Supersaturated oxygen therapy in patients with acute anterior myocardial infarction reduces infarct size

Abstract Background Myocardial final infarct size (FIS) is associated with heart failure hospitalizations and mortality in patients with ST-segment elevation myocardial infarction (STEMI). Interventional therapies beyond primary percutaneous coronary intervention (PCI) to reduce FIS are needed. Hyperoxemic supersaturated oxygen therapy (SSO2) has shown to reduce infarct size in previous clinical trials. Methods We performed routine SSO2 therapy in patients with acute anterior STEMI after successful primary PCI. Results from 22 SSO2 patients were compared with those from 22 pair-matched non-SSO2 acute anterior STEMI patients. Cardiac magnetic resonance imaging (MRI) was performed to assess left ventricular (LV) function, myocardial FIS (late gadolinium enhancement), area-at-risk (AAR, myocardial oedema), myocardial salvage index (MSI, proportion of non-necrotic inside oedematous myocardium), and microvascular obstruction (MVO, necrotic myocardium within the infarct zone). Results Both groups did not significantly differ regarding sex, age, weight, body mass index, hypertension, dyslipidaemia, smoking and diabetes status, prehospital cardiac arrest, door-to-balloon time, TIMI flow before and after PCI, numbers of stents placed, and renal function (p>0.1 each). SSO2 patients had significant lower maximum creatine kinase levels (2111 U/l) vs. non-SSO2 patients (4571 U/l, p=0.003). Cardiac MRI was performed 4 ± 2 days after PCI. LV ejection fraction (48% in SSO2 vs. 43% in non-SSO2, p=0.11) and AAR (42% of LV mass in SSO2 vs. 48% of LV mass in non-SSO2, p=0.096) did not significantly differ between the groups. SSO2 significantly reduced FIS by 38% (21% of LV mass vs. 34% of LV mass, p<0.001). MSI was significantly higher in SSO2 patients (46% vs. 18%, p<0.001). MVO occurred in 60% of SSO2 patients vs. 90% of non-SSO2 patients with a significant absolute difference (2.3% in SSO2 vs. 5.7% in non-SSO2, p=0.011). Conclusion While areas at risk were similar between both groups, SSO2 significantly reduced maximum creatine kinase levels, final infarct size and microvascular obstruction in patients with acute anterior STEMI.