Alpha glutathione S-transferase: a potential marker of ischemia-reperfusion injury of the intestine after cardiac surgery?

Background: The aim of the study was to assess the utility of alpha glutathione S-transferase (alphaGST) as a potential marker of intestinal ischemia-reperfusion injury in children after cardiac surgery.

Methods: Twenty-six patients undergoing cardiac surgery were enrolled in this longitudinal experimental study. Blood samples were drawn for analysis at specified time points during surgery and analyzed for alphaGST levels. Clinical indices of splanchnic morbidity were assessed up to discharge from hospital. Results were analyzed using Mann-Whitney tests and linear mixed effects models.

Results: Two groups were identified. Group 1 (n = 16) showed no intestinal morbidity and group 2 (n = 10) had signs of intestinal morbidity. Statistical differences were shown between the 2 groups with respect to time with aortic cross-clamp (ACC) in situ, time on cardiac bypass, duration of operation, time to enteral feeding and full feeding, time on mechanical ventilation, and time in the intensive care unit postoperatively. The serum concentration of alphaGST was significantly higher for group 2 and this rise was greatest after removal of the ACC.

Conclusions: AlphaGST showed significant elevation in patients with prolonged bypass times and ACC times. These patients also displayed signs of intestinal morbidity, suggesting that this marker may be useful in screening patients at risk for intestinal pathology. This rise in alphaGST was associated with a prolonged ischemia time, and was greatest after the cross-clamp was released, suggesting that it is a postischemic reperfusion phenomenon leading to its elevation. A low alphaGST level appears to exclude significant intestinal ischemia.