Blood pump

Abstract

To provide a blood pump in which a pump housing, a shaft arrangement and a conveying element are coordinated with one another in such a way that these guarantee the best possible efficiency and longevity of the pump.SOLUTION: A housing 80 comprises a pump-receiving portion 85, a proximal portion 84, and a distal portion 86. In an expanded state, the proximal portion 84 and the distal portion 86 each includes multiple helical structures extending along the longitudinal axis helically around the longitudinal axis. Each helical structure in the proximal portion 84 is wound in a first direction as considered from the proximal end 84 to the distal end 86. Each helical structure in the distal portion 86 is wound in a direction opposite to the first direction.SELECTED DRAWING: Figure 7b

Description

[Technical Field]

[0001] The present invention lies in the fields of mechanics, precision mechanics and materials technology and relates to pumps or pump components, in particular blood pumps. [Background technology]

[0002] In the prior art, pumps are known that have a pump housing with a proximal end and a distal end disposed therebetween, a drive shaft disposed longitudinally inside the pump housing, a conveying element disposed on the drive shaft, and a cannula or catheter disposed proximal to the pump housing. Pumps of this type often have a flexible drive shaft, allowing the pump to be guided even in difficult-to-access locations and perform its pumping function there. One example is a blood pump, which is inserted, for example, through the femoral artery and the aortic arch into the left ventricle of the heart and remains in the region of the aortic valve. At the proximal end of the pump, i.e., for example, at the end of the drive shaft that remains outside the body, the pump can be connected to a motor, which drives the drive shaft and thus the conveying element disposed on the drive shaft, where the pump is disposed, for example, in the left ventricle. Thus, blood can be pumped from the ventricle to the aorta.

[0003] In such pumps, it is known that the pump housing is configured so that it can be at least partially displaced into a cannula or catheter under the application of a force acting on the proximal end of the pump. In other words, for example, by applying a tensile force in the region of the proximal end of the drive shaft, the pump housing can be pulled into the cannula and thus brought from an expanded state with a larger radial expansion to a compressed state with a smaller radial expansion. This transition is provided, among other things, before the pump is inserted into and removed from the body, because the reduced diameter of the pump housing facilitates navigation of the distal end of the pump within the human body and, among other things, ensures a minimally invasive passage through the skin. Here, the pump housing is usually made of metal, for example, a shape-memory metal. Other materials can be used for the pump housing, provided they can withstand the mechanical stresses during compression and expansion and meet medical hygiene standards.

[0004] In the case of pumps of this type, it is also common for the conveying element, such as the rotor, to include at least one foldable or flexible segment, e.g., in the form of a rotor blade. Examples of rotors of this type are described, for example, in U.S. patent application Ser. No. 13 / 261,565, the disclosure of which is incorporated herein by reference in its entirety. Additionally, U.S. patent application Ser. No. 13 / 261,100 is likewise incorporated herein by reference in its entirety.

[0005] With respect to pump housings, reference is made, by way of example, to U.S. Patent Application No. 13 / 146,452, which is also incorporated herein by reference in its entirety, and to U.S. Patent Application No. 13 / 261,256, which is also incorporated herein by reference in its entirety.

[0006] When designing the pump housing, it has proven possible to generate a section that, in the expanded state of the pump housing, winds around the longitudinal axis in a spiral manner when considered along a longitudinal axis extending along the drive shaft from the proximal end to the distal end of the pump. However, here, a structure extending in a spiral or helical manner, in particular a spiral or helical strut, should not be understood to mean that it must completely surround the longitudinal axis. It can also be understood to mean simply a portion of a spiral that forms a segment of the spiral around the longitudinal axis, i.e., a curved strut can also be referenced that substantially follows a spiral course around the longitudinal axis over a portion.

[0007] Through the development of this type of pump, the inventors have determined that advantageous coordination between the pump housing, drive shaft, and conveying elements helps to produce an efficient blood pump that can be implanted for relatively long periods of time. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] European Patent Application Publication No. 2868289 Summary of the Invention [Means for solving the problem]

[0009] This object is achieved by a blood pump according to the features of claim 1.

[0010] According to a first embodiment of the present invention, the spirally extending structures or spirally extending structure (singular) are formed so that a torque directed opposite to the first direction acts on the foldable segments when the pump housing is moved from an expanded state to a compressed state. It should be noted here that reference is frequently made to torque acting in a clockwise or counterclockwise direction in this application. More specifically, reference is not made to torque but to the direction of the force that generates the torque. Torque is the vector product of a radial position vector directed outward from the longitudinal axis and the generated force, and therefore extends perpendicular to the generated force. In other words, when reference is made to torque extending in a clockwise direction, this rather refers to torque extending parallel to the longitudinal axis. However, for the sake of simplicity and improved orientation, the direction of torque is often equated with the direction of the generated force, which does not correspond to a physical definition.

[0011] The portion including the helically extending structure preferably forms only a limited portion of the pump housing. This portion causes a torque to develop when the pump housing is retracted into the cannula, the torque being directed opposite to the direction of the helical winding. Due to its configuration and its flexible or foldable segments, the rotor has a tendency to wrap around the drive shaft in a particular direction when the housing compresses. Because torque is created when the housing compresses, this likewise acts on the foldable segments, thus, for example, can urge the foldable segments in a predetermined folding direction relative thereto.

