Biocompatiibility of Rapidly Exchangeable Heart Valve

DESCRIPTION (provided by applicant): Each year, 70,000 patients in the United States need to have their diseased heart valves replaced with artificial devices. Although bioprosthetic valves have few complications and are considered ideal for most patients, they wear out in 12-15 years. Because surgery to replace a worn out valve carries significant operative mortality, bioprostheses cannot be implanted into patients younger than 65. We have addressed the durability problems of bioprosthetic valves, and the associated risk of reoperation, by developing a rapidly exchangeable bioprosthetic valve that can be replaced without conventional open-heart surgery. The novelty of this approach is a two-component valve, consisting of a permanent "docking station" that remains affixed to the patient's aorta, and a collapsible frame that supports the leaflets and plugs into the docking station. Once the original leaflets wear out, they can be quickly exchanged with a new set using minimally invasive surgery. The specific aims of this Phase I research proposal focus on identifying and testing non-adhesive coatings to prevent tissue overgrowth in the area where the two components mate together and disengage. We aim to (J) identify a number of coatings that can be applied to metals and plastics to render them non-thrombogenic and non-adhesive to cellular overgrowth, (ii) develop, manufacture and coat test fixtures that can be implanted into a sheep model to investigate tissue overgrowth, and (iii) explant the test fixtures after 3 months and measure the thickness of pannus and its impact on the forces required to disengage and re-engage the mating components. This study builds upon our previous SBIR project in which functional prototypes of the two-piece valve were tested in vitro and in vivo. We will continue to work with the Cleveland Advanced Manufacturing Center and the University of Wisconsin. Through these proposed studies, we will demonstrate that anti-adhesion coatings can be applied to our two-piece valve to prevent pannus overgrowth in the areas where the two components connect. Once we have achieved these objectives, we will apply for Phase II funding.