1. Field of the Invention
This invention relates to heart-assist devices and, more particularly, to such devices incorporating balloon pumps.
2. Prior Art
During the past thirty years there has been an ever-increasing frequency of heart surgery and greater study and knowledge of the functions of the heart. One of the product groups which has resulted from this increased activity in the knowledge of the function of the heart has been what are known as temporary circulatory-assist devices. The purpose of such devices is to stabilize, hemodynamically, a failing circulatory system resulting from a failure in the pumping action of the heart. Beneficial results have been realized by the use of heart-assist devices in patients with cardiogenic shock and in severe acute myocardial ischemia. Further, in the critical moments before or after a heart transplantation or after open heart surgical procedures, temporary support of the cardiocirculatory system is crucial.
These heart-assist devices are intended to give the heart muscle the necessary time to rest and optionally to recover.
The best known of the circulatory-assist devices is the intra-aortic balloon with its counterpulsation capability. With the development of percutaneous techniques for the balloon insertion (for example, through the femoral artery) it is possible to give immediate response to a critical heart condition. However, with the intra-aortic balloon, the cardiac output is increased approximately thirty to forty percent. It is clear that a more effective heart-assist device is necessary, particularly in the first moments of intervention, to prevent deterioration of the circulatory system of the patient.
Therefore, it is an object of this invention to provide a heart-assist device which is compact, is easily handled by a single specialist, is completely a traumatic both to the ventricular chamber and to the blood volume constituents, and is highly effective so as to achieve nearly normal physiological conditions during its use.