Impact of statins and beta-blocker therapy on mortality after coronary artery bypass graft surgery

Background: We conducted a retrospective cohort study of patients after first-time isolated coronary artery bypass graft surgery (CABG) and assessed the impact of a discharge regimen including beta-blockers and statin therapy and their relationship to long-term all cause mortality and major adverse cardiovascular events (MACE). Methods: We identified patients age >18 years, undergoing first time isolated CABG from 1993 to 2005. Patients were identified using the Cardiovascular Information Registry (CVIR). We collected follow-up information at 30, 60, 90 days and yearly follow-up. The registry is approved for use in research by the institutional review broad. Results: We identified 5,205 patients who underwent single isolated CABG between January 1993 and December 2005. The mean age was 64.5+/-9.7 years and over 70% were male. There was a significant difference in the low density lipoproteins (LDL) concentration between those with or without statin medications (134+/-41.9 mg/dL) (no statin) vs. 126+/-44.8 mg/dL (with statin), P=0.001. A discharge regimen with statin therapy was associated with and overall reduction in 30 day, 1 year and long-term mortality. In addition, overall the triple ischemic endpoint of death, myocardial infarction (MI) and stroke was also significantly lower in the statin vs. no-statin group. In addition, statin and beta-blockers exerted synergistic effect on overall mortality outcomes short-term and in the long-term. We note that the predictors of overall death include no therapy with statin therapy and age [hazard ratios (HR) 1.1, 95% CI: 1.04-1.078, P<0.001] and presence of renal failure (HR 2.0, P=0.005). The estimated 11-year Kaplan Meier curves for mortality between the two groups starts to diverge immediately post discharge after single isolated CABG and continue to diverge through out the follow-up period. Conclusions: A post-discharge regimen of statins independently reduces overall and 1 year mortality. These results confirm those of earlier studies within a contemporary surgical population and support the current clinical guidelines.