PURPOSE: The explanation for pleural effusion after cardiac surgery is unclear. The objectives of this study is to describe the patient's characteristics, pleural fluid findings, and pathologic condition in patients with large pleural effusion occurring after coronary artery bypass grafting (CABG).
METHODS: Post CABG patients who underwent therapeutic thoracocenteses and blind pleural biopsy for symptomatic pleural effusion between January 2006 and December 2006 in Chest Diseases Hospital in Kuwait were a prospectively evaluated. Chest radiographs were reviewed and information on pleural fluid findings, biopsy results was obtained.
RESULTS: During the study, 51 patients were identified; 39 men and 12 were women. All patients underwent internal mammary artery grafting. The mean left ventricular ejection fraction was 52%.All patients were dyspneic and had large (>30% of the hemithorax) effusions on chest radiograph. All effusions were persisted after 2 or more thoracocenteses. Bloody pleural effusion occurred early <3 weeks in 34 patients and nonbloody effusion occurred late > 3 weeks in 17 (p=0.01). Patients and pleural fluid characteristics are shown in table 1. Forty biopsy specimens showed pleural thickening characterized by dense fibrous tissues with associated mononuclear cell infiltration while 11 specimens showed only clotted blood. The degree of inflammation and fibrosis correlated with the interval between CABG and pleural surgery. Early post CABG patients with bloody effusions showed more inflammation with abundant lymphocytes. Late cases showed predominantly mature fibrosis (Figure). Recurrence of effusion occurred in 5/34 of patients with bloody effusion and 11/17 of patients with nonbloody effusion (p=0.002). Pleurodesis was necessary in 10 patients.
CONCLUSION: Characteristics of bloody early effusions and nonbloody effusions differ significantly, suggesting a different pathogenesis. Pleural fluid and tissue in early bloody effusion were characterized by lymphocytosis. With time, the inflammatory changes were replaced by fibrosis.
CLINICAL IMPLICATIONS: Persistent post-CABG effusion can occur and in some cases require intervention.
DISCLOSURE: Adel Ayed, No Financial Disclosure Information; No Product/Research Disclosure Information