EP2259810A1

EP2259810A1 - Heart support device

Info

Publication number: EP2259810A1
Application number: EP09727216A
Authority: EP
Inventors: Berndhard Vodermayer; Harald Wagner; Wolfgang Schiller; Thomas Schmid
Original assignee: Deutsches Zentrum fuer Luft und Raumfahrt eV
Current assignee: Deutsches Zentrum fuer Luft und Raumfahrt eV
Priority date: 2008-04-05
Filing date: 2009-04-03
Publication date: 2010-12-15
Also published as: US8834343B2; CA2757653A1; US20110137107A1; DE102008017448A1; WO2009121962A1

Abstract

The invention relates to a heart support device for pulsating delivery of blood (12) comprising a first (14) and a second (16) ventricle and a pump (18). Both ventricles (14, 16) comprises a fluid chamber (14a, 16a) and a blood-conveying chamber (14b, 16b), wherein each fluid chamber (14a, 16a) can be filled with a fluid (20) or emptied by way of the pump (18) in such a way that an expansion or contraction of the fluid chamber (14a, 16a) occurs. In an expansion of the fluid chamber (14a) of a ventricle (14), a compression of the blood-conveying chamber (14b) of the same ventricle takes place, wherein a rigid pressure plate (24) is disposed between a fluid chamber (14a, 16a) and the respective blood-conveying chamber (16a, 16b), said pressure plate able to move in the direction of the respective blood-conveying chamber (14b, 16b).

Description

Herzunterstützunqsvorrichtunq

The invention relates to a Herzunterstutzungsvorπchtung for pulsatile delivery of blood.

Cardiac assist devices, such as the Ventricuiar Assist Device (VAD), are implanted into a patient's body in heart failure. They take over part of the pumping work and thereby stabilize the circulation until, for example, a donor organization is available. Recent studies have shown that cardiac function can improve to the extent that deployment of a cardiac assist device is possible, allowing explantation of the system without subsequent heart transplantation.

Artificial heart pumps can be adapted to a wide variety of requirements and, in contrast to donor hearts, are available without a waiting period. However, in terms of the technique used, as well as the compatibility of the implants high demands on Herzuπterstützungsvorrichtungen. For example, the blood can be damaged by the pumping work. The supply of electrically operated systems, for example with cables through the abdominal wall, carries a high risk of infection for the patient. Low efficiencies also require high energy consumption and heat the surrounding tissue. Often the assisted circulation of the blood must be maintained for months or years. The systems are subject to heavy mechanical loads. There A rapid change of blood pumps is not possible, they must have a very high failure safety.

DE 94 201 20 describes a cardiac assist system which is operated hydraulically. A positive displacement pump alternately pumps a hydraulic fluid into a first and a second hydraulic chamber, wherein the hydraulic fluid is separated from the blood to be delivered in the hydraulic chamber via a flexible membrane. By filling the first hydraulic chamber with hydraulic fluid, the blood located there is displaced and conveyed via a valve into the circulation. The hydraulic pump is arranged between the two hydraulic chambers and partly in the hydraulic chambers themselves.

A disadvantage of the device described is that the two hydraulic chambers to which laterally connect two blood chambers, as well as the arranged between the hydraulic chambers hydraulic pump together have a large height and therefore can be very difficult implanted into the body of a patient.

The object of the invention is to provide a cardiac assist device which has a low overall height.

The object is achieved by the features of claim 1 and 11, respectively.

A cardiac assist device for pulsatile delivery of blood has a first and a second ventricle and a pump. Each of the ventricles has a fluid chamber and a blood-carrying chamber, wherein each fluid chamber can be filled or opened by the pump with a fluid such that expansion or contraction of the fluid chamber occurs.

In the fluid chamber, preferably no blood is present. According to the invention, upon expansion of the fluid chamber of a ventricle, compression of the biotractive chamber of the same ventricle occurs. This can be done conveying blood into the bloodstream, with both the left and the right ventricle can be supported. A Volumeπausgleichsbehälter to compensate for the volume delivered is not required.

