FUNCTIONAL ELEMENT, IN PARTICULAR FLUID PUMP, HAVING A HOUSING AND A CONVEYING ELEMENT

Abstract

The invention relates to a fluid pump having a housing delimiting a fluid chamber and having a conveying element for the fluid disposed in the fluid chamber, the housing, with respect to the shape and/or size thereof, being able to be changed between at least a first, expanded state and a second, compressed state. The object, to stabilise adequately a corresponding housing, is achieved according to the invention by the housing having at least one stabilisation chamber which can be supplied with a fluid pressure and is different from the fluid chamber, the first state of the housing being assigned to a first fluid pressure in the stabilisation chamber and the second state of the housing being assigned to a second fluid pressure.

Claims

1-24. (canceled)

25. A fluid pump comprising: a catheter; a conveying element; an expandable housing defining an inner chamber configured to receive the conveying element, the housing coupled to a distal end of the catheter and being configured to transition between a compressed state and an expanded state within a blood vessel, the housing comprising: an outflow opening; an inflow opening positioned distal to the outflow opening; an inner wall; and an outer wall; and a one-way inflow valve configured to prevent fluid from flowing out of the inner chamber through the inflow opening, wherein the conveying element is disposed within the inner chamber and configured to be radially compressed by the inner wall when the housing is in the compressed state, and wherein the conveying element is further configured to pulsate to convey fluid from the inflow opening to the outflow opening when the housing is in the expanded state.

26. The fluid pump according to claim 25, wherein the fluid pump further comprises a one-way outflow valve configured to prevent fluid from flowing into the inner chamber through the outflow opening.

27. The fluid pump according to claim 26, configured such that, during operation of the pump, fluid is suctioned into the inner chamber through the inflow opening and expelled out of the inner chamber through the outflow opening.

28. The fluid pump according to claim 26, wherein the outflow valve comprises one or more valve flaps.

29. The fluid pump according to claim 25, wherein the inflow valve comprises one or more valve flaps.

30. The fluid pump according to claim 25, wherein the housing comprises the inflow valve.

31. The fluid pump according to claim 25, further comprising an elongate hose comprising a proximal end and a distal end, the proximal end of the elongate hose connected to the inflow opening of the housing and the distal end of the elongate hose configured to extend into a ventricle of a patient.

32. The fluid pump according to claim 31, wherein the elongate hose comprises the inflow valve.

33. The fluid pump according to claim 31, wherein the housing is configured to be positioned within an aorta and the elongate hose is configured to extend across an aortic valve.

34. The fluid pump according to claim 25, wherein at least one of the inner wall and the outer wall is configured to contract elastically from the expanded state into the compressed state.

35. The fluid pump according to claim 25, the fluid pump further comprising at least one expandable stabilization chamber, wherein the housing is configured to transition between the compressed state and the expanded state based on a change in inflation pressure of the at least one expandable stabilization chamber.

36. The fluid pump according to claim 35, wherein the at least one expandable stabilization chamber is disposed between the inner wall and the outer wall.

37. The fluid pump according to claim 35, wherein the at least one expandable stabilization chamber is configured to be supplied with a fluid pressure, wherein the compressed state of the housing corresponds to a first fluid pressure in the expandable stabilization chamber and the expanded state of the housing corresponds to a second fluid pressure in the expandable stabilization chamber, and wherein the second fluid pressure is higher than the first fluid pressure.

38. A fluid pump comprising: a catheter; a conveying element; an expandable housing defining an inner chamber configured to receive the conveying element, the housing coupled to a distal end of the catheter and being configured to transition between a compressed state and an expanded state within a blood vessel, the housing comprising: an outflow opening; an inflow opening positioned distal to the outflow opening; an inner wall; and an outer wall; and a one-way outflow valve configured to prevent fluid from flowing into the inner chamber through the outflow opening, wherein the conveying element is disposed within the inner chamber and configured to be radially compressed by the inner wall when the housing is in the compressed state, and wherein the conveying element is further configured to pulsate to convey fluid from the inflow opening to the outflow opening when the housing is in the expanded state.

