Influence of cholesterol level on long-term survival and cardiac events after surgical coronary revascularization

OBJECTIVE: Statins have been shown to delay the inevitable progression of atherosclerosis in native coronaries and saphenous vein grafts, thereby reducing ischemic events after surgical coronary revascularization. However, there is significant controversy as to whether titrating statin therapy to concrete cholesterol targets is appropriate. METHODS: A single-center retrospective analysis of 309 consecutive patients who underwent isolated coronary artery bypass graft in 2007 and 2008 was performed. Measurements of lipid profile subcomponents, namely total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglycerides, in mmol/L, were obtained by retrospective review of electronic health records. The primary end point was cardiac death. The secondary end point was the composite of cardiac events, including cardiac death, nonfatal myocardial infarction, hospitalization for unstable angina, and target lesion revascularization. Database lock date was August 15, 2020. RESULTS: The median follow-up duration was 12.5 years. Cardiac death occurred in 6.8% of the cohort. Cardiac events occurred in 21.7% of the cohort. New-onset myocardial infarction occurred in 8.7% (n = 27), of which 48.1% (n = 13) underwent repeat revascularization. A 2-level nested Cox proportional hazards regression model was constructed to determine whether cholesterol target attainment was independently associated with cardiac events. After risk adjustment, LDL-C, non–HDL-C, total cholesterol (TC), and TC/HDL-C ratio were independently associated with cardiac death. In receiver operating characteristics analyses, the optimal cut-off values for non–HDL-C, LDL-C, and TC/HDL-C ratio were 3.2 mmol/L, 2.3 mmol/L, and 3.5, respectively. CONCLUSIONS: Exposure to elevated LDL-C and non–HDL-C cholesterol levels independently predicted long-term cardiac death after coronary artery bypass graft.