Blood pump

Abstract

To provide a blood pump that achieves an improvement on a blood flow state at an inlet of a blood flow, or, in more detail, at a blood flow-through opening of a flow cannula.SOLUTION: A blood pump 1 includes a pump part 2 and a flow cannula 3. A proximal end part 14 of the flow cannula 3 is connected to the pump part 2 so that blood can enter a blood flow inlet 11. A distal end part 13 of the flow cannula 3 includes at least one blood flow-through opening 16 for the blood entering the flow cannula 3. The distal end part 13 includes an enlarged diameter part 15, and at least a main part of the blood flow-through opening 16 is disposed in the enlarged diameter part 15. The blood pump 1 further includes a sleeve 4 overlapping with the enlarged diameter part 15. The sleeve 4 has a structure for preventing its distal end part 42 from bending on a radial inner side in the blood flow-through opening 16.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to blood pumps, and more particularly to intravascular blood pumps, which support blood flow within a patient's blood vessels. [Background technology]

[0002] Various types of blood pumps are known, such as axial, centrifugal or mixed blood pumps, where blood flow is due to both axial and radial forces. An intravascular blood pump is inserted by a catheter into a patient's blood vessel, such as the aorta, and into a heart valve. A blood pump typically includes a pump section with a blood flow inlet and a blood flow outlet. To induce blood flow from the blood flow inlet to the blood flow outlet, vanes or rotors are typically rotatably supported within the pump casing about a rotation axis to carry blood. The blood pump may be driven by a motor contained within the blood pump adjacent to the pump section, or alternatively, by a motor outside the patient's body, connected to the vanes by a flexible drive shaft extending through the catheter.

[0003] The blood pump may be connected to a flow cannula that is in flow communication with the pump portion and may extend through a heart valve, such as the aortic valve, while the pump portion or at least the blood flow outlet of the pump portion is located outside the patient's heart, in a blood vessel, such as the aorta. The flow cannula has at least one blood flow-through opening for blood entering the flow cannula towards the blood flow inlet of the pump portion. Since the blood flow-through opening of the flow cannula is located in the patient's heart, such as the left ventricle, soft tissue, such as a filament in the left ventricle, may be sucked into the blood flow-through opening. This should be avoided for several reasons. On the one hand, damage to the soft tissue should be avoided. On the other hand, if the blood flow-through opening is blocked, this will result in failure of the blood pump and the blood pump must be removed or at least relocated. Summary of the Invention [Problem to be solved by the invention]

[0004] It is an object of the present invention to provide a blood pump which provides improved blood flow conditions at the blood flow inlet, and in particular at the blood flow-through opening of the flow cannula. [Means for solving the problem]

[0005] This object is achieved according to the invention by a blood pump having the features of the independent claim 1. Preferred embodiments and further developments of the invention are set out in the dependent claims.

[0006] According to the invention, the blood pump includes a flow cannula, such as an inflow cannula, the proximal end of which is connected to the pump section such that blood can enter a blood flow inlet of the pump section. The distal end of the flow cannula includes an enlarged diameter section and at least one radial blood flow-through opening for blood entering the flow cannula. At least a major portion of the blood flow-through opening is disposed within the enlarged diameter section. The blood pump further includes a sleeve proximal to the blood flow-through opening, the sleeve having a proximal end attached to the flow cannula, particularly the distal end of the flow cannula, and a distal end covering or overlapping the enlarged diameter section.

[0007] The sleeve has a structure that prevents at least the distal end from deflecting radially inwardly by more than 0.2 mm into the at least one blood flow-through opening during unobstructed operation of the blood pump within a patient. Unobstructed operation of the blood pump refers to an operating mode during normal, unobstructed conditions within a patient's body, such as operation of the blood pump at a flow rate of about 4-5 liters per minute. The sleeve preferably has a reinforcing structure that prevents the sleeve from collapsing during operation of the blood pump, as described in more detail below.

