Correlation Between Cardiac Index, Plasma Troponin I, Myocardial Histopathology, CPB and AoX Duration in Glutamine versus No Glutamine Administered Patients with Low Ejection Fraction Undergoing Elective On-Pump CABG Surgery: Secondary Analysis of an RCT.

Purpose: On-pump coronary artery bypass graft (CABG) causes myocardial ischemia, through the cardiopulmonary bypass (CPB) and aortic cross-clamping (AoX). Glutamine supplementation protects cardiac cells during cardiac ischemia. This study analysed the correlation between cardiac index (CI), plasma troponin I, myocardial histopathology, CPB and AoX duration in low ejection fraction patients receiving glutamine and no glutamine undergoing elective on-pump CABG.

Material and methods: This was a secondary analysis of a double-blind, randomised controlled trial of 60 patients, split into control and intervention (glutamine) groups. Glutamine was administered at a dose of 0.5 g/kg/24 hours. There were 29 patients in each respective groups after a total of two patients dropped out.

Results: A negative correlation (p = 0.037) was observed between CPB duration and CI at 6 hours after CPB in the glutamine group. A positive correlation (p = 0.002) was also observed between AoX duration and plasma troponin I at 6 hours after CPB in the control group. However, no correlation was observed between myocardial histopathology and plasma troponin I level at 5 minutes after CPB.

Conclusion: Significant negative correlation between CPB duration and CI at 6 hours after CPB in the glutamine group, along with significant positive correlation between AoX duration and plasma troponin I level at 6 hours after CPB in the control group demonstrated the myocardial protection qualities of intravenous glutamine administration in patients with low ejection fraction undergoing elective on-pump CABG surgeries.