Ventricular assist device and method

Abstract

A ventricular assist device includes a stent for placement within a cardiac artery and arranged for placement, the stent arranged to have an open configuration defining a flow path, a rotor sized to fit within the stent and arranged for percutaneous placement the flow path, the rotor including a surface disposed about a central portion and angled with respect to the flow path and having a first plurality of magnets. A collar is sized for placement about the cardiac artery and includes a stator. A power source is coupled to the stator, and the stator and the rotor are arranged to rotate the rotor about an axis. A timing control module controls a rotational speed of the rotor. Accordingly, the surface of the rotor is arranged to move blood along the flow path in response to rotation of the rotor.

What is claimed is: 
     
         1 . A ventricular assist device for a human heart comprising:
 a stent having a cylindrical stent wall with an inner surface defining a flow path and an outer surface sized for placement within a blood vessel;   a stator disposable within the stent, the stator having a plurality of support struts connected to the stator and disposable against the inner surface of the stent wall to position the stator within the stent;   a rotor including an outer surface facing the inner surface of the stent wall and defined in part by at least one blade angled with respect to the flow path, the rotor rotatably mounted on the stator between the inner surface of the stent and the stator,   one of the rotor and the stator comprising a field magnet and the other of the rotor and the stator comprising windings;   a power source operatively coupled to the windings; and   a controller operatively coupled to the power source to selectively control the power source to vary the rotational speed of the rotor.   
     
     
         2 . The device of  claim 1 , wherein the rotor comprises the field magnet and the stator comprises the windings, the windings operatively coupled to the power source. 
     
     
         3 . The device of  claim 1 , wherein the stator has an upstream end and a downstream end, the plurality of support struts depending from the downstream end and connected to the stent. 
     
     
         4 . The device of  claim 1 , further comprising at least first and second bearings disposed between the stator and the rotor to rotatably mount the rotor on the stator, the first bearing disposed at an upstream end of the rotor and the stator and the second bearing disposed at a downstream end of the rotor and the stator. 
     
     
         5 . The device of  claim 4 , wherein the first bearing is a mechanical pivot and the second bearing is a magnetic bearing and comprises first and second magnets, the first magnets attached to the rotor and the second magnets attached to the stator, the first and second magnets having aligned polarities. 
     
     
         6 . The device of  claim 4 , wherein the first bearing is a hydrodynamic pivot and the second bearing is a magnetic bearing and comprises first and second magnets, the first magnets attached to the rotor and the second magnets attached to the stator, the first and second magnets having aligned polarities. 
     
     
         7 . The device of  claim 4 , wherein the first and second bearings are each a magnetic bearing that comprises first and second magnets, the first magnets attached to the rotor and the second magnets attached to the stator, the first and second magnets having aligned polarities. 
     
     
         8 . The device of  claim 1 , wherein the stator has a elongate body with a mechanical bearing at a first end and a magnetic bearing and the plurality of support struts at a second end, and the rotor has an elongate, hollow body defining an enclosed space in which the elongate body of the stator is disposed with the rotor connected to the stator via the mechanical bearing at the first end of the rotor and the magnetic bearing at the second end of the rotor. 
     
     
         9 . The device of  claim 1 , wherein the at least one blade is collapsible against the outer surface of the rotor, and the ventricular assist device comprising an introducer jacket, the blades collapsed against the rotor with the introducer jacket disposed about the rotor and the blades extended from the outer surface of the rotor without the introducer jacket disposed about the rotor. 
     
     
         10 . The device of  claim 1 , wherein the cylindrical stent wall comprises a metal mesh tube. 
     
     
         11 . The device of  claim 1 , wherein the controller is programmed to operate the power source to provide a pulsatile flow. 
     
     
         12 . The device of  claim 1 , further comprising a cardiac sensor operatively coupled to the controller, the controller being programmed to use the cardiac sensor to determine native cardiac rhythms, and to control the rotational speed of the rotor in response to the native cardiac rhythms. 
     
     
         13 . The device of  claim 1 , wherein the controller is programmed to control the rotational speed of the rotor between a baseline speed and a higher speed. 
     
     
         14 . The device of  claim 1 , wherein one or more of the stent, the stator and the rotor are coated with an anti-coagulant. 
     
