Implantable device utilizing arterial deformation

Abstract

The present invention relates to deforming a patient's artery. In a preferred embodiment, the deformation pressure is applied to the outer wall of the artery.

Claims

1. An implantable device, comprising: (a) a substantially inelastic shell comprising an outer surface and an inner surface, wherein the shell is curved such that the inner surface is substantially concave; (b) a flexible membrane sealingly coupled to the shell, wherein an inflatable space is defined between the flexible membrane and the inner surface, wherein the flexible membrane has a deflated configuration and an inflated configuration, wherein the inflated configuration is a smoothly curved ovate projection; (c) a port associated with the outer surface of the shell, wherein an interior portion of the port is in fluid communication with the inflatable space; and (d) a wrap coupled to the outer surface of the shell, the wrap configured to be removeably positionable around a portion of a patient's artery such that the flexible membrane is configured to be held against the artery, wherein the device has no other component or structure for holding the device against the artery, wherein the shell is configured to extend around only a portion of the circumference of the artery.

2. The implantable device of claim 1, wherein the flexible membrane is substantially inelastic.

3. The implantable device of claim 1, wherein the port is configured to be coupleable to a motive component.

4. The implantable device of claim 1, wherein a fluid is disposed within the inflatable space in the inflated configuration.

5. The implantable device of claim 4, wherein the fluid is a liquid.

6. The implantable device of claim 1, wherein the smooth curved ovate projection is configured to cause the artery to flex into a conic shape defined by a continuous line.

7. The implantable device of claim 1, wherein the smooth curved ovate projection is configured to cause the artery to flex substantially without stretching a wall of the artery.

8. An implantable device, comprising: (a) a substantially inelastic shell comprising an outer surface and an inner surface, wherein the shell is curved such that the inner surface is substantially concave; (b) a flexible membrane sealingly coupled to the shell, wherein an inflatable space is defined between the flexible membrane and the inner surface, wherein the flexible membrane has a deflated configuration and an inflated configuration, wherein the inflated configuration is a smoothly curved oval projection; (c) a port associated with the outer surface of the shell, wherein an interior portion of the port is in fluid communication with the inflatable space; and (d) a wrap coupled to the outer surface of the shell, the wrap configured to be removeably positionable around a portion of a patient's artery such that the flexible membrane is configured to be held against an outer side of the artery, wherein the device has no other component or structure for holding the device against the artery, wherein the smooth curved oval projection is configured to cause the outer side of the artery to progressively deform substantially without stretching a wall of the artery, wherein the shell is configured to extend around only a portion of the circumference of the artery.

9. The implantable device of claim 8, wherein the flexible membrane is substantially inelastic.

10. The implantable device of claim 8, wherein the port is configured to be coupleable to a motive component.

11. The implantable device of claim 8, wherein a fluid is disposed within the inflatable space in the inflated configuration.

12. The implantable device of claim 8, wherein the smooth curved ovate projection is further configured to cause the outer side of the artery to progressively deform into a conic shape defined by a continuous line.

13. An implantable device, comprising: (a) a shell comprising an outer surface and an inner surface, wherein the shell is curved such that the inner surface is substantially concave; (b) a substantially inelastic flexible membrane sealingly coupled to the shell, wherein an inflatable space is defined between the flexible membrane and the inner surface, wherein the flexible membrane has a deflated configuration and an inflated configuration, wherein the inflated configuration is a smoothly curved oval projection, and further wherein the flexible membrane is configured to be positionable against an outer side of a patient's artery; (c) a port associated with the outer surface of the shell, wherein an interior portion of the port is in fluid communication with the inflatable space; and (d) a wrap coupled to the outer surface of the shell, wherein the wrap is removeably positionable around a portion of the artery such that the wrap holds the device against an outer side of the artery, wherein the device has no other component or structure for holding the device against the artery, wherein the shell is configured to extend around only a portion of the circumference of the artery.

14. The implantable device of claim 13, wherein the port is configured to be coupleable to a motive component.

15. The implantable device of claim 13, wherein a fluid is disposed within the inflatable space in the inflated configuration.

16. The implantable device of claim 15, wherein the fluid is a liquid.

17. The implantable device of claim 13, wherein the smooth curved ovate projection is further configured to cause the outer side of the artery to progressively deform into the smoothly curved oval depression, wherein the smoothly curved oval depression is defined by a continuous line.