[0008] The above mentioned features and in particular their combinations may improve the blood flow at the blood inlet of the pump, in particular at the blood flow-through opening of the flow cannula which is usually placed in the patient's heart during operation of the blood pump. In other words, the blood pump of the present invention provides improved inflow characteristics. In particular, it is possible to prevent tissues that would block the opening, for example filaments in the left ventricle of the patient's heart, from being sucked into the blood flow-through opening. This can already be improved by providing an enlarged diameter section of the flow cannula, but is significantly improved by providing a sleeve that covers said enlarged diameter section, in particular the blood flow-through opening, in part or overlaps the blood flow-through opening. Another further improvement of the inflow characteristics may be achieved by providing the sleeve with a structure or reinforcing structure that prevents the sleeve from collapsing during operation of the blood pump and sucking itself into the blood flow-through opening. Furthermore, said reinforcement keeps the sleeve in a conical shape, thus allowing a gradual increase in blood velocity as blood enters the distal end of the cannula. Additionally, the amount of blood drawn into the blood flow-through opening, or flow rate, may be increased by providing a sleeve that directs blood flow toward the blood flow-through opening.

[0009] According to one aspect, at least the distal end of the flow cannula is radially expandable from a compressed or collapsed configuration to an expanded configuration. In particular, the expanded configuration defines an enlarged diameter section, while in the compressed or collapsed configuration, the diameter of the enlarged diameter section may be substantially equal to the diameter of the remainder of the flow cannula, which may be similarly expandable or may have a constant diameter. The expanded configuration resulting in an enlarged diameter section helps to avoid tissue suction into the flow cannula and enhances hemodynamics, while the compressed or collapsed configuration allows the blood pump to be delivered through the introducer sheath. To achieve the expansion characteristic, the distal end of the flow cannula may include a shape memory alloy material, such as Nitinol.

[0010] It is noted that increasing the inflow diameter of the cannula results in reduced suction in the inflow cannula and a reduction in the extent to which tissue aspirated into the inflow region affects blood flow into the cannula. In other words, assuming equal flow and pressure conditions in the inflow region, tissue aspirated into a smaller diameter of the cannula will have a greater effect on the flow rate into the cannula than if the same amount of tissue was aspirated into a larger diameter.

[0011] The distal end of the flow cannula, particularly the enlarged diameter section, more particularly the expandable enlarged diameter section, may include a framework structure, such as a cage, that defines a blood flow-through opening. The framework structure may define a number of struts, preferably extending axially, i.e. substantially in the direction of the longitudinal axis of the flow cannula. It will be appreciated that other strut designs are possible, such as radial struts, helical struts, or struts that enclose an angle with the longitudinal axis, or combinations thereof. At least one blood flow-through opening may be disposed on a radial circumferential surface of the distal end of the flow cannula. Radial openings are preferred over axial openings, as they may reduce tissue suction.

[0012] The sleeve preferably comprises a membrane of a highly flexible material, preferably polyurethane or any other suitable highly biocompatible material, in particular a polymer. The membrane may have a thickness of about 0.05 mm to 0.3 mm, such as 0.1 mm. With respect to the dimension of the sleeve in the longitudinal direction, the sleeve may extend along at least a portion of the enlarged diameter section of each blood flow-through opening, for example halfway along the enlarged diameter section. For example, the distal end of the sleeve may be disposed substantially at the maximum diameter of the enlarged diameter section or between the proximal end of the sleeve and the maximum diameter of the enlarged diameter section. The sleeve is preferably disposed around the circumferential surface of the distal end of the flow cannula. In an alternative embodiment, the sleeve may be disposed inside the flow cannula, in particular the framework structure.

[0013] The sleeve may have a funnel shape to direct the blood flow into the blood flow-through opening of the flow cannula. That is, the diameter of the sleeve increases toward its distal end, resulting in a tapered shape. In particular, it is advantageous if the sleeve is tapered exclusively in one direction, i.e., its diameter does not decrease after reaching a maximum diameter. The funnel shape is particularly useful for increasing the amount of blood drawn into the blood flow-through opening, since it gradually increases the linear blood flow velocity as the blood enters the funnel structure. For example, the flow rate may be increased by 0.5 liters per minute compared to a blood pump without a sleeve.

