The correlation between Fischer’s ratio and the risk of cardiac dysfunction in Systolic Heart Failure

Abstract Backgrounds: Due to the high mortality and hospitalization rate in chronic heart failure (HF), it is of great significance to study myocardial nutrition conditions. Amino acids (AAs) are essential nutrient metabolites for cell development and survival. This study aims to investigate the plasma branched-chain amino acid/aromatic amino acid ratio (Fischer’s ratio, FR) as a potential metabolic risk factor for the presence of chronic HF and left ventricular (LV) pressure filling. Methods The value of serum AAs was obtained from 441 cardiovascular subjects by liquid chromatography-tandem, and 213 systolic HF subjects were followed up for a mean year (11.74 ± 1.44 months). LV ejection fraction (EF) and the ratio of early diastolic mitral inflow to mitral annular tissue velocities (E/e’) were determined by two-dimensional echocardiography and Doppler flow imaging using standard biplane technique. Logistic regression analysis was conducted to measure the FR index and the risk of HF, and further confirmed by receiver-operating characteristic curves (ROC curve) analysis. The event-free HF endpoint was determined by Kaplan–Meier curves, and differences were assessed using log‐rank tests. Results FR index decreased gradually along with the control group, systolic HF with E/e’≤14 group, and systolic HF with E/e’>14 group (3.73 ± 1.20 vs. 3.45 ± 0.94 vs. 3.18 ± 0.83, respectively, P < 0.001). Low FR index was associated with systolic HF after full adjustment in all subjects [odds ratio (OR), 2.124; 95% confidence interval (CI): 1.595–2.829; P < 0.001] and the area under the curve (AUC) of ROC curve was 0.722 (sensitivity 62.91%, specificity 78.95%). Meanwhile, low FR index was the independent risk of E/e’>14 for systolic HF (OR: 1.525; 95% CI: 1.053–2.209; P = 0.025). The AUC of ROC curve for predicting abnormal E/e’ was 0.732 (sensitivity 61.39%, specificity 75.68%) by multivariate logistic regression. Furthermore, the decreased FR values indicated poor prognosis in systolic HF subjects (Log-rank P = 0.005). Conclusions In all subjects, low FR confers an increased risk for predicting systolic HF. Decreased FR levels could also indicate increased LV filling pressure in systolic HF. In addition, a lower FR value was associated with higher HF endpoint events. Thus, FR can be a valuable indicator of heart function.