Objectives. To assess the influence of 24 h blood pressure (BP) levels on f
unctional recovery 1 week after stroke and the effect of antihypertensive t
herapy on 24 h BP levels.
Design. Prospective study of patients admitted to hospital over 1 year with
first in a lifetime stroke who underwent 24 h BP and casual measurements.
Setting. Medical wards in a teaching hospital.
Subjects. Of 160 patients, 72 patients admitted to hospital within 24 h of
stroke onset were investigated. Patients with conditions and therapy that i
nterfered with autonomic and sympathetic function were excluded.
Interventions. All subjects underwent 24 h BP and casual recordings on admi
ssion to hospital and at day seven after stroke. The mean 24 h, day and nig
ht systolic BP (SBP) and diastolic BP (DBP) and their differences (nocturna
l BP dip) were recorded. Patients were divided into three groups according
to whether they were taking antihypertensive therapy during the first week:
(i) no therapy, (ii) therapy continued after stroke, and (iii) new therapy
introduced.
Main outcome measures. Functional recovery (Rankin Scale 0-1) and neurologi
cal improvement [Scandinavian Stroke Scale (SSS) greater than or equal to3
points] by 1 week of stroke. Change in circadian 24 h BP over 1 week.
Results. For each 10 mmHg difference between day and night time DBP, the od
ds for making a complete recovery were 4.63 (95% Cl: 1.57-13.7, P = 0.01).
For each 10 mmHg difference between day and night SBP, the odds for making
an improvement in neurological status was 2.24 (951% CI: 1.16-4.32, P = 0.0
16). Significant falls in 24 h DBP (P = 0.01), daytime SBP (P = 0.005) and
mean arterial BP (MABP) (P = 0.04) over I week were demonstrated in patient
s who had just commenced antihypertensive therapy (P = 0.001).
Conclusion. An increase in day to night time BP change is favourable in sho
rt-term outcome after acute stroke. Significant falls in BP are more likely
in patients started on antihypertensive therapy for the first time. Furthe
r research is required to understand the effects of circadian BP rhythm on
stroke outcome.