News Column

Patent Issued for Heart Assist Device Utilising Aortic Deformation

July 28, 2014



By a News Reporter-Staff News Editor at Cardiovascular Week -- Sunshine Heart Company Pty. Ltd. (Clontarf, NSW, AU) has been issued patent number 8777833, according to news reporting originating out of Alexandria, Virginia, by NewsRx editors (see also Sunshine Heart Company Pty. Ltd.).

The patent's inventors are Peters, William Suttle (Auckland, NZ); Miller, Scott Hugh (Manly, AU); Watterson, Peter Andrew (West Ryde, AU).

This patent was filed on March 7, 2008 and was published online on July 15, 2014.

From the background information supplied by the inventors, news correspondents obtained the following quote: "The concept of providing counter-pulsation support for the failing heart has been known since the pioneering work of Kantrowitz. Counter-pulsation causes displacement of a volume of a patient's blood in the patient's aorta while the patient's heart is dilating in diastole and after the aortic valve has closed. This assists to move blood around the patient's peripheral vasculature as well as into the coronary arteries. The timed volume displacement in the aorta on the blood within the aorta just in advance of systolic ejection of blood from the heart reduces the afterload on the heart, by causing a transient low pressure above the aortic valve.

"It is known from the use of counter-pulsation in Intra-Aortic Blood Pumps (IABPs) that counter-pulsation can provide short term support for the failing heart. These devices require a balloon to be inserted percutaneously into the descending aorta. The balloon is inflated and deflated in counter-pulsation with the heart by the transmission of a gas, usually helium, between the balloon and a bedside console. These devices suffer from the problem that there is a high risk of thrombo-embolism if the balloon remains in the vasculature for a prolonged period, which can lead to ischemic leg complications.

"There have been a number of attempts to provide counter-pulsation support for the failing heart by applying counter-pulsation pressure to the outside of the aorta. These proposals are contained in the following patent specifications:

"TABLE-US-00001 PCT 99/04833 USA 4,014,318 USA 4,583,523 USA 4,979,936 USA 6,030,336 USA 6,045,496

"A similar arrangement is described by Furman, New York Journal of Medicine, Aug. 1, 1970, pp 1964-1969. In all of these arrangements means are provided to surround, or at least substantially surround, the aorta and to apply a squeezing pressure substantially uniformly around the circumference of the aorta. The present inventors have found that there are substantial advantages if the counter-pulsation pressure is applied to only a part of the circumference of the aorta.

"It is also known to resect a part of the aorta for the purpose of inserting a patch or other graft into the aorta and to cause such patch or graft to counterpulsate. Such a system is described in the following patent specifications:

"TABLE-US-00002 PCT 01/13974 USA 4,630,597

"The device described in these specifications is for insertion into the descending aorta which is straight. There is no suggestion of how to deal with the more complex issues that arise in placing the device into the ascending aorta which is curved along its length."

Supplementing the background information on this patent, NewsRx reporters also obtained the inventors' summary information for this patent: "In one aspect, the present invention provides a device for assisting the functioning of the heart of a patient, the device including:

"an aortic compression means adapted, when actuated, to compress an aorta; and

"motive means to periodically actuate, and de-actuate, the aortic compression means in counter-pulsation with the patient's heart rhythm,

"wherein the aortic compression means is adapted to compress only a portion of the circumference of the aorta.

"Preferably, the aortic compression means is adapted to compress less than half of the circumference of the aorta.

"In one form, the aortic compression means is a mechanical device driven, upon actuation, into compressive contact with the exterior of the aorta. In another form, the aortic compression means includes a flexible membrane, which may be elastic or inelastic, driven, upon inflation, into compressive contact with the exterior of the aorta.

"The aortic compression means is preferably adapted to compress only a portion of the circumference of the ascending aorta, most preferably only the radially outer side of the ascending aorta.

"In a second aspect, the present invention provides, in a heart assist device of the type which induces counter-pulsation of an artery in the vasculature of a patient, the improvement comprising the application of a counter-pulsation pressure to the exterior of the artery such that the artery is caused to flex along a continuous line which increases in length as the counterpulsation pressure applied to the artery increases.

"The line preferably has the shape of a conic section.

