DE102023103518A1 - Cardiac catheter pump - Google Patents

Abstract

The invention relates to a cardiac catheter pump comprising a preferably flexible cannula (1) which has an inlet region (2) at its distal end and a pump housing (3) with an impeller (4) and an outlet region (5) at its proximal end, in particular wherein blood can be conveyed from the inlet region (2) to the outlet region (4) by rotation of the impeller (4), and a drive (6) connected to the pump housing (3) with which the impeller (4) can be set in rotation in the pump housing (3), wherein the drive (6) comprises a series arrangement of several drive units (6a, 6b, 6c, 6d) which are flexibly connected to one another.

Description

The invention relates to a cardiac catheter pump comprising a cannula, preferably a flexible cannula, which has an inlet region at its distal end and a pump housing with an impeller and an outlet region at its proximal end, in particular wherein blood can be conveyed from the inlet region to the outlet region by rotation of the impeller, and a drive connected to the pump housing, with which the impeller can be set in rotation in the pump housing.

The location or direction information, such as “distal” (inlet) or “proximal” (outlet), are given from the perspective of a treating physician.

Such cardiac catheter pumps are generally known in the art, e.g. from the publication DE 103 36 902 B3 .

This type of pump is used to suck blood from the heart and pump it into the aorta, thereby supporting the heart. In order to position the cardiac catheter pump correctly, it must be sufficiently flexible to be able to pass through the aortic arch. This required flexibility therefore limits the maximum possible rigid length of the pump housing and drive, with the length of the drive also influencing its drive power. Rigid length is understood to be the length of the cardiac catheter pump over which the cardiac catheter pump cannot be bent.

Therefore, the parameters of drive power and rigid length limit each other.

Against this background, it is an object of the invention to provide an improved cardiac catheter pump that offers increased flexibility while at the same time providing high drive performance. Preferably, it is also an object to create a cardiac catheter pump that can be advanced to the heart via alternative access routes due to increased flexibility.

This object is achieved according to the invention in that the drive comprises a series arrangement of several drive units which are flexibly connected to one another.

The invention takes advantage of the fact that the drive torques of the individual drive units add up to a total torque, so that all drive units together drive the impeller.

In this way, a high drive power can be achieved without increasing the rigid length of the cardiac catheter pump, because the flexible connection of the drive units to one another makes it possible to bend the cardiac catheter pump in the area of the drive, so that the cardiac catheter pump can follow the natural curvature of vessels, such as the aortic arch, without damaging the vessels during implantation. The rigid length of the cardiac catheter pump is only limited by the length of the rigid/rigid area of a particular drive unit or the longest of all drive units. Preferably, all drive units have the same rigid length.

It can also be provided that at least some of the multiple drive units have different rigid lengths. For example, drive units with a shorter rigid length compared to other drive units in the said series arrangement can be arranged at positions where a greater curvature is required later in the use of the pump than in other areas of the series arrangement.

The flexible connection between the individual drive units of the drive is designed in such a way that the sequential arrangement of drive units can be bent/curved from an exact straight line. This means that not only can the flexible cannula take on a curve, but the sequential arrangement of the drive units can also take on a curved course. This means that the sequential arrangement can follow the curvature of the lumen of a body vessel, e.g. the aortic arch.

Preferably, the respective flexible connection between the drive units is designed such that areas of the series arrangement in front of and behind a respective flexible connection, in particular two adjacent drive units, are movable around a point or area within the area of their flexible connection.

In one possible embodiment, the invention can provide that the distal drive unit of the series arrangement of all drive units comprises the pump housing or is rigidly connected to the pump housing.

This can result in a rigid length of the cardiac catheter pump that is greater than the length of a single drive unit, in particular the length of the distal drive unit, namely increased by the rigid length of the pump housing. Nevertheless, this design can be used due to a simplified construction in the Coupling between drive unit and pump housing is preferred.

The invention can preferably also provide that the distal drive unit of the series arrangement of all drive units is flexibly connected to the pump housing.

In the invention, it can be provided that the drive comprises at least two, preferably at least three, more preferably at least four drive units arranged one behind the other and flexibly connected. Preferably, all drive units have identical power and/or identical torque and/or identical rigid length.

It can also be provided that the drive units of a cardiac catheter pump according to the invention are or can be connected to one another in a detachable manner. For this purpose, the flexible connection and the electrical connection between the drive units can be designed to be detachable. Depending on the required power, it is thus possible to combine more or fewer drive units to drive the cardiac catheter pump according to the invention.

