Relative survival of patients after heart valve replacement

Long-term results after prosthetic heart valve replacement are usually presented in actuarial terms, which do not take into account the background mortality of the general population. The calculations of the relative survival, which is the ratio between the observed survival in a group of patients during a specified time interval and the survival expected from the general population experience, permit correction for important demographic variables. We have analysed the long-term relative survival rates in a consecutive series of 841 Norwegian patients who, on the basis of clinical symptoms, underwent aortic (AVR, n = 617), mitral (MVR, n = 146), and double (AVR + MVR, n = 78) valve replacement between June 1977 and January 1985. The follow-up was closed on May 1st 1986, was 100% complete and included 2056 patient-years. The actuarial survival data for the total cohort was 75.1%, and for AVR, MVR and DVR, 77.9, 69.7 and 63.0%, respectively. The corresponding figures for the relative survival were 83.5, 87.0, 76.6 and 69.1%, respectively. Within the subgroup undergoing AVR, our analysis demonstrated a poor prognosis in those who were operated for pure aortic regurgitation or endocarditis, as well as in those who received the smallest valve size prosthesis due to a narrow aortic root. In this analysis, as in the analysis of the total material, we observed that the differences between survival in the patients and in the general population were of smaller magnitude when based on relative survival rates than when analysed in the standard (actuarial) way.(ABSTRACT TRUNCATED AT 250 WORDS)