Relation of natriuretic peptides and midregional proadrenomedullin to cardiac chamber volumes by computed tomography in patients without heart failure: from the ROMICAT Trial.

BACKGROUND: Stress myocyte biomarkers are used prognostically in patients with cardiovascular disease. We examined associations between amino-terminal pro-B-type natriuretic peptide (NT-proBNP), midregional pro-A-type natriuretic peptide (MR-proANP), and midregional proadrenomedullin (MR-proADM) concentrations and cardiac chamber volumes in chest pain patients without heart failure by use of computed tomography (CT).
METHODS: At the time of 64-slice CT scan, we acquired plasma and serum samples for these biomarkers from 346 patients [mean (SD) age 53 (12) years, 65% men]. Left atrial volume (LAV) and left ventricular volumes at end-diastole (LVEDV) and end-systole (LVESV) were measured and indexed to body surface area (LAVI, LVEDI, LVESI).
RESULTS: Concentrations of both natriuretic peptides were correlated with LAV and LAVI (r = 0.19-0.32, all P <or= 0.0005) and MR-proADM with LV volumes and indices (r = -0.14 to -0.21, all P <or= 0.01). NT-proBNP and MR-proANP concentrations were higher in the top quartiles of patients than the lowest quartiles using LAV and LAVI, whereas MR-proADM concentrations were lower in the top quartiles of LV measures. In adjusted analyses, patients had 2- to 4-fold increased risk of LA enlargement for every incremental increase in log(10)NT-proBNP [LAV odds ratio (OR) 2.4, P = 0.03; LAVI OR 4.0, P = 0.003] and 10- to 13-fold increased risk of LA enlargement for every incremental increase in log(10)MR-proANP (LAV OR 10.7, P = 0.009; LAVI OR 13.1, P = 0.004).
CONCLUSIONS: In patients without heart failure, both NT-proBNP and MR-proANP concentrations are independently associated with LA enlargement, whereas MR-proADM concentrations are correlated with LV volumes. This may partially explain the well-recognized value of natriuretic peptides for use in risk stratification.