Flexible catheter with a drive shaft
The invention relates to a flexible catheter ( 1 ) with a drive shaft ( 2 ), with a sleeve ( 6 ) surrounding the drive shaft ( 2 ) and with a sheath ( 7 ) surrounding the drive shaft ( 2 ) and the sleeve ( 6 ), wherein the drive shaft, the sleeve ( 6 ) and the sheath ( 7 ) are pliable, wherein the drive shaft ( 2 ) at a proximal end of the drive shaft ( 2 ) comprises a coupling element ( 5 ) for connecting the drive shaft ( 2 ) to a drive motor ( 18 ), wherein the drive shaft ( 2 ) at least regionally consist of a alloy which contains at least 10% by weight of chromium, nickel and cobalt in each case. The invention moreover relates to a blood pump arrangement with such a catheter.
1. A flexible catheter comprising:
a drive shaft;
a sleeve surrounding the drive shaft; and
a sheath surrounding the drive shaft and the sleeve,
wherein the drive shaft, the sleeve, and the sheath are configured to be flexible, and the drive shaft, at a proximal end of the drive shaft, has a coupling element for connecting the drive shaft with a drive motor, and the drive shaft consists at least partially of an alloy which comprises at least 10% by weight of chromium, nickel and cobalt,
wherein the sleeve is configured as a bearing coil with a plurality of windings, each winding of the plurality of windings rotating helically around the drive shaft in an axial direction.
2. The catheter according to claim 1 , wherein the alloy comprises at least one of:
(i) 30%-40% by weight nickel,
(ii) 30%-40% by weight cobalt, and
(iii) 15%-25% by weight chromium.
3. The catheter according to claim 1 , wherein the alloy has a tensile strength between 1800 N/mm 2 and 2400 N/mm 2 .
4. The catheter according to claim 3 , wherein the sleeve is at least partially made from the alloy that has the tensile strength between 1800 N/mm 2 and 2400 N/mm 2 .
5. The catheter according to claim 1 , wherein the sleeve is at least partially made of a same material as the drive shaft.
6. The catheter according to claim 1 , wherein the bearing coil comprises a wound ribbon.
7. The catheter according to claim 6 , wherein an axially measured width of turns of the bearing coil lies in a range of 0.36 mm to 0.84 mm or that a radially measured thickness of the turns of the bearing coil lies in a range of 0.06 mm to 0.14 mm.
8. The catheter according to claim 6 , wherein the windings of the bearing coil, when in a straight condition without curvature, has an axial tilting of less than 5° relative to the axial direction.
9. The catheter according to claim 6 , wherein lateral edges of the ribbon are rounded.
10. The catheter according to claim 9 , wherein the lateral edges of the ribbon have a curvature radius of 0.04 mm or more.
11. The catheter according to claim 1 , wherein a slope of the bearing coil lies in a range of 0.43 to 0.98.
12. The catheter according to claim 1 , wherein an inner diameter of the sleeve lies in a range between 0.6 mm and 1.4 mm or an outer diameter the sleeve lies in a range of 0.72 mm to 1.68 mm.
13. The catheter according to claim 1 , wherein a surface of the drive shaft has a roughness RZ between 0.01 microns and 1 micron.
14. A blood pump assembly with a catheter, comprising:
a blood pump;
a drive shaft;
a sleeve surrounding the drive shaft; and
a sheath surrounding the drive shaft and the sleeve,
wherein the drive shaft, the sleeve, and the sheath are configured to be flexible, and the drive shaft, at a proximal end of the drive shaft, has a coupling element for connecting the drive shaft with a drive motor, and the drive shaft consists at least partially of an alloy which comprises at least 10% by weight of chromium, nickel, and cobalt,
wherein the sleeve is configured as a bearing coil with a plurality of windings, each winding of the plurality of windings rotating helically around the drive shaft in an axial direction.
15. The blood pump assembly of claim 14 , wherein the blood pump assembly further comprises a drive motor, wherein there is a non-rotatable and axially displaceable connection between the drive motor and the coupling element of the drive shaft.
16. The blood pump assembly of claim 14 , wherein the alloy comprises at least one of:
(i) 30%-40% by weight nickel,
(ii) 30%-40% by weight cobalt, and
(iii) 15%-25% by weight chromium.
17. The blood pump assembly of claim 14 , wherein the alloy has a tensile strength between 1800 N/mm 2 and 2400 N/mm 2 .
18. The blood pump assembly of claim 14 , wherein the sleeve is at least partially made of a same material as the drive shaft.