FIELD OF THE INVENTION

The present invention generally relates to medical devices and methods for performing procedures within a lumen of a vascular system of a patient, and more particularly, to devices and methods for performing a procedure with a balloon guide catheter within a vascular system, such as treating ischemic strokes, and blocking or restricting blood flow for other treatment or diagnostic purposes.

BACKGROUND

Various designs of medical catheters have been previously provided for performing a variety of medical procedures, including interventional therapy, drug delivery, diagnosis, perfusion, and the like. In general, medical catheters are used by introducing the catheter through an entry site of a patient and into the vascular system of the patient, such as a vein or artery. The catheter is advanced from the entry site by guiding and pushing the catheter through the vascular system to a target site for performing a therapeutic and/or diagnostic medical procedure.

An example of one type of intravascular catheter is a balloon catheter which includes an elongated tubular member and a balloon affixed to the tubular member, for example, to a distal portion of the tubular member or other suitable location. The tubular member includes an inflation lumen extending from a proximal end of the tubular member to the balloon for injecting fluid into the balloon to inflate the balloon. Various types of balloon catheters have been previously disclosed for performing a variety of different medical procedures. For instance, balloon catheters for diagnosing and treating neurological disorders, such as ischemic stroke, is disclosed in U.S. Pat. No. 6,638,245 (the '245 patent), the disclosure of which is fully incorporated herein.FIGS. 10A and 10Billustrate a prior art balloon guide catheter150, as disclosed in the '245 patent. The balloon catheter150comprises an outer tubular member170and an inner tubular member172within the outer tubular member170. The balloon catheter150has an inflatable balloon160disposed on the distal end of the outer tubular member160. The annular space between the outer tubular member170and the inner tubular member172forms a fluid supply lumen158for inflating the balloon160. The balloon catheter150is advanced to a target site within the vascular system of a patient through an introducer sheath. Once in place, treatment catheters may be advanced to the target site through the working lumen152of the inner tubular member172. Accordingly, the prior balloon catheters, such as the balloon catheter150, required at least three catheter shaft thicknesses (the combined thicknesses of the outer tubular member170, the inner tubular member172and the introducer sheath). Thus, the prior balloon catheter must accommodate three catheter shafts, which can restrict the diameter of the working lumen in order to make the outer diameter of the balloon guide catheter small enough to fit into the vessels of a vasculature system, especially when used small vessels such as the neurovascular system.

The use of balloon catheters in the neurological vasculature presents a number of catheter design challenges. For one, the blood vessels in the brain are typically very small in diameter, as small as several millimeters or less, requiring that a catheter advanced into these blood vessels have an outside diameter as small as one French (0.33 mm). Furthermore, the brain vasculature is highly tortuous, requiring that a neurological catheter be very flexible, especially at the distal end, to travel through and conform to the tortuous path. Also, the blood vessels of the brain are quite fragile, so a neurological catheter must have a smooth, non-traumatic periphery.

Balloon catheters generally require preparation prior to use in advancing the catheter into the vasculature of a patient by purging air out of the catheter. As described above, a balloon catheter typically has an elongated tube and an inflation lumen. In some cases, a balloon catheter may also have multiple tubes (e.g., concentric tubes with an inner tube disposed within an outer tube). Each of these structures, including the tube(s), inflation lumen, and balloon must be purged of air with a fluid (e.g., saline) prior to advancing the catheter through the vasculature of the patient to prevent air from being introduced into the patient which can cause embolisms or other trauma in the patient. However, due to the closed-end fluid path from the inflation lumen to the balloon, and in many cases, within the tube(s) of the catheter, it is difficult and very time-consuming to purge all of the air from system. It is also difficult to determine when all of the air has been purged from the catheter because of the closed-end fluid paths. As a result, purging the air from prior balloon catheters during preparation for surgery often takes up to 15 minutes, and even then, the purging is not always successful.

SUMMARY

The present invention is directed to a balloon guide catheter having an innovative configuration which allows for faster preparation and more effective purging of air within the catheter (and filling the catheter with fluid, such as saline) than previously known balloon catheters. The presently disclosed balloon guide catheter is useful for insertion and positioning of therapeutic devices within a vascular system of a patient. For instance, the balloon guide catheter is particularly useful in imaging, diagnosing and/or treating blockages of a blood vessel, such as coronary occlusion or ischemic strokes. An ischemic stroke is caused by the blockage of a blood vessel in the brain, either by the narrowing of the blood vessel or presence of an embolus (e.g., a thrombus, or other abnormal material in the blood vessel). The balloon guide catheter of the present invention is also particularly well-suited for use in the neurological vasculature because it can be adjusted to have a more flexible distal end.

