Cardiovascular Revascularization Medicine Available online 24 June 2014 Optical coherence tomography for guiding wire into a side branch coronary artery with flush total occlusion ☆ Yasir H. Qureshi a , Giora Weisz a, b , Akiko Maehara b , Diaa A. Hakim a , Khady Fall a , Angelica Castaneda a , Jeffrey W. Moses a, b, , Show more doi:10.1016/j.carrev.2014.06.002 Abstract We report a case of flush occlusion, where a novel use of optical coherence tomography (OCT) helped in successful crossing and stenting of the lesion. Keywords Optical coherence tomography (OCT); Total occlusion; CTO; Complex PCI 1. Introduction A third of patients undergoing percutaneous coronary intervention (PCI) are diagnosed with chronic total occlusions (CTO), however, only 8–15% of all attempted PCIs in USA are Coronary CTOs [1], [2] and [3]. CTO revascularization remains a challenging technique, high atherosclerotic plaque burden, heavily calcified fibrous cap, difficulty in crossing the lesion, complexity of the procedure and the potential for complications are the major reasons many CTOs have been regarded as generally unsuitable for PCI. Total occlusion was the most common (68%) angiographic exclusion criteria in the BARI study leading to bypass surgery [1]. CTO plaque is composed of lipids, smooth muscle cells, extracellular matrix (collagens), and calcium [1] and [4]. Proximal cap (PC) crossing is a difficult step during CTO revascularization, PC varies in morphology, composition (fatty, fibrous, calcified) and presence or absence of micro-channels (MC) [4], [5] and [6]. These variations can affect outcomes of CTO interventions; however, major barrier to success is the so called blunt stump. Intravascular ultrasound (IVUS) has been used for characterization of PC, however, OCT is not. In this case we used OCT to visualize PC and MC of a flush total occlusion. Since forward looking catheters are not yet available, IVUS and OCT are limited to lateral imaging. To overcome this limitation we identified a side branch lesion with an occlusion flush with the main vessel. We performed an OCT run in the main vessel, to capture an image of side branch’ s ostial