Abstract
A device (2) for providing circulatory assistance is provided and comprises a balloon (4) comprising a membrane defining a cavity having an internal volume (Vc), wherein the balloon comprises a proximal portion (4a) comprising a proximal end and a distal portion (4b) comprising a distal end. The device (2) further comprises a first catheter, affixed to the distal end of the balloon (4) at a first fixation point (P1) and a second catheter (8), affixed to the proximal end of the balloon at a second fixation point (P2). The second catheter (8) is configured for axial movement with respect to the first catheter or guide wire (6) between a first position in which the first and second fixation points (P1, P2) are spaced apart from each other in the longitudinal direction by a first distance (Dx), which is variable to bring about inversion of the balloon.
Claims
1. A device for providing circulatory assistance, the device comprising: a balloon comprising a membrane defining a cavity having an internal volume, wherein the balloon comprises a proximal portion comprising a proximal end and a distal portion comprising a distal end, and a longitudinal axis (A) extending between the proximal and distal ends; wherein the device further comprises: a first catheter or guide wire, affixed to the distal end of the balloon at a first fixation point (P1); a second catheter, affixed to the proximal end of the balloon at a second fixation point, the second catheter being arranged in a parallel or coaxially with respect to the first catheter or guide wire, wherein the second catheter is configured for axial movement with respect to the first catheter or guide wire between: a first position in which the first and second fixation points are spaced apart from each other in the longitudinal direction by a first distance, preferably in which the proximal portion of the balloon is not inverted with respect to the distal portion of the balloon; a second position in which the first and second fixation points are spaced apart from each other in the longitudinal direction by second distance, and in which the proximal portion of the balloon is inverted with respect to the distal portion of the balloon to form a receptacle having an internal volume.
2. The device according to claim 1, further comprising a locking mechanism, preferably a releasable locking mechanism, configured to lock the first catheter and second catheter or the guide wire and the second catheter in the second position with respect to each other.
3. The device according to claim 1, wherein a conduit is provided between the first catheter or guide wire and the second catheter, and wherein the conduit is provided in fluid communication with the internal cavity of the balloon.
4. The device according to claim 1, wherein the distal portion of the balloon is more rigid than the proximal portion of the balloon.
5. The device according to claim 1, further comprising one or more support structures, preferably one or more collapsible support structures, configured to support the distal portion of the balloon in an open configuration.
6. The device according to claim 5, comprising at least one support structure disposed within the internal volume of the balloon.
7. The device according to claim 5, comprising at least one support structure attached to or incorporated into an outer surface of the distal portion of the balloon.
8. The device according to claim 5, wherein the support structure comprises a shape-memory material.
9. The device according to claim 1, wherein the balloon comprises an elastic membrane, or an inelastic membrane.
10. The device according to claim 1, wherein: the proximal portion of the balloon and the distal portion of the balloon are formed of a continuous membrane; or wherein the proximal portion of the balloon is formed of a first membrane and wherein the distal portion of the balloon is formed of second membrane, and wherein the first and second membranes are joined.
11. A heart support device for circulatory assistance, the heart support device comprising: a receptacle having an internal volume, the receptacle extending from a rim defining an open proximal end, to a closed distal end; wherein the receptacle comprises an inner wall portion and an outer wall portion, the inner wall portion and the outer wall portion being connected to each other at the rim to form a closed cavity between the inner and outer wall portions; wherein at least a portion of the inner wall portion is configured for movement with respect to the outer wall portion to increase the internal volume of the cavity and thereby decrease the internal volume of the receptacle.
12. The heart support device of claim 11, wherein the outer wall portion is more rigid than the inner wall portion (4a).
13. The heart support device according to claim 11, further comprising a support structure to hold the outer wall portion in an open configuration.
14. The heart support device according to any of claim 13, wherein the support structure is disposed within the cavity defined between the inner and outer wall portions.
15. The heart support device according to claim 11, further comprising a first catheter or guide wire fixed to the outer wall portion at a first fixation point.
