Objectives: The aim of this study was to identify predictors of significant LCx-ostium compromise after distal unprotected left main coronary artery (ULMCA) stenting on the basis of baseline intravascular ultrasound (IVUS).
Background: Provisional single-stenting is considered as the default strategy for non-true bifurcation lesions in ULMCA. However, in certain cases, left circumflex artery (LCx)-ostium stenting is necessary.
Methods: A total of 77 patients underwent percutaneous coronary intervention with drug-eluting stents for non-true bifurcation lesions in ULMCA and had IVUS evaluation. Pre-procedural IVUS was performed to measure cross-sectional areas at the following segments: left main trunk, left anterior descending artery (LAD)-ostium. Post-stenting-narrowing at the circumflex ostium (PSN-LCx) was defined as the presence of more than 50% diameter stenosis at the LCx-ostium as determined by quantitative coronary angiography analysis.
Results: PSN-LCx occurred in 27 (35%) patients. The presence of calcified plaque at the culprit lesion as identified by IVUS was more frequently observed in the PSN-LCx group as compared to the non-PSN-LCx group (81.5% vs. 22.0%, p<0.001). Calcium arc in the PSN-LCx group was significantly greater than that in the non-PSN-LCx group (118.1°±69.9° vs. 36.9°±63.0°, p<0.001). On multivariable analysis, a calcium arc>60° was an independent predictor of PSN-LCx (odds ratio: 5.12, 95% confidence interval: 1.21-25.01, p=0.03).
Conclusions: The presence of calcified plaque at the culprit lesion appears to be one of the factors involved in LCx-ostial compromise in non-true bifurcation ULMCA lesions, especially when the calcium arc is >60°.
Keywords: Bifurcation; Intravascular ultrasound; Left main coronary artery stenosis; Plaque morphology.
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