Residual Pleural Thickening Is Related to Vascular Endothelial Growth Factor Levels in Parapneumonic Pleural Effusions

Abstract

Background: Many patients with pneumonia develop pleural effusions. Pleural fluid vascular endothelial growth factor (VEGF) levels are known to be elevated in complicated parapneumonic effusion and seem to play a major role in the fibrotic process in the pleura. Objectives: To test whether VEGF levels in pleural effusions of infectious origin correlate with the residual pleural thickening. Methods: VEGF levels were measured in the pleural fluid of 45 patients with pleural effusion of infectious origin. Patients were reassessed 3 months after hospital discharge and residual pleural thickening (RPT) was recorded using a simple chest radiograph. Results: Pleural fluid VEGF was higher in empyemas compared to simple parapneumonic and complicated parapneumonic effusions. RPT was higher in patients with empyemas compared to simple parapneumonic effusions. Patients with RPT > 2 mm had higher pleural fluid LDH and pleural fluid to serum LDH ratio, lower glucose and pH and higher VEGF levels. However, patients with RPT >= 10 mm differed only in pleural fluid VEGF levels. Pleural fluid VEGF levels correlated to RPT and to pleural fluid pH. VEGF presented moderate performance for the prediction of RPT 3 months after hospital discharge. Its performance was comparable to that of pleural fluid glucose and pH for the development of a radiologically significant RPT > 2 mm, whereas it was the only statistically significant predictor of a clinically significant RPT >= 10 mm. Conclusion: VEGF levels are elevated in complicated parapneumonic effusions and empyemas compared to simple parapneumonic effusions and are a significant predictor for the development of clinically significant RPT. Copyright (C) 2009 S. Karger AG, Basel