A trial of blood pressure reduction in acute stroke

Effect of continuing versus stopping pre-stroke antihypertensive agents within 12 h on outcome after stroke: A subgroup analysis of the efficacy of nitric oxide in stroke (ENOS) trial

BACKGROUND

It is not known whether to continue or temporarily stop existing antihypertensive drugs in patients with acute stroke.

METHODS

We performed a prospective subgroup analysis of patients enrolled into the Efficacy of Nitric Oxide in Stroke (ENOS) trial who were randomised to continue vs stop prior antihypertensive therapy within 12 h of stroke onset. The primary outcome was functional outcome, assessed with the modified Rankin Scale at 90 days by observers blinded to treatment assignment, and analysed with ordinal logistic regression.

FINDINGS

Of 4011 patients recruited into ENOS from 2001 to 2014, 2097 patients were randomised to continue vs stop prior antihypertensive treatment, and 384 (18.3%, continue 185, stop 199) were enrolled within 12 h of ictus: mean (SD) age 71.8 (11.8) years, female 193 (50.3%), ischaemic stroke 342 (89.1%) and total anterior circulation syndrome 114 (29.7%). As compared with stopping, continuing treatment within 12 h of onset lowered blood pressure by 15.5/9.6 mmHg (p<0.001/<0.001) by 7 days, shifted the modified Rankin Scale to a worse outcome by day 90, adjusted common odds ratio (OR) 1.46 (95% CI 1.01-2.11), and was associated with an increased death rate by day 90 (hazard ratio 2.17, 95% CI 1.24-3.79). Other outcomes (disability - Barthel Index, quality of life - EQ-visual analogue scale, cognition - telephone mini-mental state examination, and mood - Zung depression scale) were also worse with continuing treatment.

INTERPRETATION

In this pre-specified subgroup analysis of the large ENOS trial, continuing prior antihypertensive therapy within 12 h of stroke onset in a predominantly ischaemic stroke population was unsafe with worse functional outcome, disability, cognition, mood, quality of life and increased death. Future studies assessing continuing or stopping prior antihypertensives in the context of thrombectomy are awaited.

Efficacy of nitric oxide, with or without continuing antihypertensive treatment, for management of high blood pressure in acute stroke (ENOS): a partial-factorial randomised controlled trial

BACKGROUND

High blood pressure is associated with poor outcome after stroke. Whether blood pressure should be lowered early after stroke, and whether to continue or temporarily withdraw existing antihypertensive drugs, is not known. We assessed outcomes after stroke in patients given drugs to lower their blood pressure.

METHODS

In our multicentre, partial-factorial trial, we randomly assigned patients admitted to hospital with an acute ischaemic or haemorrhagic stroke and raised systolic blood pressure (systolic 140-220 mm Hg) to 7 days of transdermal glyceryl trinitrate (5 mg per day), started within 48 h of stroke onset, or to no glyceryl trinitrate (control group). A subset of patients who were taking antihypertensive drugs before their stroke were also randomly assigned to continue or stop taking these drugs. The primary outcome was function, assessed with the modified Rankin Scale at 90 days by observers masked to treatment assignment. This study is registered, number ISRCTN99414122.

FINDINGS

Between July 20, 2001, and Oct 14, 2013, we enrolled 4011 patients. Mean blood pressure was 167 (SD 19) mm Hg/90 (13) mm Hg at baseline (median 26 h [16-37] after stroke onset), and was significantly reduced on day 1 in 2000 patients allocated to glyceryl trinitrate compared with 2011 controls (difference -7·0 [95% CI -8·5 to -5·6] mm Hg/-3·5 [-4·4 to -2·6] mm Hg; both p<0·0001), and on day 7 in 1053 patients allocated to continue antihypertensive drugs compared with 1044 patients randomised to stop them (difference -9·5 [95% CI -11·8 to -7·2] mm Hg/-5·0 [-6·4 to -3·7] mm Hg; both p<0·0001). Functional outcome at day 90 did not differ in either treatment comparison-the adjusted common odds ratio (OR) for worse outcome with glyceryl trinitrate versus no glyceryl trinitrate was 1·01 (95% CI 0·91-1·13; p=0·83), and with continue versus stop antihypertensive drugs OR was 1·05 (0·90-1·22; p=0·55).

