Letter to the Editor Coronary aneurysm reduced after coronary stenting Masashi Ohtsuka a, ⁎ , Eiji Uchida a , Hiroyuki Yamaguchi a , Toru Nakajima a , Hiroshi Akazawa b , Nobusada Funabashi, Yoshio Kobayashi b , Ichiro Shiojima b , Issei Komuro b a Department of Cardiology, Seirei Yokohama General Hospital, 215 Iwai-cho, Hodogaya-ku, Yokohama 240-8521, Japan b Cardiovascular Science and Medicine, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670, Japan Received 16 July 2006; accepted 2 August 2006 Available online 13 November 2006 Abstract We describe as case of a 70-year-old man who underwent a percutaneous coronary intervention with stenting, for a severe stenosis complicated by a coronary aneurysm just distal to the stenotic site. Notably, coronary angiogram showed an immediate and progressive reduction in the size of coronary aneurysm. Curved planar reconstruction images of the enhanced CT showed no thrombus and no dissection of the coronary aneurysm. We speculate that coronary stenting might decrease the velocity of coronary flow through the stenosis. Consequently, stenting might attenuate the hydrodynamic wall stress on the aneurysm, and, in addtion, improve the degradation of the extracellular matrix structure through the regulation of matrix metalloproteinases. Regression of coronary aneurysm after stenting requires further investigations, because stenting may become a potential means for treating post-stenotic aneurysms. © 2006 Elsevier Ireland Ltd. All rights reserved. Keywords: Coronary aneurysm; Stenting; Myocardial infarction; Multi-slice computed tomography 1. Case report A 70-year-old man was admitted to hospital with chest tightness after riding a bicycle. An emergency coronary angi- ography was performed, which showed a severe coronary stenosis (99% TIMI 1, arrowhead Fig. 1A) at the mid-portion of the left anterior descending (LAD) coronary artery, with a coronary aneurysm 5.3 mm in diameter (arrow in Fig. 1A), just distal to the stenotic site. Coronary blood flow was promptly restored by primary percutaneous coronary intervention (PCI) with coronary stenting, and immediately afterwards, the diameter of the coronary aneurysm was reduced to 4.8 mm (arrow in Fig. 1B). The patient recovered and was discharged home. A follow-up coronary angiography 7 months later, showed that the coronary artery was patent and the diameter of coronary aneurysm was further reduced to 3.3 mm (arrow in Fig. 1C). The composition of the coronary aneurysm was then examined using a 64-slice computed tomography (CT) (Aquilion 64, TOSHIBA). Curved planar reconstruction images of the enhanced CT showed no thrombus and no dissection of the coronary aneurysm (arrow in Fig. 2). 2. Discussion Coronary aneurysms are very common in the LAD coronary artery and rarely occur without severe stenosis [1]. To date, there have been no reports of a reduction in the size of such aneurysms after stenting. There are two possible mechanisms by which coronary stenting might cause this reduction. One is that it decreases the velocity of coronary flow through the stenosis and attenuates the hydrodynamic wall stress on the aneurysm. The resulting decrease in hemodynamic forces could reduce the size of aneurysm. A second mechanism is that stenting improves the degradation of the extracellular matrix structure through the regulation of matrix metalloproteinases (MMPs). MMPs have been reported to be implicated in the pathogenesis of aneurysm development through increased proteolysis of extracellular matrix proteins [2]. Furthermore, endothelial MMP-9 expression is coronary flow-sensitive and International Journal of Cardiology 121 (2007) 76 – 77 www.elsevier.com/locate/ijcard ⁎ Corresponding author. Tel.: +81 45 715 3111; fax: +81 45 715 3387. E-mail address: masaootsuka-circ@umin.ac.jp (M. Ohtsuka). 0167-5273/$ - see front matter © 2006 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ijcard.2006.08.020