BALLOON CATHETER WITH SAFETY FEATURE

FIELD OF THE INVENTION

[0001] This invention relates to a balloon catheter generally and, in particular, to a safety feature that is associated with a balloon catheter for preventing harm to a patient in the event the balloon ruptures during a percutaneous medical procedure.

BACKGROUND OF THE INVENTION

[0002] Balloon catheters have been known and used in the art for a number of years. Advances in the art have considerably reduced the risk of the balloon becoming dislodged from the catheter during a medical procedure. Another risk associated with balloon catheters is the danger of the balloon rupturing inside a patient while inflated. Although the risk of rupture is extremely small, it can be dangerous if the rupture occurs within a vital organ, such as the heart or the like. Pressures of between 60 and 100 psi are often used to inflated catheter balloons and, in the case of a rupture, the escaping inflation fluid as well as any dislodged pieces of balloon membrane can impact sensitive body tissue it comes in contact with. Any residual pieces of membrane that are not recovered can also pose a further danger to the patient.

[0003] In the event of a balloon failure taking place during a medical procedure, the catheter generally has to be removed from the patient and a new catheter percutaneously passed into the procedure site. Removal of a catheter with a ruptured balloon attached can sometime prove difficult and potentially dangerous because fragments of the ruptured balloon can be stripped away from the catheter as it is being withdrawn.

SUMMARY OF THE INVENTION

[0004] It is a primary object of the present invention to improve balloon catheters.

[0005] It is a further object of the present invention to protect a patient from harm in the event a balloon that is attached to the distal end of a catheter ruptures during a medical procedure.

[0006] A still further object of the present invention is to safely contain the inflation fluid as well as balloon fragments of a balloon catheter in the event the balloon fails during a medical procedure.

[0007] Yet another object of the present invention is to prevent the interruption of an in-process medical procedure in the event an inflated balloon of a balloon catheter ruptures during a medical procedure.

[0008] These and other objects of the present invention are attained by means of a balloon catheter that has an outer balloon affixed to the distal end of the catheter insertion tube. A second inner balloon is similarly affixed to the insertion tube and is entirely enclosed within the outer balloon. A vacuum pump is connected to the outer balloon through the insertion tube and is arranged to evacuate the atmosphere of the outer balloon. A pump is connected to the inner balloon which is arranged to inflate the inner balloon to a desired pressure. In the event, the inner balloon is ruptured during inflation, the high pressure inflation fluid is released into the outer balloon and is thus contained therein along with any of the inner balloon fragments that might be dislodged because of the rupture. Finally, in certain cases, the medical procedure can proceed without interruption after a rupture by simply inflating the outer balloon to a desired operational level.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] For a better understanding of these and other objects of the present invention, reference will be made to the following detailed description of the invention that should be read in association with the accompanying drawings, wherein:

[00010] Fig. 1 is a side elevation illustrating a balloon catheter embodying the teachings of the present invention;

[00011] Fig. 2 is an enlarged sectional view taken along lines 2-2 in Fig. 1 showing the inner and outer balloons in a semi-inflated state; and

[00012] Fig. 3 is an enlarged sectional view taken along lines 3-3 in Fig. 1 showing the inner balloon fully inflated within the outer balloon.

DETAILED DESCRIPTION

[00013] A balloon catheter, generally referenced 10, that embodies the present invention, is illustrated in Fig. 1. The catheter includes a hollow insertion tube 12 that is fabricated of a plastic material having sufficient flexibility such that it can be percutaneously inserted into a desired body cavity via a blood vessel. A balloon assembly, generally referenced 15, is affixed to the distal end 17 of the insertion tube 12. The assembly consists of a first cylindrical outer balloon 20 that surrounds the insertion tube and a second cylindrical inner balloon 21 that also surrounds the insertion tube 12 and is completely contained within the outer balloon. Each of the balloons 20, 21 is made of a thin wall membrane that is capable of expanding when inflated with a suitable fluid which can be a gas, vapor or fluid. In most cases, air is used to inflate most balloons use din the art. The axial length of the outer balloon 20 is slightly longer than that of the inner balloon 21 and of the assembly between the balloons. The balloons 20, 21 can be fabricated of any one of many well known copolymers that are used in the art. Preferably, both balloons are made from the same material.