[0012] This means that the torque applied by the pump housing assists the natural folding of the flexible segments around the drive shaft, thus resisting damage to the rotor.

[0013] In a first embodiment, the foldable segments of the conveying element are configured such that a torque in the rotational direction of the conveying element corresponds to the conveyance of fluid from the distal end to the proximal end of the pump. In other words, when fluid is conveyed from the distal end to the proximal end of the pump, the first direction in which the helical structure extends is opposite to the rotation of the conveying element during operation, when the flexible segments of the conveying element are configured accordingly. Surprisingly, it has been found that both an improvement in the efficiency of the pump is possible as a result, and that potential damage to the pump housing can be reduced.

[0014] In a further embodiment, the foldable segments of the conveying element are generated such that the torque is directed opposite to the rotation direction of the conveying element, and in addition, the deployment direction of at least one foldable segment during deployment extends in a first direction, which means that the rotation direction of the conveying element when conveying fluid from the distal end to the proximal end is directed opposite to the deployment direction of the rotor.

[0015] In a further embodiment, the collapsible segments of the conveying element may be configured such that torque is directed opposite the direction of rotation of the conveying element to convey fluid from the distal end to the proximal end of the pump.

[0016] In a further embodiment, the deployment direction of the at least one foldable segment during deployment is opposite to the first direction.

[0017] In a further embodiment, the pump housing is made from a shape memory material, where the pump housing may be manufactured from, for example, Nitinol.

[0018] A further example is the "austenite finish" (A f) temperature is lower than the body temperature of a healthy person, in particular lower than 30°C, in particular lower than room temperature, i.e. lower than 20°C. f It has been found that the stability and lifespan of the housing can be improved at high temperatures. f This is true when the temperature is below room temperature.

[0019] In a further embodiment, the pump housing includes a pump receiving portion and a proximal portion disposed proximally of the pump receiving portion, the inner diameter of the proximal portion being reduced from the diameter of the pump receiving portion to the proximal end of the proximal portion in the inflated state of the pump housing. With this type of pump housing, retraction into the cannula is facilitated and supported due to the shape of the pump housing. Here, a variant of the pump according to the invention is provided, in which the helical structure is disposed in the proximal portion.

[0020] In an alternative embodiment, the helical structure is disposed on the pump-receiving portion. In a further embodiment, the helical structure is disposed on both the proximal portion and the pump-receiving portion.

[0021] In a further embodiment, the pump housing includes a further distal portion disposed distal to the pump receiving portion, the inner diameter of the further distal portion preferably being reduced from the diameter of the pump receiving portion to the distal end of the distal portion in the inflated state of the pump housing.

[0022] The drive shaft can therefore be journalled by additional bearings, for example in the region of reduced inner diameter in the distal portion, so that improved protection of the rotor is possible.

[0023] In some embodiments, a helical structure is also disposed in the distal portion. Here, the helical structure may be wound or wound in the opposite direction to the first direction. In this embodiment, the helical structure assists in the generation of torque in both the proximal and distal portions, and although the generation of torque is initiated throughout the pump housing between the proximal and distal portions, the torque causes bending or twisting of the helical element only in the regions of the proximal and distal portions. In a variant, the helical structure in the proximal and distal regions is formed so that the torque is directed in the same direction proximally and distally and / or so that the proximal and distal torques are of the same magnitude. This is similar to the packaging of a candy in a candy wrapper; the candy can be opened from the wrapper by holding both ends and pulling simultaneously. Thus, for example, the drive shaft is prevented from twisting, and therefore the drive shaft is protected against damage.

[0024] In a further embodiment, the drive shaft is alternatively or additionally journalled in the region of the proximal end of the pump housing.

[0025] The blood pump of the present invention has a pump housing having a proximal end and a distal end and disposed therebetween, a drive shaft disposed inside the pump housing along a longitudinal direction, and a conveying element disposed on the drive shaft, wherein the conveying element includes at least one flexible segment, and the at least one flexible segment is configured such that a rotational direction of the conveying element causes fluid to be conveyed from the distal end to the proximal end of the blood pump, and the pump housing is configured such that the pump housing can be at least partially displaced into a cannula under the application of a force acting on the proximal end of the blood pump, and the pump housing comprises at least the pump housing is moved from an inflatable state to a compressed state at least along a radial direction extending transverse to the longitudinal direction when the pump housing is moved partially into the cannula, the deployment direction of the at least one flexible segment is oriented opposite to the rotational direction when the pump housing is pulled out of the cannula from the compressed state to the expanded state, the conveying element is constructed from a single piece of plastic, the pump housing has helical struts at the proximal and distal portions and lattice-shaped struts between the proximal and distal portions, and the deployment direction of the at least one flexible segment is in the same direction as the spiral direction of the struts. That is, in this aspect of the invention, when the pump housing is moved from the compressed state to the expanded state, the deployment direction of the at least one flexible element is provided opposite to the rotational direction of the conveying element when fluid is conveyed from the distal end to the proximal end of the pump, regardless of its helical structure. In this case, as in the first aspect of the invention, it should be understood that the movement of the outer ends of the segments of the conveying elements refers to the direction of deployment when considered radially.

