[Long-term results in valve replacement with Björk-Shiley prosthesis. Analysis of life expectancy by relative...

Using the U.S. STS guidelines, I analyzed the results of 389 patients who underwent Björk-Shiley valve (BS valve) replacement at Nippon Medical School over the past 15 years. In addition, I calculated their relative survival rates using the Japanese Abridged Life Table and objectively determined the treatment effects by taking into account the patients' postoperative life expectancy. There were 201 male and 188 female patients, whose mean age at the time of surgery was 52 +/- 12 years. Of these, 151 patients underwent aortic valve replacement (AVR); 185 had mitral valve replacement (MVR); and 53, aortic and mitral valve replacement (DVR). Convexo-Concave models (CC models) were used in 94 patients, and Monosrut models (MS models) in 295. Their cumulative follow-up was 2006 patient-years and their average observation period was 5.2 +/- 3.6 years (complete follow-up in 98% of cases). A total of 32 patients suffered an early death, while 36 suffered a late death. At 10 years after surgery, the actual survival rates were 80.3% for patients who underwent AVR; 81.9% for MVR; and 70.7% for DVR, indicating no significant differences among the three groups (NS). Meanwhile, the relative survival rates at 10 years after surgery were 88.6% for patients who underwent AVR; 88.2% for MVR; and 75.4% for DVR, indicating that AVR was superior to DVR (p < 0.001), with MVR rated between the two. No significant differences were seen among the three groups with respect to the occurrence rate of valve-related complications. The most frequent complications' thromboembolism occurred at a rate of 2.29%/patient-years overall. Strut fractures occurred in two patients using the CC models (0.25%/patient-years), but there were no strut fractures among those using the MS models. While the effect of atrial fibrillation on the subjects' life prognoses was unclear (NS), patients often developed complications related to artificial valves (p < 0.025), and their life prognoses were inferior to those of patients with sinus rhythm. Survivors reported marked improvements in their quality of life, and their late survival rates were satisfactory. However, their life expectancy was inferior to that of the normal population.