Postcardiotomy shock (failure to wean from bypass) remains a highly morbid event. Roughly 60% of patients will wean from a short-term (mean 5 days) left ventricular assist device (LVAD), but only half of these patients will survive to discharge. Likewise, Cardiogenic Shock (CS) is a serious clinical condition responsible for a majority of early deaths from acute myocardial infarction (AMI) with 50% 30-day and 80-90% overall mortality. All current LVADs used to treat post-cardiotomy shock use a blood return graft (or cannula) to the aorta and a large cannula (>16 mm outer diameter) through the cardiac apex. Our goal is to develop a Plug and Play (P&P) TransApical to Aorta VAD pump that is simple and easily inserted within a few minutes with flows up to 10 L/min against 100 mmHg afterload for up to 3 months reliable performance. By immediately reducing left ventricle (LV) wall stress and distension and by preventing LV enlargement our P&P TransApical to Aorta VAD pump will serve as either a bridge to transplant or recovery from cardiogenic shock.
Our specific aims are to: 1) Fabricate a prototype design that includes efficient, thrombus free heparin saline purged needle roller bearings, which decreases bearing friction, increases durability, improves pump efficiency, and prevents thrombosis generation. Other modifications include blood path enlargement and shortening to decrease resistance and increase pulsatility, and the addition of a formed metal disk to facilitate surgical attachment. 2) Perform bench testing for performance and durability at different RPM's. We anticipate a pump flow of 10 L/min @ 17,500 RPM against a 100 mmHg afterload with a pump controller accuracy of 5%. A mock loop durability test for 3 months will assess failure or wear. 3) Perform large animal studies of our new prototype P&P TransApical to Aorta VAD: One-day studies in healthy sheep (n=10) will determine the amount of LV assistance achievable by a P&P TransApical to Aorta VAD and will demonstrate the interaction of the pump with intraventricular structures such as the anterior leaflet of the mitral valve and sub valvular structures. This performance testing will direct any further prototype modifications. Utilizing the final P&P TransApical to Aorta VAD prototype design coupled with the newly designed portable pump control system, we will then test the feasibility of the system design as a chronic ambulatory device in healthy sheep (n=3) for 5 days. Successful completion of Phase I will allow further refinement for long-term animal testing in Phase II, leading to pre-clinical testing in a large animal injury model. Catastrophic heart failure is a leading cause of death in patients following heart surgery and in some patients following a heart attack. We have designed, developed and will build a working """"""""plug and play"""""""" pump (the size of a ballpoint pen) that is inserted directly into the failing heart within minutes to provide total support of the circulation. This unique design will allow immediate heart support for up to 3 months to allow the heart to recover or serve as a bridge to transplantation. Our simple, easily inserted pump will revolutionize the field of mechanical heart assist. ? ? ?
