The Predictive Role of 24-Hour Compared to Casual Blood Pressure Levels on Outcome following Acute Stroke

Abstract

The predictive value of casual blood pressure (BP) levels following acute stroke on outcome is currently unclear. This may in part reflect the observer bias and variability of casual recordings, which are reduced with 24-hour recordings. We therefore proposed to assess the prognostic significance of 24-hour compared to casual BP in predicting 30-day mortality, dependency and neurological outcome. A total of 136 consecutive patients were assessed within 24 h of ictus by one observer, with casual and 24-hour BP recording, and National Institutes of Health Stroke Scale and Modified Rankin Scale scores. Repeat assessments were made at 7 and 30 days. Admission casual and 24-hour systolic BP (SBP) and diastolic BP levels were significantly higher in patients with poor outcome at 1 month following acute stroke, whether expressed in terms of mortality, dependency or neurological deterioration, on single-variable logistic regression analysis. However, of these variables, only admission 24-hour (not casual) SBP remained a significant outcome predictor in a multiple model containing factors with an established association with poor prognosis. The odds ratio for outcome of death or dependency associated with each 10-mm-Hg increase in 24-hour SBP at admission was 1.88 (95% confidence interval: 1.27-2.78). For an outcome of death or high dependency, the model had a specificity of 75% and sensitivity of 76% when tested by the jackknife technique. Therefore, increasing 24-hour BP levels following acute stroke predict poor outcome. Whether BP should be reduced pharmacologically in the acute stroke period now warrants a suitable prospective intervention trial.

High Blood Pressure in Acute Stroke and Subsequent Outcome

“…There were fewer data for combined death or dependency (1290, 11.8%) and combined death or deterioration (1196, 11.0%). These outcomes were assessed with validated stroke scales in 7 articles (Rankin score, [27][28][29][30][31] Scandinavian Neurological Stroke Scale, 30,32 Canadian Neurological Score, 33 or National Institutes of Health Scale 29 ). The other studies used either nonvalidated scales 9 or qualitative assessments, such as discharge disposition.…”

Effect of Blood Pressure During the Acute Period of Ischemic Stroke on Stroke Outcome

“…In addition to history of hypertension, 4,18 we have identified age, baseline NIHSS score, and increased alcohol consumption as predictors of higher weighted average MAP. Partial anterior circulation infarction and previous myocardial infarction were associated with lower average MAP.…”

“…Although there is evidence that raised BP levels in the acute phase of stroke are associated with a poor prognosis, [2][3][4] other work suggests that BP has little prognostic value 5,6 or even that constantly high BP may indicate good prognosis. 7 There is a possibility of a J-shaped relationship between BP and stroke outcome, with poorer outcome in the groups with extreme BP.…”

Prognostic value of blood pressure in acute stroke

“…Moreover, instead of analysing a single measurement such as the first one post-stroke, using several BP measurements may more reliably reflect any impact of BP level on brain tissue damage or salvage. 3,16,29,30 Therefore, we studied a number of daytime and night-time BP values in separate analyses. Especially high night-time systolic and low night-time diastolic values were identified as independent predictors of stroke outcome.…”

“…[1][2][3] This could be a physiological response to maintain or enhance perfusion of reversibly damaged cerebrum, when normal autoregulatory mechanisms are impaired. 4 However, the general benefit of such a response could be questioned, as high BP in the early phase has been linked to poor outcome, particularly in patients with impaired consciousness.…”