Long-term results of aortic valve replacement with a small St. Jude medical valve in Japanese patients

Abstract

Background: The use of small aortic valve prostheses is still controversial because of negative effects caused by residual obstruction of the left ventricular outflow tract. This study evaluated the long-term results after aortic valve replacement with a small valve from St. Jude Medical (St. Paul, MN).

Methods: Between 1980 and 1999, 221 patients underwent isolated aortic valve replacement with a 23-mm or smaller St. Jude Medical valve. The mortality rate and complications were analyzed, echocardiography was performed, and peak pressure gradient, mean pressure gradient, indexed effective orifice area, and left ventricular mass index were measured.

Results: The follow-up rate in the 221 patients was 99.5% (maximum length, 24.1 years; mean, 10.3 years). Patients with a 19-mm valve were mainly women, older, and had smaller body surface areas. Freedom from valve-related death at 20 years was 100%, 86.0%, and 90.2% in patients with 19-, 21-, and 23-mm valves, respectively. There were no significant differences in the actuarial freedom from valve-related deaths. Echocardiography showed significantly higher peak (32.3 mm Hg) and mean pressure gradients (17.6 mm Hg) and a smaller indexed effective orifice area (0.70 +/- 0.15 cm(2)/m(2)) in patients with a 19-mm valve than in those with a 21- or 23-mm valve. Moderate prosthesis-patient mismatch was present in most patients with a 19-mm valve according to one definition; however, the improvements in ejection fraction and left ventricular mass index were significant, and functional recovery (mean New York Heart Association class, 1.3 +/- 0.5; mean specific activity scale, 5.1 +/- 0.8 metabolic equivalents) was satisfactory.

Conclusions: The present long-term results demonstrate that a small St. Jude Medical valve can be advantageously used in most Japanese patients because their body size is generally smaller than that of Western patients. These findings also emphasize that it is not prosthesis size per se that matters but rather the relation between body size and prosthesis size.