ROTATIONAL ATHERECTOMY DEVICE WITH ELECTRIC MOTOR

• US 20110213391A1
• Filed: 02/26/2010
• Published: 09/01/2011
• Est. Priority Date: 02/26/2010
• Status: Active Grant

• Current Assignee: Cardiovascular Systems Incorporated (Abbott Laboratories)
• Original Assignee: Cardiovascular Systems Incorporated (Abbott Laboratories)
• Inventors: Eng, Michael John, Plowe, Charles A., Hanson, Scott M., Piippo Svendsen, Cassandra Ann, Dobrovolny, Walter John, Rivers, Jody Lee
• Granted Patent: US 9,050,126 B2
• Time in Patent Office: Days
• US Class Current: 606/159
• CPC Class Codes: A61B 17/320758 with a rotating cutting instrument, e.g. motor driven A61B17/320725, A61B17/32075 and A61B17/320783 take precedence; for removing intra-ocular material A61F9/00763; endoscopic rotatable cutting instruments A61B17/32002
• CPC Class Codes: A61B 2017/00075 Motion
• CPC Class Codes: A61B 2017/00199 with a console, e.g. a control panel with a display
• CPC Class Codes: A61B 2017/320004 abrasive
• CPC Class Codes: A61B 2017/320766 eccentric
• CPC Class Codes: A61B 2090/066 for measuring torque

Abstract

An atherectomy device is disclosed, which is rotationally driven by an electric motor. In some designs, the device includes features unavailable on gas turbine-driven systems, such as the storing in memory of low/medium/high preset rotation speeds for particular models of handle, calculations of the amount of saline left in the IV and associated warnings when it gets sufficiently low, and automatic adjustment of the IV pump rate to a predetermined or calculated level when the rotational speed of the motor is changed. The electric motor has far more rotational inertia than a comparable gas turbine, so the system includes a control mechanism that helps prevent damage from excessive torque being applied to the distal end of the drive shaft. When an obstruction at the distal end is detected, by a drop in the motor rotational speed, the motor is released and is allowed to spin freely as a flywheel. The freely-spinning motor allows the large angular momentum of the system to dissipate rapidly and safely, without excessive torque to the drive shaft.

Claims

1. A rotational atherectomy system, comprising:

an elongated, flexible drive shaft having a distal end for insertion into a vasculature of a patient and having a proximal end opposite the distal end remaining outside the vasculature of the patient;

an eccentric solid crown attached to the drive shaft proximate the distal end of the drive shaft;

an electric motor rotatably coupled to the proximal end of the drive shaft, the electric motor being capable of rotating the drive shaft in a first direction and in a second direction opposite the first direction; and

control electronics for monitoring and controlling the rotation of the electric motor, wherein the control electronics detect when the drive shaft and eccentric solid crown encounter a blockage in the vasculature that rapidly slows their rotation and control the rotational speed and torque of the drive shaft in response to the blockage, and

wherein the drive shaft and eccentric solid crown, when rotating, have a torque limited by a current supplied to the electric motor.

2. The rotational atherectomy system of claim 1, wherein the control electronics include limits on maximum and minimum rotational speeds of the electric motor.

3. The rotational atherectomy system of claim 1, wherein the control electronics include limits on maximum and minimum current supplied to the electric motor.

4. The rotational atherectomy system of claim 1, wherein the control electronics include limits on maximum and minimum torque delivered by the electric motor.

5. The rotational atherectomy system of claim 1, wherein the control electronics use a change in at least one of rotational speed, current and voltage to determine when an atherectomy has reached a milestone.

6. The rotational atherectomy system of claim 1,

wherein the electric motor is contained within a handle;

and

wherein the control electronics are contained in a control unit separate from the handle and electrically tethered to the handle.

7. The rotational atherectomy system of claim 6, wherein the control unit includes internal memory for storing performance specifications.

8. The rotational atherectomy system of claim 6, wherein the control unit includes an external activation control and an external electric motor rotational speed control.

9. The rotational atherectomy system of claim 6, wherein the control unit is simultaneously operable with an electronic heart defibrillator.

10. The rotational atherectomy system of claim 6, wherein the control unit includes a void detector that ensures reliable delivery of saline to the vasculature of the patient.

11. The rotational atherectomy system of claim 1,

wherein the eccentric solid crown has a center of mass that is laterally displaced from a rotational axis of the drive shaft;

and

wherein the eccentric solid crown includes an abrasive exterior surface.

