Pre-treatment with statins decreased the incidence of cardiac enzyme increase after percutaneous coronary intervention (PCI) and distal embolization suspected to cause post-PCI myocardial damage. This study evaluates the effect of high dose atorvastatin pre-treatment on post-procedural index of microcirculatory resistance (IMR) values that are introduced for assessing the status of the microcirculation.

One hundred patients with non-ST elevation acute coronary syndrome will be randomly assigned to either high dose atorvastatin pre-treatment group(80 mg loading within 24 hours plus 40mg busting within 2 hours before PCI) or control group(atorvastatin 10mg administration within 24 hours before PCI). An intracoronary pressure/temperature sensor-tipped guidewire is used. Thermodilution curves are obtained during maximal hyperemia. The IMR was calculated from the ratio of the mean distal coronary pressure at maximal hyperemia to the inverse of mean hyperemic transit time. Creatine kinase-myocardial band(CK-MB) and CRP level will be measured at baseline and at 12~24 hours after PCI.

Inclusion Criteria:

• Patients of Non-ST elevation acute coronary syndrome planed to elective percutaneous coronary intervention

Exclusion Criteria:

• ST elevation myocardial infarction
• Cardiogenic shock
• Congestive heart failure with pulmonary edema
• Severe left ventricular dysfunction (LVEF < 30%)
• History of previous coronary revascularization therapy
• chronic total coronary occlusion
• 3 vessel disease
• Target lesion at distal segments or branches
• Ostial lesion
• Excessive coronary calcification or thrombi
• Elevated transaminase
• Renal dysfunction (serum creatinine > 2.0mg/dL
• History of myopathy
• Contra-indication to anti-platelet therapy
• Not indicated for percutaneous coronary intervention
• Other co-morbidity with life expectancy less than 1 year