INTERPRETATION

In patients with acute stroke and high blood pressure, transdermal glyceryl trinitrate lowered blood pressure and had acceptable safety but did not improve functional outcome. We show no evidence to support continuing prestroke antihypertensive drugs in patients in the first few days after acute stroke.

FUNDING

UK Medical Research Council.

Interventions for deliberately altering blood pressure in acute stroke

BACKGROUND

It is unclear whether blood pressure should be altered actively during the acute phase of stroke. This is an update of a Cochrane review first published in 1997, and previously updated in 2001 and 2008.

OBJECTIVES

To assess the clinical effectiveness of altering blood pressure in people with acute stroke, and the effect of different vasoactive drugs on blood pressure in acute stroke.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (last searched in February 2014), the Cochrane Database of Systematic reviews (CDSR) and the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2014, Issue 2), MEDLINE (Ovid) (1966 to May 2014), EMBASE (Ovid) (1974 to May 2014), Science Citation Index (ISI, Web of Science, 1981 to May 2014) and the Stroke Trials Registry (searched May 2014).

SELECTION CRITERIA

Randomised controlled trials of interventions that aimed to alter blood pressure compared with control in participants within one week of acute ischaemic or haemorrhagic stroke.

DATA COLLECTION AND ANALYSIS

Two review authors independently applied the inclusion criteria, assessed trial quality and extracted data. The review authors cross-checked data and resolved discrepancies by discussion to reach consensus. We obtained published and unpublished data where available.

MAIN RESULTS

We included 26 trials involving 17,011 participants (8497 participants were assigned active therapy and 8514 participants received placebo/control). Not all trials contributed to each outcome. Most data came from trials that had a wide time window for recruitment; four trials gave treatment within six hours and one trial within eight hours. The trials tested alpha-2 adrenergic agonists (A2AA), angiotensin converting enzyme inhibitors (ACEI), angiotensin receptor antagonists (ARA), calcium channel blockers (CCBs), nitric oxide (NO) donors, thiazide-like diuretics, and target-driven blood pressure lowering. One trial tested phenylephrine.At 24 hours after randomisation oral ACEIs reduced systolic blood pressure (SBP, mean difference (MD) -8 mmHg, 95% confidence interval (CI) -17 to 1) and diastolic blood pressure (DBP, MD -3 mmHg, 95% CI -9 to 2), sublingual ACEIs reduced SBP (MD -12.00 mm Hg, 95% CI -26 to 2) and DBP (MD -2, 95%CI -10 to 6), oral ARA reduced SBP (MD -1 mm Hg, 95% CI -3 to 2) and DBP (MD -1 mm Hg, 95% CI -3 to 1), oral beta blockers reduced SBP (MD -14 mm Hg; 95% CI -27 to -1) and DBP (MD -1 mm Hg, 95% CI -9 to 7), intravenous (iv) beta blockers reduced SBP (MD -5 mm Hg, 95% CI -18 to 8) and DBP (-5 mm Hg, 95% CI -13 to 3), oral CCBs reduced SBP (MD -13 mmHg, 95% CI -43 to 17) and DBP (MD -6 mmHg, 95% CI -14 to 2), iv CCBs reduced SBP (MD -32 mmHg, 95% CI -65 to 1) and DBP (MD -13, 95% CI -31 to 6), NO donors reduced SBP (MD -12 mmHg, 95% CI -19 to -5) and DBP (MD -3, 95% CI -4 to -2) while phenylephrine, non-significantly increased SBP (MD 21 mmHg, 95% CI -13 to 55) and DBP (MD 1 mmHg, 95% CI -15 to 16).Blood pressure lowering did not reduce death or dependency either by drug class (OR 0.98, 95% CI 0.92 to 1.05), stroke type (OR 0.98, 95% CI 0.92 to 1.05) or time to treatment (OR 0.98, 95% CI 0.92 to 1.05). Treatment within six hours of stroke appeared effective in reducing death or dependency (OR 0.86, 95% CI 0.76 to 0.99) but not death (OR 0.70, 95% CI 0.38 to 1.26) at the end of the trial. Although death or dependency did not differ between people who continued pre-stroke antihypertensive treatment versus those who stopped it temporarily (worse outcome with continuing treatment, OR 1.06, 95% CI 0.91 to 1.24), disability scores at the end of the trial were worse in participants randomised to continue treatment (Barthel Index, MD -3.2, 95% CI -5.8, -0.6).

