Nimbus Medical, Inc.

John W Carriker

Richard K Wampler

John C Moise

Kenneth C Butler

Reginald R Baxter

The reliability and compactness of a percutaneously insertable intravascular axial flow blood pump are improved by connecting the pump's rotor and drive cable through a resiliently extendable rotor extension. The rotor extension and drive cable fitting are so designed that the thrust bearing surfaces of the purge seal and cable fitting can be preloaded by strongly pulling the cable fitting against the resiliency of the rotor extension to move one of the bearings away from the other, then relaxing it to a predetermined preload, and finally immobilizing the bearing in the position corresponding to that preload.

Percutaneous axial flow blood pump

A disposable, sterilizable cable drive unit for an intravascular blood pump includes a rotor enclosed in a fluid-tight enclosure which can be slipped into the stator of a drive motor. The unit is connectable to a constant-rate purge fluid supply and to a dual-lumen cable sheath. One lumen provides a sterile purge fluid path; the other carries the drive cable to the blood pump and provides a return path for a flushing fluid in which the cable is immersed. The flushing unit is derived from the purge fluid supply at a constant rate, and the rotor may also be immersed in it if desired. The unit is held in the drive motor by a manually operated detent, and the self-centering action of the rotor aligns it with the stator when the motor is energized. The motor is mounted on a gimbal so as to be alignable with the cable sheath at its point of insertion into the patient's vascular system, in order to prevent stresses on the patient and kinks in the cable sheath.

Drive mechanism for powering intravascular blood pumps

A miniature high-speed intravascular blood pump is formed as a single stage with two rows of rotor blades and a single row of stator blades within a tubular housing. The rotor's first row produces a mixed centrifugal and axial flow, while the rotor's second row produces a purely axial flow. The blades of the second row are shaped so as to produce a uniform blood flow along the trailing edges of the blades. For this purpose, the bases of the outer trailing edges of the second row blades have a negative propulsion angle. The pump has a purge-sealed hydrostatic bearing which is spring-loaded for minimum gap. The pump is driven by a cable encased in a dual-lumen, fluid-filled cable sheath formed of a coextrusion of a soft, blood-compatible outer layer and a stiff, abrasion-resistant inner layer. The cable sheath serves both as a purge fluid supply for the bearing, and as a means for flushing abraded debris away from the pump.

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Gold River, CA, United States of America

John W Carriker