According to the invention, the pump is arranged outside the first and the second fluid chamber and / or outside the first and the second ventricle.

This makes it possible to place or implant the pump and the two ventricles at different locations in or on the body of a patient. For this purpose, the pump may preferably be connected to the fluid chambers via a fluid line of corresponding length. The device according to the invention thus has a lower overall height and can be implanted in the body of smaller patients without problems.

Preferably, the first and second ventricles are arranged adjacent to each other and have, for example, a common partition wall. In particular, the two ventricles can adjoin one another exclusively via an intermediate wall.

Due to the inventive design of the

Cardiac assist device, it is possible to arrange the pump at a distance to the two ventricles and / or to the fluid chambers. This distance can be, for example, greater than 10 cm or more preferably greater than 15 cm. This makes it possible to accommodate the drive pump in a separate from the heart pump electronics housing in which, for example, batteries for the operation of the pump and electronics are housed for control. The advantage here is the minimization of the Volumes of implanted components. In this way, a full implantability of the components is favored. In particular, the pump can be arranged seitüch next to the first and the second ventricle. An arrangement above or below the two ventricles is also possible. For example, the two ventricles can be arranged laterally offset from one another on the left and right, wherein they are preferably immediately adjacent, that is, adjacent to one another. In this case, the pump may be connected via a fluid line with the two ventricles and, for example, be arranged cranially over the two ventricles, that is, relative to the ventricles. Thus, preferably, the pump is not disposed between the first and second ventricles and / or not between the first and second fluid chambers.

The fluid delivered by the pump is preferably a hydraulic fluid, the fluid not being the blood of a patient within the meaning of the invention. Rather, it is, for example, a liquid, by which a conveyance of the blood is caused by a corresponding contraction of the blood-carrying chambers.

In a particularly preferred embodiment, the intermediate wall, by which the two ventricles are separated from each other, is arranged stationary relative to the cardiac assist device. This means that the intermediate wall is not displaceable during an expansion of the fluid chamber, so that an expansion of the fluid chamber causes a compression of the blood-carrying chamber and thus a transport of blood into the bloodstream.

The intermediate wall may preferably be made of the same material as the ventricles themselves. For example, the two pumping chambers and the dividing wall can be manufactured in a single finishing process and later easily integrated into an enclosing housing. The common wall, that is the intermediate wall, is preferably made somewhat thicker in relation to the ventricular walls, so that their Stiffness can be increased. Despite the greater thickness, the intermediate wall is preferably flexible. In this way, on the one hand, a certain flexibility in the pumping operation can be achieved, so that a soft ejection of the blood can take place. As a result, the pump is spared and the service life of the system increased Femer can be achieved by a flow-optimized flow in the pumping chambers. In addition, the system can be made even more compact, so that the Biutleitungen to and from the heart can be kept as short as possible. Thus, an implantation site near the heart can be selected. The membrane in the described embodiment is preferably elastic.

The fluid chambers may each be separated from the blood-carrying chambers by a flexible expansible membrane. The membrane is preferably double-layered, wherein between the two layers of the membrane, a liquid-filled gap for reducing the friction between the two layers may be formed. The gap may be filled with silicone oil, for example.

An independent invention also relates to a

Heart support device for pulsatile delivery of blood with a first and a second ventricle, and a pump. According to the invention described so far, both ventricles each have a fluid chamber and a blood-carrying chamber, wherein each fluid chamber can be filled or emptied by the pump with a fluid in such a way that expansion or contraction of the fluid chamber occurs. Upon expansion of the fluid chamber of a ventricle, compression of the blood-carrying chamber of the same ventricle occurs. An essential feature of the second invention is that in each case between a Fiuidkammer and the respective blood-carrying chamber in the direction of the respective blood-carrying chamber displaceable preferably rigid pressure plate is arranged. The fluid chamber can be designed as bellows, squib or balloon. By the pressure plate takes place during an expansion of the fluid chamber, a compression of the respective bSutführenden chamber.

