In Vitro Study of the Correlation between the Aortic Flow Field Affected by the Bileaflet Mechanical Valves and Coronary Circulation

摘要

Three bi-leaflet prostheses, the St. Jude Medical (SJM) and the On-X valves with straight leaflets and the MIRA valves with curved leaflets were tested in the aortic position under pulsatile-flow condition to find the design and other influences on aortic flow field and coronary circulation. The flow field affected by the valve-installed orientations, leaflet shapes, and valve designs were analyzed using Dynamic PIV system. Direct measurement of the coronary flow using ultrasonic flow meter was used to monitor coronary flow. Detailed chronological comparison of the flow fields downstream of the aortic valve and inside the sinus of valsalva and coronary flow revealed the overall valve effect on the flow and possible influence on the coronary flow.Newer IVIIRA and On-X valves showed strong flow through the central orifice. The SJM and the newer On-X valve generate stronger circulatory flow inside the sinus of valsalva when valve orientation is set at 180° while the MIRA valve with curved leaflet generates stronger circulatory flow inside the sinus of valsalva when valve orientation is set at 90°. Coronary flow clearly shows the increase of flow rate when the circulatory flow inside the sinus of valsalva increase. This possibly indicate the positive correlation exist between the circulatory flow inside the sinus of valsalva and the coronary flow.