Morphological features of coronary arteries in patients with coronary spastic angina: Assessment with intracoronary optical coherence tomography ☆ Yoshinobu Morikawa, Shiro Uemura ⁎, Ken-ichi Ishigami, Tsunenari Soeda, Satoshi Okayama, Yasuhiro Takemoto, Kenji Onoue, Satoshi Somekawa, Taku Nishida, Yukiji Takeda, Hiroyuki Kawata, Manabu Horii, Yoshihiko Saito First Department of Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8522, Japan abstract article info Article history: Received 2 April 2009 Received in revised form 2 July 2009 Accepted 19 July 2009 Available online 27 August 2009 Keywords: Coronary vasospasm Optical coherence tomography Angina pectoris Background: Coronary spasm (CS) plays an important role in the pathogenesis of many types of ischemic heart disease, but morphological appearance of non-stenotic coronary segments with CS is not fully understood. We evaluate the morphological characteristics of coronary arteries in patients with coronary spastic angina (CSA) using intravascular optical coherence tomography (OCT). Methods: We evaluated 37 patients with resting chest pain whose coronary angiograms did not reveal significant stenosis. These patients underwent an acetylcholine (ACh) provocation test. OCT was performed after complete dilatation of coronary arteries, and additionally during ACh-induced CS in four patients. Results: Based on the ACh test, 23 patients were diagnosed as having CSA, and the remaining 14 patients without CS were referred to as CS-negative. OCT study revealed that coronary segments with ACh-induced CS had homogeneous intimal thickening, and quantitative analysis showed that CS-positive segments had a significantly greater intima area as compared with corresponding CS-negative segments without lipid or calcium content. By contrast, CS-positive segments had a significantly smaller intima area as compared with CS-negative segments with lipid or calcium deposit. During ACh-induced CS, lumen and total vascular areas were significantly decreased, whereas intima area did not change in comparison with complete vasodilatation. The luminal surface of the intima formed a markedly wavy configuration during CS. Conclusions: Coronary artery segments involved in CS are characterized by diffuse intimal thickening without lipid or calcium content. High-resolution coronary OCT imaging could make it possible to analyze the vascular pathophysiology in patients with CS. © 2009 Elsevier Ireland Ltd. All rights reserved. 1. Introduction Coronary spasm (CS) plays an important role in the pathogenesis of many types of ischemic heart disease, including unstable angina pectoris, acute myocardial infarction, and sudden cardiac death [1–4]. Previous studies have indicated that endothelial dysfunction of coronary arteries plays a pivotal role in the development of CS [5,6], and CS occurs in both patients with normal coronary angiograms and also in those with atherosclerotic coronary stenosis [7–9]. For the differential diagnosis of CS, provocation tests using acetylcholine (ACh) or ergonovine are usually performed, and intracoronary injection of ACh is reported to be sensitive (N 90%) and reliable for the diagnosis of CS [10,11]. However, the above provocation tests are not always tolerable or safe due to the induction of severe ischemia and lethal arrhythmias [12]. Accordingly, it seems very important to clarify the morphologic features of coronary arteries that are prone to developing CS, especially in patients with normal coronary angiograms. Based on such perspective, several researchers have already investi- gated the morphological characteristics of coronary artery segments undergoing CS by using intravascular ultrasound (IVUS) [13–15], and several features of coronary artery wall were reported to correlate with the development of CS. Although IVUS is very sensitive for the detection of total wall thickness and calcium content in coronary arteries, it cannot visualize the borderline between intima and media, as well as not precisely differentiate other characteristics of vascular wall, such as accumulation of fibrous or lipid-containing tissue. Intravascular optical coherence tomography (OCT) is a newly developed intravascular imaging modality that provides cross- sectional images of tissue with a resolution of 10 μm, allowing high- resolution visualization of the vascular wall and atherosclerotic plaque morphology [16,17]. This new technique enabled us not only to quantify the vascular wall thickness, but also to differentiate between the pathological changes occurring in the coronary arterial International Journal of Cardiology 146 (2011) 334–340 ☆ This study was supported in part by research grants from the Japanese Ministry of Education, Culture, Sports, Science and Technology and by research grant for Cardiovascular Diseases (20A-3) from the Japanese Ministry of Health and Labor and Welfare. ⁎ Corresponding author. Tel.: +81 744 22 3051x3411; fax: +81 744 22 9726. E-mail address: suemura@naramed-u.ac.jp (S. Uemura). 0167-5273/$ – see front matter © 2009 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ijcard.2009.07.011 Contents lists available at ScienceDirect International Journal of Cardiology journal homepage: www.elsevier.com/locate/ijcard