Abstract: A system for removing gas bubbles from blood during circulatory assist procedures. An active filter apparatus forces the bubbles to the center of the system where they are removed from the blood before the blood exits the filter.

Abstract: Methods for rotating a heart valve body rotatably mounted within a sewing ring. The valve body includes a plurality of drive surfaces on an inner periphery, and a rotator has a plurality of drive surfaces on an exterior periphery. The drive and driven surfaces are in registration only in discrete relative orientations of the two parts about a common axis of rotation. The drive surfaces may be greater in number than the driven surfaces, to reduce the rotational angle that the rotator must be turned before registering with the valve body. The drive and driven surfaces may be formed as flats on each respective part. In one embodiment, the rotator includes a cylindrical distal end with three pairs of diametrically opposed external flats, and the valve body includes a single pair of diametrically opposed internal flats. The rotator is designed so that a surgeon need only rotate it a maximum of 90.degree. in either direction.