Methods: A total of 40 children with congenital heart disease (17 males, 23 females; mean age: 39.6±40.0 months; range, 2 to 216 months) who underwent open-heart surgery were included. The control group consisted of 40 age- and sex-matched healthy children (18 males, 22 females; mean age: 42.8±46.6 months; range, 12 to 156 months). The patients with congenital heart disease were divided into two groups as cyanotic patients (n=18) and acyanotic patients (n=22). Thiol/disulfide parameters were compared among the cyanotic, acyanotic congenital heart disease patients, and control group preoperatively (pre-CPB). The effects of cardiopulmonary bypass on thiol/disulfide parameters, pre-CBP, immediately after cardiopulmonary bypass (post-CPB0), and 24 h after cardiopulmonary bypass (post-CPB24) were investigated.

Results: The mean native and total thiol levels in the cyanotic patients were significantly lower than those in the acyanotic patients and control group (p<0.0001). The cyanotic group exhibited higher disulfide levels than the acyanotic group (p<0.01). The mean native thiol and total thiol levels significantly decreased in the post-CPB0 (p<0.0001). The mean disulfide levels significantly increased in the post-CPB0 than the pre-CPB values (p<0.001). Post-CPB24 native and total thiol levels were elevated compared to post-CPB0 (p<0.0001). The mean disulfide levels significantly increased in the post-CPB24 period than the post-CPB0 values (p<0.001). The survivor patients responded better to oxidative stress than non-survivor patients.

Conclusion: Thiol/disulfide measurement is a promising biomarker in determining the pre- and post-cardiopulmonary bypass oxidative status of pediatric patients undergoing congenital heart surgery. The interpretation of thiol/disulfide levels, pre- and postoperatively, may be used in predicting mortality and outcomes of these patients earlier.