Search

US-20260124442-A1 - EXTERNAL DRIVE UNIT FOR AN IMPLANTABLE HEART ASSIST PUMP

US20260124442A1US 20260124442 A1US20260124442 A1US 20260124442A1US-20260124442-A1

Abstract

An external drive unit for an implantable heart assist pump is provided. The drive unit comprises a motor housing, a transcutaneous drive shaft and a motor for driving the heart assist pump. The motor is connectable to the heart assist pump via the drive shaft, and the motor is arranged inside the motor housing. The drive unit further comprises a catheter surrounding the drive shaft and a purge line for injecting a purge medium into a lumen of the catheter or into a space between the catheter and the drive shaft. The purge line is in thermal contact with an outer surface of the motor housing and/or with an outer surface of a proximal section of the catheter. Due to the thermal contact heat is transferred from the outer surface of the catheter in the proximal section and/or from the outer surface of the motor housing to the purge medium.

Inventors

  • Gerd Spanier
  • Maxim Daschewski

Assignees

  • ECP ENTWICKLUNGSGESELLSCHAFT MBH

Dates

Publication Date
20260507
Application Date
20250702
Priority Date
20170822

Claims (19)

  1. 1 - 19 . (canceled)
  2. 20 . An external drive unit for an implantable heart assist pump comprising: an external drive unit housing comprising: a motor housing; a transcutaneous drive shaft; a motor comprising a rotor rotatably mounted on a proximal bearing and a distal bearing within the motor housing; a catheter rigidly connected to the external drive unit housing; and a supply line comprising a purge line, wherein the purge line is configured to guide a purge medium such that: the purge medium first comes into thermal contact with at least one of an outer surface of the motor housing or an outer surface of a proximal section of the catheter, and the purge medium is afterwards injected into a lumen of the catheter or into a space between the catheter and the drive shaft.
  3. 21 . The external drive unit of claim 20 , wherein the supply line further comprises electrical leads to supply electricity to the motor.
  4. 22 . The external drive unit of claim 20 , wherein the external drive unit further comprises inductors.
  5. 23 . The external drive unit of claim 22 , wherein the inductors are located inside the housing of the external drive unit.
  6. 24 . The external drive unit of claim 22 , wherein the inductors are located at an end of the supply line.
  7. 25 . The external drive unit of claim 20 , wherein the motor comprises a stator and a rotor connected to the drive shaft, wherein the rotor is rotatably mounted and wherein a fluid gap is formed between the rotor and the stator, wherein the fluid gap is in fluid connection with a purge opening for injecting the purge medium into the fluid gap, and wherein the purge line is configured to connect to the purge opening.
  8. 26 . The external drive unit of claim 25 , wherein a width of the fluid gap in a radial direction may be between 0.2 and 0.3 mm.
  9. 27 . The external drive unit of claim 20 , wherein the supply line exits the housing at a distal end of the housing.
  10. 28 . The external drive unit of claim 27 , wherein the supply line enters the external drive housing in-line with the transcutaneous drive shaft.
  11. 29 . The external drive unit of claim 20 , further comprising a thermal insulator arranged between the supply line and the external drive unit housing.
  12. 30 . The external drive unit of claim 20 , wherein an overall thermal conductance between an interior surface of the purge line and an interior surface of the motor housing may amount to at least five times an overall thermal conductance between the interior surface of the purge line and an interior surface of the external drive unit housing.
  13. 31 . The external drive unit of claim 30 , wherein the overall thermal conductance between the interior surface of the purge line and the interior surface of the motor housing may amount to at least ten times the overall thermal conductance between the interior surface of the purge line and the interior surface of the external drive unit housing.
  14. 32 . The external drive unit of claim 20 , further comprising a heat spreader comprising a contact surface configured to contact a skin of a patient, wherein the contact surface is configured to connect with the motor in a thermally-conductive manner to transfer heat generated by the motor to tissue of the patient.
  15. 33 . The external drive unit of claim 32 , wherein the heat spreader is flexible at least in an area.
  16. 34 . The external drive unit of claim 33 , wherein the heat spreader further comprises a series of openings for the transfer of vaporized sweat.
  17. 35 . The external drive unit of claim 32 , wherein the heat spreader is further connected to a heat sink of a console.
  18. 36 . The external drive unit of claim 32 , wherein the housing further contains cooling fins.
