Abstract: Abstract: Objective To preliminary investigate the relationship between right coronary artery (RCA) origin-aortic angle, RCA plaque composition and coronary artery stenosis by coronary CT angiography (CCTA). Methods A total of 631 consecutive patients undergoing CCTA examination in our hospital were retrospectively analyzed. According to the presence or absence of RCA plaques, patients were divided into normal group (n=279) and plaque group (n=352). The plaque group was further divided into calcified group (n=72), non-calcified group (n=181) and mixed plaque group (n=99) based on the different CT values of different plaque components. According to the presence or absence of RCA stenosis, the patients were divided into non-stenosis group (n=383) and stenosis group (n=248). The stenosis group was further divided into ＜50% stenosis group and ≥50% stenosis group. The differences of the RCA origin-aortic angle were compared between normal group and plaque groups, and between no stenosis group and stenosis groups. Results In the normal group, the angle of the RCA origin-aorta was significantly larger in males than that of females (P＜0.05). The RCA origin-aortic angles of noncalcified plaque group and mixed plaque group were both smaller than that of normal group (P＜0.05). There were no significant differences in RCA origin-aortic angles between calcified plaque group and the other groups. Compared with nonstenosis group, the angles of RCA origin-aorta were reduced in both the ＜50% stenosis group and ≥50% stenosis group (P＜ 0.05). There was no statistically significant difference in the RCA origin-aortic angle between the ＜50% stenosis group and ≥50% stenosis group. Conclusion Non-calcified and mixed plaques are prone to form when the angle between the RCA origin and the aorta is smaller. If the plain CT scan shows that the angle is smaller, it indicates that plaque and stenosis may exist in the RCA.

Key words: coronary stenosis, plaque, atherosclerotic, right coronary artery, coronary computed tomography
angiography, right coronary artery origin-aortic angle