Background: At acute stage of ischemic stroke, BP is high and unstable and is stabilized through following few days. Initial high BP is regarded as important prognostic factor, however, there is limited information about change of BP and its effect on outcome.
Method: From prospective stroke registry, a series of patients who admitted at the Seoul National University Bundang Hospital within 24 hours of ischemic stroke onset were consecutively identified between January, 2010 and November, 2014.
Change of BP was estimated by two steps: first step was within 24-h standard deviation of systolic BP (SBPSD) and second one was day-by-day course during first 3 days. The SBPSD at each day was dichotomized into high (SBPSD > 15 mmHg) and low BPV and determined their secular course. Primary outcome was 3-month poor functional outcome (modified Rankin Scale, 3 to 6). Using classification and regression tree method, proportions of poor outcome were classified and analyzed according to BPV status for 3 days.
Results: Of enrolled 2545 study subjects (age, 67.1 ± 13.5 year-old; median baseline NIHSS score, 3), SBPmean showed similar values through acute stage (134.5 ± 16.7 on day 1(D1), 132.9 ± 16.7 on D2 and 134.7 ± 16.7 mmHg on D3). The SBPSD were 14.4 ± 5.0 (D1), 12.5 ± 4.5 (D2) and 12.2 ± 4.6 (D3) mmHg and proportions of high BPV were 37.3%, 23.0% and 26.6%, respectively.
The association between change of BP and primary outcome were demonstrated (Figure). High BPV on D2 was most important factor (normalized importance = 43.7%) and followed by D3 and D1.
Conclusion: In ischemic stroke, high BPV at acute stage is rapidly stabilized. When patients sustain or return to the unstable BP, it would be associated with poor functional outcome.