It is also possible to provide sets of at least two cardiac catheter pumps of the type according to the invention, in which each cardiac catheter pump has a different number of drive units. This allows a user to select a suitable cardiac catheter pump from the set as required.

Preferably, it is provided that each drive unit comprises a housing with a stator arranged in the housing in a rotationally fixed manner and a rotor rotatably mounted in the housing, wherein the housings of all drive units are connected to one another in a rotationally fixed and flexibly manner and the rotors of all drive units are connected to one another in a rotationally fixed manner and, in particular at least outside the housings, flexibly.

It is preferably provided that the stator and rotor work together electromagnetically to drive the rotor. Each drive unit thus preferably forms an electric motor.

The invention can provide that each drive unit is supplied with the same at least one electrical control signal, e.g. from a control unit, so that all drive units work synchronously. The control signal can be used to control the power of the drive units, e.g. discretely (in the simplest case on or off) or continuously. For this purpose, at least one common control signal line can be routed from a control unit to each of the drive units in succession, preferably with the drive units all being electrically connected in parallel to the at least one control signal line. Preferably, the at least one control signal line coming from the control unit is connected to the proximal drive unit and is successively routed from drive unit to drive unit as far as the distal drive unit.

The individual drive units can also be operated synchronously by controlling the individual drive units with a rotating field of identical frequency, whereby the mechanical coupling of the rotor elements results in identical slip in all drive units.

Synchronization can also be achieved by a control system that feeds an independent control signal into the individual drive units. Each drive unit therefore preferably has its own control signal. It can preferably be provided that a possible mechanical slip is compensated by an individual phase offset between the individual control signals. In particular, an input variable for the control of the control signals can be, for example, the voltages of a counteracting electromotive force in sensorless motor operation or the measured speed.

A possible preferred embodiment of the invention can provide that the rotors of adjacent drive units each have their own rigid rotor shaft and the rotor shafts of adjacent drive units are flexibly connected, in particular by a section of a flexible shaft or by joints, in particular cardan joints, as a flexible connecting element. This respective rigid rotor shaft, but also the rotor shafts of the embodiments to be described below, can preferably be rotatably mounted in the housing of the drive unit, in particular at the location of the opposite end walls of the respective housing.

The fastening between the rigid rotor shaft and a section of a flexible shaft can preferably be designed to be positively locking and/or non-positively locking and/or materially locking, e.g. by gluing or welding.

Particularly in the case of form-fitting and/or force-fitting fastenings, designs can be provided in which the drive units can be detachably coupled to one another.

Another possible preferred embodiment of the invention can provide that the rotors of adjacent drive units all have a common rotor shaft, preferably a one-piece rotor shaft, wherein the common rotor shaft is designed to be rigid in a respective section within a drive unit and is designed to be flexible in a respective section between adjacent drive units.

Preferably, the common rotor shaft is formed by a tube, in particular at least one tube, which is designed to be flexible in a respective section between adjacent drive units by material processing, in particular as a flexible connecting element. The rotor shaft can also be formed by two or more such nested tubes, preferably which contact each other in the radial direction.

By means of such material processing, preferably at least one incision or incisions, particularly preferably spiral or helical incisions or at least one spiral or helical incision, is introduced into the pipe, which thus leads to flexibility of the pipe in the region of the incisions or of the at least one incision.

With a rotor shaft cut in this way, areas of the rotor shaft on both sides of the at least one cut can be positively connected to one another, in particular interlocked, e.g. by an undercut projection in the rotor shaft on one side of the cut, which lies in a corresponding, in particular negatively shaped recess on the other side of the cut. The connection of projection and recess can be designed, for example, as a dovetail connection. Preferably, several such connection areas are arranged equidistantly along a cut. This can achieve axial and/or rotational stabilization of the rotor shaft. At least two groups of several axially spaced cuts can also be arranged in the rotor shaft, the respective cuts extending at least partially in the circumferential direction around the rotor shaft axis, in particular having a slope in the axial direction, the ends of cuts in one group lying between the ends of cuts in another group due to the axial offset of the groups to one another. The incisions of each group may preferably widen from the two ends towards the centre of the respective incision.

This respective design with at least one incision has the advantage that the common rotor shaft running through all drive units avoids coupling points and the associated mechanical vulnerabilities between the drive units, in particular at the component interfaces.

