頁籤選單縮合
題 名 | Measurement of Retrograde Flow Field of Bileaflet Artificial Heart Valves |
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作 者 | Lu,Po-chien; Hsu,Jui-lien; Chu,Shu-hsun; | 書刊名 | 醫學工程 |
卷 期 | 11:1 1999.02[民88.02] |
頁 次 | 頁11-18 |
分類號 | 410.1644 |
關鍵詞 | Bileaflet artificial heart valve; In vitro test; Retrograde flow; Reynolds stresses; Thrombosis; |
語 文 | 英文(English) |
英文摘要 | This study focuses on a series of in-vitro tests on retrograde flow fields of four clinically- used artificial bileaflet aortic valves, St. Jude Medical (SJM), CarboMedics (CM), Edwards Tekna modified DuroMedics (DM), and Sorin Bicarbon (SB). The flow fields of the valves were measured with a laser Doppler anemometer (LDA) at the upstream area near the valves. The measurement points were concentrated at the locations where the greatest retrograde flow occurs when the leaflets closed, which are the gaps in between the leaflets, in between the leaflets and housing ring, and at the hinges. The valves were placed inside a circulatory mock loop in which the heart rate was set at 70 beats per minute, the cardiac output was maintained at 5 liters per minute, and the aortic pressure wave forms were kept within the physiological range. The valves were compared according their mean velocities, Reynolds stresses, as well as their effects on retrograde flow fields and blood cell damage. The mean velocities of the retrograde flow fields of SJM, CM, DM and SB valves all reach maximum values at the center of the gap between the closed leaflets during the early stages of diastole. SB has the greatest mean velocity and principle Reynolds shear stress values, followed by DM, SJM, and CM. The maximum Reynolds shear stress values of all four valves exceed the threshold of platelet damage, thus increasing the possibility of thrombosis. |
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