Timing of cardiovascular magnetic resonance in clinical trials evaluating cardioprotective therapies to reduce infarct size

Although the short- and long-term clinical outcomes of patients with ST-segment elevation myocardial infarction (STEMI) has improved substantially over the last 2 decades the risk of future cardiovascular events, in particular heart failure, remains high [ 1 ]. The most important determinant of long-term clinical outcomes after STEMI is infarct size (IS). In a recent meta-analysis, IS measured within 1 month after primary percutaneous intervention (pPCI) was strongly associated with all-cause mortality and hospitalization for heart failure within 1 year [ 2 ]. There are currently no established therapies to reduce IS, with the exception of timely reperfusion by pPCI. Furthermore, ischemia-reperfusion injury (IRI) remains a major clinical problem in patients with STEMI, leading to greater IS, ventricular arrhythmias and heart failure, despite early reperfusion by pPCI. There are no effective therapies to prevent or limit IRI, which is caused by multiple pathways activated by rapid tissue reoxygenation and the generation of reactive oxygen species. Contemporary research focus is on new therapeutic interventions to reduce IRI and subsequent IS, with the ultimate aim of improving event-free survival in STEMI patients.