Introduction: NT-proBNP values vary inversely with glomerular filtration rate (GFR) in patients with as well as without heart failure (HF). There are few data abo-ut the factors affecting plasma concentration of NT-proBNP or about the diagnostic value of NT-proBNP in HF associated with advanced chronic kidney disease (CKD).
Objectiv: To analyze the clinical and biological para-meters associated with elevated NT-proBNP values in patients with IC and severe renal impairment, expre-ssed by GFR <30 ml/min/1,73m².
Methods: Patients with HF admitted to our clinic from January 2011 to December 2014 were retrospectively enrolled in this study. From 1058 patients, we selec-ted the ones with GFR <30 ml/min/1.73m² calculated with CKD-EPI using serum creatinine from admission. Acute coronary syndromes, neoplasms, acute pulmo-nary embolisms and systemic infections were exclusion criteria.
Results: Our sample consisted of 63 patients with a mean age of 76.5±9.5 years. 53.97% were women. 26.5% had NYHA class IV. 68.33% presented with acu-te decompensated heart failure (ADHF). NT-proBNP had higher median values in patients with ADHF than chronic stable heart disease (6391.5 vs. 1496 pg/ml, p<0.001), patients with dyspnea at rest than witho-ut it (14406 vs. 2352 pg/ml, p=0.006) and in patients with reduced ejection fraction (EF) than those with mid-range EF and preserved EF who had similar va-lues (10036 vs. 1838 vs. 1706 p/ml, p=0.02). Age, gen-der, obesity, diabetes mellitus, ischemic heart disease and atrial fibrillation were not associated with signi-ficant differences of NT-proBNP levels. NTproBNP values correlated directly with NYHA class(r=0.451, p=0.001) and inversely with EF (r=-0.496, p<0.001) and hemoglobin(r=-0.291, p=0.029). NT-proBNP did not correlate with GFR (probably because of the extre-me severity of kidney disease and small GFR variabi-lity). ROC curve analysis proved NT-proBNP to be a good predictor of ADHF, (AUC=0.803 (95%CI 0.677-0.896), p<0.001). Cut-off value obtained through You-den index associated criterion was >4141 pg/ml, with a sensibility of 67.5% and a specificity of 83.33%.
Conclusions: In patients with advanced kidney disease (GFR <30 ml/min/1.73m²), NT-proBNP values corre-late with HF parameters (NYHA class IV, acute decom-pensation of HF and reduced EF) and do not correlate with other comorbidities – that classically affect NT-proBNP variability in HF (gender, obesity, diabetes mellitus, atrial fibrillation, ischemic heart disease).