title: The Björk-Shiley and Ionescu-Shiley heart valve prostheses. In vitro comparison of their hydrodynamic performance in the mitral position.
abstract: Shiley Scientific Inc., are now manufacturing six types of prosthetic heart valves. There are four different models of the Björk-Shiley and two versions of the Ionescu-Shiley pericardial heart valve. The Björk-Shiley valves are those with a spherical disc, 60 degrees and 70 degrees opening convexo-concave discs, and the latest monostrut model. The Ionescu-Shiley valves are the original titanium stent model and the latest Delrin stent low profile model. The hydrodynamic performance of these valves in the mitral position all having a tissue annulus diameter of 29 mm, has been measured. Tests were performed in a pulse duplicator simulating sinus rhythm at heart rates of 60, 80 and 120 beats per minute (BPM) with a stroke volume (SV) between 69 and 73 ml and at a heart rate of 200 BPM with SV between 27 and 34 ml. The latter test condition simulates a situation of supraventricular tachycardia. Mean transmitral pressure, regurgitation, and transmitral energy loss for each valve under each set of conditions were compared. All the Björk-Shiley valves were tested in two orientations with the major flow orifice oriented either anteriorly (A) or posteriorly (P). For all valves, it was found that the major contribution to the total transmitral energy loss, most apparent at 200 BPM, was caused by regurgitation and that at 60, 80 and 200 BPM, the forward flow phase contributed only a small amount to the total energy loss. The small intentional leakage across the Björk-Shiley valves is minor compared to closing regurgitation but is a major contributor to transmitral energy loss.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D002302:Cardiac Output; D005069:Evaluation Studies as Topic; D005990:Glycerol; D006339:Heart Rate; D006350:Heart Valve Prosthesis; D008943:Mitral Valve; D008944:Mitral Valve Insufficiency / Q000503:physiopathology; D008955:Models, Cardiovascular; D012965:Sodium Chloride; D013318:Stroke Volume; D013610:Tachycardia / Q000503:physiopathology
chemical_list: D012965:Sodium Chloride; D005990:Glycerol