Tube with blood-inlet openings

Abstract

Apparatus and methods are described including a left-ventricular assist device that includes an impeller configured to be placed inside a subject's left ventricle and to pump blood from the left ventricle to the subject's aorta, by rotating. A frame is disposed around the impeller. A tube traverses the subject's aortic valve, such that a proximal portion of the tube is disposed within the aorta and a distal portion of the tube is disposed within the left ventricle. The distal portion of the tube extends to the distal end of the frame and defines more than 10 blood-inlet openings that are sized such as (a) to allow blood to flow from the subject's left ventricle into the tube and (b) to block structures from the subject's left ventricle from entering into the frame. Other applications are also described.

1 . An apparatus, comprising:
 a left-ventricular assist device comprising:
 an impeller configured to be placed inside a left ventricle of a subject and to pump blood from the left ventricle to an aorta of the subject, by rotating; 
 a frame disposed around the impeller; and 
 a tube configured to traverse an aortic valve of the subject, such that a proximal portion of the tube is disposed within the subject's aorta and a distal portion of the tube is disposed within the subject's left ventricle, 
 the distal portion of the tube extending to a distal end of the frame and defining more than 10 blood-inlet openings that are sized such as (a) to allow blood to flow from the subject's left ventricle into the tube and (b) to block structures from the subject's left ventricle from entering into the frame. 
   
     
     
         2 . The apparatus according to  claim 1 , wherein the frame is shaped such that, in a non-radially constrained configuration of the frame, the frame defines a proximal conical portion, a central cylindrical portion, and a distal conical portion, wherein the distal portion of the tube extends distally over the distal conical portion of the frame, and wherein at least some of the blood-inlet openings are at least partially disposed over the distal conical portion of the frame. 
     
     
         3 . The apparatus according to  claim 1 , wherein at least a portion of the tube is collapsible, such that:
 in response to pressure outside of the portion of the tube exceeding pressure inside the collapsible portion of the tube, the collapsible portion of the tube collapses inwardly, and   during operation of the impeller, pressure of the blood flow through the tube maintains the collapsible portion of the tube in an open state.   
     
     
         4 . The apparatus according to  claim 1 , wherein each of the blood-inlet openings defines an area of less than 1 square mm. 
     
     
         5 . The apparatus according to  claim 1 , wherein the blood-inlet openings are shaped such as to block chordae tendineae, trabeculae carneae, and papillary muscles of the subject from entering into the frame and to thereby prevent the chordae tendineae, trabeculae carneae, and papillary muscles from being damaged by the impeller during rotation of the impeller. 
     
     
         6 . The apparatus according to  claim 1 , wherein the left-ventricular assist device further comprises an axial shaft, the impeller being disposed on the axial shaft, and wherein the blood-inlet openings are shaped such as to block chordae tendineae, trabeculae carneae, and papillary muscles of the subject from entering into the frame and to thereby prevent the chordae tendineae, trabeculae carneae, and papillary muscles from being damaged by the axial shaft during rotation of the impeller. 
     
     
         7 . The apparatus according to  claim 1 , wherein the ventricular assist device further comprises a structure configured to separate the blood-inlet openings from the internal structures of the ventricle, the structure being selected from the group consisting of: a braid and a mesh. 
     
     
         8 . The apparatus according to  claim 1 , wherein the tube defines more than 50 blood-inlet openings. 
     
     
         9 . The apparatus according to  claim 8 , wherein the tube defines more than 100 blood-inlet openings. 
     
     
         10 . The apparatus according to  claim 1 , wherein the blood-inlet openings are shaped such that a ratio of lengths to widths of each of the blood-inlet openings is between 1.1:1 and 4:1. 
     
     
         11 . The apparatus according to  claim 10 , wherein the lateral blood inlet openings are shaped such that a ratio of lengths to widths of each of the blood-inlet openings is between 3:2 and 5:2. 
     
     
         12 . The apparatus according to  claim 1 , wherein the proximal portion of the tube defines one or more blood-outlet openings that are configured to allow blood to flow from the tube into the subject's aorta. 
     
     
         13 . The apparatus according to  claim 12 , wherein the tube defines a generally-cylindrical central portion, and a proximal conical portion that narrows from a proximal end of the central portion to a proximal end of the tube, and wherein the one or more blood-outlet openings extend at least partially into the proximal conical portion of the tube. 
     
     
         14 . The apparatus according to  claim 12 , wherein the blood-outlet openings are teardrop shaped. 
     
     
         15 . The apparatus according to  claim 12 , wherein the tube defines between two and eight blood-outlet openings. 
     
     
         16 . The apparatus according to  claim 15 , wherein the tube defines between two and four blood-outlet openings. 
     
     
         17 . The apparatus according to  claim 1 , wherein a region of the tube that defines the blood-inlet openings has a porosity of more than 40 percent. 
     
     
         18 . The apparatus according to  claim 17 , wherein a region of the tube that defines the blood-inlet openings has a porosity of more than 50 percent. 
     
     
         19 . The apparatus according to  claim 1 , wherein each of the blood-inlet openings defines a span of less than 1 mm in at least one direction. 
     
     
         20 . The apparatus according to  claim 19 , wherein each of the blood-inlet openings defines a span of less than 0.8 mm in the at least one direction. 
     
     
         21 . The apparatus according to  claim 20 , wherein each of the blood-inlet openings defines a span of less than 0.3-0.8 mm in the at least one direction. 
     
     
         22 . A method, comprising:
 placing a left-ventricular assist device into a subject such that:
 an impeller of the left-ventricular assist device is placed inside a left ventricle of a subject; 
 a frame of the left-ventricular assist device is disposed around the impeller; and 
 a tube of the left-ventricular assist device traverses an aortic valve of the subject, such that a proximal portion of the tube is disposed within an aorta of the subject and a distal portion of the tube is disposed within the subject's left ventricle, and 
 driving the impeller to rotate such as to pump blood from the subject's left ventricle to the subject's aorta, 
 wherein the distal portion of the tube extends to a distal end of the frame and defines more than 10 blood-inlet openings that are sized such as (a) to allow blood to flow from the subject's left ventricle into the tube and (b) to block structures from the subject's left ventricle from entering into the frame.