[Intraoperative hemodynamics of pyrolytic carbon cambered bileaflet valve replacement in animals]

Pyrolytic carbon cambered bileaflet valve developed by Chengdu University of Technology and Sciences was evaluated for its hemodynamics. The curved surface of the valve leaflet is cylindrical. Under anaesthesia, cardiopulmonary bypass and chemical cardioplegia, a cambered bileaflet valve (i.d. = 16 mm) was replaced at mitral position in each of 12 goats. Before valve replacement, mitral flow rate (MFR) was 74.9 +/- 12.3 ml.sec-1, average valvular pressure drop delta P) 0.56 +/- 0.17 kPa (4.2 +/- 1.3 mmHg) and effective opening area (EOA) of the valve 1.20 +/- 0.18 cm2. After valve replacement, corresponding hemodynamic parameters were 49.3 +/- 12.7 ml.sec-1, 0.46 +/- 0.17 kPa (3.8 +/- 1.3 mmHg) and 0.81 +/- 0.12 cm2 respectively. In our previous report on yak pericardiac heart valve (i.d. = 20 mm) in goats, corresponding hemodynamic parameters after valve replacement were 45.6 +/- 11.8 ml.sec-1, 0.86 +/- 0.32 kpa (6.4 +/- 2.4 mmHg) and 0.65 +/- 0.26 cm2. With comparable mitral flow rate and heart rate (113.6 +/- 19.6 min-1 vs 119.1 +/- 17.1 min-1), the average valvular pressure drop of pyrolytic carbon cambered bileaflet valve is significantly smaller than that of the yak pericardiac valve (P less than 0.001), and the effective opening area is marginally larger than that of the yak pericardiac valve (0.05 less than P less than 0.1). If the same-sized valves of this two kinds are used, the hemodynamic parameter of cambered bileaflet valve would be better than those of yak pericardiac valve. Since the latter valve has been successfully used in patients, the present valve might be applicable in clinical situation.