Potential mechanisms of improved left ventricular function with enoximone in severe congestive heart failure

Enoximone versus epinephrine/nitroglycerin in cardiac low-output states following valve replacement

This prospective, randomized, comparative study was designed to assess the inotropic and vasodilatory effects of the selective phosphosidesterase III inhibitor enoximone compared with standard therapy with epinephrine/nitroglycerin in patients with refractory low output states following cardiac valve replacement. Enoximone possesses inotropic and vasodilatory properties and has proven to be of beneficial effect in patients suffering from severely impaired myocardial function. Six patients in each group received either enoximone bolus-infusion of 0.5 mg/kg over 10 min followed by an infusion of 5 micrograms/kg/min up to 20 micrograms/kg/min or epinephrine and nitroglycerin infusion of 0.05 and 0.5 micrograms/kg/min, respectively, for 4 hours postoperatively. Hemodynamic effects of enoximone and the combination of epinephrine/nitroglycerin were compared. Both treatments led to positive inotropy with a simultaneous decrease in filling pressures and vascular resistances. The results indicate that enoximone in low-output states following cardiac valve replacement was at least equally effective in comparison with standard therapy with epinephrine and nitroglycerin.

Antiischemic and hemodynamic effects of an oral single dose of 150 mg of the phosphodiesterase inhibitor enoximone in patients with coronary artery disease--relation to plasma concentration

The hemodynamic and antiischemic effects of a 150-mg single oral dose of the PDE inhibitor enoximone were correlated with the plasma levels of enoximone and its sulfoxide metabolite. Twenty-one patients with angiographically documented coronary artery disease were investigated by exercise testing 1 and 2 hours after drug administration. The control group consisted of 15 patients with proven coronary artery disease and stable reproducible angina pectoris on exercise. The enoximone group included 14 responders with therapeutic plasma concentrations 2 hours after drug intake and significantly reduced mean pulmonary artery pressures on exercise (from 42.4 +/- 8.6 to 30.9 +/- 11.2 mmHg, p less than 0.05). Compared to basal exercise values, responders showed a reduced ST-segment depression by 1 hour after drug intake (2.1 +/- 1.2 vs. 1.3 +/- 3 mm, p less than 0.05) and minimal values after 2 hours (0.9 +/- 1.0 mm, p less than 0.01) at comparable workloads. There were no significant changes in heart rate, blood pressure, cardiac output, and systemic vascular resistance. No significant improvement in the hemodynamic parameters and ST-segment depression was found in nonresponders with plasma concentrations below 100 ng/ml and 500 mg/ml for enoximone and its metabolite, respectively. In summary, oral administration of enoximone in patients with coronary artery disease led to favorable acute hemodynamic and antiischemic effects at sufficiently high plasma levels of enoximone and its sulfoxide metabolite.

Enoximone treatment of impaired myocardial function during cardiac surgery: combined effects with epinephrine

Enoximone belongs to a new class of noncatecholamine-positive inotropes, which selectively inhibit phosphodiesterase type III and increase cyclic AMP (cAMP). This study was performed in 30 coronary artery surgery patients with impaired myocardial function (ejection fraction [EF] less than 50%). The study's two purposes were to investigate the hemodynamic effects of enoximone, 0.5 mg/kg, administered following induction of anesthesia (phase I), and to assess whether enoximone can potentiate the actions of sympathomimetic agents during weaning from cardiopulmonary bypass (CPB) (phase II). Starting with already reduced hemodynamics, induction of anesthesia led to a further deterioration of blood pressure and cardiac output (CO). Administration of enoximone produced a significant increase in cardiac index (CI) (+47%), whereas pulmonary capillary wedge pressure (PCWP) (-37%), pulmonary artery pressure (PAP) (-17%), and systemic vascular resistance (SVR) (-17%) were significantly reduced. Heart rate (HR) was not increased, and no dysrhythmias occurred during the investigation. The hemodynamic effects were maintained for 30 minutes until the start of the operation. In phase II, where weaning from CPB was not possible without pharmacological support, either enoximone (0.5 mg/kg) + epinephrine (0.1 micrograms/kg/min) or only epinephrine (same dosage) was randomly selected. Weaning was successful in both groups, but the combined therapy produced a larger increase in cl and a more pronounced decrease of the elevated filling pressure (PCWP). PAP was not changed in the combined therapy group, but increased in the patients receiving epinephrine alone. It is concluded that enoximone has beneficial hemodynamic effects in the perioperative period, and that potentiation of the effects of epinephrine in severe heart failure may be one of the drug's most useful features.

