P221 Causes and outcomes of exudative pleural effusions in congestive cardiac failure (CCF)

Background Up to 20% of pleural effusions in CCF patients could be exudative. Differentiating a transudate from exudate is crucial, in order to rule out malignancy. Diuretics increase fluid protein and can misclassify effusions as exudative. Aim We aimed to study causes and outcomes of exudates secondary to CCF. Methods Retrospective analysis of consecutive patients with suspected CCF (n=204), presenting to pleural clinic at our institution from 24/10/17 – 24/12/18. Electronic patient records from pleural clinics and in-patient episodes were reviewed, up to 12 months after initial presentation. Results 68/204 patients with suspected CCF had pleural effusion aspirated; 41 (20%) were frank exudates(pleural fluid protein > 35 g/dl). 6 aspirates (9%) were marked as traumatic. 50 patients (74%) had unilateral right sided effusion. Histopathology analysis revealed only 24% to be lymphocyte rich. 51 patients (75%) had evidence of cardiac dysfunction on echocardiogram within the last 6 months. 46 patients (68%) were on a minimum dose of 40 mg frusemide at the time of pleural aspiration – no correlation was observed between diuretics dose and fluid protein (CORRELL -0.08). 24/41 exudates (59%) had alternate pathology accounting for high fluid protein including 5 malignant, 8 parapneumonic, 2 recent MI, 4 recent cardiac surgery and 5 with combination of above. 5/17 remaining patients needed a pleural biopsy on clinical grounds which showed fibrinous pleuritis in all five cases. Rest of the patients were observed for a period of 12 months and none turned malignant. Conclusion Most exudative pleural effusions in CCF can be explained by alternative diagnoses, diuretic therapy or traumatic tap. Pleural biopsy in such cases should only be resorted to if suspicion of malignancy is high as most effusions resolve with medical therapy on subsequent follow up.