Patent Application
20100137793
The present invention relates to a balloon catheter device for use in the aspiration of thrombi and other particulate matter from body passages. More specifically, the presently-disclosed invention is a catheter device comprising an inner balloon that adopts a spiral conformation upon inflation, and a second, sleeve-like outer balloon.
The inappropriate and undesirable formation of blood clots intravascularly may have severe pathological consequences, as a consequence of the disturbance of blood flow to vital organs and tissues such as the heart muscle and brain. In extreme cases, total occlusion of the afferent arteries may lead to ischemic damage which, in the case of the heart, may manifest itself clinically in the form of myocardial infarction. Similarly, the local production of thrombi in the cerebral vessels or the deposition therein of thrombotic emboli may lead to cerebral infarcts. In both cases, serious morbidity and death are common consequences. It has been estimated, for example, that emboli arising from atherosclerotic plaques of the carotid artery cause approximately one quarter of the 500,000 strokes that are recorded annually in the United States.
Several different medical and surgical approaches aimed at removing thrombotic and embolic material from blood vessels have been proposed and attempted. One such approach requires the injection of thrombolytic agents. Alternatively or additionally, a variety of balloon catheter systems have been used to both expand blood vessels that have become narrowed due to thrombus formation or deposition and, in some cases to collect detached thrombotic material and remove same from the body.
One example of a balloon catheter system that has been designed for use in removing thrombotic material and other intravascular particulate matter from the body is that disclosed in U.S. Pat. No. 4,762,130 (Fogarty). While several different embodiments of the catheter are described in the patent, a feature common to all of these embodiments is that a balloon is advanced into the region of the thrombus to be treated and then expanded into a helical or spiral configuration, thereby engaging said thrombus within the spiral channels of the inflated balloon. The spiral balloon is then withdrawn from the body with the thrombus still attached thereto. A particular disadvantage of this prior art system is that the catheter is usually inflated distally to the thrombus (or other particulate matter) and is then pulled back in order to facilitate collection of the thrombotic material by the balloon. This procedure can be traumatic for the blood vessel. Furthermore the balloon does not always completely seal the vessel and some of the debris escapes into the blood stream and is not removed. A further key problem associated with this system is the fact that during balloon inflation, the blood flow through the vessel is blocked.
It is a purpose of the present invention to provide a balloon catheter system that may be used for trapping and retaining particulate matter and safely removing said matter from the body.
It is a further purpose of the invention to provide a balloon catheter system that overcomes the problems and disadvantages associated with prior art devices.
Further objects and advantages of the present invention will become apparent as the description proceeds.
The present invention is a balloon catheter device that uses a spiral balloon as an aspiration device. The device is composed of a catheter fitted with two balloons, one inside the other.
The present invention is primarily directed to a balloon catheter system comprising one or more conduits to which is/are attached an inner compliant balloon having a non-helical shape in its deflated state and an outer non-compliant or semi-compliant balloon, such that said inner balloon is enclosed by said outer balloon, and wherein the inner balloon is constructed such that upon inflation, said inner balloon is capable of adopting a spiral or helical conformation. The catheter system is further characterized in that the outer balloon is perforated by a first set of pores or openings along most or all of its surface, and is further perforated by a second set of pores or openings in the regions of the proximal neck or taper of said outer balloon, wherein the pores or openings of said second set are significantly fewer in number and larger in diameter than said first set.
For the purposes of the present disclosure, the terms “proximal” and “distal” are defined from the physician's (or other operator's) perspective. Thus, the term “proximal” is used to refer to the side or end of a device or portion thereof that is closest to the external body wall and/or the operator, while the term “distal” refers to the side or end of a structure that is in an opposite direction to the external body wall and/or operator.
In one preferred embodiment the distal and proximal necks of the inner and outer balloons are attached to a single catheter conduit. In another preferred embodiment, the distal necks of the inner and outer balloons are attached to one catheter conduit while the proximal necks thereof are attached to a second conduit, wherein said first and second conduits are arranged such that at least a portion of the shaft of one of the conduits is disposed within the lumen of the other conduit.