As explained above, balloon catheters typically require preparation of purging air from the system before advancing the catheter into the vasculature of a patient. The balloon guide catheter of the present invention is adjustable from a purging configuration in which the lumens of the tubular members and inflation lumen for inflating the balloon have an open-ended fluid path and an inflation configuration in which the inflation lumen is sealed so that the pressurized fluid can be injected into the inflation lumen to inflate the balloon.

In a first embodiment, a balloon guide catheter according to the present invention comprises an elongated, flexible, tubular outer member having a proximal portion, a distal portion, and an outer member lumen extending there between. The outer member lumen is in communication with a distal opening of the outer member. An elongated, flexible, tubular inner member is disposed at least partially within the outer member lumen such that an outer surface of the inner member and an inner surface of the outer member together define an annular fluid path between the inner member and the outer member. The inner member may be a delivery/treatment catheter. The inner member has a proximal portion, a distal portion, and an inner member lumen extending there between. The inner member lumen is in communication with a distal opening of the inner member.

A balloon is secured to the outer member. The balloon can be secured to any suitable portion of the outer member, including but not limited to the distal portion. The balloon comprises an elastomeric member having respective proximal and distal ends. The proximal and distal ends of the balloon are secured to and circumferentially around an outer surface of the distal portion of the outer member such that an inner surface of the elastomeric member and an outer surface of the outer member define an inflatable balloon interior. The outer member has one or more passages through a wall of the outer member that form a fluid pathway between the annular fluid path and the balloon interior.

An elastomeric tubular seal is disposed circumferentially around the outer member distal of the one or more passages through the wall of the outer member. For example, the tubular seal may be disposed circumferentially around the inner surface of the distal portion of the outer member, or other suitable sealing configuration. The seal may be secured proximal to the distal end of the outer member. The seal is configured to form a fluid-tight seal between the inner surface of the outer member and the outer surface of the inner member, such that it seals the annular fluid path when the inner member is in a sealing position.

The inner member is movable longitudinally relative to the outer member from a non-sealing position in which the distal portion of the inner member is positioned proximal of the seal, and a sealing position in which the distal portion of the inner member contacts the seal thereby sealing the annular fluid path at the location of the seal. In other words, the inner member can telescope within the outer member between the sealing position and the non-sealing position. The relative movement may be accomplished by moving the inner member, or by moving the outer member, such that there is longitudinal relative movement between the inner member and the outer member.

Accordingly, as the annular space between outer member and the inner member form the inflation lumen for the balloon, the balloon guide catheter of the present invention only requires two shafts, and therefore only two shaft thicknesses, to perform the same functions as the prior art balloon catheter having three shafts (as described above). This provides a very advantageous space efficiency, allowing the inner working lumen of the balloon guide catheter to be larger than previously disclosed balloon catheters, for a given outer diameter of the balloon guide catheter.

In another aspect of the balloon guide catheter, the seal and the inner member may be configured such that the inner member may be moved distally through the seal such that the distal portion of the inner member is positioned distally of the seal, while the seal continues to seal the annular fluid path. This movement can occur outside the body or in tortuous vasculature. In this way, the distal portion of the inner member may extend distally past the distal end of the outer member and the balloon, thereby providing a more flexible distal end of the guide catheter assembly. This can be useful in guiding the catheter through the vascular system of the patient.

In another aspect of the present invention, when the inner member is in the non-sealing position (i.e., when the distal portion of the inner member is positioned proximal of the seal), air may be purged from the balloon guide catheter by introducing pressurized fluid through the respective outer member lumen and inner member lumen such that fluid flows through the lumens and fluid paths of the catheter and out through the inner member distal opening and the outer member distal opening. More specifically, air is purged from one or more of the outer member lumen, inner member lumen, annular fluid path, one or more passages, and balloon interior, respectively, by introducing pressurized fluid through the respective outer member lumen and inner member lumen such that fluid flows through the one or more of the outer member lumen, inner member lumen, annular fluid path, one or more passages, and balloon interior and out through the inner member distal opening and the outer member distal opening. This allows an open-ended flow path for introducing fluid into the catheter to purge air from the catheter. Hence, a user can confirm that air has been successfully been purged from the catheter by observing fluid flow out through the inner member distal opening and the outer member distal opening.

In still another aspect, when the inner member is in the sealing position, pressurized fluid introduced into the proximal portion of the outer member lumen flows through the annular fluid path and the one or more passages, respectively, into the balloon interior to thereby inflate the balloon. The seal is located distal of the inflation passages in the wall of the outer member. Hence, when the inner member is in the sealing position, the annular fluid path is sealed at a location distal of the inflation passages such that pressurized fluid injected into annular fluid path at the proximal portion of the outer member injects pressurized fluid into the balloon through the inflation passages.

