WO1990003823A1

WO1990003823A1 - Inflation device for ballon catheter

Info

Publication number: WO1990003823A1
Application number: PCT/US1989/004483
Authority: WO
Inventors: Louis O. Noce
Original assignee: Mallinckrodt, Inc.
Priority date: 1988-10-12
Filing date: 1989-10-10
Publication date: 1990-04-19
Also published as: AU4343789A; CA2000470A1; US4940459A; JPH04502713A

Abstract

An inflation device for a balloon catheter has a pistol grip handle (22) with a trigger (30) for releasing a screw plunger (24) to enable rapid inflation and deflation of the balloon catheter. The trigger bias and thread angle of mating threads are selected to automatically release the plunger when a safe balloon catheter pressure is exceeded. A trigger guard (36) is slidable over the trigger to prevent accidental operation and pressure release.

Description

INFLATION DEVICE FOR BALLOON CATHETER

BACKGROUND OF THE INVENTION Technical Field

The present invention relates to inflation devices for inflating inflatable balloon catheters, used in interventional medical procedures like percutaneous transluminal angioplasty (PTA) and percutaneous transluminal valvuloplasty (PTV). Description of the Prior Art Prior to the development of angioplasty or PTA, patients with occluded coronary arteries were primarily treated by arterial or saphenous vein graft bypass operations. These bypass operations involve the suturing of the opposite ends of a blood vessel segment to the opposite sides of the blocked section of the coronary artery. The blood vessel segment may be either a vein segment removed from the patient's leg or an artery segment, for example. Bypass operations are costly, require a long patient convalescence, and involve considerable risk which may result in death for many older patients or patients in poor heath.

Angioplasty is now used in place of a bypass operation in many patients, and especially on patients for whom bypass operations are too risky. During angioplasty, a catheter with a deflated balloon is inserted through arteries to place the deflated balloon in the occluded area. The balloon is then inflated with a solution of sterile contrast media and other sterile fluid and maintained at several atmospheres of pressure for a brief time period to enlarge the artery and allow blood flow to return to an acceptable level after the balloon is deflated. Balloon repositioning, inflation, and deflation may be repeated several times to achieve the desired results. The PTA procedure has many advantages over bypass operations because the PTA procedure does not require invasive surgery, is much less traumatic on the patient, and requires a far shorter recovery period.

Similarly, valvuloplasty or PVA has recently been developed as an alternative to major surgical operations, such as valve replacement or valvotomy. Valve replacement involves removal of the damaged heart valve and replacement with a porcine valve or an artificial valve. Valvotomy includes surgical cutting of the heart valve to remove or open damaged or stenotic areas.

In valvuloplasty,-the balloon on a balloon catheter is expanded in the defective valve in order to enlarge the valve opening. This restores sufficient valve function to return the blood flow through the valve to an acceptable level. As in angioplasty, the procedure is non-invasive and the patient's recovery period is much less than that required following surgical methods.

It is preferable for an inflation device used with a balloon catheter in angioplasty or valvuloplasty to precisely inflate the balloon to a desired pressure; maintain that pressure; and then deflate the balloon to the point of achieving a vacuum, to allow catheter removal o repositioning. Balloon catheters from different manufacturers and for different procedures require varying pressures. In an emergency situation the inflation device must be capable of rapidly inflating and deflating the balloon catheter.

There are several inflation devices commercially available in the prior art. Generally, these inflation devices include a pressure gauge to display the precise fluid pressure transmitted to the balloon, and employ screw plungers to enable the physician to precisely set the pressure. The prior art devices may also include quick release levers for disengaging; driving thread sector members from the screw plunger threads to allow rapid plunger movement during inflation or deflation. The prior art inflation devices have several deficiencies, including, having handles which have a shape and location which make it difficult to simultaneously hold and operate the inflation device; having little or no safety features; and having hidden fluid pressure chamber regions or passageways which allow undetected air bubbles to be trapped where they interfere with pressurization or pose a threat in the event of balloon failure.