16. The heart support device according to claim 11, further comprising a second catheter fixed to the inner wall portion at a second fixation point.
17. The heart support device according to claim 16, wherein the second catheter is in fluid communication with the internal volume of the cavity.
18. The heart support device according to claim 11, wherein the first and second catheters are slidably mounted with respect to each other.
19. The heart support device according to claims 11, wherein the device further comprises actuation means configured to alternately increase and decrease the internal volume of the cavity, thereby alternately decreasing and increasing the internal volume of the receptacle.
20. The heart support device according to claim 19, wherein the actuation means comprises a delivery system for delivering fluid to and from the cavity between the inner and outer wall portions.
21. The heart support device according to claim 19, wherein the first catheter and the second catheter are configured to move with respect to each other in a reciprocating motion to alternately increase and decrease a distance between the first and second fixation points.
22. The heart support device according to claim 13, wherein the support structure comprises a shape-memory material.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0045] The present invention will now be described with reference to a number of exemplary embodiments shown in the following drawings:
[0046] FIG. 1 shows a heart assist device according to the present invention disposed within a heart chamber;
[0047] FIGS. 2A-2B show a cross-sectional view of the device of FIG. 1 during use, with the plane of the cross-section parallel to the long axis of the device;
[0048] FIG. 3 shows a cross-sectional view of the catheter shown in FIGS. 2A-2B, with the plane of the cross-section orthogonal to the long axis of the device;
[0049] FIGS. 4A-4B show a cross-sectional view of an alternative embodiment of the invention during use;
[0050] FIGS. 5A-5C show a cross-sectional view of a device according to an embodiment of the invention, before, during, and after deployment;
[0051] FIG. 6A-6C show a cross-sectional view of a device according to another embodiment of the invention, before, during, and after deployment.
DETAILED DESCRIPTION OF THE DRAWINGS
[0052] FIG. 1 shows an exemplary embodiment of a heart support device 2 for providing circulatory assistance. The heart support device 2 shown in FIG. 1 is configured to sit with a chamber of the heart (in the illustrated example, the left ventricle LV) and is configured to pump blood toward the aortic valve AV. The device 2 is advantageously mounted or connected to at least one catheter 6, 8 with which the device 2 is delivered and deployed. The device generally comprises a balloon having a distal portion, which is held in an open configuration (once deployed) and a proximal portion that is inverted with respect to the distal portion to form a concave, dual-walled receptacle 12 defining an internal volume Vr and a rim 14. To displace blood from within the receptacle 12, an interior volume of the cavity formed by the dual-walled construction is alternately increased and decreased. As the internal volume of the cavity is increased, the available volume within the concave dual-walled receptacle decreases, thus displacing blood through the open proximal end of the cavity, towards the aortic valve.
[0053] As used herein, the term “proximal” refers to the open end of the receptacle through which blood is displaced, and does not imply any particular orientation of the device with respect to the patient or the surgeon tasked with placement of the device. Moreover, although embodiments of the present invention are described herein with reference to a device adapted for placement in the left ventricle LV, the skilled person will appreciate that the present invention may also be implemented in devices adapted for placement in other heart chambers (e.g. the right ventricle), or for placement outside the heart (e.g. in the aorta). Embodiments of the present invention can be adapted and optimised for placement in different heart chambers and associated lumens by modifying the configuration and extension direction of any control and placement catheters, as will become apparent from the detailed description below.
[0054] Heart assist devices according to the present invention may provide a simple and effective way of providing an intra-lumen (intra-cardiac or intra-vascular) circulatory assist device, with a simple mechanical mode of deployment and actuation. These advantages, and further benefits provided by the present invention, will be apparent from the exemplary embodiments of the invention, which will now be described in more detail with reference to FIGS. 2-6.
[0055] FIGS. 2A and 2B show cross-sectional views of a heart assist device according to the present invention. FIG. 2A shows the device in a first configuration with the volume of the internal cavity between the two walls of the receptacle is at a minimum (e.g. when the available volume of the concave receptacle is at its largest and contains a maximum volume of blood). FIG. 2B shows the device in a second configuration in which the internal volume between the two walls of the chamber is at a maximum (e.g. when the available volume of the concave receptacle is at its smallest—possibly zero).
