Percutaneous circulatory assist device including a guidewire distal tip portion - Patent Application 20070122997

Abstract

The percutaneous circulatory assist device includes a housing and an impeller disposed within the housing. The impeller is rotatable relative to the housing such that blood flows through the housing. A cannula is coupled to the housing and a distal tip portion is coupled to the cannula opposite the housing. The distal tip portion includes an inner molded core configured to maintain a predetermined shape of the distal tip portion and an outer layer disposed outwardly from the inner molded core, or the distal tip portion includes an atraumatic spherical distal tip.

Description

[Technical Field]

[0001] The present disclosure relates to percutaneous circulatory assist devices. More particularly, the present disclosure relates to percutaneous circulatory assist devices that include a flexible distal tip. [Background technology]

[0002] Percutaneous circulatory assist devices, such as blood pumps, can provide temporary assistance for patients with impaired cardiac function or cardiac output for up to about several weeks. Several problems can complicate the delivery and operation of blood pumps within the heart, including difficulty in guidewire advancement, trauma to cardiac tissue, and vibration and / or movement of the blood pump, which can result in reduced performance of the blood pump. Summary of the Invention

[0003] In Example 1, a percutaneous circulatory assist device includes a housing, an impeller disposed within the housing and rotatable relative to the housing so that blood flows through the housing, a cannula coupled to the housing, and a distal tip portion coupled to the cannula on an opposite side from the housing, the distal tip portion including an inner molding core configured to maintain a predetermined shape of the distal tip portion, and an outer layer disposed outward from the inner molding core.

[0004] In Example 2, in the percutaneous circulatory assist device described in Example 1, the distal tip portion comprises a proximal section having a first stiffness and a distal section having a second stiffness, the second stiffness being less than the first stiffness.

[0005] In Example 3, the percutaneous circulatory assist device of Example 1 or 2, wherein the inner molded core comprises steel. In Example 4, the percutaneous circulatory assist device according to any one of Examples 1 to 3, wherein the inner molding core comprises a shape memory material.

[0006] In Example 5, the percutaneous circulatory assist device according to any one of Examples 1 to 4, wherein the outer layer comprises a radiopaque material. In Example 6, the percutaneous circulatory assist device according to any one of Examples 1 to 5, wherein the distal tip portion further comprises an atraumatic spherical distal tip.

[0007] In Example 7, in the percutaneous circulatory assist device according to any one of Examples 1 to 6, the device can be used without an auxiliary guidewire. In Example 8, in the percutaneous circulatory assist device according to any one of Examples 1 to 6, the device can be used together with an auxiliary guide wire.

[0008] In Example 9, the percutaneous circulatory assist device comprises a housing, an impeller disposed within the housing and rotatable relative to the housing so that blood flows through the housing, a cannula coupled to the housing, and a distal tip portion coupled to the cannula opposite the housing, the distal tip portion comprising an atraumatic spherical distal end.

[0009] In Example 10, in the percutaneous circulatory assist device described in Example 9, the distal tip portion comprises a proximal section having a first stiffness and a distal section having a second stiffness, the second stiffness being less than the first stiffness.

[0010] In Example 11, the percutaneous circulatory assist device of Example 9 or 10, wherein the distal tip portion comprises a shape memory material. In Example 12, the percutaneous circulatory assist device according to any one of Examples 9 to 11, wherein the distal tip portion comprises steel.

[0011] In Example 13, the percutaneous circulatory assist device according to any one of Examples 9 to 12, wherein the distal tip portion comprises a radiopaque material. In Example 14, in the percutaneous circulatory assist device according to any one of Examples 9 to 13, the device can be used without an auxiliary guide wire.

