The Official Journal of EuroPCR and the European Association of Percutaneous Coronary Interventions (EAPCI)
Optical Flow Ratio for Assessing Stenting Result and Physiological Significance of Residual Disease
Daixin Ding1; Wei Yu2; Hélène Tauzin3; Giovanni Luigi De Maria4; Peng Wu2; Fan Yang2; Rafail A. Kotronias4; Dimitrios Terentes-Printzios4; Mathias Wolfrum4; Adrian P. Banning4; Nicolas Meneveau3; William Wijns5; Shengxian Tu2;
1. Biomedical Instrument Institute, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China; The Lambe Institute for Translational Medicine and Curam, National University of Ireland Galway, Ireland 2. Biomedical Instrument Institute, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China, China 3. Department of Cardiology, University Hospital Jean Minjoz, Besançon, France 4. Oxford Heart Centre, John Radcliffe Hospital, Oxford University Hospitals, NHS Foundation Trust, Oxford, United Kingdom 5. The Lambe Institute for Translational Medicine and Curam, National University of Ireland Galway, Ireland
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Background: Optical flow ratio (OFR) is a novel method for fast computation of fractional flow reserve (FFR) from optical coherence tomography (OCT) images.
Aims: We aimed to evaluate the accuracy of OFR in predicting post-percutaneous coronary intervention (PCI) FFR and to evaluate the impact of stent expansion on within-stent OFR pressure drop (In-stent OFR).
Methods: Post-PCI OFR was computed in patients with both OCT and FFR interrogation immediately after PCI. Calculation of post-PCI OFR (called simulated residual OFR) from pre-PCI OCT pullbacks after elimination of the stenotic segment by virtual stenting was performed in a subgroup of patients who had pre-PCI OCT images. Stent underexpansion was quantified by the minimum expansion index (MEI) of the stented segment.
Results: A total of 125 paired comparisons between post-PCI OFR and FFR were obtained in 119 patients, among which simulated residual OFR was obtained in 64 vessels. Mean post-PCI FFR was 0.92 ± 0.05. Post-PCI OFR showed good correlation (r = 0.74, p<0.001) and agreement (mean difference = -0.01 ± 0.03, p = 0.051) with FFR. The accuracy in predicting post-PCI FFR≤0.90 was 84% for post-PCI OFR. Simulated residual OFR significantly correlated with post-PCI FFR (r = 0.42, p<0.001). MEI showed moderate correlation (r=-0.49, p<0.001) with In-stent OFR.
Conclusions: Post-PCI OFR showed good diagnostic concordance with post-PCI FFR. Simulated residual OFR significantly correlated with post-PCI FFR. Stent underexpansion significantly correlated with in-stent pressure drop.