18. The implantable device of claim 13, wherein the smooth curved ovate projection is configured to cause the outer side of the artery to progressively deform into the smoothly curved oval depression without stretching a wall of the artery.

19. The implantable device of claim 13, wherein the smooth curved oval projection is configured to result in the outer side of the artery having a smoothly curved oval depression on an substantially unstretched wall of the artery.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Preferred embodiments of the invention will now be described, by way of examples only, with reference to the accompanying drawings in which

(2) FIG. 1 is a cross sectional ventral view of the aorta of a patient with a first embodiment of a device for assisting the functioning of a heart;

(3) FIG. 2 is a schematic lateral view of the device shown in FIG. 1;

(4) FIG. 3 is a ventral view of the aorta of a patient showing a series of planes through the aorta in which lines of flexure of the aortic wall will lie during application of a deforming force to the aorta;

(5) FIG. 4 is cross sectional view along line 4-4 through the aorta of FIG. 3 showing a sequence of shapes assumed by the aortic wall as it is deformed;

(6) FIG. 5 is a part longitudinal cross- sectional view through the aorta of FIG. 3 along line 5-5 of FIG. 6, showing a sequence of shapes assumed by the aortic wall as it is deformed;

(7) FIG. 6 is a lateral view from the right side of the aorta of FIG. 3, showing a sequence of lines of flexure as the aorta is deformed;

(8) FIG. 7 is a schematic side view of an ascending aorta showing a resection line;

(9) FIG. 8 is a schematic side view of the aorta shown in FIG. 7 after resection of a portion of the aorta;

(10) FIG. 9 is a schematic side view of another embodiment of a device for assisting the functioning of the heart with a withdrawn internal membrane;

(11) FIG. 10 is a schematic side view of the device shown in FIG. 9 with an expanded membrane;

(12) FIG. 11 is a schematic side view of the aorta shown in FIG. 8 after surgical attachment of the device shown in FIGS. 9 and 10 with the membrane shown in withdrawn and expanded positions;

(13) FIG. 12 is a schematic cross sectional end view of the aorta and device shown in FIG. 11;

(14) FIG. 13 is a schematic cross sectional view of an aorta of reduced size with a resected portion;

(15) FIG. 14 is a cross sectional end view of the aorta of FIGS. 13 and 15 after surgical attachment of a further embodiment of device for assisting in the functioning of the heart;

(16) FIG. 15 is a schematic front view of the resected aorta shown in FIG. 13;

(17) FIG. 16 is a schematic front view of the aorta and device shown in FIG. 15;

(18) FIG. 17 is a schematic side view of an ascending aorta showing an alternatively positioned resection line;

(19) FIG. 18 is a cross sectional ventral view of the aorta of a patient with a further embodiment of a device for assisting the functioning of a heart.

DETAILED DESCRIPTION

(20) FIG. 1 is a schematic side view of an ascending aorta 10 and a heart assist device 16 in accordance with an embodiment of the invention. The device 16 has a relatively inelastic, preferably plastic, shell 17 and a flexible membrane 18 sealingly attached to the periphery of the shell 17. The membrane 18 defines an inflatable space 19 between it and the interior of the shell 17. The shell 17 also has an inlet/outlet port 20 which is adapted for connection to a motive means that can periodically introduce, and withdraw, a fluid (eg. a gas such as helium or a liquid such as a saline solution or an oil) to and from the space 19 in counter-pulsation with the patient's heart rhythm. The membrane 18 has a shape which is, when deflated, smoothly curved and facing directly inwardly towards the lumen of the ascending aorta 10.

(21) A relatively inelastic wrap 21 is used to hold the device 16 in the position shown on the radially outer side of the ascending aorta 10.

(22) The solid line 18 illustrates the position of the membrane 18 relative to the shell 17 when fluid has been withdrawn from the space 19 and the membrane 18 has been retracted. In this position the radially outer external side wall 10e of the aorta 10 is in its normal or deflated position allowing maximum blood flow there through.

(23) The phantom line 18 illustrates the position of the membrane 18 relative to the shell 17 after fluid has been introduced into the space 19 and the membrane 18 has been expanded. When the membrane 18 is expanded in this way, the aorta external wall 10e is compressed and inwardly deformed until it is close to, but not abutting, the opposite interior wall of the aorta 10r.