[0014] According to one aspect, the sleeve may be configured to radially expand or widen and collapse, preferably as a result of blood flow. In particular, the sleeve may include an expansion mechanism to allow the sleeve to expand or widen and collapse. The expansion mechanism may include, for example, at least one of at least one hinge, at least one magnet, a shape memory alloy, or a bimetal. Additionally or alternatively, such an expansion mechanism may be included in the flow cannula, in particular in the enlarged diameter portion thereof, and more particularly in the framework structure described above.

[0015] The sleeve may include guiding structures on the inner surface of the sleeve, such as at least one or more stator vanes, that may prevent the blood flow from rotating, inhibit vortices that would dissipate potential energy in the blood, and direct the blood flow longitudinally.

[0016] According to one aspect, as briefly mentioned in the preceding paragraph, the blood pump may include a reinforcing structure that increases the radial stiffness and prevents radial collapse of the sleeve. That is, the reinforcing structure ensures that the cross-sectional area of ​​the sleeve, at least in the area in which the reinforcing structure is arranged, is convex, e.g. circular, during operation of the blood pump in a plane perpendicular to the longitudinal axis. In general, a "convex" cross-sectional area means that the cross-sectional area has only radially outwardly curved or straight edges that do not form any notches, cutouts or radially inwardly bowed portions relative to the plane perpendicular to the longitudinal axis. The reinforcing structure is preferably arranged at least in or adjacent to the distal end of the sleeve. In other words, it may be advantageous or even sufficient if the open end of the sleeve, i.e. the end where the blood enters the sleeve, is reinforced so that during operation of the blood pump, the end does not collapse and remains open, allowing blood to enter the blood flow-through opening of the sleeve and the flow cannula. However, it will be appreciated that the reinforcing structure may nevertheless be collapsible, in particular for insertion or removal of the blood pump through the catheter, as described in more detail below, i.e., during operation of the blood pump, the reinforcing can withstand any forces, in particular radial forces, that arise so that the sleeve does not collapse, but if a sufficiently strong force is applied, for example during removal or preparation of the blood pump prior to insertion into the catheter, the radial stiffness of the reinforcing structure may be overcome to collapse or fold the sleeve into a collapsed configuration.

[0017] Thus, according to one aspect, the reinforcement structure may be radially expandable or can expand from a collapsed configuration to an expanded configuration, thereby allowing the blood pump to be delivered through an introducer sheath. The reinforcement structure is preferably also collapsible or foldable, conversely, to facilitate removal of the blood pump from the patient's body. At the same time, the reinforcement structure may provide a sufficiently high stiffness in the expanded configuration to prevent the sleeve from collapsing during operation of the blood pump. However, the reinforcement structure may be designed such that it can be collapsed by application of a sufficiently strong force, for example by retracting the blood pump into a catheter for removal from the patient's body.

[0018] In one embodiment, the structure of the sleeve, or in particular the reinforcing structure, may include at least one inflatable structure extending at least partially circumferentially around the sleeve. The reinforcing structure may include, for example, at least one annular balloon. The balloon may be disposed on the outer surface of the sleeve such that it projects radially outward from the sleeve and helps to keep soft tissue away from the blood flow-through opening. Alternatively or in addition to the annular balloon, the entire sleeve may be inflatable or may include not only an annular structure that reinforces the sleeve and prevents it from collapsing. Furthermore, the inflatable structure may be provided with the flow cannula to increase stiffness or to keep soft tissue away from the inlet opening. For example, a soft tip, such as a pigtail or J-tip, which may be inflatable, may be provided at the distal end of the cannula. Of course, any of the inflatable structures described above may also be collapsible to facilitate removal from the patient's body.

[0019] Alternatively or additionally, the structure of the sleeve, or in particular the reinforcing structure, may include at least one elastic member extending at least partially circumferentially around the sleeve. For example, the reinforcing structure may include at least one band or wire extending at least partially circumferentially around the sleeve and including at least one of a shape memory alloy, a metal, and a polymeric material. The band or wire may extend around the circumference of the sleeve along a straight line or with an undulating or zigzag shape.