39. The fluid pump according to claim 38, wherein the outflow valve comprises one or more valve flaps.

40. The fluid pump according to claim 38, wherein the housing comprises the outflow valve.

41. The fluid pump according to claim 38, further comprising an elongate hose comprising a proximal end and a distal end, the proximal end of the elongate hose connected to the inflow opening of the housing and the distal end of the elongate hose configured to extend into a ventricle of a patient.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0058] The invention is shown in a drawing and subsequently described with reference to an embodiment in the following.

[0059] There are thereby shown:

[0060] FIG. 1, an overview of the use of a fluid pump according to the invention in a blood vessel;

[0061] FIG. 2, a longitudinal section through a fluid pump with a compressed conveying element;

[0062] FIG. 3, a longitudinal section as in FIG. 2 with an expanded conveying element;

[0063] FIG. 4, a longitudinal section through a housing with stabilisation chambers;

[0064] FIG. 5, a cross-section through the construction according to FIG. 4;

[0065] FIG. 6, a longitudinal section through a housing having a further configuration of stabilisation chambers;

[0066] FIG. 7, a cross-section as indicated in FIG. 6;

[0067] FIG. 8, a longitudinal section through a hollow balloon-like housing in spheroid form;

[0068] FIG. 9, a longitudinal section through the functional element in total in compressed form;

[0069] FIG. 10, a fluid pump in longitudinal section having a pump rotor;

[0070] FIG. 11, in a side view, a hub-free rotor; and

[0071] FIG. 12, a detailed view of a pore structure.

DETAILED DESCRIPTION

[0072] FIG. 1 shows the functional element 1 in the form of a fluid pump in a section, inserted in the human body. The fluid pump is introduced by means of a hollow catheter 2 into a blood vessel 3 which leads to a ventricle 4. The housing 5 of the fluid pump is connected to the interior of the ventricle 4 via a suction hose 6 which extends through the blood vessel 3 and the suction hose there has one or more suction openings 7. The suction hose 6 is rounded off at its end in the vicinity of the suction openings 7 in order to avoid injuries to the interior of the heart.

[0073] Within the housing 5 of the fluid pump, a conveying element 8 in the form of a balloon is situated, in the present case essentially in cylindrical form, which balloon is connected via a pressure line 9 to a pressure source 10 outside the body. The pressure line 9 extends through the hollow catheter 2 and both are guided out of the blood vessel 3 to the outside of the body in a lock, not represented.

[0074] The pressure source 10 is shown only schematically in the form of a cylinder 11 and a piston 12 which is moveable therein, the piston producing, during a pulsating movement, a likewise pulsating pressure which leads to an alternating expansion and compression of the conveying element 8.

[0075] As a result, the conveying element 8 in the interior of the housing 5 takes up more or less space alternately so that, as a countermove, more or less space remains available for the fluid to be conveyed in the fluid chamber 13 of the housing 5. The fluid is hence expelled and suctioned in by the conveying element 8 in a pulsating manner.

[0076] By using valve flaps, the fluid flow is directed in the desired form. In the illustrated example, valve flaps 14 are provided in the suction line 6 and allow the fluid to flow in the direction of the arrow 15. The valve flaps could be provided equally well in the corresponding opening of the housing 5. Thereby involved is a return- or one-way valve which allows the fluid to flow in the direction of the arrow 15 but not to flow out in the opposite direction. This leads to the fact that, during compression of the conveying element 8, fluid, i.e. in particular blood, can be suctioned via this path, but that this cannot flow out again there during expansion of the conveying element.

[0077] Outflow flaps 16 which can be disposed for example directly on the housing 5 and which likewise allow the fluid to flow out in only one direction, namely in the direction of the arrow 17, are provided for the outflow.

[0078] With cooperation of the valve flaps 14, 16, it is ensured that the fluid is conveyed from the fluid pump only in the direction of the arrows 15, 17.

[0079] The throughput of the fluid pump is determined, apart from the residual power of the patient's heart as long as this is still functioning, by the pulsating frequency of the conveying element 8, on the one hand, and by the volume expelled respectively by the conveying element or by the free volume remaining in the fluid chamber 13. The conveyance is maximised when the conveying element can expand to completely fill the fluid chamber 13 and thereafter collapses so far that its interior is completely emptied. The conveying element can consist for this purpose of a highly elastic material which, after lowering the pressure in the pressure line 9, ensures compression of the conveying element. This leads to a pressure drop in the fluid chamber 13, as a result of which further fluid is suctioned subsequently.

