Which of the following statements are not true?

A. Bioprosthetic valves have a relatively high incidence of hemolysis.

B. Bioprosthetic valves have a lower incidence of postoperative prosthetic valve endocarditis.

C. Mechanical valves develop structural failure after an average of 7 to 10 years.

D. Mortality attributable to warfarin therapy approaches 5% per patient-year

DISCUSSION: Bioprosthetic valves have a relatively low incidence of hemolysis. Bioprosthetic and mechanical valves do not differ significantly in the associated incidences of postoperative prosthetic valve endocarditis. Bioprosthetic valves develop structural failure after an average of 7 to 10 years, whereas mechanical valves have a life span of well beyond 10 years. The mortality attributable to warfarin therapy approaches 1% per patient-year.