Low level of high-density lipoprotein (HDL) cholesterol predictive of outcome after cardiac stenting

HDL Forum Editor Professor John Chapman comments on evidence that a low level of high-density lipoprotein (HDL) cholesterol is an independent predictor of long-term outcome after cardiac stenting. The study was published in Thrombosis and Haemostasis.

Niessner A, Hofmann R, Kypta A et al. Low high-density lipoprotein cholesterol predicts cardiovascular events after carotid stenting: a long-term survey. Thromb Haemost 2007;5:950-4.

In this study, 532 patients assigned for carotid artery stenting were followed-up over a median of 28 months (interquartile range 15-49 months). The primary endpoint over this period was a composite of stroke, myocardial infarction and all-cause mortality.

Cumulative event rates for the primary endpoint were 4.4%, 17.1% and 33.4% over 1,3 and 5 years. HDL cholesterol was shown to be an independent predictor of event-free survival; the adjusted Hazard ratio for the primary endpoint was 0.97 (95%CI 0.95-0.99, p=0.002) per 1 mg/dL increase in HDL cholesterol. Low HDL cholesterol (<40 mg/dL in men and <50 mg/dL in women) was associated with an increased risk of a primary endpoint; the adjusted Hazard ratio for the primary endpoint was 2.7 (95%CI 1.6-4.4, p<0.001).

In addition, patients with both low HDL cholesterol and elevated levels of inflammatory markers (leukocyte count > 10,000/ml, fibrinogen > 450 mg/dL or erythrocyte sedimentation rate > 20 mm/h) were at very high risk, with a 5-year event rate of 59.4% (95%CI 43.6-75.2%) compared with 15.1% (95%CI 8.2%-22.0%) in patients with neither risk factor.

These important and original data not only identify the level of HDL cholesterol as an independent predictor of long term cardiovascular outcome after carotid stenting, but equally reveal that association of an inflammatory state with low HDL cholesterol levels is a key feature of patients at very high cardiovascular risk post-stent. Raising HDL cholesterol is therefore a primary therapeutic target for attenuation of cardiovascular events after carotid artery stenting. Future prospective intervention studies with new HDL raising agents should clearly be targeted at this major patient group