arge-scale clinical studies have recently shown an inhibitory effect on cardiovascular events of lipidlowering therapy with HMG-CoA reductase inhibitors (statins), indicating the usefulness of this therapy. [1][2][3][4][5][6][7][8] The benefit is particularly marked in patients with coronary heart disease (CHD), and the guidelines of the American National Cholesterol Education Program (NCEP) Adult Treatment Panel (ATP) III positively state the utility of lipid-lowering therapy in reducing low-density lipoprotein (LDL)-cholesterol (C) to below 70 mg/dl in patients with coronary artery disease. 9 In Japan, the guidelines for prevention of arteriosclerotic diseases specify a target value of LDL-C of less than 100 mg/dl for control of CHD patients in category C. 10 Evaluation of coronary arterial plaques by imaging diagnosis has progressed markedly in recent years. In the REVERSAL study, intravascular ultrasonography (IVUS) was used to compare the effect of lipid-lowering therapy between CHD patients treated with standard and active regimens, with the latter found to inhibit expansion of coronary plaques. 11 Size reduction of coronary plaques on IVUS by statin treatment in patients with acute coronary syndrome (ACS) has also been reported in Japan (the ESTABLISH study). 12 Subsequent multicenter studies such as the JAPAN-ACS study have verified the ESTABLISH results through investigation of strong statin-induced volume reduction of coronary plaques. [13][14][15] However, these studies have all evaluated quantitative changes of the plaques, and there have been fewer qualitative evaluations. 16 Spectral analysis of IVUS radiofrequency (RF) data can provide detailed quantitative and qualitative information on coronary plaque composition in vivo. [17][18][19][20][21] Nasu et al found that in vivo characterization of coronary plaques by 'virtual histology (VH)' correlated favorably with the results of in vitro histopathological examination of tissue samples obtained by directional coronary atherectomy. 22 In this study, we used VH-IVUS to evaluate short-term quantitative and qualitative changes in non-culprit lesions in a comparison of pitavastatin, a new strong statin, with atorvastatin after administration in the early stage (2-3 weeks) after onset of ACS. The follow-up period of 2-3 weeks was chosen to evaluate the inhibition of short-term events within 1 month by early statin administration after ACS onset, and to examine if the statin effect starts to appear in this period.
Methods
Study Design and Patient PopulationThe study was performed as a prospective, randomized, single-center trial to assess the effect of 2-to 3-weeks of (Received November 5, 2008 Patients with acute coronary syndrome who underwent emergency percutaneous coronary intervention (PCI) were randomly assigned to receive pitavastatin (n=80; 2 mg/day) or atorvastatin (n=80; 10 mg/day) immediately after PCI. All patients underwent a blood lipid test and VH-IVUS evaluation of non-PCI lesions at admission and after 2-3 weeks of statin administration. A...