Effects of cigarette smoking on intramyocardial arteries and arterioles in man.

Proliferative lesions, which include collagen, elastic fibers and abnormally oriented muscle fibers, were found to develop in intramyocardial arteries more rapidly with age in cigarette smokers than in nonsmokers. The study attempted to determine whether these lesions reduce perfusion pressures in the subendocardial zone of the left ventricle. The amount of muscle in arterioles appears to reflect perfusing pressures, so measurements were made of decreases in muscle in arterioles between the subepicardial and subendocardial zones of the left ventricle to detect decreases in arteriolar perfusing pressures between the two areas. The decreases in arteriolar muscle between the two zones were then compared with the extents of the intramyocardial arterial lesions. Those individuals who had the most extensive arterial proliferative lesions had the greatest decreases in arteriolar muscle from the subepicardial to the subendocardial zones. In persons less than 60 years old the mean decreases in arteriolar muscle between the two zones were 1% for nonsmokers and 17% for smokers. For those more than 60 years old the values were 21 and 41%.