Flexing axial shaft

Abstract

Apparatus and methods are described including a ventricular assist device configured to assist ventricular functioning of a subject. The ventricular assist device includes an impeller and a frame disposed around the impeller. An axial shaft extends from a proximal end of the frame to a distal end of the frame, the impeller being coupled to the axial shaft. The axial shaft includes a proximal portion and a distal portion, which are coupled to each other via a joint. The proximal portion and the distal portion of the axial shaft are configured to flex with respect to each other via the joint. Other applications are also described.

1 . An apparatus, comprising:
 a ventricular assist device configured to assist ventricular functioning of a subject, the ventricular assist device comprising:
 an impeller; 
 a frame disposed around the impeller; 
 an axial shaft extending from a proximal end of the frame to a distal end of the frame, the impeller being coupled to the axial shaft, and the axial shaft comprising a proximal portion and a distal portion, which are coupled to each other via a joint, 
 the proximal portion and the distal portion of the axial shaft being configured to flex with respect to each other via the joint. 
   
     
     
         2 . The apparatus according to  claim 1 , wherein the frame has a length of more than 25 mm. 
     
     
         3 . The apparatus according to  claim 1 , wherein the joint is disposed within a portion of the axial shaft that is proximal to the impeller. 
     
     
         4 . The apparatus according to  claim 1 , wherein the joint is disposed within a portion of the axial shaft that is distal to the impeller. 
     
     
         5 . The apparatus according to  claim 1 , wherein the joint is disposed within a portion of the axial shaft around which the impeller is disposed. 
     
     
         6 . The apparatus according to  claim 1 , wherein the joint comprises a cardan joint. 
     
     
         7 . The apparatus according to  claim 1 , wherein the left-ventricular assist device further comprises a proximal radial bearing disposed at the proximal end of the frame, and a distal radial bearing disposed at the distal end of the frame, and the axial shaft extends from the proximal radial bearing to the distal radial bearing. 
     
     
         8 . The apparatus according to  claim 7 , wherein the joint is configured to allow the axial shaft to conform with a curvature of the frame, such that if the frame becomes curved, the proximal portion of the axial shaft is disposed coaxially with respect to the proximal radial bearing and the distal portion of the axial shaft is disposed coaxially with respect to the distal radial bearing. 
     
     
         9 . The apparatus according to  claim 1 , wherein the impeller comprises a proximal bushing and a distal bushing which are disposed around the axial shaft. 
     
     
         10 . The apparatus according to  claim 9 , wherein at least one of the proximal and distal bushings is coupled to the axial shaft. 
     
     
         11 . The apparatus according to  claim 9 , wherein the impeller further comprises:
 a spring disposed between the proximal bushing and the distal bushing;   one or more helical elongate elements disposed around the spring; and   an elastomer extending from the one or more helical elongate elements to the spring such as to define one or more impeller blades.   
     
     
         12 . The apparatus according to  claim 9 , wherein the joint is disposed within a portion of the axial shaft that is disposed between the proximal bushing and the distal bushing of the impeller. 
     
     
         13 . An apparatus, comprising:
 a ventricular assist device configured to assist ventricular functioning of a subject, the ventricular assist device comprising:
 an impeller; 
 a frame disposed around the impeller; 
 a proximal radial bearing disposed at the proximal end of the frame, and a distal radial bearing disposed at the distal end of the frame; and 
 an axial shaft extending from the proximal radial bearing to the distal radial bearing, 
 the axial shaft comprising a proximal portion and a distal portion which are configured to flex with respect to each other to allow the axial shaft to conform with a curvature of the frame, such that if the frame becomes curved, the proximal portion of the axial shaft is disposed coaxially with respect to the proximal radial bearing and the distal portion of the axial shaft is disposed coaxially with respect to the distal radial bearing. 
   
     
     
         14 . The apparatus according to  claim 13 , wherein the frame has a length of more than 25 mm. 
     
     
         15 . The apparatus according to  claim 13 , wherein a proximal portion and a distal portion of the axial shaft are coupled to each other via a joint, and the proximal portion and the distal portion of the axial shaft are configured to flex with respect to each other via the joint. 
     
     
         16 . The apparatus according to  claim 15 , wherein the joint is disposed within a portion of the axial shaft that is proximal to the impeller. 
     
     
         17 . The apparatus according to  claim 15 , wherein the joint is disposed within a portion of the axial shaft that is distal to the impeller. 
     
     
         18 . The apparatus according to  claim 15 , wherein the joint is disposed within a portion of the axial shaft around which the impeller is disposed. 
     
     
         19 . The apparatus according to  claim 15 , wherein the joint comprises a cardan joint. 
     
     
         20 . The apparatus according to  claim 15 , wherein the impeller comprises a proximal bushing and a distal bushing which are disposed around the axial shaft. 
     
     
         21 . The apparatus according to  claim 20 , wherein at least one of the proximal and distal bushings is coupled to the axial shaft. 
     
     
         22 . The apparatus according to  claim 20 , wherein the impeller further comprises:
 a spring disposed between the proximal bushing and the distal bushing;   one or more helical elongate elements disposed around the spring; and   an elastomer extending from the one or more helical elongate elements to the spring such as to define one or more impeller blades.   
     
     
         23 . The apparatus according to  claim 20 , wherein the joint is disposed within a portion of the axial shaft that is disposed between the proximal bushing and the distal bushing of the impeller.