The pressure plate may in this case have a surface which is larger than the base surface of the fluid chamber, so that the volume of the fluid in a completely expanded fluid chamber is smaller than the volume of the pumped blood. By using a preferably rigid pressure plate, it is thus possible to promote a larger Bfutvolumen with a smaller amount of fluid. There is a translation of the pressure and the volumes. The cardiac assist device according to the second invention may have all the features of the first invention. In particular, a stationary and reinforced intermediate wall can be arranged between the two ventricles.

In a preferred embodiment, the fluid chamber has rigid sidewalls which are perpendicular to the pressure plate to avoid evasion of the sidewalls by the applied pressure. The connection between the two side walls, that is to say the side of the fluid chamber pointing in the direction of the pressure plate, can be flexible and stretchable.

For example, the steps of the squib may form on average a jam-like structure which expands by the fluid pressure and thus presses on the pressure plate like a telescope

The squib may further be a balloon which is spherical and has a smaller volume than the blood chamber. The balloon has only the same diameter as the width of the blood chamber viewed in cross-section from the side. Both the cardiac assist device of the first and second invention may further include the features described below. It can be provided rigid housing walls, between which the ventricles are arranged. The first and the second blood-carrying chamber can furthermore be designed to be flexible and in particular expandable.

In a particularly preferred embodiment, the ventricles are rigid, wherein the Fiuidkammerπ are separated by an elastic membrane of the respective blood-conducting chamber of a stiff ventricle. The volume of the first and the second blood-carrying chamber can thus be increased in particular by a negative pressure in the respective fluid chamber by an elastic deformation of the elastic membrane. Particularly preferred is the volume of the first and the second biutführenden chamber after its caused by the negative pressure increase by a Eϊgenspannuπg the elastic membrane can be reduced in particular without the use of an overpressure in the respective fluid chamber.

Preferably, the shape of the stiff ventricle is selected such that flow optimization can be achieved. When using cardiac assist devices, it is important to avoid areas in the ventricles in which there is little or no blood movement, as this promotes the formation of thrombi. It is thus important to achieve optimized flow in the blood-carrying chamber and in the conduits. This can be achieved by the rigid ventricle having a flow-optimized shape, ie a shape that promotes blood flow. What is essential here is that the membrane which separates the fluid chamber from the blood-carrying chamber is elastic, so that in the filled state of the blood-carrying chamber it lies essentially completely against the inner wall of the rigid ventricle and thus has the flow-optimized shape of the rigid ventricle. When the blood is ejected, its elasticity reduces the surface of the membrane, so that in their relaxed state, no kinks or distortions in the membrane, which could adversely affect the Biutströmung.

The embodiment just described can also be operated by means of a hydraulic actuation, wherein the btutfuhrende chamber can be increased by a negative pressure and the blood can be ejected by a generated by a hydraulic fluid pressure again. In addition, the residual stress of the elastic membrane can also be used to eject the blood.

Preferably, the fluid chamber of the first ventricle and the fluid chamber of the second ventricle are alternately filled with fluid by the pump and entieerbar.

For refilling diffused fluid, a refill port can be provided, which can be reached from outside the patient's body, for example via a syringe.

In all of the described cardiac assist devices, electrical pumps known in the art may be used. It is advantageous that the electric pumps have a low overall height and a high mileage.

In the following, preferred embodiments of the invention will be explained with reference to figures.

Show it :

1 is a schematic view of a first embodiment of the cardiac assist device according to the first invention, Fig. 2 is a schematic view of the first ventricle of

Embodiment according to FIG. 1,

FIGS. 3a and 3b are schematic views of an embodiment of the cardiac assist device according to the second invention;

FFGn. 4a and 4b are schematic views of another embodiment of the cardiac assist device according to the first invention, and

Fig. 5 is a schematic view of a Squibs.

