[Mitral valve replacement with the Björk-Shiley monostrut prosthesis: a 4-year clinical experience].

Mitral valve replacement with Björk-Shiley monostrut prostheses was performed in 142 patients, aged 18 to 73 (mean age: 53.8). A group of 101 patients underwent isolated mitral replacement (group A), while both mitral and aortic (in one case tricuspid) valves were replaced in 41 (group B). In 19 of group A patients and in 9 of group B patients a tricuspid annuloplasty was added. Hospital mortality was one case in each group (group A: 1%; group B:2.4%). The cause of death was low output in both cases (i.e. not valve-related). Late mortality occurred in 4 cases (4%) in group A, and in 3 cases (7.3%) in group B (follow-up: 6 to 58 months; mean follow-up: 24 months). Actuarial survival was 93.79% in group A and 89.94% in group B one year after surgery; it was 93.79% in group A and 81.76% in group B after 3 years. All deaths from undetermined causes, as well as any new unexplained neurological deficit or peripheral emboli, were considered to be valve-related: 84.18% of group A patients, as well as 67.90% of group B, were event free after 3 year (actuarial). most valve-related events occurred in the first year after surgery. We observed thromboembolism in 3 cases for each group: one patient in group B had pannus formation over the prosthetic annulus; prosthetic valve endocarditis in 1 case of group A and 2 of group B; significant hemorrhage due to anticoagulant therapy in 1 (group A); one patient in each group died suddenly, 4 and 7 months postoperatively. One group A patient and 2 group B patients were reoperated: a new valve prosthesis was implanted in two patients. Mean transvalvular gradient, as determined by echocardiography, was 3.8 +/- 2.3 (SD) mmHg in the case of isolated mitral replacement. In conclusion, we believe these results are highly encouraging, especially in the isolated mitral replacement group. Björk-Shiley monostrut prosthesis has been demonstrated to be a reliable valve substitute, with an acceptable incidence of complications. No Björk-Shiley monostrut prosthesis structural deterioration was seen, and its hemodynamic behaviour may be considered satisfactory.