Anti-suction blood pump inlet

Abstract

To allow a heart pump assembly to continue to function.SOLUTION: A heart pump assembly includes: an impeller blade coupled to a rotor or a drive shaft; a cannula; a distal projection coupled to a distal end of the cannula; and a blood inlet having a plurality of apertures. The apertures are radially oriented and disposed about the cannula. The apertures at least include a first ring of apertures which are proximal to the distal projection, and a second ring of apertures which are proximal of the first ring of apertures. The apertures can allow the heart pump assembly to continue to function if anatomical structures or tissues become suctioned to a portion of the heart pump.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims priority to U.S. Provisional Patent Application No. 62 / 382,471, filed on September 1, 2016, the contents of which are hereby incorporated by reference in their entirety.

Background Art

[0002] Background To pump blood from the heart into the arteries, a blood pump, such as a percutaneous intracardiac blood pump assembly, can be introduced into the heart. When the blood pump assembly operates within the heart, it draws blood from the left ventricle and discharges it into the aorta, or draws blood from the right ventricle and discharges it into the pulmonary artery. Some heart pump assemblies draw blood through an inlet opening into a cannula and discharge it from that cannula through an outlet opening into the aorta. Sometimes, the inlet opening adheres to the interior of the ventricle in which it is located or to other structures, such as the mitral valve and / or chordae tendineae. When this adhesion occurs, the flow of blood entering the pump and / or passing through the cannula is blocked or impeded, reducing the support provided to the heart.

Summary of the Invention

[0003] Summary The systems, devices, and methods described herein provide a heart pump assembly having an improved inlet opening. The inlet opening is designed to prevent or reduce the tendency for the inlet opening to adhere to the interior of the patient's heart or vascular system. In particular, the inlet opening can prevent the pump inlet from sucking in valve leaflets (e.g., the leaflets of the mitral valve) into the inlet. This can reduce the risk of occlusion of the opening and enable the pump to provide more blood pumping support to the heart. This improved opening can also reduce the risk of damage to the heart structures that can be adhered to by the pump.

[0004] The heart pump includes a plurality of inflow openings. The inflow openings can be disposed at the distal end portion of the cannula of the heart pump (for example, in the case of a pump designed to assist the left ventricle). The inflow openings can be arranged in two or more rings or rows that are offset from each other along the longitudinal axis of the pump. The use of rings or rows of multiple openings rather than a single ring of openings allows each opening to be made smaller, which can reduce the risk that a heart structure (such as a valve) will enter the inlet through the opening. Further, additional inflow openings provide redundancy such that there are additional openings through which blood can pass when one subset of the openings is blocked. The outer edge of the opening can be defined by struts coupled to the cannula. The struts can function as a shield to prevent the suction of valve leaflets onto the pump or the suction of valve leaflets into the pump.

[0005] In one aspect, a heart pump assembly includes a rotor, a motor coupled to the rotor, an impeller blade coupled to the rotor such that rotation of the rotor rotates the impeller blade and pumps blood, a cannula, a distal projection coupled to the distal end of the cannula, and a blood inlet including a plurality of openings radially oriented and disposed about the perimeter. The plurality of openings includes at least a first ring of openings proximal to the atraumatic tip and a second ring of openings proximal to the first ring of openings.

[0006] In some embodiments, the first opening in the first ring of openings has an area larger than the area of the second opening in the second ring of openings. In some embodiments, the first opening in the first ring of openings and the second opening in the second ring of openings are oval. In some embodiments, the heart pump assembly includes a third ring of openings proximal to the second ring. In some embodiments, the heart pump assembly includes a fourth ring of openings proximal to the third ring.

[0007] In some embodiments, the first opening in the first ring of openings and the third opening in the third ring of openings are aligned along an axis on the surface of the cannula that is parallel to the longitudinal axis of the cannula. In some embodiments, the second opening in the second ring of openings is aligned with the fourth opening in the fourth ring of openings along an axis on the surface of the cannula that is parallel to the longitudinal axis of the cannula.

[0008] In some embodiments, the first opening in the first ring of openings has a height measured parallel to the longitudinal axis of the cannula, and this height is greater than the height of any of the second, third, or fourth openings. In some embodiments, the height of the first opening is less than 9 mm. In some embodiments, the height of the second opening is less than 3 mm. In some embodiments, the width of the second opening is less than 4 mm. In some embodiments, the area of the first opening is less than 20 mm 2 In some embodiments, the area of the second opening is less than 12 mm 2 In some embodiments, the plurality of openings are formed on an inflow cage coupled to the cannula. In some embodiments, the inflow cage is constructed of stainless steel. In some embodiments, the plurality of openings are formed near the distal end of the cannula.

[0009] In some embodiments, some of the plurality of openings are oval. In some embodiments, some of the plurality of openings are circular. In some embodiments, some of the plurality of openings are teardrop-shaped, with the rounded edge facing the distal end of each opening and the pointed edge facing the proximal side of each opening. In some embodiments, the first opening in the first ring of openings has a smaller area than the second opening in the second ring of openings. In some embodiments, the first opening in the first ring of openings has the same area as the second opening in the second ring of openings. In some embodiments, the distal end portion of the cannula includes an inflow cage. In some embodiments, the distal edge of the first opening is formed by the base of a non-traumatic tip.

[0010] In some embodiments, each of the plurality of openings is defined by an inner edge that intersects the inside of the cannula and an outer edge that intersects the surface of the cannula. In some embodiments, the outer edge of each of the plurality of openings is rounded. In some embodiments, the outer edge of each of the plurality of openings is chamfered. In some embodiments, the heart pump assembly is sized for percutaneous insertion.

[0011] In another aspect, the heart pump assembly includes a rotor, a motor coupled to the rotor, an impeller blade coupled to the rotor such that rotation of the rotor rotates the impeller blade and pumps blood, a cannula, and a blood inlet including a plurality of openings radially oriented and disposed about the periphery. The plurality of openings includes at least a first ring of openings and a second ring of openings proximal to the first ring of openings. Of the plurality of openings, each opening of the first ring of openings has a larger area than an opening of the second ring of openings.

[0012] In some embodiments, the first opening in the first ring of openings and the second opening in the second ring of openings are oval. In some embodiments, the heart pump assembly includes a third ring of openings proximal to the second ring of openings. In some embodiments, the heart pump assembly includes a fourth ring of openings proximal to the third ring of openings. In some embodiments, the first opening in the first ring of openings and the third opening in the third ring of openings are aligned along an axis on the surface of the cannula that is parallel to the longitudinal axis of the cannula. In some embodiments, the second opening in the second ring of openings is aligned with the fourth opening in the fourth ring of openings along an axis on the surface of the cannula that is parallel to the longitudinal axis of the cannula.

[0013] In some embodiments, the first opening in the first ring of openings has a height measured parallel to the longitudinal axis of the cannula, and the height is greater than the height of any of the second opening, the third opening, or the fourth opening. In some embodiments, the height of the first opening is less than 9 mm. In some embodiments, the height of the second opening is less than 3 mm. In some embodiments, the width of the second opening is less than 4 mm. In some embodiments, the area of the first opening is less than 20 mm 2 2. In some embodiments, the plurality of openings are formed on an inflow cage coupled to the cannula. In some embodiments, the inflow cage is constructed of stainless steel. In some embodiments, the plurality of openings are formed near the end of the cannula.

[0014] In some embodiments, each of the plurality of openings is defined by an inner edge that intersects the inside of the cannula and an outer edge that intersects the surface of the cannula. In some embodiments, the outer edge of each of the plurality of openings is rounded. In some embodiments, the outer edge of each of the plurality of openings is chamfered. In some embodiments, the heart pump assembly is sized for percutaneous insertion.

[0015] In another aspect, a method of manufacturing a heart pump assembly includes coupling an impeller blade to a rotor, inserting the impeller blade into a housing, coupling a cannula to the housing, and coupling an inflow cage including a plurality of openings to the cannula. The plurality of openings are radially oriented around the inflow cage, and the plurality of openings are disposed at least in a first ring of openings and in a second ring of openings proximal to the first ring of openings.

[0016] In some embodiments, the inflow cage includes a third ring of openings proximal to the second ring of openings. In some embodiments, the inflow cage includes a fourth ring of openings proximal to the third ring of openings. In some embodiments, each of the plurality of openings includes an outer edge formed by tumbling. In some embodiments, the plurality of openings are formed near the end of the cannula. In some embodiments, the method also includes coupling a distal projection to the distal end of the inflow cage. The distal projection is distal to the plurality of openings, and the base of the distal projection forms the distal edge of the first ring of openings.

[0017] In another aspect, a method of operating a heart pump assembly includes using a motor to rotate an impeller about a rotational axis to draw blood into the cannula of the heart pump assembly through a plurality of blood inlet openings, and discharging blood from the heart pump assembly through a plurality of blood discharge openings disposed at a proximal end portion of the cannula proximal to the pump. The blood inlet openings are radially oriented around the cannula and are disposed in at least two rings at the distal end of the cannula.

