Blood pressure lowering in acute phase of stroke: latest evidence and clinical implications

Abstract

Persistent controversy exists as to whether there are worthwhile beneficial effects of early, rapid lowering of elevated blood pressure (BP) in acute stroke. Elevated BP or 'hypertension' (i.e. systolic >140 mmHg) is common in stroke, especially in patients with pre-existing hypertension and large strokes, due to variable 'autonomic stress' and raised intracranial pressure. While positive associations between BP levels and poor outcomes are evident across a range of studies, very low BP levels and large reductions in BP have also been shown to predict death and dependence, more so for ischaemic stroke (IS) than intracerebral haemorrhage (ICH). Accumulating evidence indicates that early BP lowering can reduce haematoma expansion in ICH, but there is uncertainty over whether this translates into improved clinical outcomes, particularly since such an effect was not evident from haemostatic therapy in clinical trials. Guidelines generally recommend control of high systolic BP (>180 mmHg), but recent evidence indicates that even more modest elevation (>140 mmHg) increases risks of cerebral oedema and haemorrhagic transformation following thrombolysis in IS. Thus, any potential benefits of rapid BP lowering in acute stroke, particularly in IS, must be balanced against the potential risks of worsening cerebral ischaemia from altered autoregulation/perfusion. This paper explores current knowledge regarding the management of hypertension in acute stroke and introduces ongoing clinical trials aimed at resolving such a critical issue in the care of patients with acute stroke.

Keywords: acute stroke; blood pressure; clinical trials; guidelines.

Figure 1.

Proportion of patients who died within 14 days (solid lines) or were dead or dependent at 6 months (dashed lines) by baseline systolic blood pressure. 95% confidence intervals are represented by T bars.

Figure 2.

Adjusted odds ratio (midpoints) of symptomatic intracerebral haemorrhage (ICH) by categories of average postrecombinant tissue plasminogen activator systolic blood pressure (BP) within 24 hours, derived from multivariable analysis. ICH was defined was defined by ≥4 points deterioration in National Institutes of Health Stroke Scale score over 24 hours.

Figure 3.

Adjusted odds ratios (midpoints) for key outcomes (death and dependency) by categories of average postrecombinant tissue plasminogen activator systolic blood pressure (BP) within 24 hours, derived from multivariable analysis. Mortality and independence, defined by modified Rankin Scale scores of ‘6’ and ‘0 to 2’, respectively, at 3 months.