부산대학교 도서관

Objective: To determine normal Doppler and 2D gradients and flow characteristics of the Freestylestentless aortic bioprosthesis related to valve size. BACKGROUND: The Freestylestentless aortic bioprosthesis is one of the newer aortic xenografts. Only limited data are available of the echocardiographic flow characteristics during a mid-term follow-up period of this valve. Therefore valve performance related to valve size was measured during a follow-up period of two years. METHOD: 175 consecutive patients with a Freestyleaortic bioprosthesis underwent an echocardiographic and Doppler examination according to a common protocol. Investigations were done within 4 weeks after operation, after 3 to 6 months, and after 1 and 2 years. RESULTS: With a valve size from 19 to 27 mm mean gradients decreased from 8.0 ± 5.1 mmHg at discharge to 5.8 ± 3.8 mmHg after 3–6 months (p< 0.001). Thereafter gradients remained stable. The performance index, the ratio of the measured effective orifice area in the patient divided by the effective orifice area measured in vitro increased from 69 ± 20% at discharge to 79 ± 29% after one, two and three years. Performance index was especially very high in the smaller sized valves with a performance index of 85 ± 17% for the 21 mm valve. During follow-up mean gradients remained below 10 mmHg even in the 21 mm valve. CONCLUSION: Stentless xenografts have ideal haemodynamics, even in the small aortic root.