Clinical utility of fibrosis-4 index in predicting increased right atrial pressure

Abstract Introduction Fibrosis-4 (FIB-4) index, derived from serum aspartate transaminase, alanine aminotransferase, platelet count and age, is an easily measurable marker reflecting hepatic fibrosis. Recently, FIB-4 index has been reported to be associated with cardiac events in heart failure (HF) patients. We examined whether FIB-4 index was useful in predicting elevated right atrial pressure (RAP) in comparison with directly measured RAP. Methods We studied consecutive 293 HF patients who underwent right heart catheter (RHC) examinations at our institution between Sep 2021 and May 2023. The exclusion criteria were as follows: viral or metabolic chronic hepatic diseases, thrombocytopenia. The subjects received RHC examination and blood test on the same day, and echocardiography within 3 days from the RHC examination. On top of FIB-4 index, diameter of inferior vena cava (IVC) and its respiratory changes were measured as a conventional method to estimate RAP. Results A total of 252 patients (mean 64.7 years of age, 52.8% men) were eligible for this study. FIB-4 index was significantly correlated with mean RAP (r = 0.39, p < 0.001). ROC curve analysis revealed that 1.80 was the optimal cutoff value of FIB-4 index to predict increased RAP > 10mmHg (AUC 0.74, p < 0.001, sensitivity 76.1%, specificity 74.0%). As shown in Figure, the diagnostic accuracy increased when FIB-4 index was combined with IVC diameter (AUC 0.77), which was significantly higher than the combination (AUC 0.71) of IVC diameter alone (AUC 0.71, p < 0.001, cutoff 17mm, sensitivity 67.6%, specificity 71.8%) and IVC respiratory changes alone (AUC 0.61, p = 0.005, cutoff 53%, sensitivity 77.5%, specificity 44.2%). Conclusions FIB-4 index was clinically useful in predicting increased RAP, especially when it was combined with IVC diameter.