Pump section for a blood pump and blood pump

Abstract

A pump section (10) for a blood pump (100) is provided. The pump section (10) comprises a pump housing (14), a pump element (16), an outflow tube (18) and a stabilizing device (20). The stabilizing device (20) is located downstream of a blood flow outlet (28) of the pump housing (14) and the stabilizing device (20) is configured to stabilize the pump section (10) by influencing at least one flow parameter of a blood flow generated by the pump element (16). The at least one flow parameter comprises a differential pressure of an interior of the outflow tube (18) to an exterior of the outflow tube (18) and / or a resulting blood flow direction D2.

Description

[0001] PUMP SECTION FOR A BLOOD PUMP AND BLOOD PUMP

[0002] The present disclosure relates to the field of medical technology. Specifically, the present disclosure relates to a pump section for a blood pump and a blood pump.

[0003] BACKGROUND OF THE DISCLOSURE

[0004] Cardiac assist devices, such as blood pumps, for assisting a heart function of a patient are known from the prior art. Such blood pumps may comprise an implantable blood pump section which may, for example, be inserted into a ventricle of the heart by minimally invasive means. Further, the blood pump may comprise an external (or extracorporeal) motor to drive a pump element of the pump section to generate a blood flow to unload blood from the left ventricle into the aorta, for example. The motor may be connected with the pump section via a transcutaneous and flexible drive shaft which may be rotatably mounted inside a transcutaneous catheter. The implantable components of the device may be inserted through the femoral artery via a puncture site in a patient’s groin, for example. Of course, the implantable components of the device may also be inserted via the axillary artery, for example.

[0005] The pump section of such a blood pump may have a pump housing having a blood flow inlet and a blood flow outlet, a pump element at least partially disposed in the pump housing and an outflow tube. The pump element may be configured to generate a blood flow between the blood flow inlet and the blood flow outlet of the pump housing. The outflow tube may surround the blood flow outlet of the pump housing to channel and guide the blood flow generated by the pump element, for example, from the left ventricle, in which the pump housing with the pump element may be positioned, through the aortic valve into the aorta. For this purpose, the outflow tube may have an elongated configuration extending from a distal end portion to a proximal end portion along a longitudinal extension direction of the outflow tube. The distal end portion may be connected to the pump housing. Furthermore, the known outflow tubes have outlet openings in their tube skin, i.e. outlet holes, through which the blood flow generated by the pump element will eventually exit the pump section at the intended location (in the aorta after the aortic valve, for example).

[0006] To minimize the necessary invasive procedure, the pump housing, the pump element and the outflow tube of the pump section may have a flexible configuration. That is, they may be collapsible and expandable. For that purpose, the outflow tube is usually a thin polyurethane tube, for example, which may be folded into an introducer sheath, which may be used for introducing the pump section into the patient. With such a flexible configuration of the outflow tube, once the introducer sheath is removed and once the pump element starts generating a blood flow, this blood flow will “inflate” the outflow tube to its intended and operational form. However, it has been observed with this kind of configuration of the pump section that fluttering of the outflow tube may occur due to different blood flow velocities inside and outside the outflow tube over a cardiac cycle. The fluttering of the outflow tube is dependent from various parameters such as rotational speed of the pump element, afterload, preload, cardiac cycle, condition of the aortic valve, positioning of the pump section and / or the outflow tube in the ventricle and / or the blood vessel, and the like. Such fluttering of the outflow tube may cause irritation of the surrounding tissue of the patient resulting in unwanted mechanical stresses on the tissue. For example, irritations of the endocardium may lead to ectopic beats. In addition, it was found that with such a flexible configuration of the outflow tube, the stability of the positioning of the entire pump section in the patient may be reduced compared to blood pumps with a rigid suction tube.

[0007] Thus, it is an object of the present disclosure to provide a pump section for a blood pump which reduces fluttering of the outflow tube and which provides improved positioning stability of the pump section.

[0008] SUMMARY OF THE DISCLOSURE

[0009] According to a first aspect, a pump section for a blood pump is provided. The pump section comprises a pump housing, a pump element, an outflow tube and a stabilizing device. The pump housing has a blood flow inlet and a blood flow outlet. The pump element is at least partially disposed in the pump housing, wherein the pump element is configured to generate a blood flow between the blood flow inlet and the blood flow outlet. The outflow tube surrounds the blood flow outlet of the pump housing. The outflow tube is configured to channel the blood flow generated by the pump element. The outflow tube has an outlet for the blood flow. The stabilizing device is located downstream of the blood flow outlet of the pump housing. The stabilizing device is configured to stabilize the pump section by influencing at least one flow parameter of the blood flow generated by the pump element.

[0010] In particular, downstream of the blood flow outlet is to be understood with respect to the flow direction of the blood flow generated by the pump element. The at least one flow parameter may be any parameter associated with the blood flow such as pressure, volume flow, direction or the like. By influencing the at least one flow parameter downstream of the blood flow outlet, the stabilizing device serves to reduce fluttering of the outflow tube and to improve the positioning stability of the pump section.

[0011] Preferably, the at least one flow parameter comprises a differential pressure between an interior of the outflow tube and an exterior of the outflow tube. The stabilizing device may be configured so that the differential pressure is at least a minimum differential pressure, wherein the minimum differential pressure is preferably 5 mmHg, more preferably 10 mmHg. Preferably, the stabilizing device comprises a throttle for the blood flow generated by the pump element. Further preferably, the stabilizing device is configured so that the differential pressure is at least the minimum differential pressure during the systole.

[0012] The differential pressure is calculated by subtracting the external pressure of the outflow tube from the internal pressure of the outflow tube. That is, the internal pressure of the outflow tube is preferably at least 5 mmHg, preferably at least 10 mmHg, higher than the external pressure acting on the outflow tube. That is, the differential pressure is at least 5 mmHg especially during the systole. In this respect, the stabilizing device may comprise a throttle to cause the minimum differential pressure. The throttle may be formed by the outlet of the outflow tube and / or by a throttle ring attached to the outflow tube forming the throttle within the outflow tube. The throttle ring may be disposed around an outer surface of the outflow tube. The throttle ring may have a diameter that is smaller than a diameter of the outflow tube at the position where the throttle ring is positioned. Thus, the throttle ring may locally constrict the outflow tube forming the throttle for the blood flow generated by the pump element flowing through the outflow tube. By influencing the differential pressure between the interior of the outflow tube and the exterior of the outflow tube to be at least the minimum differential pressure, the fluttering effect at the outlet of the outflow tube is reliably reduced.

[0013] Preferably, the outflow tube has a distal end portion connected to the pump housing and a proximal end portion. The outflow tube may have an elongated configuration extending from the distal end portion to the proximal end portion along a longitudinal extension direction of the outflow tube. The at least one flow parameter may comprise a resulting blood flow direction at the outlet of the outflow tube. The stabilizing device may be configured so that an axial portion of the resulting blood flow direction is directed away from the distal end portion along the longitudinal extension direction of the outflow tube, preferably the longitudinal extension direction of the proximal end portion of the outflow tube. Further preferably, the stabilizing device is configured so that the resulting blood flow direction is substantially parallel to the longitudinal extension direction of the proximal end portion of outflow tube.

[0014] Preferably, the stabilizing device comprises the outlet of the outflow tube. The outlet of the outflow tube may be configured so that the differential pressure is at least a minimum differential pressure, preferably during the systole, and so that the axial portion of the resulting blood flow direction is directed away from the distal end portion along the longitudinal extension direction of the outflow tube.

