Factors affecting changes in blood pressure after acute stroke.

BACKGROUND AND PURPOSE

We sought to establish the pattern of blood pressure (BP) change after hospitalization for acute hemispheric stroke.

METHODS

In 292 patients from the Leicester teaching hospitals with acute hemispheric stroke within the previous 24 hours (139 men; median age, 75 years [range, 42 to 98 years]), we prospectively studied BP changes between admission, 24 hours, 1 week, and 4 to 6 weeks. Changes were assessed in relation to the main stroke risk factors, stroke type and severity, and antihypertensive drug treatment. All subjects were followed up for 1 week, with 117 subjects followed up for 4 to 6 weeks. Changes were assessed by repeated-measures ANOVA, and Student's t tests were used to compare group pairs.

RESULTS

Systolic and diastolic BP fell by 12 mm Hg (95% confidence interval [CI], 8 to 15 mm Hg) and 7 mm Hg (95% CI, 5 to 9 mm Hg), respectively, in the first 24 hours and 22 mm Hg (95% CI, 18 to 25 mm Hg) and 12 mm Hg (95% CI, 10 to 14 mm Hg), respectively, during the first week (all changes significant at P < .01) but no further thereafter. In those patients receiving no antihypertensive medication before or after stroke, the pattern of change was similar to that of the whole group. Previously diagnosed hypertensive subjects (n = 106) had higher initial BP values than did normotensive subjects, although by 1 week the levels were not significantly different. Patients with cerebral hemorrhage confirmed by computed tomography (n = 20) had higher systolic BP, but not diastolic BP, throughout the first week than those with cerebral infarction (n = 89). The severity of stroke, age, and previous stroke history did not appear to alter the BP pattern. Stroke patients who were moderate to heavy alcohol consumers had lower convalescent systolic BP levels than lighter drinkers or abstainers.

CONCLUSIONS

We have demonstrated a marked fall in systolic and diastolic BP levels during the first 7 days after acute hemispheric stroke, with little change thereafter. Higher initial systolic BP values were found in patients with cerebral hemorrhage compared with those with cerebral infarct. Moderate to heavy alcohol consumption before stroke was associated with a greater systolic BP decline in the first week after the event compared with stroke patients who were light drinkers or abstainers.