Blood pump

A method of providing blood circulation for a surgical patient, comprising the steps of:

• (a) providing an intravascular blood pump, comprising:
• a cable assembly having:
• an outer sheath;
• an inner sheath partially enclosed within the outer sheath;
• and
• a drive cable partially enclosed within the inner sheath;
• and
• a pump mechanism comprising
• an outer sleeve having a first port therein and being attached to the outer sheath;
• an inner sleeve in sliding engagement with the outer sleeve, the inner sleeve being attached to the inner sheath and at least partly defining a second port distally located relative to the first port;
• and
• an impeller mounted within the inner sleeve, the impeller being attached to the drive cable;
• the pump mechanism being movable between a retracted position wherein at least one of the first and second ports is sealed by one of the inner and outer sleeves, and an extended position wherein the first and second ports are open to permit fluid communication with the impeller;
• (b) making an incision at the apex of the heart;
• (c) while maintaining the intravascular blood pump in its retracted position to close at least one of the first and second ports, inserting the blood pump through the incision;
• (d) placing the intravascular blood pump in it extended position and causing a portion of the inner sleeve to pass through one of the heart valves so that the second port is on the opposite side of the heart valve relative to the first port;
• and
• (e) rotating the drive cable to thereby rotate the impeller to circulate blood.

An intravascular blood pump, comprising:

• a driver;
• and
• a pump mechanism comprising:
• inner and outer sleeves in sliding interengagement, one of the inner and outer sleeves including a port, and the other of the inner and outer sleeves being movable relative to the port between a first position sealing the port and a second position wherein the port is open;
• an impeller mounted within at least one of the inner and outer sleeves the impeller being operatively connected to the driver to rotate the impeller to pump fluid through the port;
• and
• a controller operatively connected to the inner and outer sleeves to move them between the first and second positions.

An intravascular blood pump adapted to be inserted into a heart via the apex of the heart, the blood pump comprising:

• a cable assembly having:
• an outer sheath;
• an inner sheath partially enclosed within the outer sheath;
• and
• a drive cable partially enclosed within the inner sheath;
• and
• a pump mechanism comprising:
• an inner sleeve operatively connected to the inner sheath;
• a distal member operatively connected to the inner sleeve and/or the inner sheath;
• an outer sleeve having an inlet port therein, the outer sleeve being in sliding engagement with the inner sleeve and operatively connected to the outer sheath such that axial movement of the outer sheath relative to the inner sheath moves the outer sleeve axially relative to the inner sleeve between
• a closed position in which the inlet port is sealed by the inner sleeve and the outer sleeve sealingly engages the distal member;
• and
• an open position in which the inlet port is not sealed by the inner sleeve and the outer sleeve is spaced from the distal member to define an outlet port between the distal member and the outer sleeve;
• and
• an impeller mounted within at least one of the inner and outer sleeves, the impeller being operatively connected to the drive cable so that the impeller is rotated when the drive cable rotates.

An intravascular blood pump comprising:

• a sheath having a flange, the sheath comprising:
• an internal lumen;
• a bearing portion generally adjacent the flange, the bearing having:
• an end;
• at least one slot extending substantially between the flange and the end;
• and
• at least one channel along the end of the bearing portion providing fluid communication between the internal lumen and the slot;
• a drive cable partially enclosed within the internal lumen of the sheath;
• an impeller mounted on the drive cable so that the impeller is rotated when the drive cable rotates, the impeller having a cap receiving the bearing portion of the sheath, the cap slideably engaging the end of the bearing portion for rotation relative to the bearing portion, the cap having a flange disposed adjacent but not contacting the flange of the sheath to form a gap permitting the escape of fluid from the layer of fluid between the cap and bearing portion to purge the gap of blood;
• and
• means for introducing a flow of fluid into the lumen of the sheath so that the flow of fluid passes through the slot to provide a layer of fluid between the cap and the bearing portion.

An intravascular blood pump comprising:

• a pump housing having a central axis, and an inlet and an outlet defining upstream and downstream directions;
• an inlet flow straightener within the housing downstream of the inlet for aligning blood entering the pump housing via the inlet with the central axis;
• an impeller within the housing downstream of the inlet flow straightener, the impeller being mounted for rotation to pump blood from the inlet to the outlet;
• and
• an outlet flow straightener within the housing downstream of the impeller, the outlet flow straightener including vanes extending substantially from the impeller substantially to the outlet, the vanes curving from a relatively radial orientation with respect to the central axis to a relatively axial orientation with respect to the central axis to decrease the circumferential component of the velocity of the blood before the blood exists the outlet;
• wherein the pump housing is generally cylindrical, the outlet extends generally circumferentially around the pump housing, and the pump housing forms a generally conical or frustoconical structure adjacent the outlet opening to encourage radially outward flow of blood through the outlet.