[0026] A blood pump according to a reference example includes a pump housing, a drive shaft disposed inside the pump housing along a longitudinal axis, and a conveying element disposed on the drive shaft, the pump housing including at least one pump receiving portion and a proximal portion disposed proximal to the pump receiving portion, the pump housing being movable from a compressed state to an expanded state in a radial direction extending transverse to the longitudinal direction, the drive shaft journaled in a proximal bearing in a region of the proximal portion of the pump housing, the drive shaft being configured such that the stiffness of the drive shaft in the region of the proximal portion of the pump housing and distal to the proximal bearing is adjusted to the stiffness of the proximal portion, and the conveying element is disposed substantially concentrically within the pump receiving portion when the pump housing is bent. The pump housing includes at least one pump receiving portion and a proximal portion disposed proximally of the pump receiving portion, and the pump housing can be moved from a compressed state to an expanded state in a radial direction extending transversely to the longitudinal direction. The drive shaft is journaled in a proximal bearing in the region of the proximal end of the pump housing.

[0027] In the illustrated embodiment, the drive shaft is configured so that its stiffness in the region of the proximal portion of the pump housing and its stiffness distal to the proximal bearing correspond to that of the proximal portion of the pump housing. In this way, in the event of any bending, the pump housing and the conveying element are mounted / supported substantially concentrically with each other within the pump receiving portion. In other words, the bending line of the pump housing in the proximal portion is aligned with the bending line of the flexible shaft in the region of the proximal portion, so that a bending moment acting on the distal end of the pump housing induces a similar bending in both the housing and the shaft. Therefore, due to the different resistances to bending, the rotor is prevented from colliding with the pump housing, preventing destruction of the pump housing or the rotor itself. During pump operation, the movement of the beating heart or the patient's movements can result in bending moments or forces that, without adjustment of the bending or resistance to the bending moments, could lead to damage to the rotor or pump housing.

[0028] In a variant, the proximal portion of the pump housing has a softer bending resistance compared to the pump receiving portion, and in the region of the proximal portion the flexible shaft is also softer compared to the shaft portion in the pump receiving portion of the housing.

[0029] The stiffness of the pump housing in the proximal section can be influenced, for example, by a helical structure. In one exemplary embodiment, the helical structure creates an elastic region that isolates alternating mechanical loads due to different bending moments. In a variant, the helical structure is arranged symmetrically around the longitudinal axis. The helical structure thus forms a helical region with a spring effect. This spring effect allows for the desired stiffness to be controlled. In particular, the desired stiffness can be set via the angle or spiral course of the helical structure. To ensure the fatigue strength of the pump housing, the maximum local strain at any point on the pump housing is, in a variant, less than 2%.

[0030] In a further embodiment, the pump housing also includes a distal portion distal to the pump receiving portion, and the drive shaft is journaled in a distal bearing in the region of the distal end of the pump housing, and the stiffness of the drive shaft in the region of the distal portion and proximal to the distal portion is adjusted to that of the distal portion so that the conveying element is arranged substantially concentrically in the pump receiving portion when the pump housing is bent. Here, the drive shaft can, for example, be additionally journaled in the region of the distal end of the pump so that the drive shaft is fixed between the proximal and distal bearings. Since the drive shaft has a stiffness in the region of the distal and proximal portions of the pump housing that corresponds to the stiffness of the pump housing in the proximal or distal portion, it is possible to ensure a substantially concentric mounting of the rotor in the pump housing.

[0031] In a further embodiment, the pump housing is shaped so that it is matched to the stiffness of the catheter, for example at the distal or proximal end of the pump region. If the catheter is too stiff, strong deformations will be introduced into the pump housing, but if the catheter is too soft, the position of the housing will not be fixed during operation, and in either case, reliable operation of the rotor in the pump housing cannot be ensured. By matching the stiffness of the pump housing to the stiffness of the catheter, a concentric fit of the rotor in the pump receiving part is now ensured even during operation of the pump.

[0032] To influence the bending resistance of the shaft, a hollow shaft can be used, which is provided with a core, particularly in the region of the pump receiving portion. In addition, the core can extend to the distal and proximal bearings. Also, in the pump of the present invention, the "austenite finish" (A) of the pump housing can be used. f ) The temperature may be lower than 34°C, even lower than 30°C, or even lower than 20°C.

[0033] In the pump arrangement described in this application, different external force effects and alternating bending loads actually act on the drive shaft, the pump housing, the pigtail located distally of the pump housing, and, if applicable, the bearing elements of the catheter or blood pump arrangement. The external force effects and alternating bending loads can be transferred to the catheter, for example, by the inner wall of the heart, due to pulsating blood pressure or flow changes in a heart chamber or blood vessel, such as the left or right ventricle or the aorta, and / or due to changes in body position or posture, particularly due to torso or (leg) movements in the vicinity of the puncture site. The catheter can abut or be supported against the inner wall of the heart (e.g., via what is known as the pigtail tip). Despite these loads, blood can be transported by the proposed catheter and proposed blood pump arrangement for relatively long periods of time, for example, hours, days, or even weeks, even at high rotational speeds of the pump rotor, for example, within the aforementioned rotational speed range, as with the use of the blood pump arrangement described above.