Referring to Fig. 1, a cardiac assist device for pulsatile delivery of blood 12 has a first 14 and a second 16 ventricles. Every ventricle! has a fluid chamber 14a, 16a and a blood-carrying chamber 14b, 16b. The Fiuidkamrnern are filled with a hydraulic fluid. The FSuidkammer 14 a is connected to the pump 18 via the fluid line 38 a. The Fiuidkammer 16 a is connected via the Fiuidieitung 38 b to the pump 18. By means of the pump 18, hydraulic fluid is alternately pumped into the first and second fluid chambers 14a, 16a, so that there is an alternation of an expansion of the two fluid chambers 14a, 16a. Upon expansion of the fluid chamber 14a of the ventricle 14, a compression of the blood-carrying chamber 14b of the same ventricle 14 takes place. The same applies to the second ventricle 16,

The pump 18 is disposed outside of the first and second ventricles 14, 16 and outside the first and second fluid chambers 14a, 16a. According to FIG. 1, the pump 18 is arranged, for example, to the right next to the two ventricles 14, 16. It is thus laterally offset next to the ventricles 14, 16. However, the ventricles 14, 16 can also instead As in Fig. 1 one above the other, be arranged side by side in the body of a patient, so that the pump 18 may be arranged, for example, above or below the ventricles 14, 16.

According to FIG. 1, the two ventricles 14, 16 are arranged adjacent to one another, wherein they are separated by a stationary intermediate wall 22. The cardiac assist device is bounded by a first and a second housing wall 32, 34.

The Fluϊdkammerπ 14a, 16a and the blood-carrying chambers 14b, 16b are separated by a respective double-layered membrane 13.

FIG. 2 shows a side view of the first ventricle 14 from FIG. 1. The blood-carrying chamber 14b has a blood inlet line 15a and a blood outlet line 15b, which are connected to blood vessels of the patient when the heart support device is implanted. The conduits 15a, 15b may include valves for controlling blood flow.

In a second invention according to FIGS. 3 a and 3 b, a rigid pressure plate 24, which is displaceable in the direction of the respective blood-conducting chamber 14 b, 16 b, is arranged in each case between a fluid chamber 14 a, 16 a and the respective blood-carrying chamber 14 b, 16 b. In FIGS. 3 a and 3 b, only the first ventricle 14 is depicted here, wherein the second ventricle 16 is designed to form the first ventricle 14 under the housing intermediate wall 22.

In the illustrated embodiment, the fluid chamber 14a is formed as a squib. As shown in Fig. 5, the squib having an arbitrarily shaped base such as an accordion or a bellows may be constructed. The folds are made of a tensile material to allow expansion only in the direction of its longitudinal axis. One Expansion in the other two directions is prevented. In the unexpanded state, the squib is flat, but its footprint is not significantly increased. Via the hydraulic line 38a, which is mounted on the side of the squib 14a near its bottom surface, compressed air or a hydraulic fluid can be supplied. The expansion of the squib allows the application of a force F to a target object. The squib 14a is connected to the pump 18 via the hydraulic line 38a, and when squirting hydraulic fluid into the squib 14a, expansion of the squib takes place. As a result, the rigid pressure plate 24 is pressed in the direction of the Bfutführenden chamber 14, so that the blood-carrying chamber 14 b is compressed. Since the squib 14a has a footprint smaller than the area of the pressure plate 24, the volume of hydraulic fluid 20 needed for expansion of the squib 14a is smaller than the volume of the pumped blood 12. The pressure plate 24 may also be in the distal end of the squib 14a be integrated. In Fig. 5, an unexpanded squib 14a is shown on the left side, while the right side shows an expanded squib 14a.

