Thromboembolism and mechanical heart valves: A randomized study revisited

Background. This study was designed to revise and substantiate previous inferences, based on short-term follow-up, about differences in the incidence of anticoagulant-related events after heart valve replacement among patients who had been randomly assigned to receive either a Bjork-Shiley, Edwards-Duromedics. or Medtronic-Hall mechanical heart valve prosthesis. Methods. Intermediate-term follow-up to January 1995 was completed in 418 of 419 patients randomized to receive one of three types of heart valve prostheses between January 1982 and January 1987. Median follow-up was 98.5 months. Multivariable analysis in the hazard function domain was performed to identify factors that influenced the incidence of time-related thromboembolism and bleeding. These findings were compared with those made previously after a median follow-up of 37.5 months. Results. No differences were found among the three prostheses in rates of anticoagulant-related hemorrhage. However, the incidence of thromboembolism was higher after mitral valve replacement among patients who had received the Medtronic-Hall prosthesis (linearized rate, 5.4% per patient year: 70% confidence interval, 4.0% to 7.1%), compared with Edwards-Duromedics (1.3%; 70% confidence interval, 0.4% to 3.0%) and Bjork-Shiley prostheses (1.2%; 70% confidence interval, 0.6% to 2.2%). Conclusions. At long-term follow-cap, in contrast to the findings at short-term follow-up, patients with either Bjork-Shiley or Edwards-Duromedics prostheses had low rates of thromboembolism, whereas higher rates occurred in patients with a Medtronic-Hall prosthesis in the mitral position. (Ann Thorac Surg 1998;66:101-7) (C) 1998 by The Society of Thoracic Surgeons

REPAIR OF AORTIC COARCTATION IN INFANTS

Fifty-three consecutive infants younger than 2 years underwent coarctation repair. A recoarctation occurred in 11 infants (21%). To determine variables associated with recoarctation, we entered preoperative and operative data into a multivariate stepwise logistic regression analysis. Patient weight was an incremental risk factor for recoarctation instead of age, in contrast to previously published studies. Furthermore, the residual gradient after the operation was a strong incremental risk factor. This risk factor was even more significant when expressed as a ratio of the systolic arm pressure, which takes background hemodynamics into account. Because weight is a more significant risk factor than age, we conclude that deferring operation is indicated only when the infant gains weight. Furthermore, a residual gradient is more important in the hemodynamic setting of a lower systolic arm pressure