beneficial effects of a calcium sensitizer [levosimendan], on myocardial contractile performance and systemic hemodynamics after open cardiac surgery to patients with high perioperative risk

ABSTRACT

The increasing number of patients with high preoperative risk referred to cardiac surgery necessitate the common usage of vasodilator and inotropic therapy to decrease the risk of pen-operative complications and mortality. Levosimendan is a calcium sensitizer which increases troponin sensitivity to intracellular calcium without any effect on the myofibrillary ATPase. We tested the possibility of a potential clinical role of levosimendan in cardiac surgical patients with high perioperative risk, compromised left ventricular [LV] function, or with those expected to have difficulties in weaning from cardiopulmonary bypass [CPB]. Thirty-one cardiac patients, 80.6% males and 19.4% females, with a mean ejection fraction of 29.6% underwent open cardiac surgery and were enrolled in this study. In these patients, levosimendan was started at a loading dose 12-24 micro g/Kg infused over 10 minutes, followed by an infusion dose of 0. 05-0.2 micro g/Kg/min. Ventricular performance and systemic hemodynamic changes were estimated for each patient before levosimendan infusion and at 6, 12, 18, and 24 h of the infusion. Significant increase in stroke volume, cardiac output, and cardiac index were observed at all the points.. These changes were reflected positively on the ejection fraction, which was significantly increased after 24h of the levosimendan infusion. Heart rate also increased significantly at 12, 18, and 24h of the infusion while there was no significant change at 6h. The systemic vascular resistance [SVR] was significantly decreased, particularly at 6h but improved at 18, and 24h of the infusion but still remaining significantly lower than the pre-drug value. There was significant decrease in the mean arterial blood pressure [ABP] at 6, 12. 18 and 24h of levosimendan infusion compared with the mean ABP before the infusion. The central venous pressure CVP remained with no significant changes at all time. Both mean pulmonary artery pressure PAP and pulmonary vascular resistance [PVR] were significantly decreased at all time points except for PVR at 6 h which showed no significant decrease. Pulmonary capillary wedge pressure PCWP remained with no significant changes at all time points except during 6 h it showed significant decrease. There was significant decrease in coronary perfusion pressure at all time points. Two patients out of the seven included in this study were on an intra-aortic balloon pump [IABP] pre-operatively and were subsequently weaned successfully from CPB without the balloon pump. the results indicate that levosimendan infusion improves the systemic hemodynamics, amid left ventricular performance in high perioperative risk patients undergoing open cardiac surgery