It is preferred that the squib 14a is formed as an undivided component, that is to say in one piece, so that no leakage problems arise. Compared to an actuator which is made up of a plurality of segments, the friction losses at the segment contacts can also reduce the mechanical efficiency cause the pump to be reduced. Preferably, the Squib 14a does not require bearings, gaskets, trains or the like to enable safe and efficient operation. When using a squib in the embodiments of the invention, it is possible to omit the pressure plate 24 so that the side or wall of the squib 14a facing the blood-carrying chamber 14b presses directly on the blood-carrying chamber 14b. Thus, the squib may be formed as part of the blood-conducting chamber 14b. The squib may also be designed such that its sectional area corresponds to the projection area of the blood-carrying chamber or the membrane. As a result, the force is evenly distributed to the blood-carrying chamber and it can be realized a small height of the device. Again, it is not necessary to provide a separate pressure plate. Preferably, the common wall between Squib and the blood-carrying chamber or membrane has a shape or surface that promotes blood flow.

The side walls 26, 28 of the Squibs 14a are perpendicular to the pressure plate 24 and are rigid, so that an expansion of the Squibs 14a can take place only in the direction of the blood-carrying chamber 14b. The side 30 of the fluid chamber 14a pointing in the direction of the pressure plate 24, which also points in the direction of the blood-carrying chamber 14b, is designed to be flexible and expandable.

In Fig. 3b, a compressed blood-carrying chamber 14b is shown.

FIGS. 4a and 4b show a further embodiment of the cardiac assist device according to the invention. Only one ventricle 14, which is stiff, is shown. By an elastic membrane 36, which is preferably bonded to the inner wall of the ventricle 14, the Fiuidkammer 14 a of the blood-carrying chamber 14 b of the rigid ventricle 14 is separated. The volume of the blood-carrying chamber 14b can be increased by a negative pressure of the fluid chamber 14a by elastically deforming the elastic membrane (see FIG. 4b). To generate a negative pressure in the fluid chamber 14a, the fluid is pumped out of the rigid ventricle 14 via the fluid line 38a, so that the pressure in the blood-carrying chamber 14b is higher than the pressure in the fluid chamber 14a. According to FIG. 4b, in this state, blood is supplied via the blood supply line 15a into the blood-carrying chamber 14b. After its enlargement caused by the negative pressure, the volume of the blood-carrying chamber 14b is reduced again. This is done by an internal stress of the elastic Membrane 36, so that the blood is pushed out via the Blutausiassleitung 15b from the blood-carrying chamber 14b.

In addition to a flow-favorable shape of the rigid ventricle 14, in order to avoid dead zones in the blood-carrying chamber 14b, it is important to find a suitable location at which the elastic membrane 36 is connected to the inner wall of the ventricle 14. The circumferential connecting line, at which the membrane 36 is connected to the inner wall of the ventricle 14, is. in this case arranged within the ventricle 14 such that no dead zones arise in the blood-carrying chamber 14b. For example, the elastic membrane 36 may be connected to the inner wall at the narrowest part of the ventricle 14. Preferably, the connection point is selected such that the elastic membrane 36 in the filled state of the blood-carrying chamber 14b runs tangentially to the outer wall of the blood inlet line 15a. The same applies to the bleed outlet line 15b. Since the rigid ventricle 14 has a constriction below the inlet and outlet lines 15a, 15b, it is particularly preferred that the membrane 36 be with the ventricle 14 at the apex of that constriction, ie at the narrowest point the ventricle 14 is connected, so that no dead zones in the blood-carrying chamber can arise above or below this connection line. It is preferred that the ventricle 14 is formed streamlined in that it has no undercuts and in particular has a round uniform shape.