[0056] Turning first to FIG. 2A, the heart assist device 2 comprises a concave receptacle 12 defining an internal volume Vr. The receptacle 12 extends from an open proximal end, which is bounded by a proximal rim 14, to a closed distal end. As shown in FIG. 2A, the receptacle 12 can take the form of a cup. The internal volume Vr of the receptacle 12 is in fluid communication with a volume external to the receptacle. That is, the internal volume Vr of the receptacle can be filled with fluid from the environment in which it is placed, i.e. blood within a chamber of the heart.
[0057] The receptacle 12 comprises an inner wall portion 4a and an outer wall portion 4b, with the inner wall portion 4a and the outer wall portion 4b being joined to each other at the rim 14. The join between the inner wall portion 4a and the outer wall portion 4b is the point at which the inner wall portion 4a and the outer wall portion 4b meet to form the rim 14. A join between two distinct or separate components is not required, although it may be present in some embodiments. Between the outer wall portion 4a and the inner wall portion 4b, a closed cavity 3 is formed, which has an internal volume Vc.
[0058] The inner wall portion 4a and the outer wall portion 4b together form a balloon (described in more detail with reference to FIGS. 5A-5C), in which the inner wall portion 4a of the balloon has been inverted with respect to the outer wall portion 4b.
[0059] The outer wall portion 4b is supported in an open configuration to form the receptacle 12. The outer wall portion 4b can be supported in the open configuration in a number of ways. For example, the outer wall portion 4b can be formed of material that is biased into a self-supporting open configuration. The outer wall portion can also comprise an integrated support structure, e.g. a frame or a plurality of ribs forming part of or affixed to the outer wall portion 4b. Alternatively, a separate support structure can be provided, for example within the cavity between the inner and outer wall portions, as will be described in more detail below.
[0060] In the embodiment shown in FIGS. 2A and 2B, the outer wall portion 4b is self-supporting in the open configuration and is more rigid than the inner wall portion 4a. The outer wall portion 4b can be made more rigid than the inner wall portion 4a in a number of ways. It may be formed of the same material as the inner wall portion 4a, but have an increased thickness. It can be reinforced by dip-coating or by providing an additional support structure such as a mesh or scaffold attached to or integrated with the material of the outer wall portion 4b. The outer wall portion 4b may also be formed of a different material to the inner wall portion 4a, with a join formed therebetween. Preferably, the outer wall portion comprises nylon, polyurethane, polyether block amides (Pebax), polyethylene terephthalate (PET) or similar materials. Other suitable materials will also be apparent to the person skilled in the art.
[0061] Referring now to FIG. 2B, at least a portion of the inner wall portion 4b is configured for movement with respect to the outer wall portion 4b to increase the internal volume Vc of the cavity 3. As shown in FIG. 2B, as the internal volume Vc of the cavity 3 increases, the available volume Vr within the receptacle 12 decreases, and blood if forced in the direction of arrows B from the receptacle, through the proximal opening bounded by the rim 14. In the embodiment shown in FIG. 1, the device 2 is oriented with the proximal opening directed towards the aortic valve. Therefore, as the inner wall 4a expands into the internal volume Vr of the receptacle 12, blood B is displaced from the interior volume Vr of the receptacle 12 toward the aortic valve AV to assist the pumping action of the heart.
[0062] As shown in FIGS. 2A and 2B, because the inner wall portion 4a expands inwardly away from the outer wall portion 4b that forms the wall of the receptacle, an impulse is generated that directs the flow of blood towards the aorta. This arrangement is advantageous over many conventional displacement pumps, which rely on an expanding balloon to displace a volume of blood without controlling the direction of displacement.
[0063] The internal volume Vc of the cavity 3 can be varied in different ways and different actuation arrangements can be provided. For example, in the embodiment shown in FIGS. 2A and 2B, the internal volume Vc of the cavity 3 is increased by inflating the cavity Vc with a fluid (e.g. a liquid or gas).