[0034] It is noted that the features specified in each reference example may also be combined with the invention according to claim 1.

[0035] Further aspects will be explained on the basis of the following figures. [Brief explanation of the drawings]

[0036] [Figure 1] FIG. 2 shows a schematic overview of a pump arrangement. [Figure 2a] FIG. 10 shows a variation of the pump housing in which the conveying element is positioned within the pump housing over the drive shaft, with the drive shaft journalled only proximally. [Figure 2b]FIG. 10 shows a variation of the pump housing in which the conveying element is positioned within the pump housing over the drive shaft, with the drive shaft journalled only proximally. [Figure 2c] FIG. 10 shows a variation of the pump housing in which the conveying element is positioned within the pump housing over the drive shaft, with the drive shaft journalled only proximally. [Figure 2d] FIG. 10 shows a variation of the pump housing in which the conveying element is positioned within the pump housing over the drive shaft, with the drive shaft journalled only proximally. [Figure 3a] FIG. 10 shows a modified version of the pump, which comprises a pump housing and a conveying element mounted on a drive shaft, the drive shaft being journalled distally and proximally. [Figure 3b] FIG. 10 shows a modified version of the pump, which comprises a pump housing and a conveying element mounted on a drive shaft, the drive shaft being journalled distally and proximally. [Figure 3c] FIG. 10 shows a modified version of the pump, which comprises a pump housing and a conveying element mounted on a drive shaft, the drive shaft being journalled distally and proximally. [Figure 3d] FIG. 10 shows a modified version of the pump, which comprises a pump housing and a conveying element mounted on a drive shaft, the drive shaft being journalled distally and proximally. [Figure 4a] 10A-10C illustrate an exemplary embodiment of corresponding bending resistance between a pump housing and a drive shaft. [Figure 4b] 10A-10C illustrate an exemplary embodiment of corresponding bending resistance between a pump housing and a drive shaft. [Figure 5a]10A-10C show further embodiments of a pump housing and drive shaft with corresponding bending resistance. [Figure 5b] 10A-10C show further embodiments of a pump housing and drive shaft with corresponding bending resistance. [Figure 6a] 1 illustrates an embodiment of a drive shaft with a core and a rotor. [Figure 6b] 1 illustrates an embodiment of a drive shaft with a core and a rotor. [Figure 7a] 1A-1C illustrate embodiments of a pump housing. [Figure 7b] 1A-1C illustrate embodiments of a pump housing. [Figure 7c] 1A-1C illustrate embodiments of a pump housing. [Figure 8] 10A-10C show an embodiment of the distal end of the pump housing with a catheter mounted therein. [Figure 9] FIG. 10 is an illustration of a pump arrangement with a coordinated combination of pump housing and drive shaft with respect to bend line alignment. DETAILED DESCRIPTION OF THE INVENTION

[0037] A schematic overview of the pump arrangement 1 is provided on the basis of Fig. 1. The pump arrangement 1 comprises a pump housing 2 with a cannula or catheter 3, in which a drive shaft 4 is arranged. A conveying element 5 is driven via the drive shaft 4, a motor 6 being attached to the proximal end of the drive shaft, and the conveying element 5 is located in the region of the pump housing 2. The pump including the drive shaft 4 is now introduced via a port 7, for example through the femoral artery 8 and the aortic arch 9, into the ventricle 10, so that the pump housing is located in the region of the aortic valve. The rotor 5 is shaped so that blood is conveyed from the ventricle into the aorta, i.e., from the distal end of the pump to the proximal end of the pump, in the direction 12.

[0038] The various interactions between the housing, drive shaft, conveying element, and cannula will be explained on the basis of Figures 2a to 2d. In Figures 2a and 2c, the pump housing 20 is shown in longitudinal section in the expanded state (Figure 2a) and in the compressed state (Figure 2c). Corresponding cross sections can be found in Figures 2b and 2d.

[0039] A drive shaft 21 is disposed within the pump housing 20, and a conveying element 22 is positioned on the drive shaft. In this example, the conveying element includes two flexible segments 23 and 24, which are embodied as rotor blades. The pump housing 20 moves from an expanded state to a compressed state by pulling the drive shaft in a pulling direction 25, which is parallel to the longitudinal direction 26 of the pump housing. A cross section is shown in FIG. 2b, with reference to the illustration of the pump housing in the illustration of FIG. 2a. It can be seen that the pump housing 20 is arranged substantially concentrically around the drive shaft 21. In the cross section shown here, struts 27 extending helically as a helical structure can be seen, and the struts 27 can widen in a radial direction 27a from the proximal to the distal portion. The struts extend counterclockwise from the proximal end of pump housing 28 to the distal end of pump housing 29. By comparison, conveying element 22 is also shown, the flexible segments of which convey the fluid. This can also be seen in the plan view of FIG. 2a. As an alternative to the multiple struts, another helical structure can be selected, such as multiple struts that, due to their arrangement, form a helical line or structure.

