Abstract
The utility of heart-type fatty acid binding protein (H-FABP) as a prognostic biomarker in light chain cardiac amyloidosis (AL-CA) patients remains unestablished. Consecutive patients diagnosed with AL-CA in the Heart Failure Center; Fuwai Hospital were enrolled. Baseline H-FABP levels categorized patients as low (≤ 9.5 ng/mL) or high (> 9.5 ng/mL) group. Kaplan-Meier analysis and Cox proportional hazards models were performed. Model performance was assessed using Harrell's C concordance index (C-index), integrated discrimination improvement (IDI) index, and net reclassification improvement (NRI) index. Eighty-four patients were included (mean age 60.12 ± 11.25 years; 32.1% female), with 30 (35.7%) in the high H-FABP group. Overall survival was significantly lower in the high H-FABP group. In multivariable Cox models adjusted for age, eGFR and chemotherapy, H-FABP > 9.5 ng/mL remained independently associated with an increased risk of all-cause mortality when incorporating either the European modified Mayo 2004 stages [adjusted hazard ratio (HR): 2.79, 95% confidence interval (CI): 1.49-5.22; p = 0.001] or the revised Mayo 2012 stages (HR: 2.67, 95% CI: 1.48-4.83; p = 0.001). Adding H-FABP levels significantly improved predictive performance across both baseline staging systems. For the European modified Mayo 2004 stage, the C-index increased from 0.622 to 0.663, accompanied by positive IDI (0.053) and NRI (0.294). Similarly, for the revised Mayo 2012 stage, the C-index increased from 0.611 to 0.660, with positive IDI (0.074) and NRI (0.308). Elevation of H-FABP is associated with an increased risk of all-cause mortality in patients with AL-CA. It provides significant additive prognostic value to the established staging system for prognosis in AL-CA.