機械的人工弁の流れ場の解析 : Starr-Edwards, Bjork-Shiley c-c, 及びSt. Jude Medical弁の比較

抄録

Three typical mechanical heart valves (Starr-Edwards, Bjork-Shiley c-c and St. Jude Medical) have been tested in the mitral position under pulsatile flow conditions, The test program included measurements of velocity and turbulent stresses at six downstream locations. The study was carried out using a sophisticated cardiac simulator in conjunction with a highly sensitive two-component laser Doppler anemometer system. The continuous monitoring of parametric time histories revealed useful details about the complex flow and also helped established location and time of the peak parameter values. Based on the experimental data, the following general conclusions can be drawn: (i) all 3 valve designs generated elevated turbulent stresses during acceleration and peak flow phases, presenting a possibility of thromboembolism, and perhaps, hemolysis; (ii) valve configuration and valve orientation significantly affect the flow characteristics; (iii) the Starr-Edwards valve with relatively a small opening area shows lower turbulent stresses; and (iv) the bileaflet design of the St. Jude Medical valve is also associated with lower turbulent stresses, as compared to the Bjork-Shiley c-c valve.