[0020] Alternatively or additionally, the structure of the sleeve, or in particular the reinforcing structure, may include at least one elastic member extending at least partially circumferentially around the sleeve. The elastic member may for example include a tube section and a wire section attached to an end of the tube section, such that the free end of the wire section may be inserted into the free end of the tube section to form an elastic ring. The elastic member may be made of a shape memory alloy, such as Nitinol.

[0021] In one embodiment, at least two sleeves, such as two, three or four sleeves, may be arranged in series on the distal end of the flow cannula so that blood can enter each of the sleeves toward the blood flow-through opening. For example, the sleeves may be arranged such that the proximal end of one sleeve is disposed within the region of the distal end of an adjacent sleeve and blood can enter the distal end of each sleeve. Alternatively, the distal end of one sleeve may be connected to the proximal end of an adjacent sleeve by a structure that provides an opening so that blood can enter each of the sleeves from the distal end. The sleeves may be arranged in the manner of pine cone scales or form a caterpillar-like shape.

[0022] The foregoing summary, as well as the following detailed description of the preferred embodiments, will be better understood when read in conjunction with the appended drawings. For purposes of illustrating the present disclosure, reference is made to the drawings. However, the scope of the disclosure is not limited to the specific embodiments disclosed in the drawings. [Brief description of the drawings]

[0023] [Figure 1] 1 is a partial cross-sectional view of a patient's heart along with one embodiment of a blood pump. [Figure 2A] 2 is a different view of the end of the blood pump of FIG. 1 in a first configuration; [Figure 2B] 2 is a different view of the end of the blood pump of FIG. 1 in a first configuration; [Figure 2C] 2 is a different view of the end of the blood pump of FIG. 1 in a first configuration; [Figure 3A] 2 is a different view of the end of the blood pump of FIG. 1 in a second configuration. [Figure 3B] 2 is a different view of the end of the blood pump of FIG. 1 in a second configuration. [Figure 4A] 2 is a different view of the end of the blood pump of FIG. 1 in a third configuration. [Figure 4B] 2 is a different view of the end of the blood pump of FIG. 1 in a third configuration. [Figure 5A] 11A-11C are different views of the end of a blood pump according to another embodiment. [Figure 5B] 11A-11C are different views of the end of a blood pump according to another embodiment. [Figure 6] FIG. 13 is a side elevational view of an end portion of a blood pump according to another embodiment. [Figure 7] FIG. 13 is a diagram of a reinforcing member for a sleeve. [Figure 8] 13 is a side elevational view of an end of a blood pump according to another embodiment, the blood pump including two or more sleeves. [Figure 9] FIG. 13 is a side elevational view of an end portion of a blood pump according to another embodiment. [Figure 10A] FIG. 13 is a diagram of an inflow cage at the end of a blood pump according to another embodiment. [Figure 10B] FIG. 13 is a diagram of an inflow cage at the end of a blood pump according to another embodiment. [Figure 11A] FIG. 13 is a diagram of an inflow cage at the end of a blood pump according to another embodiment. [Figure 11B] FIG. 13 is a diagram of an inflow cage at the end of a blood pump according to another embodiment. [Figure 12A] 11A-11C are different views of an inflow cage at the end of a blood pump according to another embodiment. [Figure 12B] 11A-11C are different views of an inflow cage at the end of a blood pump according to another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] In FIG. 1, a blood pump 1 is shown inserted into a patient's heart 100. More specifically, the blood pump 1 is connected to a catheter 10 by which the blood pump 1 is inserted into a left ventricle 105 of the patient's heart 100 via an aorta 101, including a descending aorta 102 and an aortic arch 103. In operation, the blood pump 1 is positioned through an aortic valve 104. The blood pump 1 includes a pump portion 2 and a flow cannula 3. The pump portion 2 has a blood flow outlet 12 disposed outside the patient's heart 100 in the aorta 102, while a blood flow inlet (shown at 11) of the pump portion 2 is in flow communication with the flow cannula 3. Vanes (not shown) are provided to effect blood flow. The flow cannula 3 extends through the aortic valve 104 into the left ventricle 105 and has a proximal end 14 connected to the pump portion 2 and a distal end 13. To pump blood through the flow cannula 3 into the pump portion 2 and out the blood flow outlet 12, the distal end section 13 has an enlarged diameter section 15 with a blood flow-through opening 16, described in more detail below. A soft tip 20, such as a pigtail or J-tip, is disposed at the distal end of the blood pump 1 to facilitate insertion of the blood pump 1 into the patient's heart 100 without causing any damage to the surrounding tissue. The soft tip 20 also helps to keep soft tissue away from the flow cannula 3. The end of the blood pump 1 is designated EP, which is shown in more detail in FIG. 2A. In general, the term "proximal" refers to a direction toward the user, while the term "distal" refers to a direction away from the user.

