Optical Coherence Tomography-Derived Anatomical Criteria for Functionally Significant Coronary Stenosis Assessed by Fractional Flow Reserve

Abstract

Background: For the identification of functionally significant coronary artery disease, there have not been any dedicated optical coherence tomography (OCT) studies reported previously, although OCT can clearly detect coronary vessel lumina at higher resolution than intravascular ultrasound (IVUS). Methods and Results: OCT and fractional flow reserve (FFR) measurements were performed in 62 intermediate coronary lesions in 59 patients. FFR was calculated as the ratio of distal coronary pressure divided by proximal coronary pressure during maximal hyperemia. FFR <0.75 was used as the threshold for diagnosing functionally significant stenosis. Minimal lumen area (MLA), minimal lumen diameter (MLD) and percent lumen area stenosis were measured by OCT. FFR values correlated significantly with OCT-derived MLA (r=0.75, P<0.01), MLD (r=0.76, P<0.01) and percent lumen area stenosis (r=−0.77, P<0.01). Receiver-operating characteristic curve suggested an OCT-derived MLA <1.91mm² (sensitivity 93.5%, specificity 77.4%), MLD <1.35mm (sensitivity 90.3%, specificity 80.6%) and percent lumen area stenosis >70.0% (sensitivity 96.8%, specificity 83.9%) as the best cutoff values for a FFR <0.75. Conclusions: Anatomical measurements of coronary stenosis obtained by OCT show significant correlation with FFR. OCT has the potential to predict functionally significant stenosis, although the present OCT-derived parameters were smaller than those reported in previous IVUS studies.  (Circ J 2012; 76: 2218–2225)