SUMMARY OF THE INVENTION The present invention relates to an inflation device for a balloon catheter wherein the device includes a pistol grip handle having a trigger. The trigger operates a quick release means for a threaded member which is biased into engagement with a screw plunger which is slidable in a barrel of the device for providing pressurized fluid to the catheter. The operator may grip the handle of the inflation device by one hand, and can operate the quick release trigger using a finger on the gripping hand. The other hand of the operator can slide the plunger for a quick pressure change when the trigger is depressed or can rotate the plunger for a precise pressure change when the threaded member is engaged with the screw plunger.

The present invention also relates to an inflation device for a balloon catheter wherein the device includes a pivoted thread sector member biased against a screw plunger in a barrel of the device. The thread sector member holds the plunger and enables the plunger to be screwed in the barrel to precisely set fluid pressure in the catheter. The biasing force is selected to provide automatic release of the plunger when the pressure in the barrel exceeds a predetermined safe pressure for the catheter. This biasing force is selected in conjunction with the engaging thread parameters, which include a screw thread angle between 20° and 160°.

The present invention further relates to an inflation device for a balloon catheter wherein the device includes a guard means mounted for movement over a quick release trigger. When employed, the guard means prevents operation of the trigger which would release a plunger in a barrel of the device and allow rapid increase or decrease of the pressure in the balloon of the catheter. Accidental operation of the trigger is prevented by the guard means so that a desired pressure may be maintained in the balloon. For example, a negative pressure with respect to atmospheric pressure can be maintained in the balloon during advancement of the catheter through arteries.

An object of the present invention is to construct an inflation device for a balloon catheter which provides for easier and more rapid operation.

Another object of the present invention is to provide an inflation device for a balloon catheter which includes automatic safety features.

Still another object of the present invention is to provide an inflation device which can be manipulated without risk of release pressure being maintained by the device.

One advantage of the present invention is that angioplasty and valvuloplasty procedures are improved because the physician is able to more rapidly and precisely bring about balloon treatment pressures. Another advantage of the present invention is that patient safety is improved by an automatic pressure release for preventing accidental pressure increases which could otherwise cause blood vessel damage or balloon failure.

Still another advantage of the present invention is that operation of a quick release trigger in an inflation device is prevented by a trigger guard during manipulation of a catheter or the device.

Additional features may be included in the invention such as an insert molded plunger which provides plunger strength along with corrosion resistance and pressure fluid compatibility. Further, a clear molded pressure barrel may be provided and mounted to allow visibility of the pressurizing fluid and enable purging and removal of all air bubbles. Also, clear high pressure tubing may be used which enables visualization and purging of air bubbles.

Moreover, a pressure gauge may be included, which directly measures fluid pressure through a range including vacuum to pressures above the upper pressure limits of the catheter.

Other objects, advantages, and features of the invention will be apparent from the following description of the preferred embodiment and accompanying drawings.

BRIEF DESCRIPTION OF THE INVENTION

Fig. 1 is a side elevational view of a device for inflating a balloon catheter in accordance with the invention.

Fig. 2 is a side sectional view, with portions removed, of the device shown in Fig. 1.

Fig. 3 is a sectional view taken along line 3-3 of Fig. 2 showing a thread section broken away from a trigger in the inflation device.

Fig. 4 is a sectional view taken at an axial plane of a broken away portion showing a threaded shank of a plunger in the device of Fig. 2.

Fig. 5 is a cross sectional view taken along line 5- 5 of Fig. 2 showi g a handle of the inflation device.

Fig. 6 is a sectional view taken along line 6-6 of Fig. 5 of broken away portions of a handle and trigger guard of the inflation device.

DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in Figs. 1 and 2, the present invention relates to an inflation device which includes a barrel indicated generally at 20 mounted on a pistol grip handle indicated generally at 22 and a plunger indicated generally at 24 slidably retained in the barrel. The plunger 24 includes a threaded shank 26 which is normally engaged by a thread section 28 of a trigger 30. The trigger is pivotally mounted in the handle with pivot pins 32. A compression spring 34 biases the trigger 30 to urge the thread section 28 into engagement with the threaded shank 26. A trigger guard 36 is slidably mounted on the handle 22 for sliding over the trigger 30 to prevent accidental operation of the trigger.