(24) The membrane 18 is sized and positioned to compress only a portion of the circumference of the radially outer side of the ascending aorta 10. More particularly, the membrane 18 compresses only about 140 degrees of the circumference of the aorta 10.

(25) FIGS. 3 to 6 show, in various orientations and views, the shape the external wall 10e of the ascending aorta 10 assumes from initial deformation (line A) through to maximum deformation (line E). The lines A to E show the exterior of the aorta 10 flexing along a continuous line, that preferably has the shape of a conic section, which increases in length as the counter pulsation pressure applied to the artery increases. An advantage of flexing the aorta in this manner is that it is caused to compress substantially without stretching, which reduces the likelihood of damage. Also the line of flexure is constantly moving so that one line of the aorta 10 is not being constantly exposed to flexural movement. Put another way, the exterior of the aorta is deformed to induce a smoothly curved ovate depression as it moves towards a position of maximum deformation (line E) of the aorta 10. In an alternative embodiment, a smoothly curved circular depression can be formed in the aorta.

(26) The lines A to E also show how the artery is progressively deformed along a line which lies in a plane running through the artery 10, that plane moving radially inwardly through the artery as the deformation increases.

(27) The deformation described above can be caused to occur in many other different ways. For example, in another embodiment, deformation can be caused by a patch device inserted into the radially outer arc of the ascending aorta. In such an embodiment, the device includes a means for applying pressure to the wall or patch which, when the wall or patch is fully invaginated, forms a shape which is a mirror image of the section of the wall or patch which as been invaginated before it was so invaginated.

(28) Another embodiment of a device for assisting the functioning of a heart according to the present invention will now be described in relation to FIGS. 7 to 12. Like reference numerals will be used to indicate like features used in describing to the preceding embodiment.

(29) FIG. 7 is a schematic side view of a portion of ascending aorta 10. Line 12 is a resection line passing through the diameter of the midpoint cross section of the aorta 10 (see also FIG. 12).

(30) FIG. 8 is a schematic view of the resected aorta 10r after cutting the aorta 10 along the resection line 12 and removal of a resected portion 14.

(31) FIG. 9 is a schematic side view of a heart assist device 16 in accordance with another embodiment of the invention. The device 16 has a relatively inelastic, preferably plastic, shell 17 and a flexible membrane 18 sealingly attached to the periphery of the shell 17. The membrane 18 defines an inflatable space 19 between it and the interior of the shell 17. The shell 17 also has an inlet/outlet port 20 which is adapted for connection to a motive means that can periodically introduce, and withdraw, a fluid (eg. a gas such as helium or a liquid such as a saline solution or an oil) to and from the space 19 in counter-pulsation with the patient's heart rhythm.

(32) FIG. 9 illustrates the position of the membrane 18 relative to the shell 17 when fluid has been withdrawn from the space 19 and the membrane 18 has been retracted (18r in FIGS. 11 and 12). FIG. 10 illustrates the position of the membrane 18 relative to the shell 17 after fluid has been introduced into the space 19 and the membrane 18 has been expanded (18e in FIGS. 11 and 12). When the membrane 18 is expanded it is close to, but not abutting, the opposite interior wall of the aorta 10r.

(33) The shell 17 has a peripheral edge of common shape to the opening formed in the aorta 10r after removal of the resected portion 14. This permits the device 16 to be attached to the resected aorta 10r by stitching between the periphery of the shell 17 and the periphery of the opening in the resected aorta 10r, as indicated by stitches 22 in FIG. 11.

(34) The motive means (not shown) include a fluid reservoir and a pump means adapted to pump the fluid from, the fluid reservoir to the port 20, and thus the space 19 between the interior of the shell 17 and the flexible membrane 18, and then withdrawn same, to expand (18e) and retract (18r) the membrane 18 as indicated in FIGS. 5 and 6. Suitable implantable fluid reservoirs and pump means are disclosed in the applicant's international PCT patent application Nos. PCT/AUOO/00654 and PCT/AUO2/00974, which are hereby incorporated by cross reference.