Another possible preferred embodiment of the invention can provide that the rotors of adjacent drive units all have a common rotor shaft, in particular a one-piece rotor shaft, wherein the common rotor shaft is designed to be flexible throughout, in particular as a flexible connecting element, and is received in a respective rotor, preferably in a hollow rotor shaft of the rotor, in a form-fitting and/or material-fitting manner.

The form-fitting and/or material-fitting mounting of the flexible rotor shaft within the respective rotor results in the flexible rotor shaft being stiffened, i.e. it loses its flexibility at the location within the rotor.

This also avoids coupling points and/or component interfaces and the associated mechanical vulnerabilities between the drive units. Furthermore, commercially available flexible shafts can be used directly.

Preferably, it can also be provided that the common rotor shaft is filled in an area of the common flexible rotor shaft that is positively received in a rotor, e.g. its hollow rotor shaft. For this purpose, for example, a pin can preferably be inserted into it in a positively locking and/or materially locking manner. The hollow area of the common flexible rotor shaft inside the rotor can also be filled/cast with a casting agent.

A preferred development provides that the housings of adjacent drive units are each connected in a rotationally fixed manner by a flexible, liquid-tight hollow element. Such an element can preferably be a flexible tubular or hose-shaped, liquid-tight element. This element preferably has a smaller cross-section than the housing of the drive unit. The liquid-tight element can be formed, for example, from a plastic, in particular an elastomer. The liquid-tight element can be connected to the housing, in particular to a respective end wall of the housing, e.g. by means of a material bond.

Another preferred development provides that the housings of adjacent drive units are connected in a rotationally fixed manner by a common, continuously flexible, liquid-tight hollow element, in particular a tubular or hose-shaped hollow element, which surrounds the housings radially on the outside. The material chosen for the element can again be a plastic, e.g. elastomer. All drive units are preferably located inside this element. By connecting the element radially on the outside to the respective housing, the element loses the effectiveness of its flexibility, preferably locally in the area of this connection.

Another preferred development provides that the housings of adjacent drive units are connected in a rotationally fixed manner by a common hollow element, in particular a tubular element, which is partially rigid in the area of the drive units, in particular in the area of their housings, and partially flexible in the area between the drive units, in particular between their housings, and which surrounds the housings radially on the outside or forms part of the housings in the rigid area.

The common hollow element is preferably formed by a tube with a liquid-tight coating on the radial outside, which is made flexible in a respective section between adjacent drive units by material processing, e.g. at least one incision, preferably a spiral/helical incision or several incisions, in particular as previously described for the rotor shaft.

Accordingly, it is preferably provided that the liquid-tight coating covers the region of the pipe which has been made flexible by material processing, in particular the region of the pipe provided with at least one incision, in particular incisions, in a liquid-tight manner.

In these aforementioned embodiments, it is preferably provided that a flexible connecting element connecting respectively adjacent rotors is passed through the hollow element.

Furthermore, it is preferably provided that electrical connecting lines between the stators of adjacent drive units are guided through the hollow element, in particular within its wall. These electrical connecting lines preferably serve as control signal lines in order to electrically control the stators and set the drives in rotation. The wiring of the individual drive units to one another can also be carried out in such a way that the lines run inside the common outer flexible tubular element and leave the previous drive unit at the front and enter the subsequent drive unit at the front. In particular, the bearing point is as in 9 to be seen radially outside the stationary outer ring.

In the embodiments of the invention with the hollow element, in which at least some, preferably all drive units of the drive are arranged, it is preferably provided that a rotationally fixed connection between the common hollow element and the respective housing is formed by a material connection and/or positive connection and/or frictional connection between the radially outer wall of the respective housing and the inner wall of the common element.

A material bond is preferably formed by an adhesive bond between the radially outer wall of the housing and the inner wall of the common hollow element.

A force-locking connection is preferably formed by shrinking the common hollow element onto the housing.

A positive connection is preferably formed by projections or pockets/recesses on the radially outer wall of the housing, which at least partially penetrate into the common hollow element, in particular its inner wall, or by recesses in the radially outer wall of the housing, into which the common liquid-tight element at least partially penetrates.

In this description of the invention, rigid or stiff is preferably understood to mean that the element referred to as rigid is not bendable or deformable under normal conditions of use, i.e. it retains its geometric design.

