Tricuspid valve replacement : porcine bioprostheses and mechanical prostheses. Discussion

The clinical performance of tricuspid valve replacement with bioprostheses and mechanical prostheses was assessed in a series of 5,489 total valve replacement operations performed from 1975 to 1992. There were 97 (1.8%) tricuspid valve replacements in 94 patients (16 men, 78 women) with a mean age of 55.4 ± 13.8 years. Bioprostheses (mean patient age, 55.9 ± 14.1 years) were used in 83 operations and mechanical prostheses (mean patient age, 52.1 ± 11.9 years) were used in 14 operations. There were 30 isolated tricuspid valve replacements and 67 tricuspid valve replacements incorporated in multiple valve replacements. The total cumulative follow-up was 360 patient-years (bioprostheses, 321 years ; mechanical prostheses, 39 years) (96.8% complete). The mean follow-up was 3.7 years (bioprostheses, 3.9 years ; mechanical prostheses, 2.8 years) (p = not significant). The early mortality was 14.4% (bioprostheses, 14.5% ; mechanical prostheses, 14.3%) (p = not significant) (isolated replacement, 13.3% ; multiple replacement, 14.9%). The late mortality was 9.2% per patient-year (isolated replacement, 12.2% per patient-year ; multiple replacement, 7.9% per patient-year). The freedom from structural valve deterioration at 5 and 7 years was 100% for mechanical prostheses and 97.1% ± 2.9% for bioprostheses (p = not significant). For isolated tricuspid valve replacement, the freedom from structural valve deterioration for bioprostheses was 90.9% ± 8.7% at 5 years and at 7 years (p = not significant). For the mechanical prostheses, the freedom was 100%. The freedom from valve-related reoperation for mechanical prostheses was 86.7% ± 12.4% at 5 and 7 years ; for bioprostheses, it was 97.1% ± 2.9% at 5 years and 92.5% ± 5.2% at 7 years (p = not significant). There was one reoperation among the isolated replacements with bioprostheses (one of four), and freedom from reoperation for bioprostheses was 90.9% ± 8.7% at 5 years and at 7 years (p = not significant). With multiple tricuspid valve replacement, the freedom from reoperation for mechanical prostheses was 84.6% ± 14.2% at 5 and 7 years ; for bioprostheses, it was 100% at 5 years and 93.8% ± 6.1% at 7 years (p = not significant). Thrombosis was different (p < 0.05) : for overall tricuspid valve replacement, the freedom from thrombosis for mechanical prostheses was 90.9% ± 8.7% at 5 and 7 years and for bioprostheses, it was 100%. In the tricuspid valve multiple replacement group, the freedom from thrombosis for mechanical prostheses was 88.9% ± 10.5% at 5 and 7 years and for bioprostheses, it was 100% at both times (p = not significant). Tricuspid valve replacement carries a high early and late mortality rate. Bioprostheses are recommended because of the low rate of structural valve deterioration and avoidance of thrombosis.