The Effect of Inhaled Milrinone Versus Inhaled Levosimendan in Pulmonary Hypertension Patients Undergoing Mitral Valve Surgery - A Pilot Randomized Double-Blind Study.

OBJECTIVE: To compare the effects of inhaled milrinone and levosimendan on pulmonary and systemic hemodynamics in patients with pulmonary hypertension.

DESIGN: Prospective, double-blind, randomized controlled study.

SETTING: Tertiary care cardiac institute with 650 beds.

PARTICIPANTS: The study comprised 150 adult patients with pulmonary hypertension undergoing mitral valve surgery.

INTERVENTIONS: Patients were assigned randomly into 1 of the following 3 groups: milrinone (M), levosimendan (L), or control (C); n = 50 per group. In group M, inhaled milrinone (50 µg/kg); in group L, inhaled levosimendan (24 µg/kg); and in group C, normal saline was administered when the patient arrived in the recovery room. Pre-inhalation and post-inhalation hemodynamics (mean arterial pressure [MAP], pulse rate, and systemic vascular resistance [SVR]) were noted until 24 hours of inhalation of the drug. The change in pulmonary artery pressures (pulmonary artery systolic pressure [PASP] and mean pulmonary artery pressure [MPAP]) and the duration for which they remained decreased compared with the control group, were noted.

MEASUREMENTS AND MAIN RESULTS: MAP, pulse rate, and SVR were comparable in the 3 groups at various time intervals. PASP and MPAP decreased comparably after inhalation of levosimendan and milrinone. However, they reached levels near the control group values after 2.5 to 3 hours in group L and after 0.5 hours in group M.

CONCLUSIONS: Because inhaled levosimendan causes a decrease in PASP and MPAP without causing a decrease in SVR and MAP, the authors conclude that inhaled levosimendan is a selective pulmonary vasodilator. It is as effective as milrinone in reducing pulmonary artery pressures. In addition, it has advantage over inhaled milrinone because it is has a longer duration of action.