Advantages of Lipid-Lowering Therapy in Cerebral Ischemia: Role of HMG-CoA Reductase Inhibitors

Abstract

Dyslipemia as a risk factor for ischemic stroke and indications for statins in the prevention of ischemic stroke are revised. The role of cholesterol levels as a risk factor for ischemic stroke is controversial. This could be due to failures in the design of early epidemiological studies. Recent studies, however, do suggest a clearer risk relationship between cholesterol levels and ischemic stroke. Studies conducted on the prevention of ischemic heart disease (IHD) with 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins), using pravastatin and simvastatin, unequivocally show reductions in overall mortality, cardiovascular mortality, acute myocardial infarction and other coronary events. These studies show a reduction in the risk of ischemic stroke, and although relative risk reduction is great, absolute risk reduction is low; the reasons for this are analyzed. Apart from lipid mechanisms, statins act on the atheroma plaque; they have antithrombotic and possibly neuroprotecting properties. Statins reduce the number of strokes due to the decrease of atherothrombotic strokes, cardioembolic strokes secondary to IHD, and lacunar strokes related to atherothrombosis and probably to microatheromas. Although there are currently no specific studies available on the secondary prevention of stroke with statins, which are required to clarify certain points, according to European and American guidelines for prevention, statins would be indicated in the secondary prevention of atherothrombotic stroke, and in cardioembolic and lacunar stroke associated with clinical or silent atherosclerosis (IHD, peripheral artery disease). Patients with ischemic stroke of other etiologies, except for stroke in the young or other unusual causes, are patients with a high vascular risk (cardiac and cerebral) owing to the stroke itself, age and other vascular risk factors, and they should also be treated with statins, at least from the point of view of primary prevention of IHD. Natural statins (pravastatin and simvastatin) play an essential part in secondary prevention of ischemic stroke, together with antiaggregants, anticoagulants, angiotensin-converting enzyme inhibitors and the treatment of other vascular risk factors.