Another embodiment of the present invention is directed to a method of using the first embodiment of the balloon guide catheter. The method comprises preparing the balloon guide catheter for insertion into the vascular system of the patient by purging air from the guide catheter with the inner member positioned in the non-sealing position. The inner member may be pre-positioned in the non-sealing position, or the inner member may be moved relative to the outer member to position the inner member in the non-sealing position. Air is purged from one or more of the outer member lumen, inner member lumen, one or more passages, annular flow path and balloon by introducing fluid through the inner member lumen and outer member lumen and observing fluid flowing out through the inner member distal opening and the outer member distal opening. When fluid is observed flowing out of the inner member distal opening and outer member distal opening, without air bubbles, the user can be assured that the balloon guide catheter has been purged of air.

The balloon guide catheter is inserted into the vascular system of the patient. As described herein, the balloon guide catheter may be inserted through an entry incision into an entry blood vessel, such as the inferior vena cava or femoral artery near the groin. The inner member and outer member are then advanced through the vascular system to position the balloon at a treatment site. The inner member and outer member may be advanced simultaneously, or separately, and at the same rate or different rates.

With the balloon positioned at the treatment site, the balloon is inflated. With the inner member positioned in the sealing position, the balloon is inflated by introducing fluid into the outer member lumen such that the fluid flows through the annular fluid path, through the one or more passages, and into the inflatable balloon interior. The balloon may be inflated within the blood vessel such that the balloon seals the blood vessel. This isolates the blood vessel downstream of the balloon from the flow of blood. A treatment procedure, such as imaging, embolus removal, intravascular device implantation, or the like may then be performed. For example, an imaging catheter may be inserted through the inner member and advanced past the distal end of the inner member to image the blood vessel or surrounding tissue. In the case of removing an embolus, such as in the treatment of an ischemic stroke, an embolus removal device may be inserted through the inner member, and advanced past the distal end of the inner member to grasp or otherwise capture the annulus, and remove the embolus from the blood vessel.

In additional aspects, the method may include the steps of moving the inner member from the non-sealing position to the sealing position, and/or from the sealing position to the non-sealing position.

In yet another aspect of the method, the inner member may be moved relative to the outer member such that the distal portion of the inner member extends through the seal and beyond a distal end of the outer member. This provides a more flexible tip to the balloon guide catheter for guiding and advancing the catheter through the vascular system. The inner member may be advanced to extend the distal portion of the inner member beyond the distal end of the outer member before or during the steps of inserting the inner member and outer member into the vascular system and advancing the inner member and outer member through the vascular system. The inner member may be advanced to extend the distal portion of the inner member prior to or after inflating the balloon while not impacting the balloon. The inner member may be advanced proximal to the seal to allow for a fast deflation of the balloon and completely removed from the vasculature while leave the outer member in place.

A second embodiment of a balloon guide catheter according to the present invention is similar to the first embodiment described above, except that the seal is disposed circumferentially around an outside surface of the distal portion of the inner member, instead of on the inside surface of the outer member. In the second embodiment, the balloon guide catheter comprises an elongated, flexible, tubular outer member having a proximal portion and a distal portion, and an outer member lumen extending therebetween. The outer member lumen is in fluid communication with a distal opening of the outer member. An elongated, flexible, tubular inner member is disposed at least partially within the outer member such that an outside surface of the inner member and inside surface of the outer member together define an annular fluid path. The inner member has a proximal portion, a distal portion, and an inner member lumen extending therebetween. The inner member lumen is in communication with a distal opening of the inner member.

A balloon is secured to the outer member, for example, at the distal portion of the outer member. The balloon comprises an elastomeric member having respective proximal and distal ends secured to and circumferentially around an outer surface of the distal portion of the outer member such that an inner surface of the elastomeric member and outer surface of the outer member define an inflatable balloon interior. The outer member has one or more passages through a wall of the outer member that form a fluid pathway between the annular fluid path and the balloon interior thereby inflating the balloon;

An elastomeric, tubular seal is disposed circumferentially around an outside surface of the distal portion of the inner member. The seal is configured to form a fluid tight seal between an inside surface of the outer member and the outer surface of the inner member.

The inner member is movable longitudinally relative to the outer member from a non-sealing position in which the seal is positioned distal to the outer member distal opening, and a sealing position in which the seal is positioned within the outer member lumen such that the seal contacts the inner surface of the outer member thereby sealing the annular fluid path. Said another way, the inner member can telescope within the outer member between the non-sealing position and the sealing position.

In another aspect of the second embodiment of the balloon guide catheter, the inner member may further include a distal stop on a distal end of the inner member located distal of a distal end of the outer member such that the stop prevents the distal end of the inner member from being moved proximally past the distal end of the outer member.

