PROVE IT is an international, multicenter, randomized, double-blind, 2×2 factorial, parallel-group design trial (Figure 1). To be included in the study, a patient had to be hospitalized for acute myocardial infarction or high-risk unstable angina within the preceding 10 days. All patients had to have a total cholesterol level ≤240 mg/dl. The patient had to be in stable condition at the time of enrollment. The exclusion criteria included current statin therapy at a dose of 80 mg/day, or current lipid-lowering therapy with fibric acid derivatives or niacin. Subjects are being followed on an intent-to-treat basis. Clinical laboratory safety assessments and lipid measurements take place at the randomization visit, after 30 days, and after 4, 8, and 16 months of treatment, and at the final study visit. All patients receive dietary counseling at each scheduled visit to promote compliance with a National Cholesterol Education　Program diet.1 Study duration will be a minimum of 18 months; expected mean duration of follow-up is expected to be 2 years. The trial will continue until ≤925 events are achieved (i.e., an “event-driven” trial design); thus, the average duration of follow-up may extend beyond 2 years.（表1） Substudies include assessment of lipids, inflammatory markers, an electrocardiographic substudy to assess　the potential impact of gatifloxacin treatment on the QTc interval in ≥750 patients, endothelial function, resource utilization, and antibiotic resistance surveillance(cultures will be collected from ≥200 subjects at every visit). The primary efficacy outcome measure is time from randomization until first occurrence of a component of the primary end point: all-cause death, myocardial infarction, documented unstable angina requiring rehospitalization, revascularization (coronary artery bypass grafting or percutaneous coronary intervention) occurring≥30 days after randomization, and stroke. Secondary outcomes include components of the primary end point and an evaluation of the relation between the change from baseline of high-sensitivity C-reactive protein and the risk of a primary or secondary end points within each treatment group. Tertiary outcome measures will include evaluation of blood lipid levels, fibrinogen, isoprostanes, and C. pneumoniae immunoglobulin-G antibody by microimmunofluorescence at baseline, month 4, and final study visit. Screening for emergence of fluoroquinolone resistance will be determined by rectal swab cultures to monitor for Eschericia coli serially throughout the trial in a subset of patients. The independent Data Safety Monitoring Board will periodically review safety and efficacy results throughout the trial. The primary analyses will examine the main effect of pravastatin versus atorvastatin and gatifloxacin versus placebo. For the statin comparison of “clinical equivalence”or “sufficiency,” the sample size of 2,000 subjects in each of the 2 statin arms will afford 87% power to demonstrate that the relative 2-year cardiovascular event risk of pravastatin relative to atorvastatin is not >1.17 (that is, the upper 95% confidence limit of the relative risk between the 2 agents can be no worse than 1.17). With this sample size, clinical equivalence would be declared only if the 2 regimens are within an absolute event rate of 1.2% (e.g., 22% for atorvastatin vs <23.2% for pravastatin). These power calculations are based on the assumption of an event rate of 22% in the atorvastatin arm for a period of 2 years, with 1-year accrual time and a minimum 1.5 years of follow-up time, requiring a total of 925 events, using a 1-sided significance level of P=0.05 and the Lachin and Foulkes4 method. For the gatifloxacin comparison, the trial will have 94% power to detect a relative 19% difference between the antibiotic and placebo.