Association of Plasma Brain Natriuretic Peptide Levels in Acute Ischemic Stroke Subtypes and Outcome

Background: Brain natriuretic peptide (BNP) is believed to be a diagnostic marker for cardiovascular diseases, including atrial fibrillation (AF). Recent studies have incriminated BNP as a marker of cardioembolic stroke. We aimed at investigating association of plasma BNP levels in acute ischemic stroke subtypes and their outcome in Indian patients. Methods: We recruited 270 acute ischemic stroke patients within 48 hours of symptom onset and compared with 110 age- and sex-matched control subjects. This study was carried out at Yashoda Hospital, Hyderabad, India between April 2011 and March 2013. Serum BNP levels were estimated in stroke patients and control subjects. Good functional outcome at 3 months was defined as modified Rankin score (mRS) 2 or less. Results: Elevated BNP levels was significantly more in patients with acute ischemic stroke patients 119 (44%) compared with controls 4 (3.6%; P < .0001). Among stroke subtypes, elevated BNP levels were observed in 75% of cardioembolic strokes, 45.8% of small artery disease, 43.1 % of larger artery atherosclerosis, and 34.5% of stroke of undetermined etiology. On multiple logistic regression analysis, elevated BNP levels were significantly associated with acute ischemic stroke (odds ratio [OR], 13.0; 95% confidence interval [CI], 8.1-15.4). Among stroke subtypes, significant association was seen with cardioembolic stroke (OR, 3.5; 95% CI, 2.2-7.2). Elevated BNP levels were independently associated with poor outcome (OR, 3.4; 95% CI, 1.2-13.7; P < .0001) and higher mortality (OR, 3.4; 95% CI, 1.2-13.7; P < .0001). Conclusions: Elevated BNP level is an independent marker for cardioembolic stroke and poor outcome at 90 days follow-up. No significant association was seen with other stroke subtypes.