The S-100B substudy of the GLUTAMICS trial: glutamate infusion not associated with sustained elevation of plasma S-100B after coronary surgery.
OBJECTIVE
Concerns have been raised about potential neurological injury related to exogenous glutamate. In cardiac surgery glutamate has been administered as a putative cardioprotective agent by cardioplegia or intravenous infusion. In the GLUTAMICS trial, in addition to surveillance of clinical neurological injuries, a prespecified subgroup was analyzed with regard to postoperative S-100B levels to detect potential subclinical neurological injury related to glutamate infusion.


METHODS
Sixty-nine patients operated on for unstable coronary syndrome were randomized to intravenous infusion of glutamate (n=35) or saline (n=34) perioperatively. Plasma levels of S-100B were obtained on the third postoperative day.


RESULTS
S-100B in the glutamate group and the control group were 0.079+/-0.034microg/L and 0.090+/-0.042microg/L respectively (p=0.245). There were no patients with stroke or mortality. Three patients in the control group and two in the glutamate group had postoperative confusion. These patients had significantly elevated S-100B compared with those without confusion (0.132+/-0.047vs 0.081+/-0.036microg/L; p=0.003). Overall, 21 patients had S-100B above reference level (> or =0.10microg/L) and these patients had significantly more calcifications in the ascending aorta on epiaortic scanning.


CONCLUSIONS
Intravenous glutamate infusion during surgery for unstable coronary artery disease did not initiate a sustained elevation of plasma S-100B. Thus, no evidence for subclinical neurological injury related to glutamate infusion was found. In contrast, postoperative elevation of plasma S-100B was linked to calcification of the ascending aorta and postoperative confusion.
Department of Cardiothoracic Surgery and Anesthesia, University Hospital Orebro, Sweden.
Mårten
M
Vidlund
Jonas
J
Holm
Erik
E
Håkanson
Orjan
O
Friberg
Lena
L
Sunnermalm
Farkas
F
Vanky
Rolf
R
Svedjeholm
D000368:Aged; D001011:Aorta / Q000000981:diagnostic imaging; D001018:Aortic Diseases / Q000000981:diagnostic imaging; D015415:Biomarkers / Q000097:blood; D002114:Calcinosis / Q000097:blood / Q000150:complications / Q000000981:diagnostic imaging; D002316:Cardiotonic Agents / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use; D003221:Confusion / Q000097:blood / Q000209:etiology; D001026:Coronary Artery Bypass / Q000009:adverse effects / Q000401:mortality; D003324:Coronary Artery Disease / Q000097:blood / Q000150:complications / Q000601:surgery; D005260:Female; D018698:Glutamic Acid / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D008875:Middle Aged; D009414:Nerve Growth Factors / Q000097:blood*; D020258:Neurotoxicity Syndromes / Q000097:blood* / Q000175:diagnosis / Q000209:etiology; D011183:Postoperative Complications / Q000097:blood / Q000139:chemically induced; D011184:Postoperative Period; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins / Q000097:blood*; D014463:Ultrasonography
D015415:Biomarkers; D002316:Cardiotonic Agents; D009414:Nerve Growth Factors; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins; D018698:Glutamic Acid