Preoperative usages of levosimendan in patients undergoing coronary artery bypass grafting

Levosimendan (LS) is a new inotropic drug which belongs to the group of drugs known as calcium sensitizers. It is different from other inotropic agents by its inotropic and vasodilatory actions without an increase in myocardial oxygen consumption and considered as a good choice in high-risk patients undergoing cardiac surgery. We aimed to investigate the proper time of the administration and the effect of prophylactic usage of LS in patients with low left ventricular ejection fraction (LVEF) undergoing coronary artery bypass grafting (CABG).

Forty patients who underwent isolated CABG with LVEF) less than 30% were evaluated retrospectively. Patients were divided into 3 groups according to the induction time of LS during different phases of the operation and compared to a non-LS control group. LS infusion (0.2 μg/kg/min) was applied 12 hours before the operation in Group 1 (G1) (n=10), after the induction of anaesthesia in Group 2 (G2) (n=10) and during the pump removal period in Group 3 (G3) (n=10) and non-LS control group 4 (G4) (n=10). Demographic data, operative characteristics, hemodynamic parameters and serum lactate, troponin, creatinine levels were compared between groups before and after LS treatment during pre and postoperative period. Data were evaluated by Fisher exact, Kruskal-Wallis, Mann-Whitney U, Chi-square and Wilcoxon rank tests.

We found that the duration of tracheal intubation, the intensive care unit stay and the hospital stay were significantly decreased in G1 and G2 when compared to the patients in G3 and G4. During postoperative period, in G1 and G2 one (10%) patient from each required intraaortic balloon pump (IABP), while in G3 two (20%) patients and in G4 five (50%) patients required IABP. Cardiac index (CI) was significantly increased in all groups from baseline to intensive care unit (ICU)1h and ICU24h. When groups compared each other significant increase was found in G1-G4 (p=0.001) and G2-G4 (p=0.007) at ICU1h. There was a significant increase in % EF especially in G1-G4 (p=0.011) and G2-G4 (p=0.007) at ICU1h. Systemic vascular resistance index significantly decreased in G1 and G2 in comparison to G3 and G4. However there was no significant decrease in pulmonary capillary wedge pressure of all 4 groups before and after LS. There was a significant decrease in mean pulmonary arterial pressure in G1 and G2 according to G4. Compared with the other groups preoperatively LS-treated patients (G1 and G2) had lower postoperative troponin I, serum lactate and creatinine concentrations.

Our study shows that the elective preoperative initiation of LS especially 12 hours before the operation onset is associated with better improvement on cardiac functions as well as with lower mortality and complication rates, lower use of additional inotropic and vasopressor drugs, less need for intra-aortic balloon pump support and shorter length of stay in the ICU in patients with high perioperative risk or compromised left ventricular function. As a result, patients who received an infusion of LS 12 hours before surgery showed an evidence of less myocardial damage which suggested the preconditioning effect of the drug.