Background and aim of the study: Permanent silver (Silzone) coating of the sewing cuff of St. Jude Medical prosthetic heart valves may reduce the rate of prosthetic valve endocarditis (PVE). However, the incidence of paravalvular leaks and stroke in patients after implantation of Silzone-coated heart valve prostheses is largely unknown.
Methods: Complications were analyzed among 126 consecutive patients (78 males, 48 females; mean age 64.7 years; range: 40-80 years) who received Silzone-coated prostheses at our institution between February 1998 and December 1999. Among patients, 94 had aortic valve replacement, 29 mitral valve replacement, and three had aortic and mitral valve replacement. Concomitant cardiac procedures (mainly coronary bypass) were performed in 47 patients (37.3%).
Results: Hospital mortality was 1.6% (2/126) and freedom from valve-related mortality 99.2+/-0.9%. Total follow up was 137.4 patient-years, and 98.4% complete. Strokes or transitory ischemic attacks (TIAs) occurred in four cases (two strokes, two TIAs; stroke rate 1.5%/year; 95% CI 0.4-2.6%/year; stroke+TIA rate 3%/year; 95% CI 0.4-5.25%/year). There was no case of prosthetic valve dysfunction or PVE. Freedom from reoperation due to procedure-associated complications was 97.6% (one aortic dissection, two major bleeds). Paravalvular leak was detected in 19 cases, and graded trivial or mild in 17 cases (11 grade 0-I, six grade I), and moderate in two cases (grade I-II in one, grade II in one). No patient needed reoperation due to paravalvular leak. Left ventricular (LV) function was normal in 80 cases, but was impaired mildly in 20 cases, moderately in 16, and severely in eight. Bicycle exercise testing in 92 patients (73%) showed median exercise performance (81.4+/-23.9% of normal) after correction for age and weight. Cerebral magnetic resonance imaging was performed in 64 patients (50.8%); median MRI score was 2.0+/-1.8 according to a 12-scaled score system.
Conclusion: The overall incidence of echocardiographic paravalvular leak graded more than trivial or mild was low (1.6%) in patients followed for a mean of 1.1+/-0.5 years (range: 1-27 months) after valve replacement with Silzone-coated heart valve prostheses. No patient required reoperation due to paravalvular leak; moreover, the stroke rate (1.5%/year) was low in these patients. The present data indicated no significant disadvantages or higher rate of complications related to silver coating compared with other, non-silver-coated prostheses. Future investigation is needed to determine long-term outcome.