Quantitative angiography and optical coherence tomography for the functional assessment of nonobstructive coronary stenoses: Comparison with fractional flow reserve

BackgroundThe purpose was to compare 3-dimensional quantitative coronary angiography (3D-QCA) with optical coherence tomography (OCT) for the functional assessment of nonobstructive coronary stenoses, as evaluated by fractional flow reserve (FFR).MethodsFifty-five nonobstructive coronary stenoses (30%-50% diameter stenosis by visual estimation) were assessed in 36 patients using FFR, 2-dimensional QCA (2D-QCA), 3D-QCA, and OCT.ResultsAngiographic stenosis severity by 2D-QCA was 34% ± 13% diameter stenosis, and minimal lumen diameter (MLD) was 1.77 ± 0.58 mm. Fractional flow reserve values were 0.85 ± 0.10. Correlation coefficients between FFR and MLD or minimal lumen area (MLA) were highly significant for both 2D- and 3D-QCA (all P < .001), but higher R2 values were observed for 3D-QCA measurements. Although significant, correlation coefficients between OCT and FFR data were weak (R2 = 0.28, P = .001 for MLD and R2 = 0.23, P = .003 for MLA). Correlation coefficients with FFR were significantly higher for 3D-QCA than for OCT (P values for MLD and MLA = .043 and .042, respectively). Nonobstructive stenoses with MLD > 1.53 mm or MLA > 2.43 mm2 are unlikely to be hemodynamically significant.ConclusionsIn nonobstructive coronary stenoses, anatomical parameters derived from 3D-QCA can best identify lesions with preserved FFR values.