[0080] However, it is a prerequisite for functioning of this mechanism that the housing 5 remains stable and does not collapse even when producing a low pressure in its interior. This requirement is connected, according to the invention, to the further requirement that the housing must be compressible for introduction and removal into and out of a body.

[0081] The invention provides for this purpose that the housing is provided with at least one stabilisation chamber which stiffens the housing as a result of pressure application.

[0082] In an extreme case, the entire housing can be configured thereby as a double-walled balloon, the space between the balloon walls being typically at a higher pressure, in the expanded state, than the space of the blood vessel surrounding the housing. It can also be provided that this pressure is higher than the pressure prevailing at most in the conveying element and in the fluid chamber.

[0083] FIG. 2 shows schematically the state of a fluid pump having a hollow cylindrical housing 5 and a compressed conveying element 8 in the suction phase. The fluid chamber 13 is essentially filled with the fluid flowing through the suction line 6.

[0084] The conveying element 8 has an essentially cylindrical form and consists for example of rubber or polyurethane or an elastomer with similar properties, the surface of the conveying element being able to be coated with a material which, on the one hand, prevents infections and, on the other hand, avoids accumulation of blood on the surface. The same coating can be provided in the interior of the housing 5 on the walls thereof.

[0085] The conveying element 8 is connected to a pressure source via a pressure line 9 which is essentially designed not to be expandable.

[0086] FIG. 3 shows the configuration of FIG. 2 in an expanded state of the conveying element 8 in which the free residual space of the fluid chamber 13 is minimised and the fluid/the blood can flow out of openings 18 of the housing 5 through valve flaps 16.

[0087] It should be noted than the housing 5 with respect to its outer diameter can be configured such that it does not completely fill the clear opening of the blood vessel 3 so that, when inserted into a body, blood can be conveyed through the vessel 3 by the inherent function of the heart, in addition to the fluid pump. However, it is also conceivable that the diameter of the blood vessel is completely filled by a suitably chosen diameter also for specific purposes.

[0088] In FIG. 4, the strengthening of the housing 5 by stabilisation chambers is dealt with in more detail. In this embodiment, a plurality of strand-shaped stabilisation chambers 19, 20 is aligned parallel to the longitudinal axis 21 of the housing 5 and disposed in the housing wall.

[0089] FIG. 5 shows a cross-section with seven such stabilisation chambers. The individual stabilisation chambers are separated from each other in this case and connected individually to a fluid pressure source via pressure lines 22, 23, 24. The stabilisation chambers can be supplied with pressure in order to stiffen the housing 5. In order to introduce or remove the housing 5, they are emptied so that the housing 5 can collapse on itself.

[0090] The stabilisation chambers can also be connected amongst each other via a pressure line in order to ensure that the same pressure respectively prevails in them and in order to simplify filling and emptying.

[0091] FIG. 6 shows another arrangement of the stabilisation chambers in the form of annular strands which are disposed respectively coaxially to each other and to the housing 5. The stabilisation chambers are designated with 25, 26. In the embodiment, four of these stabilisation chambers are provided equidistant from each other in the housing wall. They are connected to a pressure source 29 by means of pressure lines 27, 28.

[0092] Such annular or even possible, helical stabilisation chambers offer particularly good stiffening of the housing and, during pressure application, a corresponding resistance to the pulsating low pressure in the housing interior.

[0093] In the embodiment, the stabilisation chambers and the conveying element 8 are connected to the same pressure source 29 via a multi-way control valve 30. As a result, the pressure source 29 can be used both for filling the stabilisation chambers and for the pulsating pumping of the conveying element 8. FIG. 7 shows a cross-section through the housing represented in FIG. 6 in longitudinal section with a toroidal stabilisation chamber 26.

