The Efficacy of Amrinone or Adrenaline on Low Cardiac Output Following Cardiopulmonary Bypass in Patients with Coronary Artery Disease Undergoing Preoperative ß-Blockade

Abstract

We examined 20 patients undergoing coronary bypass grafting for coronary artery disease with NYHA classifications of II and III who had been treated with beta-blocking agents. Patients were randomised for administration of either adrenaline (0.1 microgram/kg/min) or amrinone (bolus 1 mg/kg, continuous infusion of 5-10 micrograms/kg/min), if following cardiopulmonary bypass their cardiac index was < 2.4 L/min/m2 with normal peripheral resistance and normal or increased right- or left-ventricular filling pressures. Over a period of 1 hour, the hemodynamic parameters mean arterial pressure (MAP), cardiac index (CI), heart rate (HR), coronary perfusion pressure (CPP), total peripheral resistance (TPR), as well as the pressure-work index (PWI) were registered or calculated. By means of a coronary sinus catheter myocardial arterio-venous oxygen content difference (AVDO2cor), myocardial blood flow (MBF), using the thermodilution method, and myocardial oxygen consumption (MVO2) could be measured or calculated. Simultaneously, arterial and myocardial lactate concentrations and, using the arterio-venous lactate ratio, myocardial lactate extraction or production were quantified. Using a transseptal approach, the left-ventricular pressure curve was measured and used to differentiate for myocardial contractility (dp/dtmax). Following induction of anesthesia and after cardiopulmonary bypass, plasma levels of the used beta-blocking agent were determined. Both substances caused a significant increase in myocardial contractility, with adrenaline showing a more potent effect than amrinone. Both substances caused a significant increase in CI with a mild increase in HR. Amrinone caused a significant drop in TPR, while MAP remained practically constant.(ABSTRACT TRUNCATED AT 250 WORDS)

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“…No study yielding 'level I' evidence (Table 1) was identified. Only one uncontrolled study, that by Gunnicker and coworkers [5], specifically investigated its effectiveness in LCOS.…”

“…In that report [5], epinephrine at a dose of 0.03 μg/kg per min produced significant increases in CI and heart rate (HR) of 24.1% and 14.1%, respectively, compared with placebo. HR was minimally affected in all studies except that of Gunnicker and coworkers, in which it increased by 14%.…”

“…Two small, randomized controlled trials [5,8] compared epinephrine with the PDI amrinone. In both studies, both drugs significantly increased CI from baseline.…”

Perioperative Anesthesia Management in Secondary Mitral Regurgitation and Heart Failure

“…PDI, such as amrinone, milrinone or enoximone, are all potent vasodilators that cause reductions in cardiac fi lling pressures, PVR and SVR [ 152 , 153 ], and, compared to dobutamine, decrease the likelihood of arrhythmias and cause less tachycardia [ 154 -156 ]. PDI, despite increasing HR and contractility, being powerful vasodilators are able to decrease LV wall tension and therefore might increase MVO 2 less, compared to catecholamines [ 157 ]. PDI are independent of beta-receptor signaling because indirectly promote myocardial contractility by raising intracellular cyclic adenosine monophosphate and thereby cytosolic calcium concentrations [ 81 ].…”

Intérêt des bêta-bloquants en médecine périopératoire. Deuxième partie: indications thérapeutiques

“…Après administration chronique de BB cardiosélectifs (méto-prolol, bisoprolol, aténolol), leurs taux sériques baissent de 45-50% après la circulation extracorporelle et, en cas de bas débit cardiaque, l'adrénaline s'avère aussi efficace que l'amrinone. 43 La labétalol utilisé après revascularisation coronarienne diminue, selon les patients, soit le débit cardiaque, soit les résistances vasculaires périphériques. Une baisse significative de la fréquence et du débit cardiaques, sans réduction des résistances systémiques, a été rapportée, suggérant que le bêta-blocage l'emporte sur l'alpha-blocage, surtout lorsque le labétalol est utilisé par voie veineuse.…”