Method of implanting blood pump in ascending aorta or main pulmonary

Abstract

This invention relates to a method of surgically implanting a blood pump into the ascending aorta or pulmonary artery of a patient with a diseased or damaged heart ventricle. One preferred type of pump which is well-suited for such implantation has an impeller design that generates central axial flow (CAF). After implantation of the CAF pump, blood flows through the hollowed-out rotor shaft of an electric motor. The CAF rotor shaft contains angled vanes mounted on the inner surface of the hollow shaft, extending only part of the distance toward an imaginary axis at the center of the rotor shaft. Rotation of the hollow shaft with its angled vanes pumps blood through the pumping unit. The vanes contact and impart forward motion to a portion of the blood at the periphery of the flow path, generating an outer fluid annulus which is being directly propelled by the vanes. Blood cells near the center of the cylinder are not touched by the vanes as they pass through the pump; instead, they are drawn forward by viscous flow of the surrounding annulus. In the method of this invention, the pump and motor unit is inserted downstream of an aortic or pulmonary valve which is left intact and functioning, by means such as suturing the arterial walls to short attachment cuffs at each end of the pump. After insertion, the pump lies directly in line with the artery, so that directional changes, shear forces, and artificial surfaces contacted by blood are all minimized. Unlike shunt systems, placement entirely within an aorta or pulmonary artery can provide pulsatile flow if desired, and can reduce the pressure that a damaged or diseased ventricle must pump against. In addition, the placement and design of the CAF pump allow maximal use of the residual functioning of the patient's heart and will not lead to catastrophic backflow if the pump suffers a power or mechanical failure.