Intravascular blood pump

Abstract

An intravascular blood pump having a rotatable shaft carrying an impeller and a housing with an opening through which the shaft extends with the impeller positioned outside the housing. The shaft and the housing have surfaces forming a circumferential gap which converges towards the impeller-side end of the gap and which has a minimum gap width of preferably no more than 5 μm, more preferably no more than 2 μm.

1 - 15 . (canceled) 
     
     
         16 . An intravascular blood pump comprising:
 a shaft carrying an impeller, the shaft being rotatable; and   a housing having an opening and an end wall having a sleeve,   a circumferential gap defined by a circumferential surface of the shaft and a surface of the sleeve;   wherein the shaft extends through the opening with the impeller positioned outside the housing; and   wherein the circumferential gap has a length and a width, the width having a minimum width selected to provide a physical barrier against ingress of red blood cells into the gap.   
     
     
         17 . The intravascular blood pump according to  claim 16 , wherein the sleeve is a ceramic sleeve comprising a sintered ceramic material or silicon carbide. 
     
     
         18 . The intravascular blood pump according to  claim 16 , wherein at least one of the shaft, the sleeve or the end wall comprises a thermoconductive material. 
     
     
         19 . The intravascular blood pump according to  claim 18 , wherein the end wall of the housing further comprises one or more radially outer thermoconductive elements. 
     
     
         20 . The intravascular blood pump according to  claim 19 , wherein the radial outer thermoconductive element is thermoconductively connected to the sleeve. 
     
     
         21 . The intravascular blood pump according to  claim 19 , wherein the one or more radially outer thermoconductive elements have a thermal conductivity that is higher than a thermal conductivity of the sleeve. 
     
     
         22 . The intravascular blood pump according to  claim 16 , wherein the minimum width is located somewhere within 50% of the length of the gap closest to an impeller-side end of the gap. 
     
     
         23 . The intravascular blood pump according to  claim 22 , wherein the minimum width extends over 30% or less of the length of the gap. 
     
     
         24 . The intravascular blood pump according to  claim 23 , wherein the minimum width extends over not more than 20% of the length of the gap. 
     
     
         25 . The intravascular blood pump according to  claim 16 , wherein the length of the gap is in a range of from 1 to 2 mm. 
     
     
         26 . The intravascular blood pump according to  claim 25 , wherein the length of the gap is in the range of from 1.3 to 1.7 mm. 
     
     
         27 . The intravascular blood pump according to  claim 16 , wherein the circumferential gap converges continuously over at least part of its length up to where the gap has the minimum width. 
     
     
         28 . The intravascular blood pump according to  claim 16 , wherein the circumferential gap converges linearly over at least part of its length. 
     
     
         29 . The intravascular blood pump according to  claim 16 , wherein a diameter of the circumferential gap converges towards an impeller-side end which is an end of the circumferential gap closest to the impeller. 
     
     
         30 . The intravascular blood pump according to  claim 16 , wherein an outer diameter of the shaft expands towards an impeller-side end which is an end of the circumferential gap closest to the impeller. 
     
     
         31 . The intravascular blood pump according to  claim 30 , wherein the outer diameter of the shaft has a circumferential groove stretching over an end of the gap opposite the impeller-side end of the circumferential gap. 
     
     
         32 . The intravascular blood pump according to  claim 30 , wherein the outer diameter of the shaft expands from a constant diameter shaft section stretching over an end of the circumferential gap opposite the impeller-side end of the circumferential gap to a maximum outer diameter within the gap. 
     
     
         33 . The intravascular blood pump according to  claim 16 , wherein the minimum width of the gap is 5 μm or less. 
     
     
         34 . The intravascular blood pump according to  claim 33 , wherein the minimum width of the gap is 4 μm or less. 
     
     
         35 . The intravascular blood pump according to  claim 34 , wherein the minimum width of the gap is 3 μm or less. 
     
     
         36 . The intravascular blood pump according to  claim 35 , wherein the minimum width of the gap is 2 μm or less. 
     
     
         37 . The intravascular blood pump according to  claim 16 , wherein a maximum width of the gap is 15 μm or less. 
     
     
         38 . The intravascular blood pump according to  claim 22 , wherein the minimum width is present at the impeller-side end of the gap.