Patent Description:
Implantable blood pumps, such as intravascular and intraventricular blood pumps, may be miniaturized blood pumps used as mechanical circulatory support devices to move blood from the heart to the rest of the body. Intravascular blood pumps may be percutaneously or surgically implanted into a patient's vascular system to provide left heart support or right heart support. In the alternative, intraventricular blood pumps may be implanted into a ventricle of the patient to provide left heart support or right heart support. In operation, the blood pump includes an inflow portion that draws blood from a source, such as the right ventricle, left ventricle, right atrium, or left atrium of a patient's heart and impels the blood through an outflow portion into an artery, such as the patient's ascending aorta or peripheral artery. Known blood pumps may be limited to providing either left-side support or right-side support.

In addition to the inflow portion, and the outflow portion, blood pumps typically include a blood pump connected to a motor. In particular, the blood pump is disposed in a housing which also includes a rotating impeller to impel the blood. The impeller may include one or more vanes or flow channels to impel blood from the inflow portion to the outflow portion of the blood pump. The motor spins the impeller, thus providing the pumping action. Many known blood pumps connect the motor to the impeller using a connection system having a long and semi-rigid shaft that is difficult to align during implantation and through the vascular exit site. For example, in order to couple the blood pump to an exterior motor, known shafts may include a length that exceeds <NUM> centimeters, the average length of an ascending aorta in a human body. Such long and semi-rigid shafts do not sufficiently flex to allow the motor to move relative to the blood pump housing to selectively align the blood pump within a specified location of the heart. In addition, relatively long shafts pose a higher risk of infection and require frequent maintenance, such as added lubrication, to safeguard the integrity of shaft.

Herein is disclosed a pump to motor connection system for an implantable blood pump as defined in the appended claims.

A pump to motor connection system for an implantable blood pump including a pump housing having an impeller disposed therein and a motor housing having a motor disposed therein, the motor housing being spaced a distance from the pump housing. A flexible outer sheath couples the pump housing to the motor housing, the outer sheath defining a maximum total length between <NUM> and <NUM> centimeters. An inner shaft is coaxial with the outer sheath, the inner shaft coupling the motor to the and wherein the pump housing is sized to be received and configured to be implanted within the left ventricle and the motor housing is sized to be received and configured to be implanted within the ascending aorta; or wherein the pump housing is sized to be received and configured to be implanted within the right ventricle and the motor housing is sized to be received and configured to be implanted downstream of a pulmonary valve.

In another aspect of this embodiment, the system includes a motor shaft extending at least partially within the outer sheath.

In another aspect of this embodiment, the pump housing defines a total length between <NUM> and <NUM> centimeters.

In an additional aspect of this embodiment, the motor housing defines a total length between <NUM> and <NUM> centimeters.

In yet another aspect of this embodiment, the outer sheath includes a pliable member and a cover member surrounding the pliable member.

In another aspect of this embodiment, the inner shaft is flexible and includes a plurality of steel members defining a coil.

In an additional aspect of this embodiment, the outer sheath includes a proximal portion and a distal portion, the proximal portion being rigidly coupled to the pump housing and the distal portion being rigidly coupled to the motor housing, the pump housing being moveable relative to the motor housing.

In another aspect of this embodiment, the implantable blood pump includes a bearing and a thrust washer each coupled to the inner shaft.

In another aspect of this embodiment, the thrust washer defines a lubrication channel.

In another aspect of this embodiment, the outer sheath and the inner shaft define a conduit therebetween, the conduit including a biocompatible fluid retained therein.

A sheath movably couples the pump housing relative to the motor housing, the sheath made of a malleable material. A flexible inner shaft is coaxial with and moveable relative to the sheath, the inner shaft extending through the pump housing and being connected to the impeller and the motor.

In another aspect of this embodiment, the sheath defines a total length of <NUM> centimeters.

In yet another aspect of this embodiment, the sheath defines the distance between the pump housing and the motor housing.

In an additional aspect of this embodiment, the pump housing and the motor housing each define a length between <NUM> and <NUM> centimeters.

In another aspect of this embodiment, the inner sheath is made of a plurality of steel members defining a coil.

In another aspect of this embodiment, the pump housing and the motor housing are selectively moveable relative to the at least one of the group consisting of a chamber of a heart and a blood vessel exterior to the heart.

In another aspect of this embodiment, the at least one of the group consisting of a chamber of a heart and a blood vessel exterior to the heart includes a left ventricle and an aorta.

In yet another aspect of this embodiment, the system includes a bearing and a thrust washer each coupled to the inner shaft.

