Association between 24-h blood pressure monitoring variables and brain oedema in patients with hyperacute stroke

Abstract

OBJECTIVE: To assess the effects of blood pressure (BP) values on oedema formation following hyperacute stroke. DESIGN: Prospective observational study. SETTING AND PATIENTS: Acute stroke-unit in University hospital. A total of 240 consecutive first-ever ischaemic or haemorrhagic stroke patients were recruited within 3 h of ictus. METHODS Casual and 24-h BP values were measured. Known stroke risk factors and clinical findings on admission were documented. Patients were imaged with computed tomography (CT) scan within 24 h from stroke onset and 5 days later in order to determine the presence of brain oedema. Patients who received antihypertensive medication during the BP monitoring were excluded. RESULTS: The main outcome measure was brain oedema formation, which was present in 78 (32.5%) patients. The 24-h systolic (SBP), diastolic (DBP) and mean BP values, 24-h pulse pressure and heart rate values were significantly higher in patients with brain oedema than in the reference group (stroke patients without brain swelling). On multiple variable analysis, containing clinical, demographic and BP monitoring variables, 24-h SBP remained significantly (P = 0.019) associated with brain oedema. The odds ratio for oedema formation associated with each 10-mmHg increase in 24 h SBP was 1.25 (95% confidence intervals: 1.04-1.51). During the first 27 h after onset SBP course showed a spontaneous decline in the reference group, which was not documented in patients with brain oedema. CONCLUSION: Elevated 24-h SBP values in the acute stroke period are associated with subsequent brain oedema formation.