André Y. Denault François Haddad , Yoan Lamarche Anne Q.N. Nguyen, France Varin, Sylvie Levesque, Yanfen Shi, Louis P.Perrault, Jean-Claude Tardif and Jean Lambert
Background: Pulmonary hypertension is a major cause of mortality and morbidity in patients undergoing valvular and complex heart surgery. Inhaled milrinone has been used for the treatment of pulmonary hypertension, but its safety and effects compared with a placebo on hemodynamics and ventricular function have not been studied in patients undergoing high-risk valvular surgery. Methods: Twenty-one high-risk cardiac surgical patients with preoperative pulmonary hypertension were randomized in a double-blind study to receive inhaled milrinone or placebo. The inhalation occurred after the induction of anesthesia and before the surgical incision and cardiopulmonary bypass. The effects on ventricular function were evaluated by means of pulmonary artery catheterization and transesophageal echocardiography. The primary outcome variable was the systemic mean arterial pressure. Results: There were 8 men and 13 women (mean age 71 ± 6 years) with a mean Parsonnet score of 32 ± 9 who underwent a total of 17 complex procedures and 6 reoperations. There were no significant changes in mean arterial pressure throughout the study. A reduction in pulmonary vascular resistance (p = 0.0458) was observed in the inhaled milrinone group, but the change in mean pulmonary artery pressure was not significant (p = 0.1655). Right ventricular end-diastolic area (p = 0.0363) and right atrial transverse diameter (p < 0.0001) increased in the control group, but not with inhaled milrinone. No significant side effects occurred in the inhaled milrinone group. Conclusion: In this high-risk cardiac surgery cohort, the use of inhaled milrinone was not associated with systemic hypotension but with a reduced pulmonary vascular resistance and prevention of the increase in right-sided cavity dimensions.