In use, the barrel 20 is filled with fluid and the open end 40 of the barrel 20 is connected by tubing 42 and connector 44 to a balloon catheter (not shown) . The operator grasps the handle 22 in one hand with the trigger 30 underneath one finger. With the other hand, the operator grasps the knob 46 of the plunger 24 to operate the catheter inflation device. With the trigger 30 depressed by one finger on the hand holding the handle, the plunger 24 the knob 46 is easily pulled to retract the plunger 24 and quickly deflate the balloon of the catheter, or pushed to advance the plunger 24 and inflate the balloon of the catheter. With the trigger 30 released, the knob 46 is easily turned to screw the threaded shank 26 forward or backward on the thread section 28 to precisely set the required fluid pressure for the therapeutic action being performed by the catheter.

If the fluid pressure is increased above a predete mined safe pressure, camming forces generated by the threads of the threaded shank 26 against the thread section 28 overcome the bias of the spring 34 to automatically pivot the trigger 30 and release the plunger 24. The plunger then moves rearward until the pressure is reduced to a level at which the camming forces of the threads of the threaded shank 26 on the thread section 28 no longer exceed the bias of the spring 34.

The barrel 20 is formed by molding from a clear resin, such as clear polycarbonate, and has a main barrel section 50 in which the plunger 24 operates. A scale 52 is formed on the outside surface of the main barrel section 50 so that the amount of fluid passing into and out of the barrel 20 can be determined. A reduced diameter barrel section 54 is formed at the forward end of the main barrel section 50. The open end 40, in which the tube 42 is secured, is formed in the forward end of the reduced diameter barrel section 54. A port 56 is formed in the side of the reduced diameter barrel section 54 and has a pressure gauge 58 secured thereto. The rear portion 60 of the barrel 20 is enlarged and has an opening 62 at the bottom for permitting the thread section 28 of the trigger 30 to extend upward into the rear portion 60 of the barrel 20. A cap 64 is secured over the rear end of the barrel 20 and has a center opening 66 through which the threaded shaft 26 freely extends. The cap 64 forms a guide for the threaded shaft 26 to limit the shaft to movement in axial and rotative directions as well as to retain the plunger 24 in the barrel.

The plunger 24, as shown in Fig. 4, is insert molded, i.e. is formed by molding a polymer such as nylon 6-6, acetyl polymers or high density olefins on a center shaft 68 formed from steel or other metal. The molded polymer forms the outer configuration, including the threads 70 and outer layer 72, which completely encapsulate the metal shaft 68 to prevent rust or corrosion. Forward enlarged piston portion 74 has grooves 76 with O-rings 78 positioned therein, forming a double seal with the interior surface of the main barrel section 50 to prevent leakage of fluid to the rear of the piston portion 74. The knob 46 is suitably secured on the rear end of the shaft 26 after the shaft 26 is assembled in the cap 64.

The pistol grip handle 22, as showing in Fig. 5, is formed from two molded halves 80 and 82 which are suitably secured together. The halves are molded from any suitable polymer such as ABS and have reinforcing ribs 84. A spring guide 86 is formed in one of the halves to provide a recess for receiving the spring 34. The guide 86 also slidingly retains spring cover member 88 which covers the top end of the spring 34. The trigger 30, molded from a suitable polymer such as polycarbonate, has a generally inverted L configuration with an arm 90 extending generally parallel to the barrel 20 and plunger 24 from the pivot pins 32. The spring cover member 88 engages the lower side of the arm 90 while the thread section 28 extends upward from the upper surface of the arm 90. A leg 92 extends downward from the forward end of the arm 90 and has its forward portion exposed through opening 94 in the forward side of the handle 22. The leg 92 may be depressed to pivot the trigger against the bias of the spring 34. The rear portion 60 of the barrel 20 is secured on the upper end of the handle 22. As shown in Figure 1, the handle covers only a lower portion of the rear portion 60 of the barrel 20 so that substantially all of the main section 50 is exposed to allow the operator to view all the fluid contents of the barrel 20. This together with the tubing 42 being clear enables visualization and purging of all air bubbles in the inflation device.

