Effects of Atorvastatin on Myonecrosis

Overview

This study is designed as a prospective, randomized, placebo-controlled, double-blind analysis of atorvastatin 80 mg versus placebo administered on average 4 hours prior to percutaneous coronary intervention \[PCI\] (at least 2 hours) in patients presenting with unstable angina. Only patients with negative cardiac biomarkers, measured on 2 separate occasions a few hours apart will be eligible for inclusion. Furthermore, patients already on high-dose statin therapy; patients taking any statin within 24 hours prior to the PCI; and patients with contraindications to statins will be excluded from the study. The primary endpoint is a quantitative troponin level at 18-24 hours after PCI. At an enrollment of a total of 150 patients (75 per group), the study is powered to detect a 30% difference in troponin level. Secondary endpoints include elevation of creatine kinase (CK) and CK-MB above the upper limit of normal, change in C-reactive protein (CRP) levels from baseline and thrombolysis in myocardial infarction (TIMI) myocardial perfusion grade. All patients will be started on statin therapy the day after the procedure, as deemed appropriate by their treating physicians.

STUDY OBJECTIVES: 1. The primary endpoint of the study is to evaluate the effects of a single high dose of atorvastatin versus placebo on peri-procedural myonecrosis, as measured by troponin T (TnT), during percutaneous coronary intervention (PCI) in patients presenting with acute coronary syndromes (ACS). 2. Secondary endpoints include the measurements of other biomarkers of myocyte injury (CK, CK-MB) and inflammation (CRP). 3. Other secondary endpoints include the relative angiographic efficacy of atorvastatin versus placebo on the post PCI growth of tissue level perfusion circumference and the post PCI growth of tissue level perfusion brightness using digital subtraction angiography. METHODS: I. Selection and Number of Patients The study subjects are to be selected from those patients presenting to the BIDMC for cardiac catheterization. Eligible patients will be identified in the cardiac catheterization holding area prior to their procedure. After obtaining informed consent, patients will be randomized to a single dose of atorvastatin or placebo, which will be administered in the holding area about 4 hours prior to the procedure. There will be a total of 150 subjects enrolled in the study. There are a total of 2500 PCIs performed at the BIDMC per year, a third of which are for ACS. We anticipate that 30-40% of patients with ACS will be eligible for study participation. II. Informed Consent Informed consent will be obtained from all individuals prior to enrolment in the study according to local Internal Review Board guidelines. III. Pretreatment Data Collection Baseline clinical data will be recorded at enrolment and will include: Subject's age, sex, weight and height, diabetes, hypertension, smoking status, hypercholesterolemia (including cholesterol levels if available), the presence of coronary or peripheral artery disease and prior history of PCI or coronary artery bypass surgery. Further, all current medications will be recorded. A detailed angina history will be collected from the patient and the medical record looking for evidence of unstable angina as defined by Braunwald. IV. Medications A. Study Medication Patients will be randomly assigned to atorvastatin 80 mg po or placebo in a double-blind fashion. The study medication will be administered immediately after informed consent is obtained and the patient is randomized to a treatment group in the cardiac catheterization holding area. Given the typical waiting time between first presentation in the holding area and PCI in a non-emergent case, it is estimated that the study medication will be administered 4 hours prior to the procedure (minimal time of 2 hours). All patients will receive a single dose of study medication prior to the procedure. After the completion of the procedure, all statin therapy will be withheld until the next day. Eligible patients can then receive statin therapy according to the treating physicians' preferences. All potential adverse reactions to the study medication will be recorded. B. Concomitant Therapy Aspirin (325 mg/day) will be administered prior to intervention and during follow-up. Clopidogrel (300 mg or 600 mg bolus followed by 75 mg/day) will be administered post-stent deployment. It is expected that the majority of patients will receive a glycoprotein IIb/IIIa inhibitor during the procedure and for 18 hours thereafter. V. Procedures A. Laboratory Tests At baseline, levels of troponin, CK and CK-MB will be obtained at the time of presentation and immediately prior to PCI. Patients with any of these serum markers above the upper limit of normal will be excluded from the study. Post-procedural enzymes will be obtained 6-8 hours after the procedure and the next morning (18-24 hours after the procedure). Patients with elevated enzymes may undergo further sampling to determine the peak enzyme rise. The peak troponin level obtained from any post-procedural blood draw will be used as the primary endpoint. Furthermore, baseline CRP levels will be obtained prior to PCI and on the next day. B. Digital Subtraction Angiography To quantitate the kinetics of dye entry into the myocardium, digital subtraction angiography can be used. Digital subtraction angiography will be performed at end diastole by aligning cineframe images before dye filled the myocardium with the frame in which dye first reached its peak brightness. The spine, ribs, diaphragm and the epicardial artery are then subtracted. A representative region of the myocardium is sampled that is free of overlap by epicardial arterial branches to determine the increase in the gray scale brightness of the myocardium. The circumference of the myocardial blush is measured using a handheld planimeter (Fowler, Inc). The frame count ÷ number of frames per second is used to measure the time elapsed during angiography to quantitate the rate of rise in the growth (cm/sec) and brightness (gray/sec) of myocardial blush. Blush will also be assessed visually using the TIMI myocardial perfusion grade.