OC 01.2 - Oxygen vs ambient air in patients with intermediate-risk acute pulmonary embolism: the AIR randomized clinical trial

Saturday, June 24, 2023

13:15 – 13:30 ET

Room: 516

Session Available As: Live-Stream and On-Demand

Presenting Author(s)

David Jimenez, PhD

Professor
Hospital Ramon y Cajal
Madrid, Madrid, Spain

Co-Author(s)

DB

Deisy Barrios

Senior consultant
Hospital Ramon y Cajal
Madrid, Madrid, Spain
DD

Diego Duran

Fellow
Hospital Ramon y Cajal
Madrid, Madrid, Spain
JM

Jorge Moises

Senior consultant
Hospital Universitario Clinic, Barcelona, España
Barcelona, Catalonia, Spain
AR

Ana Retegui

Fellow
Hospital Ramon y Cajal
Madrid, Madrid, Spain
CR

Carmen Rodríguez

Senior consultant
Hospital Ramon y Cajal
Madrid, Madrid, Spain
JL

Jose Luis Lobo

Senior consultant
Hospital Araba
Vitoria, Navarra, Spain
RL

Raquel Lopez-Reyes

Senior consultant
Hospital La Fe
Valencia, Comunidad Valenciana, Spain
LC

Leyre Chasco

Senior consultant
Hospital Galdakao
Bilbao, Pais Vasco, Spain
LJ

Luis Jara-Palomares

Senior consultant
Hospital Universitario Virgen del Rocío, Seville, Spain
Sevilla, Andalucia, Spain
AM

Alfonso Muriel

Expert statistician
Hospital Ramon y Cajal
Madrid, Madrid, Spain
Manuel Monreal, PhD, MD

Senior consultant
Universidad Catolica de Murcia
Barcelona, Catalonia, Spain
Behnood Bikdeli

Associate Physician, Section of Cardiovascular Medicine
Brigham and Women's Hospital, Harvard Medical School
Boston, Massachusetts, United States

Background: In patients with intermediate-risk pulmonary embolism (PE), reversal of hypoxic vasoconstriction could constitute a target for treatment.

Aims: The AIR trial aimed to assess the effect of oxygen in patients with intermediate-risk PE who did not have hypoxemia at baseline.

Methods: AIR randomly assigned non-hypoxemic patients who had stable PE associated with echocardiographic right ventricle (RV) enlargement to receive anticoagulation plus supplemental oxygen at a concentration of 35% (7 l/min) continuously for the first 48 hours versus ambient air plus anticoagulation. The primary outcome was normal RV size on echocardiography measured 48 hours after randomization. Secondary efficacy outcomes were the numerical change in the RV/left ventricle (LV) diameter ratio measured 48 hours and 7 days after randomization, with respect to the baseline ratio measured at inclusion.

Results: The study was prematurely stopped due to the COVID-19 pandemic after recruiting 70 patients (mean [SD] age, 67.3 [16.1] years; 36 women [51.4%]). The intention-to-treat analysis showed normal RV size at 48 hours in 14 (42.4%) of the 33 patients randomly assigned to oxygen, and in 8 (21.6%) of the 37 patients randomly assigned to ambient air (P =0.08). In the oxygen group, the mean RV/LV ratio was reduced from 1.28 +/- 0.28 at baseline to 1.01 +/- 0.16 at 48 hours (P < 0.001); in the ambient air group, mean RV/LV ratios were 1.21 +/- 0.18 and 1.08 +/- 0.19, respectively (P < 0.01). The mean decrease in RV/LV ratio from baseline to 48 hours was 0.28 +/- 0.26 versus 0.12 +/- 0.24 (P =0.02). At 30 days, there was 1 major bleeding (in the ambient air group), no deaths, and no recurrent venous thromboembolism.

Conclusion(s): This trial of patients with non-hypoxemic intermediate-risk PE showed improvement in some efficacy outcomes for supplemental oxygen compared with ambient air and provided support for a definitive clinical outcomes trial.

Learning Objectives:

At the end of this session, participants will be able to identify the pathophysiological mechanisms causing right ventricle dysfunction in patients with acute pulmonary embolism (PE).
At the end of this session, participants will be able to access the main results of the pilot AIR trial evaluating the efficay and safety of supplemental oxygen among non-hypoxemic patients with acute intermediate-risk PE.
At the end of this session, participants will understand the general design of the Registry-based randomized trial to determine the role of Oxygen in acute Pulmonary Embolism (ROPE) study.