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BACKGROUND High-density lipoprotein (HDL) may provide cardiovascular protection by promoting reverse cholesterol transport from macrophages. We hypothesized that the capacity of HDL to accept cholesterol from macrophages would serve as a predictor of atherosclerotic burden. METHODS We measured cholesterol efflux capacity in 203 healthy volunteers who underwent assessment of carotid artery intima–media thickness, 442 patients with angiographically confirmed coronary artery disease, and 351 patients without such angiographically confirmed disease. We quantified efflux capacity by using a validated ex vivo system that involved incubation of macrophages with apolipoprotein B–depleted serum from the study participants. RESULTS The levels of HDL cholesterol and apolipoprotein A-I were significant determinants of cholesterol efflux capacity but accounted for less than 40% of the observed variation. An inverse relationship was noted between efflux capacity and carotid intima–media thickness both before and after adjustment for the HDL cholesterol level. Furthermore, efflux capacity was a strong inverse predictor of coronary disease status (adjusted odds ratio for coronary disease per 1-SD increase in efflux capacity, 0.70; 95% confidence interval [CI], 0.59 to 0.83; P<0.001). This relationship was attenuated, but remained significant, after additional adjustment for the HDL cholesterol level (odds ratio per 1-SD increase, 0.75; 95% CI, 0.63 to 0.90; P = 0.002) or apolipoprotein A-I level (odds ratio per 1-SD increase, 0.74; 95% CI, 0.61 to 0.89; P = 0.002). Additional studies showed enhanced efflux capacity in patients with the metabolic syndrome and low HDL cholesterol levels who were treated with pioglitazone, but not in patients with hypercholesterolemia who were treated with statins. CONCLUSIONS Cholesterol efflux capacity from macrophages, a metric of HDL function, has a strong inverse association with both carotid intima–media thickness and the likelihood of angiographic coronary artery disease, independently of the HDL cholesterol level. (Funded by the National Heart, Lung, and Blood Institute and others.)

full . The American Heart Association makes every effort to avoid any actual or potential conflicts of interest that may arise as a result of an outside relationship or a personal, professional, or business interest of a member of the writing panel . Specifically, all members of the writing group are required to complete and submit a Disclosure Questionnaire showing all such relationships that might be perceived as real or potential conflicts of interest .

Summary Aim To determine whether an association exists between mean platelet volume (MPV) and acute myocardial infarction (AMI) and other cardiovascular events. Platelet activity is a major culprit in atherothrombotic events. MPV, which is widely available in clinical practice, is a potentially useful biomarker of platelet activity in the setting of cardiovascular disease. Methods and Results We performed a systematic review and meta-analysis investigating the association between MPV and AMI, all-cause mortality following myocardial infarction, and restenosis following coronary angioplasty. Results were pooled using random-effects modeling. Pooled results from 16 cross-sectional studies involving 2809 patients investigating the association of MPV and AMI indicated that MPV was significantly higher in those with AMI than those without AMI [mean difference 0.92 fL, 95% confidence interval (CI) 0.67–1.16, P < 0.001). In subgroup analyses, significant differences in MPV existed between subjects with AMI, subjects with stable coronary disease (P < 0.001), and stable controls (P < 0.001), but not vs. those with unstable angina (P = 0.24). Pooled results from three cohort studies involving 3184 patients evaluating the risk of death following AMI demonstrated that an elevated MPV increased the odds of death as compared with a normal MPV (11.5% vs. 7.1%, odds ratio 1.65, 95% CI 1.12–2.52, P = 0.012). Pooled results from five cohort studies involving 430 patients who underwent coronary angioplasty revealed that MPV was significantly higher in patients who developed restenosis than in those who did not develop restenosis (mean difference 0.98 fL, 95% CI 0.74–1.21, P < 0.001). Conclusions Elevated MPV is associated with AMI, mortality following myocardial infarction, and restenosis following coronary angioplasty. These data suggest that MPV is a potentially useful prognostic biomarker in patients with cardiovascular disease. Whether the relationship is causal, and whether MPV should influence practice or guide therapy, remains unknown.