Supersaturated oxygen therapy after primary PCI in anterior STEMI: Current evidence and clinical uncertainties

Even with timely reperfusion using primary percutaneous coronary intervention (PCI), patients with anterior ST-elevation myocardial infarction (STEMI) continue to remain at high risk of adverse outcomes, largely related to infarct size and microvascular injury. Supersaturated oxygen (SSO₂) therapy has been proposed as a catheter-based adjunctive strategy aimed at improving myocardial oxygen delivery following reperfusion in anterior STEMI. This narrative review evaluates current evidence on SSO₂, focusing mainly on its impact on infarct size, microvascular obstruction and on left ventricular ejection fraction (LVEF). Evidence regarding LVEF remains limited and somewhat inconsistent, with most findings coming from relatively small studies. In contrast, improvements in microvascular parameters such as microvascular obstruction (MVO), lower index of microcirculatory resistance (IMR) and myocardial salvage index (MSI), suggest that the benefit of SSO₂ therapy may be greatest in patients with impaired microvascular function. However, these improvements in surrogate markers have not translated into consistent reductions in major adverse cardiovascular events (MACE) or mortality. Overall, SSO₂ therapy represents a promising adjunct in anterior STEMI, but its clinical value remains uncertain. Further large-scale randomized trials are needed to define its role in routine practice.