Clinical relevance of bilateral pleural effusion in patients with acute pulmonary embolism

Background: The clinical relevance of bilateral pleural effusion (BPE) in patients with acute pulmonary embolism (PE) is unclear. Aims: To describe characteristics of patients with acute PE that present with BPE. Methods: Patients with acute PE were retrospectively analysed and divided into three groups: without pleural effusion, unilateral pleural effusion and bilateral effusion. Clinical, laboratory and radiological characteristics were compared between the three groups. Results: The study population (n = 343) consisted of unilateral effusion group (n = 83), BPE group (n = 94) and without effusion group (n = 166). Several variables were noted in higher proportion (%), in the BPE group in comparison to both the unilateral effusion and without effusion groups: heart failure (17.0 vs 7.2 vs 6.7, P = 0.017), hypoalbuminaemia (59.3 vs 39.5 vs 25.6, P ˂ 0.001), PE occurrence in-hospital setting (51 vs 25.6 vs 15.1, P ˂ 0.001), major operation (31 vs 19.2 vs 15.2, P = 0.01) and mechanical ventilation (13.0 vs 4.9 vs 4.2, P = 0.019). Norton scale scores were found to be lower among patients with BPE in comparison to both patients with unilateral and without pleural effusion (15.55 vs 16.92 vs 17.36, P = 0.006). After adjusting confounding variables, patients with BPE have lower probability for in-hospital survival in comparison to both patients with unilateral pleural effusion (odds ratio = 0.30, 95% confidence interval 0.12–0.79), and patients without pleural effusion (odds ratio = 0.26, 95% confidence interval 0.11–0.61). Conclusions: BPE in patients with acute PE may have significant clinical implications. It may signify serious underlying comorbidities which contribute to higher in-hospital mortality in comparison to both patients with unilateral pleural effusion and patients without pleural effusion.