[0015] That is, the blood flow vector at the outlet has an axial portion parallel to the longitudinal extension direction of the outflow tube and a radial portion perpendicular to the longitudinal extension direction of the outflow tube. The vectorial addition of the two perpendicular portions results in the resulting blood flow direction. The resulting blood flow direction being substantially parallel to the longitudinal extension direction means that the axial portion of the blood flow vector is larger than the radial portion of the blood flow vector. As the axial portion of the resulting blood flow direction is directed away from the distal end portion of the outflow tube along the longitudinal extension direction of the outflow tube, a thrust on the pump section is generated in the opposite direction of the blood flow at the outlet. This thrust may also be referred to as an “axial thrust” on the pump section. By generating this axial thrust, fluttering of the outflow tube is reduced and the positioning stability of the pump section is improved.

[0016] Specifically, in case the pump section is used for generating a blood flow from the left ventricle to the aorta, the whole pump section will experience a force in a direction from the left ventricle to the aorta during the systole. This force on the pump section may lead to movement of the pump section within the left ventricle or even to the pump housing with the pump element being ejected through the aortic valve during systole and reentering during diastole with potential periodic touch of the endothelium (so called “jack-hammering”). The axial thrust generated by the outlet in the opposite direction of the blood flow counters such movements of the pump section leading to an improved positional stability of the pump section.

[0017] Preferably, the outlet of the outflow tube is formed in or by the proximal end portion of the outflow tube. Thus, the thrust generated by the outlet takes effect over the entire longitudinal extension of the outflow tube further assisting in reduced fluttering and improved positional stability. Additionally, the outlet is suitably positioned to discharge the blood flow channeled by the outflow tube at its intended location (in the aorta after the aortic valve, for example).

[0018] In one embodiment, the pump section may further comprise a catheter connected to the pump housing, wherein the catheter has a circumferential surface. The proximal end portion of the outflow tube may comprise a tapered portion tapered towards the catheter and an attachment portion attached to the circumferential surface of the catheter. The tapered portion may comprise at least one outlet opening, preferably at least one outlet hole. The outlet of the outflow tube may be formed by the at least one outlet opening, preferably by multiple outlet openings evenly distributed in a circumferential direction around the tapered portion. The shape of the at least one outlet opening may be a circle, an elongated circle, an arch, a semi-circle, an elongated semi-circle, an oval, a rhombus, a triangle or a drop shape. The at least one outlet opening preferably has rounded corners. The attachment portion may be attached to the circumferential surface of the catheter by bonding, for example by an adhesive or by thermal bonding. The tapered portion may have a tapering angle towards the catheter of at least 40 degrees, preferably of at least 70 degrees, further preferably of at least 85 degrees.

[0019] Forming the at least one outlet opening in the tapered portion facilitates directing the blood flow substantially in parallel to the longitudinal extension direction of the outflow tube rather than in a radial direction of the outflow tube, for example. The steeper the tapered portion tapers towards the catheter, the larger the axial portion of the blood flow vector becomes. Thus, the axial thrust on the pump section generated by the outlet is further increased and the positional stability of the pump section is further improved.

[0020] The at least one outlet opening may extend up to or into the attachment portion. That is, the at least one outlet opening may extend to the circumferential surface of the catheter, to which the attachment portion is attached. Thus, the risk of pockets in which blood clots may form is reduced.

[0021] The outflow tube may comprise an intermediate portion connecting the distal end portion and the proximal end portion and the at least one outlet opening may be formed only in the proximal end portion. That is, the at least one outlet opening does not extend over the tapered portion into the intermediate portion in a direction towards the distal end of the outflow tube. This helps reduce the radial portion of the blood flow vector at the at least one outlet opening.

[0022] Preferably, the at least one outlet opening extends into a mounting-slit in the attachment portion. The mounting-slit in the attachment portion is used during assembly of the pump section to fold the outflow tube over the already assembled pump housing. Extending the at least one outlet opening into the mounting-slit reduces production steps when forming the at least one outlet opening. If multiple outlet openings are provided, it may be sufficient that one of the multiple outlet openings extends into a mounting-slit in the attachment portion. It is also conceivable that each outlet opening extends into a mounting-slit in the attachment portion.

[0023] Alternatively or additionally, the pump section may further comprise a catheter connected to the pump housing, wherein the catheter has a circumferential surface. The catheter may comprise at least one attachment strut, preferably multiple attachment struts evenly distributed around the circumferential surface of the catheter. The proximal end portion of the outflow tube may comprise an attachment portion attached to the at least one attachment strut. The outlet of the outflow tube may be formed by at least one outlet gap, preferably multiple outlet gaps, formed between the proximal end portion of the outflow tube and the catheter. Additionally, the proximal end portion may comprise the tapered portion and the outlet may comprise at least one outlet opening in the tapered portion as described above.

[0024] By providing the at least one outlet gap between the proximal end portion of the outflow tube and the catheter, the blood flow is directed in parallel to the longitudinal extension direction of the outflow tube and the blood flow vector has substantially no radial portion. Thus, the axial thrust created by the blood flow improves the positional stability of the pump section and fluttering of the outflow tube is reduced.

[0025] The at least one attachment strut may be formed integrally with the catheter on the circumferential surface of the catheter. Alternatively, the catheter may comprise an attachment ring having the at least one attachment strut, wherein the attachment ring is connected to the circumferential surface of the catheter. The connection between the attachment ring and the catheter may be formed by bonding, for example by an adhesive or by thermal bonding. The at least one attachment strut may be a collapsible spring structure, preferably made from Nitinol. Thus, the at least one attachment strut may be collapsible during insertion of the pump section into the patient and during removal from the patient and at the same time ensure the at least one outlet gap to be open during use within the patient.

[0026] Alternatively or additionally, the pump section may further comprise a catheter connected to the pump housing, wherein the catheter has a circumferential surface. The proximal end portion of the outflow tube may comprise at least one attachment strip, preferably multiple attachment strips, attached to the circumferential surface of the catheter. The proximal end portion of the outflow tube may further comprise at least one outlet pocket with an outlet opening, preferably multiple outlet pockets. The at least one outlet pocket may be formed in that the at least one attachment strip is attached to the circumferential surface of the catheter. The outlet of the outflow tube may be formed by the at least one outlet pocket, wherein preferably multiple outlet pockets form a cloverleaf shape. With this configuration of the outlet, the blood flow vector at the outlet basically only has an axial portion resulting in an improved axial thrust on the pump section and reduced fluttering of the outflow tube.

[0027] Specifically, the outflow tube extends into the at least one attachment strip at its proximal end portion. In this case, the proximal end portion does not taper towards the catheter. By attaching the at least one attachment strip to the catheter, a longitudinal constriction in the longitudinal extension direction of the outflow tube is resulting in the at least one outlet pocket. Preferably, three or four attachment strips may be provided forming three or four longitudinal constrictions and three or four outlet pockets resulting in a three-leaf cloverleaf shape or in a four-leaf cloverleaf shape.

[0028] Alternatively or additionally, the outflow tube may comprise at least one guide tube, preferably multiple guide tubes, in fluid connection with the outflow tube. The at least one guide tube may extend substantially in parallel to the longitudinal extension direction of the outflow tube. The outlet of the outflow tube may be formed by the at least one guide tube. The guide tube may therefore end in an outflow opening oriented so that the blood flow exits the guide tube substantially in parallel to the longitudinal extension direction of the outflow tube. Specifically, at least one guide tube may be disposed radially outside of the outflow tube.

[0029] In particular, the outflow tube may comprise an intermediate portion connecting the distal end portion and the proximal end portion, wherein the intermediate portion may comprise multiple openings evenly distributed in a circumferential direction around the intermediate portion. One guide tube may be connected to each opening in the intermediate portion. The fluid connection between the outflow tube and the guide tube may be formed by bonding, for example by an adhesive or by thermal bonding, of one end of the guide tube to an outer surface of the outflow tube around the opening in the intermediate portion. An outer surface of the at least one guide tube may at least partially be bonded to an outer surface of the outflow tube, for example by an adhesive or by thermal bonding. Additionally or alternatively, the pump section may further comprise a positioning ring surrounding the at least one guide tube and the outflow tube. In case the at least one guide tube is disposed outside of the outflow tube, the positioning ring may serve to hold the at least one guide tube in place and to ensure that the outflow opening of the guide tube is oriented so that the blood flow exits the guide tube substantially in parallel to the longitudinal extension direction of the outflow tube.

