US-20260124441-A1 - CARDIOVASCULAR SUPPORT PUMP HAVING AN IMPELLER WITH A VARIABLE FLOW AREA

Abstract

The present disclosure is directed generally to mechanical cardiovascular support systems used in the medical field to assist the movement of blood. In particular the present disclosure is directed to an impeller having features that allow improved performance. An annular flow area around a rotating impeller may be variable along the axial length of the impeller. A first radial gap, between a distal region of the impeller and a surrounding tubular housing, may be greater or smaller than a second radial gap, between a proximal region of the impeller and the surrounding tubular housing.

Inventors

• Johannes Bette
• Vladimir Popov
• Marvin Mitze

Assignees

• KARDION GMBH

Dates

Publication Date

20260507

Application Date

20260105

Claims (17)

1. 1 . A mechanical circulatory support device comprising: a tubular cannula comprising an inflow region, an outflow region, and a distal impeller region, and an impeller having a proximal end and a distal end, the impeller being positioned within the tubular cannula at least partly in the outflow region and at least partly in the distal impeller region, wherein a radial gap between the impeller and an inner surface of the tubular cannula varies in size between the proximal end and the distal end, wherein the size of the radial gap at a particular location between the proximal end and the distal end comprises a radial distance between a maximum impeller width and the inner surface of the tubular cannula at the particular location, wherein the impeller comprises a constant diameter section having a first diameter, and wherein the impeller comprises a proximal narrowed diameter section proximal to the constant diameter section, the proximal narrowed diameter section having a narrowed diameter less than the first diameter.
2. 2 . The device of claim 1 , wherein the constant diameter section extends at least partially within the distal impeller region and at least partially into the outflow region.
3. 3 . The device of claim 1 , wherein the constant diameter section is positioned fully in the distal impeller region.
4. 4 . The device of claim 1 , wherein the radial gap is between 0.040 mm and 0.200 mm at a location of the first diameter.
5. 5 . The device of claim 1 , wherein the radial gap is between 0.070 mm and 0.100 mm at the location of the first diameter.
6. 6 . The device of claim 1 , wherein a transition between the proximal narrowed diameter section and the constant diameter section comprises a taper.
7. 7 . The device of claim 6 , wherein the taper comprises a linear slope.
8. 8 . The device of claim 7 , wherein a slope of the linear slope is in a range of 0.011 to 2.
9. 9 . The device of claim 1 , wherein the narrowed diameter is between 0.15 mm and 0.35 mm less than the first diameter.
10. 10 . The device of claim 1 , wherein a transition between the proximal narrowed diameter section and the constant diameter section comprises a step transition.
11. 11 . The device of claim 1 , wherein a transition between the proximal narrowed diameter section and the constant diameter section comprises a gradual slope.
12. 12 . The device of claim 11 , wherein the gradual slope has a ratio of change in diameter to length of slope of between 0.011 and 2.
13. 13 . The device of claim 11 , wherein the gradual slope is curved.
14. 14 . The device of claim 11 , wherein the gradual slope comprises an inflection.
15. 15 . The device of claim 14 , wherein the gradual slope comprises multiple inflections.
16. 16 . The device of claim 1 , wherein the proximal narrowed diameter section is positioned entirely in the outflow region.
17. 17 . The device of claim 1 , wherein the proximal narrowed diameter section has a constant diameter equal to the narrowed diameter.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation application of U.S. Non-Provisional application Ser. No. 18/026,082, filed Mar. 13, 2023, which is claims the priority benefit of PCT No. PCT/US2021/071419, filed Sep. 10, 2021, which claims the priority benefit of U.S. Provisional Patent Application No. 63/078,207, filed Sep. 14, 2020, the entire disclosure of which are hereby incorporated by reference herein in their entireties. BACKGROUND Technical Field The present disclosure is directed generally to mechanical cardiovascular support systems used in the medical field to assist the movement of blood. In particular, the present disclosure is directed to mechanical cardiovascular support devices having features that allow improved performance such as optimized flow area between impeller blades or shafts or other components and a surrounding inlet tube, or optimized space between certain stationary and moving parts. Description of the Related Art Mechanical circulatory support devices are used to assist a patient's heart with moving blood through the body. They often consist of an electrical motor, a tubular inflow canula with an inflow area at the distal end and an outflow area at the proximal end, and an impeller rotated by the motor that moves blood through the tubular inflow cannula and out through the outflow area. A particular design challenge is to optimize blood flow while minimizing risk of damage to the device or to the blood. A higher blood flow than what is provided by current devices may improve outcomes for mild cardiogenic shock patients or high-risk percutaneous coronary intervention patients. However, increasing flow may also increase risk of hemolysis or device damage. Thus, there is a need for improved mechanical circulatory support designs that can allow for greater blood flow while avoiding risk of hemolysis or device damage, among other improvements. SUMMARY This disclosure is related to mechanical circulatory support systems having an impeller with a variable outer diameter or having a variable radial gap between the impeller blades or other components of and impeller and a tubular cannula containing the impeller. The embodiments disclosed herein each have several aspects no single one of which is solely responsible for the disclosure's desirable attributes. Without limiting the scope of this disclosure, its more prominent features will now be briefly discussed. After considering this discussion, and particularly after reading the section entitled “Detailed Description,” one will understand how the features of the embodiments described herein provide advantages over existing systems, devices, and methods for mechanical circulatory support systems. The following disclosure describes non-limiting examples of some embodiments of mechanical circulatory support devices. For instance, other embodiments of the disclosed systems and methods may or may not include the features described herein. Moreover, disclosed advantages and benefits can apply only to certain embodiments and should not be used to limit the disclosure. One aspect of the disclosure is a mechanical circulatory support device including: a tubular cannula including an inflow region, an outflow region, and a distal impeller region, and an impeller having a proximal end and a distal end, the impeller being positioned within the tubular cannula at least partly in the outflow region and at least partly in the distal impeller region, wherein a radial gap between the impeller and an inner surface of the tubular cannula varies in size between the proximal end and the distal end, wherein the size of the radial gap at a particular location between the proximal end and the distal end includes a radial distance between a maximum impeller width and the inner surface of the tubular cannula at the particular location. A 2nd aspect of the disclosure relates to the device of aspect 1, wherein the impeller includes a distally tapered section tapering distally from a first diameter to a distal diameter, wherein the distal diameter is less than the first diameter. A 3rd aspect of the disclosure relates to the device of aspect 2, wherein the impeller includes a constant diameter section extending proximally from the distally tapered section, the constant diameter section having the first diameter. A 4th aspect of the disclosure relates to the device of aspect 3, wherein the constant diameter section extends at least partially within the distal impeller region and at least partially into the outflow region. A 5th aspect of the disclosure relates to the device of either aspect 3 or aspect 4, wherein the constant diameter section extends from the distally tapered section to the proximal end of the impeller. A 6th aspect of the disclosure relates to the device of either aspect 3 or aspect 4, wherein the impeller includes a proximal narrowed diameter section proximal to the constant diameter section, the proximal narrowed diamet