In still another aspect of the second embodiment, the seal and inner member are configured such when the inner member in the non-sealing position, air may be purged from one or more of the inner member lumen, outer member lumen, annular fluid path, one or more passages, and balloon by introducing fluid through the one or more of the inner member lumen outer member lumen, annular fluid path, one or more passages and balloon and out through the inner member distal opening and the outer member distal opening.

In still another feature of the second embodiment, the seal and the inner member are configured such that when the inner member is in the sealing position, fluid introduced into the outer member lumen flows through the annular fluid path, through the one or more passages and into the inflatable balloon interior, thereby inflating the balloon.

In still another aspect, the seal and the inner member may be configured such that at least a part of the distal portion of the inner member may be advanced distally past a distal end of the outer member to form a flexible, distal guide portion of the guide catheter. For example, a length may extend past the distal end of the outer member and can be selected by the physician on a case-by-case basis, such as a length of about one, two, three, four or more times a length of the balloon.

Another embodiment of the present invention is directed to a method of using the second embodiment of the balloon guide catheter. The method is similar to the method of using the first embodiment, except that the process of moving the inner member between the sealing and non-sealing positions is slightly different. The method comprises preparing the balloon guide catheter for insertion into the vascular system of the patient by purging air from the guide catheter with the inner member positioned in the non-sealing position, i.e., the seal positioned distal of the outer member outlet. The inner member may be pre-positioned in the sealing position, or the inner member may be moved relative to the outer member to position the inner member in the sealing position. Air is purged from one or more of the outer member lumen, inner member lumen, one or more passages, annular flow path and balloon by introducing fluid through the inner member lumen and outer member lumen and observing fluid flowing out through the inner member distal opening and the outer member distal opening. When fluid is observed flowing out of the inner member distal opening and outer member distal opening, without air bubbles, the balloon guide catheter has successfully been purged of air.

The balloon guide catheter is inserted into the vascular system of the patient. As described herein, the balloon guide catheter may be inserted through an entry incision into an entry blood vessel, such as the inferior vena cava or femoral artery near the groin. The inner member and outer member are then advanced through the vascular system to position the balloon at a treatment site. The inner member and outer member may be advanced simultaneously, or separately, and at the same rate or different rates.

With the balloon positioned at the treatment site, the balloon is inflated. With the inner member positioned in the sealing position (i.e., the seal positioned within the outer member outlet such that the seal contacts the inner surface of the outer member to seal the annular fluid path), the balloon is inflated by introducing fluid into the outer member lumen such that the fluid flows through the annular fluid path, through the one or more passages, and into the inflatable balloon interior. The remainder of procedure for using the second embodiment is the same as that described above for the first embodiment.

In additional aspects, the method of using the second embodiment of the balloon guide catheter may include the steps of moving the inner member from the non-sealing position to the sealing position, and/or from the sealing position to the non-sealing position.

In yet another aspect of the method, the inner member may be moved relative to the outer member such that the distal portion of the inner member extends beyond a distal end of the outer member to provide a flexible guide portion. This provides a more flexible tip to the balloon guide catheter for guiding and advancing the catheter through the vascular system. The inner member may be advanced to extend the distal portion of the inner member beyond the distal end of the outer member before or during the steps of inserting the inner member and outer member into the vascular system and advancing the inner member and outer member through the vascular system.

In additional aspects, the balloon guide catheter described herein may be used for additional applications beyond a guide catheter. The balloon catheter described herein may be used in any suitable application for a balloon catheter, including performing diagnostic or therapeutic procedures, with or without guiding another catheter using the balloon catheter.

In addition, the balloon catheter described herein may also be configured as a microcatheter for use in any suitable balloon microcatheter application. For instance, the balloon microcatheter has all of the structure and features of the balloon guide catheter described herein, wherein its components, such as the outer member, inner member and balloon, are sized and configured for advancement into small vessels of the vascular system. For example, the balloon microcatheter may be made of components which are more flexible and smaller than a typical balloon guide catheter, such as having an outside diameter (outer diameter of the outer member) of from 0.095 inches and 0.125 inches and an inside diameter (inner diameter of the inner member) of from 0.060 inches to 0.095 inches. For instance, a balloon guide catheter of this size may be useful in performing a thrombectomy aspiration. Moreover, for use within very small vessels, such as the smaller vessels within the neurovascular, the outer diameter of the outer member is from 0.027 inches to 0.037 inches and the inner diameter of the inner member is from 0.016 inches and 0.026 inches. Accordingly, the balloon microcatheter may be advanced into very small vessels of the vascular system, such as within the neurovascular, cardiovascular, or other small vessels.

Accordingly, embodiments described herein provide an innovative balloon guide catheter and methods of using the same which allow for faster preparation and more effective purging of air within the catheter than prior balloon catheters.

