Postconditioning in ST-elevation Myocardial Infarction (POSTEMI)

Study objectives: To assess the effects of postconditioning on infarct size in patients with ST-elevation infarction referred to PCI.

Study design: Prospective, randomized, open-label study with blinded endpoint evaluation. Included patients will be randomly allocated to postconditioning or control. Patients with symptoms of acute myocardial infarction of less than 6 hours duration fulfilling ECG criteria for primary PCI are eligible. PCI follow established routines. In postconditioning patients, additional, short (1 min), intermittent balloon occlusions will be applied after initial opening of infarct related artery. After this intervention, PCI proceeds routinely with stent implantation. In the control group, stent implantation after initial opening proceeds as usual. Primary endpoint is final infarct size, determined by MRI after 4 months. 260 patients will be included. Follow-up is 1 year. Inclusion period: 18 - 24 months.

Clinical implications: Reperfusion therapy, administered as early as possible after start of symptoms, has improved the prognosis in acute ST-elevation myocardial infarction. Still, however, many patients suffer large infarctions, subsequently with an increased risk of heart failure, arrhythmias, and death. In pilot studies, mechanical postconditioning has been shown to reduce infarct size and thus potentially improve prognosis. However, the effect of postconditioning must be confirmed in larger clinical trials before implemented in routine treatment.