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

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.

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.

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.

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