[0018] After considering the present disclosure, variations and modifications will occur to those skilled in the art. The disclosed features may be embodied in any combination and sub-combination (including multiple dependent and partial combinations) with one or more of the other features described herein. For example, while various specific opening arrangements are described herein, the heart pump assembly may be configured to have any number of openings disposed in any suitable number of rings. Further, the openings may have any suitable size, shape, or arrangement. The various features described above, including any of their components, may be combined or integrated with other systems. Moreover, certain features may be omitted or not embodied. [The present invention 1001] a rotor; a motor coupled to the rotor; An impeller blade coupled to the rotor such that rotation of the rotor rotates the impeller blade and pumps blood; a cannula; a distal protrusion coupled to the distal end of the cannula; a blood inlet including a plurality of apertures radially oriented and disposed about; a heart pump assembly comprising: wherein the plurality of apertures includes at least a first ring of apertures and a second ring of apertures proximal to the first ring of apertures; the heart pump assembly. [Invention 1002] The heart pump assembly of Invention 1001, wherein a first aperture in the first ring of apertures has an area larger than an area of a second aperture in the second ring of apertures. [Invention 1003] The heart pump assembly of Invention 1002, wherein the first aperture in the first ring of apertures and the second aperture in the second ring of apertures are oval. [Invention 1004] The heart pump assembly of Invention 1003, further comprising a third ring of apertures proximal to the second ring of apertures. [Invention 1005] The heart pump assembly of Invention 1004, further comprising a fourth ring of apertures proximal to the third ring of apertures. [Invention 1006] The heart pump assembly of Invention 1005, wherein the first aperture in the first ring of apertures and the third aperture in the third ring of apertures are aligned along an axis on the surface of the cannula parallel to the longitudinal axis of the cannula. [Invention 1007] The heart pump assembly of Invention 1006, wherein the second aperture in the second ring of apertures is aligned with the fourth aperture in the fourth ring of apertures along an axis on the surface of the cannula parallel to the longitudinal axis of the cannula. [Invention 1008] The first opening in the first ring of the aperture has a height measured parallel to the longitudinal axis of the cannula, and this height is greater than the height of any of the second opening, the third opening or the fourth opening, the heart pump assembly of the present invention 1007. [The present invention 1009] The height of the first opening is less than 9 mm, the heart pump assembly of the present invention 1008. [The present invention 1010] The height of the second opening is less than 3 mm, the heart pump assembly of the present invention 1009. [The present invention 1011] The area of the first opening is 20 mm 2 less than, the heart pump assembly of the present invention 1010. [The present invention 1012] A plurality of openings are formed on the inflow cage coupled to the cannula, the heart pump assembly of the present invention 1001. [The present invention 1013] The inflow cage is composed of stainless steel, the heart pump assembly of the present invention 1012. [The present invention 1014] A plurality of openings are formed near the end of the cannula, the heart pump assembly of the present invention 1001. [The present invention 1015] Each of the plurality of openings is defined by an inner edge intersecting the inside of the cannula and an outer edge intersecting the outer surface of the cannula, and the outer edge of each of the plurality of openings is rounded, the heart pump assembly of the present invention 1001. [The present invention 1016] Each of the plurality of openings is defined by an inner edge intersecting the inside of the cannula and an outer edge intersecting the outer surface of the cannula, and the outer edge of each of the plurality of openings is chamfered, the heart pump assembly of the present invention 1001. [The present invention 1017] It is sized for percutaneous insertion, the heart pump assembly of the present invention 1001. [The present invention 1018] A rotor and; A motor coupled to the rotor and; An impeller blade coupled to the rotor such that rotation of the rotor rotates the impeller blade and pumps blood; a cannula; a blood inlet including a plurality of openings radially oriented and disposed about a periphery, the plurality of openings including at least a first ring of openings and a second ring of openings proximal to the first ring of openings; a heart pump assembly comprising; wherein the first ring of openings includes a first opening and the second ring of openings includes a second opening, the first opening having an area greater than the area of the second opening; the heart pump assembly. [Invention 1019] The heart pump assembly of Invention 1018, wherein the area of the first opening is at least twice as large as the area of the second opening. [Invention 1020] The heart pump assembly of Invention 1019, wherein the first opening has a height measured parallel to the longitudinal axis of the cannula, the height being greater than the height of the second opening measured parallel to the longitudinal axis of the cannula. [Invention 1021] The heart pump assembly of Invention 1020, wherein the height of the first opening is at least twice as large as the height of the second opening. [Invention 1022] The heart pump assembly of Invention 1021, wherein each opening of the first ring of openings has an area greater than the area of each opening of the second ring of openings. [Invention 1023] The heart pump assembly of Invention 1022, further comprising a third ring of openings proximal to the second ring. [Invention 1024] The heart pump assembly of Invention 1023, further comprising a fourth ring of openings proximal to the third ring. [Invention 1025] The heart pump assembly of Invention 1024, wherein the height of the first opening is greater than the height of a third opening of the third ring of openings or the height of a fourth opening of the fourth ring of openings. [The present invention 1026] The heart pump assembly of the present invention 1025, wherein the height of the first opening is less than 9 mm. [The present invention 1027] The heart pump assembly of the present invention 1026, wherein the height of the second opening is less than 3 mm. [The present invention 1028] The heart pump assembly of the present invention 1027, wherein the area of the first opening is less than 20 mm 2 . [The present invention 1029] The heart pump assembly of the present invention 1025, wherein the first opening in the first ring of the opening and the third opening in the third ring of the opening are aligned along an axis on the outer surface of the cannula parallel to the longitudinal axis of the cannula. [The present invention 1030] The heart pump assembly of the present invention 1029, wherein the second opening in the second ring of the opening is aligned with the fourth opening in the fourth ring of the opening along an axis on the outer surface of the cannula parallel to the longitudinal axis of the cannula. [The present invention 1031] The heart pump assembly of the present invention 1017, wherein a plurality of openings are formed on an inflow cage coupled to the cannula. [The present invention 1032] The heart pump assembly of the present invention 1031, wherein the inflow cage is made of stainless steel. [The present invention 1033] The heart pump assembly of the present invention 1017, wherein a plurality of openings are formed near the end of the cannula. [The present invention 1034] The heart pump assembly of the present invention 1017, wherein each of the plurality of openings is defined by an inner edge intersecting the inside of the cannula and an outer edge intersecting the outer surface of the cannula, and the outer edge of each of the plurality of openings is rounded. [The present invention 1035] The heart pump assembly of the present invention 1017, wherein each of the plurality of openings is defined by an inner edge intersecting the inside of the cannula and an outer edge intersecting the outer surface of the cannula, and the outer edge of each of the plurality of openings is chamfered. [The present invention 1036] The heart pump assembly of the present invention 1017, sized for percutaneous insertion. [The present invention 1037] A method of manufacturing a heart pump assembly, comprising the following steps: Coupling an impeller blade to a rotor; Inserting the impeller blade into a housing; Coupling a cannula to the housing; and Coupling an inflow cage to the cannula, wherein the inflow cage includes a plurality of openings radially oriented around the inflow cage, and the plurality of openings are disposed at least in a first ring of openings and in a second ring of openings proximal to the first ring of openings; Coupling a distal protrusion to the distal end of the inflow cage, wherein the distal protrusion is distal to the plurality of openings and a base of the distal protrusion forms a distal edge of the first ring of openings. [The present invention 1038] The method of the present invention 1037, wherein the inflow cage further includes a third ring of openings proximal to the second ring of openings. [The present invention 1039] The method of the present invention 1038, wherein the inflow cage further includes a fourth ring of openings proximal to the third ring of openings. [The present invention 1040] The method of the present invention 1039, wherein each of the plurality of openings included in the inflow cage includes an outer edge formed by tumbling.

Brief Description of the Drawings

[0019] The foregoing and other objects and advantages will become apparent by considering the following detailed description in conjunction with the accompanying drawings. In the drawings, like reference numerals refer to like parts throughout.

[0020]

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[0021] Detailed Description To provide an overall understanding of the systems, methods, and devices described herein, specific exemplary embodiments are described. The embodiments and features described herein are described with reference to openings of specific numbers, sizes, and shapes, but it will be understood that the heart pump assembly may be configured to have any suitable number of openings arranged in any number of rings without being limited to the arrangements described herein. Additionally, the openings may have any suitable size, shape, or arrangement.

[0022] The systems, devices, and methods described herein provide a heart pump assembly having an improved inflow opening. The inflow opening is designed to prevent, or reduce the tendency for, the inflow opening to suction onto the inside of a patient's heart or vascular system. In particular, the inflow opening can prevent the pump inlet from sucking in valve leaflets (e.g., the leaflets of the mitral valve) into the inlet. This can reduce the risk of occlusion of the opening and enable the pump to provide more blood pumping assistance to the heart. The improved opening can also reduce the risk of damage to the heart structures that can be suctioned onto the pump.

[0023] The heart pump includes a plurality of inflow openings. The inflow openings can be arranged at the distal end portion of the cannula of the heart pump (for example, in the case of a pump designed to assist the left ventricle). The inflow openings can be arranged in two or more rings or rows that are offset from each other along the longitudinal axis of the pump. The use of rings or rows of multiple openings instead of a single ring of openings allows each opening to be made smaller, which can reduce the risk of a heart structure (such as a valve) entering the inlet through the opening. Furthermore, additional inflow openings provide redundancy such that even if one subset of the openings is blocked, there are additional openings through which blood can pass when it enters. The outer edge of the opening can be defined by struts coupled to the cannula. The struts can function as a shield to prevent the suction of valve leaflets onto the opening or the suction of valve leaflets into the opening.

[0024] Figure 1 shows an exemplary prior art heart pump assembly 100. The heart pump assembly 100 includes a motor housing 102, a cannula assembly 108, a plurality of openings 116, a plurality of blood discharge openings 124, and a projection or atraumatic tip 112. The cannula assembly 108 includes a proximal end 111, a cannula body 109, an inflow cage 113, a distal end 110, a distal end portion 114, and a teardrop portion 142. The motor housing 102 has a proximal end 107 and a distal end 106. The plurality of openings 116 are arranged in a single ring 118 in the inflow cage 113 at the distal end portion 114 of the cannula assembly 108. The atraumatic tip 112 is coupled to the cannula assembly 108 at the distal end 110 of the cannula assembly 108 at the teardrop portion 142.

[0025] The heart pump assembly 100 draws blood through a plurality of apertures 116 and into the cannula assembly 108. The pump discharges blood through a plurality of blood discharge apertures 124 proximal to the proximal end 111 of the cannula assembly 108. The heart pump assembly 100 may be inserted percutaneously into the heart through the aorta. The plurality of apertures 116 may be disposed beyond the aortic valve in the left ventricle to draw blood from the left ventricle and discharge that blood into the aorta. The atraumatic tip 112 spaces the heart pump assembly 100 from the heart wall, but in some examples, the plurality of apertures 116 may be disposed close to the wall of the heart or various heart structures, such as the leaflets of the mitral valve. Each of the plurality of apertures 116 has a large area that can attract a heart structure, such as a valve leaflet, to the aperture 116 and further draw it into the cannula assembly 108 through the aperture 116. This can potentially block some or all of the blood flow into the cannula assembly 108. When the blood flow through the cannula assembly 108 is blocked, the assistance that the heart pump assembly 100 can provide to the heart is reduced.

[0026] Figure 2 shows a variant heart pump assembly 200 of a particular embodiment having a plurality of openings disposed into a ring. The heart pump assembly 200 includes a motor housing 202, a cannula assembly 208, a plurality of openings 216, a plurality of blood outlets 224, and a non-traumatic tip 212. The cannula assembly 208 has a proximal end 206, a cannula body 209, an inflow cage 213, a distal end 210, a distal end portion 214, and a teardrop portion 242. The non-traumatic tip 212 is coupled to the cannula assembly 208 at the distal end 210 of the cannula assembly 208 and at the teardrop portion 242. The plurality of openings 216 are disposed in the inflow cage 213 at the distal end portion 214 of the cannula assembly 208. Each of the plurality of openings 216 has a smaller area compared to the plurality of openings 116 shown in FIG. 1 and is disposed into a plurality of rings. The distal end portion 214 of the cannula assembly 208 includes a first ring of openings 218, a second ring of openings 220, and a third ring of openings 230. The inflow cage 213 including the plurality of openings 216 is approximately the same length as the inflow cage 113 of the prior art pump 100, but the plurality of openings 216 includes more smaller openings than the openings of the prior art pump 100.

[0027] The plurality of smaller openings 216 disposed in rings 218, 220, and 230 reduce the tendency for the plurality of openings 216 to suction onto the interior of the patient's heart. In particular, the plurality of smaller openings 216 prevent the heart pump assembly 200 from sucking in valve leaflets into the plurality of openings 216. This can reduce the risk of occlusion of the openings 216, thereby enabling the heart pump assembly 200 to provide more support to the heart. The openings 216 can also reduce the risk of damage to the heart structure that could otherwise be suctioned by the heart pump assembly 200. The heart pump assembly 200 can be modified in any number of ways. For example, either the embodiment of FIG. 2 and other embodiments herein can exclude the motor housing. Instead, the motor can be configured to be disposed outside of the patient's body and can be functionally coupled to the rotor via a drive shaft or cable.

[0028] Figure 3 illustrates a heart pump assembly 300 of some embodiments that includes a plurality of openings 316 in the distal end portion 314, such as the heart pump assembly 200 of FIG. 2. The heart pump assembly 300 includes a motor housing 302, an impeller blade 304, a cannula assembly 308, a plurality of openings 316, and a non-traumatic tip 312. The motor housing 302 has a distal end 306 and a proximal end 307. The impeller blade 304 is rotatable relative to the cannula assembly 308. The cannula assembly 308 includes a cannula body 309 having a proximal end 311, a distal end 310, a distal end portion 314, a teardrop portion 342, and a periphery 322. The cannula body 309 is coupled to the distal end 306 of the motor housing 302. The plurality of openings 316 are arranged into a first ring 318 and a second ring 320. The first ring 318 is disposed at the distal end of the distal end portion 314, and the second ring 320 is disposed proximal to the first ring 318. In some embodiments, the plurality of openings 316 are formed in the distal end portion 314 of the cannula assembly 308. In certain embodiments, the plurality of openings 316 are formed in an inflow cage (not shown) that is separate from but coupled to the distal end portion 314 of the cannula assembly 308. The plurality of openings are separated by a plurality of struts, such as 317a - c. The non-traumatic tip 312 is coupled to the distal end 310 of the cannula assembly 308.

[0029] The first ring 318 includes openings 318a - c. The second ring 320 includes openings 320a - c. Although the first ring 318 and the second ring 320 are shown as having three openings (318a - c and 320a - c) each, the plurality of openings 316 in the first ring 318 and the second ring 320 can also extend around the entire circumference 322 of the cannula body 309. The first ring 318 and the second ring 320 can each include any suitable number of openings. In some embodiments, the number of openings in the first ring 318 or the second ring 320 is 3, 4, 5, 6, 7, 8, 9, 10 or any other suitable number of openings. In some embodiments, the number of openings in the first ring 318 is the same as the number of openings in the second ring 320, although this is not required. In some embodiments, the number of openings in the first ring 318 is less than the number of openings in the second ring 320. In some embodiments, the number of openings in the first ring 318 is more than the number of openings in the second ring 320.

[0030] The heart pump assembly 300 draws blood into the cannula assembly 308 by the rotation of the impeller blade 304. Blood enters the cannula assembly 308 through a plurality of openings 316 in the distal end portion 314 of the cannula assembly 308. The heart pump assembly 300 can be positioned within the heart in such a way that the mitral valve leaflets are proximate to the plurality of openings 316, and in some cases, the mitral valve leaflets can be drawn to some of the plurality of openings 316, temporarily preventing blood from entering through the plurality of openings 316. Since the plurality of openings 316 are of small diameter, there is little risk that the openings 316 will allow the valve leaflets to enter the heart pump assembly 300 from the inlet. This leaves the interior of the cannula assembly 308 clear for the passage of blood. Further, the struts 317a-c between the plurality of openings 316 act as a shield to prevent the suction of valve leaflets and other tissues to the plurality of openings 316. Other parts of the anatomical structure that are drawn to some of the valve leaflets or the plurality of openings 316, or sucked into the heart pump assembly 300, reduce the area through which blood can pass when entering the cannula assembly 308, potentially reducing the flow rate of blood passing through the heart pump assembly 300. The plurality of openings 316 disposed in the distal end portion 314 of the cannula assembly 308 increase the likelihood that some of the plurality of openings 316 will not be blocked. Even if a subset of the plurality of openings 316 is blocked, blood can still enter the heart pump assembly 300 through the remaining plurality of openings 316.

[0031] The plurality of apertures 316 are shown as having an oval shape. The plurality of apertures 316 can have any suitable shape for allowing blood to enter the cannula assembly. For example, the plurality of apertures 116 can be oval, elliptical, square, teardrop, round, or any other suitable shape. The shape of the apertures 318a - c of the first ring 318 can be different from the shape of the apertures 320a - c of the second ring 320. In some embodiments, the edges of the plurality of apertures 316 are rounded or chamfered. Rounded apertures, i.e., apertures having rounded edges, can reduce the risk of hemolysis or other damage to the blood when blood enters the plurality of apertures 316. As shown, each of the apertures 318a - c of the first ring 318 has a larger area compared to each of the apertures 320a - c of the second ring 320. In some embodiments, each of the apertures 318a - c of the first ring 318 has a smaller area compared to each of the apertures 320a - c of the second ring 320. In certain embodiments, each of the apertures 318a - c of the first ring 318 has the same area as each of the apertures 320a - c of the second ring 320.

[0032] The atraumatic tip 312 coupled to the distal end 310 of the cannula assembly 308 spaces the plurality of apertures 316 away from the inner surface of the heart. This spacing prevents the plurality of apertures 316 from adhering to the heart wall, heart valve (e.g., mitral valve), or any other anatomical structure within the heart. This can reduce the risk of occlusion of the plurality of apertures 316 and can reduce or prevent damage to the heart tissue. The atraumatic tip 312 can be shaped as a flexible extension having a pigtail as shown in FIG. 3. In some embodiments, the atraumatic tip 312 is configured as a straight extension or a spherical portion. In some embodiments, the atraumatic tip 312 includes a lumen for passing a guidewire through the atraumatic tip 312.

[0033] In short, both the placement of the atraumatic tip 312 and the opening 316 serve to prevent or reduce the risk of the pump inlet being blocked by the heart wall, valve leaflets, or other anatomical structures. The atraumatic tip 312 acts as a mechanical spacer to prevent suction of the opening onto the inner surface of the heart, and the placement of the opening 316 and struts 317a - c acts as a shield to prevent tissue entry into the opening 316. Thus, the placement of the atraumatic tip 312 and the opening 316 together serve to help maintain the proper function of the heart pump assembly 301.

[0034] FIG. 4 shows a view illustrating a heart pump assembly 400, such as the heart pump assembly 200 of FIG. 2, including three rings of openings at the distal end portion 414 of a cannula assembly 408. The heart pump assembly 400 includes a motor housing 402, impeller blades 404, a catheter 428, a cannula assembly 408, a blood outlet 424, a plurality of openings 416, and an atraumatic tip 412. The cannula assembly 408 includes a cannula body 409 having a proximal end 411, a distal end 410, a distal end portion 414, a teardrop portion 442, a longitudinal axis 444, and a periphery 422. The motor housing 402 includes impeller blades 404 that are rotatable relative to the cannula assembly 408. Rotation of the impeller blades 404 generates suction through the cannula assembly 408. Blood enters the cannula assembly 408 through a plurality of openings 416 disposed at the distal end portion 414 of the cannula assembly 408. The plurality of openings 416 are disposed in the periphery 422 of the cannula body 409 in a first ring 418 having openings 418a - d, a second ring 420 having openings 420a - d, and a third ring 430 having openings 430a - d. The first ring 418 is proximal to the distal end 410 of the cannula assembly 408. The second ring 420 is proximal to the first ring 418, and the third ring 430 is proximal to the second ring 420. The plurality of openings 416 are separated by a plurality of struts 217a - c. An atraumatic tip 412 is attached to the distal end 410 of the teardrop portion 442 of the cannula assembly 408.

