A blood pump for closed-chest left ventricular bypass

In the quest for more effective and less traumatic methods of treating heart failure the Baylor University College of Medicine, Department of Physiology, has developed a new method of left ventricular assistance. The method does not require thoracotomy and provides assistance to the failing myocardium. Inherent in this method, however, are some rather severe limitations on the pump and pumping system used in implementing the assist. Most notable among these is a long, small diameter tube (catheter) which is placed in the failing ventricle via a carotid artery in the neck. The catheter is used to withdraw blood from the ventricle for later infusion into the arterial tree. The dimensions of the catheter produce a significant pressure drop which is seen as a vacuum at the pump inlet. This vacuum, with normal pumps, decreases flow rates, increases hemolysis rates and results in other undesirable features of pump performance.