Aortic Valve Implantation in the Calf: A Successful Approach Using Heartport® Cannulation and Minimally Invasive Techniques
Igor D. Gregoric MD, Daniel Tamez BS, Mehmet N. Karabulut MD, Roberto Cervera MD, Jeff Conger BS, Kazuhiro Eya MD, Didier Lapeyre MD, Branislav Radovancevic MD, O. H. Frazier MD

Aortic valve replacement (AVR) in calves to test mechanical prosthetic valves has not been favored, primarily because of anatomic difficulties. However, the calf constitutes an excellent and vigorous model for both valve and circulatory assist device testing, due to naturally elevated hemodynamic parameters. Recently, an implantation technique was devised in calves for the evaluation of a new mechanical valve in the aortic position. Ten calves (body weight 91 ± 11 kg) underwent AVR with a 21-mm prosthesis via a small left intercostal thoracotomy, with the aid of a Heartport® cannulation device. Intraoperative mortality was 0%, and mean study duration was 42.6 ± 53.7 days. Three calves were killed prematurely (days 0, 2 and 7) for iatrogenic reasons, and three were killed electively (days 11, 13 and 15) due to valve-related complications. Four other animals were electively terminated at 83 ± 61 days (range: 33-172 days). Results show that AVR with a 21-mm mechanical prosthesis can be performed safely in the calf model. Complication-free survival of up to six months can be achieved in the growing calf, provided that the test valve design satisfies minimum hemodynamic and coagulation criteria.