[00014] The thin walls of the two superimposed balloons 20, 21, when deflated, provides an extremely compact package upon the distal insertion tube 12 which can pass with relative ease through a blood vessel into a desired treatment zone. The size of the dual balloon package is about the same size as that of a single balloon package and thus does not present any additional problem during insertion and removal of the catheter 10. The opposite ends of the outer balloon 20 each contain a cuff 30 (Fig. 2) that surrounds the insertion tube 12 and are affixed thereto to establish an air tight joint between the two cuffs and the tube. Similarly, the two ends of the inner balloon 21 each contain a cuff 33 that is affixed to the insertion tube to provide an air tight joint therebetween.

[00015] With further reference to Fig. 2, the outer balloon 20 is connected to a syringe 35 capable of evacuating the balloon via a lumen 37. One end of the lumen 37 is coupled to the syringe 35 and passes through the insertion tube 12 to a point beneath the balloon package. The terminal end 38 of the lumen 37 is passed through the insertion tube 12 into the space 18 between the two balloons 20, 21 and the connection rendered air tight by any suitable manes. A shut off valve 40 is mounted in the proximal end of the lumen 37 which when placed in an open position permits the syringe 35 to evacuate the outer balloon 20. Placing the valve 40 in a closed position, in turn, holds the vacuum within the balloon 20 and thus maintains the balloon in an evacuated condition.

[00016] The inner balloon 21 is similarly connected to a syringe 50 by means of a second lumen 51. Again, the syringe 50 is coupled to the proximal end of the lumen 51 and the lumen is passed through the insertion tube 12 to a point below the inner balloon 21. The distal end of the lumen 51 is passed through the insertion tube 12 into the inner balloon 21 and the connection between the lumen and the insertion tube is closed to form an air tight joint therebetween. A second stop valve 56 is mounted in the proximal end of lumen 51. When the valve 56 is placed in an open position, the syringe 50 is able to deliver sufficient air into the inner balloon 21 to completely inflate the balloon. Closing the valve 56 will prevent air from escaping from the balloon 21 and thus maintain the balloon in an inflated condition.

[00017] In operation, before passing the catheter 10 into a blood vessel, the stop valve 56 that controls inflation of the inner balloon 21 is opened as well as the stop valve 40 that controls the evacuation of the outer balloon 20, thus allowing the balloons to be wrapped about the insertion tube 12 into a tight package and the outer balloon is evacuated and valve 40 is closed. Once the balloon package is properly positioned in the treatment site, the inner balloon 21 is inflated. The outer balloon 20 at this time provides little resistance to the expanding inner balloon 21 and simply rides upwardly on the outer balloon until it reaches full inflation whereupon stop valve 56 is closed. If for any reason the inner balloon 21 should fail while fully or partially inflated, the air contained within the inner balloon will be discharged into the slightly larger outer balloon 20 and be fully contained therein. Any fragments of the inner balloon 21 that might breakaway will also be captures within the outer balloon 20 and eventually be safely removed from the patient when the catheter is removed.

[00018] The addition of the second balloon to the catheter consumes little additional space and sufficient room is made available within the insertion tube for a third lumen 61 through which a guide wire can pass.

[00019] In many cases, failure of a balloon while a medical procedure is in process results in the procedure being terminated and the catheter being removed from the patient and a new procedure having to be initiated. This is not only time consuming but also potentially dangerous and uncomfortable for the patient. The problems associated with a balloon failure during a medical procedure can be avoided by use of this dual balloon arrangement. If such a failure does occur during a procedure, the air escaping from the ruptured inner balloon 21 will partially fill or almost completely fill the outer balloon 20. If necessary, the syringe servicing the outer balloon 20 can be used to fully inflate the outer balloon through proper operation of the associated stop valve and the procedure carried on to completion.

[00020] While the invention has been described with reference to preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof to adapt to particular situations without departing from the scope of the invention. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope and spirit of the appended claims.