[0040] When pump housing 20 is retracted into cannula 30 by pulling in pulling direction 25 from the expanded state shown in FIG. 2a to the compressed state, the helical element creates torque 31, which acts in a clockwise direction. It thus opposes the course of the helical strut and attempts to counter the twisting of the helical strut, but no visible change in the housing is discernible. As a result of the torque, segments 23 and 24 are acted upon by torque 31 to wrap around drive shaft 21 in folding direction 32, as shown in FIG. 2d. Thus, when the pump housing is slid longitudinally out of cannula 30 in deployment direction 33, the rotor deploys.

[0041] In the example shown here, the subsequent rotor rotation direction is rotation direction 34, which is opposite to the unfolding direction. In particular, a higher rotation speed may result in a further unfolding of the rotor. However, in other variants, it is possible to select the rotation direction to coincide with the unfolding direction. Here, a higher rotation speed causes an easier folding of the rotor into the folding direction 32.

[0042] In this example, the drive shaft is made of a nickel-cobalt alloy, such as 35NL T® or MP35N®. For example, the cannula is formed from a catheter made of a material known from the prior art, such as silicone or polyurethane. The pump housing can be made, for example, from Nitinol. Here, in this example, the A of the pump housing f The temperature is approximately 15°C, f The temperature is such that it is below room temperature. This has advantages in terms of the stability of the pump housing. In the following example, the drive shaft is simply journaled by the proximal bearing sleeve 35. Regarding the materials used for the rotor, for example, the materials described in U.S. Patent Application No. 13 / 261,565 can be used.

[0043] In the example shown in FIG. 2, the spirally arranged struts extend both into the proximal portion of the pump housing and into the region of the pump receiving portion, the proximal portion of the pump housing being located proximal to the conveying element 22 and the region of the pump receiving portion being located within the region of the conveying element 22.

[0044] Variations of the pump housing, conveying element and drive shaft combination are shown by way of example in Figures 3a to 3d.

[0045] The differences between the embodiment of Figure 2 and the embodiment of Figure 3 are, inter alia, that the drive shaft in the embodiment of Figure 3 is journalled both in the distal end and in the region of the proximal end of the pump housing.

[0046] The pump housing 40 shown in FIG. 3a includes a pump-receiving portion 41, a portion 42 located distally of the pump-receiving portion, and a distal end portion 43 located distally of the distal portion. The pump housing also includes a proximal portion 44 located proximal to the pump-receiving portion and an end portion 45 located proximal to the proximal portion. The pump housing 40 has a helical strut 46 in the proximal portion 44 and the distal portion 42, as shown by way of example in FIG. 3b. Here, the strut extends counterclockwise from the proximal end of the pump to the distal end of the pump. A cannula 47 is additionally shown in FIG. 3a, enveloping the drive shaft 48 as it passes through the aortic arch and the body's blood vessels. A rotor 49 is additionally disposed on the drive shaft in the region of the pump-receiving portion 41 of the housing and serves to transport blood from the distal end to the proximal end. 3b, it can be seen that in proximal portion 44, helical struts 46 extend counterclockwise from the inside (i.e., from the distal end of end portion 45) to the outside (i.e., toward the proximal end of portion 41), while helical struts 50 in distal portion 42 extend clockwise from the outside to the inside. As a result, when distal end portion 43 and proximal end portion 45 are grasped and pulled in opposite directions, a clockwise-extending torque acts on pump-receiving portion 41. This mechanism is also effective when the pump housing is retracted into the cannula. In a manner corresponding to FIG. 2a, the pump in FIG. 3a is shown in an inflated state. Here, when a tensile force 53 directed opposite to the longitudinal direction 52 becomes effective, the diameter of the pump housing is reduced in portions 41, 42, and 44, while simultaneously inducing a clockwise-acting torque 51. For the reduction in diameter during collapse, the pump housing 40 interacts with the conveying element 49 or with the flexible segments 54 and 55 of the conveying element 49. Due to their shape and their orientation, the flexible segments 54 and 55 have a folding direction 56 in the direction of torque.Thus, flexible segments 54 and 55 are wrapped around drive shaft 48 in a folding direction 56. Now, when the pump housing is moved from the compressed configuration of FIG. 3c to the expanded configuration of FIG. 3a, the rotor unfolds in a deployment direction 57, which coincides with the spiral direction 58 of the helical struts. In this example, rotor 48 then rotates in a direction 59 to guide blood from the distal end to the proximal end of the pump.

[0047] The embodiment shown in FIG. 3 corresponds to a "candy wrapper" because the spiral defining the course of the helical strut rotates in opposite directions at the distal and proximal portions. As a result, torque is introduced into the pump-receiving portion 41 only at the distal portion 42 and the proximal portion 44, but torque acting in the distal end portion 43 and the proximal end portion 45 is reduced. Because bearings (not shown) for the drive shaft 48 are located at the distal and proximal end portions, torque from the pump housing is transmitted to the drive shaft as needed when the pump housing 40 is moved from an expanded state to a compressed state.