In another aspect, the present invention is directed to a method for removing particulate matter from a body passage in a patient in need of such treatment, comprising the steps of:
In the above-described method, the phrase “in the region of the particulate matter to be removed” is intended to convey the meaning that the balloons may be located at any of the following locations: entirely proximal to the debris, entirely distal to the debris, entirely within the region of the debris or partially within and partly without (distal or proximal to) the region of the debris.
In a preferred embodiment of the above-disclosed method, the particulate matter to be removed is thrombotic material.
In another embodiment of the device of the invention, said device further comprises a layer of an absorbent material surrounding the inner balloon in an annular manner. While any suitable absorbent material may be used for this purpose, in a preferred embodiment, said material is selected from the group consisting of steel wool and fibrous polymers. Unlike the embodiments of the device described hereinabove, the presently-disclosed device does not have an open spiral channel when the inner balloon is inflated. Rather, said spiral channel is obliterated by the present of the absorbent material. Thus, rather than trapping particulate matter within the spiral channel as described above, in the presently-disclosed embodiment, the thrombotic debris and/or other matter is absorbed within the pores of the absorbent layer.
All the above and other characteristics and advantages of the present invention will be further understood from the following illustrative and non-limitative examples of preferred embodiments thereof.
The invention is based on the use of an inner compliant balloon which is fitted over a conduit and covered with a second, outer non-compliant or semi-compliant balloon. In its deflated state (
The inner balloon can be made from one material. Alternatively, the inner balloon may be constructed from two or more different materials, thereby producing a non-uniform spiral balloon upon inflation. Suitable materials for use in constructing the inner balloon include (but are not limited to): silicones and thermoplastic elastomers (TPEs).
The inner balloon 12 is bound at two points to a rigid or semi-rigid conduit 10 which is threaded through the balloon. Since the balloon is made of a compliant material it elongates during inflation. However, as the inner balloon 12 is bound at both its ends, its longitudinal elongation is restrained. Provided certain balloon-related design parameter criteria are met (as will be discussed hereinbelow), said inner balloon 12 will then buckle and assume a spiral shape as shown in
It has been unexpectedly found by the present inventors that certain fundamental conditions need to exist in order for the compliant, inner balloon of the present invention to adopt a spiral or helical shape when inflated. These may be summarized as follows:
Thus, only when the above conditions are met will a compliant balloon adopt a spiral conformation upon inflation. Examples of various compliant balloons and their ability to adopt a spiral conformation are summarized in the Example provided hereinbelow.
Using different wall thicknesses or different materials the shape of the helix and the inflation sequence can be controlled. In this regard, the inventors have unexpectedly found that the ratio between the diameter of the inner balloon in its unexpanded state, the length of said balloon and the thickness of its wall is an important determinant of the ability of the compliant inner balloon to expand from a tubular shape into a spiral or helical conformation. In one preferred embodiment, for example, it has been found that a compliant balloon having a length of 30 mm, an outer diameter of 1 mm and a wall thickness of 0.25 mm readily adopts a spiral conformation upon inflation, provided that both ends of said balloon are bound to a rigid conduit.
Typically, the inner balloon will have a length in the range of 15mm to 50 mm and a wall thickness in the range of 100 micron to 400 micron. It should be emphasized that the preceding dimensions (and all other dimensions that appear herein) are exemplary values only, and should not be construed as limiting the size of the presently-disclosed device in any way.
The inner, spiral balloon 12 in its inflated state creates a spiral channel 17 surrounding it, which allows free flow through the channel. The shape and size of the cross-section of the spiral channel 17 can be varied from a very small cross-section area (when the balloon is fully inflated,
The spiral balloon is covered with a non-compliant or semi-compliant balloon which is bound to the same shaft as the spiral balloon.