     
         15 . The device of  claim 1 , wherein the stent, rotor and stator are sized to fit within one of the aorta and the pulmonary artery. 
     
     
         16 . The device of  claim 15 , wherein the stent, rotor and stator are sized to fit within one of the aorta and the pulmonary artery at a selected location that is supravalvular. 
     
     
         17 . The device of  claim 1 , wherein the power source and the controller are sized for subcutaneous placement. 
     
     
         18 . The device of  claim 17 , wherein the power source is arranged for transcutaneous charging. 
     
     
         19 . The device of  claim 17 , wherein the controller is arranged for transcutaneous programming. 
     
     
         20 . A method of implanting a ventricular assist device in a heart, comprising the steps of:
 selecting a stent sized for placement within a blood vessel at a selected location within the blood vessel;   placing the stent at the selected location in a collapsed configuration;   expanding the stent at the selected location to define a flow path through the stent;   placing a stator within the stent in the flow path,   providing a rotor including an outer surface facing an inner surface of the stent wall and defined in part by at least one blade angled with respect to the flow path, the rotor rotatably mounted on the stator between the inner surface of the stent and the stator, one of the rotor and the stator comprising a field magnet and the other of the rotor and the stator comprising windings;   operatively coupling a power source to the windings; and   controlling the power source to cause the rotor to rotate about a longitudinal axis.   
     
     
         21 . A ventricular assist device for a human heart, the device comprising:
 a stent, the stent sized for placement within a cardiac artery and arranged for placement at a selected location within the cardiac artery, the stent arranged to have an open configuration defining a flow path;   a rotor, the rotor sized to fit within the stent and arranged for percutaneous placement at the selected location and within the flow path, the rotor including a surface disposed about a central portion and angled with respect to the flow path, the rotor further defining a longitudinal axis and having a first plurality of magnets;   a collar, the collar sized for placement about the cardiac artery at the selected location, the collar comprising a stator having an electrical winding;   a power source operatively coupled to the stator;   the stator and the rotor arranged to interact in response to the application of power from the power source to the stator to cause the rotor to rotate about the longitudinal axis;   a timing control module, the timing control module operatively coupled to the stator and arranged to control a rotational speed of the rotor; and   wherein the surface of the rotor is arranged to move blood along the flow path in response to rotation of the rotor.   
     
     
         22 . The device of  claim 21 , wherein the stent includes a magnet set and the rotor includes a second plurality of magnets, the magnet set of the stent and the second plurality of magnets of the rotor cooperating to control a longitudinal position of the rotor with respect to the flow path. 
     
     
         23 . The device of  claim 21 , wherein the selected location can be both the aorta and the pulmonary artery. 
     
     
         24 . The device of  claim 23 , wherein the selected location is supravalvular. 
     
     
         25 . The device of  claim 21 , wherein the surface of the rotor is formed by a plurality of blades. 
     
     
         26 . The device of  claim 21 , wherein the surface of the rotor is helical. 
     
     
         27 . The device of  claim 21 , wherein the timing control module is operatively coupled to a sensor arranged to sense native cardiac rhythms, and wherein the timing module is arranged to control the rotational speed of the rotor in response to the native cardiac rhythms. 
     
     
         28 . The device of  claim 21 , wherein the timing control module is arranged to control the rotational speed of the rotor between a baseline speed and a higher speed, wherein the baseline speed is arranged to allow the device to function as a closed valve, and wherein the higher speed is arranged to move blood along the flow path at a desired flow rate. 
     
     
         29 . The device of  claim 21 , wherein one or both of the rotor and the stent are coated with an anti-coagulant. 
     
     
         30 . The device of  claim 21 , wherein the power source is arranged for subcutaneous placement. 
     
     
         31 . The device of  claim 30 , wherein the power source is arranged for transcutaneous charging. 
     
     
         32 . A ventricular assist device for a human heart, the device comprising:
 a stent, the stent sized for placement within a cardiac artery at a selected location within the cardiac artery, the stent arranged to define a flow path;   a magnetized rotor, the rotor sized to fit within the stent and at the selected location and within the flow path, the rotor including a surface angled with respect to the flow path, the rotor further including a longitudinal axis;   a collar, the collar sized for placement about the cardiac artery at the selected location, the collar comprising a stator having an electrical winding;   a power source operatively coupled to the stator;   the stator and the rotor arranged to interact in response to the application of power from the power source to the stator to cause the rotor to rotate about the longitudinal axis;   a timing control module, the timing control module operatively coupled to the stator and arranged to control a rotational speed of the rotor between a baseline first speed and a higher second speed; and   wherein the surface of the rotor is arranged to move blood along the flow path in response to rotation of the rotor.   
     