(35) More particularly, in use, the motive means is periodically actuated to introduce fluid into the space 19 in synchrony with the diastole period to reduce the interior volume of the aorta 10r and thereby provide additional pumping of the blood in the aorta 10r to assist the functioning of the heart. This introduction of fluid is alternated with periodic withdrawal of the fluid from the space 19 to allow the aorta 10r to return to its normal interior volume. As described above, the introduction of fluid expands the membrane 18 to be close to, but not abutting, the opposite interior wall of the aorta 10r. This maximises pumping volume without risk of the membrane 18 contacting and damaging the aorta 10r.

(36) It will be appreciated that the heart assist device 16 includes a component, namely the membrane 18, which is blood contacting. However, the previously described disadvantages of blood contacting are minimised by the present invention as when the fluid is withdrawn from the space 19 the membrane 18 is drawn into a shape substantially replicating the original (now resected) aorta wall. As a result, no eddies or pockets are introduced into the blood flow path that may disrupt blood flow when the device 16 is not activated thereby substantially reducing clot risk.

(37) Also, if the heart recovers the device 16 can be deactivated with the membrane 18 in the retracted position (see FIGS. 9 and 18r in FIGS. 11 and 12) allowing natural blood flow there through. In this connection, it should also be noted that heart assist devices have been proposed that function in parallel to the aorta and which receive the full diverted flow of blood originally intended for to the aorta. These devices can not be deactivated unlike the device according to the present invention.

(38) Further, by installing the device 16 in a position vacated by the resected portion 14 of the aorta 10 it achieves a relatively high pumping volume for a relatively low device volume.

(39) The flexible membrane 18 is preferably manufactured from a polyurethane or a polyurethane-polysiloxane block co-polymer material or other similar material, which encourages ingrowth of the passing blood cells and can eventually create a new natural cell lining.

(40) The device according to the present invention is also particularly advantageous for use in patients whose aortas have become diseased as the device can be implanted in place of the resected damaged section.

(41) A further embodiment of the device for assisting the functioning of a heart according to the present invention will now be described in relation to FIGS. 13 to 16. Like reference numerals will be used to indicate like features used in describing to the preceding embodiment. This embodiment is particularly suitable for use in patients having a naturally small aorta or an aorta that has shrunk through heart disease or the like.

(42) FIG. 13 is a schematic cross sectional end view of a reduced diameter resected aorta 10r showing resection line 12 and resected portion 14. The periphery of the opening formed by removing the resected portion 14 is denoted 24 in FIG. 15. FIG. 14 shows the resected aorta 10r after its included angle {acute over ()} has been increased to {acute over ()}+ so as to open or stretch out the opening 24 in the aorta 10r. Such stretching allows the attachment of a heart assist device 16 of a similar size to that used in a healthy aorta. In this way, the effective cross section of the aorta available for pumping by the membrane 18 can be increased. For example, from about 707 mm.sup.2 at an original diameter of 30 mm to about 1257 mm.sup.2 at a stretched diameter of 40 mm. This results in a corresponding increase in the pumping volume of the aorta 10r.

(43) FIG. 17 is a schematic side view of an ascending aorta 10 showing an alternatively positioned resection line 12. In this form, the resection line 12 is angled towards the top of the aorta 10 to resect the upper, radially outer arc of the aorta 10.

(44) A further embodiment of a device for assisting the functioning of a heart according to the present invention will now be described in relation to FIG. 18. Like reference numerals will be used to indicate like features used in describing to the preceding embodiments.

(45) In FIG. 18 the heart assist device is a patch device 16 attachable to the ends of the aorta 10, at stitches 22, formed by removing a length of the aorta. The patch device 10 is in the general shape of a truncated toroid with an externally facing hump that forms the inflatable space 19. The membrane 18 is attached to the patch device 16 about the periphery of the hump. The hump is disposed external to a line on the radially outer side, or passing through, the diameter of the mid point cross section of the aorta 10.

(46) The flexible membrane 18 substantially replicates the shape of the interior of the hump when the fluid is withdrawn from the space 19. The membrane 18, when the fluid is introduced into the space 19, is expanded close to, but not abutting, the adjacent interior wall of the aorta, as is shown in phantom line.

(47) Whilst the above embodiments have been described in relation to compressing the radially outer wall of the aorta, it would be appreciated by a person skilled in the art that other portions of the aorta can be deformed or other arteries can be deformed to assist in heart functions.

(48) The heart assist devices described above are suitable for short and/or long term treatment for heart failure and/or myocardial ischemia.

(49) It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.