Expandable medical implant and percutaneous delivery

#The present invention generally relates to improved medical devices and their use. More particularly, the present invention relates to a medical implant having an annular ring and its percutaneous delivery means that is expandable for correction of certain disorders in the heart valves, blood vessel valves or other valvular body conduits in a patient.

#The human's circulatory system consists of a heart and many blood vessels. In its path through the heart, the blood encounters four valves. The valve on the right side that separates a right atrium from a right ventricle has three cusps and is called the tricuspid valve. It closes when the ventricle contracts during a phase known as systole and it opens when the ventricle relaxes, a phase known as diastole. The pulmonary valve separates the right ventricle from a pulmonary artery. The mitral valve, so named because of its resemblance to a bishop's mitre, is in the left ventricle and it separates the left atrium from the ventricle. The fourth valve is the aortic valve that separates the left ventricle from the aorta. In a venous circulatory system, a venous valve is to prevent the venous blood from leaking back into the upstream side so that the venous blood can return to the heart and consequently the lungs for blood oxygenating and waste removing purposes.

#In many patients who suffer from diseased or congenitally dysfunctional cardiovascular tissues, a medical implant may be used to correct the problems. A dysfunctional heart valve hinders the normal functioning of the atrioventricular orifices and operation of the heart. More specifically, defects such as narrowing of the valve stenosis or a defective closing of a valve, referred to as valvular insufficiency, result in accumulation of blood in a heart cavity or regurgitation of blood past the valve. If uncorrected, prolonged valvular insufficiency may cause eventually total valve replacement. On the other hand, certain diseases cause the dilation of the heat valve annulus. Dilation may also cause deformation of the valve geometry or shape displacing one or more of the valve cusps from the center of the valve. Dilation and/or deformation result in an ineffective closure of the valve during ventricular contraction, which results in regurgitation or leakage of blood during contraction.

#Additional objects and features of the present invention will become more apparent and the invention itself will be best understood from the following Detailed Description of Exemplary Embodiments, when read with reference to the accompanying drawings.

#FIG. 1 is a partial perspective view of an embodiment of the expandable annular ring of the present invention.

#FIG. 2A is a perspective view of a plurality of stenting elements made of shape-memory material for the annular ring at a pre-expansion state.

#With reference to the drawings FIGS. 1 to 8, what is shown is an embodiment of an expandable annular ring made of shape-memory materials having essentially uniform distensibility in the circumferential direction of the ring. The term “annular ring” is intended herein to mean any ring-shape structure suitable for placement at an annulus of a body. The term “annular ring with a uni-flow mechanism” is herein intended to mean any ring-shape structure incorporating a mechanism or structure for allowing fluid to flow through the annular ring in one direction, but not in an opposite direction. The uni-flow mechanism may comprise a plurality of valvular cusps configured for allowing fluid to flow through the annular ring in one direction.

#It is one aspect of the present invention to provide an expandable annular ring with a uni-flow mechanism for implantation in a valvular annulus of a patient comprising a plurality of stenting elements evenly spaced along the annular ring, wherein the stenting elements are made of a shape-memory material, the shape-memory material having a preshape and a shape-transition temperature, wherein the shape-memory material expands to its preshape so as to expand the annular ring when the shape-memory material is heated to above the shape-transition temperature.

#Jayaraman in U.S. Pat. No. 6,224,625, entire contents of which are incorporated herein by reference, discloses a low profile highly expandable stent including a Nitinol material. Jayaraman's stent is made of tubular pieces of material configured for the stent to expand both radially and longitudinally. Jayaraman further discloses a stent comprising generally cylindrical monolayer end pieces having a plurality of circumferentially spaced longitudinal slits showing a an intravascular/endoluminal stent that is significantly different from an annular ring in structure and in function of the present invention.