Surgery – Miscellaneous – Methods
Reexamination Certificate
2000-03-13
2001-02-13
Getzow, Scott M. (Department: 3762)
Surgery
Miscellaneous
Methods
Reexamination Certificate
active
06186149
ABSTRACT:
FIELD OF THE INVENTION
The present invention is related in general to medical devices. More specifically, the present invention is related to an occluder device and related systems and methods.
BACKGROUND OF THE INVENTION
It is known that in the event of blood pump motor failure, potentially fatal retrograde blood flow can occur between the descending aorta and the left atrium, resulting in immediate heart failure. The present invention can be used to prevent reverse flow through automatic occlusion of the pump outlet flow tube during and/or following pump failure.
Furthermore, the occluder device can function as an anti-kink sheath for the junction of the rigid outlet port of the blood pump housing and the flexible outlet flow tube. The anti-kink sheath eases the transition through its semi-flexible characteristics.
Prior art of vascular occluder includes U.S. Pat. No. 5,057,118, which describes a vessel occlusion device. The device has an adjustable metal clip consisting of a foam base. It supposedly results in little trauma to vessels. One problem is that it cannot be activated remotely.
U.S. Pat. No. 5,074,869 discloses a vascular occlusion device. This device comprises a pressure tube molded to a slender bladder. The bladder is wrapped around the vessel and secured with a suture. It is designed to work on small vessels in areas that are not easily accessible. There is no mention of artificial graft applications in ventricular assist devices or automatic applications.
U.S. Pat. No. 5,152,770 describes an implantable device for occluding a duct in the body of a living being. This device operates similarly to the previous system. It is wrapped and secured around a vessel and inflated. Again, no mention of artificial graft applications or automation is made.
U.S. Pat. No. 3,538,917 describes a balloon occlusion clip. This device comprises a rigid outer C-shell with a bladder molded to the inside of the shell. The device is put in place by spreading the C-shell and placing over the vessel.
None of the aforementioned patents are concerned with circulatory assist devices or the prevention of retrograde flow therethrough.
SUMMARY OF THE INVENTION
The present invention is a circulatory system, such as a circulatory assist system for a patient. The system comprises a blood pump having tubing fluidically communicating with a person's blood vessel. The blood pump can be, for instance, a centrifugal blood pump but is not limited thereto. The system also comprises an occluder device for controlling flow of the blood pump. The occluder device is in contact with the tubing of the blood pump. The occluder device can be incorporated into an anti-kink sheath over the outlet graft tubing of the blood pump. Preferably, the system comprises control means for actuating the occluder device when the blood pump malfunctions. In this manner, potentially fatal retrograde blood flow due to pump failure is automatically prevented.
In a preferred embodiment, the occluder device comprises a cylindrical tube and a bladder mechanism connected to the inside surface of the tube. The bladder mechanism preferably comprises a bladder and means for inflating the bladder. The inflating means communication with the bladder. Preferably, the bladder mechanism also comprises a pressure sensing means such as a hysteresis pressure switch. Preferably, the control means also comprises means for sensing blood pump failure.
The occluder device can be connected with the tubing of the blood pump either externally, or in-line. With the external construction, the tubing of the blood pump passes through the occluder tube. The tubing is unbroken and thus the blood never contacts the occluder device. The in-line construction comprises a connection between each end of the pump outlet tubing and the occluder tube. In this manner, blood flows through the occluder tube and contacts the bladder. Thus, with the in-line construction, it is absolutely critical that the blood contacting surface of the tube/bladder and the occluder tube/outlet tube interfaces be continuous to avoid surface anomalies and subsequent thrombus formation. That is, the presence of significant varying surface profiles, air bubbles, holes, or any other slight discontinuities at these areas can result in irregular blood flow patterns and eventual thrombosis. Another in-line arrangement could involve molding the bladders directly onto the inner wall of the pre-existing inlet tube of the blood pump. This method would eliminate the need to create interfaces between the occluder tube and the outlet tube. The inlet tube of the blood pump would serve as the occluder tube.
The bladder can be of a variety of constructions in the occluder tube. The bladder can cover all or a portion of the inner surface of the tube. Also, two bladders can oppose each other, in a non-overlapping manner within the tube. Alternatively, the bladder can cover the entire 360° of the inner surface and function as a ring bladder. In this manner, as the bladder is inflated, the orifice closes with decreasing diameter, much like a natural biological valve.
The occluder device could be rapidly inflated and deflated for applications as a valve in an internal configuration, with the bladders in direct contact with the blood stream. The device could be used in the same fashion externally, with the bladders directly opposing the outer wall of the outlet flow tube. In either case, the normal steady flow output of a blood pump (when heart completely dysfunctional) would be transformed to a pulsatile output.
The present invention also pertains to an occluder device exclusively. The occluder device comprises a tube having a closed annular cross section and an inflatable bladder mechanism connected to the inner surface of the tube. The unique closed annular shape of the tube provides a permanent frame and can be used as a flow channel, or as another example, as an anti-kink sheath for flexible tubing.
The present invention also pertains to a method of forming an occluder. The method comprises the step of disposing a mask material, such as gelatin, on an inner surface of a tube. Next, there is the step of applying a bladder material to the inner surface over the mask material. Then, there is the step of providing a hole through the tube under the mask material for inflating the bladder material. Preferably, after the providing step, there is the step of removing the mask material through the hole.
REFERENCES:
patent: 5479946 (1996-01-01), Trumble
patent: 5826584 (1998-10-01), Schmitt
Clark Richard E.
Pacella John J.
Allegheny-Singer Research Institute
Getzow Scott M.
Schwartz Ansel M.
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