Hemodynamic, antiischemic, and neurohumoral effects of enoximone in patients with coronary artery disease.

To evaluate the risk of ischemia in 17 patients with significant coronary artery disease, the influence of enoximone was analyzed under the following conditions: (1) at rest (RC) and during exercise (ExC) under control conditions and (2) at rest (RE) and during exercise (ExE) after administration of enoximone (0.75 mg/kg, intravenously). During ExC all patients had ischemia (angina, and ST segment alterations); metabolic markers of ischemia (MMI) increased, as did the mean pulmonary artery pressure, from 19 to 41 mm Hg. However, during ExE ischemia was abolished (no angina, decrease in mean pulmonary artery pressure to 24 mm Hg, and improvement in MMI) and there was some improvement in left ventricular pump function, whereas pre- and afterload decreased (pulmonary artery pressure by 40%, systemic vascular resistance by 10%), and heart rate, arterial pressure, and myocardial oxygen consumption (MVO2) were all unchanged (p greater than 0.05). Comparative hemodynamics at RE vs RC showed a decrease in pulmonary artery pressure (by 25%) and pulmonary vascular resistance (by 19%) and an increase in heart rate (by 11%), whereas arterial pressure and MVO2 were unchanged (p greater than 0.05). Enoximone did not induce changes in plasma catecholamine, prostaglandin, or thromboxane levels (p greater than 0.05), whereas the atrial natriuretic factor decreased (by 15%), probably because of unloading of the atria during exercise. We concluded that enoximone induces beneficial hemodynamic effects in coronary artery disease without causing ischemia, probably by enhancing myocardial contractility, vasodilation, and improved diastolic properties.