[0048] The corresponding bending resistance of the pump housing and the corresponding bending resistance of the shaft will be discussed based on Figures 4a and 4b, and also based on Figures 5a and 5b.

[0049] A pump configuration corresponding to that of FIG. 3 is shown in FIGS. 4a and 4b. In particular, pump housing 40 includes sections 41 to 45, as described with reference to FIG. 3, and drive shaft 48, which is held proximally in first bearing 60 and in distal bearing 61. Helical struts 46 and 50 are disposed in distal section 42 and proximal section 44, respectively. Now, as shown in FIG. 4b, if a bending moment is applied to pump housing 40, helical struts 46 and 50, due to their symmetrical arrangement around the drive shaft, cause the pump housing to bend, which corresponds to a corresponding bending of the drive shaft in distal section 42 and proximal section 44, respectively. Here, the shaft can be softer, for example, in the aforementioned region than in the region of pump-receiving section 41. The stiffening in the pump-receiving section is additionally reinforced by the rotor itself or a rotor hub. As a result, as can be seen in FIG. 4b, the conveying element 49 remains substantially concentric within the pump receiving portion even under bending load. For example, due to the thickness of the struts, the selected angle of the helical struts, and the number and arrangement of the struts, the corresponding bending moment can be adapted to the stiffness of the shaft in the corresponding area. Here, the bending moment is the sum of the products of the occurring forces and the corresponding force arms over all acting forces, where the force arms are the distances from the bearing points. For example, a point within the proximal bearing area can be selected as the bearing point.

[0050] 5a and 5b show a corresponding situation, in which the pump arrangement substantially corresponds to that of FIG. 2. However, the pump housing 20′ in this case has a rigid pump receiving portion and a distal portion 201 disposed distally of the pump receiving portion 200, the distal portion having a helical structure 27. The helical structure 27 can be generated due to a conductor-like arrangement of various struts and their connection or by segmental rotation of the strut structure, and the helical structure 27 is configured so that the stiffness of the pump housing at the distal portion 201 is softer than that at the pump receiving portion 202. Therefore, bending moments acting on the pigtail 36 can be absorbed not only by the distal transition structure 37 but also by the distal portion, which can be constructed, for example, from four struts. Therefore, bending moment 38 (FIG. 5b) does not act on the pump receiving portion, and the drive shaft is positioned substantially concentrically within the pump receiving portion even when a bending moment is applied. Pump receiving portion 200 is stiffer, and measures to increase its bending resistance will be described in one of the exemplary embodiments that follow.

[0051] The pump housing may also optionally include a proximal portion 202 having a helical structure 27 to compensate for effective bending moments and to facilitate compression of the pump housing.

[0052] Further details of various aspects of the present invention will be discussed with reference to Figures 6a and 6b. The shaft structure 70 includes a drive shaft 71 with a distal end 72, a conveying element 73, and a proximal end 74, which can be coupled to a motor, for example, using a coupling element. In the region of the conveying element 73, the drive shaft 71 is reinforced by a core 75, which extends between the distal end 72 and a region proximal to the conveying element 73. The conveying element 73 includes two flexible segments 76 and 77, which cause fluid to be conveyed from the distal end to the proximal end, with the direction of rotation of the conveying element being clockwise when considered from the proximal end to the distal end. Figure 6b illustrates a cross section of the rotor 73 from the proximal end to the distal end. Here, the configuration of the flexible segments 76 and 77 can be seen in more detail. The folding direction of the rotor when the pump housing (not shown) is retracted into the cannula is clockwise, i.e., points 78 and 79 are transported radially inward and in a clockwise direction. Thus, the rotor unfolds when the delivery element is slid out of the catheter in a counterclockwise direction. Therefore, in a variant, the illustrated delivery element or shaft arrangement 70 is provided with a housing that is shaped so that it creates a torque in a clockwise direction when the pump housing is moved from an expanded state to a compressed state.

[0053] Here, the core 75 can create an improved stiffness compared to other regions of the hollow drive shaft 71. Here, the core can have a different stiffness from its distal end to its proximal end, such that, for example, the stiffness proximal and / or distal to the conveying elements is reduced compared to the stiffness of the core in the region of the conveying elements. However, a corresponding stiffness of the shaft in the region of the conveying elements can also be achieved by a corresponding design (or adjustment) of the rotor hub.

[0054] Further details of the pump housing will be described with reference to FIGS. 7a to 7c. In FIG. 7a, the pump housing shown in FIG. 7b is cut along an imaginary separation line, unrolled, and pressed flat. However, in one embodiment, the pump housing is first cut, for example, by a laser, as shown in FIG. 7a. The cutting can be performed in a tube mold. The configuration shown in FIG. 7b is then achieved by an annealing process in the mold. The pump housing 80, similarly unrolled in FIG. 7a, has a proximal end portion 83 at its proximal end 81, which extends to the helical element 82. Here, short regions before and after the helical struts 82 define a proximal portion 84. The pump-receiving portion 85 has a lattice design, in which the interconnected struts have contact points with each other. Like the proximal portion 84, the distal portion 86 has helical struts 87, which are obviously oriented to the struts 82 in terms of their spiral direction. At the distal end is disposed a distal end portion 88, in the region of which, for example, a drive shaft may be journaled within a catheter or pigtail. The angle at which the helical element 82 extends from the proximal end portion to the pump receiving portion can be, for example, between 20° and 40°. Similarly, the angle of the struts 87 can also be between 20° and 40° (but in the opposite direction).