"In a third aspect, the present invention provides, in a heart assist device of the type which induces counterpulsation of an artery in the vasculature of a patient, the improvement comprising the application of a counterpulsation pressure to the exterior of the artery such that the artery is caused to compress substantially without stretching or bunching.

"In a fourth aspect, the present invention provides, in a heart assist device which includes aorta deformation means to apply a counter-pulsation pressure to the ascending aorta of a patient, characterised in that the aorta deformation means applies a deforming force to the outside of the radially outer side of the curvature in the ascending aorta and that the aorta deformation means induces in the aorta a smoothly curved ovate depression as it moves to a position of maximum deformation of the aorta.

"In a fifth aspect, the present invention provides, in a heart assist device which includes aorta deformation means to apply a counter-pulsation pressure to the descending aorta of a patient, characterised in that the aorta deformation means applies a deforming force to the outside of the descending aorta and that the aorta deformation means induces in the aorta a smoothly curved circular depression as it moves to a position of maximum deformation of the aorta.

"In a sixth aspect, the present invention provides, in a heart assist device including artery deformation means adapted to periodically apply a deforming force to a curved artery in a direction substantially normal to a tangent to the radially outer surface of the longitudinal curve in the artery, the deforming force being such that the artery is progressively deformed along a line which lies in a plane running through the artery, the plane moving radially inwardly through the artery as the deformation increases.

"In a seventh aspect, the present invention provides, in a counter-pulsation type heart assist device adapted for insertion into the wall of the ascending aorta of a patient, the device including an inflatable balloon extending around less than one half of the circumference of the aorta and means to inflate the balloon in counter-pulsation with the heart of a patient into which the device has been inserted, the balloon having a substantially inelastic outer layer and an inner layer with a shape which is, when the balloon is deflated, smoothly curved and facing directly inwardly into the lumen of the ascending aorta of the patient into which the device has been inserted. Alternatively the device may be applied to the outside of the wall of the aorta.

"In an eighth aspect, the present invention provides, in a heart assist device adapted to apply a counter-pulsation force to a patch inserted into at least the radially outer arc of the ascending aorta the force being applied to the radially outer arc of the aorta to cause the wall or the patch to invaginate, the device being characterised in that it includes deformation means for the application of the pressure to the wall or patch which deformation means has, when the wall or patch is fully invaginated, a shape which is substantially a mirror image of the section of the wall or patch which has been invaginated before it was so invaginated. Alternatively the device may be applied to the outside of the wall of the aorta.

"The above embodiment is designed to apply a compressive force to the artery so as to cause the blood therein to be displaced while causing the minimum trauma to the vessel. In preferred embodiments of the invention the compression of the ascending aorta is induced in a way which reduces the enclosed volume of the aorta while not unduly stretching or bunching the wall of the aorta.

"The deformation of the artery may be induced by a balloon or by a rigid object. In either case the object inducing the deformation shall be so shaped that the desired form of deformation of the artery is achieved. In the case of a balloon, the balloon should be so shaped that as it is inflated it will take on a shape similar to that which is desired to be achieved in the artery. It must also be so placed on the artery that the desired smoothly flexing and smoothly shaped deformation is achieved. In the case of a rigid object the object should initially be of an appropriate shape to induce the desired deformation of the artery as it is advanced towards the artery either along a linear path or an arcuate one. Preferably, the deforming object will be moved into the artery in a direction which is radial of the artery and either at right angles to its axis, if it is straight, or at right angles to a tangent to the radially outer side of the artery, if it is curved.

"Preferably, the deformation of the vessel does not extend around more than 180 degrees of the circumference of the vessel, more preferably no more than 160 degrees and even more preferably not more than 140 degrees and most preferably between 100 and 140 degrees. The cuff or balloon may extend further around the aorta than the preferred amount, however, the active deformation of the aorta preferably only extends around an arc of the aorta within the above limits. The desire of this design preference is to avoid the inside surface of the deformed vessel touching the inside surface of the vessel diametrically opposite the deformation.

"In preferred embodiments the deformational force will be applied directly to the arterial wall. However, if desired a layer of any suitable material may be placed between the deformational member and the wall. In an alternative embodiment of the invention a section of the arterial wall may be resected and a patch applied which substantially replicates the shape of the native artery and the deformational force applied to the outside surface of that patch. In this embodiment of the invention the patch is applied to the radially outer arc of the ascending aorta and preferably has a shape similar to the section of the ascending aorta which has been removed.

