Abstract
SummaryBackgroundIt is often assumed that blood pressure increases acutely after major stroke, resulting in so-called post-stroke hypertension. In view of evidence that the risks and benefits of blood pressure-lowering treatment in acute stroke might differ between patients with major ischaemic stroke and those with primary intracerebral haemorrhage, we compared acute-phase and premorbid blood pressure levels in these two disorders.MethodsIn a population-based study in Oxfordshire, UK, we recruited all patients presenting with stroke between April 1, 2002, and March 31, 2012. We compared all acute-phase post-event blood pressure readings with premorbid readings from 10-year primary care records in all patients with acute major ischaemic stroke (National Institutes of Health Stroke Scale >3) versus those with acute intracerebral haemorrhage.FindingsOf 653 consecutive eligible patients, premorbid and acute-phase blood pressure readings were available for 636 (97%) individuals. Premorbid blood pressure (total readings 13 244) had been measured on a median of 17 separate occasions per patient (IQR 8–31). In patients with ischaemic stroke, the first acute-phase systolic blood pressure was much lower than after intracerebral haemorrhage (158·5 mm Hg [SD 30·1] vs 189·8 mm Hg [38·5], p<0·0001; for patients not on antihypertensive treatment 159·2 mm Hg [27·8] vs 193·4 mm Hg [37·4], p<0·0001), was little higher than premorbid levels (increase of 10·6 mm Hg vs 10-year mean premorbid level), and decreased only slightly during the first 24 h (mean decrease from <90 min to 24 h 13·6 mm Hg). By contrast with findings in ischaemic stroke, the mean first systolic blood pressure after intracerebral haemorrhage was substantially higher than premorbid levels (mean increase of 40·7 mm Hg, p<0·0001) and fell substantially in the first 24 h (mean decrease of 41·1 mm Hg; p=0·0007 for difference from decrease in ischaemic stroke). Mean systolic blood pressure also increased steeply in the days and weeks before intracerebral haemorrhage (regression p<0·0001) but not before ischaemic stroke. Consequently, the first acute-phase blood pressure reading after primary intracerebral haemorrhage was more likely than after ischaemic stroke to be the highest ever recorded (OR 3·4, 95% CI 2·3–5·2, p<0·0001). In patients with intracerebral haemorrhage seen within 90 min, the highest systolic blood pressure within 3 h of onset was 50 mm Hg higher, on average, than the maximum premorbid level whereas that after ischaemic stroke was 5·2 mm Hg lower (p<0·0001).InterpretationOur findings suggest that systolic blood pressure is substantially raised compared with usual premorbid levels after intracerebral haemorrhage, whereas acute-phase systolic blood pressure after major ischaemic stroke is much closer to the accustomed long-term premorbid level, providing a potential explanation for why the risks and benefits of lowering blood pressure acutely after stroke might be expected to differ.FundingWellcome Trust, Wolfson Foundation, UK Medical Research Council, Stroke Association, British Heart Foundation, National Institute for Health Research.
Highlights
To date, acute poststroke blood pressure levels have not been systematically compared with actual premorbid blood pressure levels
We and others have hypothesised that any benefits of treatment to lower blood pressure in acute stroke might be greater in patients in whom a high post-event level is unaccustomed,[29,30] and we have suggested that in some patients post-stroke hypertension might be due to a recent premorbid increase in blood pressure.[31]
To better understand the nature of acute post-stroke hypertension in intracerebral haemorrhage versus ischaemic stroke, we aimed to determine the relation between premorbid and acute post-event blood pressure in these two subtypes of stroke in the Oxford Vascular Study (OXVASC) study
Summary
Blood pressure is increased in about 75% of patients with acute stroke (post-stroke hypertension) and usually decreases spontaneously over the subsequent few days.[1,2,3,4,5,6,7,8,9,10] Blood pressure in patients with acute stroke is higher than in those with other acute illnesses.[2,7,11] a history of premorbid hypertension is more common in patients with stroke than in otherwise healthy people,[2,7] and is associated with high post-stroke blood pressure[1,2,4,5,6,8,9,12] and more variable blood pressure.[13]. Blood pressure is assumed to increase as a consequence of stroke, possibly due to disturbed autoregulation,[14] damage or compression of brain regions that regulate the autonomic nervous system,[15] neuroendocrine factors,[16,17,18] or as a consequence of headache,[19] urine retention,[14] infection,[19] or the psychological stress of admission to hospital.[6,12] to date, acute poststroke blood pressure levels have not been systematically compared with actual premorbid blood pressure levels.
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