Increased Cerebral Artery Atherosclerosis in Korea tion in Asian men aged 35-44 increased from 3.9/100,000 to 10.3/100,000.12 Accumulating evidence of rapidly inc- reasing vascular events in the brain and heart in Koreans as well as Asians suggests that atherosclerotic diseases may also be increasing in this population. Although several studies have investigated cerebral atherosclerosis in Korean and Asian patients with ischemic stroke,3,13-16 information is fragmentary, obtained from a small group of patients, or performed long ago, such that it may not adequately reflect the recent status of Korean and Asian stroke patients. Therefore, the present study investigated the frequency, distribution, and temporal changes in atherosclerosis of the EC and IC cerebral arteries in Korean stroke patients by using stroke registry data obtained consecutively for an eight-year period. MATERIALS AND METHODS Study population We reviewed the records of 2,977 consecutive patients registered in the Yonsei Stroke Registry (YSR) between April 1999 and March 2007. The YSR is a prospective hospital-based registry for patients with an acute cerebral infarction or transient ischemic attack (TIA).17 The study hospital is located in Seoul, which is the capital of Korea. About 69% of patients enrolled for this study were residents of Seoul, and this proportion has not been changed during the study period. The diagnosis requires brain computed tomography (CT) or magnetic resonance imaging (MRI) to exclude hemorrhages and other causes. Systematic investigations were performed in every patient, including 12 lead-electrocardiography, chest X-rays, lipid profiles, and standard blood tests. Additional tests were performed in patients younger than 45 years or in those with no deter- minable etiology. These included measures of serum homocysteine levels and hemostatic markers such as protein C, protein S, antithrombin III, and antiphospholipid antibodies (lupus anticoagulant, anticardiolipin IgG and IgM). Transesophageal echocardiography (TEE) was part of the standard evaluation except in patients with decreased consciousness, poor systemic conditions, tracheal intubation, an inability to accept an esophageal transducer, or lack of informed consent. Transthoracic echocardiography was performed in patients who could not undergo TEE and were suspected of having a cardiac disease. The accuracy and quality of the registry are ensured by reviewing the data of each case at weekly stroke conferences. This study was approved by institutional review board. Risk factors for atherosclerosis The presence of hypertension was defined when patients had resting blood pressure recordings of systolic ≥ 140 mmHg or diastolic ≥ 90 mmHg on repeated measure- ments after clinical stabilization (usually 24-48 hours after admission) during hospitalization or a past medical history for antihypertensive treatment. Diabetes mellitus was diagnosed when a patient had a fasting plasma glucose value ≥ 7 mmol/L or had been treated with an oral hypo- glycemic agent or insulin. Hypercholesterolemia was defined as a fasting serum total cholesterol level ≥ 6.2 mmol/L, LDL-cholesterol > 4.1 mmol/L or a past medical history significant for a lipid-lowering drug. Patients were regarded as smokers if they smoked within the three- month period prior to admission. History of previous stroke included old symptomatic cerebral infarctions and TIAs, which were clinically diagnosed demonstrated with brain imaging studies before admission . Patients enrolled for analysis Among the 2,977 registered patients, 2,779 (91.8%) had an angiography performed [digital subtraction angiography (DSA) in 498 (17.9%), MRA in 1,699 (61.1%), and both DSA and MRA in 582 (20.9%) patients]. MRA was con- ducted using either a 1.5-Tesla system (Signa Horizon, GE Medical System, Milwaukee, WI or Intera or Achieva, Philips Medical System, Best, Netherlands) or a 3.0-T sys- tem (Achieva, Philips Medical System, Best, Netherlands) and almost all patients had underwent contrast enhanced MRA. Echocardiography was performed in 1,508 patients (TEE in 1,192, Transthoracic echocardiography in 182 and both in 134). For the purpose of this study, a total of 1,955 patients were finally enrolled after excluding those who had not undergone an angiographic study, non-Korean, those with potential cardiac sources of embolism (PCSE) or other determined etiologies, such as arterial dissection, Moyamoya disease, coagulation disorders, etc., and those who had been treated with stent insertion/angioplasty or carotid endarterectomy before the admission at our hospital. In patients with both DSA and MRA performed, the results of DSA were used for analysis, and in patients with MRA studies performed at different times due to re-admission or recurrent attacks, the most recent results were used for analysis. Therefore, data of only one angiographic study from each patient was used. Finally, data from 725 DSA (37.1%) and 1,230 MRA (62.9%) were analyzed for this study (Fig. 1). Definition of atherosclerosis and degree of stenosis Any abnormalities on angiographic studies were deter- mined at a weekly stroke conference based on a neurora- diologist’s report and the consensus of stroke specialists. Angiographic findings were defined as normal, stenotic, or occluded in each arterial segment and branch arteries of Yonsei Med J http://www.eymj.org Volume 51 Number 3 May 2010 319