In another embodiment, the pump to motor connection system for an implantable blood pump includes a pump housing having an impeller and a diffuser disposed therein, the pump housing defining a maximum total length between <NUM> and <NUM> centimeters and a motor housing having a motor disposed therein, the motor housing defining a maximum total length between <NUM> and <NUM> centimeters and being moveable relative to the pump housing. The connection system also includes a flexible outer sheath having a proximal portion and a distal portion, the proximal portion extending from the pump housing and the distal portion extending from the motor housing, the outer sheath defining a maximum total length between <NUM> and <NUM> centimeters. A flexible inner shaft is coaxial with outer sheath, the inner shaft extending at least partially through the motor housing and being connected to the impeller, the diffuser, and the motor, the outer sheath and the inner shaft defining a conduit therebetween, the conduit including a biocompatible fluid retained therein.

Referring now to the drawings in which like reference designators refer to like elements there is shown in <FIG> an exemplary pump to motor connection system for an implantable blood pump constructed in accordance with the principles of the present application and designated generally "<NUM>. " The connection system <NUM> may include an implantable blood pump <NUM> that is intravascular and/or intraventricular, such as implanted within the vascular system and/or a ventricle of a mammalian heart, such as a human heart, to provide left and/or right heart support for a patient.

With reference to <FIG> and <FIG>, depicting a side view and a side cross-sectional view, respectively, the connection system <NUM> includes a pump housing <NUM> having an impeller <NUM> disposed therein and a motor housing <NUM> including a motor <NUM> disposed therein. The impeller <NUM> includes vanes and/or flow channels which rotate to impel blood from an inflow portion <NUM> to an outflow portion <NUM> of the pump housing <NUM>. Although <FIG> depicts the inflow portion <NUM> including a cannula tip <NUM> defining three inlet apertures <NUM> and an inflow cannula <NUM> coupled to the cannula tip <NUM>, other configurations of the inflow portion <NUM> may also be utilized with more or less inlet apertures <NUM>. The pump housing <NUM> defines the outflow portion <NUM> with an aperture for blood to exit the blood pump <NUM> and circulate throughout a patient's body.

The motor housing <NUM> may be spaced a distance from the pump housing <NUM>. As shown in <FIG>, the distance may be defined by a length of a flexible outer sheath <NUM>, generally designated as "SL", which couples the pump housing <NUM> to the motor housing <NUM>. For example, the outer sheath <NUM> may define a maximum total length between <NUM> and <NUM> centimeters. In one configuration, the total length of the outer sheath <NUM> is <NUM> centimeters.

The outer sheath <NUM> may include a tapered region which tapers in a direction toward the pump housing <NUM> to define a minor diameter, generally designated as "MND," between <NUM>-<NUM> centimeters and a major diameter, generally designated as "MJD," between <NUM>-. <NUM> centimeters. The outer sheath <NUM> allows the pump housing <NUM> to move relative to the motor housing <NUM> to assist with alignment during implantation of the blood pump <NUM>. For example, the outer sheath <NUM> may assist with aligning the blood pump <NUM> within a low curvature ascending aorta for left-side heart support and within a right atrium or vena cava for right-side heart support. Alignment within the heart may occur using a guide catheter or another method of implantation.

With reference to <FIG>, an inner shaft <NUM> may be disposed within the blood pump <NUM> that is coaxial with the outer sheath <NUM>. The inner shaft <NUM> may extend through the outer sheath <NUM> to couple the motor <NUM> to the impeller <NUM>, thus causing the motor <NUM> to rotate the impeller <NUM> to impel the blood. In one configuration, the motor <NUM> may include a motor shaft <NUM> extending from the motor housing <NUM> at least partially within the outer sheath <NUM>. The motor shaft <NUM> may be slidably received within a first channel <NUM> defined by a coupling member <NUM>, such as a support bracket, extending between the outer sheath <NUM> and the motor housing <NUM>. The coupling member <NUM> may define a second channel <NUM> for receiving the inner shaft <NUM>, such that the inner shaft <NUM> is in communication with the motor shaft <NUM> for rotation. In one configuration, an opposing end of the inner shaft <NUM> may be coupled to the impeller <NUM>, such as through welding. Other coupling arrangements between the inner shaft <NUM>, the motor <NUM>, and the impeller <NUM> may also be used, such as a slot and pin connection, bearings, and the like.

In one configuration, the motor <NUM> may be powered by a drive circuit (not shown) including electrical coils for applying electrical current to the motor <NUM>. Alternative power sources may also be utilized. In one configuration, the inner shaft <NUM> may also extend through a diffuser <NUM> disposed within the pump housing <NUM> to improve the hydraulic efficiency of the blood pump <NUM>. Similar to the outer sheath <NUM>, the inner shaft <NUM> may be flexible to provide for improved alignment within the heart during implantation. In one configuration, the diameter of the pump housing <NUM> and the motor housing <NUM> is between <NUM>-<NUM> centimeters, however the diameter may vary outside of this range.

