Epidemiology, Pathophysiology, and Medical Management of Intracranial Atherosclerotic Disease

Intracranial atherosclerotic disease (ICAD) is a condition in which atherosclerosis causes narrowing or blockage of intracranial blood vessels. ICAD is recognized as a leading cause of ischemic stroke worldwide. While ICAD-related stroke/transient ischemic attack (TIA) appears more frequently in Asia, the conditions of studies reporting on the prevalence of ICAD vary between studies. However, differences in the prevalence of ICAD do exist between ethnic groups. On the other hand, the prevalence of asymptomatic ICAD in the general population shows no apparent tendency across countries or regions. ICAD is thought to have a slightly different pathological basis than atherosclerotic disease involving coronary or extracranial arteries. Several mechanisms for ischemic stroke due to ICAD have been proposed. The annual recurrence rate of stroke is almost 10%–15% in symptomatic ICAD, compared to around 1% in asymptomatic ICAD. Dual antiplatelet therapy (DAPT) with aspirin and P2Y12 receptor inhibitors appears reasonable as antithrombotic treatment in patients with acute stroke or TIA due to ICAD, while DAPT combining aspirin or clopidogrel with cilostazol can be considered for long-term treatment. The best medical management also involves blood pressure control targeting <140/90 mmHg and aggressive lowering of lipid levels with statins.