Each year, over 115,000 patients in the US need to have their diseased heart valves replaced with artificial devices. Although bioprosthetic valves are considered ideal, they wear out in about 15 years and are thus used primarily in the elderly who are not expected to outlive the valve. Younger patients receive mechanical valves that are more durable, but require chronic anticoagulation. This makes participation in most sports impossible and exposes the patient to increased risk for fatal bleeds and strokes. VXi is developing a two-part heart valve consisting of a permanent base and a plug-in exchangeable bioprosthetic tissue leaflet set. The VXi device is thus a lifetime bioprosthetic valve system that does not require anticoagulation. As the leaflet set begins to show signs of wear it can be exchanged rapidly, using a minimally invasive off-pump, beating heart procedure. Rapid, minimally invasive leaflet exchange significantly reduces the duration of redo surgery and eliminates the need for the technically demanding and potentially dangerous re-excision of the initial prosthetic valve. As the leaflet set is exchanged, the docking station remains in place, avoiding disruption of the aortic root and the nearby conduction system of the heart. VXi has successfully developed prototypes of its valves and demonstrated their exchangeability in a chronic animal model. In this Fast Track application, we propose to develop (i) the tools and techniques for minimally invasive, off-pump, beating-heart surgery for heart valve replacement, and (ii) a fully transapical implant of the initial docking station. The tools for valve implant and leaflet exchange evolve from our existing open surgery tool set. Access to the valve through the apex will be by way of a novel collapsible port technology pioneered by Dr. Gerard Guiraudon. Unlike conventional trocars, our introducer technology enables multiple tools to be inserted through a flexible cardiac port that enables a high degree of articulation, and rapid tool exchange. We propose to develop the transapical docking station, the port and the exchange tool technology and evaluate their function in a series of acute and chronic valve exchange experiments in the juvenile sheep model.
The development of transcatheter valves has been the only major innovation in the heart valve field in the past 30 years. These devices provide the reduction in invasiveness, but at the price of increased strokes and other procedural complications, and much reduced durability of the valve itself. Our technology thus offers the best combination of least invasive valve implant and leaflet exchange, with the same long-term durability of established surgical valves. Once developed and adopted by the marketplace, it will improve the quality of life for the majority of the 100,000 patients suffering from heart valve disease in the U.S., and reduce the expensive treatment of complications related to long-term use of anticoagulants.
