Long-term predictors of subsequent cardiovascular events with coronary artery disease and 'desirable' levels of plasma total cholesterol

Abstract

Background. Patients with coronary artery disease (CAD) are at considerable risk for subsequent cardiovascular events. Although hyperlipidemia accentuates the risk, predictors of subsequent events with CAO and desirable total cholesterol (TC) (<5.2 mmol/l) have not been assessed. Methods and Results. A survival analysis was performed in a subset of 740 consecutive patients who underwent diagnostic coronary arteriography between 1977 and 1978. Eight-three men and 24 women with angiographically documented CAD and desirable TC were followed for subsequent cardiovascular events, including myocardial infarction and cardiovascular death. Over a 13-year period, 75% of CAD subjects with reduced high density lipoprotein cholesterol (HDL-C) (<0.9 mmol/l) developed a subsequent cardiovascular event compared with 45% of those with HDL-C ≥0.9 mmol/l (p=O.002). A Kaplan-Meier analysis revealed significantly greater survival from cardiovascular end points in patients with baseline levels of HDL-C ≥0.9 mmol/l (p=0.005). After 11 variables were tested, an age-adjusted Cox proportional-hazards model identified two pairs of independent predictors of subsequent cardiovascular events: they were a left ventricular ejection fraction (LVEF) <35% (relative risk [RR], 6.5; 95% confidence interval [CI], 2.8,15.3;p<0.001) and reduced HDL-C (RR, 2.0; 95% CI, 1.2,3.3; p=0.01) in the first model and LVEF <35% (RR, 6.5; 95% CI, 2.7,15.6; p<0.001) and TC:HDL ratio ≥5.5 (RR, 1.9; 95% CI, 1.1,3.1; p=0.02) in the second model. Conclusions. Low HDL-C (or high TC:HDL-C) is strongly predictive of subsequent cardiovascular events in subjects with CAD, despite desirable TC. As such, identification of this potentially modifiable risk factor should be actively pursued in this high-risk subgroup.