Coronary Spasm Preferentially Occurs at Branch Points: an angiographic comparison with atherosclerotic plaque

Background —Coronary spasm plays an important role in the pathogenesis of ischemic heart disease. However, similarities and differences between coronary spasm and atherosclerosis are not known. We examined the angiographic characteristics of coro-nary spasm in comparison with those of atherosclerosis. Methods and Results —Thirty two left anterior descending (LAD), 11 left circumflex (LCx) and 23 right coronary arteries (RCA) with spasm and atherosclerotic plaque were analyzed for the localization of spasm in comparison with that of plaque in 47 patients (38 men and 9 women, mean age 66.8±10.3). Spasm predominantly occurred at the branch point as compared with plaque in each of the 3 arteries (76.7 vs. 23.3%, P <0.0001, 72.7 vs. 9.1%, P <0.039, and 60.0 vs. 10.0%, P = 0.002 %, in the LAD, LCx and RCA, respectively). Spasm involved the proximal segment less frequently as com-pared with plaque in each of the 3 arteries (56.7 vs. 93.3%, P <0.0001, 18.2. vs. 81.8%, P = 0.016, and 15.0 vs.75.0%, P <0.0001 in the LAD, LCx and RCA, respectively). The majority of spasm occurred at the non-plaque site in each of the 3 arteries (73.3 %, P =0.018, 100%, P <0.0001, and 75.0 %, P =0.041, in the LAD, LCx and RCA, respectively). Conclusion —Coronary spasm preferentially occurred at branch points and non-plaque sites, whereas the atherosclerotic lesion was predominantly localized at the non-branch points of the curved proximal segments. Coronary spasm may thus be a manifestation of a distinct type of arteriosclerosis different from the lipid-laden coronary atherosclerosis.