[0055] In these embodiments, the two angles are oriented in opposite directions, as shown in FIG. 7. Now, when the pump housing 80 is joined as shown above, the expanded pump housing shown in FIG. 7b is produced. It can be clearly seen that there is an increase in the inner diameter from the proximal end to the distal end, and vice versa, in the regions of the proximal and distal portions 84 and 86, respectively. Here, the pump-receiving portion 85 has the largest inner diameter to achieve high efficiency in transporting fluid. A cross-section of the pump housing 80, considered from the proximal end to the distal end, is shown in FIG. 7c, where it can be clearly seen that the struts 82 run in a counterclockwise direction. Also shown are the support struts 89, which transition into the grid struts 85a of the pump-receiving portion.

[0056] The distal end portion 88 of the pump housing 80 is shown in FIG. 8. Here, a catheter 90 is inserted into the distal end portion 88 and includes, among other things, a bearing sleeve 91 in which the distal end of the shaft arrangement 70 is journaled. Here, the bearing can be made of, for example, ceramic, while the shaft can be constructed of the materials previously described.

[0057] 9 shows a longitudinal section through a pump arrangement 100, which comprises a pump housing 101, a drive shaft 102 and a rotor 103 arranged on the drive shaft. Also shown is an outflow tube 104. In the distal end region 110 of the pump housing, this is connected to a catheter formed as a pigtail (not shown). Here, the mounting of the drive shaft 102 in the distal end portion substantially corresponds to the mounting described with reference to FIG. 8.

[0058] In the region of the proximal end portion 111, the drive shaft proximal bearing / support 112 is arranged, which includes both a radial and an axial bearing. This bearing is described in more detail in European patent application EP 2 868 289 A1 (published under EP 2 868 289 A1, having internal file reference 137 EP 2457), which is incorporated herein in its entirety.

[0059] Disposed between the distal and proximal end portions of pump housing 101 are distal portion 112, pump-receiving portion 113, and proximal portion 114. Both distal and proximal portions have helical struts 115 and 116, respectively, which transition toward the pump-receiving portion into support struts 117 and 118, respectively. These support struts further divide into pump-receiving portion struts 119. A plastic film 120, which in the exemplary embodiment is made of polyurethane, is positioned inside the pump-receiving portion. This film improves the transport effect of rotor 103.

[0060] The rotor 103 includes two flexible rotor blades 130 and 131 fastened to a hub 132. In some exemplary embodiments, the rotor is a single workpiece made from a plastic such as polyurethane, e.g., biresin, or silicone or Pebax. For clarity, the rotor 103 is not shown in the cross-sectional illustrations.

[0061] The rotor 103 is disposed on a drive shaft 102, which is formed as a hollow shaft. For further details, reference is made to application PMP Ref. 137EP 2457. The hollow shaft is strengthened by a core 105 between the distal and proximal bearings / bearings.

[0062] When aligning the bending line of the pump housing with the bending line of the drive shaft, it must be ensured that, if bending moment 140 (or 141 or 142) acts on the pump housing, rotor 103 remains substantially concentric within pump receiving portion 113 or that the rotor does not contact the inner surface of pump receiving portion 113. As a first measure, the stiffness of the pump receiving portion is stiffer in this exemplary embodiment than that of the distal or proximal portions. For simplicity, the stiffness of the distal and proximal portions are selected symmetrically in the exemplary embodiment shown. The possibility of influencing the stiffness of pump receiving portion 113 is configured by the density and number of struts 119 in relation to the considered housing diameter. In this example, distal portion 112 and proximal portion 114 each have 10 helical struts, which transition to 20 support struts 117 and 118, respectively, toward the pump receiving portion. Support struts 117 and 118 again divide into 40 struts 119, with the number of struts in the pump-receiving region now being four times greater. In other exemplary embodiments, this factor can vary between 0.9 and 20. The stiffness in the pump-receiving portion is thus greater than that of the distal or proximal regions.

[0063] A further possibility for matching (here, making softer) the stiffness of the distal and proximal portions compared to the pump-receiving portion consists of changing the geometric dimensions of the struts 115-119. In this example, struts 115 and 116 are two to three times thicker than strut 119. Due to the factor of four in the strut number ratio, the proximal and distal portions would otherwise be too soft in some exemplary embodiments if struts 115-119 were of equal thickness.

[0064] A further possibility for matching the bending resistance in the proximal and distal regions is provided by the choice of the bending angle of the helical strut. In this example, the helical strut wraps around an angle of approximately 30° from the distal end to the proximal end of the proximal or distal portion. However, the range may also lie between 5° and 90°.

