Acute blood pressure levels and long-term outcome in ischemic stroke.

OBJECTIVES

Elevated blood pressure (BP) is common in acute ischemic stroke, but its effect on outcome is not fully understood. We aimed to investigate the association of baseline BP and BP change within the first day after stroke with stroke severity, functional outcome, and mortality.

METHODS

Patients admitted to hospital with acute ischemic stroke (IS) from 15 February 2005 through 31 May 2009 were consecutively included. Acute stroke severity and functional outcome at three and twelve months were investigated using multivariate regression analysis; the association between BP and all-cause mortality at one, three, and twelve was investigated by Cox proportional hazard regression and Kaplan-Meier survival curves.

RESULTS

A total of 799 patients (mean age 78.4 ± 8.0, 48% men) were included. Higher decreases in systolic and mean arterial blood pressure (ΔSBP and ΔMAP) were associated with decreased 1-month mortality (ΔSBP: hazard ratio, HR: 0.981; 95% CI: 0.968 - 0.994; p = .005), 3-month mortality (ΔSBP: HR 0.989; 95% CI 0.981 - 0.998; p-value .014), and twelve-month mortality (ΔSBP: HR 0.989; 95% CI 0.982 - 0.996; p-value .003). Stroke severity was associated with ΔMAP (B coefficient -.46, p-value .011). Higher SBP and MAP on admission were associated with better functional outcome at three (SBP: OR 0.987; 95% CI 0.978 - 0.997; p-value .008 - MAP: OR 0.985; 95% CI 0.971 - 1; p-value .046) and twelve (SBP: OR 0.988; 95% CI 0.979 - 0.998; p-value .015 - MAP: OR 0.983; 95% CI 0.968 - 0.997; p-value .02) months.

CONCLUSION

In this elderly population, higher BP on arrival to the emergency room (ER) and decrease in BP after the patients' arrival to the ward were associated with improved functional outcome and reduced mortality, respectively. These results may reflect a regulatory situation in which elevated initial blood pressure indicates adequate response to cerebral tissue ischemia while subsequent blood pressure decrease instead may be a consequence of partial, successful reperfusion.