     
         33 . The device of  claim 32 , wherein the stent is shiftable between a collapsed configuration and an expanded configuration, the collapsed configuration allowing percutaneous placement of the stent at the desired location, the stent arranged to shift from the collapsed configuration to the expanded configuration when the stent defines the flow path. 
     
     
         34 . The device of  claim 33 , wherein the rotor is shiftable between a collapsed configuration and an expanded configuration, the collapsed configuration allowing percutaneous placement of the rotor within the stent at the desired location. 
     
     
         35 . The device of  claim 34 , wherein the rotor includes a plurality of blades, the blades arranged to expand when the rotor is shifted from the collapsed configuration to the expanded configuration. 
     
     
         36 . The device of  claim 32 , wherein the collar and the rotor include cooperating magnet sets, the magnet sets cooperating to control a longitudinal position of the rotor with respect to the stent along the flow path. 
     
     
         37 . The device of  claim 32 , wherein the selected location can be both the aorta and the pulmonary artery. 
     
     
         38 . The device of  claim 32 , wherein the selected location is supravalvular. 
     
     
         39 . The device of  claim 32 , wherein the timing control module is operatively coupled to a sensor arranged to sense native cardiac rhythms, and wherein the timing module is arranged to control the rotational speed of the rotor in response to the native cardiac rhythms. 
     
     
         40 . The device of  claim 32 , wherein the timing control module is arranged to control the rotational speed of the rotor between a baseline speed and a higher speed, wherein the baseline speed is arranged to allow the device to function as a closed valve, and wherein the higher speed is arranged to move blood along the flow path at a desired flow rate. 
     
     
         41 . The device of  claim 32 , wherein the timing control module is arranged to control the rotational speed of the rotor to create a first flow characteristic and a second flow characteristic, wherein the first flow characteristic creates at least a partial reverse flow, and wherein the second flow characteristic creates a forward flow. 
     
     
         42 . The device of  claim 32 , wherein one or both of the rotor and the stent are coated with an anti-coagulant. 
     
     
         43 . The device of  claim 32 , wherein the power source is arranged for subcutaneous placement. 
     
     
         44 . The device of  claim 43 , wherein the power source is a battery and is arranged for transcutaneous charging. 
     
     
         45 . The device of  claim 32 , wherein the timing control module is arranged for transcutaneous programming. 
     
     
         46 . The device of  claim 32 , wherein the collar is adapted for minimally invasive placement at the selected location. 
     
     
         47 . A method of implanting a ventricular assist device in a heart, comprising the steps of:
 selecting a stent sized for placement within a cardiac artery at a selected location within the cardiac artery;   placing the stent at the selected location in a collapsed configuration;   expanding the stent at the selected location to define a flow path through the stent;   providing a magnetized rotor sized to fit within the expanded stent at the selected location and within the flow path, and providing the rotor with a surface angled with respect to the flow path, the rotor further including a longitudinal axis;   placing a collar about the cardiac artery at the selected location, the collar comprising a stator having an electrical winding;   operatively coupling a power source to the stator;   arranging the stator and the rotor to interact in response to the application of power from the power source to the stator to cause the rotor to rotate about the longitudinal axis;   providing a timing control module operatively coupled to the stator and arranged to control a rotational speed of the rotor between a baseline first speed and a higher second speed; and   activating the rotor to move blood along the flow path in response to rotation of the rotor.   
     
     
         48 . The method of  claim 47 , wherein the selected location is in a pulmonary artery of the heart, and including directing at least a portion of the flow path toward an artificial lung. 
     
     
         49 . The method of  claim 47 , wherein the timing control module is arranged to rotate the rotor to create a reverse flow. 
     
     
         50 . The method of  claim 47 , including coupling the timing control module to a sensor, the sensor arranged to detect native cardiac rhythms, and arranging the timing control module to rotate the rotor to coincide with the native cardiac rhythms.