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Objective: Levosimendan is a calcium-sensitising inotropic agent and a vasodilator used in the treatment of heart failure. Post-cardiotomy cardiac failure is more common in patients with a low preoperative left ventricular ejection fraction (LVEF). We aim at investigating how prophylactic treatment with levosimendan before weaning from cardiopulmonary bypass (CPB) affects postoperative haemodynamics and outcome in patients with low preoperative LVEF., Methods: Patients with a preoperative LVEF < or =30% treated with levosimendan before weaning from CPB were included in the study. Each patient was matched to a control patient with respect to the following criteria: surgical procedure, EuroSCORE, age, gender and the use of intra-aortic balloon pump. We investigated postoperative haemodynamics in the intensive care unit (ICU) at time points: 1, arrival; 2, approximately 7h after arrival; and 3, the first postoperative morning. In addition, mortality was evaluated., Results: Thirty patients treated with levosimendan and 30 matched controls were enrolled in the study. No statistically significant differences in cardiac index (CI) (l min(-1)m(-2)), stroke volume index (SVI) (mlm(-2)), mixed venous O(2)-saturation (SvO(2)) (%) or heart rate (HR) (beats per minute) between the two groups measured at the three time points 1-3 were registered. Mean arterial blood pressure (MAP) (mmHg) was lower in the levosimendan group both at time points 2 (68, range: 65-71 vs 75, range: 72-78; p=0.009) and 3 (72, range: 69-74 vs 78, range: 74-82; p=0.01), despite a higher dose of norepinephrine in the treatment group (p=0.021). A significantly higher number of control patients were treated with classic adrenergic inotropes both in the operating room (p=0.013) and in the ICU (p<0.001). Thirty days mortality was the same in both groups (7%)., Conclusions: Prophylactic infusion of levosimendan initiated before weaning from CPB did not lead to superior haemodynamic parameters (CI, SVI, SvO(2)) compared to controls. Levosimendan reduced MAP and increased the need for norepinephrine postoperatively.

Objective: The time constant of mechanical restitution (T((MRC))), proposed to reflect changes in calcium release and uptake, has been shown to increase in left ventricular (LV) failure, and might have a potential as an index of contractile function. However, in vivo studies of the effect on T((MRC)) of changing loading conditions in the normal and failing heart have not been reported. Consequently, in this study, we tested the hypothesis that the increase in T((MRC)) in vivo is independent of preload and afterload., Methods: Left ventricular pressure-volume loops were assessed at baseline in eight open chest pigs using the combined pressure-volume conductance catheter technique during right atrial pacing at 120b/min. Mechanical restitution curves (MRC) were constructed during four different loading conditions in all eight animals: uninfluenced load, reduced preload (balloon catheter in v. cava inferior), increased afterload (balloon catheter in descending aorta), and increased preload combined with reduced afterload (aortocaval shunting). Acute LV failure was then induced by microembolization through the left main coronary artery, and the experimental protocol was repeated. Contractile response was defined as the maximal first derivative of pressure (dP/dt(max)), and T((MRC)) was calculated using a least square approximation algorithm., Results: Hemodynamic data 30min after microembolization showed decreased mean arterial pressure (98+/-14-67+/-10mmHg, (mean+/-SD) P<0.0001) and dP/dt(max) (1482+/-193-1001+/-125mmHg/s, P=0.001). Stroke volume decreased from 30+/-5 to 20+/-5ml (P<0.0001) compared to baseline, and preload recruitable stroke work decreased from 52+/-7 to 31+/-10mmHg (P=0.002). T((MRC)) increased in all eight animals after induction of LV failure at all loading conditions. There was no difference between the different loading conditions at baseline, nor at LV heart failure, but T((MRC)) increased significantly after the induction of heart failure (ANOVA, two ways)., Conclusions: We have shown that the left ventricular T((MRC)) increases after developed heart failure. The increase in T((MRC)) was independent on loading conditions and thus have a potential for a contractility index.