Abstract: 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.

Abstract: An implantable ventricular assist system uses a small high-speed axial flow blood pump which may be grafted into the patient's circulatory system. The pump includes a blood tube in which the pump rotor and stator are coaxially contained, and a motor stator surrounding the blood duct. A permanent magnet motor rotor is integral with the pump rotor. Purge fluid for the hydrodynamic bearings of the device and power for the motor are preferably percutaneously introduced from extracorporeal sources worn by the patient. The purge fluid is introduced into the pump stator blades. This construction avoids the creation of discontinuities in the blood path wall due to the routing of drive power and/or fluid supply elements through the blood path wall. The described construction greatly reduces the size of the implant needed for a given blood flow rate and enhances its physiological compatibility with the body.

Abstract: A high-frequency transvalvular blood pump for temporary cardiac assist provides suction to decompress the ventricular cavity during both systole and diastole. The intake end of the pump is connected to a cannula which is inserted into the ventricular cavity through the aortic valve, and which has an intake opening at its distal end. The intake and outflow ends of the pump are closed, respectively, by one-way valves which allow blood flow only in the direction of body perfusion. The pump itself consists of a stiff barrel whose interior volume can be alternately reduced and expanded by a flexible membrane controlled by pneumatic or hydraulic pressure from an extracorporeal location through a percutaneously inserted lumen.

Abstract: 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.

Abstract: 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.

Abstract: The outside diameter of an intravascular axial flow blood pump is reduced without reducing the size of its journal bearings by causing the pumped blood stream to exit through apertures in the cylindrical outside wall of the pump housing between the rotor blades and the rotor journal. This allows the journal to have a diameter of the housing, without the need for a space-consuming blood flow path around the journal.

Abstract: An implantable axial flow blood pump maximizes the blood flow while minimizing the dimensions of the pump. By magnetically suspending a rotor of relatively small diameter coaxially in a cylindrical blood conduit of substantially larger inner diameter, an adequate flow area through the pump is provided, and the need for bearings, lubrication and seal purging fluid is eliminated. This is made possible by the use of neodymium-boron-iron rotor magnets which allow a substantial gap between the static motor armature and the rotor. The rotor is simultaneously torqued and maintained in a position coaxial with the blood conduit by individually varying the current in the armature windings while they are being commutated. The position of the rotor axis is accurately sensed by placing magnetically permeable strips into opposite ends of the pump stator blades in such a manner that they transmit to Hall sensors variations in an annular magnetic field surrounding the rotor adjacent the ends of the pump stator blades.