Extent of the difference between microcatheter and pressure wire-derived fractional flow reserve and its relation to optical coherence tomography-derived parameters

• Main Authors: Yoshiki Matsuo, Yasutsugu Shiono, Kuninobu Kashiyama, Yasushi Ino, Takahiro Nishi, Kosei Terada, Hiroki Emori, Daisuke Higashioka, Yosuke Katayama, Amir Khalifa Mahfouz, Teruaki Wada, Suwako Fujita, Masahiro Takahata, Kunihiro Shimamura, Manabu Kashiwagi, Akio Kuroi, Atsushi Tanaka, Takeshi Hozumi, Takashi Kubo, Takashi Akasaka
• Format: Article
• Language: English
• Published: Elsevier 2020-04-01
• Series: International Journal of Cardiology: Heart & Vasculature
• Online Access: http://www.sciencedirect.com/science/article/pii/S235290672030052X

Background: Although previous studies demonstrated that microcatheter-derived fractional flow reserve (mc-FFR) tends to overestimate lesion severity compared to pressure wire-derived FFR (pw-FFR), the clinical utility of mc-FFR remains obscure. The extent of differences between the two FFR systems and its relation to a lesion-specific parameter remain unknown. In this study, we sought to compare mc-FFR with pw-FFR and determine the lower and upper mc-FFR cut-offs predicting ischemic and non-ischemic stenosis, using an ischemic and a clinical FFR threshold of 0.75 and 0.80 as references, respectively. We further explored optical coherence tomography (OCT) parameters influencing the difference in FFR between the two systems. Methods and results: In this study, 44 target vessels with intermediate de novo coronary artery lesion in 36 patients with stable ischemic heart disease were evaluated with mc-FFR, pw-FFR and OCT. Bland-Altman plots for mc-FFR versus pw-FFR showed a bias of −0.04 for lower mc-FFR values compared to pw-FFR values. The mc-FFR cut-off values of 0.73 and 0.79 corresponded to the 0.75 ischemic pw-FFR and 0.80 clinical pw-FFR thresholds with high predictive values, respectively. The differences in the two FFR measurements (pw-FFR minus mc-FFR) were negatively correlated with OCT-derived minimum lumen area (MLA) (R = −0.359, p = 0.011). The OCT-derived MLA of 1.36 mm2 was a cut-off value for predicting the clinically significant difference between the two FFR measurements defined as >0.03. Conclusion: Mc-FFR is clinically useful when the specific cut-offs are applied. An OCT-derived MLA accounts for the clinically significant difference in FFR between the two systems. Keywords: Fractional flow reserve, Microcatheter, Pressure wire, Optical coherence tomography, Decision-making, Minimum lumen area