Serum beta-2 microglobulin levels for predicting acute kidney injury complicating aortic valve replacement

Acute kidney injury complicating both transcatheter and surgical aortic valve replacement is associated with high rates of morbidity and mortality. The aim of this study was to investigate the role of serum beta 2 (β2) microglobulin, cystatin C and neutrophil gelatinase-associated lipocalin levels in detecting periprocedural acute kidney injury.

Eighty consecutive patients who were 70 years of age or older and who were having surgical (n = 40) or transcatheter (n = 40) aortic valve replacement were recruited in a prospective study. The biomarkers were tested before the procedure, 6 times afterwards, at discharge and at a 6-month follow-up visit.

The baseline β2-microglobulin level was the strongest predictor of acute kidney injury as a complication of transcatheter aortic valve replacement [odds ratio (OR) 5.277, P = 0.009]. Its level 24 h after the procedure reached the largest area under the curve (AUC) of 0.880 (P < 0.001) for detecting acute kidney injury. In multivariate logistic regression analysis, the levels of β2-microglobulin and cystatin C 24 h after the procedure were significantly associated with acute kidney injury after transcatheter valve replacement (OR 38.15, P = 0.044; OR 1782, P = 0.019, respectively). In the surgical aortic valve replacement group, the highest AUCs belonged to β2-microglobulin and cystatin C at 24 h (AUC = 0.808, P = 0.003 and AUC = 0.854, P = 0.001, respectively). Their higher values were also associated with acute kidney injury (OR 17.2, P = 0.018; OR 965.6, P = 0.02, respectively). A persistent increase in the postoperative levels of β2-microglobulin following acute kidney injury was associated with the progression of chronic kidney disease for 6 months after both transcatheter (OR 6.56, P = 0.030) and surgical (OR 7.67, P = 0.03) aortic valve replacements.

Serum β2-microglobulin had the potential to predict acute kidney injury complicating transcatheter valve replacement and to diagnose it as early as 24 h after both the transcatheter and the surgical procedures. Furthermore, the serum level of β2-microglobulin was indicative of the progression of chronic kidney disease.