Comparison of midregional pro-atrial and B-type natriuretic peptides in chronic heart failure: influencing factors, detection of left ventricular systolic dysfunction, and prediction of death.

OBJECTIVES: Midregional pro-atrial natriuretic peptide (MR-proANP) was assessed for the importance of influencing factors, the ability to detect left ventricular systolic dysfunction, and the prognostic power compared with B-type natriuretic peptide (BNP) and amino-terminal pro-B-type natriuretic peptide (NT-proBNP) in chronic heart failure (HF).

BACKGROUND: MR-proANP is a biologically stable natriuretic peptide measured by a recently developed assay, with potential advantages over conventional natriuretic peptides such as BNP and NT-proBNP.

METHODS: We measured MR-proANP, BNP, and NT-proBNP in 797 patients with chronic HF.

RESULTS: All 3 natriuretic peptides were independently influenced by left ventricular ejection fraction (LVEF), glomerular filtration rate (GFR), and the presence of ankle edema. Area under receiver-operator characteristic curves for detection of an LVEF <40% were similar between MR-proANP (0.799 [95% confidence interval (CI): 0.753 to 0.844]), BNP (0.803 [95% CI: 0.757 to 0.849]), and NT-proBNP (0.730 [95% CI: 0.681 to 0.778]). During a median observation time of 68 months, 492 (62%) patients died. In multiple Cox regression analysis each natriuretic peptide was the strongest prognostic parameter among various clinical variables. Proportion of explained variation showed that NT-proANP (4.36%) was a significantly stronger predictor of death than both NT-proBNP (2.47%, p < 0.0001) and BNP (2.42%, p < 0.0001).

CONCLUSIONS: Despite similarities in influencing factors and detection of reduced LVEF, MR-proANP outperformed BNP and NT-proBNP in the prediction of death. A new assay technology and the high biological stability of MR-proANP are potential explanations for these findings.