Sequentially deployed transcatheter mitral valve prosthesis

#1. Field of the Invention

#The present invention generally relates to medical devices and methods, and more particularly relates to the treatment of valve insufficiency, such as mitral insufficiency, also referred to as mitral regurgitation. The use of prosthetic valves delivered by traditional surgical implantation methods, or by a less invasive percutaneous catheter or by minimally invasive transapical methods are one possible treatment for valvar insufficiency (also referred to as regurgitation).

#The heart of vertebrate animals is divided into four chambers, and is equipped with four valves (the mitral, aortic, pulmonary and tricuspid valves) that ensure that blood pumped by the heart flows in a forward direction through the cardiovascular system. The mitral valve of a healthy heart prevents the backflow of blood from the left ventricle into the left atrium of the heart, and comprises two flexible leaflets (anterior and posterior) that close when the left ventricle contracts. The leaflets are attached to a fibrous annulus, and their free edges are tethered by subvalvular chordae tendineae to papillary muscles in the left ventricle to prevent them from prolapsing into the left atrium during the contraction of the left ventricle.

#The novel features of the invention are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings of which:

#FIG. 1 is a schematic illustration of the left ventricle of a heart showing blood flow during systole with arrows.

#FIG. 2 is a schematic illustration of the left ventricle of a heart having prolapsed leaflets in the mitral valve.

#Specific embodiments of the disclosed device, delivery system, and method will now be described with reference to the drawings. Nothing in this detailed description is intended to imply that any particular component, feature, or step is essential to the invention.

#Cardiac Anatomy. The left ventricle LV of a normal heart H in systole is illustrated in FIG. 1. The left ventricle LV is contracting and blood flows outwardly through the aortic valve AV, a tricuspid valve in the direction of the arrows. Back flow of blood or “regurgitation” through the mitral valve MV is prevented since the mitral valve is configured as a “check valve” which prevents back flow when pressure in the left ventricle is higher than that in the left atrium LA. The mitral valve MV comprises a pair of leaflets having free edges FE which meet evenly to close, as illustrated in FIG. 1. The opposite ends of the leaflets LF are attached to the surrounding heart structure along an annular region referred to as the annulus AN. The free edges FE of the leaflets LF are secured to the lower portions of the left ventricle LV through chordae tendineae CT (also referred to herein as the chordae) which include a plurality of branching tendons secured over the lower surfaces of each of the valve leaflets LF. The chordae CT in turn, are attached to the papillary muscles PM which extend upwardly from the lower portions of the left ventricle and interventricular septum IVS.

#Referring now to FIGS. 2-4, a number of structural defects in the heart can cause mitral valve regurgitation. Ruptured chordae RCT, as shown in FIG. 2, can cause a valve leaflet LF2 to prolapse since inadequate tension is transmitted to the leaflet via the chordae. While the other leaflet LF1 maintains a normal profile, the two valve leaflets do not properly meet and leakage from the left ventricle LV into the left atrium LA will occur, as shown by the arrow.