[0030] Preferably, the outlet has a total outlet area of between 20 mm2and 70 mm2, preferably between 30 mm2and 50 mm2, further preferably between 33 mm2and 35 mm2. The total outlet area is calculated by adding the area of all openings through which the blood flow generated by the pump element exits the outflow tube. That is, the total outlet area may comprise the total area of all outlet openings in the outflow tube and / or the total area of all outlet gaps and / or the total area of all outflow openings of the guide tubes. By providing a total outlet area of equal to or less than 70 mm2, the outlet forms a throttle for the blood flow generated by the pump element exiting the outflow tube. Thus, the desired minimum differential pressure of preferably at least 5 mmHg between the interior of the outflow tube and the exterior of the outflow tube is ensured. Additionally, the outlet then functions as a nozzle for the blood flow exiting the outflow tube resulting in the desired axial thrust. Thus, the fluttering of the outflow tube is reduced and the positioning stability of the pump section is improved.

[0031] Preferably, the outflow tube is composed of a biocompatible material, such as a suitable polymer, such as polyurethane, polyamide, nylon, or silicone. Preferably, the outflow tube is made from polyurethan (PU) or polytetrafluoroethylene (PTFE).

[0032] Preferably, the outflow tube has a connection angle with respect to the pump housing at the distal end portion of between 0.5 and 4 degrees, preferably between 1 and 2 degrees, further preferably of about 1 .5 degrees. This further helps in directing the blood flow exiting the pump section housing in a manner beneficial to creating an axial thrust and thus improving positional stability of the pump section.

[0033] According to a second aspect, a blood pump, in particular an intravascular blood pump, comprises a pump section as described above.

[0034] BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The foregoing summary as well as the following detailed description of preferred embodiments will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present disclosure, reference is made to the drawings. The accompanying drawings are not drawn to scale. In the drawings, identical or corresponding components illustrated in various figures are represented by the same reference numeral. For purposes of clarity, not every component may be labeled in every drawing. The scope of the disclosure is not limited to the specific embodiments disclosed in the drawings.

[0036] In the drawings:

[0037] Fig. 1 is a schematic representation of an intravascular blood pump, which is positioned within the left ventricle of the heart;

[0038] Fig. 2 is an illustration of a part of a pump section of the blood pump of Fig. 1 ;

[0039] Fig. 3 is a schematic illustration of a proximal end portion of an outflow tube in accordance with a first embodiment;

[0040] Fig. 4 is a schematic side view of the proximal end portion of the outflow tube illustrated in Fig. 3;

[0041] Fig. 5 is another schematic side view of the proximal end portion of the outflow tube illustrated in

[0042] Fig. 3;

[0043] Fig. 6 is a schematic partial side view of an outflow tube in accordance with a second embodiment;

[0044] Fig. 7 is a schematic partial side view of an outflow tube in accordance with a third embodiment;

[0045] Fig. 8 is a schematic sectional view of the outflow tube of Fig. 7 along the line XIII - XIII;

[0046] Fig. 9 is a schematic perspective view of an outflow tube in accordance with a fourth embodiment;

[0047] Fig. 10 is a schematic side view of an outflow tube in accordance with a fifth embodiment; and

[0048] Fig. 11 is a schematic perspective view of a proximal end portion of an outflow tube in accordance with a sixth embodiment.

[0049] DETAILED DESCRIPTION

[0050] Fig. 1 shows the use of a blood pump 100 for supporting a patient’s heart H. The blood pump 100 in this example is an intravascular blood pump 100. In this particular example, the intravascular blood pump 100 supports a left ventricle LV of the patient’s heart H. As schematically shown, the intravascular blood pump 100 comprises a pump section 10 partially disposed within the left ventricle LV of the patient’s heart H and a motor 102, which is preferably placed outside the patient’s body.

[0051] The pump section 10 comprises a catheter 12, a pump housing 14, a pump element 16, an outflow tube 18 and a stabilizing device 20, which will be explained in more detail below. The catheter 12 connects the motor 102 with the pump housing 14 of the pump section 10.

[0052] The intravascular blood pump 100 may be placed inside the patient’s heart H using a percutaneous, transluminal technique. For example, the intravascular blood pump 100 may be introduced through a femoral artery. However, alternative vascular access is equally possible, such as access through the subclavian artery or the axillary artery. After passing through the femoral artery, the catheter 12 may be pushed into the aorta such that the pump section 10 reaches through the aortic valve into the patient’s heart H. The positioning of the pump section 10 in Fig. 1 serves purely as an example, whereas different placements are possible, such as positioning the pump section 10 inside the right ventricle of the patient’s heart H.

[0053] The catheter 12 houses a flexible shaft 22 driven by the motor 102. The flexible shaft 22 drives the pump element 16 of the pump section 10. At its distal end, the pump section 10 comprises a flexible atraumatic tip 24 having the form of a pigtail or a J-form, which facilitates placement of the intravascular blood pump 100 by aiding navigation inside the patient’s vascular system. Furthermore, the softness of the flexible atraumatic tip 24 allows the pump section 10 to support itself atraumatically against the wall of the left ventricle LV.

[0054] As shown in Fig. 2, the pump housing 14 has a blood flow inlet 26 and a blood flow outlet 28. The pump element 16 is at least partially disposed in the pump housing 14, wherein the pump element 16 is configured to generate a blood flow between the blood flow inlet 26 and the blood flow outlet 28. The outflow tube 18 surrounds the blood flow outlet 28 of the pump housing 14 and has an outlet 60 for the blood flow. The outflow tube 18 is configured to channel the blood flow generated by the pump element 16.

[0055] The pump housing 14 is composed of a series of struts 30. The pump element 16 is provided in form of an impeller with at least one blade 32. The rotation of the impeller 16 around a central axis causes blood to flow from the blood flow inlet 26 at a distal end of the pump housing 14 to the blood flow outlet 28 located proximally of the blood flow inlet 26. The pump housing 14 includes an inner coating layer 34 and an outer coating layer 36 around the struts 30, the coating extends from the blood flow inlet 26 towards the blood flow outlet 28 by a fixed distance 38. The coating layers 34, 36 are made from an appropriate coating material, such as a polyurethane. The outflow tube 18 is connected to the outer coating layer 36 and covers and surrounds the blood flow outlet 28. The outflow tube 18 is collapsible. The outflow tube 18 is composed of a suitable biocompatible material, such as a suitable polymer, such as polyurethane, polyamide, nylon, or silicone. Preferably, the outflow tube 18 is made from polyurethane (PU) or polytetrafluoroethylene (PTFE). Of course, the outflow tube 18 may also be made of another suitable material, like polyethylene terephthalate (PET) or a polyamide. As shown in Fig. 1 , the outflow tube 18 may comprise at least one outlet opening forming the outlet 60. Here, the outlet openings are disposed in the aorta. The blood flow generated by the pump element 16 and exiting the blood flow outlet 28 flows along the inside of the outflow tube 18 and is delivered to the aorta via the outlet openings of the outlet 60.

[0056] The impeller 16 is offset from the blood flow inlet 26 by a predetermined distance 42. The impeller 16 is typically positioned such that a leading edge 44 of the impeller 16 is surrounded by the coating layers 34, 36. A trailing edge 46 of the impeller 16 may also be surrounded by the coating, or may extend beyond the trailing end of the coating. However, if the impeller 16 extends beyond the coating, at least a portion 48 of the entire length 50 of the impeller 16 is surrounded by the coating layers 34, 36.