[0012] In Example 15, in the percutaneous circulatory assist device according to any one of Examples 9 to 13, the device can be used together with an auxiliary guide wire. In Example 16, a percutaneous circulatory assist device includes a housing having an inlet and an outlet, an impeller disposed within the housing and rotatable relative to the housing such that blood flows into the inlet, passes through the housing, and out the outlet, a cannula coupled to the housing, and a distal tip portion coupled to the cannula on the opposite side of the housing, the distal tip portion including an inner molding core configured to maintain a predetermined shape of the distal tip portion, and an outer layer disposed outward from the inner molding core.

[0013] In Example 17, in the percutaneous circulatory assist device described in Example 16, the distal tip portion comprises a proximal section having a first stiffness and a distal section having a second stiffness, the second stiffness being less than the first stiffness.

[0014] In Example 18, the percutaneous circulatory assist device of Example 16, wherein the inner molded core comprises steel. In Example 19, the percutaneous circulatory assist device of Example 18, wherein the outer layer comprises a radiopaque material.

[0015] In Example 20, the percutaneous circulatory assist device of Example 19, wherein the distal tip portion further comprises an atraumatic spherical distal tip. In Example 21, the percutaneous circulatory assist device of Example 18, wherein the distal tip portion further comprises an atraumatic spherical distal tip.

[0016] In Example 22, the percutaneous circulatory assist device of Example 16, wherein the distal tip portion further comprises an atraumatic spherical distal tip. In Example 23, the percutaneous circulatory assist device of Example 22, wherein the outer layer comprises a radiopaque material.

[0017] In Example 24, the percutaneous circulatory assist device of Example 16, wherein the outer layer comprises a radiopaque material. In Example 25, a percutaneous circulatory assist device comprises a housing having an inlet and an outlet, an impeller disposed within the housing and rotatable relative to the housing such that blood flows into the inlet, passes through the housing, and out the outlet, a cannula coupled to the housing, and a distal tip portion coupled to the cannula on the opposite side from the housing, the distal tip portion comprising an atraumatic spherical distal end.

[0018] In Example 26, in the percutaneous circulatory assist device described in Example 25, the distal tip portion comprises a proximal section having a first stiffness and a distal section having a second stiffness, the second stiffness being less than the first stiffness.

[0019] In Example 27, the percutaneous circulatory assist device of Example 25, wherein the distal tip portion comprises a shape memory material. In Example 28, the percutaneous circulatory assist device of Example 25, wherein the distal tip portion comprises steel.

[0020] In Example 29, the percutaneous circulatory assist device of Example 25, wherein the distal tip portion comprises a radiopaque material. In Example 30, a method of placing a blood pump in a subject, the blood pump comprising a cannula and a distal tip portion coupled to the cannula, the distal tip portion including an inner molding core configured to maintain a predetermined shape of the distal tip portion and an outer layer disposed outwardly from the inner molding core, the method including advancing the blood pump through the vasculature of the subject and using the blood pump to cross the aortic valve of the subject such that the distal tip portion is positioned within the left ventricle of the subject.

[0021] In Example 31, the method of Example 30, wherein advancing the blood pump through the vasculature of the subject includes advancing the blood pump without the use of an auxiliary guidewire.

[0022] In Example 32, the method of Example 30, wherein advancing the blood pump through the vasculature of the subject includes advancing the distal tip portion over an auxiliary guidewire. In Example 33, the method of Example 30, wherein crossing the aortic valve includes configuring the distal tip portion in a prolapsed configuration.

[0023] In Example 34, the method of Example 30 is performed, wherein the distal tip portion comprises a proximal section having a first stiffness and a distal section having a second stiffness, the second stiffness being less than the first stiffness.

