MXPA98007334A - Dilating catheter for the introduction of "stents" expandib - Google Patents

Abstract

This invention relates to a dilating catheter for introducing and inserting expandable stents comprising an inflatable balloon, which is applied to a section of the distal end of the catheter and which can be wound, if empty in said section to be applied therearound a " stent "contracted. The outer surface of the balloon is made rough by the supply of a material or a deformation in order to offer greater interference and grip to the stent contracted tightly around

Description

DILATING CATHETER FOR THE INTRODUCTION OF "STENT3" EXPANDIBLE3 The present invention belongs to the instruments for the introduction and mechanical expansion of "stents" in the channels or cavities of a living body, whether human or animal. The "stents" are tubular molds that are made of biocompatible materials and are contracted during their introduction and then they are dilated for insertion into the desired channel or cavity. Some types of "stents" mechanically dilate, and for their insertion they require the use of an expandable element disposed along the introducer and dilatable instrument inside the "stent". As an instrument for the introduction of mechanically dilating stents, a catheter can also be used having an inflatable balloon at its distal end of the type as hitherto can be used, e.g., to dilate arterial channels or other cavities in a living body. Accordingly, for the insertion operation, the balloon, vacuum, is tightly wound around a corresponding area of the catheter, and the stent, in turn, is tightly arranged around the balloon so that it remains fixed there during the introduction inside a cavity. However, the requirements of a catheter for simple dilation of channels or cavities are most often incompatible with those of a catheter for the positioning of a stent, which is why specific catheters would be necessary for one or another operation. . A dilating catheter, for example, for angioplasty procedures, or the like, should have a small diameter, a highly resistant balloon, and a low coefficient of surface friction. On the other hand, a catheter for the positioning of "stents" must have a remarkable friction at least in the balloon, it must be made of a material with a moldable surface that is adapted to the interior of the closed, ie, contracted stent, and must have a diameter of the balloon, when closed, ie, around the catheter, at least slightly larger than the internal diameter of the closed stent. All this is to interfere with the "stent" and retain it, preventing its loss during insertion into a channel or cavity.

In other words, the slippery surface of the balloon can be a cause of the loss of the stent. In addition, a diameter in the area of the catheter, including the closed balloon wound there, that is smaller than the internal diameter of the closed stent that is applied therein can cause: a so-called overlap resulting from a corrugation and an overlap of some parts of the "stent" with possible deformation of its structure, if the "stent" is too tightly contracted to adhere to such a zone; or - improper fixation of the stent with the possibility of losing it during the introduction if the stent, although properly and correctly closed, does not adhere to the outer surface of the catheter plus the closed balloon. Starting from these representative premises of the state of the art, the purpose of the present invention is to provide a valid solution to the problems mentioned above and to correspondingly provide an improved dilating catheter at the level of the inflatable balloon, so this constitutes a valid, grip positive to interfere with and retain the "stent" that is applied there from the inside, to avoid the loss of the latter during the introduction phase without having, however, an effect on the dilatability of the balloon when the stent is expanded and released This purpose is achieved with a dilating catheter according to claim 1. In practice, the outer surface of the balloon is roughened by a coating of material having a higher coefficient of friction and by a deformation or embossing of the wall of said balloon for an increase in the friction and / or diameter of the balloon, so that the "stent" is in a better anchoring position when it is in its contracted position around the balloon. Further details of the present invention will be more apparent in the description given below with reference to the accompanying drawings, in which: Figure 1 shows a part of a balloon catheter modified according to the present invention and with a "stent" contracted around the empty ball; Figure 2 shows a similar view of the catheter of Figure 1, but with the balloon and the stent expanded; and Figure 3 shows another way of roughening the outer surface of the balloon. In said drawings, the catheter is indicated generally by 11 and has, in the known manner, an inflatable balloon 13 in its distal end section 12. According to the present invention and according to a first embodiment as shown in the Figures 1 and 2, a layer 14 of a material having a high coefficient of friction or of roughening this surface is spread on the outer surface of the balloon, at least a section of its length. The material for the formation of this surface layer 14 can be a silicone, gel, or other biocompatible product that is chemically bonded by vulcanization or by another suitable method with the material forming the balloon. Accordingly, the scattered layer 14 contributes to an increase in the outer diameter of the balloon for its greater interference with the interior of a stent 15, which is tightened around it, and in addition, increases the friction of the balloon surface. way to better retain the "stent" against the longitudinal sliding and therefore against the loss during the introduction into a channel or cavity.

A similar result can be achieved without the spreading of a material on the outer surface of the balloon but by means of a deformation or corrugation of the wall of said balloon, eg, by means of drawing or embossing 16 as shown in Figure 3. Figure 1 shows the condition of the balloon, which is empty and is wound around the catheter, and the "stent", which is contracted around it, while Figures 2 and 3 show the condition of expansion of the balloon and dilatation of the balloon. "stent" by releasing it, when the balloon has an outer scattered layer and a corrugated wall, respectively.

Claims (4)

1. Dilating catheter for introducing and inserting expandable stents comprising an inflatable balloon, which is applied in a distant end section of the catheter and which can be rolled, if empty, in the said section so as to be applied there around a "stent" contracted, characterized in that the outer surface of the balloon is roughened by means of the supply of a material or a deformation to offer greater interference and grip to the stent tightly contracted around it.

A dilating catheter according to claim 1, wherein a layer of material having a high coefficient of friction, which is chemically bonded by vulcanization or another method with the surface of said balloon to be coated, is applied to the outer surface of the ball.

A dilating catheter according to claim 2, wherein the layer of the material increases the outer diameter and the friction of the balloon surface, and the material can be a silicone, a gel or another biocompatible product.

4. Dilating catheter according to claim 1, wherein the balloon wall is deformed, so that it has corrugations, embossing, or embossing to interfere with the "stent" applied therein.