In vitro comparison of aortic valve movement after valve-preserving aortic replacement

Objective: In aortic valve regurgitation and aortic dilatation, preservation of the aortic valve is possible by means of root remodeling ( Yacoub procedure) or valve reimplantation ( David procedure). In vivo studies suggest that reimplantation might substantially influence aortic valve-motion characteristics. Evaluation of aortic valve movement in vivo, however, is technically limited and is difficult to standardize. We evaluated the aortic valve-motion pattern echocardiographically in vitro after reimplantation and remodeling. Methods: By using aortic roots of house pigs ( aortoventricular diameter, 22 mm) a Yacoub procedure ( 22-mm graft; Yacoub, n = 5) or a David I procedure ( 24-mm graft; David, n = 5) was performed. Roots after supracommissural replacement ( 22-mm graft; Supra, n = 5) served as control valves. In an electrohydraulic, computer-controlled pulse duplicator the valves were tested at flows of 2, 4, 7, and 9 L/min. Echocardiographically assessed parameters were rapid valve-opening velocity, slow valve-closing velocity, rapid valve-closing velocity, rapid valve-opening time, rapid valve-closing time, ejection time, maximum valve opening, slow valve-closing displacement, and maximum flow velocity. Results: Mean rapid valve-opening velocity and mean rapid valve-closing velocity at a cardiac output of 2 to 9 L/min were fastest in David ( rapid valve-opening velocity: 69 +/- 10 cm/s [ David] vs 39 +/- 4 cm/s [ Yacoub] vs 42 +/- 4 cm/ s [ Supra], P = .0041; rapid valve-closing velocity: 22 +/- 2 cm/s [ David] vs 16 +/- 2 cm/s [ Yacoub] vs 17 +/- 1 cm/s [ Supra], P = .0272), and slow valve-closing velocity was slowest in David ( 0.2 +/- 0.1 cm/s [ David] vs 1.0 +/- 0.3 cm/s [ Yacoub] vs 0.6 +/- 0.1 cm/s [ Supra], P = .0063). With increasing cardiac output, the difference in rapid valve-opening velocity between the groups increased, the difference in slow valve-closing velocity remained unchanged, and the difference in rapid valve-closing velocity decreased. Conclusions: In this standardized experimental setting remodeling of the aortic valve provides significantly smoother valve movements. This might contribute to preservation of a better valve performance during long-term follow-up.