Ambulatory blood pressure monitoring and stroke: more questions than answers

Prognostic value of blood pressure in acute stroke

Manipulation of blood pressure (BP) in acute stroke may improve outcome. Despite various studies, data on the prognostic significance of early BP in stroke remain unclear. Therefore, we studied the relationship between various BP variables in the acute phase of stroke and functional outcome at 3 months. Blood pressures were collected by reviewing BP records of 817 patients who were admitted to our stroke unit between 1987 and 1992. Besides the first systolic and diastolic admission BP (SBP and DBP), we also used the mean of the daytime as well as the night-time systolic and diastolic BP values. Finally, we studied the relationship between the decrease in BP between day 0 and 4 and outcome. As dependent outcome variable we used the Rankin handicap score at 3 months dichotomized in a score >3 (poor outcome) vs a score 3 (good outcome). A total of 430 patients were admitted within 24 h following stroke onset. There was no significant relationship between the systolic and diastolic BP and the outcome at 3 months. Only night-time systolic BP 165 mm Hg (odds ratio (OR) 2.8; 95% CI 1.1-6.8), night-time diastolic BP 60 mm Hg (OR 8.1; 95% CI 1.1-58.3), and a decrease in daytime diastolic BP between day 0 and 4 of 10 mm Hg (OR 3.0; 95% CI 1.1-7.9) showed a significant relationship with poor outcome. Our findings suggest that admission BP values may not reliably reflect any impact of BP on stroke outcome. They also suggest a potential differential effect of BP manipulation: increasing or decreasing BP may be beneficial for patients with BP extremes in one direction, but detrimental for those with BP values in the opposite direction.