DOES INTRAVENOUS GLUTAMATE INFUSION INFLUENCE THE USE OF INOTROPIC DRUGS IN PATIENTS OPERATED FOR ACUTE CORONARY SYNDROME?

Abstract: Introduction: In a double-blind randomized clinical trial (GLUTAMICS-ClinicalTrials.gov Identifier: NCT00489827), intravenous glutamate was associated with a risk reduction exceeding 50% for developing severe circulatory failure after isolated coronary artery bypass graft (CABG) for acute coronary syndrome (ACS). Here our aim was to investigate if glutamate also influenced the need or use of inotropes. Methods: Post hoc analysis of 824 patients in the GLUTAMICS-trial operated with isolated CABG for ACS. ICU-records were retrospectively scrutinized including hourly registration of inotropic drug infusion, dosage and total duration during the operation and postoperatively. Results: ICU-records were available for 171 out of 177 patients who received inotropes preoperatively. Only 26% of the patients treated with inotropes fulfilled study criteria for postoperative heart failure at weaning from CPB or later in the ICU. Inotropes were mainly given preemptively to facilitate weaning from CPB or to treat postoperative circulatory instability (bleeding, hypovolemia). With the exception of significantly lower need of epinephrine there were only trends towards lower need of other inotropes overall in favour of glutamate. In patients treated with inotropes (glutamate n=17; placebo n=13) who fulfilled criteria for left ventricular failure at weaning from CPB the average duration of inotropic treatment (34±20 v 80±77 hours; p= 0.014) and the number of inotropes used (1.35 ±0.6 v1.85±0.7; p=0.047) were lower in the glutamate group. Discussion: Intravenous glutamate had a limited effect on inotrope use overall in patients undergoing CABG for ACS whereas a substantial and significant effect was observed in patients with left ventricular failure at weaning from CPB. Glutamate treatment may therefore help patients predicted postoperative ventricular failure.