Background: Vascular endothelial growth factor (VEGF) participates in the pathogenesis of exudative pleural effusions (PEs). In the present study, we determined the pleural fluid (PF) and serum VEGF levels in patients with post-coronary artery by-pass grafting (post-CABG) PEs.
Methods: Thirty-eight patients with post-CABG (two with bilateral) PEs were studied. PEs were divided into "early" (occurring earlier than 30 days after surgery) and "late" ones. VEGF levels were measured using ELISA.
Results: (i) Serum and PF VEGF levels did not differ significantly when all the patients (P=0.053) or those with late effusions (P=0.6) were analyzed; serum VEGF levels were significantly elevated in comparison to PF VEGF levels in patients with early (P=0.007) effusions. (ii) Serum VEGF levels were significantly higher in patients with early than in those with late effusions (P=0.033), while PF VEGF levels were not significantly different between the two groups (P=0.77). (iii) PF VEGF levels were higher than corresponding serum levels in 4/24 patients with early and in 10/16 patients with late post-CABG PEs (P=0.006). (iv) In PEs VEGF levels significantly correlated with red blood cells (P=0.015), nucleated cells (P=0.003), protein levels (P=0.002) and lactate dehydrogenase (LDH) levels (P=0.04).
Conclusion: In post-CABG PEs, preferential local production of VEGF in the pleural cavity is most commonly observed a month or later after surgery. The fact that in PEs VEGF levels correlate with markers of pleural inflammation (inflammatory cells and LDH levels) and vascular hyperpermeability (protein levels) suggests that VEGF may be involved in the pathogenesis of post-CABG PEs.