Abstract 32: N-terminal Probrain Natriuretic Peptide Shows Diagnostic Accuracy For Atrial Fibrillation
Introduction: The diagnosis of paroxysmal atrial fibrillation (pAF) in patients with stroke is of paramount importance and has therapeutic implications. However identifying pAF can be difficult. N-terminal probrain natriuretic peptide (NT-proBNP),a peptide produced by the heart, may be useful to identify pAF in patients with cryptogenic stroke.
Hypothesis: Cut-off points of serum NT-proBNP at the time of stroke onset can help identify pAF in cryptogenic stroke patients.
Methods: Among 263 ischemic stroke patients admitted to a stroke unit NT-proBNP serum levels were measured within 72 hours of stroke onset. Etiological evaluation included: TTE, ECG and 24-Holter. Etiology was classified using TOAST criteria. In patients with cryptogenic stroke, 24-Holter was done to look for pAF within the first week, three and six months after admission. First, patients with a defined etiology were used to construct a Receive Operating Characteristic (ROC) curve for the diagnosis of AF. From this curve, the sensitivity and specificity of pre-established cut-off points was calculated. A logistic regression was done to assess the independent relationship of lnNT-proBNP with AF controlling for confounders. In a second phase the cut-off points previously established were evaluated, in patients with cryptogenic stroke, for the diagnosis of pAF.
Results: In 179 patients a stroke etiology could be established. Fifty five patients had the diagnosis of cardioembolic stroke related to AF. Using multivariate analysis the lnNT-proBNP was independently associated to AF (OR - 2.7, 95% CI 1.5-4.8; p=0.01). The Area Under the Curve (AUC) of the ROC curve of lnNT-proBNP for the diagnosis of AF was excellent - 0.91, 95% CI (0.87-0.95). The previously defined cut-off of 265.5 pg/ml had a sensitivity of 100% and specificity of 72.6%. The cut-off point of 912 pg/ml had a specificity of 87.9%. 83 patients had a cryptogenic stroke. In 16 (19%) pAF was found during follow-up. The cut-off point of 265.5 pg/ml had a sensitivity of 93.8% and a specificity of 58.8% for the diagnosis of pAF. The cut-off point of 912 pg/mL had a specificity of 88.2%.
Conclusion: NT-proBNP had good accuracy to predict pAF in patients with cryptogenic stroke and can help evaluate these patients.
- © 2012 by American Heart Association, Inc.