Clinical experience with the Ionescu-Shiley xenograft valve: four to five-year follow-up.

Between January 1977 and July 1981, 132 Ionescu-Shiley xenografts were implanted in 124 patients. Early and late mortality was 13.7% (17/124) and 9.2% (10/107), respectively. Cumulative survival rates at 4 to 5 years were 76% (aortic) and 84% (mitral). Thromboembolic analysis showed 0.72 episodes per 100 patients per year, without chronic anticoagulation. The thromboembolism free rates were 96.8% (mitral) and 100% (aortic); 75% of the mitral patients were in atrial fibrillation. No primary valve dysfunction was detected. In the aortic position (8 patients with valve stent diameter from 19 to 25 mm), the mean peak systolic gradient pressure was 10 +/- 5.5 mm Hg, and calculated valve surface areas were 1.6 +/- 0.5 cm2 at rest and 2 +/- 0.1 cm2 after exercise. A satisfactory correlation between catheterization-derived valve area (from hemodynamic data) and valve stent diameter was obtained (r = 0.94). In the mitral position, the mean diastolic gradient pressure was 4.7 +/- 3.1 mm Hg at rest and 13.8 +/- 0.9 after exercise with the 27 mm xenograft. The corresponding calculated surface areas were 2.8 +/- 6 cm2 and 3 +/- 0.8 cm2. The present data show minimal thrombogenicity without chronic anticoagulation, even in patients with atrial fibrillation or enlarged left atrium and advantageous hemodynamic characteristics, particularly in those with small aortic annuli.