Does glutamate influence myocardial and peripheral tissue metabolism after aortic valve replacement for aortic stenosis?
OBJECTIVE
Glutamate plays an important role for myocardial metabolism in association with ischaemia. Patients with coronary artery disease characteristically demonstrate increased uptake of glutamate. Improved recovery of myocardial metabolism and haemodynamic state after coronary surgery has been reported in patients treated with glutamate infusion. However, the effect of glutamate has not been studied after other cardiac surgical procedures. In addition, the effects of glutamate on peripheral tissue metabolism remain to be described.


METHODS
Twenty patients undergoing surgery for aortic stenosis were studied after randomisation to blinded infusion of glutamate or saline during 1h immediately after skin closure. Myocardial and leg tissue metabolism were assessed with organ balance techniques.


RESULTS
Postoperative glutamate infusion induced a marked increase in myocardial and leg tissue uptake of glutamate. This was associated with a significant uptake of lactate in the heart. The negative arterial-venous differences of amino acids and free fatty acids across the leg were significantly smaller in the glutamate group. Haemodynamic state remained stable and did not differ between groups.


CONCLUSIONS
The heart and peripheral tissues consumed the exogenously administered glutamate after surgery for aortic stenosis. Potentially favourable effects of glutamate on myocardial and peripheral tissue metabolism are suggested.
Vánky
Farkas B
FB
Department of Cardiothoracic Surgery, Linköping Heart Centre, University Hospital, SE-581 85 Linköping, Sweden.
Håkanson
Erik
E
Jorfeldt
Lennart
L
Svedjeholm
Rolf
R
D000368:Aged; D001024:Aortic Valve Stenosis / Q000601:surgery*; D001774:Blood Chemical Analysis; D001775:Blood Circulation / Q000187:drug effects; D004311:Double-Blind Method; D004734:Energy Metabolism / Q000502:physiology; D005260:Female; D018698:Glutamic Acid / Q000494:pharmacology*; D019918:Heart Valve Prosthesis Implantation; D006801:Humans; D007263:Infusions, Parenteral / Q000379:methods; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism*; D010101:Oxygen Consumption; D011182:Postoperative Care / Q000379:methods; D016896:Treatment Outcome
D018698:Glutamic Acid