[Enoximone--clinical experiences in heart surgery]

In 1991 and 1992, we introduced the new phosphodiesterase-III-inhibitor, enoximone, in the treatment of cardiac low-output-syndromes in the early phase after valve replacement or coronary bypass grafting. We introduced enoximone in cases which met the following criteria: cardiac index < or = 2.4 l/min/m2; systolic arterial pressure < or = 90 mmHg; left ventricular filling pressure > or = 20 mmHg despite the use of dopamine (> or = 12 micrograms/kg/ min); epinephrine (> or = 0.12 microgram/kg/min) and glyceroltrinitrate (1 microgram/kg/min). After clarification of preoperative risk factors and postoperative complications, retrospective evaluation of complete haemodynamic monitoring in patients after valve replacement (14 out of 86) and patients after coronary bypass grafting (22 out of 228) led to the following conclusions. Enoximone is of essential importance for the treatment of cardiac low-output at the end of extracorporeal circulation, particularly in cases complicated by preoperative myocardial deterioration. The use of enoximone is especially effective combined with beta-sympathomimetics as a result of elevation of cAMP-levels in two ways: by stimulation of beta-adrenoceptors directly and by inhibition of phosphodiesterase. Cardiac indices early after bypass, compared with measurements taken before bypass, reveal a clear rise indeed caused by increase in heart rate. Only in patients who underwent coronary bypass grafting did we observe a moderate increase in stroke volume indices. The therapeutic principle of using vasodilators--to lower peripheral resistance for improving stroke volume --appears to be effective immediately after extracorporeal circulation only in part. The vasodilating effect of enoximone has to be constantly compensated for by volume supplementation and alpha-mimetic stimulation, especially after valve replacement surgery. In contrast to this, we continued the application of glyceroltrinitrate in about 25% of the cases. Coronary surgery patients tolerated the vasodilating action particularly well; consequently, despite inotropic stimulation to a high degree, these patients showed no additional signs of ischaemia. Based on our therapeutic measures, the therapy led to very good short-term results. However, this therapeutic regime failed in patients suffering from extended myocardial infarction or irreversible pulmonary hypertension.