Midregional Pro-Atrial Natriuretic Peptide and Outcome in Patients With Acute Ischemic Stroke

Objectives The purpose of this study was to examine the prognostic value of midregional pro-atrial natriuretic peptide (MR-proANP) in patients with acute ischemic stroke. Background The rapid and reliable estimation of prognosis in acute ischemic stroke is pivotal to optimize clinical care. MR-proANP, a recently described, stable fragment of the ANP precursor hormone, may be useful in this setting. Methods In a prospective observational study, we measured MR-proANP on admission in plasma of 362 consecutive patients presenting with acute ischemic stroke. The prognostic value of MR-proANP to predict mortality within 90 days and functional outcome (defined as a modified Rankin Scale of ≤2 or ≥3) was evaluated and compared with the National Institutes of Health Stroke Scale (NIHSS) score. Results The discriminatory accuracy, calculated with the area under the curve (AUC) of the receiver operating characteristics curve, of MR-proANP to predict death was comparable to the NIHSS (AUC: 0.86 [95% confidence interval (CI): 0.82 to 0.90] and 0.85 [95% CI: 0.81 to 0.89; p = 0.7]). Combined, the accuracy significantly improved (0.92 [95% CI: 0.88 to 0.96; p < 0.01]). The AUC of MR-proANP to predict functional outcome was 0.70 (95% CI: 0.65 to 0.75), similar to the NIHSS (0.75 [95% CI: 0.70 to 0.80]; p = 0.16). The prognostic value of MR-proANP for both outcomes was independent of the NIHSS. Higher MR-proANP concentrations were found in stroke of cardioembolic etiology. Conclusions MR-proANP is a prognostic marker in the acute phase of stroke, improving the discriminatory value of the NIHSS, independently predicting post-stroke mortality and functional outcome. (The "COSMOS"-Study [Copeptin in Osmoregulation and Stress Assessment]; NCT00390962).