Background: Pleural effusion is a common finding after coronary artery bypass surgery (CABG). We sought to determine the incidence and patient characteristics predictive of its appearance, in addition to the effect of post-operative treatment with enoxaparin.
Methods: We retrospectively examined 893 patients undergoing CABG: 520 consecutive patients did not receive enoxaparin, and 373 patients received it. All early (up to 10 days) peri-operative chest radiograms were examined and graded by the amount of pleural effusion: (i) small--obliteration of the costophrenic angle; (ii) moderate-- < 50% of lung field; (iii) large-- > 50% of lung field. Patient characteristics as well as operative and post-operative parameters were analyzed in order to identify predictors for pleural effusion.
Results: Pleural effusion was small in 415 patients (46%), moderate in 346 (39%) and large in 132 (15%). Older age, female gender and congestive heart failure were found to be predictors for pleural effusion by multi-variate analysis (p <0.05). Routine use of enoxaparin was not found to be associated with pleural effusion after CABG.
Conclusions: Over 50% of patients will develop a significant pleural effusion following CABG. Prophylactic treatment with enoxaparin does not increase the risk for pleural effusion.