Abstract 3748: MR-pro Midregional Pro-Atrial Natriuretic Peptide and Risk of Cardiovascular Death in Coronary Artery Disease
Background: Atrial natriuretic peptide as a member of the natriuretic peptide family has been shown to be associated with cardiovascular (CV) outcome. In direct comparisons, (N-terminal pro) B-type natriuretic peptide has been a stronger risk indicator. The new immunolumino-metric assay available for the measurement of midregional-proANP (MR-proANP) allows the determination of the more stable analyte. The aim of this study was to assess the power of MR-proANP to predict CV mortality in comparison with BNP.
Methods: Baseline concentrations of MR-proANP and Nt-proBNP were measured in 2251 patients presenting to the coronary unit (1334 patients with stable angina (SAP) and 864 patients with acute coronary syndrome (ACS)). Follow-up information on cardiovascular death was available in 2198 patients (97.6%). During a median follow-up of 3.6 years 103 CV deaths were documented.
Results: Median MR-proANP concentrations were higher in patients presenting with ACS 93.45 pmol/L (65.925/149.75; 25th/75th interquartile range) vs. 89.75 pmol/L (59.55/143.0) in SAP patients; p=0.016. Similarly MR-proANP measurements were significantly higher in patients with future CV mortality (166.0 pmol/L (88.7/289.0)) compared to patients free of events (89.8 pmol/L (61.2/140.0)) (p<0.0001). Kaplan Meier survival curves revealed a stepwise decrease of event-free survival with increasing quartiles of MR-proANP (Plog rank30.0001). Log-transformed MR-proANP concentrations were significantly associated with cardiovascular mortality (Hazard ratio (HR) (95% confidence interval) 3.191 (2.38 – 4.29), p<0.0001). This association remained robust after adjustment for classical risk factors, C-reactive protein and even Nt-proBNP (HR 1.79 (1.19 –2.6); p=0.005). The relative risk of mortality for patients in the upper quartile was 3.93-fold increased (95%CI 2.04 –7.55; p<0.0001) compared to the first quartile. This association also remained significant after adjustment for potential confounders.
Conclusion: Baseline concentrations of MR-proANP are strongly associated with cardiovascular death during long-term follow up in patients suffering from CAD. This association remained stable after adjustment for potential clinical and neurohumoral confounders.