Assessment of Brain Natriuretic Peptide Levels in Patients Presenting to the Emergency Department With High Blood Pressure

Objective: Hypertension is one of the leading causes of cardiovascular morbidity and mortality worldwide. Although patients presenting to emergency departments (EDs) with high blood pressure (BP) are frequently seen, it is difficult to distinguish patients with true hemodynamic or cardiac stress. Brain natriuretic peptide (BNP), secreted in response to ventricular wall strain, may serve as a useful biomarker. This study was conducted to evaluate BNP levels in patients presenting to the ED with high BP and to examine their relationship with systolic and diastolic pressures according to the antihypertensive treatment status. Methods: This single-center, prospective study included 204 adults who presented with systolic BP ≥140 mmHg and/or diastolic BP ≥90 mmHg between July 2012 and December 2012. Patients with heart or kidney failure, acute coronary syndrome, or pregnancy were excluded from the study. Plasma BNP was measured using a chemiluminescent immunoassay. Participants were grouped according to antihypertensive medication use, and BNP levels were compared with BP values. Results: The median BNP level was 79.4 pg/mL (range: 9.1-3500). BNP showed a moderate correlation with diastolic blood pressure (DBP) (r = 0.523; p < 0.001) but did not correlate with systolic blood pressure (SBP) or pulse rate (p > 0.05). BNP levels were higher in untreated patients than in treated patients (median: 259.5 and 67.7 pg/mL, p < 0.001). No significant difference was observed between drug classes. DBP was the only independent predictor of BNP. Conclusion: BNP levels were significantly higher in patients not receiving regular antihypertensive treatment, particularly in those with higher DBP. BNP measurement in selected ED cases may provide additional information regarding hemodynamic stress; however, larger multicenter studies are needed to clarify its clinical utility and determine whether practical thresholds can be defined.