title: Enalaprilat in acute intractable heart failure after myocardial infarction: a prospective, consecutive sample, before-after trial.
abstract: OBJECTIVE
  To evaluate the acute effects of intravenous enalaprilat infusion in critically ill patients with intractable heart failure after acute myocardial infarction.
  
  
  METHODS
  Prospective, consecutive sample, before-after trial.
  
  
  METHODS
  Medical intensive care unit in a university hospital.
  
  
  METHODS
  Eight consecutive patients with intractable acute heart failure after acute myocardial infarction. All study patients continued receiving inotropic, vasodilating, and diuretic medication at a constant rate. Six patients received steady intermittent mandatory ventilation and two patients were on a continuous positive airway pressure mask during the investigation, all with constant positive end-expiratory pressure. Heart failure was defined as intractable if the pulmonary artery occlusion pressure remained > 20 mm Hg despite this conventional therapy.
  
  
  METHODS
  Enalaprilat was infused at a rate of 1 mg/hr until the pulmonary artery occlusion pressure decreased by > or = 20%.
  
  
  RESULTS
  Central hemodynamics, oxygenation, and hormonal regulation (plasma renin activity, plasma norepinephrine, epinephrine, endothelin, atrial natriuretic peptide, and vasopressin concentrations, serum angiotensin-converting enzyme activity, and serum concentrations of aldosterone) were assessed at baseline before enalaprilat infusion, and repeatedly during 2 hrs after the infusion. The statistical analysis was performed with analysis of variance for repeated measurements. Enalaprilat infusion (median dose 0.3 mg and infusion time 21 mins) caused significant but short-lasting decreases in pulmonary artery occlusion pressure (p = .007), mean arterial pressure (p = .003), mean pulmonary arterial pressure, and rate pressure product. These findings coincided with inhibition of serum angiotensin-converting enzyme activity, an increase in plasma renin activity, and a decrease in plasma endothelin concentrations (p = .041). Enalaprilat had no significant effects on the other hormones studied. Cardiac output and stroke volume index, venous admixture, oxygen extraction ratio, and mixed venous and arterial oxygen saturations remained unchanged.
  
  
  CONCLUSIONS
  Adding enalaprilat to conventional therapy makes it possible to transiently relieve pulmonary congestion while maintaining cardiac function and systemic oxygenation. The decrease in plasma endothelin concentrations may have further clinical implications, because endothelin is known to have potent vasoconstricting effects on the coronary circulation and it may also contribute to the extension of myocardial infarction. Whether these observed benefits can be maintained with repeated bolus injections or with continuous infusion of enalaprilat, remains to be settled.
authors.affiliation: Department of Anesthesiology, Turku University Central Hospital, Finland.
authors.forename: H
authors.initials: H
authors.lastname: Tohmo
authors.forename: M
authors.initials: M
authors.lastname: Karanko
authors.forename: K
authors.initials: K
authors.lastname: Korpilahti
authors.forename: M
authors.initials: M
authors.lastname: Scheinin
authors.forename: O
authors.initials: O
authors.lastname: Viinamäki
authors.forename: P
authors.initials: P
authors.lastname: Neuvonen
mesh_terms: D000208:Acute Disease; D000368:Aged; D003131:Combined Modality Therapy; D015773:Enalaprilat / Q000627:therapeutic use*; D005260:Female; D005387:Finland / Q000453:epidemiology; D006333:Heart Failure / Q000188:drug therapy* / Q000453:epidemiology / Q000209:etiology / Q000503:physiopathology; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications / Q000188:drug therapy* / Q000453:epidemiology / Q000503:physiopathology; D011446:Prospective Studies; D013223:Statistics as Topic / Q000379:methods; D013997:Time Factors
chemical_list: D015773:Enalaprilat