Long-Term Effects of Oxygen Therapy on Death or Hospitalization for Heart Failure in Patients With Suspected Acute Myocardial Infarction
Authors: Jernberg Tomas , Lindahl Bertil , Alfredsson Joakim , Berglund Ellinor , Bergström Olle , Engström Anders , Erlinge David , Herlitz Johan , Jumatate Raluca , Kellerth Thomas , Lauermann Jörg , Lindmark Krister , Lingman Markus , Ljung Lina , Nilsson Carina , Omerovic Elmir , Pernow John , Ravn-Fischer Annica , Sparv David , Yndigegn Troels , Östlund Ollie , James Stefan K. , Hofmann Robin ,   For the DETO2X-SWEDEHEART Investigators, Linder Rickard , Ekström Mattias , Forsman Lena , Angerås Oskar , Hornestam Björn , Kastberg Robert , Haugen Espen , Millbourn Anna , Carlsson Jörg , Haaga Urban , Mellbin Linda , Verouhis Dinos , Kjellberg Fredrik , Malmqvist Lennart , Eriksson Gull-Britt , Nilsson Lennart , Swahn Eva , Venetsanos Dimitrios , Pettersson Tommy , Pourbazargan Melvin , Serrander Martin , Karlsson Jan-Erik , Barmano Neshro , Risenfors Martin , Peterson Magnus , Wallström Ylwa , Ekelund Ulf , Erlandsson Marianne , Witt Nils , Frick Mats , Svensson Leif , Arefalk Gabriel , Lagerqvist Bo , Digerfeldt Christofer , Byström Björn 
Published: December 2018

Background:
In the DETO2X-AMI trial (Determination of the Role of Oxygen in Suspected Acute Myocardial Infarction), we compared supplemental oxygen with ambient air in normoxemic patients presenting with suspected myocardial infarction and found no significant survival benefit at 1 year. However, important secondary end points were not yet available. We now report the prespecified secondary end points cardiovascular death and the composite of all-cause death and hospitalization for heart failure.

Methods:
In this pragmatic, registry-based randomized clinical trial, we used a nationwide quality registry for coronary care for trial procedures and evaluated end points through the Swedish population registry (mortality), the Swedish inpatient registry (heart failure), and cause of death registry (cardiovascular death). Patients with suspected acute myocardial infarction and oxygen saturation of ≥90% were randomly assigned to receive either supplemental oxygen at 6 L/min for 6 to 12 hours delivered by open face mask or ambient air.

Results:

A total of 6629 patients were enrolled. Acute heart failure treatment, left ventricular systolic function assessed by echocardiography, and infarct size measured by high-sensitive cardiac troponin T were similar in the 2 groups during the hospitalization period. All-cause death or hospitalization for heart failure within 1 year after randomization occurred in 8.0% of patients assigned to oxygen and in 7.9% of patients assigned to ambient air (hazard ratio, 0.99; 95% CI, 0.84–1.18;
P
=0.92). During long-term follow-up (median [range], 2.1 [1.0–3.7] years), the composite end point occurred in 11.2% of patients assigned to oxygen and in 10.8% of patients assigned to ambient air (hazard ratio, 1.02; 95% CI, 0.88–1.17;
P
=0.84), and cardiovascular death occurred in 5.2% of patients assigned to oxygen and in 4.8% assigned to ambient air (hazard ratio, 1.07; 95% CI, 0.87–1.33;
P
=0.52). The results were consistent across all predefined subgroups.

Conclusions:
Routine use of supplemental oxygen in normoxemic patients with suspected myocardial infarction was not found to reduce the composite of all-cause mortality and hospitalization for heart failure, or cardiovascular death within 1 year or during long-term follow-up.

Clinical Trial Registration:

URL:
https://www.clinicaltrials.gov
. Unique identifier: NCT01787110.