Predicting acute kidney injury after cardiac surgery: much work still to be done

Accurate preoperative risk prediction for perioperative complications such as acute kidney injury (AKI) may serve to better inform patients and families of risk before surgery, assist with resource requirement planning, and aid with cohort enrichment for enrolment into clinical trials. Where a specific risk factor is modifiable, it may offer a potential therapeutic target for risk reduction. The report by Wang and colleagues describes the modest incremental benefit of N-terminal pro brain natriuretic peptide levels when added to almost 20 other variables for the preoperative prediction of AKI after cardiac surgery. This is consistent with previous smaller studies, but there are important additional questions still to be answered before this biomarker might be used for this purpose in clinical practice.