Leaflet Movement of the ATS Valve in the Aortic Position: Unique Behavior Observed in 19-mm Valves

Background Leaflet opening angles of ATS valves in vivo tend to be less than those reported by the manufacturer, and there is a wide variation in opening angles even among valves of the same size. Methods Leaflet movement of aortic ATS valves was evaluated by cineradiography in 77 patients. The mean period from valve replacement to cineradiography was 40.2 months, and during that period, the ATS valve was replaced due to prosthetic valve obstruction in 1 of the 77 patients. Results In 76 patients with a normally functioning ATS valve, the mean opening angle of 19-mm valves (66.3° ± 2.3°) was significantly less (p < 0.0001) than that of ATS valves 21 mm or larger (72.2° ± 3.8° in 21-mm, 72.4° ± 2.8° in 23-mm, and 72.8° ± 2.9° in 25-mm valves). No significant differences were found in the opening angles of ATS valves 21 mm or larger, and the opening angles exceeded 65° in all 69 patients with valves in this category. In one case of obstruction in a 21-mm valve, the opening angle was 57.5°. The closing angle was 24.9° ± 1.3°, which corresponded well with the manufacturer’s in vitro data. Conclusions The opening angle in the 19-mm ATS aortic valve is significantly less than that in valves 21 mm or larger, and an opening angle of less than 65° probably indicates prosthetic valve obstruction in aortic ATS valves sized 21 mm or larger.