[0065] A further possibility is to vary the length of the proximal and distal portions. In a method for matching the bending resistance of a pump housing, the shaft construction is first measured, then the above-mentioned parameters of the different portions of the pump housing are calculated, and then a suitable pump housing is created.

[0066] The drive shaft's bending resistance can be matched by the hollow shaft stiffness, the core stiffness, and the rotor stiffness. In some exemplary embodiments, the hollow shaft may be subjected to strong bending, for example, in the aortic arch, so the hollow shaft must have a bending resistance that allows for this type of bending while also having strength to operate at high rotational speeds for as long as possible. Thus, in some exemplary embodiments, the hollow shaft's bending resistance is primarily matched to the requirements of the hollow shaft between the motor and the bearing. However, the core stiffness can also be matched to match the bend line of the drive shaft to the bending resistance of the pump housing between the proximal and distal bearings.

[0067] Moreover, the material selection and geometry of rotor 103 causes the drive shaft to be stiffened in the region of the pump receiving portion 113, such that the drive shaft construction with rotor is softer in the regions of the distal and proximal portions than in the region of the pump receiving portion. Further adaptation possibilities will become clear to those skilled in the art from the comments made herein.

[0068] In a further exemplary embodiment, the pump housing has a helical structure resulting from multiple interconnected struts. Due to the selection of the connection point between two struts, the struts extend upward or downward at an incline, creating a helical structure oriented in one direction. By varying the thickness, number, and length of the structures, as well as the angle of the included structures, the stiffness of the structure can be matched to that of the drive shaft.

[0069] Further embodiments and variations of the invention will emerge from the combinations specified herein and from combinations that will be apparent to those skilled in the art.

Claims

1. A blood pump (1) having a proximal end and a distal end and a pump housing disposed therebetween, a drive shaft disposed longitudinally inside the pump housing, a conveying element disposed on the drive shaft, and a cannula, the pump housing includes a pump receiving portion, a proximal portion disposed proximally of the pump receiving portion, and a distal portion disposed distally of the pump receiving portion, and is configured to be moved from an expanded state to a compressed state along a radial direction when moved into the cannula; the proximal portion and the distal portion each include a plurality of helical structures extending helically along and around the longitudinal axis in the expanded state; each helical structure of the proximal portion is wound in a first direction when considered from the proximal end to the distal end; each of the helical structures of the distal portion being wound in a direction opposite to the first direction; A blood pump characterized by:

2. 2. The blood pump of claim 1, the conveying element includes at least one foldable segment; A blood pump, wherein the deployment direction of the at least one foldable segment extends in the first direction during deployment.

3. 2. The blood pump of claim 1, the conveying element includes at least one foldable segment; A blood pump, characterized in that the deployment direction of the at least one foldable segment extends in a direction opposite to the first direction during deployment.

4. 4. The blood pump according to claim 1, A blood pump, characterized in that the pump housing is made from a shape memory material.

5. 5. A blood pump according to claim 1, 1. A blood pump comprising: a proximal portion of the pump housing having an inner diameter that, in the expanded state of the pump housing, decreases from a diameter of the pump receiving portion toward the proximal end of the proximal portion.

6. 2. The blood pump of claim 1, A blood pump characterized in that a plurality of the spiral structures are arranged in the pump receiving portion.

7. 6. The blood pump according to claim 5, 1. A blood pump comprising: a pump housing having a distal end portion, the distal end portion having an inner diameter that is reduced from a diameter of the pump receiving portion toward the distal end of the distal end portion when the pump housing is in the expanded state.

8. 8. A blood pump according to any one of claims 1 to 7, A blood pump, characterized in that the drive shaft is journalled at least in the region of the proximal end of the pump housing.

9. 9. The blood pump of claim 8, 10. A blood pump, characterized in that the drive shaft is additionally journalled in the region of the distal end of the pump housing.

10. 10. A blood pump according to any one of claims 1 to 9, A blood pump characterized in that each of the plurality of spiral structures includes a spiral strut.

11. 2. The blood pump of claim 1, the conveying element includes at least one foldable segment; The at least one foldable segment is configured such that a rotational direction of the conveying element causes fluid to be conveyed from the distal end to the proximal end.

12. 4. The blood pump according to claim 2 or 3, The at least one foldable segment is configured such that a rotational direction of the conveying element causes fluid to be conveyed from the distal end to the proximal end.

13. 13. A blood pump according to claim 11 or 12, When the pump housing is moved from the compressed state to the expanded state, the deployment direction of the at least one foldable segment is oriented opposite to the rotation direction.

14. 14. A blood pump according to any one of claims 1 to 13, characterized in that the drive shaft is a hollow shaft including a core in the region of the pump housing.

15. 15. A blood pump according to any one of claims 1 to 14, wherein the pump housing has an "austenite finish" (A ｆ ) A blood pump characterized in that the temperature is lower than 34°C.

16. 16. The blood pump of claim 15, wherein the pump housing has an "austenite finish" (A ｆ ) A blood pump characterized in that the temperature is lower than 30°C.

17. 17. The blood pump of claim 16, wherein the pump housing has an "austenite finish" (A ｆ ) A blood pump characterized in that the temperature is lower than 20°C.

Images