RETRACTED: Efficacy of the phosphodiesterase inhibitor enoximone in complicated cardiac surgery

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the request of the editor. In 2018, CHEST published a notice1 that all articles authored by Joachim Boldt be read with caution due to expressions of concern about falsified data. In 2020, CHEST received additional evidence of research misconduct and breaches of scientific integrity that were discovered following an investigation by the author's former institution, the University of Giessen2. In light of this new evidence, this article has been retracted by CHEST. 1. Irwin, R.S., MD, Master FCCP. Notice From the Editor in Chief. CHEST 153(3), p. 767. 2. Mukherjee, J. Statement on the scientific credibility of articles published by Joachim Boldt, formerly professor at Justus Liebig University (JLU), Giessen, Germany. https://ars.els-cdn.com/content/image/1-s2.0-S000709122030163X-mmc3.pdf.

The new phosphodiesterase inhibitor enoximone in patients following cardiac surgery--pharmacokinetics and influence on parameters of coagulation

Enoximone is a selective inhibitor of the phosphodiesterase-III enzyme (PDE-III) and possesses positive inotropic and vasodilatory properties. The PDE-inhibitor amrinone has been associated with adverse effects on coagulation by decreasing platelets. To investigate the influence of enoximone on hemostasis, 18 patients undergoing elective aorto-coronary bypass grafting and receiving enoximone were compared to a control group (n = 18). In addition, the plasma levels of enoximone and its major metabolite (enoximone-sulfoxide) were studied following a single injection (0.5 mg/kg) and during a continuous infusion (5 and 10 micrograms/kg.min) before, during and after extracorporeal circulation (ECC). No difference between study and control groups was found for the parameters of coagulation during the investigation period; in particular there were no differences in platelet count and platelet function (thrombelastography). Following the single bolus, peak plasma levels decreased during ECC to ineffective levels. Continuous infusion, however, maintained effective plasma levels of enoximone; sulfoxide levels were twice as high as enoximone concentrations up until the end of the investigation period. It is concluded that enoximone can be judged to be safe in respect to its effects on coagulation even following ECC and at relatively high doses. The use of continuous infusion results in plasma levels which remain at an effective concentration through to the time that the patient is transferred to the intensive care unit.

Disparity between improvement in left ventricular function and changes in clinical status and exercise capacity during chronic enoximone therapy

Twenty patients with moderately severe congestive heart failure were randomized to chronic enoximone (n = 10) or placebo (n = 10) therapy in a double-blind manner and serially evaluated over a 16-week-period. The purpose of the study was to determine if the addition of standard doses (1 and 2 mg/kg) of this new phosphodiesterase inhibitor to conventional therapy (digitalis and diuretics) would alter the clinical and laboratory course of this patient population. Except for a transient improvement in the quality of life score, none of the symptomatology indicators were significantly affected by enoximone. Similarly, maximal exercise capacity was not altered. Enoximone did elicit a statistically significant augmentation of echocardiographic, radionuclide angiographic, and systolic time interval parameters of left ventricular function. These enoximone-induced effects were accompanied by a significant increase (7% to 11%) in resting heart rate. Enoximone is capable of improving ventricular function when added to digitalis-diuretic therapy in moderately severe congestive heart failure. While individual patients may benefit from enoximone, the ability of standard doses of this agent to improve symptoms and exercise capacity over a 16-week period appears somewhat limited in a moderately severe heart failure population as a whole. Furthermore, a disparity between improvement in ventricular function parameters and changes in clinical status and exercise performance is apparent in this heart failure population.