12. A rotational atherectomy system, comprising:

an elongated, flexible drive shaft having a distal end for insertion into a vasculature of a patient and having a proximal end opposite the distal end remaining outside the vasculature of the patient;

an eccentric solid crown attached to the drive shaft proximate the distal end of the drive shaft;

an electric motor rotatably coupled to the proximal end of the drive shaft, the electric motor being capable of rotating the drive shaft in a first direction and in a second direction opposite the first direction;

a handle housing the electric motor;

control electronics for monitoring and controlling the rotation of the electric motor, the control electronics that detect when the drive shaft and eccentric solid crown encounter a blockage in the vasculature that rapidly slows their rotation and control the rotational speed and torque of the drive shaft in response to the blockage; and

a control unit separate from the handle and electrically tethered to the handle.

13. The rotational atherectomy system of claim 12, wherein the control unit includes internal memory for storing performance specifications.

14. The rotational atherectomy system of claim 12, wherein the control unit includes an external activation control and an external electric motor rotational speed control.

15. The rotational atherectomy system of claim 12, wherein the control unit is simultaneously operable with an electronic heart defibrillator.

16. The rotational atherectomy system of claim 12, wherein the control unit includes a void detector that ensures reliable delivery of saline to the vasculature of the patient.

17. The rotational atherectomy system of claim 12,

wherein the eccentric solid crown has a center of mass that is laterally displaced from a rotational axis of the drive shaft;

and

wherein the eccentric solid crown includes an abrasive exterior surface.

18. The rotational atherectomy system of claim 12, wherein the control electronics use a change in at least one of rotational speed, current and voltage to determine when an atherectomy has reached a milestone.

19. A rotational atherectomy system, comprising:

an elongated, flexible drive shaft having a distal end for insertion into a vasculature of a patient and having a proximal end opposite the distal end remaining outside the vasculature of the patient;

an eccentric solid crown attached to the drive shaft proximate the distal end of the drive shaft;

an electric motor rotatably coupled to the proximal end of the drive shaft, the electric motor being capable of rotating the drive shaft in a first direction and in a second direction opposite the first direction; and

control electronics for monitoring and controlling the rotation of the electric motor;

wherein the drive shaft and eccentric solid crown, when rotating, have a torque limited by a current supplied to the electric motor;

wherein the control electronics detect when the drive shaft and eccentric solid crown encounter a blockage in the vasculature that rapidly slows their rotation and control the rotational speed and torque of the drive shaft in response to the blockage;

wherein the control electronics include limits on maximum and minimum rotational speeds of the electric motor;

wherein the control electronics include limits on maximum and minimum current supplied to the electric motor;

wherein the control electronics include limits on maximum and minimum torque delivered by the electric motor; and

wherein the control unit includes a void detector that ensures reliable delivery of saline to the vasculature of the patient.

20. The rotational atherectomy system of claim 19,

wherein the eccentric solid crown has a center of mass that is laterally displaced from a rotational axis of the drive shaft;

and

wherein the eccentric solid crown includes an abrasive exterior surface.

21. The rotational atherectomy system of claim 19, wherein the control electronics use a change in at least one of rotational speed, current and voltage to determine when an atherectomy has reached a milestone.

22. A rotational atherectomy system, comprising:

an elongated, flexible drive shaft having a distal end for insertion into a vasculature of a patient and having a proximal end opposite the distal end remaining outside the vasculature of the patient;

an abrasive element attached to the drive shaft proximate the distal end of the drive shaft;

an electric motor rotatably coupled to the proximal end of the drive shaft, the electric motor being capable of rotating the drive shaft; and

control electronics for monitoring and controlling the rotation of the electric motor, the control electronics including an algorithm for limiting the torque on the drive shaft when the abrasive element encounters an obstruction and ceases rotation, the algorithm comprising;

detecting a decrease in the rotational speed of the electric motor; and

releasing the motor, thereby allowing the motor to spin freely as a flywheel.

23. The rotational atherectomy system of claim 22, wherein the decrease in the rotation speed comprises a drop of a predetermined amount below a desired rotational speed.

24. The rotational atherectomy system of claim 22, wherein the decrease in the rotation speed comprises a drop of a predetermined percentage below a desired rotational speed.

25. The rotational atherectomy system of claim 22, wherein the decrease in the rotation speed comprises a drop of a predetermined variable percentage below a desired rotational speed, the variable percentage depending on the desired rotational speed.

26. The rotational atherectomy system of claim 22, wherein detecting the decrease in the rotational speed of the electric motor comprises:

receiving periodic signals from at least one Hall effect sensor on the electric motor; and

sensing a decrease in periodic signal rate from the Hall effect sensor.

27. The rotational atherectomy system of claim 22, wherein the decrease in periodic signal rate comprises a predetermined variable percentage that depends on the desired rotational speed.