Relation between brain natriuretic peptide and delayed cerebral ischemia in patients with aneurysmalsubarachnoid hemorrhage

Brain natriuretic peptide (BNP), often used to evaluate degree of heart failure, has been implicated in fluid dysregulation and inflammation in critically-ill patients. Twenty to 30% of patients with aneurysmal subarachnoid hemorrhage (aSAH) will develop some degree of neurogenic stress cardiomyopathy (NSC) and in turn elevation of BNP levels. We sought to explore the association between BNP levels and development of delayed cerebral ischemia (DCI) in patients with aSAH. We retrospectively evaluated the records of 149 patients admitted to the Neurological Intensive Care Unit between 2006 and 2015 and enrolled in an existing prospectively maintained aSAH database. Demographic data, treatment and outcomes, and BNP levels at admission and throughout the hospital admission were noted. Of the 149 patients included in the analysis, 79 developed DCI during their hospital course. We found a statistically significant association between DCI and the highest recorded BNP (OR 1.001, 95% CI-1.001–1.002, p = 0.002). The ROC curve analysis for DCI based on BNP showed that the highest BNP level during hospital admission (AUC 0.78) was the strongest predictor of DCI compared to the change in BNP over time (AUC 0.776) or the admission BNP (AUC 0.632). Our study shows that DCI is associated not only with higher baseline BNP values (admission BNP), but also with the highest BNP level attained during the hospital course and the rapidity of change or increase in BNP over time. Prospective studies are needed to evaluate whether routine measurement of BNP may help identify SAH patients at high risk of DCI.