Flexible is preferably understood to mean that the element referred to as flexible, e.g. a flexible connecting element, is deformable under normal conditions of use, in particular is bendable, preferably is reversibly deformable as often as desired.

The element described as flexible can preferably be straight in a relaxed state, i.e. when no forces act on it. Due to the flexibility, the element can be bent / curved out of this state by acting forces, whereby it preferably automatically returns to the relaxed state when the forces are removed.

However, a flexible element can also be inherently stable or indifferent in any possible form state, in particular it can have any indeterminate shape.

In particular, it can be provided that at least some, in particular all, elements referred to as flexible are shaped in a relaxed state, i.e. when no forces act on them, such that the entire cardiac catheter pump in the relaxed state assumes a shape, in particular a curved shape, that corresponds to the shape in later use, e.g. in the aortic arch. In particular, forces on the vessel walls can be reduced/eliminated in this way during use. It can then be provided that the cardiac catheter pump must be deformed from the relaxed shape into a shape that is at least essentially straight or follows the curvature of the vessel in order to be inserted into a vessel and to propagate in a vessel.

In order to achieve a bending line suitable for the entire cardiac catheter pump according to the invention, which enables movement of the cardiac catheter pump through the aortic arch, it can be provided that rigid parts and flexible parts of the rotor shafts or the shafts connecting them are in a certain ratio to one another.

The current state of the art and embodiments of the invention are described in more detail with reference to the following drawings.

The 1 shows the current state of the art. It shows a section of a human heart, into which a previously known cardiac catheter pump has been inserted through the aortic arch.

This cardiac catheter pump comprises a flexible cannula 1, which has an inlet area 2 at its distal end through which blood from the heart chamber can enter the cannula 1. At the proximal end of the cannula 1 there is a pump housing 3 in which an impeller 4 is arranged so as to be rotatable. The pump housing 3 also has an outlet area 5 from which the impeller can pump the blood from the cannula 1 into the aortic arch when the impeller is set in rotation by the drive 6 adjacent to the pump housing.

Based on the slight curvature in the 1 it can be seen that the cannula 1 is flexible and can therefore be bent. The arrangement of the pump housing 3 and drive 6, on the other hand, is not bendable/flexible and its length represents the so-called rigid length of the cardiac catheter pump, i.e. the length over which no bending is possible. This rigid length must not exceed a certain maximum length so that the cardiac catheter pump can be guided through the aortic arch with its non-bendable part.

This directly means that the drive 6 must not exceed a certain length, which means that the maximum possible electrical power of the drive is also limited.

The here for 1 The cardiac catheter pump according to the invention also has the elements described, the invention being based on the special design of the drive 6.

The 2 shows an embodiment of the cardiac catheter pump according to the invention. According to the enlarged detail, it can be seen that the drive 6 in the embodiment according to the invention is formed by several drive units 6a-d, which are arranged one behind the other, with adjacent drive units 6a/6b or 6b/6c or 6c/6d being flexibly connected to one another. Due to this flexibility in the connection to one another, the adjacent drive units 6a-d can be moved relative to one another, in particular at least substantially while maintaining the distance between the drive units.

The sequential arrangement of drive units 6a-d can therefore not only take on a straight-line configuration, as is the case with the drive of the prior art, but can also be bent. The sequential arrangement of drive units 6a-d can therefore be adapted to the curved course of the aortic arch or other lumens of vessels.

By dividing the entire drive into several flexibly connected drive units, it is possible to make the drive longer than is currently the case with the state of the art, because this does not increase the rigid length of the cardiac catheter pump.

The extended drive therefore also allows for greater electrical power or greater torque to be achieved in the drive, because the rigid length, which is now only given by the length of the housing of a respective drive unit or the longest of all drive units, no longer limits the overall length of the drive. The electrical power and/or torque of all individual drive units 6a-d add up to a total.

In particular, the construction starting from the pump housing in the direction of the distal end of the cannula 1 can essentially correspond to the constructions known to date in the prior art.

The 2 shows an embodiment of the invention in which the distal drive unit 6a of all drive units 6a-d together with the pump housing 3 forms a unit, in particular a rigid unit, ie the pump housing and distal drive unit 6a are rigidly connected to one another.

The drive unit 6a and the pump housing 3 can be housed in a common housing or alternatively are at least rigidly connected. In this embodiment, the unit consisting of the drive unit 6a and the pump housing 3 can define the maximum rigid length of the cardiac catheter pump.

