Coronary plaque burden of the left anterior descending artery in patients with or without myocardial bridge: A case-control study based on coronary CT-angiography

Abstract

Background: The clinical significance of myocardial bridging (MB) on the left anterior descending artery (LAD) is debated. We aimed to assess the association between MB and LAD plaque volumes/compositions in a case-control set up.

Methods: In our retrospective analysis we investigated 50 cases with incidentally recognized LAD MB and 50 matched controls without LAD MB on coronary computed tomography angiography. We quantified plaque volumes proximal to the MB and beneath it in patients with MB and in the corresponding coronary segments in patients without MB.

Results: In total, we have included 100 patients (mean age 60.6 ± 10.8 years, males: 80%). Plaque volume was similar in the LAD segments proximal to the MB in cases vs. controls (150.0 mm³ [IQR: 90.7-194.5 mm³] vs. 132.8 mm³ [IQR: 94.2-184.3 mm³], respectively; p = 0.95) while the plaque volume was smaller beneath LAD MB vs. control segment (16.2 mm³ [IQR: 12.6-25.8 mm³] vs. 21.1 mm³ [IQR: 14.0-42.4 mm³], respectively; p = 0.002). No significant differences were found regarding different plaque components in segments proximal to the MB while fatty plaque and necrotic core volumes were smaller or negligible in coronary segment beneath MB than in controls (0.07 mm³ [IQR: 0.005-0.27 mm³] vs. 12.7 mm³ [IQR: 7.4-24.4 mm³] and 0.00 mm³ [IQR: 0.00-0.04 mm³] vs. 0.06 mm³ [IQR: 0.03-2.8 mm³], respectively (p < 0.001).

Conclusion: Comparing patients with MB vs. matched controls without it, MB was not associated with increased plaque volumes in LAD segment proximal to MB and plaque quantity was smaller in the MB segment. Our data are supportive of benign nature of incidentally recognized LAD MB.

Keywords: Coronary computed tomography angiography; Coronary plaque composition; Coronary plaque volume; Myocardial bridge; Plaque quantification.