Background and aim of the study: The St. Jude Medical Silzone valve was withdrawn from the market after an interim analysis of the AVERT study revealed a 2.76% incidence of paravalvar leakage leading to valve re-replacement, compared with only 1.02% in the control group. Additionally, an increased risk for thromboembolic complications was reported in different series of patients.
Methods: To monitor the consistency of these reports, the incidence of thromboembolic complications and paravalvar leakage was investigated in 113 patients who received a Silzone valve at the authors' institution, compared with 101 patients who, immediately prior to the Silzone group, received a conventional valve.
Results: No difference was found in the incidence of either thromboembolism or paravalvar leakage after either Silzone or conventional valve replacement.
Conclusion: Differences between the AVERT study and the present study might reflect differences in operative technique or in patient groups, but this as yet is unknown. To clarify the prospects of the estimated 36,000 patients with Silzone valves world wide, further research should aim at identifying possible unique features of patient groups with a higher risk of paravalvar leakage leading to valve explantation. In brief, an increased rate of paravalvar leakage and/or thromboembolism does not apply to either valve replacement groups.