[0064] In the embodiment shown in FIGS. 2A and 2B, a first catheter 6 extends through the inner wall portion 4a and attaches at a first fixation point P1 to the outer wall portion 4b. The first catheter 6 can be configured to maintain the position of the receptacle 12 within the heart, since the outer wall portion 4b does not deform after deployment within the heart chamber.
[0065] As illustrated, a second catheter 8 defining an internal lumen can be provided and configured to deliver an inflation fluid to the cavity 3. The inflation fluid can be gas or liquid, and can comprise one or more of e.g. helium, carbon dioxide, nitrogen, air and saline. As the inflation fluid fills the cavity 3, the inner wall portion 4a expands into the internal volume Vr of the receptacle 12. The second catheter 8 is fixed at a second fixation point P2 to the inner wall portion 4b. The first catheter 6 extends through the inner lumen of the second catheter 8.
[0066] The inner lumen of the second catheter 8 is in fluid communication with the internal volume Vc of the cavity 3 via one or more openings. One or more openings may be provided at an open distal end of the second catheter 8 and/or one or more openings may be provided along the outer walls of the tube that forms the catheter body (at a location that provides fluid communication with the internal volume Vc of the cavity 3). In addition to the first and second catheters 6, 8, a guide wire can be provided to aid in placement and deployment of the device 2. FIG. 3 shows an exemplary configuration comprising an outer catheter 8 defining an internal lumen for delivering inflation fluid to the cavity 3. The inner catheter 6 extends along the internal lumen, and defines its own internal lumen along which a guide wire 7 extends. The device can thus be advanced along guide wire 7 for positioning in the heart. It will be appreciated that the precise coaxial arrangement shown in FIG. 3 is not required in all embodiments of the invention. Moreover, if a guidewire is not required to place the device, the inner lumen of the first catheter 6 is not required and the inner catheter can be replaced with a wire.
[0067] In the embodiment shown in FIGS. 2A and 2B, when the device 2 is in the deployed configuration, the first fixation point P1 and the second fixation point P2 are fixed relative to each other. That is, the inner and outer catheters 6, 8 are not movable with respect to each other once the device has been deployed (although relative movement between the first and second catheters may be advantageous before deployment, as described in more detail with reference to FIGS. 5A-6C below). The position of the first and second fixation points P1 and P2 can advantageously be locked with respect to each other with a locking mechanism, and preferably a releasable locking mechanism. Such a locking mechanism (not shown) can be provided directly between the first and second fixation points P1, P2, within the receptacle 12, or it can be provided remotely by locking the first and second catheters 6, 8 relative to each other.
[0068] Although not shown in the drawings, a suitable locking mechanism can comprise a push-fit or snap-fit assembly within the cavity 3. For example, a locking mechanism can be formed integrally with the first and second fixation points. In such embodiments, the fixation point P2 can comprise a first locking component (e.g. a ring) about which a seal is formed between the proximal portion of the balloon and the first catheter. The first locking component can comprise a projection extending in a distal direction. The fixation point P1 can comprise a second locking component at which the second catheter is secured to the distal portion of the balloon. The second locking component can comprise a recess configured to receive the projection in the first locking component. The projection on the first locking component and the recess of the second locking component can comprise the male and female parts of a push-fit or snap-fit connector configured to secure the first and second catheters in the second position. An annular projection in the first component and an annular recess in the second component can provide snap-fit or push-fit of the first and second components regardless of the rotational orientation of the first and second fixation members. Alternative locking mechanisms such as bayonet and screw-threaded locking arrangements are also possible. A remote releasable locking mechanism for locking the first catheter with respect to the second catheter is described in more detail with reference to FIGS. 5A-5C.
