Japan Assessment of Pitavastatin and Atorvastatin in Acute Coronary Syndrome (JAPAN-ACS)

Inclusion Criteria: * Patients with written consent by their own volition after being provided sufficient explanation for their participation in this clinical trial * Patients 20 years or older at the time of their consent * Patients with hypercholesterolemia as defined by any of the following criteria: * TC \>= 220 mg/dL; * LDL-C \>= 140 mg/dL; * Cholesterol-lowering treatment is necessary in accordance with the investigator's judgement when LDL-C \>= 100 mg/dL or TC \>= 180 mg/dL. * Patients who have been diagnosed with acute coronary syndrome * Patients with successful percutaneous coronary intervention (PCI) by intravascular ultrasound (IVUS) guidance * Patients having coronary plaques (\>= 500 µm in thickness or 20% or more in % plaque) at \>= 5 mm from the previously treated area in the same branch of coronary artery Exclusion Criteria: * Patients with bypass graft or in-stent restenosis at the site of PCI * Patients who had received PCI on the lesion in the past where the evaluation of coronary plaque volume is planned * Patients who had plaques in a non-culprit site and might receive PCI during the treatment period * Patients receiving lipid-lowering drugs (statins, fibrates, probucol, nicotinic acid or cholesterol absorption inhibitors) * Patients with familial hypercholesterolemia * Patients with cardiogenic shock * Patients receiving cyclosporine * Patients with any allergy to pitavastatin or atorvastatin * Patients with hepatobiliary disorders * Pregnant…