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.


METHODS
Prospective, consecutive sample, before-after trial.


METHODS
Surgical intensive care unit in a tertiary care university hospital.


METHODS
Eight patients 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 conventional vasoactive medication (inotropic or vasodilating and diuretic drugs) and intermittent mandatory ventilation during the first postoperative week.


METHODS
Enalaprilat was infused initially at 1 mg/ hour. The rate was doubled every 30 minutes until pulmonary capillary wedge pressure decreased at least 20% or until a maximum total dose of 10 mg was achieved.


RESULTS
Central hemodynamics, systemic oxygenation, and hormonal regulation of circulation (plasma renin activity, plasma endothelin, atrial natriuretic peptide, norepinephrine, epinephrine, and vasopressin concentrations, serum angiotensin-converting 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 dose, 2.0 mg; infusion time, 48 minutes) caused a significant decrease in pulmonary capillary wedge pressure (p = 0.004), lasting until the end of the 2 hours' follow-up. This coincided with inhibition of serum angiotensin-converting enzyme activity (p < 0.001), an increase in plasma renin activity (p = 0.022), and decreases in plasma endothelin (p = 0.035), atrial natriuretic peptide (p = 0.005), and serum aldosterone (p = 0.001) concentrations. Cardiac output, venous admixture, and oxygen delivery and consumption remained unchanged.


CONCLUSIONS
Adding enalaprilat to conventional therapy makes it possible to unload the left ventricle and to relieve overt neurohormonal activation temporarily while maintaining cardiac function and systemic oxygenation.
Tohmo
H
H
Department of Anesthesiology, Turku University Central Hospital, University of Turku, Finland.
Karanko
M
M
Klossner
J
J
Scheinin
M
M
Viinamäki
O
O
Neuvonen
P
P
Ruskoaho
H
H
D000328:Adult; D000368:Aged; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology*; D009320:Atrial Natriuretic Factor / Q000097:blood*; D006348:Cardiac Surgical Procedures / Q000009:adverse effects*; D015773:Enalaprilat / Q000494:pharmacology* / Q000627:therapeutic use; D016232:Endothelins / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D018487:Ventricular Dysfunction, Left / Q000097:blood / Q000188:drug therapy*
D000806:Angiotensin-Converting Enzyme Inhibitors; D016232:Endothelins; D009320:Atrial Natriuretic Factor; D015773:Enalaprilat