In contrast, the 3 another embodiment of the invention, in which the distal drive unit 6a of all drive units 6a-d does not form a unit with the pump housing 3, in particular is flexibly connected.

The rigid length of this design can be compared to the design of the 2 Preferably, the lengths of the drive units are the same in all possible designs, but they can also be different.

For all possible embodiments shown and not shown, it is preferred that each drive unit 6a-d comprises a housing 7 with a stator 8 arranged in the housing 7 in a rotationally fixed manner and a rotor 9 rotatably mounted in the housing, in particular wherein the stator 8 and rotor 9 interact electromagnetically to drive the rotor 9, wherein the housings 7 of all drive units 6a, 6b, 6c, 6d are connected to one another in a rotationally fixed manner and axially flexibly and the rotors 9 of all drive units 6a, 6b, 6c, 6d are connected to one another in a rotationally fixed manner and, in particular at least outside the housings 7, axially flexibly. The stator and rotor thus preferably form an electric motor, wherein the stator can have coil windings that can be energized. In principle, however, other drive principles can also be implemented between the stator and rotor. The type of operation of the drive is not essential for the invention.

The 4 shows a first possible embodiment of executing the adjacent drive units 6a-d and connecting them flexibly.

In this design, each drive unit 6a-d has its own rigid rotor shaft 10). Such a rigid rotor shaft 10 can be made from a solid material or from a rigid tube. The rotor shaft 10 is - as in all possible designs - rotatably mounted on both ends of the rotor.

These rigid rotor shafts 10 of adjacent drive units 6a-d are in the 4 flexibly connected in that a section of a flexible, in particular bendable, shaft is arranged between the mutually facing ends of the rigid rotor shafts 10. Such a bendable shaft can be designed in a generally known manner, e.g. as a helically wound wire. The section of the bendable shaft 11 can be attached to the respective free end of the rigid rotor shaft 10 so that the rotor shafts are connected in a rotationally fixed but flexible manner. This attachment can be designed in a form-fitting and/or force-fitting and/or material-fitting manner.

The 5 shows an embodiment in which the flexible connection between the rigid rotor shafts 10 of adjacent drive units is designed by joints 12, in particular cardan joints 12, as a flexible connecting element. Otherwise, the design of the 5 to 4 identical. The joints represent a flexible connecting element that has no preferred shape, especially no relaxed state.

The 6 shows an embodiment according to which the rotors 9 of adjacent drive units 6a-d all have a common rotor shaft 13, preferably a one-piece rotor shaft 13, wherein the common rotor shaft 13 is rigid in a respective section 13a within a drive unit 6a-d and is flexible in a respective section 13b between adjacent drive units 6a-d.

In the embodiment shown, the common rotor shaft 13 is preferably formed by a tube which is made flexible in a respective section 13b between adjacent drive units 6a, 6b, 6c, 6d by material processing, here by incisions, particularly preferably spiral-shaped incisions 13c, so that the flexible section acts like a flexible connecting element.

The 7 shows an embodiment in which the rotors 9 of adjacent drive units 6a-d all have a common rotor shaft 13, in particular a one-piece rotor shaft 13, wherein the common rotor shaft 13 is designed to be flexible throughout, in particular as a flexible connecting element, and is received in a respective rotor 9 in a form-fitting and/or material-fitting manner, here preferably in a hollow rotor shaft 14.

In an area of the common rotor shaft 13 which is received in a rotor 9 in a form-fitting manner, the common rotor shaft 13 is preferably filled, e.g. by a pin 13d which is inserted into it in a form-fitting and/or material-fitting manner. Alternatively, the common rotor shaft can be filled with a casting agent. Within the rotor, the flexible effect of the actually continuously flexible common rotor shaft is thus locally canceled out.

The statements of the 4 to 7 Preferably have identical features except for the different designs of the flexible connections or the different designs of the rotor shafts.

For all versions of the 4 to 7 The housings 7 of adjacent drive units 6a-d are each connected in a rotationally fixed manner by a flexible, liquid-tight hollow element 15, in particular a flexible tubular or hose-shaped, liquid-tight element 15. In the embodiments shown of the 4 to 7 the flexible, liquid-tight hollow element 15 has a smaller cross-section than the housing 7. The cross-section is viewed perpendicular to the connection direction of adjacent drive units.

The flexible connecting element 11, 12, 13, 13b connecting the respective adjacent rotors 9 is guided through the hollow element 15, which also applies to subsequent embodiments of the other figures.