As illustrated in Fig. 3, the thread section 28 is a half annulus with thread segments 96 formed over a predetermined angular portion of the inside surface thereof. These thread segments 96 as well as the threads 70 on the shaft 26 have a selected thread angle (e.g. 98 in Fig. 4) formed from the adjoining thread faces in an axial plane. The angle 98 is generally in a range from 20° to 160° and is preferably in a range from about 40° to 100°. Especially preferred is the standard thread angle of. 60°. The thread angle 98, along with the spring force of the spring 34, frictional forces, the positions of the thread section 28, and engagement of the spring 34 against the arm 90, determine the automatic release pressure of the inflation device. These design factors are generally empirically adjusted until the inflation device achieves automatic release at the predetermined maximum safe balloon catheter pressure. The automatic release pressure is usually in the range of 4 to 25 bar, preferably in the range of 8 to 22, and more preferably about 18 bar for a suitable inflation device.

The trigger guard 36, as shown in Figs. 5 and 6, has two leg portions connected by a middle portion, comprising a C-shaped cross-sectional configuration. Ribs 102 are formed longitudinally along the inner surfaces of the leg portions of the guard 36 and slidingly extend in mating grooves 104 formed in the outer surfaces of the handle halves 80 and 82. The ribs 102 have an upper recess 106 and a lower recess 108 for engaging a projection 110 in each of the grooves 104 to lockingly retain the guard 36 in lower and upper positions. The upper position is shown in dashed lines in Fig. 1. The guard 36 is placed in the upper position, when it is desired to avoid accidental operation of the trigger 30. For example, when a balloon catheter (not shown) is being advanced through arteries, it is desirable to maintain the balloon in a deflated state by a vacuum or negative pressure; i.e. a pressure below atmospheric pressure, in the inflation device. Release of the negative pressure, such as by accidental operation of the trigger 30 during the advancement, could result in expansion of the balloon which would interfere with continued advancement and can be avoided by placing the guard 36 in the upper position. The pressure gauge has a range of about -1 to 20 bar. The gauge may include dual scales providing readings in both atmospheres and pounds per square inch above atmospheric pressure.

Since many modifications, variations, and changes in detail may be made to the above described embodiment, it is intended that all matter in the foregoing description and shown in the accompanying drawings be interpreted as only illustrative and not as limiting on the scope of the following claims.

Claims

What is claimed is:

1. A device for inflating a balloon catheter, comprising: a tubular barrel for receiving an inflation fluid and having fluid outlet means at one end for connecting the barrel to the catheter, a plunger having a sliding piston in the barrel and a threaded shank extending from the piston out the other end of the barrel, a pistol grip handle mounted on the barrel for being gripped by a hand of an operator, a trigger pivotally mounted in the handle and having a thread section for being pivoted into engagement with the threaded shank of the plunger, means for biasing the trigger to urge the thread section thereof into engagement with the threaded shank, a knob on the plunger shank for enabling an operator to screw the plunger into and out of the barrel to increase and decrease the pressure of the inflation fluid, and said trigger being positioned in the handle so as to be operable by a finger on the hand griping the an le to release engagement of the thread section from the threaded shank to enable free sliding movement of the plunger in the barrel.

2. A device for inflating a balloon catheter as claimed in claim 1, including a trigger guard movably mounted on the handle for being moved into a position covering the trigger to prevent operation of the trigger.

3. A device for inflating a balloon catheter as claimed in claim 2, wherein the trigger guard has two leg portions connected by a middle portion to comprise a C-shaped cross section and is slidable over the trigger.