[0094] In FIG. 8, another concept of the housing within the scope of the invention is represented, in which the housing wall is double-walled, the two outer walls (balloon walls) have a very thin design and the housing is hence constructed in the manner of a balloon. The housing forms a double-walled balloon having a large cavity 31 which can however be subdivided into a plurality of partial chambers. Either thin intermediate walls are provided for this purpose or, if no complete subdivision is desired, also only individual reinforcing struts in the form of webs 32, 33 can be provided. These ensure that inner wall and outer wall of the balloon cannot perform shear movements relative to each other so that the housing 5 in total is stabilised. The interior 31 is connected to the pressure source 29 by means of a pressure line 34. The housing 5 has in total the contour of a spheroid.

[0095] The stabilisation struts 32, 33 can typically consist of the same material as the balloon walls of the housing 5 and be produced in one piece with the latter. The struts can thereby surround the housing 5 annularly or be configured as axis-parallel webs. However, also any orientation, for example even a grating-shaped structure, is conceivable.

[0096] Likewise, also in the above-described embodiments not only is the concretely described orientation of the strand-shaped stabilisation chambers conceivable but also a grating-shaped or network-shaped structure there which penetrates a solid housing wall.

[0097] In FIG. 9, finally the collapsed shape of the housing represented in FIG. 8 is shown, the spheroid being collapsed. The conveying element 8 must likewise be compressed of course for introducing/removing the fluid pump into a blood vessel.

[0098] For removal of the fluid pump from the vessel, it can provided that firstly the housing 5 is collapsed by reducing the pressure in the stabilisation chambers and only thereafter is the conveying element 8 emptied. As a result, an oblong shape is produced when the housing 5 is folded up and the latter is predominantly prevented from collapsing in the longitudinal direction and hence adopting a higher cross-section. The elastic contraction of the housing can thus also assist compression of the conveying element.

[0099] By means of the invention, a functional element is formed which is compressible to a high degree and nevertheless has the necessary stability in operation to resist both low and high pressures in a dimensionally stable manner during pulsating pumping.

[0100] In FIG. 10, a housing 5 similar to that represented in FIG. 9 is shown, which however surrounds a pump rotor here, which rotates about its longitudinal axis 40 and thereby conveys a fluid axially. The blades 41 can thereby be secured individually to branch off on a shaft 42 or also a helically circumferential blade can be provided. The rotor is radially compressible and can be manufactured for example from a framework comprising a memory alloy, for example Nitinol, or from another elastic material. The rotor can have open or closed cavities in the blades and/or the hub which are elastically compressible. In FIG. 10, the inner wall of the housing is designated with 46, the outer wall with 47. At least the inner wall can be widened and contracted elastically. A contracted state of the housing 5 is represented in broken lines and the inner wall is designated with 43. This presses the blades 41′, in the represented state, into a radially bent-in state so that the entire rotor is already reduced in size by some distance radially.

[0101] In FIG. 11, a hub-free rotor which can also be used is represented and consists of a helically bent flat plate. This can consist for example of an easily deformable or compressible material, such as for example a sheet metal grating covered with foil or a foam, the rotor which is represented as open-pore or closed-pore is hub-free and self-supporting, i.e. the blade itself transmits the torque and is only mounted outside rotatably and connected to a driveshaft 44 (FIG. 10) which extends through a hollow catheter 45.

[0102] FIG. 12 shows, in greatly enlarged, microscopic representation, a housing material in the form of a foam 132 having closed pores 128, 129, the material of the walls between the pores being configured, in a variant (cavity 128), as a semipermeable membrane.

[0103] Such a membrane allows the diffusion of specific liquids, which can be used for example for an osmotic effect. If the cavities/pores 128 are filled for example with a liquid in which a salt in a highly concentrated form is dissolved and if the foam is brought into a liquid which has a lower solution concentration, then the combination tends to bring the concentrations of both liquids to approximate to each other such that the solvent diffuses from outside into the interior of the cavity 128 through the membrane 130. As a result, an increased osmotic pressure is produced and can be used to pump up the cavity 128 into the shape represented in broken lines. As a result, an expansion and stiffening of the foam can be achieved.

[0104] This effect can also be used specifically for larger cavities in the housing. Alternatively, also swelling processes can be used to expand the rotor.

[0105] In connection with the cavity 129, a hose 131 is represented and symbolises that corresponding cavities can also be filled with a fluid via individual or collective supply lines or that such a fluid can be suctioned out of them in order to control corresponding decompression/compression processes.