Clinical Relevance of Pleural Effusion in Patients with Pulmonary Embolism

Data regarding pleural effusion due to pulmonary embolism (PE) are limited.

The aim of this study was to investigate the clinical characteristics of PE patients with pleural effusion caused by PE.

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.

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.

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.