The pump housing <NUM> and the motor housing <NUM> are sized to be received within a chamber of a heart and/or a blood vessel exterior to the heart. For example, the pump housing <NUM> and the motor housing <NUM> may each define a total length, generally designated as "PL" and "ML," respectively in <FIG>, between <NUM> and <NUM> centimeters. In one exemplary configuration, because the outer sheath <NUM> may define the maximum total length between <NUM> and <NUM> centimeters, the blood pump <NUM> may be implanted entirely within the left ventricle and an ascending aorta of an adult patient having an ascending aorta with an average length of approximately <NUM> centimeters. In one configuration, the pump housing <NUM> is sized to be received within the left ventricle and the motor housing <NUM> is sized to be received within the ascending aorta. In another example, the pump housing <NUM> is sized to be received within the right ventricle and the motor housing <NUM> is sized to be received downstream of a pulmonary valve. Additionally, the pump housing <NUM> is sized to be received within the left atrium, which may be beneficial for treating certain conditions, such as pulmonary hypertension. In another example, the pump housing <NUM> and the motor housing <NUM> are sized to be received within the heart with an outflow cannula being utilized to bridge the patient's aortic valve. Such examples are not intended to be limiting as the blood pump <NUM> is sized to be received in other configurations within the heart and the exterior blood vessel, depending on whether the patient would benefit from left and/or right heart support.

With reference to <FIG>, the outer sheath <NUM> may include a proximal portion <NUM> and a distal portion <NUM>. The proximal portion <NUM> may be rigidly coupled to the pump housing <NUM> and the distal portion <NUM> may be rigidly coupled to the motor housing <NUM>, such as through the use of welding, brackets, or another coupling mechanism which creates a rigid connection. In an exemplary configuration, the diffuser <NUM> may extend from the pump housing <NUM> and the proximal portion <NUM> of the outer sheath <NUM> may be coupled to the diffuser <NUM>. A bearing <NUM> and a thrust washer <NUM> may each be coupled to the inner shaft <NUM> to create a thrust bearing for supporting an axial force of the inner shaft <NUM>. The bearing <NUM> may bridge the connection between the diffuser <NUM> and the outer sheath <NUM>.

In one configuration, the outer sheath <NUM> and the inner shaft <NUM> define a conduit <NUM> therebetween for retaining a biocompatible fluid, such as dextrose, to add lubrication to the inner shaft <NUM>. A flexible seal <NUM> may be coupled to the diffuser <NUM> to contain the biocompatible fluid within the conduit <NUM>. As a further source of lubrication, the thrust washer <NUM> may define a pair of lubrication grooves <NUM> adjacent the inner shaft <NUM> which allow the fluid to surround and thus lubricate the inner shaft <NUM>. For example, as shown in the cross-sectional view of <FIG>, the lubrication grooves <NUM> may extend through the thrust washer <NUM>, thus permitting the fluid to travel along and around the inner shaft <NUM> for lubrication.

The outer sheath <NUM> may me made of a malleable material, such as a biocompatible polymeric material, stainless steel, or another material that flexes and bends to allow for alignment within the heart and/or the exterior blood vessel. For example, with reference to <FIG>, the outer sheath <NUM> may include a pliable member <NUM> (<FIG>), such as a spring, coil, or the like configured to be disposed within a cover member <NUM> (<FIG>). The cover member <NUM> may be a silicone mold which surrounds the pliable member <NUM> to preserve the integrity of the pliable member <NUM>, while permitting the flexing and bending.

In one configuration, as shown in <FIG>, the inner shaft <NUM> is coaxial with and moveable relative to the outer sheath <NUM> as a result of the inner shaft <NUM> being made of two or more steel members wound together to define a coil. In one configuration the inner shaft <NUM> may be made of an inner coil and an outer coil. For example, the inner coil may be made of a stainless-steel wire that is right-hand wound and the outer coil may be made of the stainless-steel wire that is left-hand wound to assist with providing appropriate torque for operation of the blood pump <NUM>. In addition, the materials forming the outer sheath <NUM> and the inner shaft <NUM> provide a surgeon with the ability to selectively move the pump housing <NUM> and the motor housing <NUM> relative to each other during implantation of the blood pump <NUM>.

Claim 1:
A pump to motor connection system for an implantable blood pump (<NUM>), comprising:
a pump housing (<NUM>) including an impeller (<NUM>) disposed therein;
a motor housing (<NUM>) including a motor disposed therein, the motor housing (<NUM>) being spaced a distance from the pump housing (<NUM>);
a flexible outer sheath (<NUM>) coupling the pump housing (<NUM>) to the motor housing (<NUM>), the outer sheath (<NUM>) defining a maximum total length between <NUM> and <NUM> centimeters; and
an inner shaft (<NUM>) coaxial with the outer sheath (<NUM>), the inner shaft (<NUM>) coupling the motor to the impeller (<NUM>);
wherein the pump housing (<NUM>) is sized to be received and configured to be implanted within the left ventricle and the motor housing (<NUM>) is sized to be received and configured to be implanted within the ascending aorta; or wherein the pump housing (<NUM>) is sized to be received and configured to be implanted within the right ventricle and the motor housing (<NUM>) is sized to be received and configured to be implanted downstream of a pulmonary valve.