Conjugated Prosthesis Treats Aortic Root Disease

An ascending aortic prosthesis (AAP) helps treat diseased, damaged, or malfunctioning native or prosthetic heart valves involved in an ascending aortic aneurysm.

The CryoLife (Kennesaw, GA, USA) On-X AAP combines the company’s On-X prosthetic heart valve and the Gelweave Valsalva vascular prosthesis, which is integrated into the cuff structure of the On-X prosthetic heart valve in order to create the AAP. The On-X prosthetic heart valve itself is a bileaflet mechanical heart valve with an orifice and two leaflets. In the closed position, each leaflet forms a nominal angle of 40º relative to the plane of the orifice. In the open position, each leaflet forms a nominal angle of 90º relative to the plane of the orifice. The orifice inflow area has a flared inlet designed to reduce flow turbulence.

The second component of the AAP, the Gelweave Valsalva vascular prosthesis is a woven polyester prosthesis designed to mimic the geometry of the sinus of Valsalva. The graft is impregnated with an absorbable modified mammalian gelatin in order to eliminate pre-clotting of the graft in surgery. After implantation, the gelatin is hydrolyzed within approximately 14 days and is then replaced by normal tissue.

The orifice itself is composed of a graphite substrate coated with On-X Carbon, a pure unalloyed form of pyrolytic carbon. The leaflets consist of On-X Carbon deposited on graphite substrates impregnated with 10% tungsten to provide radiopacity. The sewing cuff is made of polytetrafluoroethylene (PTFE) fabric mounted on the orifice using titanium retaining rings and 5-0 polyester suture material. This form of sewing cuff attachment to the orifice allows for rotation of the sewing cuff in situ during implantation. The AAP prosthesis is available in sizes 19, 21, 23, 25, and 27/29 mm.

An AAP is an enlargement of a weakened area in the ascending aorta. While other aneurysms of the aorta are associated with atherosclerosis, aneurysms of the ascending aorta are mostly associated with degenerative elastic fiber fragmentation and smooth muscle loss in the medial layer of the blood vessel wall. The aortic wall then loses its strength and elasticity, becoming aneurysmal, and may then dissect or rupture.

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