[0057] As depicted in Fig. 2, the pump section 10 further comprises a mesh 52. The mesh 52 defines smaller openings than the openings defined by the struts 30 forming the pump housing 14. The mesh 52 is directly coupled to the struts 30 forming the pump housing 14 or to the outer coating layer 36. In some embodiments, the mesh 52 may be directly coupled to one or more struts 54 that are upstream (with respect to the direction of the flow of blood generated by the pump element 16) from the struts 30 forming the pump housing 14. In some embodiments, the mesh 52 may not be directly coupled to any struts 30, 54. The mesh 52 is positioned upstream from the impeller 16. In some embodiments, the mesh 52 may be positioned within an interior volume of space defined by the struts 30, 54. In some embodiments, the mesh 52 may be positioned external to the struts 30, 54. The struts 30, 54 are formed of an appropriate material, such as nitinol. The mesh is formed by an appropriate material, such as polyurethane.

[0058] In this embodiment, both the impeller 16, the pump housing 14 and the outflow tube 18 are compressible and expandable. For placing the blood pump 100 in the patient, the pump section 10 is advanced through the patient’s vascular system while the rotor 16, the pump housing 14 and the outflow tube 18 are in their compressed state. Once the pump section 10 is at its target location, the pump housing 14 and the rotor 16 are expanded. The blood flow generated by the pump element 16 then expands the outflow tube 18.

[0059] The stabilizing device 20 will now be explained with reference to Figs. 3 to 10. The stabilizing device 20 is located downstream of the blood flow outlet 28 of the pump housing 14. The stabilizing device 20 is configured to stabilize the pump section by influencing at least one flow parameter of the blood flow generated by the pump element 16.

[0060] In particular, downstream of the blood flow outlet 28 is to be understood with respect to the flow direction of the blood flow generated by the pump element 16. The at least one flow parameter may be any parameter associated with the blood flow such as a pressure, a volume flow or a direction of the blood flow. By influencing the at least one flow parameter downstream of the blood flow outlet 28, the stabilizing device 20 serves to reduce fluttering of the outflow tube 18 and to improve the positioning stability of the pump section 10.

[0061] Here, the at least one flow parameter comprises a differential pressure between an interior of the outflow tube 18 and an exterior of the outflow tube 18. The stabilizing device 20 is configured so that the differential pressure is at least a minimum differential pressure. The minimum differential pressure is preferably 5 mmHg. In the embodiments described in the following, the stabilizing device 20 comprises a throttle 62 for the blood flow generated by the pump element 16.

[0062] The differential pressure is calculated by subtracting the external pressure of the outflow tube 18 from the internal pressure of the outflow tube 18. That is, the internal pressure of the outflow tube 18 is at least 5 mmHg higher than the external pressure acting on the outflow tube 18 during the systole. In this respect, the stabilizing device 20 comprises the throttle 62 to cause the minimum differential pressure.

[0063] The throttle 62 may be formed by the outlet 60 of the outflow tube 18, see Figs. 3 to 5 and 7 to 11 , and / or by a throttle ring 64 attached to the outflow tube 18 forming the throttle 62 within the outflow tube 18, see Fig. 6. By influencing the differential pressure between the interior of the outflow tube 18 and the exterior of the outflow tube 18 to be at least the minimum differential pressure, the fluttering effect at the outlet 60 of the outflow tube 18 is reliably reduced over the whole cardiac cycle.

[0064] As can be seen in Fig. 6, the throttle ring 64 is disposed around an outer surface 66 of the outflow tube 18. The throttle ring 64 has a diameter DTthat is smaller than a diameter Doof the outflow tube 18 at the position where the throttle ring 64 is positioned. Thus, the throttle ring 64 locally constricts the outflow tube 18 forming the throttle 62 for the blood flow generated by the pump element 16 flowing through the outflow tube 18.

[0065] The outflow tube 18 has a distal end portion 68 connected to the pump housing 14, see Fig. 2, and a proximal end portion 70. The outflow tube 18 has an elongated configuration extending from the distal end portion 68 to the proximal end portion 70 along a longitudinal extension direction D1 of the outflow tube 18. As can be seen in Fig. 2, the outflow tube 18 has a connection angle C with respect to the pump housing at the distal end portion 68 of between 0.5 and 4 degrees, preferably between 1 and 2 degrees and further preferably of about 1 .5 degrees.

[0066] Here, the at least one flow parameter also comprises a resulting blood flow direction D2 at the outlet 60 of the outflow tube 18, see Fig. 5, for example. The stabilizing device 20 may be configured so that an axial portion D2a of the resulting blood flow direction D2 is directed away from the distal end portion 68 along the longitudinal extension direction D1 of the outflow tube 18, preferably the longitudinal extension direction D1 of the proximal end portion 70 of the outflow tube 18. Further preferably, the resulting blood flow direction D2 is substantially parallel to the longitudinal extension direction D1 of the outflow tube 18, preferably the longitudinal extension direction D1 of the proximal end portion 70 of the outflow tube 18.

[0067] As can be seen in Figs. 3 to 5 and 7 to 10, the stabilizing device 20 comprises the outlet 60 of the outflow tube 18. The outlet 60 of the outflow tube 18 is configured so that the differential pressure is at least the minimum differential pressure and so that the axial portion D2a of the resulting blood flow direction D2 is directed away from the distal end portion 68 of the outflow tube 18 along the longitudinal extension direction D1 of the outflow tube 18 and, in particular, the resulting blood flow direction D2 is substantially parallel to the longitudinal extension direction D1 of the outflow tube 18.

[0068] That is, the blood flow vector at the outlet 60 has the axial portion D2a parallel to the longitudinal extension direction D1 of the outflow tube 18 and a radial portion D2r perpendicular to the longitudinal extension direction D1 of the outflow tube 18. The vectorial addition of the two perpendicular portions D2a and D2r results in the resulting blood flow direction D2. The resulting blood flow direction D2 being substantially parallel to the longitudinal extension direction D1 means that the axial portion D2a of the blood flow vector is larger than the radial portion D2r of the blood flow vector.

[0069] As the axial portion D2a of the resulting blood flow direction D2 is directed away from the distal end portion 68 along the longitudinal extension direction D1 of the outflow tube 18, a thrust on the pump section 10 is generated in the opposite direction of the blood flow at the outlet 60. This thrust may also be referred to as an “axial thrust” on the pump section 10. By generating this axial thrust, fluttering of the outflow tube 18 is reduced and the positioning stability of the pump section 10 is improved.

[0070] As can be seen in Figs. 3 to 5 and 7 to 10, the outlet 60 of the outflow tube 18 is formed in or by the proximal end portion 70 of the outflow tube 18. Thus, the thrust generated by the outlet 60 takes effect over the entire longitudinal extension of the outflow tube 18 further assisting in reduced fluttering and improved positional stability. Additionally, the outlet 60 is suitably positioned to discharge the blood flow channeled by the outflow tube 18 into the aorta after the aortic valve. The catheter 12 has a circumferential surface 72. The proximal end portion 70 of the outflow tube 18 may comprise a tapered portion 74 tapered towards the catheter 12 and an attachment portion 76 attached to the circumferential surface 72 of the catheter 12. The tapered portion 74 and the attachment portion 76 can be seen in Fig. 4, for example.

[0071] In the embodiment of Figs. 3 to 5, the tapered portion 74 comprises three outlet openings 78. However, it will be readily understood that the number of outlet openings 78 is not limited to three. Specifically, the outlet openings 78 are holes in the outer surface 66 of the outflow tube 18. Here, the outlet 60 is formed by the three outlet openings 78 which are evenly distributed around the circumference of the tapered portion 74. In the embodiment of Figs. 3 to 5, the shape of the outlet openings 78 is substantially a rhombus. However, the shape of the outlet openings 78 may be any other suitable shape. The attachment portion 76 is attached to the circumferential surface 72 of the catheter 12 (not shown in Figs. 3 to 5) by bonding, for example by an adhesive or by thermal bonding. The tapered portion 74 may have a tapering angle A towards the catheter 12 of at least 40 degrees, preferably of at least 70 degrees, further preferably of at least 85 degrees. As can be seen in Fig.4, for example, the outlet opening 78 extend into the attachment portion 76.