[0025] 2A-2C, the distal end EP is shown in more detail in a first configuration during operation of the blood pump 1, i.e. under normal conditions including cardiac pressure and flow rate, e.g. 4 liters per minute flow rate. The blood flow-through openings 16 are formed by a framework structure such as a cage including struts 17 separating the blood flow-through openings 16 from each other. In this embodiment, the struts 17 are shown extending substantially axially, along the longitudinal axis 18 of the flow cannula 3. Of course, the struts 17 may also extend radially or helically or form any other suitable shape to form the blood flow-through openings 16. In this embodiment, five struts 17 form a cage with blood flow-through openings 16. However, there may be fewer struts, such as three or four, or more struts, such as six, seven or eight.

[0026] A sleeve 4 is provided covering or overlapping the enlarged diameter section 15 of the distal end 13 of the flow cannula 3, more specifically the blood flow-through opening 16. The sleeve 4 has a proximal end 41 attached to the distal end 13 of the flow cannula 3 at a location proximal to the blood flow-through opening 16, and a distal end 42. That is, the sleeve 4 covers the proximal part of the blood flow-through opening 16, for example the proximal half of the blood flow-through opening 16. By providing the sleeve 4, tissue suction into the blood flow-through opening 16 can be reduced. The sleeve 4 has a funnel shape, i.e. its diameter increases in the direction from the proximal end 41 to the distal end 42. It is preferred that the sleeve 4 does not narrow at its distal end 42. The funnel shape can increase the blood flow rate of the blood pump 1.

[0027] 2A and 2B, the cross-sectional area of ​​the sleeve 4 in a plane perpendicular to the longitudinal axis 18 is substantially circular. As shown, the sleeve 4 may be supported by the cage. However, the sleeve 4 may provide a larger diameter than the cage. Under ideal conditions, the sleeve 4 may be held open by the blood flow and may provide sufficient stability to resist collapse during operation of the blood pump 1. This may be achieved by selecting an appropriate material for the sleeve 4 or by providing a reinforcing structure, which is described in more detail below.

[0028] During operation of the blood pump 1, the sleeve 4 may take other shapes that are not substantially circular. As shown in Figures 3A and 3B, if the cage includes five struts 17, the sleeve 4 may be fitted around the struts 17 so that the cross-sectional area of ​​the sleeve forms a pentagon. In particular, as shown in Figures 4A and 4B, as a result of the pressure distribution at the distal end 42 of the sleeve 4, the sleeve 4 may also flex slightly inward from the struts 17 into the blood flow-through opening 16. Of course, the flexure should be no more than 0.2 mm radially inward on each side to avoid adverse effects on the blood flow. In particular, the sleeve 4 has sufficient rigidity to prevent the sleeve from being sucked into the blood flow-through opening 16, which would potentially block the blood flow-through opening.

[0029] In general, the cage and sleeve 4 and optionally also the flow cannula 3 may provide an expansion characteristic. That is, the above-mentioned parts of the blood pump 1 may assume an expanded configuration, providing an enlarged diameter, and the collapsed or compressed configuration provides a smaller diameter. In particular, an enlarged diameter section 15 may be defined in the expanded configuration, while in the compressed configuration, the diameter of section 15 is substantially the same as the diameter of the remainder of the flow cannula 3, allowing the blood pump 1 to be delivered through an introducer sheath. Once delivered to a target site, e.g., a patient's heart as described above in connection with FIG. 1, the blood pump 1 may be released to assume the expanded configuration.

