Glucose-insulin-potassium and tri-iodothyronine individually improve hemodynamic performance and are associated with reduced troponin I release after on-pump coronary artery bypass grafting.
BACKGROUND
Both glucose-insulin-potassium (GIK) and tri-iodothyronine (T3) may improve cardiovascular performance after coronary artery surgery (CABG) but their effects have not been directly compared and the effects of combined treatment are unknown.


RESULTS
In 2 consecutive randomized double-blind placebo-controlled trials, in patients undergoing first time isolated on-pump CABG between January 2000 and September 2004, 440 patients were recruited and randomized to either placebo (5% dextrose) (n=160), GIK (40% dextrose, K+ 100 mmol.L(-1), insulin 70 u.L(-1)) (0.75 mL.kg(-1) h(-1)) (n=157), T3 (0.8 microg.kg(-1) followed by 0.113 microg.kg(-1) h(-1)) (n=63) or GIK+T3 (n=60). GIK/placebo therapy was administered from start of operation until 6 hours after removal of aortic cross-clamp (AXC) and T3/placebo was administered for a 6-hour period from removal of AXC. Serial hemodynamic measurements were taken up to 12 hours after removal of AXC and troponin I (cTnI) levels were assayed to 72 hours. Cardiac index (CI) was significantly increased in both the GIK and GIK/T3 group in the first 6 hours compared with placebo (P<0.001 for both) and T3 therapy (P=0.009 and 0.029, respectively). T3 therapy increased CI versus placebo between 6 and 12 hours after AXC removal (P=0.01) but combination therapy did not. Release of cTnI was lower in all treatment groups at 6 and 12 hours after removal of AXC.


CONCLUSIONS
Treatment with GIK, T3, and GIK/T3 improves hemodynamic performance and results in reduced cTnI release in patients undergoing on-pump CABG surgery. Combination therapy does not provide added hemodynamic effect.
Ranasinghe
Aaron M
AM
Department of Cardiothoracic Surgery, University Hospital Birmingham, Edgbaston, Birmingham, B15 2TH, UK.
Quinn
David W
DW
Pagano
Domenico
D
Edwards
Nicola
N
Faroqui
Muzzafar
M
Graham
Timothy R
TR
Keogh
Bruce E
BE
Mascaro
Jorge
J
Riddington
David W
DW
Rooney
Stephen J
SJ
Townend
John N
JN
Wilson
Ian C
IC
Bonser
Robert S
RS
D000368:Aged; D015415:Biomarkers; D002314:Cardioplegic Solutions / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D002315:Cardiopulmonary Bypass / Q000009:adverse effects; D002316:Cardiotonic Agents / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D001026:Coronary Artery Bypass / Q000706:statistics & numerical data*; D004298:Dopamine / Q000008:administration & dosage / Q000627:therapeutic use; D004311:Double-Blind Method; D004359:Drug Therapy, Combination; D005260:Female; D005947:Glucose / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D007328:Insulin / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D015428:Myocardial Reperfusion Injury / Q000503:physiopathology / Q000517:prevention & control*; D009638:Norepinephrine / Q000008:administration & dosage / Q000627:therapeutic use; D011188:Potassium / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D011446:Prospective Studies; D014284:Triiodothyronine / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D019210:Troponin I / Q000097:blood*; D014662:Vasoconstrictor Agents / Q000008:administration & dosage / Q000627:therapeutic use
D015415:Biomarkers; D002314:Cardioplegic Solutions; D002316:Cardiotonic Agents; D007328:Insulin; D019210:Troponin I; D014662:Vasoconstrictor Agents; C030396:glucose-insulin-potassium cardioplegic solution; D014284:Triiodothyronine; D005947:Glucose; D011188:Potassium; D004298:Dopamine; D009638:Norepinephrine