Regurgitation of prosthetic heart valves: dependence on heart rate and cardiac output.
Prosthetic heart valves exhibit closure and leakage backflow; however, no well-controlled study to evaluate the influence of factors such as cardiac output and heart rate on backflow has been reported to date. Four clinically used prosthetic aortic valves (size 27 mm)--St. Jude Medical, Björk-Shiley Spherical Disc, Björk-Shiley Convexo Concave, and Starr-Edwards model 1260--were studied in the aortic chamber of a pulse duplication system at heart rates of 50, 80, 110, and 140 beats/min, cardiac output of 2, 4, 6, and 8 liters/min, and mean aortic pressure of 100 mm Hg. Regurgitation was calculated in percentage and found to vary directly with heart rate and inversely with cardiac output. The range of values obtained were 5.5% for the Starr-Edwards model 1260 valve at 110 beats/min and 8 liters/min, to 37.5% for the Björk-Shiley Convexo Concave valve at 140 beats/min and 2 liters/min. Regurgitation was also calculated in milliliters/stroke and ranged from 3.4 ml/stroke for the Starr-Edwards model 1260 valve at 140 beats/min and 2 liters/min, to 17.3 ml/stroke for the Björk-Shiley spherical disc valve at 50 beats/min and 2 liters/min. Regurgitation associated with prosthetic heart valves may present a problem clinically, particularly under conditions of low cardiac output and tachycardia.
D002302:Cardiac Output; D003326:Coronary Circulation; D006339:Heart Rate; D006350:Heart Valve Prosthesis / Q000009:adverse effects; D006801:Humans; D008955:Models, Cardiovascular; D011474:Prosthesis Design