Evolution of the surgical approach for replacement of degenerated mitral bioprostheses

Primary tissue failure is the most frequent indication for reoperation in patients with a mitral bioprosthetic valve (MBPV). Complete excision of the bioprosthesis is time-consuming and may be complicated by cardiac rupture at the atrioventricular junction or the posterior left ventricular wall where a strut is embedded, injury to the circumflex coronary artery, or late perivalvular leak. A new approach to avoid these complications by excision of only the bioprosthetic tissue and attachment of a St. Jude valve (SJV) to the intact stent has been developed and evaluated.

The results of replacement of failed MBPV with SJV in 71 consecutive patients between September 1992 and December 1994 were analyzed; 57 patients had the valve replaced after complete excision and 14 with stent preservation. The demographic and clinical profiles of the two groups were similar.

Among patients undergoing complete excision of the MBPV, operative mortality was 14% (8 of 57), with 12 late deaths and a 5-year survival of 75% and three late perivalvular dehiscences requiring another operation. No operative deaths occurred in the intact stent group and one late death (cancer), and all the remaining patients are doing well without perivalvular leaks or other complications.

Leaving the MBPV stent intact eliminates the need for extensive dissection, thus shortening and simplifying the procedure and diminishing its attendant mortality and morbidity. It offers a safe and logical approach to replacement of a degenerated MBPV with a SJV of comparable size.