Geographical predisposition influences on the distribution and tissue characterisation of eccentric coronary plaques in non-branching coronary arteries: cross-sectional study of coronary plaques analysed by intravascular ultrasound

BACKGROUND: We investigated the influence of geographical predisposition on the spatial distribution and composition of coronary plaques. METHODS: Thirty coronary arteries were evaluated. A total of 1441 cross-sections were collected from intravascular ultrasound (IVUS) and radio-frequency signal-based virtual histology (VH-IVUS) imaging. To exclude complex geographical effects of side branches and to localise the plaque distribution, we analysed only eccentric plaques in non-branching regions. The spatial distribution of eccentric plaques in the coronary artery was classified into myocardial, lateral, and epicardial regions. The composition of eccentric plaques was analysed using VH-IVUS. RESULTS: The plaque was concentric in 723 sections (50.2%) and eccentric in 718 (49.9%). Eccentric plaques were more frequently distributed towards the myocardial side than towards the epicardial side (46.7 ± 7.5% vs. 12.5 ± 4.2%, p = 0.003). No significant difference was observed between the myocardial and lateral sides (46.7 ± 7.5% vs. 20.8 ± 5.0%) or between the lateral and epicardial sides. Eccentric thin-capped fibroatheromas were more frequently distributed towards the myocardial side than towards the lateral side (p = 0.024) or epicardial side (p = 0.005). CONCLUSION: Geographical predisposition is associated with distribution, tissue characterisation, and vulnerability of plaques in non-branching coronary arteries.