DOES A ROTARY PUMP PROVIDE FULL CARDIAC DECOMPRESSION AND CIRCULATORY SUPPORT? -FROM CLINICAL EXPERIENCES OF HEARTMATE II WITH SEVERE CONGESTIVE HEART FAILURE PATIENTS-

AND CIRCULATORY SUPPORT? -FROM CLINICAL EXPERIENCES OF HEARTMATE II WITH SEVERE CONGESTIVE HEART FAILURE PATIENTSHiroyuki Tsukui, Steve Winowich, Eileen Stanford, Jeffrey J Teuteberg, Robert L Kormos. Cardiothoracic Surgery, University of Pittsburgh, Pittsburgh, PA; Cardiology, University of Pittsburgh, Pittsburgh, PA. Purpose: Rotary pumps such as the Heartmate II left ventricular assist device (LVAD) (Thoratec Corporation, Pleasanton, CA) are small, nonpulsatile pumps designed for long-term use. However, its capability for providing full cardiac decompression and circulatory support has been questioned and indeed some have felt that the only safe way rotary pumps can be used is in an assistive mode. Methods: Three patients (Ischemic cardiomyopathy: 2, Post-partum cardiomyopathy: 1, ejection fraction: 10–20%) implanted the HeartMate II LVAD were followed using regular transthoracic echocardiography (TTE). Pump rpm, aortic valve opening (AVO), and left ventricular end-diastolic diameter (LVDd) were measured while changing pump rpm. Results: Full cardiac decompression and circulatory support were observed in all three patients. With the increasing of pump rpm, LVDd and the frequency of AVO decreased in inverse proportion. At an appropriate pump rpm setting, the aortic valve closed completely and LVDd decreased to 60–70% of preoperative LVDd without causing suction by the apical cannula. Longterm renal and circulatory function was normal without heart failure symptoms. Considerations: The Heartmate II provides sufficient circulatory support at an appropriate pump rpm setting in patients with severe congestive heart failure. Long-term full circulatory support can be achieved which is a requirement for destination therapy. INITIAL RESULTS WITH THE PEDIATRIC JARVIK 2000 HEART Robert Jarvik, Bartley Griffith, Greg Burgreen, Michael Morrow, Andrew Lewis. Research, Jarvik Heart, Inc., New York, NY; U of Maryland, Baltimore, MD; Mississippi State U, Starkville, MS. Under the NIH program to develop pediatric mechanical circulatory support systems, we have completed design, fabrication, and initial bench testing of the child model pump, an intraventricular axial flow pump connected from apex to aorta like the adult model Jarvik 2000. The device is one third the size and weight of the adult pump. Parameters include: Adult Jarvik 2000: 26 mm diameter x 7.5 cm long, 30cc, 90g, 16 mm diameter aortic graft, 8–12,000 RPM, 1–6 L/min. Pediatric Jarvik 2000: 17.8 mm diameter x 5.5 cm long, 10cc, 35g, 10mm diameter aortic graft, 10–14,000 RPM, 0.5–5 L/min. Computational fluid dynamics run on the initial prototype blade design predicted excellent flow pressure performance and very good pressure recovery by the stators which has been confirmed In Vitro, as shown below. Negligible losses were predicted by CFD at the pump outflow and graft. Modification of the leading edge of the impeller based on the CFD results was made to avoid local cavitation. Other blade design iterations are planned based on the In Vivo findings. Implants in small sheep will begin in February 2005. The system initially utilizes the same controller as the adult model while a smaller controller and battery system are developed.