[0030] The sleeve 4 may have a structure that provides sufficient radial stiffness to prevent the sleeve 4 from collapsing during operation of the blood pump 1, for example a structure including a membrane of a suitable material such as polyurethane, but may also be provided with additional reinforcing structure attached to or embedded in the sleeve 4. It will be appreciated that the reinforcing structure provides high radial stiffness during operation of the blood pump 1, but at the same time provides expansion and compression properties as described above, allowing the blood pump to assume an expanded or spread out and compressed or collapsed configuration.

[0031] 5A and 5B, the sleeve 4 has a reinforcing structure in the form of an inflatable device, such as an annular balloon 30. The balloon 30 may be inflated and deflated by a tube (not shown) with a suitable fluid, such as a gas or liquid. The balloon 30 may be attached to the circumference of the distal end 42 of the sleeve 4, or may be attached to the sleeve 4 at any other suitable location, or may be embedded within the sleeve 4. Additionally, there may be more than one inflatable annular balloon or another inflatable structure that provides radial stiffness for the sleeve 4. The inflatable structure is preferably also collapsible to facilitate removal of the blood pump 1 from the patient's body.

[0032] Further embodiments of reinforcing structures that may be used as an alternative to, or possibly in addition to, the inflatable balloon 30 are shown in Figures 6 and 7. In Figure 6, a reinforcing structure is shown formed by a band 31 comprising a shape memory alloy such as Nitinol. For example, the band 31 may comprise a zigzag structure of Nitinol wire. However, the band 31 may comprise other structures that provide radial stiffness as well as expansion and compression properties during operation of the blood pump 1, or may comprise other materials, such as metals or polymers.

[0033] The reinforcing structure shown in FIG. 7 is formed by an elastic member 32. The elastic member 32 includes a tube portion 34 and a wire portion 33 attached to the tube portion 34, the free end of which is slidably insertable into the tube portion 34 to form an elastic ring. The elastic member 32 provides radial stiffness for the sleeve 4, but allows for the change in its diameter to allow for the expanded and compressed configurations as described above. The band 31 and elastic member 32 may be attached to the sleeve 4 at the distal end 42 of the sleeve, holding the distal end 42 open. However, it will be appreciated that the band 31 and elastic member 32 may be attached to or embedded in the sleeve 4 at other suitable locations to provide the aforementioned properties.

[0034] FIG. 8 illustrates an embodiment in which two or more, here three, sleeves 4', 4'', 4''' overlap each blood flow-through opening 16', 16'', 16''' formed by struts 17', 17'', 17'''. Blood flow-through openings 16', 16'', 16''' and struts 17', 17'', 17''' may be formed like blood flow-through openings 16 and struts 17, respectively, described hereinabove. Similarly, sleeves 4', 4'', 4''' may be formed like sleeve 4, described hereinabove, with or without additional reinforcing structure. This arrangement may help keep soft tissue away from the blood flow-through openings.

[0035] Another embodiment of the distal end EP of the blood pump is shown in FIG. 9. In this embodiment, the sleeve 40 is disposed inside the cage, rather than around it. That is, the sleeve 40 overlaps the blood flow-through opening 16 from the inside. Blood can enter the sleeve 40, and thus the flow cannula 3, without aspirating the soft tissue. The soft tissue is kept away from the open end of the sleeve by the struts 17. Furthermore, the sleeve 40 may be attached by adhesive or any other means to the inner surface of the struts 17 (not shown) to keep the sleeve 40 open at all times, or it may be left free from the struts 17, as shown in FIG. 9. It is contemplated that a reinforcing inflatable circular balloon (not shown in FIG. 9) similar to the balloon 30 shown in FIGS. 5A and 5B may be used as described above to keep the sleeve 40 open and in a circular shape during use of the device. It is contemplated that an elastic member (not shown in FIG. 9) similar to elastic member 32 shown in FIG. 7 may be used as described above to hold sleeve 40 open and in a circular shape during use of the device.

