Correlation between left main coronary artery bifurcation angle and non-calcified plaque and its hydrodynamics

Abstract

Objective To investigate the correlation between the angle and distribution of non-calcified plaque of left main coronary bifurcation and its hydrodynamic theory. Methods Retrospective analysis of 55 patients suspected of coronary heart disease who had undergone coronary computed tomographic angiography from January 2014 to June 2016. Angle, quadrant distribution, distance from bifurcation reference plane, minimal lumen area and extravascular elastic membrane cross section area of left main coronary bifurcation were measured. Then we calculated the plaque burden. The left main coronary bifurcation lesions were divided into plaque group and non-plaque group. Student's t test was used to compare the two groups.The left main coronary bifurcation lesions were divided into ≥70° group and<70° group, Chi-square test and Fisher exact test were used to compared the two groups. Pearson correlation analysis was used to analyse the bifurcation angle and plaque distance. The data of non-plaque group was imported into the MIMICS,3-MATIC and abaqus CFD software to establish the hydrodynamic model, which was used to analyze the changes of pressure and velocity at different angles. Results Plaque group has 25 patients whose average value of the bifurcation angle was (55.95±14.77)°;non-plaque group has 30 patients whose average value of the bifurcation angle was(55.95±14.77)°.Angle difference was statistically significant between plaque and non-plaque group(t=2.893, P=0.006);Plaque difference was statistically significant between ≥70° and<70° groups. The distance was negatively correlated with bifurcation angle(r=-0.773, P<0.001). Following the increase of bifurcation angle, the vascular wall area of high pressure and low speed region growed The green region of low-wall pressure with irregular distribution appeared in the lateral wall of the vessel that opposite to the red region of the bifurcation, and this region had lager gradient variability of wall pressure. Conclusion With the increase of coronary bifurcation angle, the possibility of plaque formation increases, the distance from plaque to bifurcation increases,the plaques tend to appear in the lateral wall of the blood vessels. Key words: Coronary vessels; Tomography, X-ray computed; Hydrodynamic