[0072] Forming the outlet openings 78 in the tapered portion 74 facilitates directing the blood flow substantially in parallel to the longitudinal extension direction D1 of the outflow tube 18 rather than in a radial direction of the outflow tube 18, for example. The steeper the tapered portion 74 tapers towards the catheter 12, the larger the axial portion D2a of the blood flow vector becomes. Thus, the axial thrust on the pump section 10 generated by the outlet 60 is further increased and the positional stability of the pump section 10 is further improved.

[0073] The outflow tube 18 comprises an intermediate portion 80 connecting the distal end portion 68 and the proximal end portion 70 and the three outlet openings 78 are formed only in the proximal end portion 70. That is, the outlet openings do not extend over the tapered portion 74 into the intermediate portion 80 in a direction towards the distal end portion 68 of the outflow tube 18. This helps reduce the radial portion D2r of the resulting blood flow direction D2 at the outlet openings 78.

[0074] As can be seen in Figs. 3 and 4, for example, one of the three outlet openings 78 extends into a mounting-slit 82 in the attachment portion 76. The mounting-slit 82 in the attachment portion 76 is used during assembly of the pump section 10 to fold the outflow tube 18 over the already assembled pump housing 14. As can be seen in Fig. 5, it is sufficient that one of the three outlet openings 78 extends into one single mounting-slit 82 in the attachment portion 76. It is also conceivable, however, that each outlet opening 78 extends into a mounting-slit 82 in the attachment portion 76. In another embodiment, as shown in Fig. 11 , the tapered portion 74 comprises two outlet openings 78 forming the outlet 60. Here, each of the two outlet openings 74 extends into a mounting-slit 82 in the attachment portion 76. As can be seen in Fig. 11 , the outlet openings 78 in this embodiment are substantially drop-shaped.

[0075] In another embodiment, as shown in Figs. 7 and 8, the catheter 12 comprises three attachment struts 84 evenly distributed around the circumferential surface 72 of the catheter 12. The proximal end portion 70 of the outflow tube 18 comprises the attachment portion 76 which is attached to the three attachment struts 84. Here, the attachment portion 76 is a three-part attachment portion 76, wherein each part of the attachment portion 76 is attached to one of the three attachment struts 84 of the catheter 12. In this embodiment, the outlet 60 of the outflow tube 18 is formed by three outlet gaps 86 formed between the proximal end portion 70 of the outflow tube 18 and the catheter 12.

[0076] As can be seen in Fig. 7, the proximal end portion 70 of the present embodiment also comprises the tapered portion 74 without outlet openings 78. However, the tapered portion 74 may also comprise outlet openings 78 as described with reference to Figs. 3 to 5 in addition to the outlet gaps 86.

[0077] Also, the proximal end portion 70 does not need to have the tapered portion 74 and can directly be attached to the attachment struts 84. In this case, the height of the attachment struts 84 and the diameter of the proximal end portion 70 need to be matched accordingly so that no taper is necessary to attach the attachment portion 76 of the proximal end portion 70 to the attachment struts 84.

[0078] By providing the at least one outlet gap between the proximal end portion 70 of the outflow tube 18 and the catheter 12, the blood flow is directed in parallel to the longitudinal extension direction D1 of the outflow tube 18 and the blood flow vector has substantially no radial portion D2r, as can be seen in Fig. 7. Thus, the axial thrust created by the blood flow improves the positional stability of the pump section 10 and fluttering of the outflow tube 18 is reduced.

[0079] In the present embodiment, the attachment struts 84 are formed integrally with the catheter 12 on the circumferential surface 72 of the catheter 12. Alternatively, the catheter 12 may comprise an attachment ring (not shown) having the at least one attachment strut, wherein the attachment ring is connected to the circumferential surface 72 of the catheter 12. The connection between the attachment ring and the catheter 12 may be formed by bonding, for example by an adhesive or by thermal bonding.

[0080] In another embodiment, as can be seen in Fig. 9, the proximal end portion 70 of the outflow tube 18 comprises an attachment strip 88 attached to the circumferential surface 72 of the catheter 12. Specifically, the proximal end portion 70 comprises four attachment strips 88 of which two can be seen in Fig. 9. The proximal end portion 70 of the outflow tube 18 further comprises an outlet pocket 90 with an outlet opening 92. Specifically, four outlet pockets 90 are formed in that the four attachment strips are attached to the circumferential surface 72 of the catheter 12. The outlet 60 of the outflow tube 18 is formed by the four outlet pockets 90 in this embodiment. As can be seen schematically in Fig. 9, the outlet pockets 90 form a four-leaf cloverleaf shape.

[0081] Specifically, the outflow tube 18 extends into the four attachment strips 88 at its proximal end portion 70. In this case, the proximal end portion 70 does not taper towards the catheter 12. By attaching the attachment strips 88 to the catheter 12, longitudinal constrictions 94 in the longitudinal extension direction D1 of the outflow tube 18 are formed, resulting in the four outlet pockets 90. Towards the left in Fig. 9, the longitudinal constrictions 94 fade out into the full diameter of the outflow tube 18, which is schematically indicated by dashed lines in Fig. 9.

[0082] In another embodiment, as can be seen in Fig. 10, the outflow tube 18 comprises a guide tube 95 in fluid connection with the outflow tube 18. Specifically, the outflow tube 18 has three guide tubes 95 evenly distributed in a circumferential direction around the intermediate portion 80. Two of the guide tubes 95 are schematically shown in Fig. 10. The guide tubes 95 extend substantially in parallel to the longitudinal extension direction D1 of the outflow tube 18. In this embodiment, the outlet 60 of the outflow tube 18 is formed by the guide tubes 95. The guide tubes 95 end in an outflow opening 96 oriented so that the blood flow exits the guide tube 95 substantially in parallel to the longitudinal extension direction D1 of the outflow tube 18. As can be seen in Fig. 10, the guide tubes 95 are disposed radially outside of the outer surface 66 of the outflow tube 18.

[0083] In the present embodiment, the intermediate portion 80 comprises multiple openings 97 evenly distributed in a circumferential direction around the intermediate portion 80. One guide tube 95 is connected to each opening 97 in the intermediate portion 80. The fluid connection between the outflow tube 18 and the guide tube 95 is formed by bonding, for example by an adhesive or by thermal bonding, of one end of the guide tube 95 to the outer surface 66 of the outflow tube 18 around the opening 97 in the intermediate portion 80. Alternatively, the guide tubes 95 may be formed integrally with the outflow tube 18.

[0084] An outer surface 98 of the guide tubes 95 is partially bonded to the outer surface 66 of the outflow tube 18, for example by an adhesive or by thermal bonding. That is, the outer surface 98 of each guide tube 95 is bonded to the outer surface 66 of the outflow tube 18 where the outer surface 98 and the outer surface 66 are in contact with each other. In the present embodiment, as can be seen in Fig. 10, the pump section 10 further comprises a positioning ring 99 surrounding the at least one guide tube 95 and the outflow tube 18. The positioning ring 99 serves to hold the guide tubes 95 in place and to ensure that the outflow opening 96 of the guide tube 95 is oriented so that the blood flow exits the guide tube 95 substantially in parallel to the longitudinal extension direction D1 of the outflow tube 18. As the guide tubes 95 are also bonded to the outflow tube 18 along their contact surface, the positioning ring 99 can be omitted.

[0085] The positioning ring 99 of Fig. 10 and the throttle ring 64 are made from silicone, for example, and attached to the outflow tube 18 and the guide tubes 95, respectively, via a suitable adhesive.

