Prognostic impact of right ventricular dysfunction and hypoxemia in hemodynamically stable acute pulmonary embolism: an individual patient data meta-analysis

Background In hemodynamically stable acute pulmonary embolism (PE), right ventricular dysfunction (RVD) is a key determinant of early risk. Hypoxemia is common at presentation and may reflect impaired pulmonary perfusion or gas exchange abnormalities in acute PE. Whether hypoxemia adds prognostic information beyond RVD remains uncertain. Purpose The aim of this study was to evaluate the independent and combined associations of right ventricular dysfunction (RVD), defined as the presence of at least two abnormal echocardiographic parameters, and hypoxemia with short-term mortality in acute pulmonary embolism. Methods We conducted an individual patient data meta-analysis of observational studies including adults with objectively confirmed acute PE (PROSPERO CRD4202238420). Respiratory insufficiency was defined as oxygen saturation <90% on room air at presentation. The primary outcome was short-term all-cause mortality (in-hospital or ≤30 days); secondary outcome was PE-related mortality. Mixed-effects logistic regression models with random intercept for study were used. Patients were classified into three groups: neither condition, either RVD or hypoxemia alone, and both conditions. An interaction term assessed effect modification. Results The analysis included 2,218 patients from six studies. Overall, 52.6% had neither condition, 36.4% had one, and 11.0% had both[SV1]. Short-term all-cause mortality increased progressively across groups (4.5%, 7.8%, and 11.1%). Compared with patients without either condition, the odds of death were higher in those with one condition (OR 1.88, 95% CI 1.29–2.76) and highest in those with both (OR 2.68, 95% CI 1.64–4.37). In the subset with data on PE-related mortality (n=1,844), mortality rose from 1.9% (reference) to 4.0% (OR 2.39, 95% CI 1.30–4.39) and to 7.2%(OR 4.36, 95% CI 2.17–8.75) in the three groups, respectively. Among haemodynamically stable patients (n=2,152), the associations remained consistent (neither condition=reference, one condition: OR 1.86, 95% CI 1.25–2.77; both: OR 2.25, 95% CI 1.31–3.88). Similar results were observed for PE-related mortality[SV2] . No significant interaction was detected (p=0.43 for all-cause; p=0.67 for PE-related mortality),consistent with additive rather than synergistic effect. Conclusions In hemodynamically stable acute PE, hypoxemia identifies a clinically meaningful subgroup [SV3] at increased short-term risk, particularly when combined with RVD. Mortality exceeded 11% in patients [SV4] presenting with both conditions despite initial stability. Integrating oxygenation status with cardiac imaging markers may refine early risk stratification and support closer monitoring or timely therapeutic escalation.