Mid-term survival after cardiac surgery in elderly patients: analysis of predictors for increased mortality

This study examines and quantifies the potential risk factors for increased mid-term mortality in elderly patients (> or = 75 years old) undergoing cardiac surgery. We undertook a retrospective analysis of 840 consecutive elderly patients who underwent cardiac surgery (CABG and/or Valve) between April 1997 and March 2002. Deaths occurring as a function of time were described using the product limit methodology of Kaplan and Meier. Cox proportional hazards analysis was used to identify preoperative risk factors for mortality with hazard ratios (HR). One hundred and sixty-two (19.3%) deaths occurred during the study period, with a total follow-up of 1866 patient years (mean 2.2 years, SD 1.5 years). Observed freedom from death in the elderly patients at 5 years was 71.7%, compared to 70.9% for the age- and sex-matched general population (P=0.252). Multivariate analysis for independent predictors of increased mortality found that renal dysfunction (HR 3.2; P<0.001), valves(s) surgery (HR 1.8; P<0.001), cerebrovascular disease (HR 1.8; P=0.003), and catastrophic state (HR 2.2; P=0.011) were the major risk factors. We have identified and quantified several risk factors, which need to be considered when assessing patients for cardiac surgery.