Coronary artery bypass graft (CABG) is among the most common cause of pleural effusions (PEs) in the western countries. When they first appear, post-CABG PEs are often bloody and contain high numbers of eosinophils. The aim of the present study was to examine the evolution of the cellular features of post-CABG PEs. We hypothsized that the red blood cells (RBCs) and the percentage of the eosinophils (E%) will decrease while the percentage of the lymphocytes (L%) will increase.
We retrospectively examined 47 patients with unilateral and 2 patients with bilateral post-CABG PEs (totally 49 PEs) who had undergone more than one thoracentesis. Two thoracenteses had been performed in 41 PEs and 3-8 thoracenteses in 8 PEs.
In the group with 2 serial samples, the RBC increased in 9, remained stable in 1 and fell in 31(p<0.05); the E% increased in 17, remained stable in 2 and fell in 10 (p>0.05); the L% increased in 26 remained stable in 2 and fall in 12 (p>0.05). In the group with more than 2 serial samples, a fluctuation for all the examined features was observed. When we compared the features form the first and the last sample, the RBC increased in 1 and fell in 7; the E% increased in 3 and fell in 4; the L% increased in 7 remained stable in 3 and fell in 4.
In symptomatic post-CABG PEs the RBCs tend to fall while the E% and L% tend to rise but there is much inter-individual variation.
In patients with recurring post-CABG PE, pleural fluid values should not be obtained, unless there is a clinical suspicion of other processes.
I.T. Kalomenidis, None.