Haemodynamic effects of levosimendan following cardiac surgery

Introduction

Myocardial contractile function following cardiac surgery often requires inotropic support. Traditionally, phosphodiesterase inhibitors and catecholamines are used [1, 2]. Levosimendan is a novel inotropic agent–calcium sensitizer that enhances myocardial contractility without increasing intracellular calcium and myocardial oxygen demand [3]. The aim of our study was to evaluate circulation following levosimendan infusion, to find out the efficiency of tissue oxygen supply and to evaluate other inotrope dosage rates during levosimendan infusion.

Methods

Thirteen patients with acute heart failure following elective cardiac surgery under cardiopulmonary bypass treated with levosimendan and other inotropes were enrolled. Haemodynamic parameters (mean arterial pressure, central venous pressure, mean pulmonary artery pressure, cardiac index), PaO₂, SvO₂, plasma lactate, cardiac troponin I and other inotropes rates were obtained at baseline, 30 minutes, 1 hour, 6 hours and 24 hours after the start of levosimendan infusion. Levosimendan was administered at a rate of 0.1 μg/kg/minute (no bolus) with a total 24-hour dose of 12.5 mg for each patient. Other inotropic agents used were epinephrine (range 0.03 to 0.15 μg/kg/min), norepinephrine (range 0.03 to 0.18 μg/kg/min), dobutamine (range 3.5 to 7 μg/kg/min) and corotrope (range 0.3 to 0.6 μg/kg/min).

Results

Thirteen patients (nine female, four male) were investigated. Forty-six per cent of patients had III to IV (New York Heart Association) stage of congestive heart failure (ejection fraction <40%). Six patients died within 24 hours and were excluded. Maximal changes occurred 24 hours after levosimendan infusion. Mean arterial pressure increased, while the mean pulmonary artery pressure and central venous pressure decreased. The cardiac index did not change considerably. Oxidative stress markers improved. Mean infusion rates of epinephrine, dobutamine and corotrope decreased, while the norepinephrine mean rate did not change.

Conclusion

Levosimendan improves circulation by means of its positive inotropic effect, increases mean arterial pressure, and decreases pulmonary pressure. Levosimendan could be a drug of choice in myocardial hypoxia, probably combined with right heart failure.