[0086] Alternatively, the guide tubes 95 shown in Fig. 10 may also be formed extending from the tapered portion 74 of the proximal end portion 70.

[0087] In the embodiments of Figs. 3 to 5 and 7 to 10, the outlet 60 has a total outlet area of between 20 mm2and 70 mm2, specifically between 30 mm2and 50 mm2, and more specifically between 33 mm2and 35 mm2. In the embodiment of Fig. 6, the outlet 60 may also have a total outlet area of more than 70 mm2as the throttle ring 64 provides the throttle effect for the blood flow thus reducing fluttering of the outflow tube. It is, however, more preferable if the outlet 60 has a total outlet area of less than 70 mm2also in the embodiment of Fig. 6.

[0088] As will be apparent to the skilled person, the features described with respect to the different embodiments above can be combined as long as they do not contradict each other.

[0089] The total outlet area is calculated by adding the area of all openings through which the blood flow generated by the pump element 16 exits the outflow tube 18. That is, the total outlet area may comprise the total area of all outlet openings 78 in the outflow tube 18 and / or the total area of all outlet gaps 86 and / or the total area of all outflow openings 96 of the guide tubes 95. By providing a total outlet area of equal to or less than 70 mm2, the outlet 60 forms a throttle 62 for the blood flow generated by the pump element 16 exiting the outflow tube 18. Thus, the desired minimum differential pressure of at least 10 mmHg between the interior of the outflow tube 18 and the exterior of the outflow tube 18 is ensured. Additionally, the outlet 60 then functions as a nozzle for the blood flow exiting the outflow tube 18 resulting in the desired axial thrust. Thus, the fluttering of the outflow tube 18 is reduced and the positioning stability of the pump section 10 is improved. EXEMPLARY IMPLEMENTATIONS

[0090] As already described, the technology described herein may be implemented in various ways. In that regard, the foregoing disclosure is intended to include, but not be limited to, the systems, methods, and combinations and sub-combinations thereof that are set forth in the following exemplary implementations. Preferred embodiments are described in the following paragraphs:

[0091] A1 Pump section for a blood pump, the pump section comprising: a pump housing having a blood flow inlet and a blood flow outlet; a pump element at least partially disposed in the pump housing, wherein the pump element is configured to generate a blood flow between the blood flow inlet and the blood flow outlet; an outflow tube surrounding the blood flow outlet of the pump housing, wherein the outflow tube is configured to channel the blood flow generated by the pump element, wherein the outflow tube has an outlet for the blood flow; and a stabilizing device located downstream of the blood flow outlet of the pump housing, wherein the stabilizing device is configured to stabilize the pump section by influencing at least one flow parameter of the blood flow generated by the pump element.

[0092] A2 Pump section according to paragraph A1 , wherein the flow parameter comprises a pressure, a volume flow, or a direction of the blood flow generated by the pump element.

[0093] A3 Pump section according to paragraph A1 or A2, wherein the at least one flow parameter comprises a differential pressure between an interior of the outflow tube and an exterior of the outflow tube, and the stabilizing device is configured so that the differential pressure is at least a minimum differential pressure.

[0094] A4 Pump section according to paragraph A3, wherein the differential pressure between the interior and the exterior of the outflow tube is calculated by subtracting the external pressure of the outflow tube from the internal pressure of the outflow tube.

[0095] A5 Pump section according to paragraph A3 or A4, wherein the differential pressure is the minimum differential pressure over the whole cardiac cycle including diastole and systole.

[0096] A6 Pump section according to any one of paragraphs A3 to A5, wherein the minimum differential pressure is 5 mmHg, preferably 10 mmHg.

[0097] A7 Pump section according to any one of the preceding paragraphs, wherein the stabilizing device comprises a throttle for the blood flow generated by the pump element.

[0098] A8 Pump section according to paragraph A7, wherein the throttle comprises a throttle ring, preferably made from silicone.

[0099] A9 Pump section according to paragraph A8, wherein the throttle ring is disposed around an outer surface of the outflow tube.

[0100] A10 Pump section according to paragraph A8 or A9, wherein the throttle ring has a diameter that is smaller than a diameter of the outflow tube at the position where the throttle ring is positioned.

[0101] A11 Pump section according to any one of paragraphs A8 to A10, wherein the throttle ring locally constricts the outflow tube forming a throttle for the blood flow generated by the pump element flowing through the outflow tube.

[0102] A12 Pump section according to any one of the preceding paragraphs, wherein the outflow tube has a distal end portion connected to the pump housing and a proximal end portion, wherein the outflow tube has an elongated configuration extending from the distal end portion to the proximal end portion along a longitudinal extension direction of the outflow tube, the at least one flow parameter comprises a resulting blood flow direction at the outlet of the outflow tube, and the stabilizing device is configured so that an axial portion of the resulting blood flow direction is directed away from the distal end portion along the longitudinal extension direction of the outflow tube, preferably the resulting blood flow direction is substantially parallel to the longitudinal extension direction of the outflow tube.

[0103] A13 Pump section according to paragraph A12, wherein the axial end portion of the resulting blood flow direction is directed away from the distal end portion along the longitudinal extension direction of the proximal end portion of the outflow tube, preferably the resulting blood flow direction is substantially parallel to the longitudinal extension direction of the proximal end portion of the outflow tube.

[0104] A14 Pump section according to any one of the preceding paragraphs, wherein the stabilizing device comprises the outlet of the outflow tube.

[0105] A15 Pump section according to any one of the preceding paragraphs, wherein the outlet of the outflow tube forms a throttle for the blood flow generated by the pump element flowing through the outflow tube.

[0106] A16 Pump section according to any one of the preceding paragraphs, wherein the outlet of the outflow tube is formed in or by the proximal end portion of the outflow tube.

[0107] A17 Pump section according to any one of the preceding paragraphs, wherein the pump section further comprises a catheter connected to the pump housing, wherein the catheter has a circumferential surface.

[0108] A18 Pump section according to any one of the preceding paragraphs, wherein the proximal end portion of the outflow tube comprises a tapered portion tapered towards the catheter and an attachment portion attached to the circumferential surface of the catheter, the tapered portion comprises at least one outlet opening, preferably at least one outlet hole, and the outlet of the outflow tube is formed by the at least one outlet opening.

[0109] A19 Pump section according to paragraph A18, wherein the tapered portion comprises multiple outlet openings, preferably three outlet openings, evenly distributed in a circumferential direction around the tapered portion.

[0110] A20 Pump section according to paragraph A18 or A19, wherein the shape of the at least one outlet opening is a circle, an elongated circle, an arch, a semicircle, an elongated semi-circle, an oval, a rhombus, a triangle or a drop shape.

[0111] A21 Pump section according to any one of paragraphs A18 to A20, wherein the at least one outlet opening has rounded corners.

[0112] A22 Pump section according to any one of paragraphs A18 to A21 , wherein the tapered portion has a tapering angle towards the catheter of at least 40 degrees, preferably of at least 70 degrees, further preferably of at least 85 degrees.

[0113] A23 Pump section according to any one of paragraphs A16 to A22, wherein the pump section further comprises a catheter connected to the pump housing, wherein the catheter has a circumferential surface, wherein the catheter comprises at least one attachment strut.

[0114] A24 Pump section according to paragraph A23, wherein the catheter comprises multiple attachment struts, preferably three attachment struts, evenly distributed around the circumferential surface of the catheter.

[0115] A25 Pump section according to paragraph A23 or A24, wherein the proximal end portion of the outflow tube comprises an attachment portion attached to the at least one attachment strut, and the outlet of the outflow tube is formed by at least one outlet gap formed between the proximal end portion of the outflow tube and the catheter.

[0116] A26 Pump section according to paragraph A25, wherein the outlet is formed by multiple outlet gaps, preferably three outlet gaps, formed between the proximal end portion of the outflow tube and the catheter.

