Myocardial injury occurs inpatients undergoing coronary artery bypass grafting
(CABG) with and without cardiopulmonarybypass (CPB) (on-pump CABG) and (off-pump CABG) respectively. The extent of damage in both groups can be evaluated by
the use of heart-type fatty-acid–binding protein (hFABP) and creatine kinase-MB
(CK-MB) release. Also, cardiac surgery with the use of extra corporealcirculation
(ECC) is associated with oxidative stress. The present study aims to evaluate
myocardial injury and oxidative stress in these two groups, comparing between the
two parameters indicating cardiac damage, also oxidative stress status was assessed
by estimating serum levels of isoprostane during these major operations. Fifty adult
patients of either sex were distributed to 1 of 2 groups: on-pump (n= 25), in which
coronary revascularization was done with the use of CPB and moderate hypothermia;
and off-pump (n=25), in which surgery was performed without the use of CPB.
Twenty five healthy control subjects were also enrolled in the study. The current study
showed a significant increase in the mean serum levels of h-FABP in on- pump and
off pump groups compared to the control group. (133.60±49.41,58.29±16.67 and
4.33±2.97ng/ml respectively, p<0.001), and in the on-pump CABG group compared
to off-pump CABG group (133.60±49.41vs 58.29±16.670ng/ml, P<0.001). The total
amount of CK-MB released was significantly higher in the on-pump group compared
to the off-pump and control groups (210.80 ± 32 .47 , 20.19 ± 4.22 and 13.70± 1.64
U/ml respectively, P<0.001). While there was no significant difference in the serum
levels of CK-MB between both off pump and control groups (20.19 ± 4.222 and
13.70± 1.64 U/ml. There was a significant increase in the mean levels of serum
isoprostane in on- pump and off pump groups compared to the control group
(431.14±51.525, 329.83±24.620 and 132.34±15.57ng/ml respectively, p<0.001), and
in the on-pump group compared to the off pump group (431.14±51.52 vs
329.83±24.62 ng/ml P<0.001). The lower levels of hFABP in the off-pump CABG
group indicate that on-pump CABG with cardioplegic arrest causes more myocardial
damage than does off-pump CABG. While normal CK- MB levels in the off –pump
group indicate that this marker cannot detect the minor damage in that group, a
finding which was detected by hFABP which increased significantlyin the off-pump
CABG group compared to the controls. So, hFABP could be considered a better
marker for early intraoperative detection of minimal cardiac damage.