Brain edema formation is associated with the time rate of blood pressure variation in acute stroke patients

Objectives Both brain edema and increased blood pressure (BP) variability are associated with poor outcome after stroke. The aim of the present study was to evaluate a possible association between edema formation and a relatively new index of BP variability defined as time rate (TR) of BP variation.Patients and methods A total of 128 first-ever acute stroke patients underwent 24-h ambulatory BP monitoring within 24 h from onset of stroke. All patients were imaged with computed tomography scan on admission and after 5 days to determine the presence of brain edema. The TR of BP variation was defined as the first derivative of the BP values against time. Known risk factors and neurological severity on admission were documented.Results The 24-h TR of systolic BP variation was significantly higher (P<0.001) in stroke patients with brain edema (0.69 +/- 0.15 mmHg/min) compared with those without edema (0.57 +/- 0.12 mmHg/min). The multivariate logistic regression model showed that a 0.1 mmHg/min increase in the TR of 24-h systolic BP variation was associated with a 13.9% increased probability of the presence of brain edema (odds ratio=1.139, 95% confidence interval: 1.058-1.225, P<0.001), after adjusting for history of diabetes mellitus, hypercholesterolemia, type of stroke, neurological deficit, and 24-h systolic BP.Conclusion Increased values of 24-h TR of systolic BP variation are associated independently with formation of edema in acute stroke patients. (C) 2013 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins.