Lethal risk index — a novel tool for predicting one-year mortality in patients with heart failure with reduced ejection fraction

Aim . To develop criteria for predicting one-year mortality in patients with heart failure with reduced ejection fraction (HFrEF) after cardioverter defibrillator implantation for sudden cardiac death primary prevention. Material and methods . The full study protocol was completed by 451 patients with HFrEF referred for cardioverter defibrillator implantation for primary prevention of sudden cardiac death. The study participants underwent preimplantation clinical and paraclinical screening, as well as 12-month prospective follow-up to assess one-year mortality due to cardiovascular events. To solve the problem, training and test samples were formed. Results . One-year mortality due to cardiovascular events in the training group were registered in 35 patients (11%). Univariate analysis identified 6 factors with the highest prognostic potential (p<0,1) associated with the studied endpoint. These included clinical data (history of hypertension and/or obesity), echocardiographic (left ventricular ejection fraction <25%, eccentric left ventricular myocardial hypertrophy) and laboratory parameters (glomerular filtration rate <60 ml/min/1,73 m 2 , N-terminal pro-brain natriuretic peptide >2000 pg/ml). Based on the regression coefficients, each factor was assigned points, the sum of which determined the original lethal risk index (LRI) value. LRI >3 allow predicting the one-year cardiovascular death probability in patients with heart failure with a sensitivity of 85,7% and a specificity of 76,8%. LRI in patients of the test sample demonstrated very good quality of the model in predicting the risk of one-year cardiovascular mortality (AUC 0,852±0,069 with 95% confidence interval: 0,716-0,988; p=0,0001). Conclusion . Based on the obtained data, a LRI was developed, the practical application of which is aimed at improving the provision of health care and developing a risk-oriented strategy for managing patients with HFrEF.