4. A device for inflating a balloon catheter as claimed in claim 3, wherein the trigger guard has ribs on the interior sides of the leg portions of the guard, and the handle has grooves formed on the exterior surfaces thereof for slidingly receiving the ribs.

5. A device for inflating a balloon catheter as claimed in claim 4, wherein the ribs have recesses, and the grooves have projections for engaging the recesses so as to retain the trigger guard in covering and retracted positions.

6. A device for inflating a balloon catheter as claimed in claim 1, wherein said threaded shank and said thread section having mating threads with an angle of thread selected in conjunction with said biasing means to provide for automatic release of the plunger from the trigger when the pressure in the r el exceeds ;J maximum safe pressure for the catheter<

7. A device for inflating a balloon catheter as claimed in claim 6, wherein said automatic release occurs within a pressure range of 4 to 25 bar.

8. A device for inflating a balloon catheter as claimed in claim 7, wherein said automatic release occurs within a pressure range of 8 to 22 bar.

9. A device for inflating a balloon catheter as claimed in claim 8, wherein said automatic release occurs at a pressure of about 18 bar.

10. A device for inflating a balloon catheter, comprising: a tubular barrel for receiving an inflation fluid and having fluid outlet means at one end for connecting the barrel to the catheter, a plunger having a sliding piston in the barrel and a threaded shank extending from the piston out the other end of the barrel, a handle mounted on the barrel for being gripped by a hand of an operator, a pressure release member pivotally mounted in the handle and having a thread section for being pivoted into engagement with the threaded shank of the plunger, means for biasing the pressure release member to urge the thread section thereof into engagement with the threaded shank, a knob on the plunger shank for enabling an operator to screw the plunger into and out of the barrel to increase and decrease the pressure of the inflation fluid, and said threaded shank and said thread section having mating threads with an angle of thread selected in conjunction with said biasing means to provide for automatic release on the pressure release member when the pressure in the barrel exceeds a maximum safe pressure for the catheter.

11. A device for inflating a balloon catheter as claimed in claim 10, wherein said automatic release occurs in a pressure range of 4 to 25 bar.

12. A device for inflating a balloon catheter as claimed in claim 11, wherein said automatic release occurs in a pressure range of 8 to 22 bar.

13. A device for inflating a balloon catheter as claimed in claim 12, wherein said automatic release occurs at a pressure of about 18 bar.

14. A device for inflating a balloon catheter as claimed in claim 10, including a guard member movably mounted on the handle for being moved into a position covering the pressure release member to prevent operation of the pressure release member.

15. A device for inflating a balloon catheter as claimed in claim 14, wherein the guard member has a C-shaped cross section and is slidable over the pressure release member.

16. A device for inflating a balloon catheter, comprising: a tubular barrel for receiving an inflation fluid and having fluid outlet means at one end for connecting the barrel to the catheter, a plunger having a sliding piston in the barrel and a threaded shank extending from the plunger out the other end of the barrel, a handle mounted on the barrel for being gripped by a hand of an operator, a pressure release member mounted on the handle and having a thread section for being pivoted into engagement with the threaded shank of the plunger, means for biasing the pressure release member to urge the thread section thereof into engagement with the threaded shank, a knob on the plunger shank for enabling an operator to screw the plunger into and out of the barrel to increase and decrease the pressure of the inflation fluid, and a guard member movably mounted on the handle for being moved into a position covering the pressure release member to prevent operation of the pressure release member.

17. A device for inflating a balloon catheter as claimed in claim 16, wherein the guard member has two leg portions connected by a middle portion to comprise a C-shaped cross section and is slidable over the pressure release member.

18. A device for inflating a balloon catheter as claimed in claim 17, wherein the guard member has ribs on the interior sides of the leg portions of the guard member, and the handle has grooves formed on the exterior surfaces thereof for slidingly receiving the ribs.

19. A device for inflating a balloon catheter as claimed in claim 18, wherein the ribs have recesses, and the grooves have projections for engaging the recesses so as to retain the guard in covering and retracted positions.