A novel method to assess coronary artery bifurcations by OCT: cut-plane analysis for side-branch ostial assessment from a main-vessel pullback

Aims In coronary bifurcations assessment, evaluation of side-branch (SB) ostia by an optical coherence tomography (OCT) pullback performed in the main branch (MB) could speed up lesion evaluation and minimize contrast volume. Dedicated software that reconstructs the cross-sections perpendicular to the SB centreline could improve this assessment. We aimed to validate a new method for assessing the SB ostium from an OCT pullback performed in the MB. Methods and results Thirty-one sets of frequency-domain OCT pullbacks from 28 patients, both from the MB and the SB of a coronary artery bifurcation were analysed. Measurements of the SB ostium from the SB pullback were used as a reference. Measurements of the SB ostium from the MB pullback were then performed in a laboratory setting by (i) conventional analysis and (ii) cut-plane analysis, and the measurement error for each analysis was estimated. Correlations of SB ostium measurements acquired from the MB pullback in comparison with reference measurements acquired from the SB pullback were higher with cut-plane analysis compared with conventional analysis, albeit not reaching statistical significance (area: r(cut-plane) = 0.927 vs. r(conventional) = 0.870, P = 0.256; mean diameter: r(cut-plane) = 0.918 vs. r(conventional) = 0.788, P = 0.056; minimum diameter: r(cut-plane) = 0.841 vs. r(conventional) = 0.812, P = 0.734; maximum diameter: r(cut-plane) = 0.770 vs. r(conventional) = 0.635, P = 0.316). Cut-plane analysis was associated with lower absolute error than conventional analysis (area: 0.56 +/- 0.45, vs. 1.50 +/- 1.31 mm(2), P < 0.001; mean diameter: 0.18 +/- 0.14 vs. 0.44 +/- 0.30 mm, P < 0.001). Conclusion Measurements of SB ostium performed in a laboratory setting by cut-plane analysis of an OCT pullback of the main branch have high correlation with reference measurements performed in a SB OCT pullback and lower error compared with conventional analysis.