[0117] A27 Pump section according to any one of paragraphs A23 to A26, wherein the at least one attachment strut is formed integrally with the catheter on the circumferential surface of the catheter.

[0118] A28 Pump section according to any one of paragraphs A23 to A26, wherein the catheter comprises an attachment ring having the at least one attachment strut, wherein the attachment ring is connected to the circumferential surface of the catheter.

[0119] A29 Pump section according to paragraph A16, wherein the pump section further comprises a catheter connected to the pump housing, wherein the catheter has a circumferential surface, the proximal end portion of the outflow tube comprises at least one attachment strip attached to the circumferential surface of the catheter.

[0120] A30 Pump section according to paragraph A29, wherein the proximal end portion comprises multiple attachment strips, preferably four attachment strips, attached to the circumferential surface of the catheter.

[0121] A31 Pump section according to paragraph A29 or A30, wherein the proximal end portion of the outflow tube further comprises at least one outlet pocket with an outlet opening, preferably multiple outlet pockets.

[0122] A32 Pump section according to paragraph A31 , wherein the at least one outlet pocket is formed in that the at least one attachment strip is attached to the circumferential surface of the catheter, and the outlet of the outflow tube is formed by the at least one outlet pocket, wherein preferably multiple outlet pockets form a cloverleaf shape.

[0123] A33 Pump section according to any one of paragraphs A18 to A32, wherein the attachment portion is attached to the catheter by bonding, in particular by an adhesive or by thermal bonding.

[0124] A34 Pump section according to any one of paragraphs A18 to A33, wherein the at least one outlet opening extends into a mounting-slit in the attachment portion.

[0125] A35 Pump section according to any one of the preceding paragraphs, wherein the outflow tube comprises at least one guide tube in fluid connection with the outflow tube.

[0126] A36 Pump section according to paragraph A35, wherein the outflow tube comprises multiple guide tubes, preferably three guide tubes, in fluid connection with the outflow tube.

[0127] A37 Pump section according to paragraph A35 or A36, wherein the at least one guide tube extends substantially in parallel to the longitudinal extension direction of the outflow tube, and the outlet of the outflow tube is formed by the at least one guide tube.

[0128] A38 Pump section according to any one of paragraphs A35 to A37, wherein the outflow tube comprises an intermediate portion connecting the distal end portion and the proximal end portion, the intermediate portion comprises multiple openings, preferably three openings, evenly distributed in a circumferential direction around the intermediate portion, and one guide tube is connected to each opening in the intermediate portion.

[0129] A39 Pump section according to any one of paragraphs A35 to A38, wherein an outer surface of the at least one guide tube is at least partially bonded to an outer surface of the outflow tube.

[0130] A40 Pump section according to any one of paragraphs A35 to A39, wherein the pump section further comprises a positioning ring, preferably made from silicone, surrounding the at least one guide tube and the outflow tube.

[0131] A41 Pump section according to paragraph A40, wherein the positioning ring is at least partially bonded, preferably by an adhesive or by thermal bonding, to an outer surface of the guide tube.

[0132] A42 Pump section according to paragraph A41 , wherein the positioning ring is at least partially bonded, preferably by an adhesive or by thermal bonding, to an outer surface of the outflow tube.

[0133] A43 Pump section according to any one of the preceding paragraphs, wherein the outlet has a total outlet area of between 20 mm2and 70 mm2, preferably between 30 mm2and 50 mm2, further preferably between 33 mm2and 35 mm2.

[0134] A44 Pump section according to any one of the preceding paragraphs, wherein the pump housing has a strut structure made of nitinol.

[0135] A45 Pump section according to any one of the preceding paragraphs, wherein the pump housing has a mesh associated with the blood flow inlet, wherein the mesh is made from polyurethane.

[0136] A46 Pump section according to paragraphs A44 and A45, wherein the mesh defines smaller openings than the openings defined by the strut structure.

[0137] A47 Pump section according to any one of the preceding paragraphs, wherein the outflow tube is made from polyurethane.

[0138] A48 Pump section according to any one of the preceding paragraphs, wherein the outflow tube has a connection angle with respect to the pump housing at the distal end portion of between 0.5 and 4 degrees.

[0139] A49 Pump section according to paragraph A48, wherein the connection angle is between 1 and 2 degrees.

[0140] A50 Pump section according to paragraph A49, wherein the connection angle is about 1 .5 degrees.

[0141] B1 Pump section for a blood pump, the pump section comprising: a pump housing having a blood flow inlet and a blood flow outlet; a pump element at least partially disposed in the pump housing, wherein the pump element is configured to generate a blood flow between the blood flow inlet and the blood flow outlet; and an outflow tube surrounding the blood flow outlet of the pump housing, wherein the outflow tube is configured to channel the blood flow generated by the pump element, wherein the outflow tube has an outlet for the blood flow; wherein the outflow tube has a distal end portion connected to the pump housing and the outflow tube has a connection angle with respect to the pump housing at the distal end portion of between 0.5 and 4 degrees, preferably between 1 and 2 degrees, further preferably of about 1 .5 degrees.

[0142] B2 Blood pump according to paragraph B1 , wherein the blood pump further comprises a stabilizing device located downstream of the blood flow outlet of the pump housing, wherein the stabilizing device is configured to stabilize the pump section by influencing at least one flow parameter of the blood flow generated by the pump element.

[0143] C1 Blood pump comprising a pump section according to any one of the preceding paragraphs.

[0144] C2 Blood pump according to paragraph C1 , wherein the blood pump is an intravascular blood pump.

[0145] C3 Blood pump according to paragraph C1 or C2, wherein the blood pump further comprises a motor.

[0146] C4 Blood pump according to paragraph C3, wherein the motor drives the pump element of the pump section.

[0147] C5 Blood pump according to paragraph C4, wherein the catheter of the pump section houses a flexible shaft driven by the motor.

[0148] C6 Blood pump according to paragraph C5, wherein the flexible shaft drives the pump element.

[0149] As utilized herein, the terms “approximately”, “about”, “substantially” and similar terms are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. As utilized herein, "proximal" and "distal" are seen relative to the medical staff or physician. Thus, proximal designates something which is relatively close to the physician whereas distal designates something which is relatively far away from the physician when the blood pump is introduced into the patient’s body. It should be understood by those of skill in the art who review this disclosure that these terms are intended to allow a description of certain features described without restricting the scope of these features to the precise numerical ranges provided. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter are described and are considered to be within the scope of the disclosure. The terms „at least partially” or “partially” as used herein mean both partial and entirely or complete respectively. Terms like “first”, “second” or “third” do not denote a specific order, but are only intended to semantically differentiate between the elements.

[0150] LIST OF REFERENCE SIGNS

[0151] 10 pump section

[0152] 12 catheter

[0153] 14 pump housing

[0154] 16 pump element / impeller

[0155] 18 outflow tube

[0156] 20 stabilizing device

[0157] 22 flexible shaft

[0158] 24 flexible atraumatic tip

[0159] 26 blood flow inlet

[0160] 28 blood flow outlet

[0161] 30 struts of the pump housing

[0162] 32 blade of the pump element

[0163] 34 inner coating layer

[0164] 36 outer coating layer

[0165] 38 fixed distance

[0166] 42 predetermined distance

[0167] 44 leading edge

[0168] 46 trailing edge

[0169] 48 portion of the pump element / impeller

[0170] 50 length of the pump element / impeller

[0171] 52 mesh

[0172] 54 struts

[0173] 60 outlet

[0174] 62 throttle

[0175] 64 throttle ring

[0176] 66 outer surface of the outflow tube

[0177] 68 distal end portion of the outflow tube

[0178] 70 proximal end portion of the outflow tube

[0179] 72 circumferential surface of the catheter

[0180] 74 tapered portion of the outflow tube 76 attachment portion of the outflow tube

