Background: Atherosclerotic stenosis of large IC arteries is an important cause of stroke. The prevalence of ICS in stroke population differs by ethnicity.We report the frequency of ICS among a global sample of patients with non-lacunar cryptogenic ischemic stroke (NLCIS) who did not have another identifiable cause for stroke i.e. cardioembolic, extracranial LAD, or other specific causes.
Hypothesis: We hypothesized that the prevalence rates of ICS will differ according to global regions.
Methods: Consecutive patients with recent ischemic stroke were retrospectively surveyed at 19 stroke centers in 19 countries to identify the frequency of IC imaging and its yield. Countries were grouped by World Bank regions. ICS was considered to be significant if there was >50% stenosis in the arteries proximal to the index stroke evidenced by MRA, CTA or TCD.
Results: We identified a total of 2145 consecutive ischemic stroke patients among which 475 had NLCIS. IC arterial imaging was carried-out,on average, in 87% of patients. Of these 414 patients, 15% had stenosis proximal to the area of brain ischemia. The frequency of ICS among NLCIS patients was highest in East Asia (27%) and lowest in Pacific (4%). Patients with ICS in Latin America were significantly younger when compared to other 4 regions.
Conclusion: IC arterial imaging is carried out in majority of stroke centers in patients with NLCIS, among whom the fraction of IS associated with ICS is substantial throughout the world, averaging about 15%. MRA / CTA had a higher yield than TCD. On average these patients have traditional vascular risk factors except for Latin American patients who are significantly younger with no vascular risk factors.