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 bioprostheses carries significant operative mortality, bioprostheses cannot be implanted in patients younger than 65. These patients receive mechanical valves and anticoagulation therapy, and hence suffer the risks of thromboembolism. We have conceived of an alternative approach to dealing with the durability problems of bioprosthetic valves, and the associated risk of reoperation. The VALVEXCHANGE procedure enables tissue-based heart valves to 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. In this Phase I proposal, we aim to (i) develop and fabricate a functioning prototype of the exchangeable valve, (ii) confirm its integrity in a hydrodynamic durability tester, and (iii) evaluate the efficacy of the rapid exchange process in a sheep model. Prototypes will be designed using ProEngineer by way of a subcontract to the Cleveland Advanced Manufacturing Center, and evaluated in a hydrodynamic tester at The Cleveland Clinic Foundation. Final designs will be implanted into a sheep model at the University of Wisconsin. In the animal study, we will be able to determine if the snap-out-snap-in approach is faster and more convenient than conventional suturing. Through these proposed studies, we will demonstrate that (i) we can fabricate the exchangeable heart valve to functional design specifications, and (ii) the two-piece valve concept has specific advantages in the surgical arena. Once we have achieved these milestones, we will apply for Phase II funding.