[0024] In Example 35, the method of Example 30, wherein the distal tip portion further comprises an atraumatic spherical distal tip. While multiple embodiments are disclosed, still other embodiments of the present invention will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments of the invention. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive. [Brief explanation of the drawings]

[0025] [Figure 1] FIG. 1 is a partial side view of an exemplary percutaneous circulatory assist device (also referred to herein interchangeably as a "blood pump") positioned within a patient's aorta and heart, according to an embodiment of the subject matter disclosed herein. [Figure 2] 2 is another partial side view of the percutaneous circulatory assist device of FIG. 1. [Figure 3] 2 is a partial cross-sectional side view of the percutaneous circulatory assist device of FIG. 1. [Figure 4] FIG. 10 is a partial side view of another exemplary percutaneous circulatory assist device according to an embodiment of the subject matter disclosed herein. [Figure 5] FIG. 10 is a partial cross-sectional side view of yet another percutaneous circulatory assist device according to an embodiment of the subject matter disclosed herein. DETAILED DESCRIPTION OF THE INVENTION

[0026] While the present invention is susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and are described in detail below. It is not, however, the intention to limit the invention to the particular embodiments described. On the contrary, the invention is intended to cover all modifications, equivalents, and alternatives falling within the scope of the invention as defined by the appended claims.

[0027] FIG. 1 illustrates a portion of an exemplary percutaneous mechanical circulatory assist device 100 (also referred to interchangeably herein as a "blood pump") according to an embodiment of the subject matter disclosed herein, and its relative location within a human heart 10. The blood pump 100 may be delivered percutaneously by passing through the aorta 12 and positioned with the heart 10 relative to the aortic valve 14 and left ventricle 16, as shown in FIG. 1. In some embodiments, as described in further detail below, the blood pump 100 may provide improved trackability and may be delivered without the use of an auxiliary guidewire (not shown, i.e., a guidewire separate from the blood pump 100). Alternatively, the blood pump 100 may be delivered using an auxiliary guidewire.

[0028] Continuing to refer to FIG. 1 , blood pump 100 generally includes a flexible distal tip portion 102 (sometimes referred to as a “guidewire tip”), a cannula 104, an impeller portion 106, and a catheter 108. Cannula 104 may have a flexible structure to facilitate delivery of blood pump 100. Cannula 104 includes one or more blood inlets 110 located at its distal portion 112, and one or more blood outlets 114 located on a housing 116 of impeller portion 106. Housing 116 carries an impeller 118 that rotates relative to housing 116 to force blood into inlet 110, through housing 116, and out outlet 114. In operation, as shown in FIG. 1 , blood pump 100 is positioned within heart 10 such that inlet 110 is located within left ventricle 16 and outlet 114 is located within aorta 12. As a result, rotation of the impeller 118 relative to the housing 116 forces blood from the left ventricle 16 through the cannula 104 and impeller portion 106 and into the aorta 12. The flexible distal tip portion 102 is described in more detail below. However, during operation, the blood pump 100 may be positioned such that the distal tip portion 102 is adjacent to or in contact with the wall of the left ventricle 16, for example, at the apex 18 of the left ventricle 16.

[0029] 2 shows a side view of a portion of blood pump 100, specifically, distal portion 112 of cannula 104 and distal tip portion 102. Distal tip portion 102 includes a proximal section 120 adjacent cannula 104 and a distal section 122 adjacent proximal section 120 and opposite cannula. In some embodiments, as shown, proximal section 120 has a generally straight shape and distal section 122 has a generally curved shape. In other embodiments, proximal section 120 and / or distal section 122 have different shapes.

[0030] In some embodiments, the proximal section 120 of the distal tip portion 102 is configured to have a relatively high stiffness (compared to the distal section 122) so that it can withstand forces acting on the distal tip portion 102 and the blood pump 100. Such stiffness also provides axial strength, which facilitates placement and support of the cannula 104 within the left ventricle. The stiffness of the proximal section 120 can be achieved by constructing the proximal section 120 from one or more materials of appropriate hardness, by including structures such as reinforcing structures or slots within the proximal section 120, by combining materials and structures to achieve the appropriate stiffness, and / or by using other techniques known to those skilled in the art.

