Standard treatment of patients with acute ST-segment elevation myocardial infarction consist of acute re-opening of the occluded coronary artery (primary PCI). Despite successful treatment of the epicardial vessel reperfusion is sometimes inadequate leading to large final infarct sizes. This phenomenon is known as the reperfusion injury. Several animal studies have indicated that graded re-opening of the artery may limit tissue damage. Generally this is referred to as mechanical postconditioning.