The 8 to 11 further show designs in which the housings 7 of adjacent drive units 6a-d are each connected in a rotationally fixed manner by a common, continuously flexible, liquid-tight hollow element 15, in particular a tubular or hose-shaped hollow element 15, which surrounds the housings 7 radially on the outside. All housings 7 of all drive units 6a-d or all drive units 6a-d are preferably arranged in the same common element 15.

According to the 8 The common hollow element can be, for example, a flexible hose which is connected to the housings 7 in a force-fitting manner, e.g. by shrinking. The shrinking creates a slight constriction in the cross-section between the adjacent housings 7.

The 9 shows an embodiment in which the housings 7 of adjacent drive units 6a-d are connected in a rotationally fixed manner by a common hollow element 15, in particular a tubular element 15, which is rigid in sections in the area of the drive units 6a-d, in particular in the area of their housings 7, and flexible in sections in the area between the drive units 6a-d, in particular of their housings 7, and which surrounds the housings 7 radially on the outside. Here, the embodiment is such that in the rigid area, the element 15 even forms part of the housings 7, in particular to which the respective stator is directly adjacent.

The common hollow element 15 is formed here by a tube with a liquid-tight coating on the radial outside, which can preferably be formed from an originally continuous rigid tube, which is made flexible in a respective section between adjacent drive units 6a-d by material processing, in particular incisions 15a, preferably spiral-shaped incisions 15a. The coating seals the otherwise continuous incisions 15a.

The coating is arranged at least over the incisions 15a or generally over the area of material processing in order to seal this area, but can also be applied over the entire length of the element 15.

The 10 shows an embodiment in which a positive connection is formed between the hollow element 15 and the outer wall of the housing 7 of each drive unit by projections 17 on the radially outer wall of the housing 7, which at least partially penetrate into the common element, in particular its inner wall. For this purpose, the material of the hollow element 15 preferably has a lower hardness than the material of the outer wall of the housing with the projections. For example, the material of the hollow element 15 can be made of plastic and the housing 7 of metal. It can preferably be provided that such projections extend at least partially in the circumferential direction on the wall of the housing 7, particularly preferably wherein these projections have an axial slope in their extension.

The 11 shows a further variant in which the hollow element 15 is integrally connected to the outer wall of the housing 7 by an adhesive bond 18.

The 8 to 11 show flexible connections between the rotors 9 of adjacent drive units with a section of a flexible shaft 11 that connects to rigid rotor shafts 10. This corresponds to the design of 4 . It should be noted here that - contrary to what has been presented - the statements of the 8 to 11 on with the shafts and rotor designs according to the 5 to 7 can be trained.

All versions of the flexible rotor connections used in the 4 to 7 can accordingly also be used with all the different designs of the flexible hollow elements 15 shown in the 8 to 11 shown and completely enclosing the housing 7 on the outside, can be combined as desired.

For all versions, the following applies: 4 to 7 shown - electrical connecting lines 16 between the stators 8 of adjacent drive units 6a-d are guided through the hollow element 15, in particular within its wall. The lines are in the 8 to 11 not or not fully visualized, but also present.

Overall, all designs provide flexibility within the drive, which according to the invention is formed by several drive units arranged axially one behind the other. One behind the other means one after the other in the connection direction, in particular in the direction from proximal to distal.

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions.

Cited patent literature

• DE 10336902 B3 [0003]

Claims (9)

