The Measurement of the Retrograde Flow Field of Bileaflet Artificial Heart Valves

• Main Authors: HSU, Jui-Lien, 徐瑞蓮
• Other Authors: LU Po-Chien
• Format: Others
• Language: zh-TW
• Published: 1998
• Online Access: http://ndltd.ncl.edu.tw/handle/48882004357467989542

碩士 === 淡江大學 === 水資源及環境工程學系 === 86 === A series of tests were performed on the currently used St. Jude Medical (SJM), CarboMedics (CM), Edwards Tekna modified DuroMedics (DM) and Sorin Bicarbon (SB) bileaflet artificial heart valves. Flow velocity was measured with a laser Doppler Anemometer in order to compare the four valves by their influence towards various retrograde flow fields and as revealed in relative documents, their relation with blood element damage. All experiments were performed with a pulse duplicator simulating the left side of the human circularity system under the following condition: a cardiac out put of 5 L/min, a constant heart rate of 70 beats/min, and pressure wave forms within the physiological range. The measurement points were primarily located at the gaps between the closed leaflets during diastole, between the leaflets and housing ring, and the hinges. Results show that the peak values of reverse velocity of all four valves during diastole are concentrated at the center of the gap between the leaflets Meanwhile, the peak reverse velocity and peak Reynolds shear stress own simultaneously. The average peak reverse velocities of SB, Dm, SJM, and CM are U = -0.50 m/sec, -0.47 m/sec, -0.45 m/sec, and -0.25 m/sec, respectively. SB has the highest peak Reynolds normal and shear stress values, which are 1950 dynes/cm2 and 800 dynes/cm2, followed by DM, SJM, and CM. The peak Reynolds shear stress values of all four valves range from 300 to 800 dynes/cm2, which exceeds the threshold of platelet damage.