Clinical usefulness of the angle between left main coronary artery and left anterior descending coronary artery for the evaluation of obstructive coronary artery disease

BACKGROUND: A wider angle between the left anterior descending coronary artery (LAD) and left circumflex coronary artery (LCX) has been suggested to induce plaque formation in the arterial system via changes in shear stress. However, the relationship between the left main coronary artery (LM)-LAD angle and LAD stenosis has not been investigated. Therefore, we aimed to evaluate the associations between the LM-LAD and LAD-LCX angles and LAD stenosis. METHODS: Coronary computed tomography angiographies (CTAs) of 201 patients with suspected coronary artery disease were analyzed. Angle measurements were performed twice by experts using CTA images, and the values were averaged. The patients were divided into two groups, based on the presence of significant LAD stenosis (luminal diameter narrowing ≥50%) on CTA. RESULTS: The mean LM-LAD and LAD-LCX angles were 37.46° and 63.04°, respectively. The LM-LAD and LAD-LCX angles of the group with significant LAD stenosis were significantly wider than that of the group with nonsignificant LAD stenosis (P<0.001; P = 0.020, respectively). In a multivariate analysis, an LAD-LCX angle greater than 60° showed a trend toward predicting significant LAD stenosis (HR, 3.14; 95% CI: 0.96–1026; P = 0.058). In contrast, an LM-LAD angle greater than 40° was a significant predictor of significant LAD stenosis (HR, 12.2; 95% CI: 2.60–56.52; P = 0.001). CONCLUSIONS: The results of the present study may suggest that a wider LM-LAD angle could be used to identify patients at higher risk for coronary artery disease (CAD). Thus, close follow–up and preventive management of other risk factors may be needed in such cases.