Cineradiographic functional evaluation of the Björk-Shiley monostrut prosthesis:A Follow-up Study of 46 Consecutive Patients

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Abstract
In 46 patients, 51 Björk-Shiley monostrut valves were studied with high-speed cineradiography 9 months after implantation. Each valve was viewed in lateral, frontal and oblique projections for 10-12 heart beats. In the aortic valves the opening time was 0.04-0.067 (mean 0.052) and closing time 0.04-0.067 (mean 0.046) sec. In all these valves the maximum opening angle was 70°. Disc rotation could be monitored in 29/31 valves, and during 10 heart beats averaged 20°. Disc slide of 2.0-2.5 mm was seen in 27/31 valves. It occurred during the last 40-50° of opening and the first 20-40° of closing. In mitral valves with sinus rhythm (12/20), the opening time was 0.053-0.106 (mean 0.073) and closing time 0.040-0.106 (mean 0.061) sec. Mean disc rotation (recorded in 17/20 valves) during 10 heart beats was 25°, and disc slide of 2.0-2.5 mm was found in all but one case, mainly during the last 50° of opening and the first 30° of closing. The valve opened to 70° in all but one patient, in whom the disc clearly impinged against the left ventricular wall and opened only to 35-50° at rest. At reexamination a year later the patient was asymptomatic, in sinus rhythm, and the disc had regained full movement with 70° opening.