Letter to the Editor OCT/atherectomy/pathology studies open new perspectives for in vivo characterization of plaque composition Eloisa Arbustini a, ⁎, Mario Urtis a , Francesco Prati b a Centre for Inherited Cardiovascular Diseases, Transplant Research Area - IRCCS Foundation Policlinico San Matteo Pavia, Italy b Interventional Cardiology Unit, San Giovanni Addolorata Hospital and CLI Foundation, Rome, Italy article info Article history: Received 21 September 2018 Accepted 29 October 2018 Available online xxxx Keywords: OCT Coronary atherectomy Macrophages Pathology Imaging Dear Editor, We read with interest the study by Habara et al. in IJC, October 2018 [1]. The authors performed OCT before and after directional coronary atherectomy (DCA) and correlated the OCT findings with histopatho- logical and immunohistochemical features of the plaque samples. The data are very encouraging in particular regarding the ability of OCT of recognizing macrophages in the superficial plaque layers. Imaging techniques able of distinguishing “cell phenotypes” need stringent evidence and validation. Recognizing inflammatory cells in vivo is current and clinically needed because their presence in vulnerable plaques increases the risk of plaque rupture. Past ex vivo OCT/pathology studies provided the basis for in vivo detection of macrophages by OCT (Consensus criteria) [2] now translating into novel clinical applications [3]. The study by Habara et al. is the first one in vivo that demonstrated high concordance between OCT and pathology detection of plaque macrophages. In a future perspective OCT/pathology studies should be paralleled by non-invasive coronary imaging in order to integrate information from multimodality imaging, useful for CT and CMR interpretation. This is for promoting the in vivo implementation of the non-invasive International Journal of Cardiology xxx (xxxx) xxx–xxx ⁎ Corresponding author at: Centre for Inherited Cardiovascular Diseases, IRCCS Fondazione Policlinico San Matteo, Piazzale Golgi 19, 27100 Pavia, Italy. E-mail address: e.arbustini@smatteo.pv.it (E. Arbustini). IJCA-27146; No of Pages 2 diagnosis of vulnerable coronary plaques and identification of patients at risk of acute events. A critical issue for replication of OCT/DCA/pathology studies is that plaque debulking is no longer needed. The clinical results of the past did not demonstrate superiority over any current revascularization procedure. However, special indications could emerge for novel DCA application [4] thanks to design innovation, like the new DCA catheters developed for bifurcations [5]. Conflict of interest The authors report no relationships that could be construed as a conflict of interest. Acknowledgments Research on vascular diseases is supported by CLI Foundation (Rome) (FP), and Ministry of Health to IRCCS Policlinico San Matteo, National Network for Cardiovascular Diseases, Pavia, Italy (MU, EA). References [1] M. Habara, F. Otsuka, E. Tsuchikane, M. Terashima, K. Nasu, Y. Kinoshita, A. Murata, Y. Suzuki, Y. Kawase, M. Okubo, H. Matsuo, T. Matsubara, S. Yasuda, H. Ishibashi-Ueda, T. Suzuki, In vivo tissue characterization of human atherosclerotic plaques by optical co- herence tomography: a directional coronary atherectomy study with histopathologic confirmation, Int. J. Cardiol. 268 (2018) 1–10. [2] G.J. Tearney, E. Regar, T. Akasaka, T. Adriaenssens, P. Barlis, H.G. Bezerra, B. Bouma, N. Bruining, J.M. Cho, S. Chowdhary, M.A. Costa, R. de Silva, J. Dijkstra, C. Di Mario, D. Dudek, E. Falk, M.D. Feldman, P. Fitzgerald, H.M. Garcia-Garcia, N. Gonzalo, J.F. Granada, G. Guagliumi, N.R. Holm, Y. Honda, F. Ikeno, M. Kawasaki, J. Kochman, L. Koltowski, T. Kubo, T. 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Contents lists available at ScienceDirect International Journal of Cardiology journal homepage: www.elsevier.com/locate/ijcard Please cite this article as: E. Arbustini, et al., OCT/atherectomy/pathology studies open new perspectives for in vivo characterization of plaque composition, Int J Cardiol (2018), https://doi.org/10.1016/j.ijcard.2018.10.105