Distal bearing support

Abstract

In various embodiments, a catheter pump is disclosed herein. The catheter pump can include an elongated catheter body having a distal portion including an expandable cannula having an inlet and an outlet. The expandable cannula can have a delivery profile and an operational profile larger than the delivery profile. An impeller assembly can include an impeller shaft, and an impeller body can include one or more blades. The impeller blades can draw blood into the cannula when rotated. Further, an expandable support can have a mounting portion disposed on the impeller shaft distal of the impeller body and a cannula contact portion for reducing a change in tip gap due to bending of the cannula. The cannula contact portion can be disposed distal of the mounting portion.

What is claimed is: 
     
         1 . A catheter pump, comprising:
 a motor;   an elongated catheter body coupled with the motor, the elongated catheter body comprising a distal portion;   an expandable cannula disposed at the distal portion and comprising an inlet, an outlet, and a cannula housing, the expandable cannula having a delivery profile and an operational profile larger than the delivery profile;   an impeller mounted on an impeller shaft coupled to the motor such that operation of the motor causes rotation of the impeller to draw blood into the expandable cannula, the impeller disposed within the cannula housing between the inlet and the outlet, the cannula housing having an operational profile inner diameter from a longitudinal axis of the impeller shaft; and   an expandable distal bearing support configured to provide radial support of the impeller shaft within the cannula housing, the expandable distal bearing support comprising a mounting portion and a support member, wherein the support member comprises:
 a proximal portion and a plurality of lobes expanding distally from the proximal portion, each of the plurality of lobes comprising distal struts coupled to proximal struts, the proximal struts coupled to and extending distally from the proximal portion; 
 wherein the distal struts comprise a distal end, the distal end having an inner diameter from the longitudinal axis of the impeller shaft; and 
 wherein the distal end inner diameter is greater than the cannula housing operational profile inner diameter. 
   
     
     
         2 . The catheter pump of  claim 1 , wherein each of the plurality of lobes is spaced circumferentially from each other. 
     
     
         3 . The catheter pump of  claim 1 , wherein the distal end of the distal struts is configured to contact an internal wall of the cannula housing at least when the expandable cannula has the operational profile and apply a radially outward force. 
     
     
         4 . The catheter pump of  claim 3 , wherein the applied radially outward force increases a bending stiffness of the cannula housing. 
     
     
         5 . The catheter pump of  claim 3 , wherein the distal end of the distal struts is configured to curve slightly inward toward the longitudinal axis of the impeller shaft to avoid cutting into the cannula housing. 
     
     
         6 . The catheter pump of  claim 1 , wherein the motor is disposed at a proximal end of the elongated catheter body, wherein the motor is configured to remain remote from the impeller and to remain outside a patient. 
     
     
         7 . The catheter pump of  claim 1 , wherein the cannula housing comprises a mesh. 
     
     
         8 . The catheter pump of  claim 7 , wherein the mesh is denser at a support region of the cannula housing that contacts the distal end of the distal struts. 
     
     
         9 . The catheter pump of  claim 1 , wherein the mounting portion of the expandable distal bearing support comprises a cylindrical member disposed on the impeller shaft of the impeller in a manner permitting the impeller shaft to rotate therein. 
     
     
         10 . The catheter pump of  claim 9 , wherein the impeller shaft has an enlarged diameter at a distal end thereof and the cylindrical member has a diameter less than the enlarged diameter at the proximal end thereof. 
     
     
         11 . The catheter pump of  claim 9 , wherein the cylindrical member comprises an enlarged distal portion having an inner diameter greater than an enlarged diameter at the distal end of the impeller shaft. 
     
     
         12 . The catheter pump of  claim 1 , wherein the impeller is expandable. 
     
     
         13 . The catheter pump of  claim 1 , wherein each of the plurality of lobes comprises an elongate member extending from the proximal portion of the support member. 
     
     
         14 . The catheter pump of  claim 1 , wherein each of the plurality of lobes comprises a concave portion disposed between the proximal portion of the support member and a respective free end of the plurality of lobes. 
     
     
         15 . The catheter pump of  claim 14 , wherein the concave portion is curved inwards towards an interior of the expandable cannula. 
     
     
         16 . The catheter pump of  claim 8 , wherein each of the plurality of lobes comprises a convex portion in contact with the support region of the cannula housing. 
     
     
         17 . The catheter pump of  claim 16 , wherein the convex portion is curved outwards towards the cannula housing. 
     
     
         18 . The catheter pump of  claim 17 , wherein the convex portion is not rigidly fixed to an internal wall of the cannula housing to allow for relative movement between the plurality of lobes and the cannula housing. 
     
     
         19 . The catheter pump of  claim 1 , wherein the support member deploys into a flower-shape with the plurality of lobes forming a flower petal shape. 
     
     
         20 . The catheter pump of  claim 1 , wherein the plurality of lobes comprises four lobes.