Clinical Relevance of Pleural Effusion in Patients with Pulmonary Embolism.

BACKGROUND: Data regarding pleural effusion due to pulmonary embolism (PE) are limited. OBJECTIVES: The aim of this study was to investigate the clinical characteristics of PE patients with pleural effusion caused by PE. METHODS: Patients with PE were retrospectively analyzed and divided into 2 groups based on computed tomography: a group with pleural effusion due to PE (effusion group) and a group without pleural effusion (control group). Clinical characteristics were compared between the 2 groups. RESULTS: The study population consisted of the effusion group (n = 127) and the control group (n = 651). Serum C-reactive protein (CRP) level was significantly higher in the effusion group than in the control group. The percentages of high-risk Simplified PE Severity Index (57 vs. 47%, p = 0.008), central PE (84 vs. 73%, p = 0.013), right ventricular dilation (45 vs. 36%, p = 0.053), and pulmonary infarction (40 vs. 8%, p < 0.001) were higher in the effusion group than in the control group. Multivariate analysis demonstrated that pulmonary infarction (odds ratio [OR] 6.20, 95% confidence interval [CI] 3.49-10.91, p < 0.001) and CRP level (OR 1.05, 95% CI 1.101-1.09, p = 0.023) were independent predictors of pleural effusion due to PE. The presence of pleural effusion was not a predictor of short-term outcomes or length of hospital stay. CONCLUSIONS: Patients with more severe PE are likely to have pleural effusion caused by PE. However, pleural effusion was not a proven predictor of short-term outcome or length of hospital stay. Pulmonary infarction and CRP levels were independent risk factors for the development of pleural effusion.