[0031] In some embodiments, the distal section 122 of the distal tip portion 102 is configured to have a relatively low stiffness (compared to the proximal section 120). Such stiffness facilitates atraumatic contact with tissue and also provides sufficient structural strength to position and support the cannula 104 within the left ventricle while also being able to absorb forces acting on the distal tip portion 102. The stiffness of the distal section 122 can be achieved by constructing the distal section 122 from one or more materials of appropriate hardness, by including structures such as reinforcing structures or slots within the distal section 122, by combining materials and structures to achieve the appropriate stiffness, and / or by using other techniques known to those skilled in the art. In general, the distal section 122 can be constructed from a material having a lower stiffness, as measured by, for example, durometer, than the stiffness of the material forming the proximal section 120. In some embodiments, depending on the material used for the reinforcing structure, the inclusion of such a structure can aid in visualization of the distal tip portion 102 under fluoroscopy.

[0032] As described above, the proximal section 120 of the distal tip portion 102 can have a greater stiffness than the distal section 122 of the distal tip portion 102. In some embodiments, the one or more stiffness transitions may occur in discrete steps along the length of the distal tip portion 102. In some embodiments, the one or more stiffness transitions may be gradual or continuous along the length of the distal tip portion 102. In other embodiments, the one or more stiffness transitions may be a combination of discrete steps and continuous segments. In some embodiments, the one or more stiffness transitions may be achieved by decreasing the wall thickness of the distal tip portion 102 from the proximal section 120 to the distal section 122, by decreasing the stiffness of the material along the length of the distal tip portion 102 without using separate segments, or by any other method known to one skilled in the art.

[0033] FIG. 3 shows a side cross-sectional view of a section of the distal tip portion 102. In some embodiments, as shown, the distal tip portion 102 includes multiple components or layers. More specifically, the distal tip portion 102 can include an inner molding core 124 and an outer layer 126 disposed outside the inner molding core 124. The inner molding core 124 can be constructed from one or more materials (e.g., shape memory materials) configured to maintain a predetermined shape of the distal tip portion 102. In some embodiments, the inner molding core 124 can be constructed from one or more metals, such as steel, e.g., spring steel, or stainless steel. In some embodiments, the inner molding core 124 can be constructed from one or more materials configured to be shaped by a user, such as a physician. In some embodiments, the inner molding core 124 can be a stamped ribbon. In some embodiments, the outer layer 126 can be constructed from one or more polymers (e.g., polyether block amide, thermoplastic polyurethane, etc.). In some embodiments, the outer layer 126 can be constructed from one or more radiopaque materials.

[0034] The distal tip portion 102 can provide one or more of a variety of additional advantages. For example, if the cannula 104 is configured to be flexible, blood flow and cardiac contractions can cause movement or vibration of the blood pump 100 within the heart. The flexible distal tip portion 102 can account for and reduce or counteract lateral contractile forces acting on the distal tip portion 102 during left ventricular contraction. The distal tip portion 102 can significantly reduce such movement or vibration, for example, by contacting the wall or surface of the left ventricle, thereby stabilizing the entire blood pump 100. Such stabilization of the blood pump 100 can increase the efficiency, performance, and / or lifespan of the blood pump 100. As another example, the distal tip portion 102 can facilitate traversing the aortic valve when in the prolapsed configuration of the distal tip portion 102 (i.e., with the distal end 128 ( FIG. 2 ) of the distal tip portion 102 facing away from the aortic valve). As a further example, the inclusion of the distal tip portion 102 as described above can enable the blood pump 100 to be advanced through a subject's vasculature, cross the aortic valve, and delivered to the left ventricle without the use of an auxiliary guidewire.

[0035] FIG. 4 shows a side view of a portion of a blood pump 200 in accordance with an embodiment of the subject matter disclosed herein. Specifically, FIG. 4 shows a distal portion 212 of a cannula 204 and a distal tip portion 202 of the blood pump 200. The cannula 204 may be the same as or similar to the cannula 104 described above. The distal tip portion 202 may be the same as or similar to the distal tip portion 102 described above, except that the distal tip portion 202 includes an enlarged, atraumatic distal tip 228. Specifically, the distal tip portion 202 includes an atraumatic, spherical distal tip 228. As shown, the spherical distal tip 228 can have a relatively large diameter compared to the diameter or width of the remainder of the distal tip portion 202.

