Comparative Study of Vascular Endothelial Growth Factor in Exudative and Transudative Pleural Effusion.

Background: Increased vascular permeability is one of the main mechanisms in the production of pleural effusion (PE) and vascular endothelial growth factor (VEGF) has a significant role in its pathogenesis. This study aimed to compare pleural levels of VEGF in transudative and exudative PEs besides the other pleural markers.

Materials and methods: In this prospective cross-sectional study, 80 patients with PE were divided into 4 groups as transudative (N=15), parapneumonic (N=15), tuberculosis (N=25), and malignant (N=25) PE. Biochemical tests measured the pleural protein, LDH, cholesterol, glucose, polymorphonuclear cell (PMN), and lymphocyte. ELISA measured the pleural VEGF level.

Results: Out of 80 patients, 51 were male, and the total mean age was 55.34±18.53. There were significant differences in pleural VEGF between exudative and transudative effusion (P<0.001) and between malignant and benign effusion (P=0.014). The highest mean difference in pleural VEGF levels was seen in the comparison of transudative and malignant groups (Mean difference=-136.56; P<0.002). The VEGF level in 3 groups was not significantly different; transudative vs tuberculous, parapneumonic vs tuberculous, and parapneumonic vs malignant. Furthermore, VEGF higher than 73.09 pg/ml had a 64% sensitivity and 82% specificity for the diagnosis of malignancy. Among pleural markers (VEGF, protein, LDH, and glucose), VEGF had the highest area under curve (AUC=0.734). Moreover, pleural protein, LDH, and glucose levels significantly correlated with pleural VEGF; however, pleural cholesterol, PMN, and lymphocyte were not correlated.

Conclusion: VEGF is assumed as an important factor in the pathogenesis of exudative PE, especially malignant effusion. It can distinguish between lymphocytic exudative PEs.