Effect of statin therapy on coronary fibrous-cap thickness in patients with acute coronary syndrome: Assessment by optical coherence tomography study

Background: The thickness of coronary fibrous caps is a major determinant of vulnerable plaques. Several clinical trials have suggested that statin therapy could stabilize vulnerable plaques. Recently, optical coherence tomography (OCT) has been proposed as an effective histology-resolution imaging modality for assessing such micro-structural changes. Methods: Forty AMI patients with hyperlipidemia were enrolled and underwent percutaneous coronary intervention (PCI). They were divided into two groups; statin treatment group (n=23) or control group (n=17). Serial OCT analyses were performed at baseline and 9-month follow-up for a non-PCI lipid-rich plaque lesion. Results: The LDL cholesterol level in the statin group was significantly lower than that in the control group at follow-up. Although the fibrous-cap thickness was significantly increased in both the statin treatment group (151 +/- 110 to 280 +/- 120 mu m, p<0.01) and the control group ( 153 +/- 116 to 179 +/- 124 mu m, p<0.01) during follow-up period, the degree of increase was significantly greater in the statin treatment group than in the control group (188 +/- 64% vs. 117 +/- 39%, p<0.01). Furthermore, when the patients in the statin treatment group were divided into two subgroups (fibrous-cap thickness <median and >= median), the thin fibrous-cap group (<median) increased their thickness much more than the thick fibrous-cap group (>= median). Conclusion: The lipid-lowering therapy with statin for 9 months after the onset of acute myocardial infarction significantly increased the fibrous-cap thickness in patients with hyperlipidemia. (C) 2008 Elsevier Ireland Ltd. All rights reserved.