ORIGINAL PAPER Optical coherence tomography features of angiographic complex and smooth lesions in acute coronary syndromes Hesham Refaat • Giampaolo Niccoli • Mario Gramegna • Rocco A. Montone • Francesco Burzotta • Antonio M. Leone • Carlo Trani • Ahmed S. Ammar • Islam A. Elsherbiny • Giancarla Scalone • Francesco Prati • Filippo Crea Received: 29 November 2014 / Accepted: 22 February 2015 Ó Springer Science+Business Media Dordrecht 2015 Abstract Plaque rupture (PR) and superimposed throm- bosis have been shown as the most frequent underlying substrate in acute coronary syndromes (ACS). Coronary angiography is a luminogram not able to define in vivo fea- tures of the culprit plaques. The aim of the study was to use optical coherence tomography (OCT) to investigate the pathology underlying complex (CL) and non-complex an- giographic lesions (NCL). We retrospectively enrolled 107 ACS patients admitted to our institution; 83 with non-ST elevation ACS (NSTE-ACS) and 24 with ST-elevation my- ocardial infarction. Coronary angiography was performed and culprit lesions were classified according to Ambrose criteria into NCL (n = 47) and CL (n = 60). OCT imaging was then performed to better identify plaque morphology; either PR or intact fibrous cap, the presence of superimposed thrombosis, lipid rich plaque, and thin cap fibroatheroma (TCFA). OCT analysis showed that 58 lesions (54.2 %) were classified as PR and 48 lesions (44.9 %) were associated with thrombi. Lipid rich plaques were identified in 62 lesions (57.9 %). PR, intracoronary thrombi, lipid rich plaques and TCFA were more frequent in CL compared with NCL (71.7 vs 31.9 %, 63.3 vs 21.3 %, 71.7 vs 40.4 % and 46.7 vs 21.3 % respectively), but PR with superimposed thrombus may be also detected in NCL. OCT demonstrates PR and thrombosis in the majority of ACS patients presenting with CL. However, one-third of NCL show PR by OCT, sug- gesting that additional intracoronary imaging by OCT may better identify the underlying mechanism of coronary in- stability than coronary angiography alone. Keywords Acute coronary syndrome Á Optical coherence tomography Á Plaque rupture Á Thrombosis Á Complex lesions Introduction Acute coronary syndromes (ACS) are caused by sudden coronary thrombosis due to rupture of vulnerable plaques with a large lipid core or by erosion of endothelium within fibrous plaques in most of the cases [1]. For the last 50 years, coronary angiography has been utilized to study ACS features of culprit plaques. Complex angiographic lesions have been associated with ACS and related to a worse prognosis and disease progression [2]. However, as coronary angiography is a luminogram, it is plausible that even smooth culprit lesions may show features of com- plexity by intracoronary imaging with a high resolution [3]. Optical coherence tomography (OCT) is a recently de- veloped intravascular imaging modality using near-infrared Hesham Refaat and Giampaolo Niccoli have equally contributed to the manuscript as first authors. Electronic supplementary material The online version of this article (doi:10.1007/s10554-015-0632-z) contains supplementary material, which is available to authorized users. H. Refaat Á G. Niccoli (&) Á M. Gramegna Á R. A. Montone Á F. Burzotta Á A. M. Leone Á C. Trani Á G. Scalone Á F. Crea Institute of Cardiology, Catholic University of the Sacred Heart, Largo F. Vito 1, 00168 Rome, Italy e-mail: gniccoli73@hotmail.it H. Refaat Á A. S. Ammar Á I. A. Elsherbiny Cardiology Department, Zagazig University, Zagazig, Egypt F. Prati Centro per la Lotta contro l’Infarto - Fondazione Onlus, Rome, Italy F. Prati San Giovanni-Addolorata Hospital, Rome, Italy 123 Int J Cardiovasc Imaging DOI 10.1007/s10554-015-0632-z