[Marked decrease of intracranial atherosclerosis in contrast with unchanged coronary artery stenosis in Japan]

Area of Science:

• Cardiovascular Research
• Neuropathology
• Epidemiology

Background:

• Atherosclerosis affects both intracranial and coronary arteries, posing significant health risks.
• Long-term trends in the prevalence of intracranial atherosclerosis compared to coronary artery stenosis are not well-documented.

Purpose of the Study:

• To comparatively analyze the trends of intracranial atherosclerosis and coronary artery stenosis over a 28-year period.
• To identify risk factors associated with intracranial atherosclerotic changes in an elderly Japanese population.

Main Methods:

• Autopsy case studies from 1974-1975, 1986-1987, and 2000-2001 involving 1261 elderly subjects.
• Semi-quantitative evaluation of atherosclerotic changes in the middle cerebral and basilar arteries to derive an Intracranial Atherosclerotic Index (ICAI).
• Calculation of Coronary Stenotic Index (CSI) and analysis of risk factors including blood pressure, total cholesterol, and diabetes mellitus.

Main Results:

• A dramatic chronological decrease in ICAI was observed, contrasting with unchanged CSI.
• Blood pressure showed a significant positive correlation with both ICAI and CSI.
• Diabetes mellitus correlated positively with CSI and ICAI, while total cholesterol correlated with CSI but not ICAI.

Conclusions:

• This study provides the first morphological evidence of a marked decrease in intracranial atherosclerosis in Japanese elderly subjects over the past 28 years.
• Coronary artery stenosis showed no significant change during the same period.
• Age and blood pressure were identified as major risk factors for intracranial atherosclerosis.