[0181] 78 outlet opening in the tapered portion

[0182] 80 intermediate portion of the outflow tube

[0183] 82 mounting slit

[0184] 84 attachment strut

[0185] 86 outlet gap

[0186] 88 attachment strip

[0187] 90 outlet pocket

[0188] 92 outlet opening

[0189] 94 longitudinal constriction

[0190] 95 guide tube

[0191] 96 outflow opening

[0192] 97 opening in the intermediate portion

[0193] 98 outer surface of the guide tube

[0194] 99 positioning ring

[0195] 100 blood pump

[0196] 102 motor

[0197] A tapering angle

[0198] C connection angle

[0199] DTdiameter of the throttle ring

[0200] Dodiameter of the outflow tube at the location of the throttle ring

[0201] H patient’s heart

[0202] LV left ventricle

Claims

CLAIMS1 . Pump section (10) for a blood pump (100), the pump section (10) comprising: a pump housing (14) having a blood flow inlet (26) and a blood flow outlet (28); a pump element (16) at least partially disposed in the pump housing (14), wherein the pump element (16) is configured to generate a blood flow between the blood flow inlet (26) and the blood flow outlet (28); an outflow tube (18) surrounding the blood flow outlet (28) of the pump housing (14), wherein the outflow tube (18) is configured to channel the blood flow generated by the pump element (16), wherein the outflow tube (18) has an outlet (60) for the blood flow; and a stabilizing device (20) located downstream of the blood flow outlet (28) of the pump housing (14), wherein the stabilizing device (20) is configured to stabilize the pump section (10) by influencing at least one flow parameter of the blood flow generated by the pump element (16).

2. Pump section (10) according to claim 1 , wherein the at least one flow parameter comprises a differential pressure between an interior of the outflow tube (18) and an exterior of the outflow tube (18), and the stabilizing device (20) is configured so that the differential pressure is at least a minimum differential pressure, wherein the minimum differential pressure is preferably 5 mmHg, wherein the stabilizing device (20) preferably comprises a throttle (62) for the blood flow generated by the pump element (16).

3. Pump section (10) according to claim 1 or 2, wherein the outflow tube (18) has a distal end portion (68) connected to the pump housing (14) and a proximal end portion (70), wherein the outflow tube (18) has an elongated configuration extending from the distal end portion (68) to the proximal end portion (70) along a longitudinal extension direction (D1) of the outflow tube (18), the at least one flow parameter comprises a resulting blood flow direction (D2) at the outlet (60) of the outflow tube (18), and the stabilizing device (20) is configured so that an axial portion (D2a) of the resulting blood flow direction (D2) is directed away from the distal end portion (68) along the longitudinal extension direction (D1) of the outflow tube (18), preferably the longitudinal extension direction (D1) of the proximal end portion (70) of the outflow tube (18).

4. Pump section (10) according to any one of claims 1 to 3, wherein the stabilizing device (20) comprises the outlet (60) of the outflow tube (18).

5. Pump section (10) according to any of the preceding claims, wherein the outlet (60) of the outflow tube (18) is formed in or by the proximal end portion (70) of the outflow tube (18).

6. Pump section (10) according to claim 5, wherein the pump section (10) further comprises a catheter (12) connected to the pump housing (14), wherein the catheter (12) has a circumferential surface (72), the proximal end portion (70) of the outflow tube (18) comprises a tapered portion (74) tapered towards the catheter (12) and an attachment portion (76) attached to the circumferential surface (72) of the catheter (12), the tapered portion (74) comprises at least one outlet opening (78), preferably at least one outlet hole, and the outlet (60) of the outflow tube (18) is formed by the at least one outlet opening (78), preferably multiple outlet openings (78) evenly distributed in a circumferential direction around the tapered portion (74), wherein the shape of the at least one outlet opening (78) is preferably a circle, an elongated circle, an arch, a semi-circle, an elongated semi-circle, an oval, a rhombus, a triangle, or a drop shape wherein the at least one outlet opening (78) preferably has rounded corners.

7. Pump section (10) according to claim 6, wherein the tapered portion (74) has a tapering angle (A) towards the catheter (12) of at least 40 degrees, preferably of at least 70 degrees, further preferably of at least 85 degrees.

8. Pump section (10) according to claim 5, wherein the pump section (10) further comprises a catheter (12) connected to the pump housing (14), wherein the catheter (12) has a circumferential surface (72), wherein the catheter (12) comprises at least one attachment strut (84), preferably multiple attachment struts (84) evenly distributed around the circumferential surface (72) of the catheter (12), the proximal end portion (70) of the outflow tube (18) comprises an attachment portion (76) attached to the at least one attachment strut (84), and the outlet (60) of the outflow tube (18) is formed by at least one outlet gap (86), preferably multiple outlet gaps (86), formed between the proximal end portion (70) of the outflow tube (18) and the catheter (12).

9. Pump section (10) according to claim 8, wherein the at least one attachment strut (84) is formed integrally with the catheter (12) on the circumferential surface (72) of the catheter (12), orthe catheter (12) comprises an attachment ring having the at least one attachment strut (84), wherein the attachment ring is connected to the circumferential surface (72) of the catheter (12).

10. Pump section (10) according to claim 5, wherein the pump section (10) further comprises a catheter (12) connected to the pump housing (14), wherein the catheter (12) has a circumferential surface (72), the proximal end portion (70) of the outflow tube (18) comprises at least one attachment strip (88), preferably multiple attachment strips (88), attached to the circumferential surface (72) of the catheter (12), wherein the proximal end portion (70) of the outflow tube (18) further comprises at least one outlet pocket (90) with an outlet opening (78), preferably multiple outlet pockets (90), wherein the at least one outlet pocket (90) is formed in that the at least one attachment strip (88) is attached to the circumferential surface (72) of the catheter (12), and the outlet (60) of the outflow tube (18) is formed by the at least one outlet pocket (90), wherein preferably multiple outlet pockets (90) form a cloverleaf shape.11 . Pump section (10) according to any one of claims 1 to 4, wherein the outflow tube (18) comprises at least one guide tube (95), preferably multiple guide tubes (95), in fluid connection with the outflow tube (18), wherein the at least one guide tube (95) extends substantially in parallel to the longitudinal extension direction (D1) of the outflow tube (18), and the outlet (60) of the outflow tube (18) is formed by the at least one guide tube (95).

12. Pump section (10) according to claim 11 , wherein the outflow tube (18) comprises an intermediate portion (80) connecting the distal end portion (68) and the proximal end portion (70), the intermediate portion (80) comprises multiple openings (97) evenly distributed in a circumferential direction around the intermediate portion (80), and one guide tube (95) is connected to each opening (97) in the intermediate portion (80).

13. Pump section (10) according to any one of the preceding claims, wherein the outlet (60) has a total outlet area of between 20 mm2and 70 mm2, preferably between 30 mm2and 50 mm2, further preferably between 33 mm2and 35 mm2.

14. Pump section (10) for a blood pump (100), in particular according to any one of the preceding claims, the pump section (10) comprising: a pump housing (14) having a blood flow inlet (26) and a blood flow outlet (28);a pump element (16) at least partially disposed in the pump housing (14), wherein the pump element (16) is configured to generate a blood flow between the blood flow inlet (26) and the blood flow outlet (28); and an outflow tube (18) surrounding the blood flow outlet (28) of the pump housing (14), wherein the outflow tube (18) is configured to channel the blood flow generated by the pump element (16), wherein the outflow tube (18) has an outlet (60) for the blood flow; wherein the outflow tube (18) has a distal end portion (68) connected to the pump housing (14) and the outflow tube (18) has a connection angle (C) with respect to the pump housing (14) at the distal end portion (68) of between 0.5 and 4 degrees, preferably between 1 and 2 degrees, further preferably of about 1 .5 degrees.

15. Blood pump (100), in particular intravascular blood pump (100), comprising a pump section (10) according to any one of the preceding claims.

Images