Comparison of midregional pro-atrial natriuretic peptide with N-terminal pro-B-type natriuretic peptide in predicting survival in patients with chronic heart failure.

OBJECTIVES Our aim was assess the prognostic value of midregional pro-atrial natriuretic peptide (MR-proANP) using a new immunoassay in patients with chronic heart failure (HF). BACKGROUND Assessment of natriuretic peptides represents a useful addition in establishing the diagnosis of chronic HF. Their plasma values are powerful predictors of survival in chronic HF. METHODS We assessed MR-proANP in 525 chronic HF patients (derivation study: age 61 +/- 12 years, New York Heart Association (NYHA) functional class I/II/III/IV 6%/44%/41%/9%, N-terminal pro-B-type natriuretic peptide (NT-proBNP) 3,637 +/- 6,362 pg/ml) and validated our findings in 249 additional chronic HF patients (age 63 +/- 9 years, NYHA functional class I/II/III/IV 14%/50%/33%/3%, NT-proBNP 1,116 +/- 1,991 pg/ml). RESULTS The MR-proANP levels (mean 339 +/- 306 pmol/l, range 24.5 to 2,280 pmol/l) increased with NYHA functional class (p < 0.0001). During follow-up (>6 months in survivors), 171 patients (33%) died. Increasing MR-proANP was a predictor of poor survival (risk ratio 1.35 per increase in standard deviation, 95% confidence interval 1.17 to 1.57; p = 0.0061), adjusted for NT-proBNP, age, left ventricular ejection fraction, NYHA functional class, creatinine, and body mass index (BMI). In receiver operating characteristic curve analysis of 12-month survival, the area under the curve for MR-proANP was 0.74 and that of NT-proBNP was 0.75 (p = 0.7). In a validation study, MR-proANP levels above the optimal prognostic cutoff value from the validation cohort remained a significant independent predictor of death. In chronic HF patients in NYHA functional class II to III and all subgroups of BMI and kidney function, MR-proANP added prognostic value to NT-proBNP. In patients with BMI > or =30 kg/m2, MR-proANP had higher prognostic power than NT-proBNP. CONCLUSIONS Midregional proANP is an independent predictor of mortality in patients with chronic HF. Midregional proANP adds prognostic information to NT-proBNP.