Comparison of Cystatin C and NGAL in Early Diagnosis of Acute Kidney Injury After Heart Transplantation
Abstract
Background: Acute kidney injury (AKI) is a risk factor for adverse hospital outcomes in recipients of a heart transplantation (HTx). Timely recognition of AKI is crucial for the initiation of proper treatment.
We hypothesized that serum or urine biomarkers can predict AKI. Material/Methods: In this prospective study we evaluated 117 consecutive patients after HTx.
AKI was defined as an increase of the serum creatinine level by >= 50% or a worsening of the renal function requiring renal replacement therapy during the first post-HTx week. We serially sampled serum cystatin C (S-cystatin C) as a marker of glomerular filtration and urinary neutrophil gelatinase-associated lipocalin (U-NGAL) as a marker of tubular damage.
Results: A cohort of 30 patients (25.6%) fulfilled the criteria of AKI. S-cystatin C allowed the earliest separation between the AKI and non-AKI groups, with a significant difference present as soon as 3 h after surgery and it persisted on days 7, 10, and 30.
The increase in S-cystatin C preceded the serum creatinine elevation by 4 days. In a multivariate analysis, S-cystatin C > 1.6 mg/L at 3 h after HTx predicted AKI with OR 4.3 (95% CI: 1.6-11.5).
U-NGAL was significantly higher at day 3 in the AKI group (p=0.003) and elevated S-cystatin C (>= 2.54 mg/L on day 7) could predict 1-year mortality in these HTx recipients. Conclusions: Our study showed that the measurement of S-cystatin C at 3 h after surgery may help to identify patients with high risk for renal complications.
A persistent elevation of S-cystatin C also predicts 1-year mortality.