[0069] With the first and second fixation points P1 and P2 fixed with respect to each other, in the embodiment shown in FIGS. 2A and 2B, the expansion of the internal volume Vc of the cavity is due to inflation of the cavity 3 with an inflating fluid. To this end, the inner wall portion 4a is configured to expand into the interior volume Vc of the cavity. The inner wall portion 4a can be elastic, or it can be inelastic but provided with enough slack (with the outer wall portion 4b is supported in the open position after deployment) to be inflated by the inflation fluid. The inner wall portion may comprise nylon, polyurethane, polyether block amides (Pebax), polyethylene terephthalate (PET) or similar materials. Other suitable materials will also be apparent to the person skilled in the art In preferred embodiments of the invention an elastic or at least semi-compliant membrane forms (at least part of) the inner wall portion 4a. Although an inelastic material can be used to provide suitable pumping, in at least some embodiments an elastic or semi-compliant material is preferred because a (relatively) smooth surface can be maintained within the receptacle, when the inner wall portion 4b is in the retracted position and the advanced position. The smooth surface that can be provided with an elastic membrane eliminates many of the creases that are formed in embodiments comprising a (slack) inelastic membrane, which may in turn reduce the formation of cavities in which thrombosis may occur, especially in high risk groups. . In any event, to ensure that the inflating fluid delivered to the cavity Vc does not enter the circulatory system of the user, the membrane that forms the inner wall portion 4a should be form a fluid-impermeable enclosure with the outer wall portion 4b to ensure that the cavity Vc is sealed from the internal volume of the heart.
[0070] Turning now to FIGS. 4A and 4B, in at least some embodiments of the invention, an alternative actuation system can be employed in which a distance Dx between the first and second fixation points P1 and P2 can be varied to alternately move the inner wall portion 4a towards and away from the outer wall portion 4b, thereby varying the internal volume Vc of the cavity 3. As described above, this in turn varies the available volume Vr of the receptacle 12 to pump blood through the open proximal end of the receptacle.
[0071] As shown in FIG. 4A, the heart support device 2 comprises a receptacle 12 that is generally similar to the receptacle 12 described with reference to FIG. 2A, and has an inner wall portion 4a and an outer wall portion 4b, joined to each other at a rim 14 to define a concave, dual-walled receptacle 12 having an internal volume Vr. A first catheter 6 is fixed at a first fixation point P1 to the outer wall portion 4b and a second catheter 8 is fixed at a second fixation point P2 to the inner wall portion 4a. Like the embodiment described with reference to FIG. 2A, the first catheter 6 can be accompanied by or replaced with a wire 7.
[0072] Unlike the embodiment shown in FIG. 2A and 2B, the first and second fixation points P1 and P2 are not fixed relative to each other when the device is in the deployed configuration, and as such the first catheter 6 is axially movable with respect to the second catheter 8.
[0073] As shown in FIG. 4B, as the first catheter 6 moves with respect to the second catheter 8, the distance between the first and second fixation points P1 and P2 increases. As the distance increases, the inner wall portion 4a is moved away from the outer wall portion 4b, thereby increasing the internal volume Vc of the cavity 3 between the inner and outer wall portions 4a, 4b. As described above, increasing the volume Vc of the internal cavity between the wall portions 4a, 4b decreases the available volume Vr of the receptacle 12, and expels blood contained within the receptacle 12 out of the open proximal end and towards the aortic valve. Because the inner wall portion 4a expands into the receptacle volume Vr away from the outer wall portion 4b, an impulse is created that expels blood through in the opening surrounded by rim 14 in a directional manner, e.g. towards the aortic valve in deployed arrangement shown in FIG. 1. This may improve the efficiency of the device and more closely approximate the natural function of the heart.
[0074] In at least some embodiments, the reciprocating catheter arrangement shown in FIGS. 4A and 4B can be combined with a catheter lumen configured to deliver inflating fluid to the internal volume Vc of the cavity 3. The inflation fluid can be configured to maintain a minimum pressure within the cavity 3 to expel blood from the receptacle 12 or it can be used to drive reciprocal movement of the catheter. Alternatively, the distance Dx between the first and second fixation points P1, P2 can be pushing and/or pulling one of the first and second catheters with respect to the other.