[0035] Each of the plurality of openings 416 has a height, a width, and an area. The plurality of openings 416 can have various sizes. The first ring 418 can have an opening 418d that has a larger area than the opening 420d of the second ring or the opening 430d of the third ring 430. The area of the opening 418d of the first ring 418 can be less than 20 mm 2 . In some embodiments, the area of the opening 418d of the first ring 218 is 0.5 mm 2 , 1 mm 2 , 5 mm 2 , 10 mm 2 , 15 mm 2 , 18 mm 2 , 20 mm 2 , 23 mm 2 , 25 mm 2 or any other suitable area. The area of the opening 420d of the second ring 420 can be less than 12 mm 2 . In some embodiments, the area of the opening 420d of the second ring 420 is 0.25 mm 2 , 0.5 mm 2 , 1 mm 2 , 2 mm 2 , 5 mm 2 , 10 mm 2 , 12 mm 2Or it can be any other suitable area. The area of the opening 430d of the third ring 430 can be the same as the area of the opening 420d of the second ring. The height of the opening 418b of the first ring 418 measured along an axis parallel to the longitudinal axis 444 of the cannula assembly 408 can be less than 9 mm. In some embodiments, the height of the opening 418b of the first ring 418 is 0.5 mm, 1 mm, 3 mm, 5 mm, 6 mm, 9 mm, 10 mm, 12 mm, 15 mm, or any other suitable height. The height of the opening 420b of the second ring 420 measured along an axis parallel to the longitudinal axis 444 of the cannula assembly 408 can be less than 3 mm. In some embodiments, the height of the opening 420b of the second ring 420 is 0.25 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 5 mm, 6 mm, or any other suitable height. The width of the opening 420b of the second ring 420 measured transversely to the longitudinal axis 444 can be less than 4 mm. In some embodiments, the width of the opening 420b of the second ring 420 is 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 5 mm, 6 mm, 8 mm, or any other suitable width. In some embodiments, the height and width of the opening 430b are the same as the height and width of the opening 420b.

[0036] The plurality of openings 416 prevent the heart pump assembly 400 from failing due to the suction of the valve leaflets into a portion of the plurality of openings 416. The plurality of openings 416 disposed in the rings 418, 420, and 430 reduce the tendency of the plurality of openings 416 to suck the heart structure into the inlet of the heart pump assembly 400. The plurality of openings 416, together with the struts 417a-c, prevent the heart pump assembly 400 from sucking the valve leaflets into the plurality of openings 416, thereby reducing the risk of the openings 416 being blocked and enabling the heart pump assembly 400 to continue to provide support to the heart. Further, the plurality of openings 416 provide a redundant inlet for blood to enter even if one or more of the plurality of openings 416 are blocked by valve leaflets or other tissue.

[0037] In some embodiments, a large portion of the blood entering the cannula assembly 408 enters through the most proximal opening of the plurality of openings 416, e.g., through the openings 430a-c of the third ring 430. When one or more of the plurality of openings 416 in the third ring 430 are blocked, a greater amount of blood can enter through the plurality of openings 416 in the second ring 420 or the first ring 418. Additional openings provide additional inlets through which blood can pass as it enters the heart pump assembly. In addition, struts 417a-c defining the plurality of openings 416 act as a shield to prevent tissue from adhering to or being drawn into the heart pump assembly 400.

[0038] FIG. 4 shows a heart pump assembly 400 having a plurality of openings disposed in three rings, but in some embodiments, there may be additional rings of openings. For example, FIG. 5 shows a perspective view of the distal end portion 514 of a cannula assembly having four rings of openings, and FIG. 6 shows a front view of the distal end portion 514 of the cannula assembly of FIG. 5. The distal end portion 514 includes a distal end 510, a non-traumatic tip connector 548, a teardrop portion 542, a longitudinal axis 544, and a plurality of openings 516 disposed in a first ring 518, a second ring 520, a third ring 530, and a fourth ring 540. The plurality of openings 516 in the first ring 518 include openings 518a-e radially oriented around the distal end portion 514. The second ring 520 of openings 520a-e, the third ring 530 of openings 530a-e, and the fourth ring 540 of openings 540a-e are radially oriented around the distal end portion 514.

[0039] The first ring 518 of the openings 518a - e has the greatest height among the four rings of the openings. The first ring 518 of the openings 518a - e has a distal edge 551 of each opening defined by a portion 552 of the teardrop portion 542. The teardrop portion 542 can be manufactured separately from the rest of the cannula assembly in which the remainder of the plurality of openings 516 are disposed and can be joined to a cannula assembly (not shown) as part of the manufacturing process. As a result, the first ring 518 of the openings 518a - e can be formed during the manufacturing process in the cannula assembly (or in an inflow cage, not shown) as having only three sides initially defined and a fourth distal side being open. Then, when joined to the cannula assembly, the fourth distal edge 551 of each opening 518a - e is defined by a portion 552 of the teardrop portion 542. The proximal edges 553 of the openings 518a - e are rounded, giving the openings 518a - e an oval shape.

[0040] The openings 520a - e of the second ring 520 are offset in the rotational direction from the openings 518a - e of the first ring, and a line 555 drawn through the center of the opening 518b, which is parallel to the longitudinal axis 544 of the distal end portion 514, does not pass through the center of any of the openings 520a - e of the second ring 520. In some embodiments, the line 555 may pass through a portion of one of the openings 520a - e, but not through the center of the openings 520a - e. The openings 530a - e are aligned with the openings 518a - e in the rotational direction, and the line 555 passes through the center of one of the openings 518a - e and the center of one of the openings 530a - e. In particular, the line 555 passes through the center of the opening 518b and the center of the opening 530b. Since the openings 540a - e are offset in the rotational direction from the openings 518a - e and the openings 530a - e, the line 555 does not pass through the center of any of the openings 540a - e of the fourth ring 540. The openings 520a - e of the second ring 520 are aligned with the openings 540a - e of the fourth ring 540 in the rotational direction, and a line 557 parallel to the longitudinal axis 544 of the distal end portion 514 passes through the centers of the openings 520b and 540b. In some embodiments, the different rings of openings may be aligned or offset in the rotational direction. For example, in some embodiments, the openings 518a - e of the first ring 518 and the openings 520a - e of the second ring 520 may be aligned with each other in the rotational direction, but the openings 530a - e of the third ring 530 and the openings 540a - e of the fourth ring 540 are not aligned with the first ring 518 and the second ring 520 in the rotational direction. In some embodiments, the openings 518a - e and the openings 530a - e are aligned, and the openings 520a - e and the openings 540a - e are offset in the rotational direction from the first ring 518 and the third ring 530. In some embodiments, the second ring 520 and the fourth ring 540 are offset by different amounts in the rotational direction from the first ring 518, and a line 557 drawn through the opening 520b of the second ring 520 does not pass through the center of any of the openings 540a - e of the fourth ring 540.

[0041] Each of the openings 518a - e, 520a - e, 530a - e, and 540a - e of the plurality of openings 516 has a corresponding height measured parallel to the vertical axis 544, a width measured transverse to the vertical axis 544, and an area. For example, opening 518a has a height 538 and a width 541. Opening 518a also has an area 532 through which blood can pass. The opening 520b of the second ring 520 has a height 554, a width 556, and an area 534. The opening 530b of the third ring 530 has a height 558, a width 560, and an area 536. The opening 540b of the fourth ring 540 has a height 562, a width 564, and an area 566. In some embodiments, the measured values, including one or more of the height, width, and area of the openings in a particular ring, are common to all the openings in that ring, although this is not required. In some embodiments, the measured values, including one or more of the height, width, and area, differ among the openings in a particular ring. In some embodiments, the openings 520a - e in the second ring 520, the openings 530a - e in the third ring 530, and the openings 540a - e in the fourth ring 540 have the same measured values, including one or more of the height, width, and area. In some embodiments, one or more of the height, width, or area of the openings differ among the openings 520a - e in the second ring 520, the openings 530a - e in the third ring 530, and the openings 540a - e in the fourth ring 540. In some embodiments, the combined area of the openings 518a - e in the first ring 518, the openings 520a - e in the second ring 520, the openings 530a - e in the third ring 530, and the openings 540a - e in the fourth ring 540 is equal to or greater than the cross-sectional area of the cannula assembly.

[0042] Despite the openings 518a - e in the first ring 518 having a larger area 532 than the openings 520a - e in the second ring 520, the openings 530a - e in the third ring 530, and the openings 540a - e in the fourth ring 540, blood mainly flows through the most proximal opening of the plurality of openings 516 due to a smaller pressure drop at the most proximal opening of the plurality of openings 516. Even if all or a portion of the openings 540a - e of the fourth ring 540 are blocked by valve leaflets, blood can still flow through the remaining openings. The smaller areas of the openings 520a - e in the second ring 520, the openings 530a - e in the third ring 530, and the openings 540a - e in the fourth ring 540, as well as the struts 517a - c between the inlets, reduce the likelihood that additional inlets will be blocked by valve leaflets.

[0043] FIG. 7 shows a front view of a distal end portion 714 of a cannula assembly 708 having a plurality of apertures 716 disposed in two rings offset in the rotational direction. The cannula assembly 708 includes a cannula body 709, a distal end portion 714, a distal end 710, a non-traumatic tip 712, a teardrop portion 742, a longitudinal axis 744, a plurality of struts 717a-c, and a plurality of apertures 716. The plurality of apertures 716 are disposed in a first ring 718 of apertures 718a-b and a second ring 720 of apertures 720a-b. The plurality of apertures 716 in the cannula assembly 708 are arranged such that the first ring 718 of apertures 718a-b is offset in the rotational direction from the second ring 720 of apertures 720a-b. A line 755 drawn parallel to the longitudinal axis 744 of the cannula assembly 708 and passing through the center of aperture 718a of the first ring 718 does not pass through the center of any of the apertures 720a-b of the second ring 720. Instead, the line 755 passes through a strut 717b that divides the apertures 720a and 720b of the second ring 720. The apertures offset in the rotational direction can prevent the valve leaflets from completely occluding two or more of the apertures. For example, if a valve leaflet is drawn to the cannula assembly 708 and covers aperture 718a of the first ring 718, the rotational direction offset of the second ring 720 of apertures 720a-b can prevent the valve leaflet from occluding all of the further apertures 720a or 720b of the second ring 720.

[0044] Figures 5, 6, and 7 show the distal end portions (e.g., distal end portion 514 of FIG. 5 or distal end portion 714 of FIG. 7) of a cannula assembly having a plurality of apertures offset in the rotational direction (e.g., the plurality of apertures 516 of FIG. 5 or the plurality of apertures 716 of FIG. 7), while FIG. 8 shows a perspective view of the distal end portion 814 of a cannula assembly 808 in which the plurality of apertures 816 are aligned with each other in the rotational direction. FIG. 9 shows an alternative perspective view of the distal end portion 914 having a plurality of apertures 916 aligned in the rotational direction. The cannula assembly 908 includes a cannula body 909, a distal end portion 914, a distal end 910, a non-traumatic tip 912, a teardrop portion 942, a non-traumatic tip connector 948, a longitudinal axis 944, and a plurality of apertures 916. The plurality of apertures 916 are disposed in a first ring 918 of apertures 918a - d and a second ring 920 of apertures 920a - d. The plurality of apertures 916 in the cannula assembly 908 are arranged such that the first ring 918 of apertures 918a - d is aligned with the second ring 920 of apertures 920a - d in the rotational direction. A line 955 drawn parallel to the longitudinal axis 944 of the cannula assembly 908 and passing through the center of aperture 918b of the first ring 918 also passes through the center of aperture 920b of the second ring 920. The apertures 918a - d and apertures 920a - d are taller than they are wide, and the area of each aperture 918a - d and 920a - d is shown as being defined by an ellipse through which blood can pass when it enters the cannula assembly 908. Apertures aligned in the rotational direction can be machined into the cannula assembly 908 more easily than offset apertures.

[0045] FIG. 10 shows a front view of the distal end portion 1014 of a cannula assembly 1008 having a plurality of round openings 1016 offset in the rotational direction from each other. The cannula assembly 1008 of FIG. 10 includes a distal end 1010, a distal end portion 1014, a non-traumatic tip connector 1048, a teardrop portion 1042, a longitudinal axis 1044, a non-traumatic tip 1012, and a plurality of openings 1016. The plurality of openings 1016 are arranged in a first ring 1018 of openings 1018a-c, a second ring 1020 of openings 1020a-b, a third ring 1030 of openings 1030a-c, and a fourth ring 1040 of openings 1040a-b. The openings 1018a-c of the first ring 1018 are oval. In particular, the first ring 1018 of openings 1018a-c has a proximal edge 1053 that is rounded and a distal edge 1051 that is defined by a portion of the teardrop portion 1042. The openings 1020a-b in the second ring 1020, the openings 1030a-c in the third ring 1030, and the openings 1040a-b in the fourth ring 1040 are circular. The openings 1018a-c in the first ring 1018 and the openings 1030a-c in the third ring 1030 are rotationally aligned such that a line 1055 passing through the center of opening 1018b passes through the center of opening 1030b. The openings 1020a-b in the second ring 1020 and the openings 1040a-b in the fourth ring 1040 are offset in the rotational direction from the openings 1018a-c and the openings 1030a-c, but are rotationally aligned with each other, and a line 1057 passing through the center of opening 1020, which is parallel to the longitudinal axis 1044 of the cannula 1008, passes through the center of opening 1040a. The plurality of openings 1016 having a circular shape and arranged in a ring around the cannula assembly 1008 such that the openings of each ring are offset in the rotational direction from the openings of the ring immediately above or below it can reduce the possibility that the valve leaflets block the plurality of openings.

[0046] FIG. 10 shows the distal end portion 1014 of a cannula assembly 1008 having a first ring of apertures and three additional rings of round apertures, while FIG. 11 shows the distal end portion 1114 of a cannula assembly having a first ring of apertures and only two additional rings of round apertures. The distal end portion 1114 of FIG. 11 includes a distal end 1110, a non-traumatic tip connector 1148, a teardrop portion 1142, a longitudinal axis 1144, and a plurality of apertures 1116. The plurality of apertures 1116 are disposed in a first ring 1118 of apertures 1118a-d, a second ring 1120 of apertures 1120a-c, and a third ring 1130 of apertures 1130a-c. The apertures 1118a-e of the first ring 1118 are oval, with the distal edge 1151 defined by a portion 1152 of the teardrop portion 1142. The proximal edge 1153 of the apertures 1118a-e is rounded. The apertures 1120a-c in the second ring 1120 and the apertures 1130a-c in the third ring 1130 are circular. Similar to the plurality of apertures 1116 of FIG. 10, the rings of the plurality of apertures 1116 are offset in the rotational direction. For example, the apertures 1118a-e in the first ring 1118 and the apertures 1030a-c in the third ring 1130 are rotationally aligned such that a line 1155 passing through the center of aperture 1118b passes through the center of aperture 1130a.

[0047] Figures 10 and 11 show distal end portions having a plurality of circular and oval openings, while Figure 12 shows a front view of a distal end portion 1214 of a cannula assembly in which a first ring 1218 has a teardrop-shaped opening 1218a and a plurality of openings 1216 in which the openings in further rings are circular. The distal end portion 1214 includes a distal end 1210, a non-traumatic tip connector 1248, a teardrop portion 1242, a longitudinal axis 1244, and a plurality of openings 1216. The plurality of openings 1216 are disposed in a first ring 1218 of openings 1218a, a second ring 1220 of openings 1220a-b, and a third ring 1230 of openings 1230a. Only one opening 1218a and one opening 1230a are visible in Figure 12, but there may be a plurality of openings in each of the rings 1218, 1220, and 1230 radially disposed around the distal end 1214 of the cannula assembly. The opening 1218c in the first ring 1218 is teardrop-shaped, and the distal edge 1251 defined by a portion 1252 of the teardrop portion 1242 of the non-traumatic tip connector 1248 is rounded, and the proximal edge 1253 is pointed in the direction of blood flow passing through the cannula. The second ring 1220 of openings 1220a-b and the third ring 1230 of openings 1230a are circular. In some embodiments, one or both of the second ring 1220 of openings 1220a-b and the third ring 1230 of openings 1230a are rotationally aligned with the first ring 1218 of openings 1218a.

[0048] FIG. 12 shows a first ring 1218 of a teardrop-shaped opening, while the openings of the other rings are circular. However, in some embodiments, all of the openings are teardrop-shaped. For example, FIG. 13 shows a front view of a distal end portion 1314 having a teardrop-shaped opening in a first ring 1318 and a plurality of teardrop-shaped openings disposed in a second ring 1320 and a third ring 1330. The distal end portion 1314 includes a distal end 1310, a non-traumatic tip connector 1348, a teardrop portion 1342, a longitudinal axis 1344, and a plurality of openings 1316 disposed in a first ring 1318 of an opening 1318a, a second ring 1320 of openings 1320a-b, and a third ring 1330 of an opening 1330a. Similar to FIG. 11, in FIG. 12, only one opening 1218a and 1230a can be seen in the first ring 1218 and the third ring 1230, but each ring may include a plurality of openings disposed around the distal end portion 1214 of the cannula assembly. Similar to the first ring 1218 of the opening 1218a in FIG. 12, the opening 1318a in the first ring is teardrop-shaped and has a rounded distal edge 1351 defined by the teardrop portion 1342 of the non-traumatic tip connector 1348 and a proximal edge 1353 that tapers along the longitudinal axis 1344. The openings 1320a-b in the second ring 1320 and the openings 1330a-c in the third ring 1330 are also teardrop-shaped, each opening having a rounded distal end and a pointed proximal end. An opening that tapers from a larger opening at the distal end to a pointed opening at the proximal end can facilitate blood flow through the opening and suppress its stagnation when blood flows into the plurality of openings 1316.

[0049] Changes in the number and size of the openings in the distal end portion can change the blood flow distribution to the cannula. FIGS. 14-23 show further arrangements of the openings in the distal end portion of the cannula. All of the arrangements in FIGS. 14-23 show a plurality of openings disposed in a similar portion of the distal end portion of the cannula, but the openings differ in shape, position, and relative size. FIG. 14 shows a front view of the distal end portion 1414 of a particular embodiment of a heart pump assembly having a plurality of openings 1416 arranged in three rings of openings. The distal end portion 1414 includes a distal end 1410, a non-traumatic tip connector 1448, a teardrop portion 1442, a longitudinal axis 1444, a plurality of openings 1416, a first circumferential strut 1463, and a second circumferential strut 1465. The circumferential struts 1463 and 1465 extend around the distal end portion 1414 and divide the plurality of openings 1416 into rings of openings. The plurality of openings 1416 are disposed in a first ring 1418 of openings 1418a-c, a second ring 1420 of openings 1420a-c, and a third ring 1430 of openings 1430a-c. The first circumferential strut 1463 divides the first ring 1418 from the second ring 1420. The second circumferential strut 1465 divides the second ring 1420 from the third ring 1430. The openings 1418a-c are defined in part by the teardrop portion 1442 on one side. The openings 1418a-c of the first ring 1418 are oval and each have a height greater than the width. The openings 1420a-c of the second ring 1420 and the openings 1430a-c of the third ring 1430 are oval and each have a height greater than the width. Additionally, the openings 1420a-c of the second ring 1420 and the openings 1430a-c of the third ring 1430 have a rounded proximal edge and a straight distal edge.

