Hypoxemia after thoracic aortic aneurysm repair

To characterize early postoperative hypoxemia (POH) after proximal aortic aneurysm repair, evaluate its association with outcomes, and determine whether circulatory arrest (CA) contributes to the development of POH.

We performed a single-center retrospective study of 790 adults undergoing proximal aortic aneurysm repair via sternotomy (2012-2024). POH was defined as an arterial oxygen tension/inspired oxygen fraction ratio <300 mm Hg at 6 hours and categorized as no hypoxemia (>300), mild (200-300), or moderate/severe (<200). Baseline and operative characteristics were balanced using 3-way inverse probability of treatment weighting. The primary end point was composite respiratory morbidity (including prolonged ventilation and supplemental oxygen use, reintubation, and postoperative pneumonia); secondary end points included 7-year mortality. Weighted regression evaluated factors associated with POH, including CA exposure.

POH occurred in 433 patients (54.8%): 266 (33.7%) mild and 167 (21.1%) moderate/severe; 357 (45.2%) had no hypoxemia. After inverse probability of treatment weighting was performed, the severity of hypoxemia was associated with composite respiratory morbidity (43.8% none vs 50.6% mild vs 57.0% moderate/severe; P = .030). However, hypoxemia was not associated with 7-year mortality (hazard ratio, 0.77; 95% CI, 0.38-1.37; P = .321). Use of CA was not associated with moderate/severe POH (odds ratio, 0.96; CI, 0.60-1.53; P = .864).

Early POH is common after proximal aneurysm repair and is associated with increased respiratory morbidity but not mortality. CA does not appear to contribute to moderate/severe POH.