[0075] Instead of integrated support means to hold the outer wall 4b in an open configuration, the embodiment shown in FIG. 4A comprises a separate support structure 10 disposed within the inner cavity 3 between the inner and outer walls 4a, 4b. Although the support structure 10 is described with reference to the exemplary embodiment illustrated in FIG. 4A, the skilled person will appreciate that the support structure 10 can be employed in the embodiment shown in FIGS. 2A and 2B, in addition to or as an alternative to a more rigid outer wall portion 4b. The support structure 10 can comprise a cup, frame, support ribs or any other structure that holds the outer wall portion 4b in an open configuration when deployed in a heart chamber. The support structure 10 can also be omitted from the embodiment shown in FIGS. 4A and 4B, and replaced with a more rigid outer wall portion 4b or an integrated support structure (as described with reference to FIGS. 2A and 2B).
[0076] To ensure that the device 2 can be inserted into a suitable lumen in a minimally invasive manner (e.g. percutaneously), the outer wall portion 4b (and the optional additional support structure(s)) is preferably collapsible from its open configuration to a collapsed configuration to allow the device 2 to be advanced into the left ventricle LV through the aorta (alternative positions and placement routes are also possible). The outer wall portion 4b is thus preferably supported in the open or expanded configuration by a resiliently deformable material that can be deformed from an open configuration temporarily for insertion, but will revert to its original, open configuration when in place. Suitable resiliently deformable materials are known in the art and include elastically deformable polymers and e.g. shape memory materials such as shape memory alloys (e.g. nitinol) and shape memory polymers. Other collapsible support structures can also be provided to hold the outer wall portion 4b in the open configuration after deployment (e.g. inflatable ribs).
[0077] As discussed above, the device 2 is preferably formed or deployed by inverting a balloon 4 to form the inner and outer wall portions 4a, 4b. Inversion of the balloon 4 will now be described in more detail with reference to FIGS. 5A to 5C.
[0078] As shown in FIG. 5A, before deployment into the working configurations shown in FIGS. 2A-2B and 4A-4B, the device 2 comprises a balloon 4 defining a closed internal volume Vc. The balloon 4 extends from a proximal end to a distal end and comprises a proximal portion 4a and a distal portion 4b. A longitudinal axis A extends between the proximal end and the distal end. A first catheter 6 (or a guide wire) is affixed to a distal end of the balloon at a first fixation point P1. A second catheter 8 is fixed to the proximal end of the balloon 4 at a second fixation point P2 and comprises an internal lumen through which the first catheter 6 extends. In the embodiment shown in FIGS. 5A-5C, the distal portion 4b of the balloon 4 is supported in an open configuration by integrated support ribs 11. However, this arrangement can be exchanged for or supplemented by the reinforced or supported outer wall portions 4b described above with reference to FIGS. 2A-2B and 4A-4B.
[0079] Turning now to FIG. 5B, the second catheter 8 is slidably mounted with respect to the first catheter 6. As the second catheter 8 is slid distally with respect to the first catheter 6, the first fixation point P1 brought towards the second fixation point P2 and the distance Dx decreases. Since the distal portion 4b of the balloon is supported in an open configuration, as the first and second fixation points P1 and P2 approach each other, the proximal portion 4a of the balloon 4 begins to invert with respect to the distal portion 4b. As shown in FIG. 5C, with the first and second fixation points P1, P2 brought into close proximity, and with the distance Dx at its minimum value, the proximal portion 4a of the balloon 4 is fully inverted with respect to the distal portion 4b of the balloon 4 to form the dual-walled receptacle 12 described above with reference to FIGS. 2-4.
[0080] An example of a remote locking mechanism 16 that can lock the first and second fixation points P1, P2 in the position shown in the fully deployed position is also illustrated in FIGS. 5A-5C.
