Abstract
The role of atherosclerosis in coronary artery spasm was studied by morphometrical examinations of isolated postmortem human coronary arteries that were used for the observation of spontaneous periodic contractions. Isometric tension of coronary ring segments from seventy-six cadavers was recorded in a bath containing physiological saline solution. According to the degree of atherosclerosis, the segments were classified into three groups: minimum intimal lesion (Group I), moderate intimal lesion (Group II) and severe atherosclerotic lesion (Group III). Results were analyzed by a chi-square test. The incidence of the spontaneous periodic contractions was 45% in the proximal portion. Of the segments in which the contractions occurred, 83% were in Group Ii. There were significant differences in the incidence between Group I and II (33% vs 80%; p<0.02) and Group II and III (80% vs 25%, p<0.001), respectively. According to the characteristics of the atherosclerosis, there were significant differences in incidence of the contractions between circumferential thickening and eccentric thickening in Group II (63% vs 28%; p<0.001). In conclusion, the spontaneous periodic contractions occur most frequently in the segments in which (1) the degree of atherosclerosis is moderate rather than minimum or severe and )2) the characteristics of atherosclerosis is circumferential thickening instead of eccentric thickening.
