Microvascular Obstruction in Patients With Anterior STEMI Treated With Supersaturated Oxygen

Background: Supersaturated oxygen (SSO₂) delivered into the left anterior descending coronary artery after percutaneous coronary intervention (PCI) for anterior ST-segment elevation myocardial infarction (STEMI) has been shown to reduce infarct size, but its effects on microvascular obstruction (MVO) are unknown. The aim of this study was to compare MVO in patients with anterior STEMI treated with SSO₂ after successful primary PCI from 2 studies (the optimized SSO₂ pilot and IC-HOT) with similar patients from 7 randomized trials who underwent primary PCI without SSO₂ treatment. Methods: A total of 874 patients with anterior STEMI who underwent MVO assessment using cardiac magnetic resonance imaging within 10 days after primary PCI were included, of whom 90 patients (10.3%) were treated with SSO₂. The primary end point was the extent of MVO as a continuous measure in a weighted multivariable model. The secondary end point was the presence of MVO. Results: SSO₂ therapy was independently associated with a lower extent of MVO compared with no SSO₂ therapy (coefficient, −1.35; 95% CI, −2.58 to −0.11; P = .03). SSO₂ therapy was also associated with a borderline lower risk of any MVO (adjusted odds ratio, 0.56; 95% CI, 0.31-1.00; P = .051). Conclusions: In the present individual patient data pooled analysis from 9 studies, SSO₂ therapy was associated with less MVO after successful primary PCI for anterior STEMI.