Efflux of adenosine and its catabolites during cold blood cardioplegia.
Levels of myocardial high-energy phosphates decrease during cardioplegia for open heart operations, with a subsequent increase in the level of adenosine and its metabolites. It has been demonstrated in experimental models that the effluent concentrations of purines can be used as a measure of the average myocardial energy state. Net adenylate loss and myocardial energy state were evaluated here by determining aorta-coronary sinus differences in levels of adenosine catabolites in 17 patients during cold blood cardioplegia for elective coronary artery bypass grafting. Repeated blood samples were taken before cross-clamping of the aorta, when cardioplegic solute was infused into the aortic root and grafts after five distal anastomoses, and after declamping of the aorta. The aorta-coronary sinus differences in levels of total purines increased 4.7-, 7.5-, 7.1-, 7.8-, and 10.2-fold (from the preclamp level of 1.7 +/- 0.7 mumol/L; p < 0.001) for grafts one through five anastomosed at an average of 19, 34, 50, 63, and 76 minutes after the aortic cross-clamp, respectively. Hypoxanthine and xanthine were present in the highest concentrations. Vasodilatory adenosine concentrations of 1 to 2 mumol/L were observed in the coronary sinus while the aorta was cross-clamped. There was a linear positive correlation between the aorta-coronary sinus purine differences and corresponding cross-clamp time (r = 0.62; p < 0.001). The metabolite differences settled at a more negative level after declamping of the aorta than that prevailing before placement of the cross-clamp, suggesting continuous washout of adenosine and its catabolites during the 30-minute postclamp observation period.(ABSTRACT TRUNCATED AT 250 WORDS)
Department of Cardiothoracic Surgery, Oulu University Central Hospital, Finland.
J
J
Nissinen
M J
MJ
Raatikainen
K
K
Karlqvist
K J
KJ
Peuhkurinen
D000241:Adenosine / Q000097:blood / Q000378:metabolism*; D001769:Blood; D001800:Blood Specimen Collection / Q000379:methods; D002851:Chromatography, High Pressure Liquid; D003080:Cold Temperature; D001026:Coronary Artery Bypass; D004734:Energy Metabolism / Q000502:physiology; D005260:Female; D006324:Heart Arrest, Induced / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods; D009206:Myocardium / Q000378:metabolism*; D013997:Time Factors
D000241:Adenosine