Effectiveness of Serum Cystatin C Level for Predicting Acute Kidney Injury Following Adult On-pump Cardiac Surgery

Acute kidney injury (AKI) following adult cardiac surgery procedures under Cardio-pulmonary bypass (CPB) is linked to a higher risk of morbidity and death. As a novel biomarker for renal failure, serum Cystatin C (CysC) is of prognostic value; however, a wide range of its predictive accuracy has been reported. The study aimed to evaluate whether early postoperative serum CysC measurement improves the prediction of AKI following adult cardiac surgery and determine the relationship between the measurement of early postoperative serum CysC level and post-operative early outcomes. In a single-center, prospective study of 70 patients was conducted at the National Institute of Cardiovascular Diseases (NICVD), Dhaka, Bangladesh from July 2018 to December 2019 who underwent on-pump cardiac surgery. The study participants were chosen specifically because they had normal renal function and had had elective scheduled heart surgery under CPB. The blood samples were tested at six measurements time points (T1 preoperative, T2 at 6 hours after commencement of CPB, T3 at 12 hours after commencement of CPB, T4 at 24 hours after commencement of CPB, T5 at 36 hours after commencement of CPB and T6 at 48 hours after commencement of CPB). Serum cystatin C was significantly higher 12 hours after the commencement of CPB during operation (T3) and onwards when the earliest significant predictive AUCs were found (T3: AUC 0.983; p<0.0001; 95% CI, 0.960 to 1.000; T4-6: AUC 1.000; p<0.0001; 95% CI, 1.000). In summary, this study found that serum CysC is a useful early biomarker of AKI in adults following cardiac surgery, and the extent of this marker correlates with the severity of AKI.