Determination of the Role of Oxygen on Mechanisms Involved in Ischemia-reperfusion Injury in Suspected Acute Myocardial Infarction by Biomarkers. A Sub Study to the DETO2X-AMI Trial.

Oxygen treatment is widely used in acutely ill patients, both pre-hospital and in hospital. The indication for oxygen is sometimes unquestionable, such as in many hypoxic patients, but in other situations its use is more of a practise and much less based on scientific evidence. In particular, oxygen treatment is routinely used in patients with a suspected heart attack and variably recommended in guidelines, despite very limited data supporting a beneficial effect. Indeed, a few studies even indicate that oxygen treatment might be harmful.

Immediate re-opening of the acutely blocked artery to the heart muscle is the treatment of choice to limit permanent injury. However, the sudden re-initiation of blood flow achieved with primary percutaneous coronary intervention (PCI), the reopening and stenting of the blocked vessel, can give rise to further endothelial and myocardial damage, so-called reperfusion injury. Ischemia and reperfusion associated myocardial injury (IR-injury) involves a wide range of pathological processes. Vascular leakage, activation of cell death programs, thrombocytes and white blood cells leading to extended inflammation and formation of clots are examples of those effects.

The role of oxygen treatment on these pathological processes, on the extent of IR-injury and the final infarct size in patients with acute myocardial infarctions (AMI) has not previously been studied.

In an ongoing national multicentre, randomized, registry based clinical trial, the DETO2X-AMI trial (NCT01787110), the effect of oxygen on morbidity and mortality in ACS patients is being investigated.

The present DETO2X-biomarkers study is a substudy of the DETO2X-AMI trial, evaluating the effect of oxygen treatment on biological systems involved in the pathogenesis of reversible and irreversible myocardial damage and cell death in ACS.