[0050] FIG. 15 shows a front view of the distal end portion 1514 of a cannula assembly of a particular embodiment. The distal end portion 1514 includes a distal end 1510, a non-traumatic tip connector 1548, a teardrop portion 1542, a longitudinal axis 1544, a plurality of apertures 1516, a first circumferential strut 1563, and a second circumferential strut 1565. The circumferential struts 1563 and 1565 extend around the distal end portion 1514 and divide the plurality of apertures 1516 into rings of apertures. The plurality of apertures 1516 are arranged into three rings of apertures, namely a first ring 1518 of apertures 1518a-c, a second ring 1520 of apertures 1520a-c, and a third ring 1530 of apertures 1530a-c. The first circumferential strut 1563 divides the first ring 1518 from the second ring 1520. The second circumferential strut 1565 divides the second ring 1520 from the third ring 1530. The apertures 1518a-c of the first ring 1518 have a height that is smaller along the longitudinal axis 1544 than the apertures 1418a-c of the first ring 1418 of FIG. 14, with one side defined by the teardrop portion 1542. The size and shape of the apertures 1520a-c and the apertures 1530a-c are the same as in FIG. 14. Additionally, the first circumferential strut 1563 between the first ring 1518 and the second ring 1520 has a greater height in the direction of the longitudinal axis 1544 than the first circumferential strut 1463 that divides the first ring 1418 and the second ring 1420 of FIG. 14. This can provide an additional area that does not cause suction and can prevent the suction of valve leaflets to the cannula assembly according to a particular embodiment.

[0051] FIG. 16 shows a front view of the distal end portion 1614 of a particular embodiment. The distal end portion 1614 includes a distal end 1610, a non-traumatic tip connector 1648, a teardrop portion 1642, a longitudinal axis 1644, a plurality of apertures 1616, a first circumferential strut 1663, and a second circumferential strut 1665. The circumferential struts 1663 and 1665 extend around the distal end portion 1614 and divide the plurality of apertures 1616 into rings of apertures. The plurality of apertures 1616 are arranged into three rings of apertures, namely a first ring 1618 of apertures 1618a-c, a second ring 1620 of apertures 1620a-c, and a third ring 1630 of apertures 1630a-c. The first circumferential strut 1663 divides the first ring 1618 from the second ring 1620. The second circumferential strut 1665 divides the second ring 1620 from the third ring 1630. The apertures 1618a-c of the first ring 1618 have one side defined by the teardrop portion 1642. The height of the apertures 1618a-c of the first ring 1618 is less than the height of the apertures 1618a-c of the first ring 1518 of FIG. 15. The size and shape of the apertures 1620a-c and 1630a-c are the same as in FIGS. 14 and 15, but the height of the apertures 1618a-c of the first ring 1618 is less than the height of the corresponding apertures in FIGS. 14 and 15. Additionally, the first circumferential strut 1663, which divides the first ring 1618 from the second ring 1620 in the arrangement of FIG. 16, has a greater height along the longitudinal axis 1644 than the corresponding circumferential struts 1463 and 1563 in FIGS. 14 or 15.

[0052] FIG. 17 shows a front view of the distal end portion 1714 of a cannula assembly of a particular embodiment having a plurality of apertures 1716 disposed into two rings of apertures. The distal end portion 1714 includes a distal end 1710, a non-traumatic tip connector 1748, a teardrop portion 1742, a longitudinal axis 1744, a plurality of apertures 1716, and a circumferential strut 1763. The circumferential strut 1763 extends around the distal end portion 1714 and divides the plurality of apertures 1716 into rings of apertures. The plurality of apertures 1716 are disposed in a first ring 1718 of apertures 1718a - c and a second ring 1720 of apertures 1720a - c. The circumferential strut 1763 divides the first ring 1718 from the second ring 1720. The shape of the apertures 1718a - c of the first ring 1718 can be oval with a distal edge 1751 defined by the teardrop portion 1742, the same as FIGS. 14 - 16. The size and shape of the apertures 1720a - c of the second ring 1720 can be the same as FIGS. 14 - 16. The apertures 1718a - c of the first ring 1718 and the apertures 1720a - c of the second ring 1720 are shown offset from each other. However, in some embodiments, the apertures 1718a - c of the first ring 1718 are rotationally aligned with the apertures 1720a - c of the second ring 1720.

[0053] FIG. 18 shows a front view of the distal end portion 1814 of a cannula assembly of a particular embodiment having a plurality of apertures 1816 arranged into two rings of apertures. The distal end portion 1814 of the cannula 1808 includes a distal end 1810, a non-traumatic tip connector 1848, a teardrop portion 1842, a plurality of apertures 1816, and a circumferential strut 1863. The circumferential strut 1863 extends around the distal end portion 1814 and divides the plurality of apertures 1816 into rings of apertures. The plurality of apertures 1816 are arranged into a first ring 1818 having apertures 1818a-c and a second ring 1820 having apertures 1820a-c. The circumferential strut 1863 divides the first ring 1818 from the second ring 1820. The apertures 1818a-c of the first ring 1818 have a height that is defined on one side by the teardrop portion 1842 and is smaller than the height of the apertures 1718a-c of the distal end portion of FIG. 17. The area through which blood can pass when entering the cannula assembly 1808 can be decreased in FIG. 18 compared to FIG. 17. However, the circumferential strut 1863 1820 of FIG. 18 is larger than the circumferential strut 1763 of FIG. 17. This can increase the area where suction does not occur and reduce the likelihood of drawing valve leaflets or other tissue into the cannula assembly.

[0054] Figures 19-23 illustrate arrangements of various embodiments where the distal end portion includes a plurality of openings disposed in four rings. For example, FIG. 19 shows a front view of the distal end portion 1914 of a cannula assembly. The distal end portion 1914 includes a distal end 1910, a non-traumatic tip connector 1948, a teardrop portion 1942, a longitudinal axis 1944, a plurality of openings 1916, a first circumferential strut 1963, a second circumferential strut 1965, and a third circumferential strut 1967. The circumferential struts 1963, 1965, and 1967 extend around the distal end portion 1914 and divide the plurality of openings 1916 into rings of openings. The plurality of openings 1916 are disposed in a first ring 1918 of openings 1918a-c, a second ring 1920 of openings 1920a-c, a third ring 1930 of openings 1930a-c, and a fourth ring 1940 of openings 1940a-c. The first circumferential strut 1963 divides the first ring 1918 from the second ring 1920. The second circumferential strut 1965 divides the second ring 1920 from the third ring 1930. The third circumferential strut 1967 divides the third ring 1930 from the fourth ring 1940. The openings 1918a-c have one side defined by the teardrop portion 1942. The heights of the openings 1918a-c of the first ring 1918, the openings 1920a-c of the second ring 1920, the openings 1930a-c of the third ring 1930, and the openings 1940a-c of the fourth ring 1940 are similar. The first circumferential strut 1963 has a height similar to that of the second circumferential strut 1965 and also similar to the height of the third circumferential strut 1967. The areas of the openings 1918a-c of the first ring 1918 are similar to the areas of the openings 1920a-c of the second ring 1920, the openings 1930a-c of the third ring 1930, and the openings 1940a-c of the fourth ring 1940. The openings in the second ring 1920, the third ring 1930, and the fourth ring 1940 are shown in alignment with the openings 1918a-c of the first ring, although in some embodiments, the openings can be offset in the rotational direction.

[0055] Figure 20 shows a front view of the distal end portion 2014 of a cannula assembly 2008 of a particular embodiment having a plurality of apertures 2016 where each ring of the apertures has a different size and shape. The distal end portion 2014 includes a distal end 2010, a non-traumatic tip connector 2048, a teardrop portion 2042, a longitudinal axis 2044, and a plurality of apertures 2016. The plurality of apertures 2016 are disposed in a first ring 2018 of apertures 2018a - c, a second ring 2020 of apertures 2020a - b, a third ring 2030 of apertures 2030a - b, and a fourth ring 2040 of apertures 2040a - b. The apertures 2018a - c have one side defined by the teardrop portion 2042. The apertures 2018a - c of the first ring 2018 have the greatest height of the plurality of apertures 2016. The apertures 2020a - b of the second ring 2020 have the next greatest height. The apertures 2030a - b of the third ring 2030 have the next greatest height after that. The apertures 2040a - b of the fourth ring 2040 have the least height of the plurality of apertures 2016. The plurality of apertures 2016 are shown as having a rounded shape, but the plurality of apertures 2016 can have any suitable shape while maintaining the relationship between the heights. In some embodiments, the height of the apertures 2018a - c of the first ring 2018 is less than six times the height of the apertures 2020a - b of the second ring 2020. In some embodiments, the height of the apertures 2020a - b of the second ring 2020 is less than three times the height of the apertures 2030a - b of the third ring 2030. In some embodiments, the height of the apertures 2030a - b of the third ring 2030 is less than five times the height of the apertures 2040a - b of the fourth ring 2040.

[0056] In FIGS. 21-22, the openings of the first ring have the same oval shape and the same size, and the openings of the second, third, and fourth rings have the same size and shape. In FIG. 21, the distal end portion 2114 includes a distal end 2110, a non-traumatic tip connector 2148, a teardrop portion 2142, a longitudinal axis 2144, and a plurality of openings 2116. The plurality of openings 2116 are disposed in a first ring 2118 of openings 2118a-c, a second ring 2120 of openings 2120a-c, a third ring 2130 of openings 2130a-c, and a fourth ring 2140 of openings 2140a-c. The openings 2118a-c of the first ring 2118 are oval. In particular, the first ring 2118 of openings 2118a-c has a proximal edge 2153 that is rounded and a distal edge 2151 that is defined by a portion 2152 of the teardrop portion 2142. The openings 2120a-c in the second ring 2120 are the same shape and size as the openings 2130a-c in the third ring 2130 and the openings 2140a-c in the fourth ring 2140. The plurality of openings 2116 in the second ring 2120, the third ring 2130, and the fourth ring 2140 are oval and each has a width greater than the height measured along a line parallel to the longitudinal axis 2144. The plurality of openings 2116 in the second ring 2120, the third ring 2130, and the fourth ring 2140 have proximal edges 2169a-c that are rounded and the center of the proximal edges 2153 and 2169a-c is the most proximal point of each opening. Each opening has an inner edge 2171a-d. The inner edges 2171a-d of each of the plurality of openings 2116 are chamfered. The chamfer can be at an angle of 45° or less with respect to a line perpendicular to the surface of the cannula assembly 108. In some embodiments, the chamfered inner edges 2171a-d include a chamfer of 10°, 20°, 30°, 40°, 50°, >50°, or any other suitable angle. The use of the chamfered inner edges 2171a-d can reduce hemolysis when blood enters the cannula assembly 2108. The chamfered inner edges 2171a-d are shown here in an arrangement having four rings of openings, but the chamfered inner edges can be used in any of the arrangements shown herein.In FIG. 22, similar to FIG. 21, the distal end portion 2214 includes a distal end 2210, a non-traumatic tip connector 2248, a teardrop portion 2242, a longitudinal axis 2244, and a plurality of apertures 2216 disposed in a first ring 2218 of apertures 2218a-c, a second ring 2220 of apertures 2220a-c, a third ring 2230 of apertures 2230a-c, and a fourth ring 2240 of apertures 2240a-c. Each of the plurality of apertures 2216 has a rounded inner edge 2271a-d. In some embodiments, the rounded inner edges 2271a-d include a radius of curvature in the range of 40 microns to 105 microns. In some embodiments, only the outward portions of the inner edges 2271a-d are rounded. In some embodiments, the rounding of the inner edges 2271a-d is achieved by polishing. In some embodiments, the rounding of the inner edges 2271a-d is achieved by tumbling. The rounded edges can reduce hemolysis when blood enters the cannula assembly 2208 through the plurality of apertures 2216. The rounded inner edges 2271a-d are shown here in an arrangement having four rings of apertures, but the rounded inner edges can be used in any of the arrangements shown herein.

