Interaction of Extracranial and Intracranial Vascular Stenosis: Etiologic, Diagnostic, and Prognostic Study

• Main Authors: Sung Yueh-Feng, 宋岳峰
• Other Authors: Peng Giia-Sheun
• Format: Others
• Language: en_US
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/93156800426761921010

博士 === 國防醫學院 === 醫學科學研究所 === 104 === Stroke is the third leading cause of death and one of the main causes of disability in the elderly population in Taiwan. Stroke includes ischemic and hemorrhagic stroke. In Taiwan, approximately 70-80% of cases of stroke are ischemic. Extracranial high-grade carotid stenosis (ECS) is a well-known risk factor for ischemic stroke. The risk of stroke increases if the patient has concomitant intracranial stenosis (ICS). Previous studies have demonstrated that ECS often accompanies reversed ophthalmic artery flow (ROAF); however, the role of ROAF in acute stroke patients with unilateral ECS remains poorly understood. ICS is more common in Asians compared with Caucasians. While several vascular risk factors have been identified, these have varied among studies. Moreover, certain genes may play an important role in determining the locations of cervicocerebral stenosis. Previous studies have shown significant variation in ALDH2 gene polymorphism in different races. Furthermore, ALDH2*2 mutant has been linked to diabetes mellitus (DM), coronary artery disease (CAD) and hyperlipidemia. However, the association between ALDH2 gene polymorphism and stroke or ECS/ICS remained unknown. The objective of this thesis was to investigate the interaction of extracranial and intracranial vascular stenosis in Taiwanese patients, from etiologic, diagnostic, and prognostic aspects. First, among the subjects with unilateral ECS, the acute stroke group had significantly higher percentages of ROAF and ICS. ICS is a major stroke risk indicator as well as a predictor for worse stroke outcomes. ROAF may provide partial compensation for improving stroke outcomes. In a secondary experiment, we compared the prevalence of ischemic stroke and risk factors in varied distributions of cervicocerebral stenosis. Prevalence of ischemic stroke was highest in patients with combined ECS/ICS (CEIS), followed in decreasing order by those with isolated ICS (IICS), isolated ECS (IECS), and non-ECS/ICS. Smoking, DM, and CAD were the greatest contributors to CEIS, IICS, and IECS, respectively. In a third experiment, we found that ALDH2 gene polymorphism was not correlated with vascular risk factors, ECS, ICS, stroke subtypes, and stroke outcomes in patients with acute ischemic stroke. However, ALDH2*2/*2 is an independent risk factor for ischemic stroke in male patients. In conclusion, ROAF may provide partial compensation for improving outcomes in acute ischemic stroke patients with unilateral ECS. Smoking, DM, and CAD were the major determinants of CEIS, IICS, and IECS respectively. ALDH2 gene polymorphism was not correlated with vascular risk factors, ECS, ICS, stroke subtypes, and stroke outcomes in male patients with ischemic stroke. However, ALDH2*2/*2 genotype was an independent risk factor for ischemic stroke in Taiwanese male patients. Our findings may help to elucidate the pathomechanism of cervicocerebral stenosis, and facilitate a strategy to reduce the risk and accelerate the development of multidisciplinary treatments for ischemic stroke.