Nt-proBNP in haemodialysis patients: a preliminary study.

Abstract:

OBJECTIVE: N-terminal pro-brain natriuretic peptide (Nt-proBNP) is a marker of left ventricular function. Although many factors can increase left ventricular dysfunction in haemodialysis patients, the role of Nt-proBNP is uncertain. MATERIAL AND METHODS: Serum concentrations of Nt-proBNP and troponin T were measured by electrochemiluminescence and C-reactive protein by immunoturbidimetry in 52 dialysis patients followed-up for 36 months. RESULTS: Nt-proBNP correlated (p<0.05) with time on haemodialysis (rho=0.345), left ventricular mass index (r=0.596), troponin T level (r=0.605) and age (r=0.296). Patients with a history of heart disease showed higher levels of Nt-proBNP (median; minimum-maximum ngl/L) (15,571; 1,553-209,451) than those without (4,535; 751-115,078) (p<0.01). Sensitivity and specificity of Nt-proBNP in the detection of left ventricular dysfunction (ventricular ejection fraction < 45%) were 1.0 and 0.782, respectively. In the univariate analysis, patients with Nt-proBNP levels > or = 33,314 ng/L, CRP > or = 5 mg/L or troponin T > or = 0.1 microg/L had poorer probabilities of 1-year, 2-year and 3-year survival than patients with lower levels. Unfavourable prognostic factors in the multivariate analysis were CRP > 5 mg/L and Tn T > 0.1 microg/L. CONCLUSIONS: Nt-proBNP showed good diagnostic performance for detecting left ventricular dysfunction and was an important predictor of mortality in haemodialysis patients in the univariate analysis. In the multivariate analysis, Nt-proBNP lost its prognostic value, whereas for CRP and Tn T it was maintained.