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; group Y, n = 5) or a David I procedure (24-mm graft; group D, n = 5) was performed. Roots after supracommissural replacement (22-mm graft; group C, 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 group D (rapid valve-opening velocity: 69 +/- 10 cm/s [group D] vs 39 +/- 4 cm/s [group Y] vs 42 +/- 4 cm/s [group C], P = .0041; rapid valve-closing velocity: 22 +/- 2 cm/s [group D] vs 16 +/- 2 cm/s [group Y] vs 17 +/- 1 cm/s [group C], P = .0272), and slow valve-closing velocity was slowest in group D (0.2 +/- 0.1 cm/s [group D] vs 1.0 +/- 0.3 cm/s [group Y] vs 0.6 +/- 0.1 cm/s [group C], 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.