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Falling Blood Pressure in Early Acute Stroke: A Sign of Poor Prognosis

Large declines in blood pressure during the first 24 hours after stroke predicted poor outcomes in 2 observational studies.

Management of hypertension during acute stroke is controversial. Although blood pressure lowering might be hazardous immediately after stroke onset, physicians sometimes find it hard to resist treating substantially elevated BPs in this setting. In 2 studies, researchers examined associations between BP changes and outcomes in patients with acute stroke.

Brazilian researchers prospectively followed 115 patients with acute ischemic strokes. Mean BP on admission was 160/94 mm Hg (range, 110/60 to 260/170 mm Hg); systolic BP decreased by an average of 28 mm Hg during the first 24 hours. In multivariable analysis, a larger fall in systolic BP during the first 24 hours independently predicted a higher probability of severe stroke-related disability at 3 months. Antihypertensive drug therapy (given to 59% of patients during the first 24 hours) neither correlated with systolic BP reductions nor predicted poor outcomes.

Austrian researchers studied 372 acute ischemic-stroke patients with average BPs similar to those in the Brazilian study. In multivariable analysis, a 25% decrement in diastolic BP during the first hospital day was associated with increased risk for poor neurologic outcome on day 5, independent of diastolic BP at admission. As in the Brazilian study, antihypertensive drug therapy (given to 32% of patients during the first day) was not associated with BP reductions or neurologic outcomes.

Comment: Both studies demonstrate a relation between early decrease in BP and poor neurologic outcome among patients with acute ischemic stroke, but cause and effect remains unclear. Although early antihypertensive therapy seemed neither beneficial nor harmful, we can't distinguish with certainty between drug effects and spontaneous BP changes in these observational studies. For now, clinicians should consider following a recently published guideline that suggests a threshold of 220/120 mm Hg for initiating antihypertensive therapy in most patients with acute ischemic stroke. Lower thresholds are appropriate for patients with other end-organ complications that mandate BP lowering and for patients who are eligible for thrombolytic therapy.

— Allan S. Brett, MD

Published in Journal Watch General Medicine November 28, 2003

Citation(s):

Oliveira-Filho J et al. Detrimental effect of blood pressure reduction in the first 24 hours of acute stroke onset. Neurology 2003 Oct 28; 61:1047-51.

• Original article (Subscription may be required)
• Medline abstract (Free)

Vlcek M et al. Association between course of blood pressure within the first 24 hours and functional recovery after acute ischemic stroke. Ann Emerg Med 2003 Nov; 42:619-26.

• Medline abstract (Free)