[Hemodynamic effects of the new phosphodiesterase inhibitor enoximone in heart surgery patients].

The new phosphodiesterase-III inhibitor (PDI) enoximone is a non-catecholamine, non-glycoside cardiotonic agent with concomitant vasodilating properties. It has proved beneficial in patients with severe chronic heart failure. The influence of enoximone i.v. on hemodynamics was investigated during cardiac surgery under various conditions. METHODS. A randomized series of 60 patients undergoing elective aorto-coronary bypass grafting were studied. The hemodynamic effects of 0.5 mg/kg enoximone given i.v. as a bolus (30 s) were investigated before anesthesia (n = 10), during anesthesia (n = 10), and during extracorporeal circulation (ECC, n = 10) and compared with those observed in corresponding control groups (n = 10 in each control) of patients who had received saline solution as placebo. Anesthesia was maintained with weight-dependent dosages of fentanyl, midazolam and pancuronium bromide. All patients were invasively monitored by means of a pulmonary artery catheter. Additionally, left ventricular pressure (LVP), left ventricular end-diastolic pressure (LVEDP) and dp/dtmax were measured before the initiation of ECC. During ECC direct vascular effects were investigated with measurement of perfusion pressure and the volume of the oxygenator. RESULTS. Before the induction of anesthesia no significant change in MAP and HR could be observed, whereas CI increased (+20%) and TSR decreased (-24%) significantly. During anesthesia, the injection of enoximone was followed by a significant decrease in MAP only in the 1st min (-17%); baseline level was reached again after 6 min; and HR was slightly increased (+8%). TSR (-31%) and LVEDP (-38%) decreased, whereas CI (+17%) and dp/dtmax (+45%) were increased significantly. During ECC perfusion pressure (-37%) and the volume of the oxygenator (-17%) were significantly decreased, demonstrating direct vasodilating effects on both the arteries and the vein. CONCLUSION. Arterial and venous vasodilation with an increase in myocardial performance (dp/dtmax) resulting in an increase in CI were the predominant hemodynamic effects of enoximone i.v. No arrhythmogenic effects or interactions with the anesthetics used were observed in this study.