Dyslipidemia as a risk factor for ischemic stroke.

Ischemic stroke is a major cause of morbidity and mortality. Whereas dyslipidemia is a major risk factor for coronary heart disease (CHD), its role in the pathogenesis of ischemic stroke is less clear. Epidemiological studies have provided conflicting findings regarding the association of dyslipidemia with ischemic stroke. Overall, elevated LDL-C levels appear to increase the risk of ischemic stroke. Low HDL-C levels also appear to be associated with a greater risk whereas the importance of high triglyceride levels is less clear. The discordant results of observational studies might result from the heterogeneity of stroke, since dyslipidemia is less likely to play a major role in the pathogenesis of some ischemic stroke subtypes (e.g. lacunar and cardioembolic strokes) and elevated LDL-C levels might increase the risk of hemorrhagic stroke. In clinical trials, statins consistently reduced the risk of ischemic stroke in patients with or without CHD whereas the data on the effects of other lipid modifying drugs on stroke risk are limited. In patients with a previous stroke, statins reduce the risk of both ischemic stroke and other vascular events but also increase the risk of hemorrhagic stroke. Accordingly, current guidelines recommend the same lipid targets for the primary and secondary prevention of both stroke and CHD. In addition, stroke and transient ischemic attacks of carotid origin are considered CHD risk equivalents. Nevertheless, more trials are required to identify which patients with stroke but without CHD will benefit more from statin treatment.