[0036] In some embodiments, the distal tip portion may include a lumen to facilitate passage of an auxiliary guidewire. For example, referring now to FIG. 5 , a distal tip portion 302 of a blood pump 300 according to an embodiment of the subject matter disclosed herein is shown. The distal tip portion 302 includes an inner molded core 324 and an outer layer 326 disposed outside the inner molded core 324. The inner molded core 324 includes an inner lumen 330 that can accept an auxiliary guidewire 332. In some embodiments, the auxiliary guidewire 332 can straighten the curved shape of the distal tip portion 302. As an additional or alternative feature, the distal tip portion may include one or more active steering devices (not shown, such as push wires, pull wires, etc.) for straightening the curved shape. In either case, such features facilitate advancement and proper placement of the distal tip portion and blood pump within a subject.

[0037] Various modifications and additions can be made to the exemplary embodiments described without departing from the scope of the present invention. For example, while the above embodiments refer to particular features, the scope of the present invention also includes embodiments having different combinations of features and embodiments that do not include all of the described features. Accordingly, the scope of the present invention is intended to embrace all such alternatives, modifications, and variations that fall within the scope of the claims, together with all equivalents thereof.

Claims

1. The housing and an impeller disposed within the housing and rotatable relative to the housing to cause blood to flow through the housing; a cannula coupled to the housing; a distal tip portion coupled to the cannula opposite the housing, a user-shapeable metal inner molding core configured to be shaped by a user to maintain a predetermined shape of the distal tip portion; an outer layer disposed outwardly from the inner molding core; a distal tip portion including: A percutaneous circulatory assist device comprising:

2. 10. The percutaneous circulatory assist device of claim 1, wherein the distal tip portion comprises a proximal section having a first stiffness and a distal section having a second stiffness, the second stiffness being less than the first stiffness.

3. The percutaneous circulatory assist device of claim 1 , wherein the inner molded core comprises steel.

4. The percutaneous circulatory assist device of claim 1 , wherein the inner molded core comprises a shape memory material.

5. The percutaneous circulatory assist device of claim 1 , wherein the outer layer comprises a radiopaque material.

6. The percutaneous circulatory assist device of claim 1 , wherein the distal tip portion further comprises an atraumatic spherical distal tip.

7. The percutaneous circulatory assist device according to any one of claims 1 to 6, wherein the device is usable without an auxiliary guidewire.

8. The percutaneous circulatory assist device according to any one of claims 1 to 6, wherein the device is usable with an auxiliary guidewire.

9. The housing and an impeller disposed within the housing and rotatable relative to the housing to cause blood to flow through the housing; a cannula coupled to the housing; a distal tip portion coupled to the cannula opposite the housing, the distal tip portion including an atraumatic spherical distal end; a user-shapeable metal inner molding core configured to be shaped by a user to maintain a predetermined shape of the distal tip portion; A percutaneous circulatory assist device comprising:

10. 10. The percutaneous circulatory assist device of claim 9, wherein the distal tip portion comprises a proximal section having a first stiffness and a distal section having a second stiffness, the second stiffness being less than the first stiffness.

11. The percutaneous circulatory assist device of claim 9 , wherein the distal tip portion comprises a shape memory material.

12. The percutaneous circulatory assist device of claim 9 , wherein the distal tip portion comprises steel.

13. The percutaneous circulatory assist device of claim 9 , wherein the distal tip portion comprises a radiopaque material.

14. The percutaneous circulatory assist device according to any one of claims 9 to 13, wherein the device is usable without an auxiliary guidewire.

15. The percutaneous circulatory assist device according to any one of claims 9 to 13, wherein the device is usable with an auxiliary guidewire.

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