Cerebrovascular risks with rapid blood pressure lowering in the absence of hypertensive emergency

In the Emergency Department (ED) setting, clinicians commonly treat severely elevated blood pressure (BP) despite the absence of evidence supporting this practice. We sought to determine if this rapid reduction of severely elevated BP in the ED has negative cerebrovascular effects.

This was a prospective quasi-experimental study occurring in an academic emergency department. The study was inclusive of patients with a systolic BP (SBP) > 180 mm Hg for whom the treating clinicians ordered intensive BP lowering with intravenous or short-acting oral agents. We excluded patients with clinical evidence of hypertensive emergency. We assessed cerebrovascular effects with measurements of middle cerebral artery flow velocities and any clinical neurological deterioration.

There were 39 patients, predominantly African American (90%) and male (67%) and with a mean age of 50 years. The mean pre-treatment SBP was 210 ± 26 mm Hg. The mean change in SBP was -38 mm Hg (95% CI -49 to -27) mm Hg. The average change in cerebral mean flow velocity was -5 (95% CI -7 to -2) cm/s, representing a -9% (95% CI -14% to -4%) change. Two patients (5.1%, 95% CI 0.52-16.9%) had an adverse neurological event.

While this small cohort did not find an overall substantial change in cerebral blood flow, it demonstrated adverse cerebrovascular effects from rapid BP reduction in the emergency setting.