Elevation of urinary liver-type fatty acid binding protein after cardiac catheterization related to cardiovascular events

Abstract

Purpose: Contrast medium (CM) induces tubular hypoxia via endothelial damage due to direct cytotoxicity or viscosity. Urinary liver-type fatty acid binding protein (L-FABP) increases along with tubular hypoxia and may be a detector of systemic circulation injury. The aim of this study was to evaluate the clinical usefulness of detecting increases in urinary L-FABP levels due to administration of CM, as a prognostic biomarker for cardiovascular disease in patients without occurrence of CM-induced nephropathy undergoing cardiac catheterization procedure (CCP).

Methods: Retrospective longitudinal analyses of the relationship between urinary L-FABP levels and occurrence of cardiovascular events were performed (n=29). Urinary L-FABP was measured by ELISA before CCP, and at 6, 12, 24, and 48 hours after CCP.

Results: Urinary L-FABP levels were significantly higher at 12 hours (P<0.05) and 24 hours (P<0.005) after CCP compared with before CCP, only in the patients with occurrence of cardiovascular events (n=17), but not in those without cardiovascular events (n=12). The parameter with the largest area under the curve (0.816) for predicting the occurrence of cardiovascular events was the change in urinary L-FABP at 24 hours after CCP. The difference in urinary L-FABP levels (ΔL-FABP ≥11.0 μg/g creatinine) between before CCP and at 24 hours after CCP was a risk factor for the occurrence of cardiovascular events (hazard ratio, 4.93; 95% confidence interval, 1.27-19.13; P=0.021).

Conclusion: Measurement of urinary L-FABP before CCP and at 24 hours after CCP in patients with mild to moderate renal dysfunction may be an important indicator for risk stratification of onset of cardiovascular events.

Keywords: L-FABP; cardiovascular event; chronic kidney disease; contrast medium; renal dysfunction; urinary biomarker; urinary liver-type fatty acid binding protein.

Figure 1

Changes in urinary albumin, NAG, and urinary L-FABP levels before and after CCP. Notes: (A) Changes in urinary albumin levels in all patients (n=38). (B) Changes in urinary NAG levels in all patients (n=38). (C) Changes in urinary L-FABP levels in all the patients (n=38). *P<0.005 compared with the value before CCP; ^§P<0.0001 compared with the value before CCP. Abbreviations: NAG, N-acetyl-β-d-glucosaminidase; L-FABP, liver-type fatty acid binding protein; CCP, cardiac catheterization procedure.

Figure 2

Changes in urinary albumin, NAG, and urinary L-FABP levels before and after CCP divided into two groups according to the occurrence of cardiovascular events. Notes: Group without occurrence of cardiovascular events (dotted line) (n=12); group with occurrence of cardiovascular events (straight line) (n=17). (A) Changes in urinary albumin levels in the patients enrolled to the longitudinal study. (B) Changes in urinary NAG levels in the patients enrolled to the longitudinal study. (C) Changes in urinary L-FABP levels in the patients enrolled to the longitudinal study. *P<0.005 compared with the respective value before CCP; **P<0.05 compared with the respective value before CCP; ^#P<0.05 compared with the group without occurrence of cardiovascular events at the same time point. Abbreviations: NAG, N-acetyl-β-d-glucosaminidase; L-FABP, liver-type fatty acid binding protein; CCP, cardiac catheterization procedure.

Figure 3

Event-free rate of cardiovascular events according to the Kaplan–Meier method. Notes: Non-increase group with ΔL-FABP from before CCP to 24 hours after CCP <11.0 μg/g creatinine (dotted line) (n=13); increase group with ΔL-FABP before-at 24 hours ≥11.0 μg/g creatinine (straight line) (n=16). Differences between groups were compared by a log-rank test. Abbreviation: ΔL-FABP, difference in urinary liver-type fatty acid binding protein.