Evaluation of intracoronary hyperoxemic oxygen therapy in acute anterior myocardial infarction: The IC-HOT study

Background: In the randomized AMIHOT-II trial, supersaturated oxygen [SSO ₂ ] delivered into the left anterior descending (LAD) artery via an indwelling intracoronary infusion catheter following primary percutaneous coronary intervention (PCI) significantly reduced infarct size in patients with anterior ST-segment elevation myocardial infarction (STEMI) but resulted in a numerically higher incidence of safety events. Objectives: The IC-HOT study evaluated the safety of SSO ₂ therapy selectively delivered to the left main coronary artery (LMCA) for 60 minutes after PCI in patients with anterior STEMI. Methods: SSO ₂ therapy was administered to the LMCA after stent implantation in 100 patients with anterior STEMI and proximal or mid-LAD occlusion presenting within 6 hours of symptom onset. The primary endpoint was the 30-day composite rate of net adverse clinical events (NACE) (death, reinfarction, clinically driven target vessel revascularization, stent thrombosis, severe heart failure, or TIMI major/minor bleeding) compared against an objective performance goal of 10.7%. Cardiac magnetic resonance imaging was performed at 4 and 30 days to assess infarct size. Results: SSO ₂ delivery was successful in 98% of patients. NACE at 30 days occurred 7.1% of patients (meeting the primary safety endpoint of the study); there were no deaths, only one stent thrombosis and one case of severe heart failure. Median [interquartile range] infarct size was 24.1% [14.4%, 31.6%] at 4 days and 19.4% [8.8%, 28.9%] at 30 days. Conclusion: Following primary PCI in acute anterior STEMI, infusion of SSO ₂ via the LMCA was feasible and was associated with a favorable early safety profile.