The outer balloon may be constructed of any suitable non-compliant or semi-compliant material, including (but not limited to): nylon, Pebax, polyurethane and polyethylene terephthalate (PET).
The outer balloon is perforated along most of its lateral surface by a first set of holes or pores 16 (
The general embodiment of the balloon catheter of the present invention that is described hereinabove and depicted in
In addition, various catheter tubes having a particularly small cross-sectional profile may be used to mount the spiral-forming balloon of the present invention. In one preferred embodiment, the catheter is constructed of a single-lumen stainless steel tube with a distally assembled spiral balloon (
The aforementioned spiral-forming balloon is attached at its ends to the distal portion of the hypotube (in a non-spiral, conventional manner) by means of thermo-bonding or adhesive technology.
In a variant of this embodiment, as shown in
In a further reduced cross-section variant, shown in
The conduits used to construct the catheter device of the present invention may be made of any suitable material including (but not limited to) a biocompatible polymer such as polyurethane or nylon or PET, or a biocompatible metal such as stainless steel, and may be manufactured utilizing conventional methods, such as extrusion and laser cutting. The diameter of the conduits is generally in the range of 0.5-2.0 mm, and their length is generally in the range of 100-2000 mm.
The compliant inner balloon may be inflated by introducing a pressurized inflation media via an inflation fluid port that is in fluid connection with a source of pressurized media and a pumping device or syringe. In the case of a single conduit catheter, the inflation media passes through openings in the wall of the catheter shaft located between the proximal and distal attachment points of the balloon. In the case of a dual (inner-outer) conduit conformation, as described above, the inflation media passes via an inflation fluid lumen formed between the inner wall of the outer conduit and the outer surface of the inner conduit.
Typical Procedure for Using the Balloon Catheter of the Present Invention:
By way of further explanation, it should be noted that the filtering and trapping function of the outer balloon mentioned and described in steps 2 and 3, above, is related to the size of the pores formed along most of the surface of the outer balloon (“small pores”), as well as the size of the larger pores situated at the proximal neck of the outer balloon (“large pores”). Thus, particulate matter having an average diameter less than the average diameter of the large pores will be able to enter the space between the inner and outer balloons. Any particles larger than the size of these pores will not be able to enter into that space. Once inside the space between the inner and outer balloons, and following the further expansion of the inner balloon and blockage of the large pores described in step 3, above, any particles smaller than the small pores will be squeezed out through said small pores and thereby returned to the bloodstream. Conversely, all particles larger than the small pore diameter will be retained in the space between the outer and inner balloons and ultimately removed from the body together with the catheter. It will therefore be appreciated that the outer balloon performs the following three key functions:
The pressure in the balloon after partial inflation to a first expanded state (as described in step 2, above) is in the range of 0.5 to 10 atmospheres.
All of the abovementioned parameters are given by way of example only, and may be changed in accordance with the differing requirements of the various embodiments of the present invention. Thus, the abovementioned parameters should not be construed as limiting the scope of the present invention in any way.
The following table summarizes certain key parameters of a series of different compliant balloons which were bound at both ends to a rigid catheter (diameter 0.3 mm). In the cases in which a spiral conformation was not achieved following inflation with water, this fact is mentioned in the ‘comments’ column of the table:
It will be seen from the proceeding table that only the balloons characterized by having certain structural parameters (e.g. length, diameter, material etc.) are capable of adopting a spiral conformation upon inflation.
While specific embodiments of the invention have been described for the purpose of illustration, it will be understood that the invention may be carried out in practice by skilled persons with many modifications, variations and adaptations, without departing from its spirit or exceeding the scope of the claims.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/IB2008/051160 | 3/27/2008 | WO | 00 | 1/14/2010 |
| Number | Date | Country | |
|---|---|---|---|
| 60920145 | Mar 2007 | US | |
| 60978122 | Oct 2007 | US | |
| 61038795 | Mar 2008 | US |