"The heart assist device of the present invention allows, at least in preferred embodiments, partial unloading of the heart and augmenting of the cardiac output of the heart.

"After use, if the heart has recovered, the device can be left in situ, in an inactive state, until needed again. The device can also be used to administer on-demand, spaced-apart sessions of counterpulsation for treatment or relief from chronic myocardial ischemia and/or heart failure.

"In a preferred form of the invention, the device is adapted for attachment to the ascending aorta. An upper mid-line sternotomy provides surgical access to the ascending aorta. Alternatively, a thoracotomy may be used to place the device on the descending aorta.

"The motive means referred to above can be any means that is capable of cyclically introducing fluid, and withdrawing fluid, from an inflatable bladder, balloon or cuff. The motive means can include or be associated with means for detecting speed and completeness of the filling and emptying, and for monitoring the delivered fluid pressure. The motive means can also act to record the ECG, having electrodes positioned on the housing or as separate wires attached to body tissues.

"In a further aspect, the present invention provides a method for improving cardiac performance in a subject, the method including the steps of:

"implanting a device in accordance with any one of the preceding aspects of the invention fully within the thoracic cavity of a subject;

"actuating the motive means to periodically introduce the fluid into the space in synchrony with the diastolic period to reduce the interior volume of the aorta; and

"alternating the period of actuation with periods of deactivation of the motive means to periodically withdraw the fluid from the space in synchrony with the commencement of the systolic period, thereby allowing the portion of the aorta adjacent the device to return to normal interior volume.

"The method may include the step of resecting a portion of the ascending aorta in the shape of a toroidal truncate and sealingly attaching the periphery of the device to the periphery of the opening aorta.

"In another aspect, the present invention provides a device for assisting the functioning of the heart of a patient, the device including:

"a patch device sealingly attachable to the ascending aorta;

"a flexible membrane sealingly attached to at least part of the interior of the patch device and defining an inflatable space adjacent the interior of the patch device; and

"motive means to periodically introduce into, and withdraw from, the space a fluid, in counter-pulsation with the patient's heart rhythm.

"The patch device is preferably attachable to the radially outer side of the ascending aorta. In one form, the patch device is attachable to the periphery of an opening in the ascending aorta formed by resecting a portion of the aorta. The membrane has a shape substantially replicating that of the interior surface of the resected portion of the aorta. The flexible membrane preferably also substantially replicates the shape of the interior of the patch device when the fluid is withdrawn from the space. It is believed that this design feature will reduce the incidence of thrombo-embolism by presenting, when deflated, a blood flow path without regions that would cause sluggish blood flow. The patch device is preferably in the shape of a truncated portion of a torus. The aorta is preferably resected along a line on the radially outer side, or passing through, the diameter of the mid point cross section of the aorta. The membrane, when the fluid is introduced into the space, is preferably expanded towards, but not abutting, the adjacent interior wall of the aorta.

"In another form, the patch device is attachable to the ends of the aorta formed by removing a length of the aorta. The patch device preferably includes a truncated substantially toroidal portion with an externally facing hump that forms the inflatable space. The membrane is preferably attached to the patch device about the periphery of the hump. The surface of the membrane remote the space preferably has a shape, when the fluid is withdrawn from the space, substantially replicating that of the interior surface of the removed portion of the aorta. The flexible membrane preferably also substantially replicates the shape of the interior of the hump when the fluid is withdrawn from the space. The hump is preferably disposed external to a line on the radially outer side, or passing through, the diameter of the mid point cross section of the aorta. The membrane, when the fluid is introduced into the space, is preferably expanded close to, but not abutting, the adjacent interior wall of the aorta."

For the URL and additional information on this patent, see: Peters, William Suttle; Miller, Scott Hugh; Watterson, Peter Andrew. Heart Assist Device Utilising Aortic Deformation. U.S. Patent Number 8777833, filed March 7, 2008, and published online on July 15, 2014. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=8777833.PN.&OS=PN/8777833RS=PN/8777833

Keywords for this news article include: Cardiology, Sunshine Heart Company Pty. Ltd.

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Source: Cardiovascular Week


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