Hypoxia as an independent predictor of adverse outcomes in pulmonary embolism

Background The purpose of this study was to investigate the correlation between the computed tomography pulmonary artery obstruction index and parameters of functional lung impairment in acute pulmonary embolism, and establish the value of these parameters in prognosticating right ventricular dysfunction and 30-day mortality. Methods This study included 322 consecutive patients (mean age 45.6 ± 13.2 years, 46.9% male) with acute pulmonary embolism, free of other cardiopulmonary disease, who underwent computed tomography pulmonary angiography. Correlations of arterial CO₂, O₂, and alveolar-arterial oxygen gradient with the computed tomography pulmonary artery obstruction index, measured using the Qanadli score, were analyzed. Logistic regression was used to identify independent predictors of right ventricular dysfunction and 30-day mortality. Results Of the 322 patients, 196 (60.9%) had right ventricular dysfunction, and 58 (18.0%) died within 30 days. The pulmonary artery obstruction index had a significant correlation with partial pressures of arterial O₂ ( r = -0.887, p < 0.001) and CO₂ ( r = -0.618, p = 0.019) and alveolar-arterial oxygen gradient ( r = +0.874, p < 0.001). Arterial O₂ pressure had a good predictive accuracy and discriminative power for both right ventricular dysfunction (sensitivity 80.6%, specificity 85.1%, area under the curve 0.91) and 30-day mortality (sensitivity 77.8%, specificity 82.0%, area under the curve 0.89). Conclusions In patients with acute pulmonary embolism, free of other cardiopulmonary disease, parameters of functional impairment have a strong correlation with computed tomography pulmonary artery obstruction index. Hypoxia is an independent predictor of both right ventricular dysfunction and 30-day mortality in these patients.