Pre-operative growth differentiation factor 15 as a novel biomarker of acute kidney injury after cardiac bypass surgery.

BACKGROUND

Pre-operative GDF-15 plasma levels significantly improve the prognostic value of the EuroSCORE for mortality after cardiac surgery. However, despite the strong correlation between GDF-15 and renal function, no data are available regarding the potential interest of pre-operative GDF-15 levels to improve the prediction of acute kidney injury (AKI) after cardiac artery bypass graft (CABG) surgery.

METHODS

All patients operated on by 2 surgeons for CABG surgery at our university hospital from September 2011 to March 2013 were screened for participation in this prospective, observational study.

EXCLUSION CRITERIA

age <18years or >80years, previous atrial fibrillation/flutter, previous severe renal failure, previous cardiac surgery, emergency surgery. AKI was defined according to KDIGO criteria. GDF-15 levels in plasma were measured before induction and 12h after surgery.

RESULTS

134 patients were included in this study. 42 (31%) developed post-operative AKI. AKI patients had a significantly higher pre-operative log-GDF-15 level (OR=3.64; 95% CI=1.41-9.40, p=0.008), a lower pre-operative eGFR (OR=0.98; 95% CI=0.96-0.99; p=0.026), and most often underwent on-pump surgery (OR=2.60; 95% CI=1.14-5.96, p=0.024). On ROC curves, GDF-15 before induction was found to be the best pre-operative biomarker to predict AKI (AUC=0.83; CI=0.75-0.89), compared with eGFR (AUC=0.67; 95% CI=0.59-0.75), p=0.003 and NT-proBNP (AUC=0.62; CI=0.51-0.72), p<0.001. Pre-operative GDF-15 was also significantly better than the EuroSCORE in predicting AKI (AUC 0.62, 95% CI=0.54-0.70), p<0.001.

CONCLUSIONS

Pre-operative GDF-15 plasma levels are associated with post-operative AKI in CABG patients. If confirmed in larger cohorts, pre-operative GDF-15 may be of value to improve pre-operative risk stratification among candidates for surgery.