Hemodynamic features of the freestyle aortic bioprosthesis compared with stented bioprosthesis

Background. The Freestyle prosthesis is a new stentless aortic bioprosthesi s. Anticipated benefits are improved hemodynamics and increased longevity. Methods. Doppler echocardiograms were performed early and at 3 to 6 months, 1 year, and 2 years after operation in 157 patients (69 men, 88 women, age d 48 to 85 years) with this prosthesis, and results were compared with hemo dynamic data in patients with Intact and Mosaic stented bioprostheses. Results. Distinctive features of the prosthesis compared with stented prost heses are (1) an increase in effective orifice area (+0.15 +/- 0.26 cm(2); p < 0.05) and a decrease in mean gradient (-3.5 +/- 4.0 mm Hg; p < 0.001) d uring the first 3 to 6 months postoperatively and stabilization thereafter; (2) a markedly lower mean gradient at 1 year after operation (average, 6 /- 4 mm Hg) than in stented prostheses (Intact, 22 +/- 8 mm Hg; Mosaic, 12 +/- 6 mm Hg); (3) in contrast to stented prostheses, in vivo effective orif ice areas much lower (-0.91 +/- 0.35 cm(2)) than those calculated in vitro; (4) as in stented prostheses, the indexed effective orifice area (cm(2)/m( 2)) is the best predictor (r = 0.77 at 1 year) of the mean gradient after o peration; and (5) similar incidence of aortic regurgitation (trivial or mil d, 34% versus 29% in Intact). Conclusions. The hemodynamics of the Freestyle are very satisfactory and re present a marked improvement in comparison to stented prosthesis. (C) 1998 by The Society of Thoracic Surgeons.