Cardiac catheter pump comprising a. a preferably flexible cannula (1) which has an inlet region (2) at its distal end and a pump housing (3) with an impeller (4) and an outlet region (5) at its proximal end, in particular wherein blood can be conveyed from the inlet region (2) to the outlet region (4) by rotation of the impeller (4), and b. a drive (6) connected to the pump housing (3), with which the impeller (4) can be set in rotation in the pump housing (3), characterized in that c. the drive (6) comprises a series arrangement of several drive units (6a, 6b, 6c, 6d) which are flexibly connected to one another. Cardiac catheter pump according to Claim 1 , characterized in that the distal drive unit (6a) of the series arrangement comprises the pump housing (3) or is rigidly connected to the pump housing (3). Cardiac catheter pump according to Claim 1 , characterized in that the distal drive unit (6a) of the series arrangement is flexibly connected to the pump housing (3). Cardiac catheter pump according to one of the preceding claims, characterized in that each drive unit (6a, 6b, 6c, 6d) comprises a housing (7) with a stator (8) arranged in the housing (7) in a rotationally fixed manner and a rotor (9) rotatably mounted in the housing, in particular wherein the stator (8) and rotor (9) interact electromagnetically to drive the rotor (9), wherein the housings (7) of all drive units (6a, 6b, 6c, 6d) are connected to one another in a rotationally fixed and flexibly manner and the rotors (9) of all drive units (6a, 6b, 6c, 6d) are connected to one another in a rotationally fixed manner and, in particular at least outside the housings (7), flexibly. Cardiac catheter pump according to Claim 4 , characterized in that the rotors (9) of adjacent drive units (6a, 6b, 6c, 6d) a. each have their own rigid rotor shaft (10) and the rotor shafts (10) of adjacent drive units (6a, 6b, 6c, 6d) are flexibly connected, in particular by a section of a flexible shaft (11) or by joints (12), in particular cardan joints (12), as a flexible connecting element, or b. all have a common rotor shaft (13), preferably a one-piece rotor shaft (13), wherein the common rotor shaft is rigid in a respective section (13a) within a drive unit (6a, 6b, 6c, 6d) and is flexible in a respective section (13b) between adjacent drive units (6a, 6b, 6c, 6d), in particular the common rotor shaft is formed by a tube which is flexible, in particular as a flexible connecting element, in a respective section (13b) between adjacent drive units (6a, 6b, 6c, 6d) by material processing, preferably by at least one incision, preferably incisions, particularly preferably at least one spiral-shaped or helical incision (13c) or incisions (13c), or c. all have a common rotor shaft (13), in particular a one-piece rotor shaft (13), wherein the common rotor shaft (13) is designed to be flexible throughout, in particular as a flexible connecting element, and is received in a respective rotor (9) in a form-fitting and/or material-fitting manner, in particular in a hollow rotor shaft (14), preferably wherein in a region of the common rotor shaft (13) which is received in a form-fitting manner in a rotor (9), the common rotor shaft (13) is filled, preferably a pin (13d) is inserted into it in a form-fitting and/or material-fitting manner or the common rotor shaft is filled with a casting agent. Cardiac catheter pump according to Claim 4 or 5 , characterized in that the housings (7) of adjacent drive units (6a, 6b, 6c, 6d) a. are each connected in a rotationally fixed manner by a flexible, liquid-tight hollow element (15), in particular a flexible tubular or hose-shaped, liquid-tight element (15), preferably which has a smaller cross-section than the housing (7), or b. are connected in a rotationally fixed manner by a common, continuously flexible, liquid-tight hollow element (15), in particular a tubular or hose-shaped hollow element (15), which surrounds the housings (7) radially on the outside, or c. by a common hollow element (15), in particular a tubular element (15), which is rigid in sections in the area of the drive units (6a, 6b, 6c, 6d), in particular in the area of their housings (7), and flexible in sections in the area between the drive units (6a, 6b, 6c, 6d), in particular between their housings (7), which surrounds the housings (7) radially on the outside or forms part of the housings (7) in the rigid area, preferably wherein the common hollow element (15) is formed by a tube with a liquid-tight coating on the radial outside, which is flexible in a respective section between adjacent drive units (6a, 6b, 6c, 6d) by material processing, preferably at least one incision, in particular spiral or helical incision/incisions (15a), in particular wherein a respective adjacent rotors (9) connect the flexible connecting element (11, 12, , 13b) is passed through the hollow element (15). Cardiac catheter pump according to Claim 6 , characterized in that electrical connecting lines (16) between the stators (8) of adjacent drive units (6a, 6b, 6c, 6d) are guided through the hollow element (15), in particular within its wall. Cardiac catheter pump according to claim 6a or 6b, characterized in that a rotationally fixed connection between the common hollow element (15) and the housing (7) is formed by a material connection and/or positive connection and/or frictional connection between the radially outer wall of the housing (7) and the inner wall of the common element (15). Cardiac catheter pump according to Claim 8 , characterized in that a. a material connection is formed by an adhesive bond (18) between the radially outer wall of the housing (7) and the inner wall of the common element (15), and/or b. a frictional connection is formed by the common element (15) being shrunk onto the housing (7), and/or c. a positive connection is formed by projections (17) on the radially outer wall of the housing (7), which at least partially penetrate into the common element, or by recesses in the radially outer wall of the housing (7), into which the common element (15) at least partially penetrates.

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