section less than or equal to 1/10 mm attached near the end of the catheter before the first slit and on the side of the slits. This wire runs along the inside of the catheter to exit through a suitable opening at the proximal end of the catheter. A suitable mechanical system makes it possible to exert traction on this wire which will cause a change in orientation of the head of said catheter. A loosening of this wire allows the catheter to return to its original orientation.

The combination of a possible movement of the orientable head with the progression of the catheter in the canal lumen should make navigation easier. The wire (45) can be produced in the form of a flat wire, obtained by crushing a wire of circular section.

In another embodiment, the distal end and the machined part can be covered with a "soft tip".

FIG. 4 represents an alternative embodiment in which the distal end and the part presenting the notches (40 to 44) are covered by a flexible sleeve (50), for example a plastic skin known under the commercial name of "SOFT TIP ". This flexible sleeve (50) is welded at the two ends (51, 52) to the catheter (7), on either side of the section having the notches (40 to 44).

Claims

1 - Transluminal angioplasty device formed by an integrated catheter with an adjustable head surrounding a probe (2) provided with a head (3) for treating vascular occlusions, characterized in that the catheter (7) presents from its distal end (20), an orientable head (3) followed by means for installing a prepositioned vascular stent, all close to the head (3) of the probe (2).

2 - Transluminal angioplasty device according to claim 1 characterized in that the integrated catheter (7) is a flexible multi-lumen catheter (7), having an orientable distal end (20) and a proximal end and carrying, at the outside its distal surface, a stent delivery system (6) with one or more prepositioned stents (6).

3 - Transluminal angioplasty device according to claim 1 or 2 characterized in that the means for placing a stent (6) is formed by a balloon expandable by the injection of a fluid through the catheter (7).

4 - Transluminal angioplasty device according to at least one of the preceding claims, characterized in that the head (3) of the probe (2) constitutes a mechanical and/or physical ablation means.

5 - Transluminal angioplasty device according to at least one of the preceding claims characterized in that the probe (2) is an ultrasound probe (2).

6 - Transluminal angioplasty device according to claim 1 characterized in that the catheter (7) has, from its distal end (20), an orientable head (3) close to the head (3) of the probe (2), a means of placing endoprostheses pre-equipped with one or more stents

(6) expandable, said installation means being controlled from the proximal end of the device.

7 - Angioplasty device according to claim 1 characterized in that the catheter (7) integrated presents, from its distal end (20), an orientable head (3) close to the head (3) of the probe (2), an installation means formed by a retractable sleeve for the installation of a self-adhesive stent (6). -expandable.

8 - Angioplasty device according to at least one of the preceding claims characterized in that the catheter (7) has a distal flexibility zone (35), and a traction wire (45) fixed eccentrically at a point ( 46) in front of said flexibility zone (35).

9 - Angioplasty device according to claim 8 characterized in that the flexibility zone is formed by a cylindrical section having a plurality of lateral notches (40 to 44).

10 - Angioplasty device according to at least one of the preceding claims characterized in that it further comprises a means (30) for angioplasty placed between the adjustable head (20) and the stent placement system (5 , 6).