[0057] FIG. 23 shows a front view of the distal end portion 2314 of a cannula assembly. The distal end portion 2314 includes a distal end 2310, a non-traumatic tip connector 2348, a teardrop portion 2342, a longitudinal axis 2344, and a plurality of apertures 2316. The plurality of apertures are disposed in a first ring 2318 of apertures 2318a-c, a second ring 2320 of apertures 2320a-c, a third ring 2330 of apertures 2330a-c, and a fourth ring 2340 of apertures 2340a-c. The apertures 2318a-c of the first ring 2318 have an oval shape in which the distal edge 2351 has an oval defined by the teardrop portion 2342. The plurality of apertures 2320a-c, 2330a-c, and 2340a-c of the second ring 2320, third ring 2330, and fourth ring 2340, respectively, are oval-shaped with a width greater than the height, and all of the plurality of apertures of the second ring 2320, third ring 2330, and fourth ring 2340 are the same size.

[0058] FIG. 24 shows a plot 2400 showing the predicted flow rate of fluid passing through a plurality of openings in the arrangement of FIG. 23. Plot 2400 includes a cutaway view of the distal end portion 2414 of the cannula assembly, a second opening 2420, a fourth opening 2440, and a box 2441 indicating a high flow region. The plot shows the predicted flow rate of fluid passing through two openings of the heart pump shown in cross-section. The heart pump has first, second, third, and fourth rings of openings, but in the illustrated embodiment, the first ring 2418 and the third ring 2430 are offset in the rotational direction, so only the openings of the second ring 2420 and the fourth ring 2440 are visible. In the plot, regions of higher velocity are indicated by longer lines and regions of lower flow rate are indicated by fewer lines. The magnitude of the fluid flow velocity ranges from 1.28×e -05 m / s (about 0 m / s) to 6.08 m / s. The maximum volumetric flow rate (highlighted by box 2441) occurs at the most proximal opening, in this case the opening 2440a of the fourth ring 2440. The high inflow of fluid into the cannula assembly 2408 at this point is due to the relatively high pressure gradient at this opening. Blood is drawn from outside the cannula assembly 2408 through the opening into the cannula assembly 2408, where it flows to a downstream opening (not shown).

[0059] Figure 25 shows a percutaneous heart pump assembly 2500 having a plurality of apertures 2516 in a distal end portion 2514 inserted into a patient's blood vessel 2501. In particular, the heart pump assembly 2500 is introduced through the patient's blood vessel 2501 into the heart 2503. The heart 2503 includes the aorta 2568, aortic arch 2577, aortic valve 2570, left ventricle 2572, left atrium 2576 and mitral valve 2574, as well as other structures. The heart pump assembly 2501 includes a catheter 2528, a motor housing 2502, a cannula assembly 2508, a cannula body 2509, a distal end portion 2514, a proximal end 2506, a distal end 2510, a non-traumatic tip 2512, a plurality of apertures 2516 and a plurality of blood outlets 2524. The motor housing 2502 of the heart pump assembly 2500 is connected to a motor (not shown). The motor is internal to the motor housing 2502 and is integral with the motor housing 2502. In other embodiments, the motor is external to the body and is connected to the pump via a drive shaft (not shown) within the catheter 2528, and in such an example, the assembly 2508 may not include the motor housing 2502. The cannula assembly 2508 is connected to the distal end of the motor housing 2502. The distal end portion 2514 of the cannula assembly 2508 includes a plurality of apertures 2516 through which blood can pass when it enters the cannula assembly 2508. The plurality of apertures 2516 are arranged into at least a first ring 2518 and a second ring 2520 of apertures that are radially oriented and disposed around the cannula assembly 2508. Although two rings of apertures are shown here, any arrangement of apertures described herein may be used. In some embodiments, the plurality of apertures 2516 are arranged into three, four or more rings of apertures. The non-traumatic tip 2512 is coupled to the distal end 2510 of the cannula assembly 2508, which is distal to the plurality of apertures 2516. Blood is drawn into the cannula assembly 2508 from the plurality of apertures 2516 along path 2578. The blood passes through the cannula assembly 2508 and exits along path 2580 from a plurality of blood outlets 2524 that are proximal to the motor housing 2502.

[0060] The heart pump assembly 2500 can be introduced percutaneously through the vasculature during a cardiac procedure. Specifically, the heart pump assembly 2500 can be percutaneously inserted via a catheterization procedure, passed through the femoral artery, into the ascending aorta 2568, through the aortic valve 2570, and into the left ventricle 2572. The heart pump assembly 2500 can be positioned within the patient's heart 2503 such that it is inserted over the aortic arch 2577. The plurality of blood outlets 2524 can be positioned in the aorta 2568, above the aortic valve 2570. The cannula assembly 2508 is positioned to pass through the aortic valve 2570 such that the plurality of apertures 2516 through which blood passes are positioned within the left ventricle 2572 of the heart 2503. The atraumatic tip 2512 spaces the cannula assembly 2508 away from the wall of the heart 2503 and prevents the plurality of apertures 2516 from adhering to the wall of the heart 2503.

[0061] However, in some cases, the placement of the heart pump assembly 2501 positions the plurality of apertures 2516 near the mitral valve leaflets 2574 at the entrance to the left atrium 2576. This can be due to the individual anatomical structure of a particular heart 2503. The mitral valve leaflets 2574 can be drawn towards the plurality of apertures 2516 by the suction of the pump and can be drawn against some of the plurality of apertures 2516 to block the inflow of blood passing through the plurality of apertures 2516. In some cases, particularly in a pump having a large inlet, such as the heart pump assembly 100 of FIG. 1, the mitral valve leaflet 2574 can be drawn into the cannula assembly 2508 through one of the plurality of apertures 2516, where the mitral valve leaflet 2574 blocks the blood flow passing through the cannula. The smaller sized plurality of apertures 2516 prevent the mitral valve leaflets from adhering to the plurality of apertures 2516. Further, the plurality of apertures 2516 enable the blood flow passing through the cannula assembly 2508 to be maintained despite the adhesion of the mitral valve leaflets 2574 or other tissue or tissue fragments to some of the plurality of apertures 2516. In another embodiment (not shown), the heart pump assembly may be designed to support the patient's right heart. In certain aspects, the device may be inserted percutaneously into the right atrium through the femoral vein or by other techniques. When the device is so positioned, the cannula of the assembly can extend into the pulmonary artery through the tricuspid and pulmonary valves. In this case, the plurality of apertures can be disposed at the inlet of the pump disposed in the inferior vena cava (IVC). As will be appreciated, such a device can include any of the above aperture configurations. The device may or may not include a non-invasive tip or protrusion.

[0062] FIG. 26 is a flowchart of a method of manufacturing a heart pump (e.g., heart pump assembly 200 of FIG. 2, heart pump assembly 400 of FIG. 4, heart pump assembly 2500 of FIG. 25 or any other suitable heart pump) of a particular embodiment having a plurality of openings in the distal end portion. Method 2600 can be implemented to form a heart pump having any number of openings disposed in any number of rings in the distal end portion. Method 2600 can be implemented for the manufacture of a heart pump assembly having openings of any size or shape having straight, chamfered, or rounded edges. In step 2602, an impeller blade is coupled to the rotor of the motor. The impeller blade can have any suitable number of blades and can be rotated by a drive shaft coupled to the motor. In some embodiments, the motor is configured to be external to the patient during operation of the pump. In some embodiments, the motor is integrated with the motor housing. In step 2604, the impeller blade is inserted into the motor housing. In step 2606, a cannula is coupled to the motor housing. The cannula can be attached to the distal end of the motor housing. In some embodiments, the cannula is expandable. In some embodiments, the cannula is self-expanding. In some embodiments, the cannula can be composed of a mesh, such as a nitinol mesh, covered by an elastic cover. In some embodiments, the cannula can be composed of a solid wire, such as a nitinol wire having a polymer cover or fabric.

[0063] In procedure 2608, couple the cannula to an inflow cage that includes a plurality of openings. In some embodiments, the inflow cage is constructed of stainless steel. The plurality of openings can be any number, shape, or size suitable for blood to pass through the openings in the inflow cage and into the cannula. The plurality of openings are radially oriented around the inflow cage. The plurality of openings are arranged into at least a first ring of openings and a second ring of openings proximal to the first ring of openings. The number of openings in a ring is 3, 4, 5, 6, 7, 8, 9, 10, or any other suitable number of openings. In some embodiments, the number of openings in the first ring is the same as the number of openings in the second ring. The first ring of openings extends to the end of the distal end portion of the inflow cage. In some embodiments, the plurality of openings further have more rings, such as a third ring proximal to the second ring and a fourth ring proximal to the third ring. Each of the plurality of openings can have an outer edge that is formed or deformed by tumbling in some embodiments.