[0036] 10A and 10B show an inflow cage at the end of a blood pump according to another embodiment. This embodiment is substantially similar to the previous embodiment, and like reference numbers refer to like elements. For illustrative purposes, the sleeve is omitted in FIGS. 10A and 10B. The inflow cage, which forms an enlarged diameter section 15, includes four struts 17 and a blood flow-through opening 16. The inflow cage further includes a support structure that provides additional support for the sleeve. The support structure may extend from the proximal end of the inflow cage substantially half the length of the inflow cage or less than half the length of the inflow cage, or may correspond to the length of the sleeve.

[0037] The support structure includes arches 19, four in this embodiment, connecting adjacent struts 17. The arches 19 may have any suitable shape, such as pointed, rounded or otherwise curved, or may have a protrusion-like shape. The arches 19 may be disposed radially inward or at substantially the same radius as the struts 17, as shown in FIG. 10A, or may extend radially outward beyond the struts 17, as shown in FIG. 10B. In an embodiment, the configuration shown in FIG. 10A may be referred to as a compressed configuration, and the configuration shown in FIG. 10B may be referred to as an expanded configuration. The inflow cage may be made of a shape memory alloy, such as Nitinol.

[0038] 11A and 11B show an inflow cage at the end of a blood pump according to another embodiment, which is substantially the same as the embodiment shown in FIG. 10A and 10B. The inflow cage may be made of Nitinol and may provide various configurations, such as compression and expansion. As shown in FIG. 11A, the arches 19 are disposed radially inward relative to the struts 17, whereas in FIG. 11B, the struts are disposed radially outward relative to the struts 17.

[0039] 12A and 12B show different views of an inflow cage at the end of a blood pump according to another embodiment, which is similar to the embodiment shown in FIGS. 10A and 10B. The inflow cage includes five struts 17 that are substantially identical to the struts in the other embodiments. The inflow cage includes a support structure that provides additional support for a sleeve (sleeve not shown in FIGS. 11A and 11B). The support structure includes additional struts 19'' with a fork portion 19' toward the proximal end such that the additional struts 19'' branch off into separate branches 19'''. With reference to the embodiment of FIGS. 10A-11B, it is considered that the fork portion 19' can be considered as an arch 19, whereby additional struts 19'' are connected to the free distal end of each of the arches 19. Or in other words, it is believed that the inflow cage of the embodiment of Figures 12A and 12B may be considered to have a plurality of struts 17 and 19'', whereby at least some of the struts fork or branch towards their proximal ends to form a support structure for the sleeve. The branches 19''' of each strut 19'' may connect to adjacent struts 17, as shown in Figures 12A and 12B. As with the previous embodiment, the inflow cage is preferably made of Nitinol.

[0040] It should be understood that the described embodiments are illustrative only and not restrictive. In particular, it is contemplated that various aspects and features of the embodiments may be combined in different embodiments or may be used alone. For example, it is contemplated that the features described with respect to the sleeve and reinforcing structure may be variably combined without departing from the scope of the invention.

Claims

1. A blood pump (1) comprising a pump portion (2) and a flow cannula (3), said pump portion (2) having a blood flow inlet (11) and a blood flow outlet (12) and vanes for conveying blood from said blood flow inlet (11) to said blood flow outlet (12), said flow cannula (3) having a general longitudinal axis (18) with a distal end (13) and a proximal end (14); the proximal end (14) of the flow cannula (3) is connected to the pump portion (2) such that the blood can enter the blood inlet (11); the distal end (13) of the flow cannula (3) includes an enlarged diameter section (15) and at least one radial blood flow-through opening (16) for the blood entering the flow cannula (3), at least a major portion of the at least one blood flow-through opening (16) being disposed within the enlarged diameter section (15); The blood pump (1) further includes a sleeve (4) having a proximal end (41) attached to the flow cannula (3) proximal to the blood flow-through opening (16) and a distal end (42) overlapping the enlarged diameter section (15), the sleeve (4) having a structure that prevents the distal end (42) from deflecting radially inwardly into the at least one blood flow-through opening by more than 0.2 mm during unobstructed operation of the blood pump (1) within a patient. A blood pump (1).

2. 2. The blood pump of claim 1, wherein at least the distal end of the flow cannula is radially expandable from a compressed configuration to an expanded configuration.

