Intracranial Atherosclerosis in Stroke Patients - Prevalence, Risk Factors, and Impact on Survival: A Retrospective Study from a Mixed Ethnic Population in Singapore

Introduction: Intracranial atherosclerosis (ICAD), although more common in Asians, has not been studied in a Singapore population. Objective: The aim of this study is to identify the prevalence of ICAD in stroke subjects, its association with comorbidities, stroke subtypes, and long-term survival. Materials and Methods: We performed retrospective analysis of 681 stroke patients and performed multivariable analysis to identify the prevalence of ICAD and associated risk factors. Results: 327 (48%) had ICAD with 232 (71%) having one or more intracranial arteries with significant stenosis. ICAD was associated with older age, ischemic strokes, total anterior circulation syndrome, large artery strokes ( P < 0.001), peripheral vascular disease ( P = 0.018), diabetes mellitus (DM), and with a history of hyperlipidemia. In addition, higher serum potassium ( P = 0.046) and glucose ( P < 0.001), lower hemoglobin ( P = 0.040) and aortic valve sclerosis were significantly associated with ICAD ( P < 0.001). Multivariable analysis showed a significant independent association of ICAD with advancing age, history of hyperlipidemia, and DM. In ischemic strokes (489), 311 (64%) had ICAD, of which 229 (72%) had significant stenosis. Of the 192 hemorrhagic strokes, 16 (8%) had ICAD. Conclusion: The prevalence of ICAD, especially in ischemic strokes, from our study is high. As modifiable risk factors such as hyperlipidemia and DM appear to be associated with ICAD, then proactive management of these conditions may improve long-term associated complications. Prospective studies may help to validate our findings.