Claims

claims

1. Heart support device for pulsatile delivery of blood (12), with

a first (14) and a second (16) ventricle and

a pump (18),

wherein both ventricles (14, 16) each have a Fluidkamrner (14a, 16a) and a blood-carrying chamber (14b, 16b) and each fluid chamber (14a, 16a) by the pump (18) with a fluid (20) so fillable or emptied is that an expansion or contraction of the fluid chamber (14a, 16a) takes place,

wherein the expansion of the fluid chamber (14a) of a ventricle (14) causes a compression of the blood-carrying chamber (14b) of the same ventricle (14),

characterized,

a preferably rigid pressure plate (24) which is displaceable in the direction of the respective blood-carrying chamber (14b, 16b) is arranged in each case between a fluid chamber (14a, 16a) and the respective biotractive chamber (14b, 16b).

2. Heart support device according to claim 1, characterized in that the fluid chamber (14a, 16a) is designed as a bellows, Squib or Baiion.

3. heart assist device according to claim 1, characterized in that by the pressure plate (24) during an expansion of the Fiuidkamrner (14a, 16a) takes place a compression of the jeweiiigen blood-carrying chamber (14b, 16b),

4. A cardiac assist device according to claim 1, characterized in that the fluid chamber (14a, 16a) has a base area which is smaller than the area of the pressure plate (24), so that the volume of the fluid (20) during an expansion of the fluid chamber ( 14a, 16a) is smaller than the volume of the pumped blood (12).

5. Cardiac assist device according to one of claims 1 to 4, characterized in that the fluid chamber (14a, 16a) has rigid side walls (26, 28) which run perpendicular to the pressure plate (24).

6. Cardiac assist device according to claim 5, characterized in that in the direction of the pressure plate (24) facing side (30) of the fluid chamber (14a, 16a) is flexible and stretchable.

7. Cardiac assist device according to one of claims 1 to 6, characterized by rigid housing walls (32, 34), between which the ventricles (14, 16) are arranged.

8. cardiac assist device according to one of claims 1 to 6, characterized in that the first and second blood-leading Chamber (14b, 16b) are flexible and in particular stretchable,

9. cardiac assist device according to one of claims 1 to 7, characterized in that the ventricles (14, 16) are formed stiff.

10. Herzuπterstützungsvorrichtung according to claim 9, characterized in that the Fiuidkammern (14a, 16a) by an elastic membrane (36) from the respective blood-carrying chamber (14b, 16b) of a rigid ventricle (14, 16) are separated, so that the volume the first and second blood-carrying chamber (14b, 16b) can be enlarged, in particular by a negative pressure in the respective fluid chamber (14a, 16a), by elastically deforming the elastic membrane (36).

11. Cardiac assist device according to claim 10, characterized in that the volume of the first and second blood-carrying chamber (14b, 16b) after its caused by the negative pressure increase by an internal stress of the elastic membrane (36), in particular without the use of an overpressure in the respective Fluid chamber (14a, 16a) can be reduced.

12. A cardiac assist device according to any one of claims 1 to 11, characterized in that the fluid chamber (14a) of the first ventricle (14) and the FSutdkammer (16a) of the second ventricle (16) by the pump (18) alternately with Ffuid (20) can be opened and opened,

,

13. Cardiac assist device according to one of claims 1 to 12, characterized by a Nachfύllport for refilling diffused fluid (20), the port being accessible from outside the body of a patient via a syringe,

14. Heart support device according to one of claims 1 to 13, characterized in that the membrane (13) is double-layered, wherein between the two layers of the membrane (13) a liquid-filled Spait is formed to reduce the friction between the two layers.

15. Herzunterstutzuπgsvorrichtung according to any one of claims 9 to 13, characterized in that the elastic membrane (36) at a narrowing of the ventricle (14, 16), in particular at the narrowest part of the ventricle (14, 16) is connected to the inner wall.

16. Cardiac assist device according to one of claims 9 to 15, characterized in that the elastic membrane (36) is designed such that in the filled state of the blood-carrying chamber (14b) substantially completely against the inner wall of the ventricle (14), so the blood-carrying chamber (14b) assumes the shape of the stiff ventricle (14) in this state