Background: The incidence of asymptomatic pericardial effusion is high after cardiac surgery. Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely prescribed in this setting, but no study has assessed their efficacy.
Objective: To assess whether the NSAID diclofenac is effective in reducing postoperative pericardial effusion volume.
Design: Multicenter randomized, double-blind, placebo-controlled study. (Clinical trials.gov registration number: NCT00247052)
Setting: 5 postoperative cardiac rehabilitation centers.
Patients: 196 patients at high risk for tamponade because of moderate to large persistent pericardial effusion (grade 2, 3, or 4 on a scale of 0 to 4, as measured by echocardiography) more than 7 days after cardiac surgery.
Intervention: Random assignment at each site in blocks of 4 to diclofenac, 50 mg, or placebo twice daily for 14 days.
Measurements: The main end point was change in effusion grade after 14 days of treatment. Secondary end points included frequency of late cardiac tamponade.
Results: The initial mean pericardial effusion grade was 2.58 (SD, 0.73) for the placebo group and 2.75 (SD, 0.81) for the diclofenac group. The 2 groups showed similar mean decreases from baseline after treatment (-1.08 grades [SD, 1.20] for the placebo group vs. -1.36 (SD, 1.25) for the diclofenac group). The mean difference between groups was -0.28 grade (95% CI, -0.63 to 0.06 grade; P = 0.105). Eleven cases of late cardiac tamponade occurred in the placebo group and 9 in the diclofenac group (P = 0.64). These differences persisted after adjustment for grade of pericardial effusion at baseline, treatment site, and type of surgery.
Limitation: The sample was not large enough to find small beneficial effects of diclofenac or assess the cardiovascular tolerance of diclofenac.
Conclusion: In patients with pericardial effusion after cardiac surgery, diclofenac neither reduced the size of the effusions nor prevented late cardiac tamponade.
Primary funding source: French Society of Cardiology.