[Enoximone as an alternative to mechanical circulatory support prior to heart transplantation]

Enoximone, a relatively new type III phosphodiesterase (PDE III) inhibitor with combined positive inotropic and vasodilating properties, was used as a pharmacological bridge to heart transplantation in a patient with severe dilatative cardiomyopathy (ejection fraction 11-13%), who developed cardiogenic shock refractory to conventional therapy with catecholamines and vasodilators. Enoximone led to an 88% increase in cardiac index (from 1.6 to 3.0 l/min.m2). Despite a noticeable rise in heart rate, stroke index increased by 57%. Systemic vascular resistance decreased by 48% without any relevant change in mean arterial pressure. Cardiac filling pressures remained high. Oxygen transport doubled and oxygen extraction ratio decreased by 10%. Apart from a decrease in arterial oxygen tension (from 15.8 to 12.8 kPa [119 to 96 mm Hg]), no other side effects were noted. Withdrawal of catecholamine therapy did not cause any relevant haemodynamic changes. Although complications arose from an uncontrolled septic state, orthotopic heart transplantation was performed with success 74 hours after initiation of enoximone therapy. As the PDE III inhibitor enoximone exerts its potent inotropic and vasodilating effects without requiring adrenergic receptor activation, it may be used as an alternative to mechanical support in patients who develop cardiogenic shock resistant to catecholamines while awaiting heart transplantation.