Aortic valve replacement with the freestyle stentless xenograft.

We performed aortic valve replacement with the Freestyle stentless xenograft in 55 consecutive patients requiring a bioprosthesis. Thirty-four were male and 21 female, and all were in New York Heart Association class III to V. Ages ranged from 44 to 87 years (median, 74 years). Fifteen patients required coronary bypass grafts. One required mitral valve replacement (after attempted repair) and another needed repair of both the mitral and tricuspid valves. Four were reoperations. Implantation involved two-thirds transection at the aortic sinotubular junction and insertion of the xenograft cylinder into the aortic sinuses. Ischemic times ranged from 34 to 58 minutes for isolated aortic valve replacement and up to 79 minutes for aortic plus mitral valve replacement. Two patients died in the hospital of left ventricular failure. Survivors underwent echocardiographic assessment of systolic gradients. The mean gradients for valve sizes of 21, 23, 25, and 27 cm were 13, 10, 8, and 6.5 mm Hg, respectively. No patient had more than trivial regurgitation. One died late of left ventricular failure. The Freestyle stentless xenograft is user friendly and can be employed in a calcified root. The "cylinder within a cylinder" method is simple and reproducible and avoids aortic regurgitation. Follow-up has shown excellent hemodynamic function and decreasing gradients.