title: Amrinone and dobutamine as primary treatment of low cardiac output syndrome following coronary artery surgery: a comparison of their effects on hemodynamics and outcome.
abstract: This study was undertaken in order to compare the effectiveness of amrinone and dobutamine as primary treatment of a low cardiac output (CO) after coronary artery bypass graft (CABG) surgery. Thirty patients with preoperative left ventricular dysfunction participated in this open-label randomized study. Patients were included if they failed to separate from cardiopulmonary bypass (CPB) without inotropic support or if they had a cardiac index (CI) less than 2.4 L/min/m2 after CPB regardless of the blood pressure, in the presence of adequate filling pressures. The treatment objectives were to separate from CPB and achieve a CI > or = 2.4 L/min/m2 and a mean arterial pressure > or = 70 mmHg. Patients treated with amrinone received 0.75 mg/kg followed by 10 micrograms/kg/min; when the objectives were not achieved within five minutes, another 0.75 mg/kg was given. Patients treated with dobutamine received an initial infusion of 5 micrograms/kg/min increased stepwise to 15 micrograms/kg/min if necessary. Eleven of 15 amrinone versus 6 of 15 dobutamine patients achieved the predefined treatment objectives with the test drug alone (P = NS). Comparisons of hemodynamics in patients treated solely with amrinone (n = 7) or dobutamine (n = 6) after CPB showed no significant differences between the treatment groups. The incidence of myocardial ischemia as detected by Holter monitor was 36% with amrinone and 33% with dobutamine. Two patients suffered ventricular fibrillation and two had significant supraventricular tachyarrhythmias (heart rate > 130/min) during treatment with dobutamine alone, whereas no significant arrhythmias occurred in the amrinone group (P = NS). Six dobutamine patients (40%) had postoperative myocardial infarction (MI) as opposed to none among the amrinone patients (P = 0.017). These results indicate that amrinone compares favorably with dobutamine as a primary treatment of low CO after CABG. Further study in a larger number of patients will be required in order to determine if the lower incidence of MI in the amrinone group was due to the treatment drug.
authors.affiliation: Department of Anaesthesia, University of Ottawa, Heart Institute, Ontario, Canada.
authors.forename: J Y
authors.initials: JY
authors.lastname: Dupuis
authors.forename: R
authors.initials: R
authors.lastname: Bondy
authors.forename: C
authors.initials: C
authors.lastname: Cattran
authors.forename: H J
authors.initials: HJ
authors.lastname: Nathan
authors.forename: J E
authors.initials: JE
authors.lastname: Wynands
mesh_terms: D000676:Amrinone / Q000627:therapeutic use*; D001794:Blood Pressure / Q000187:drug effects; D002302:Cardiac Output / Q000187:drug effects; D002303:Cardiac Output, Low / Q000188:drug therapy*; D002315:Cardiopulmonary Bypass; D001026:Coronary Artery Bypass; D004280:Dobutamine / Q000627:therapeutic use*; D015716:Electrocardiography, Ambulatory / Q000187:drug effects; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000187:drug effects; D009203:Myocardial Infarction / Q000503:physiopathology; D010101:Oxygen Consumption / Q000187:drug effects; D013318:Stroke Volume / Q000187:drug effects; D013577:Syndrome; D016896:Treatment Outcome; D014655:Vascular Resistance / Q000187:drug effects
chemical_list: D004280:Dobutamine; D000676:Amrinone