Seven-year results with the St Jude Medical Silzone mechanical prosthesis

Objective

The Artificial Valve Endocarditis Reduction Trial was stopped on January 21, 2000, due to a higher incidence of paraprosthetic leak in the St Jude Medical Silzone prosthesis compared with the conventional prosthesis. The Artificial Valve Endocarditis Reduction Trial investigators reported the 2-year results in 2002. This retrospective study assessed the influence on thromboembolism and paraprosthetic leak to 7 years.

Methods

A total of 253 patients had 254 operations: 80 aortic valve replacements, 139 mitral valve replacements, and 35 multiple replacements with placement of Silzone prostheses. The mean age was 58.6 years (range 21–84 years, median age 59.8 years), and there were 126 women (49.8%) and 74 concomitant procedures (coronary artery bypass 28.9%).

Results

Major paraprosthetic leak (repair, re-replacement, or mortality) occurred in 10 of the original procedures after 30 days (3 aortic valve replacements, 3 mitral valve replacements, 4 multiple replacements). Nine occurrences in 8 patients—5 early (≤2 years) and 4 late (>2 years)—were managed. Seven were managed with definitive re-replacement. One was an early nonoperative fatality. There was 1 late fatality after the second late paraprosthetic leak reoperation. One of the 10 procedures occurring after 2 years had mild to moderate aortic valve replacement paraprosthetic leak managed as an incidental re-replacement at the time of correction of supra valvular patch stenosis. One additional occurrence, in addition to the 8 patients (<30 days), was considered a technical error and not related to the Silzone prosthesis and was replaced with a Silzone prosthesis. The linearized rate of paraprosthetic leak within the first 2 years of follow-up was 1.3%/patient-year and after 2 years was 0.4%/patient-year. The linearized occurrence rate for major thromboembolism was 0.42%/patient-year for aortic valve replacement and 1.71%/patient-year for mitral valve replacement.

Conclusions

Paraprosthetic leak with the St Jude Medical Silzone prosthesis was managed both during the early (≤2 years) and late (>2years) intervals with re-replacement. Late managed events may be manifestations of earlier occurring paraprosthetic leak. Follow-up echocardiograms should meet standards of care, 6 to 12 months after surgery and at the slightest suspicion of dysfunction. There is no advanced continuing risk of the St Jude Medical Silzone prosthesis.

CTSNet classification: 35

Abbreviations and Acronyms: AVERT, Artificial Valve Endocarditis Reduction Trial, AVR, aortic valve replacement, MR, multiple replacements, MVR, mitral valve replacement, OPC, Objective Performance Criteria, PPL, paraprosthetic leak