Cystatin-C as an Early Marker of Cardiac Surgery Associated-Acute Kidney Injury (CSA-AKI) in Children with Congenital Heart Diseases in Southwest Nigeria

The Editor, We are writing in response to the letter sent to the editor concerning our published manuscript “Cardiac Surgery-Associated Acute Kidney Injury (CSA-AKI) in Children with Congenital Heart Diseases in Southwest Nigeria” with the following point by point clarifications. In response to the first point, the unit of the cystatin-C of ng/dl was deliberately chosen and validated and this was reflected in almost all our reporting in the manuscript, the only ng/ml was in Table 5, and we are very sorry but it was a typographical error. On the second point raised, Table 3 and the results are consistent, the participants with CSA-AKI are the ones with present, while the absent are those without CSA-AKI with values corresponding accordingly, the higher values are for those with CSA-AKI designated as present which is the opposite of what the responders have written, they should kindly look through the table again. Also, the mean value at 8 hours was for all participants, with and without CSA-AKI. Concerning the third point, the creatinine was assayed using automated Cobas c311 chemistry analyzer machine that uses the Jaffe kinetic method. As discussed in our introduction, creatinine has a lot of the drawbacks especially in children with congenital heart diseases undergoing open heart surgery that includes the younger age, dilutional effect of the cardiopulmonary bypass (CPB) pump prime, prolonged CPB time, interruptions, and alterations in the renal blood flow during CPB. We are very grateful for the interest shown in our work and the opportunity given to us in the publication of our manuscript. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.