Evaluation of hemodynamically severe coronary stenosis as determined by fractional flow reserve with frequency domain optical coherence tomography measured anatomical parameters

ObjectivesThe main objective of this study is to determine the correlation between fractional flow reserve (FFR)- and frequency domain optical coherence tomography (FD-OCT)-measured lumen parameters, and to determine the diagnostic competence of FD-OCT concerning the identification of severe coronary stenosis.MethodsA total of 41 coronary stenoses in 30 patients were assessed consecutively by quantitative coronary angiography (QCA), FFR, and FD-OCT. Stenoses were labeled severe if FFR ≤ 0.80. The minimal lumen area (MLA), minimal lumen diameter (MLD), and percent lumen area stenosis (%AS) were measured using FD-OCT.ResultsFFR was ≤0.80 in 10 stenoses (24.4%). A poor but significant correlation between FFR and FD-OCT-measured MLA (r2 = 0.4, p < 0.001), MLD (r2 = 0.28, p < 0.001), and %AS (r2 = 0.13, p = 0.02) was found. In the overall group, the diagnostic efficiency of MLA and MLD in identifying significant stenosis was moderate. The area under the curve (AUC) was 0.80 [95% confidence interval (CI): 0.64–0.91] for MLA and 0.76 (95% CI: 0.60–0.88) for MLD. The best cut-off values of FD-OCT-measured lumen parameters to identify stenosis with FFR ≤ 0.80 were 1.62 mm2 [specificity 97%, sensitivity 70%, positive predictive value (PPV) 89% and negative predictive value (NPV) 91%] for MLA and 1.23 mm (specificity 87%, sensitivity 70%, PPV 64% and NPV 90%) for MLD. The diagnostic efficiency of MLA in identifying significant stenosis in vessels having reference diameter < 3 mm was high. The AUC was 0.96 (95% CI: 0.83–1.0).ConclusionsThe FFR values and FD-OCT anatomical parameters MLA, MLD were found to be significantly correlated. In the overall group, the FD-OCT-measured MLA and MLD have shown moderate diagnostic efficiency in the functional evaluation of significant stenosis. FD-OCT-measured MLA has high diagnostic efficiency in identifying severe coronary stenosis in vessels having reference diameter <3 mm.