ENALAPRILAT DECREASES PLASMA ENDOTHELIN AND ATRIAL-NATRIURETIC-PEPTIDE LEVELS AND PRELOAD IN PATIENTS WITH LEFT-VENTRICULAR DYSFUNCTION AFTER CARDIAC-SURGERY

Objective: To study the acute effects of angiotensin-converting Enzyme inhibition by intravenous enalaprilat infusion in patients with left ventricular dysfunction after cardiac surgery. Design: Prospective, co nsecutive sample, before-after trial. Setting: Surgical intensive care unit in a tertiary care university hospital. Participants: Eight pati ents with left ventricular dysfunction after cardiac surgery. Patients were defined as having left ventricular dysfunction if the pulmonary capillary wedge pressure persisted above 18 mmHg in spite of conventio nal vasoactive medication (inotropic or vasodilating and diuretic drug s) and intermittent mandatory ventilation during the first postoperati ve week. Interventions: Enalaprilat was infused initially at 1 mg/hour . The rate was doubled every 30 minutes until pulmonary capillary wedg e pressure decreased at least 20% or until a maximum total dose of 10 mg was achieved. Measurements and Results: Central hemodynamics, syste mic oxygenation, and hormonal regulation of circulation (plasma renin activity, plasma endothelin, atrial natriuretic peptide, norepinephrin e, epinephrine, and vasopressin concentrations, serum angiotensin-conv erting enzyme activity, and serum levels of aldosterone) were assessed at baseline before enalaprilat infusion, and repeatedly over 2 hours after the infusion. Enalaprilat infusion (median hose, 2.0 mg; infusio n time, 48 minutes) caused a significant decrease in pulmonary capilla ry wedge pressure (p = 0.004), lasting until the end of the 2 hours' f ollow-up. This coincided with inhibition of serum angiotensin-converti ng enzyme activity (p < 0.001), an increase in plasma renin activity ( p = 0.022), and decreases in plasma endothelin (p = 0.035), atrial nat riuretic peptide (p = 0.005), and serum aldosterone (p = 0.001) concen trations. Cardiac output, venous admixture, and oxygen delivery and co nsumption remained unchanged. Conclusions: Adding enalaprilat to conve ntional therapy makes it possible to unload the left ventricle and to relieve overt neurohormonal activation temporarily while maintaining c ardiac function and systemic oxygenation. Copyright (C) 1997 by W.B. S aunders Company.