Comparison by Optical Coherence Tomography of the Frequency of Lipid Coronary Plaques in Current Smokers, Former Smokers, and Nonsmokers Farhad Abtahian, MD, PhDa,1, Taishi Yonetsu, MDb,1, Koji Kato, MD, PhDc, Haibo Jia, MD, PhDa,b, Rocco Vergallo, MDa, Jinwei Tian, MD, PhDa,d, Sining Hu, MDa,d, Iris McNulty, RNa, Hang Lee, PhDe, Bo Yu, MD, PhDd,1, and Ik-Kyung Jang, MD, PhDa,*,1 Smoking is associated with high incidence of cardiovascular events including acute coronary syndrome. We sought to characterize coronary plaques in patients with ongoing smoking using optical coherence tomography (OCT) compared with former smokers and nonsmokers. We identified 465 coronary plaques from 182 subjects who underwent OCT imaging for all 3 coronary arteries. Subjects were divided into 3 groups: current smokers (n [ 41), former smokers (n [ 67), and nonsmokers (n [ 74). OCT analysis included the presence of lipid-rich plaque, thin-cap fibroatheroma (TCFA), calcification, maximum lipid arc, lipid core length, lipid index, and fibrous cap thickness. Lipid index was defined by mean lipid arc multiplied by lipid core length. Compared with former smokers and nonsmokers, the incidence of lipid plaques and TCFA was significantly higher in current smokers (lipid plaques: 68.0% vs 45.9% and 52.6%, p [ 0.002; TCFA: 18.4% vs 7.6% and 9.9%, p [ 0.018). There was a trend for higher plaque disruption in current smokers. Former smokers were more likely to have calcified plaques than current and nonsmokers (52.9% vs 32.0% and 38.0%, p [ 0.001). In a multivariate analysis, current smoking, low-density lipoprotein, and presentation with acute coronary syndrome were independently associated with the presence of TCFAs. In conclusion, current smokers are more likely to have lipid plaques and OCT-defined vulnerable plaques (TCFAs). Former smokers have increased number of calcified plaques. These results may explain the increased risk of acute cardiac events among smokers. Ó 2014 Elsevier Inc. All rights reserved. (Am J Cardiol 2014;114:674e680) Smoking is a significant contributor to cardiovascular disease and by recent estimates results in >1 million cardiovascular deaths annually worldwide.1 More specifically, smoking is a major risk factor for acute coronary syndrome (ACS) and sudden cardiac death.2,3 Smoking is believed to increase the burden of cardiovascular disease by inducing endothelial dysfunction, increasing the burden of coronary atherosclerosis and increasing the risk of thrombosis.4 Optical coherence tomography (OCT) is an intravascular imaging technique that allows visualization of coronary arteries with high resolution.5 OCT can provide detailed in vivo information on atherosclerotic plaques inside vessels, including tissue characteristics and fibrous cap thickness. In this study, using a data set from 182 patients who underwent

a

Cardiology Division and eBiostatistics Center, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts; bDepartment of Cardiology, Kameda Medical Center, Chiba, Japan; cDepartment of Cardiovascular Medicine, Nippon Medical School, Tokyo, Japan; and d Department of Cardiology, 2nd Affiliated Hospital of Harbin Medical University, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, China. Manuscript received March 14, 2014; revised manuscript received and accepted May 30, 2014. See page 679 for disclosure information. *Corresponding author: Tel: (617) 726-9226; fax: (617) 726-7419. E-mail address: [email protected] (I.-K. Jang). 1

These authors contributed equally.

0002-9149/14/$ - see front matter Ó 2014 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.amjcard.2014.05.056

OCT imaging of all 3 epicardial vessels, we sought to correlate smoking history (current, former, and never) with coronary plaque characteristics as identified by OCT. Methods The Massachusetts General Hospital OCT registry is a multicenter registry of patients who underwent OCT of the coronary arteries and includes 20 sites across 6 countries. From a total of 1,406 patients who were enrolled in the registry between August 2010 and May 2012, we identified 198 patients who underwent OCT imaging of all 3 major epicardial coronary arteries. From this cohort, we selected the patients who had at least 1 nonculprit or nontarget coronary plaques with area stenosis >50% as measured by OCT using the Working Group for Intravascular Optical Coherence Tomography Standardization and Validation definition for stenosis.6 Stenoses at sites of previous stenting and those that required balloon angioplasty before OCT imaging were excluded. Patients with incomplete clinical histories or laboratory data were also excluded. The final data set included 182 subjects with 465 nonculprit plaques. Subjects were divided into 3 groups: current active smokers (103 plaques in 41 subjects), former smokers who had quit at least 3 months before (170 plaques in 67 subjects), and those who had never smoked (192 plaques in 74 subjects). Patients with ACS included those presenting with STelevation myocardial infarction (STEMI), non-STEMI, and www.ajconline.org

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Figure 1. Representative images from OCT. (A) Lipid-rich plaque identified by a plaque with lipid involving >90 of the vessel wall circumference. (B) Calcified plaque identified by an area with low backscatter and a sharp border. (C) Plaque disruption showing a discontinuity of the fibrous cap. (D) TCFA defined as a lipid-rich plaque with a fibrous cap thickness