Intracranial Artery Stenosis and Its Association With Conventional Risk Factors in a General Population of Japanese Men

Abstract

Background and Purpose— Few community-based studies have reported the prevalence of intracranial artery stenosis (ICAS) assessed with magnetic resonance angiography. The aim was to determine the prevalence of ICAS using magnetic resonance angiography in a general population of Japanese men and to investigate the associations between ICAS and conventional cardiovascular risk factors. Methods— The Shiga Epidemiological Study of Subclinical Atherosclerosis randomly recruited and examined participants from Kusatsu City, Shiga, Japan, in 2006 to 2008 (baseline); 740 men returned for follow-up and underwent 1.5 T brain magnetic resonance angiography in 2012 to 2015. Participants were categorized as having no-ICAS, mild-ICAS (1 to <50%), or severe-ICAS (≥50%) in any of the arteries examined. After excluding the men with a history of stroke, 709 men were analyzed using multivariable logistic regression to assess independent associations of conventional cardiovascular risk factors with reference to the no-ICAS group. Results— The participants’ mean age was 68.0 years. The age-standardized prevalences of mild and severe-ICAS were 20.7% and 4.5%, respectively (with the population of the 2010 Japanese vital statistics as the reference). Age, hypertension, diabetes mellitus, and dyslipidemia were associated with a higher prevalence of severe-ICAS after simultaneous adjustment for conventional cardiovascular risk factors. Conclusions— In a community-based sample of Japanese men, ICAS was estimated to be present in 25.2%, and related to metabolic risk factors, in addition to hypertension and age. These results support the importance of comprehensive management of conventional cardiovascular risk factors for stroke prevention.

The Association Between Coronary Artery Calcification and Subclinical Cerebrovascular Diseases in Men: An Observational Study

“…This was an observational study that included men who participated in the Shiga Epidemiological Study of Subclinical Atherosclerosis (SESSA). The enrollment methods have been reported previously 9 , 11 ) . In brief, from May 2006 to March 2008, 2,379 Japanese men aged 40–79 were randomly selected and invited on the basis of the residents' registry of Kusatsu, Shiga Prefecture, Japan.…”

“…Two neurosurgeons (KN, AS), certified by the Japan Neurosurgical Society, independently assessed all MRI/MRA images in duplicate without knowledge of the participants' characteristics. Disagreement in assessment was resolved with adjudication by the neurosurgeons 9 ) .…”

“…We evaluated 11 intracranial arteries for stenosis. These included the basilar artery plus the following five vessels bilaterally: intracranial segments of the internal carotid artery, the middle cerebral artery, the anterior cerebral artery, intracranial segments of the vertebral artery, and the posterior cerebral artery 9 ) . For each artery, the degree of narrowing was graded using criteria established in the Warfarin-Aspirin Symptomatic Intracranial Disease trial 16 ) as follows: no detectable stenosis, 1–49% stenosis, 50–99% stenosis, and complete occlusion (100%).…”

“…We categorized the participants into three groups according to the CAC score as follows: 0 (no CAC), 1–100 (mild CAC), and > 100 (moderate-to-severe CAC). We dichotomized each of the four small-vessel diseases and ICAS as follows: lacunar infarction (defined as number of lesions ≥ 1), DSWMH (grade ≥ 3) 20 ) , PVH (grade ≥ 2) 20 ) , microbleeds (defined as number of lesions ≥ 1), and presence of ICAS (defined as stenosis of ≥ 1% identified in any of the arteries assessed) 9 ) .…”

“…Magnetic resonance imaging (MRI), as compared to transcranial Doppler, is a suitable method for assessing SCVDs in a community-based sample given its noninvasive nature and its superiority in assessing intracranial arterial stenosis (ICAS) 9 ) . In MRI of the brain, cerebral small-vessel diseases often manifest as lacunar infarction, white matter lesions, and microbleeds 7 ) , whereas large-vessel diseases, such as ICAS, are detected as stenotic lesions of major cerebral arteries 10 ) .…”