The use of supersaturated oxygen therapy in patients with late-presentation anterior ST-segment elevation myocardial...

Patients with late-presentation anterior ST-elevation myocardial infarction (STEMI) are at increased risk of heart failure and mortality due to greater infarct size and microvascular injury including microvascular obstruction (MVO) and intramyocardial hemorrhage (IMH). Apart from primary percutaneous coronary intervention (PCI), no additional therapies are available for this high-risk group. Supersaturated oxygen therapy (SSO₂) is utilized for anterior STEMIs with ischemic times under 6 h and may reduce infarct size. We investigated if SSO₂ therapy may provide a clinical benefit for late-presentation anterior STEMI patients.

SSO₂ therapy was administered to 19 late-presentation anterior STEMI patients (12 males (M), 7 females (F); 60 yr.) for 60-min following primary PCI. Patients underwent cardiac MRI (CMR) prior to discharge for evaluation of infarct size, MVO, and IMH. Results were compared to a control group of 31 late-presentation anterior STEMI patients (19 M, 12F; 59 yr.) who received PCI and CMR but not SSO₂.

The left anterior descending artery (LAD) was completely occluded in 89 % of SSO₂ patients and 77 % of control patients prior to PCI. Final TIMI 3 flow was achieved in 84 % of all patients. Ejection fraction at baseline as well as infarct size, were similar between the two groups. Significantly fewer SSO₂ patients had MVO (75 % vs 100 %, p = 0.01) and residual ST-segment elevation following PCI was significantly less in the SSO2 group suggestive of improved microvascular perfusion. Mortality was significantly reduced in the SSO2 group following STEMI compared to control patients (0 % vs 23 %, p = 0.03).

SSO₂ can be safely delivered to late-presentation anterior STEMI patients and results in less MVO and less adverse events including all-cause mortality. SSO₂ therapy may represent a new treatment for this high-risk patient group.