Meta-analysis of randomized trials of effect of milrinone on mortality in cardiac surgery: an update

OBJECTIVE: The long-term use of milrinone is associated with increased mortality in chronic heart failure. A recent meta-analysis suggested that it might increase mortality in patients undergoing cardiac surgery. The authors conducted an updated meta-analysis of randomized trials in patients undergoing cardiac surgery to determine if milrinone impacted survival. DESIGN: A meta-analysis. SETTING: Hospitals. PARTICIPANTS: One thousand thirty-seven patients from 20 randomized trials. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Biomed, Central, PubMed, EMBASE, the Cochrane central register of clinical trials, and conference proceedings were searched for randomized trials that compared milrinone versus placebo or any other control in adult and pediatric patients undergoing cardiac surgery. Authors of trials that did not include mortality data were contacted. Only trials for which mortality data were available were included. Overall analysis showed no difference in mortality between patients receiving milrinone versus control (12/554 [2.2%] in the milrinone group v 10/483 [2.1%] in the control arm; relative risk [RR] = 1.15; 95% confidence interval [CI], 0.55-2.43; p = 0.7) or in analysis restricted to adults (11/364 [3%] in the milrinone group v 9/371 [2.4%] in the control arm; RR = 1.17; 95% CI, 0.54-2.53; p = 0.7). Sensitivity analyses in trials with a low risk of bias showed a trend toward an increase in mortality with milrinone (8/153 [5.2%] in the milrinone arm v 2/152 [1.3%] in the control arm; RR = 2.71; 95% CI, 0.82-9; p for effect = 0.10). CONCLUSIONS: Despite theoretic concerns for increased mortality with intravenous milrinone in patients undergoing cardiac surgery, the authors were unable to confirm an adverse effect on survival. However, sensitivity analysis of high-quality trials showed a trend toward increased mortality with milrinone.