3. 3. The blood pump of claim 2, wherein the expanded configuration defines the enlarged diameter portion, while in the compressed configuration the diameter of the enlarged diameter portion is substantially equal to the diameter of the remainder of the flow cannula.

4. 4. The blood pump of claim 1, wherein the distal end of the flow cannula includes a framework defining the blood flow-through opening.

5. 5. The blood pump of claim 4, wherein the framework includes a plurality of struts extending substantially in the direction of a longitudinal axis of the flow cannula.

6. 6. A blood pump according to any one of claims 1 to 5, characterized in that at least the distal end of the flow cannula comprises a shape memory alloy material, preferably Nitinol.

7. 7. The blood pump according to claim 1, wherein the at least one blood flow-through opening is disposed on a radial circumferential surface of the distal end of the flow cannula.

8. 8. A blood pump according to any one of the preceding claims, characterized in that the sleeve comprises a membrane of flexible material, preferably polyurethane.

9. 9. A blood pump as claimed in any one of claims 1 to 8, characterized in that the distal end of the sleeve is disposed at substantially the maximum diameter of the enlarged diameter section, or the distal end of the sleeve is disposed between the proximal end of the sleeve and the maximum diameter of the enlarged diameter section.

10. 10. The blood pump according to claim 1, wherein the sleeve has a funnel shape for directing blood flow into the blood flow-through opening of the flow cannula.

11. 11. The blood pump of claim 1, wherein the sleeve is disposed around a circumferential surface of the distal end of the flow cannula, or the sleeve is disposed inside the flow cannula.

12. 12. A blood pump according to any one of claims 1 to 11, characterized in that the sleeve is configured to radially expand or widen, preferably as a result of the blood flow.

13. 13. The blood pump of any one of claims 1 to 12, wherein at least one of the enlarged diameter section of the flow cannula and the sleeve includes an expansion mechanism to allow the section or sleeve to expand or spread and compress or collapse.

14. 14. The blood pump of claim 13, wherein the expansion mechanism includes at least one of at least one hinge, at least one magnet, a shape memory alloy, or a bimetal.

15. 15. A blood pump as claimed in any one of claims 1 to 14, characterized in that the sleeve includes a guide structure on an inner surface of the sleeve for directing the blood flow longitudinally, the guide structure preferably including a plurality of stator vanes.

16. 16. A blood pump according to claim 1, characterized in that the structure of the sleeve is a reinforcing structure, which is radially stiff and includes a reinforcing structure that provides a convex cross-sectional area of ​​the sleeve at least in the area where the reinforcing structure is disposed in a plane perpendicular to the longitudinal axis.

17. 17. The blood pump of claim 16, wherein the reinforcing structure is disposed at least at or adjacent the distal end of the sleeve.

18. 18. The blood pump of claim 16 or 17, wherein the reinforcement structure is radially expandable from the compressed configuration to the expanded configuration.

19. 19. A blood pump according to any one of claims 1 to 18, characterized in that the sleeve structure includes at least one inflatable structure extending at least partially circumferentially around the sleeve.

20. 20. A blood pump according to any one of claims 1 to 19, characterized in that the sleeve structure includes at least one annular balloon.

21. 21. A blood pump as claimed in any one of claims 1 to 20, characterized in that the structure of the sleeve includes at least one elastic member extending at least partially circumferentially around the sleeve.

22. 22. A blood pump as claimed in any one of claims 1 to 21, characterized in that the structure of the sleeve includes at least one band or wire extending at least partially circumferentially around the sleeve and comprising at least one of the shape memory alloy, metal and polymeric material.

23. 23. A blood pump as claimed in any one of claims 1 to 22, characterized in that the structure of the sleeve includes at least one elastic member extending at least partially circumferentially around the sleeve.

24. 24. The blood pump of claim 1, wherein at least two sleeves are disposed in series on the distal end of the flow cannula such that the blood can enter each of the sleeves toward the blood flow-through opening.

25. 25. A blood pump according to any one of the preceding claims, characterized in that the blood pump is an intravascular blood pump.

26. 26. The blood pump according to any one of claims 1 to 25, characterized in that the blood pump is an axial blood pump, a centrifugal blood pump or a mixed type blood pump.

Images