Retention of bioprosthetic valve annulus in mitral prosthetic replacement.

Mitral valve prosthetic replacement carries high mortality rates by modern standards, and mitral bioprostheses are particularly prone to degeneration. Bioprosthetic replacement may be technically difficult when there is calcification of the tissue ingrowth, strut incorporation, or valve-to-annulus size mismatch at the primary operation. A "valve-in-valve" technique is described where the mechanical prosthesis is implanted in the bioprosthetic annulus in order to avoid such difficulties. The results in the first eight patients are presented, showing post-operative Doppler-derived transvalvar mean gradients between 3.9 mmHg and 7.5 mmHg, and estimated valve areas between 1.9 cm2 and 3.5 cm2. All patients are alive at between 20 and 30 months (mean 23.6 months) after operation, they are without serious post-operative morbidity and are in functional class I or II (NYHA classification).