Twelve-Year Comparison of a Bjork–Shiley Mechanical Heart Valve with Porcine Bioprostheses

WE have previously reported the initial results of a randomized trial begun in 1975 that compared mechanical with porcine prostheses for heartvalve replacement. After a median follow-up of 5.6 years, there were no significant differences in the rates of overall survival, valve failure, or valve-related complications. 1 The Department of Veterans Affairs (formerly the Veterans Administration) began a similar study in 1977, and also found no significant difference in survival after a mean follow-up of five years. There was, however, a significantly lower incidence of valve-related complications in patients receiving a porcine prosthesis, mainly because patients receiving a mechanical prosthesis had . . .