In a multicenter , double-blind , randomized trial , we assigned 970 patients with an acute anterior ST-segment elevation myocardial infarction ( STEMI ) who were undergoing percutaneous coronary intervention ( PCI ) within 12 hours after symptom onset and who had complete occlusion of the culprit coronary artery to receive a bolus injection of cyclosporine ( administered intravenously at a dose of 2.5 mg per kilogram of body weight ) or matching placebo before coronary recanalization .