Risk factors for morbidity and mortality in mitral valve replacement

Abstract

Risk factors of operative mortality and long term survival wereidentified in 219 patients who underwent mitral valve replacement (MVR)using Bjork-Shiley mechanical prostheses. Early mortality was 7.3%. Theaccumulated follow-up time was 1134 patient-years, and the 5-year survivalfor the total cohort was 78 +/- 3%. Independent prognostic factors of earlymortality were poor NYHA class, which carried a relative risk (RR) of 3.2,and ischaemic aetiology, with a RR of 2.2. Ischaemic aetiology was the solepredictor of heart pump failure requiring intra-aortic balloon pump support(RR = 2.7). Independent risk factors of total mortality (early and late)were male sex (RR = 2.3), NYHA class III-IV (RR = 2.4), presence of mitralregurgitation (RR = 3.2) and relative heart volume (RR = 1.6 for a 800ml/m2 size compared to a heart of 550 ml/m2). Our results underline theimportance of patient-related factors in MVR, and indicate that care isneeded in comparing the quality of MVR from different institutions withrespect to mortality and morbidity. The results of MVR are palliativerather than curative except in female patients with NYHA class II functionand mitral stenosis, in whom cure was attained.