Tc1 LLC

Thoratec Corporation

Masamichi Yanai

Alexander Medvedev

Tao Zhang

Jason C Nanna

Shunzhou Yu

Jeffrey H Campau

Muhammad Sami

J Bradford Rainier

Russel J Corvese

Himanshu K Bhatt

Jeffrey G Houdek

A blood pump system is implantable in a patient for ventricular support. A pumping chamber has an inlet for receiving blood from a ventricle of the patient. An impeller is received in the pumping chamber. A motor is coupled to the impeller for driving rotation of the impeller. A motor controller is provided for tracking systolic and diastolic phases of a cardiac cycle of the patient and supplying a variable voltage signal to the motor in a variable speed mode to produce a variable impeller speed linked to the cardiac cycle. The impeller speed comprises a ramping up to an elevated speed during the diastolic phase in order to reduce a load on the ventricle at the beginning of the systolic phase.

Cardiac pump with speed adapted for ventricle unloading

A blood pump system includes a pump housing and an impeller for rotating in a pump chamber within the housing. The impeller has a first side and a second side opposite the first side. The system includes a stator having drive coils for applying a torque to the impeller and at least one bearing mechanism for suspending the impeller within the pump chamber. The system includes a position control mechanism for moving the impeller in an axial direction within the pump chamber to adjust a size of a first gap and a size of a second gap, thereby controlling a washout rate at each of the first gap and the second gap. The first gap is defined by a distance between the first side and the housing and the second gap is defined by a distance between the second side and the pump housing.

Alternating pump gaps

A centrifugal blood pump includes a housing that defines an inlet passage, a chamber, and an outlet passage. The pump includes an impeller rotatably positioned in the chamber to transfer blood from the inlet passage through the chamber and to the outlet passage and magnetic members embedded in the impeller such that the impeller and the magnetic members rotate together within the chamber. The pump includes a motor to control movement of the impeller in the chamber. The motor is adjacent the chamber and separated from the chamber by a partition member. The pump includes an inner annular magnetic member and an outer annular magnetic member embedded in a side of the housing opposite the partition member. A first net magnetic force between the inner annular magnetic member and the magnetic members exhibits greater attraction than a second net magnetic force between the outer annular member and the magnetic members.

Impeller suspension mechanism for heart pump

A centrifugal pump system having an impeller rotating with first and second magnetic structures on opposite surfaces. A levitation magnetic structure is disposed at a first end of a pump housing having a levitating magnetic field for axially attracting the first magnetic structure. A multiphase magnetic stator at a second end of the pump housing generates a rotating magnetic field for axially and rotationally attracting the second magnetic structure. A commutator circuit provides a plurality of phase voltages to the stator. A sensing circuit determines respective phase currents. A controller calculates successive commanded values for the phase voltages in response to the determined phase currents and a variable commutation angle. The angle is selected to correspond to an axial attractive force of the stator that maintains a levitation of the impeller at a centered position within the pumping chamber.

Impeller position compensation using field oriented control

A centrifugal pump system having an impeller rotating with first and second magnetic structures on opposite surfaces. A levitation magnetic structure is disposed at a first end of a pump housing having a levitating magnetic field for axially attracting the first magnetic structure. A multiphase magnetic stator at a second end of the pump housing generates a rotating magnetic field for axially and rotationally attracting the second magnetic structure. A commutator circuit provides a plurality of phase voltages to the stator. A sensing circuit determines respective phase currents. A controller calculates successive commanded values for the phase voltages during a running state in response to a desired impeller speed and an actual impeller phase. The controller has a startup interval during which the commanded values of the phase voltages are determined in response to a pseudo impeller phase and in response to a ramping gain factor.

Startup sequence for centrifugal pump with levitated impeller

A blood pump system for left ventricle assist has an implantable pump unit having a multiphase stator having a plurality of windings connected between respective junctions for forming first, second, and third phases. An external control unit comprises an H-bridge inverter having first, second, and third phase legs. A percutaneous cable is provided having first, second, and third parallel pairs of redundant conductors. Each conductor pair is connected between a respective phase leg and a respective junction. The conductors are arranged concentrically around a cable core so that individual conductors of each pair are separated by at least one conductor of a different conductor pair.

Percutaneous cable with redundant conductors for implantable blood pump

The magnetic balance is verified of a magnetically-levitated impeller of a centrifugal pump with a pump housing having levitation magnets. The impeller includes embedded magnets and is movable within a chamber in the pump housing between first and second sides of the chamber. The centrifugal pump is mounted on an acceleration fixture while the impeller is held against a predetermined one of the first and second sides by the levitation magnets. A plurality of predetermined accelerations are applied to the acceleration fixture to exert a plurality of different forces of acceleration on the impeller. A determination is made whether the impeller detaches from the predetermined side as a result of each different force of acceleration to identify adjacent forces for which a transition occurs between detaching and not detaching. The transition is compared with a desired retention force to determine whether the pump achieves magnetic balance.

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Ann Arbor, MI, United States of America

Masamichi Yanai