B-type natriuretic peptide in hypertensive crises: Diagnostic use in hypertensive urgencies and emergencies

It is not so easy to make a quick screening between hypertensive emergency (HE) and hypertensive urgency (HU), as it often requires sophisticated, complex and time consuming clinical, instrumental and diagnostic tests. To address the role of B-type natriuretic peptide (BNP) in hypertension and how to use it to differentiate HE from HU to alleviate possible complications. A total of 30 patients with rapid severe elevation of blood pressure (BP) admitted to the in-patient wards and critical care department, Cairo University, were included in a prospective, non-interventional study. On the basis of the clinical findings, patients were subdivided into two groups: Group I: 15 patients with HE with acute organ involvement and group II: 15 patients with HU without acute organ damage. Another 10 patients with chronic hypertension were taken as control group. BNP was measured in the blood at the time of admission based on the principle of competitive enzyme immunoassay. There was no significant correlation between the patients’ age (58.5 ± 12) and BNP level (183.67 ± 216.3) (r = −0.17, p = 0.3) and also there was no significant difference in BNP blood level between males (223.35 ± 179.2) and females (131.77 ± 255.2) (p = 0.26) and it was significantly higher in HE patients (324.33 ± 233.16) than HU patients (43 ± 13.5) and control group (8.13 ± 5.8) with p-value of <0.001. There was no significant difference in BNP level between HE patients with cardiac (313.33 ± 179.6) and neurological involvement (313.67 ± 273.5) (p = 0.8), also, there was no significant difference in BNP level between patients presented with ischemic stroke (248.75 ± 171), hemorrhagic stroke (255 ± 132) and hypertensive encephalopathy (970) (p = 0.3). Moreover, there was no significant correlation between BNP and systolic BP, diastolic BP, mean arterial pressure and pulse pressure in both studied patients and control groups (p > 0.05 in all). Receiver operator characteristic (ROC) curve was calculated for the use of BNP level as a diagnostic marker. The area under curve (AUC) for BNP as a diagnostic marker was 0.96. During hypertensive crises BNP blood level determination could have a role as a diagnostic tool for the screening of HE and its evaluation is very useful in patients admitted with acute and rapid elevation of BP to limit target organ damage.