[0064] The plurality of apertures can have a size, shape, number, or arrangement that serves to prevent the attachment or suction of heart tissue, such as valve leaflets, to or into the plurality of apertures (blocking the inflow of blood into the pump and limiting the efficiency of the heart pump). For example, in some embodiments, the height of the first aperture is less than 9 mm. In some embodiments, the height of the aperture of the first ring is 0.5 mm, 1 mm, 3 mm, 5 mm, 6 mm, 9 mm, 10 mm, 12 mm, 15 mm, or any other suitable height. In some embodiments, the height of the second aperture is less than 3 mm. In some embodiments, the height of the aperture of the second ring is 0.25 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 5 mm, 6 mm, or any other suitable height. In some embodiments, the width of the second aperture is less than 4 mm. In some embodiments, the width of the aperture of the second ring is 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 5 mm, 6 mm, 8 mm, or any other suitable width. In some embodiments, the height and width of the aperture of the third ring are the same as the height and width of the aperture in the second ring.

[0065] The area of each aperture can be different. In some embodiments, the area of the aperture in the first ring is larger than the area of the apertures in the other rings. In some embodiments, the area of the first aperture is less than 20 mm 2 In some embodiments, the area of the aperture of the first ring is 0.5 mm 2 , 1 mm 2 , 5 mm 2 , 10 mm 2 , 15 mm 2 , 18 mm 2 , 20 mm 2 , 23 mm 2 , 25 mm 2 or any other suitable area. The area of the aperture of the second ring can be less than 12 mm 2 In some embodiments, the area of the aperture of the second ring is 0.25 mm 2 , 0.5 mm 2 , 1 mm2 、 2 mm 2 、 5 mm 2 、 10 mm 2 、 12 mm 2 or any other suitable area.

[0066] The openings may have straight, rounded, or chamfered inner edges. In some embodiments, the openings have at least one chamfered edge. The chamfer can be at an angle of 45° or less with respect to a line perpendicular to the surface of the inflow cage. In some embodiments, the chamfered inner edge includes chamfers at 10°, 20°, 30°, 40°, 50°, >50°, or any other suitable angle. The use of chamfered inner edges can reduce hemolysis when blood enters the inflow cage. In some embodiments, the openings have at least one rounded edge. In some embodiments, the rounded inner edge includes a radius of curvature in the range of 40 microns to 105 microns.

[0067] In some embodiments, a plurality of openings are formed in the distal end portion of the cannula. In some embodiments, the distal end portion of the cannula is composed of stainless steel. The plurality of openings formed in the cannula can be any number, shape, or size suitable for blood to pass through the openings and enter the cannula. The plurality of openings can be radially oriented around the cannula. The plurality of openings are arranged at least in a first ring of openings and a second ring of openings proximal to the first ring of openings. The number of openings in the ring is 3, 4, 5, 6, 7, 8, 9, 10, or any other suitable number of openings. In some embodiments, the number of openings in the first ring is the same as the number of openings in the second ring. The first ring of openings extends to the end of the distal end portion of the cannula. In some embodiments, the plurality of openings further have more rings, such as a third ring proximal to the second ring and a fourth ring proximal to the third ring. Each of the plurality of openings can have an outer edge that is formed or deformed by tumbling in some embodiments.

[0068] In procedure 2610, a distal projection is coupled to the distal end of the inflow cage. The distal projection or atraumatic tip is distal to the plurality of apertures. The base of the distal projection may form the distal edge of the plurality of apertures in the first ring of apertures. In some embodiments, this procedure is optional and the distal projection is not attached to the heart pump. In some embodiments, the distal projection is configured as a pigtail. In some embodiments, the distal projection is configured as a flexible projection or extension. The distal projection is an atraumatic tip configured to space the plurality of apertures on the inflow cage from the heart wall. In some embodiments, the distal projection includes a lumen into which a guide wire can be inserted. The distal projection provides a mechanical extension of the cannula to prevent the plurality of apertures from suctioning onto the heart tissue.

[0069] FIG. 27 shows a flowchart of a method of using a heart pump having a plurality of apertures in a distal end portion (e.g., heart pump assembly 200 of FIG. 2, heart pump assembly 400 of FIG. 4, heart pump assembly 2500 of FIG. 25, or any other suitable heart pump). Method 2700 can be implemented to form a heart pump having any number of apertures arranged in any number of columns in a distal end portion. Method 2700 can be implemented for use with a heart pump assembly having apertures of any size or shape having straight, chamfered, or rounded edges. In step 2702, a pump motor is used to rotate an impeller about a rotational axis to draw blood into the cannula of the blood pump assembly from a plurality of blood inlet apertures. The motor can be external to the patient and connected to the impeller by a drive shaft. Alternatively, the motor can be incorporated within the pump and used internally. The blood inlet apertures can have any size, shape, or number. The blood inlet apertures are radially oriented around the cannula and are arranged in at least two rings at the distal end portion of the cannula. The size, shape, number, and location of the blood inlet apertures can be configured to reduce the occurrence of suction of heart tissue, valve leaflets, and other tissue pieces that occlude the inlet apertures.

[0070] In operation 2704, blood is discharged from a plurality of blood discharge openings disposed at the proximal end portion of the cannula proximal to the motor housing from the heart pump assembly. The blood can be sucked into the cannula from the blood inlet opening in the left ventricle and discharged from the blood discharge openings into the aorta above the aortic valve. The plurality of small inflow openings prevent or reduce the tendency for the openings to adhere to the heart structure or valve leaflets. The small openings reduce the potential damage to the heart structure that can be attracted to the pump, preventing the pump from sucking the leaflets into the inlet and enabling the pump to provide more support to the heart.

[0071] The foregoing merely illustrates the principles of the present disclosure, and the device can be implemented by other embodiments presented for purposes of illustration and not limitation. Although the device disclosed herein is shown with respect to use in a percutaneous heart pump, it will be understood that it can also be applied to devices in other applications that require empty openings for inflow.

[0072] After considering the present disclosure, those skilled in the art will envision variations and modifications. The disclosed features may be embodied in any combination and sub - combination (including multiple dependent and sub - combinations) with one or more of the other features described herein. The various features, including any of their components, may be combined or integrated into other systems. Moreover, certain features may be omitted or not implemented.

[0073] Examples of changes, substitutions, and modifications can be verified by those skilled in the art and can be implemented without departing from the scope of the information disclosed herein. All references cited herein are incorporated by reference in their entirety and are made a part of this application.

Claims

1. A rotor; A motor coupled to the rotor; An impeller blade coupled to the rotor such that rotation of the rotor rotates the impeller blade and pumps blood; A cannula assembly including the blood inlet, the cannula body, and a plurality of apertures radially oriented and disposed about a perimeter of the blood inlet and the cannula body; A heart pump assembly configured for percutaneous insertion, comprising: The plurality of apertures including a first row of apertures linearly spaced apart at least about a perimeter of the blood inlet, a second row of apertures laterally spaced from the first row of apertures about the perimeter of the blood inlet and proximal to the first row of apertures, a third row of apertures proximal to the second row of apertures, and a fourth row of apertures proximal to the third row of apertures, wherein a first aperture in the first row of apertures has an area larger than an area of a second aperture in the second row of apertures, an area of a third aperture in the third row of apertures, and an area of a fourth aperture in the fourth row of apertures; The heart pump assembly configured for percutaneous insertion into a patient's vasculature such that the impeller blade is disposed within the patient's vasculature.

2. The heart pump assembly of claim 1, wherein blood flows primarily through the most proximal aperture of the plurality of apertures.

3. The heart pump assembly of claim 1 or 2, wherein the first aperture in the first row of apertures and the second aperture in the second row of apertures are oval.

4. The heart pump assembly of any one of claims 1-3, wherein blood flows primarily through the fourth row of apertures.

5. The heart pump assembly of any one of claims 1-4, wherein a combined area of the plurality of apertures is equal to or greater than a cross-sectional area of the cannula assembly.

6. The heart pump assembly of any one of claims 1-5, wherein the first aperture in the first row of apertures and the third aperture in the third row of apertures are aligned along an axis on a surface of the cannula body parallel to a longitudinal axis of the cannula body.

7. The heart pump assembly of claim 6, wherein the second aperture in the second row of apertures is aligned with the fourth aperture in the fourth row of apertures along an axis on a surface of the cannula body parallel to a longitudinal axis of the cannula body.

8. The first opening in the first row of openings has a height measured parallel to the longitudinal axis of the cannula body, and this height is greater than the height of any of the second, third, or fourth openings, the heart pump assembly according to any one of claims 1-7.

9. The heart pump assembly according to claim 8, wherein the height of the first opening is less than 9 mm.

10. The heart pump assembly according to claim 9, wherein the height of the second opening is less than 3 mm.

11. The area of the first opening is less than 20 mm 2 The heart pump assembly according to claim 10, wherein the area of the first opening is less than 20 mm

12. The heart pump assembly according to claim 8, wherein the height of the second opening is the same as the height of the third opening and the height of the fourth opening.

13. The heart pump assembly according to claim 8, wherein the height of the second opening, the height of the third opening, and the height of the fourth opening are different from each other.

14. Each of the plurality of openings is defined by an inner edge intersecting the inside of the cannula body and an outer edge intersecting the outer surface of the cannula body, and the outer edge of each of the plurality of openings is rounded, or, Each of the plurality of openings is defined by an inner edge intersecting the inside of the cannula body and an outer edge intersecting the outer surface of the cannula body, and the outer edge of each of the plurality of openings is chamfered, The heart pump assembly according to any one of claims 1-13.

15. The heart pump assembly according to any one of claims 1-14, further comprising a distal protrusion coupled to the distal end of the cannula assembly.

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