Nocturnal Hypoxemic Burden Predicts Mortality in Patients Awaiting Heart Transplantation

Risk stratification for patients with end‐stage heart failure (HF) awaiting heart transplantation (HTX) is crucial. Sleep‐disordered breathing (SDB) is a prevalent comorbidity, yet the impact of its resultant hypoxemic burden remains unclear in this population. We investigated the prognostic impact of nocturnal hypoxemic burden in patients with end‐stage HF awaiting HTX. We prospectively enrolled 101 patients with end‐stage HF listed for HTX at a single centre. Baseline polygraphy quantified nocturnal hypoxemic burden (time with SpO2 < 90%; t90). The primary endpoint was a 5‐year composite of all‐cause mortality or left ventricular assist device (LVAD) implantation. Multivariable Cox proportional hazards models were used for adjustment. During 5‐year follow‐up, 24 patients reached the primary endpoint. The primary finding was a significant, dose–response relationship between t90 (analysed as a continuous variable) and the primary endpoint ( p < 0.001). In a multivariable Cox model adjusted for glomerular filtration rate (GFR) and left ventricular ejection fraction (LVEF), each 30‐min increase in t90 was associated with a 29% increase in hazard (Adjusted HR: 1.29, 95% CI: 1.14–1.47, p < 0.001). A t90 of ≥ 180 min was identified as a clinical threshold of high risk, conferring a > 5‐fold increase in hazard (Adjusted HR: 5.18, 95% CI: 1.69–15.81, p = 0.004). The cumulative duration of nocturnal hypoxemic burden is a powerful, independent predictor of death or LVAD implantation in patients with end‐stage HF. Routine assessment of hypoxemic burden should be considered for risk stratification in patients awaiting heart transplantation. Trial Registration: ClinicalTrials.gov : NCT03026634