[0081] As shown in FIGS. 5A-5C, the first catheter 6 extends through the inner lumen of the second catheter 8 until it reaches a port 16 comprising an internal bore. At port 16, the second catheter 8 stops, and the first catheter extends through the port 16. The port 16 is switchable between a first configuration in which the first catheter 6 can move freely through the internal bore of the port, and a second configuration in which the catheter 6 is axially restrained from movement with respect to the port 16. As an example, the port 16 can thus comprise a selectively variable constriction that can be reduced from a first diameter at which the catheter 6 can slide freely through the constriction, to a smaller second diameter, that grips the catheter 6 and prevents axial movement thereof through the internal bore or the port 16. Alternative clamping arrangements can also be implemented, for example a screw clamp, or a parallelogram clamp.
[0082] In embodiments comprising an actuation system in which the distance Dx between the first and second fixation points P1 and P2 is varied (as described with reference to FIGS. 4A and 4B), movement of the first and second catheters 6, 8 relative to each other is permitted. However, advantageously, a blocking structure can be provided to prevent the distance Dx between P1 and P2 extending beyond predetermined set maximum distance (e.g. the distance Dx shown in FIG. 5A or 5B). Similar to the locking mechanism, the blocking arrangement can directly engage the first and or second fixation points or it can be provided remotely. By providing a predetermined maximum distance between the first and second fixation points P1 and P2, the stroke distance of the actuation system (and thus the stroke volume of the device) can be controlled.
[0083] In the embodiments described above, the device 2 is arranged such that the catheter(s) 6, 8 and optional guide wire(s) 7 extend in a proximal direction from the distal end of the device, through the internal volume Vr or the receptacle 12 and through the proximal opening (in the direction of the aorta, as shown in FIG. 1). In this configuration, the first catheter 6 passes through the inner wall portion 4a to the outer wall portion 4b and extends along the inner lumen of the outer catheter.
[0084] However, the skilled person will appreciate that the device 2 can also be configured with the catheter(s) 6, 8 (and optional guide wire(s) 7) extending in a distal direction, i.e. starting at the distal end of the device and extending away from the proximal opening. Such an embodiment is shown in FIGS. 6A-6C.
[0085] As shown in FIG. 6A, in some embodiments, the device can be arranged with the first catheter 6 attached to the distal wall portion 4b of the balloon 4 and defining the central lumen through which inflating fluid can be delivered to the interior volume Vc of the cavity 3. The second catheter 8 (which may be accompanied by or replaced with a guide wire 7) extends through the central lumen of the first catheter 6 and is affixed to the proximal portion 4a of the balloon 4 at the second fixation point P2. As shown in FIG. 6B and 6C, the balloon 4 can be inverted and controlled in a similar manner to the embodiment described above with reference to FIGS. 2-4, except that in the embodiment shown in FIGS. 6A-6C, the second catheter 8 must be moved distally relative to the second catheter in order to invert the balloon.
[0086] The present invention also comprises a method of deploying a heart assist device from an initial configuration to a working configuration, as illustrated in FIGS. 5A-5C and FIG. 6A-6C. Generally speaking, the method according to the invention comprises the steps of: providing a balloon 4 comprising a proximal portion 4a and a distal portion 4b; supporting the distal portion of the balloon 4 in an open configuration, and inverting the proximal portion of the balloon relative to the distal portion of the balloon. The inversion of the balloon 4 can be carried out using a first catheter 6 fixed to the distal wall portion 4b at a first fixation point P1 and a second catheter 8 fixed to the proximal wall portion 4a at a second fixation point P2, and by decreasing a distance Dx between the first and second fixation points P1 and P2 to invert the proximal wall 4a portion relative to the distal wall portion 4b to form a receptacle 12 having an internal volume Vr.
[0087] It will be appreciated that the method has been described with reference to a number of non-limiting exemplary embodiments and modifications can be made to the above described embodiments without departing from the scope of the invention. Moreover, features from the above-described embodiments can be combined with other embodiments described herein. For example, the support structures for the outer wall described herein are applicable to all embodiments. Moreover, the actuation arrangements, locking mechanisms and blocking structures, can be combined individually with other embodiments.
