Role of Blood Lipid Levels and Lipid-Lowering Therapy in Stroke Patients with Different Levels of Cerebral Artery Diseases: Reconsidering Recent Stroke Guidelines

Hyperlipidemia is an important risk factor for ischemic stroke; the Stroke Prevention by Aggressive Reduction in Cholesterol Level and Treat Stroke to Target studies have shown that statins are beneficial for patients with stroke and that a low target for low-density lipoprotein cholesterol (LDL-C) concentration may maximize this benefit. Based on these results, recent guidelines have emphasized the application of “high-intensity statins” and “low LDL-C target” strategies in patients with stroke. However, it should be kept in mind that the role of blood lipids as a risk factor and benefit of lipid-lowering therapy are different among patients with different levels of cerebral arterial diseases. Studies have suggested that hypolipidemia, but not hyperlipidemia, is a risk factor for small vessel diseases (SVDs) such as intracerebral hemorrhages, microbleeds, white matter hyperintensities, and perhaps, lacunar infarction. Although lipid-lowering agents might benefit certain patients with SVD, high-intensity statin and low LDL-C target strategies cannot be applied. In contrast, these strategies are important in patients with extracranial atherosclerosis, such as internal carotid disease, considering ample evidence of the benefits of lipid-lowering agents. Imaging studies have shown that statins stabilize vulnerable plaques in these patients. Although lipid-lowering agents are likely to benefit patients with intracranial atherosclerosis, the degree of their benefit and appropriate target LDL-C level for these patients remain unclear. More studies are needed to elucidate the appropriate lipid-modifying strategies in patients with stroke with different levels of cerebral artery disease.