  19. 37 . The external drive unit of claim 20 , wherein the motor is connected to the transcutaneous drive shaft via a coupling.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation of U.S. application Ser. No. 18/639,196, filed on Apr. 18, 2024, which is allowed, which is a divisional of U.S. application Ser. No. 16/603,527, filed on Oct. 7, 2019, now issued as U.S. Pat. No. 11,986,609, which application is a national phase entry under 35 U.S.C. § 371 of International Application No. PCT/EP 2018/058941 filed on Apr. 6, 2018, published in English, which claims priority from U.S. application Ser. No. 15/482,513, filed on Apr. 7, 2017, now issued as U.S. Pat. No. 10,926,013, European Patent Application Nos. 17187359.9, filed on Aug. 22, 2017, and 17187358.1, filed on Aug. 22, 2017, the disclosures of which are hereby incorporated herein by reference. BACKGROUND OF THE INVENTION The present application relates to the field of medical technology. The application relates to an external drive unit for an implantable heart assist pump and to a heart assist device comprising the drive unit and the implantable heart assist pump. The present application is related to assignee's U.S. application Ser. No. 15/482,513, filed Apr. 7, 2017, entitled “Methods and Systems for an External Drive Unit for an Implantable Heart Assist Pump”, which is hereby incorporated by reference. BRIEF SUMMARY OF THE INVENTION Heart assist devices for assisting a heart function of a patient are known from the state of the art. Such devices may comprise an implantable blood pump, which may be inserted into a ventricle of the heart by minimally invasive means. Further, an external (or extracorporal) motor may be supplied to drive the blood pump. The motor may be connected with the blood pump via a transcutaneous and flexible drive shaft which may be rotatably mounted inside a transcutaneous catheter. The implantable components of the device may be inserted via a puncture site in a patient's groin. A related device is described, e.g., in U.S. Pat. No. 8,489,190 B2. For such heart assist devices problems may arise relating to heat dissipated by the external motor. In some applications, the motor may be disposed close to the patient's body, in particular close to the patient's leg, while the blood pump is operated. If heat generated by the motor is not effectively removed the motor may overheat, which may cause malfunction of the motor. In addition, overheating of the motor may constitute a health risk to the patient when a hot housing of the motor contacts the skin of the patient, in particular when the patient is not able to notice the heat and to react appropriately, e.g., due to anesthetic medication. Safe amounts of heat absorption by a human skin have been studied in the context of heat generated by ultrasound and magnetic resonance imaging probes. For example, in “Human Skin Temperature Response to Absorbed Thermal Power” (SPIE Proceedings-The International Society for Optical Engineering 3037:129-134, March 1997) a method is described to determine safe levels of heat absorption. To prevent the motor of the heart assist device from overheating, the housing of such a motor may be equipped with a multitude of cooling fins so that heat is effectively withdrawn from the motor and dissipated to the surrounding air. However, the amount of heat transferrable to the air may not be sufficient if the motor is operated in an enclosed environment, e.g., underneath a duvet while the patient rests or underneath surgical drapery during surgery. In addition, a surface of the housing with cooling fins may be difficult to clean. In view of the aforementioned state of the art, it is an objective of the present application to provide an improved external drive unit for an implantable heart assist pump and an improved heart assist device. In particular, it is an objective of the application to provide a drive unit and a heart assist device with an improved heat management. Further, it is an objective of the application to suggest a drive unit which enables a safe and efficient operation of the heart assist device. These objectives are achieved by an external drive unit with the features of independent claim 1. Optional further features and further developments will become apparent from the dependent claims and the detailed description in conjunction with the accompanying drawings. The proposed external, i.e., extracorporal, drive unit for an implantable heart assist pump comprises a motor housing, a transcutaneous drive shaft and a motor for driving the heart assist pump. The motor is connectable to the heart assist pump via the drive shaft, and the motor is arranged inside the motor housing. The drive unit further comprises a catheter surrounding the drive shaft and a purge line for injecting a purge medium into a lumen of the catheter or into a space between the catheter and the drive shaft. The purge medium may be a solution, e.g., a glucose solution or saline solution. The purge line is in thermal contact with an outer surface of the motor housing and/or with an