Summary
Between 1974 and 1976, 150 patients were operated upon for isolated mitral valve replacement using Björk-Shiley Standard (BSM), Lillehei-Kaster (LKM), and Starr-Edwards (type 6120) (SEM) prostheses in a prospective, randomized study. These patients have now been followed-up for 5 to 7 years postoperatively.
Cumulative survival rates after 5 years were not significantly different between the groups. According to the grading of the New York Heart Association (NYHA), clinical improvement up to one class was achieved in about 60% of the patients, while an improvement of more than one NYHA-class was rare.
Thromboembolic complications were significantly more frequent after Starr-Edwards than after Björk-Shiley implantation, while the incidence of major hemorrhagic complications due to the anticoagulant therapy showed no intergroup differences. Chronic intravascular hemolysis, indicated by LDH and haptoglobin levels, was more significant after Lillehei-Kaster and Starr-Edwards mitral valve replacements than after Björk-Shiley implantation.
While, at the hemodynamic control examination, cardiac index remained at the lower normal value level in each of the 3 groups, rnean pulmonary artery pressure (PAP) and mean left atrial pressure were significantly reduced. After 5 years, PPA was significantly lower in the Björk-Shiley than in the Lillehei-Kaster and the Starr-Edwards groups. Without intergroup differences in diastolic mitral flows per second, average diastolic pressure drop after Björk-Shiley implantation was significantly lower (5.5 ± 2.3 mmHg) than after Lillehei-Kaster (7.5±3.2 mmHg) or Starr-Edwards replacements (6.8 + 2.6 mmHg). Valve orifice areas, calculated by Gorlin formula, were larger in the Björk-Shiley group (1.9 ± 0.5) than after Lillehei-Kaster (1.5±0.6) and Starr-Edwards implantations (1.7 ± 0.6 cm2).
Regarding postoperative complications and hemodynamic features, better results could be achieved after randomized Björk-Shiley than after Lillehei-Kaster and Starr-Edwards implantations.
Key words
Mitral valve replacement - Complications following mitral valve replacement - Björk-Shiley prosthesis - Starr-Edwards prosthesis - Hemodynamics