AUTHORS' CONCLUSIONS

There is insufficient evidence that lowering blood pressure during the acute phase of stroke improves functional outcome. It is reasonable to withhold blood pressure-lowering drugs until patients are medically and neurologically stable, and have suitable oral or enteral access, after which drugs can than be reintroduced. In people with acute stroke, CCBs, ACEI, ARA, beta blockers and NO donors each lower blood pressure while phenylephrine probably increases blood pressure. Further trials are needed to identify which people are most likely to benefit from early treatment, in particular whether treatment started very early is beneficial.

Acute stroke hypertension: current and future management

The management of hypertension in acute stroke remains a hotly debated issue. Clinical practice varies widely between physicians, and both European and US guidelines reflect the uncertainty surrounding this question. Although there is a large amount of data that, on the whole, tends to support a connection between poststroke hypertension and hypotension and worse outcome, there have been few randomized controlled trials to clarify whether pharmacologic intervention is safe or beneficial. Data from secondary prevention trials convincingly demonstrate the benefits of controlling hypertension after a stroke but do not guide us as to how early to implement therapy. There is even less information from trials regarding the use of pressor agents in hypotensive stroke patients. This review discusses the dilemmas in the management of acute stroke hypertension and summarizes the available evidence from studies involving a variety of both depressor and pressor agents. The authors detail the ongoing studies that will help to answer some of the outstanding questions and summarizes the existing guidelines regarding indications for acute stroke blood pressure manipulation currently available to physicians.

High Blood Pressure as Risk Factor and Prognostic Predictor in Acute Ischaemic Stroke: When and How to Treat It?

High blood pressure is common in the western world and is a major risk factor for the development of stroke. Lowering blood pressure reduces the risk of first and recurrent stroke. High blood pressure is also common in acute stroke and is independently associated with a poor prognosis, in part due to promoting early recurrence and the development of fatal cerebral oedema in patients with ischaemic stroke and, possibly, re-bleeding in those with haemorrhagic stroke. However, the management of blood pressure remains an enigma--its lowering could improve outcome by reducing recurrence or worsen outcome by reducing regional perfusion in the face of dysfunctional cerebral autoregulation. Conversely, raising blood pressure might improve outcome by raising regional perfusion or worsen it by inducing cerebral oedema and early recurrence. Administration of some vaso-active drugs (beta-receptor antagonists and calcium channel blockers) can worsen outcome and reduce cerebral blood flow. In contrast, other drug classes--angiotensin- converting enzyme inhibitors, angiotensin receptor antagonists and nitrates--appear to lower blood pressure without reducing measures of cerebral perfusion. In the absence of definitive trial data, which is urgently needed, blood pressure should not be routinely lowered unless it is extreme (systolic blood pressure >220 mm Hg) or associated with arterial dissection or cardiac ischaemia or failure, in which case cautious lowering (<15%), perhaps with an angiotensin-converting enzyme inhibitor, angiotensin receptor antagonist or nitrate, is appropriate.

Nitric oxide donors (nitrates), L-arginine, or nitric oxide synthase inhibitors for acute ischaemic stroke

BACKGROUND

Nitric oxide has several effects that may be beneficial in ischaemic stroke and useful in the management of hypertension in acute stroke. Some forms of nitric oxide synthase inhibition may also be beneficial. However, high concentrations of nitric oxide are likely to be toxic to brain tissue.

OBJECTIVES

The objective of this review was to assess the effects of nitric oxide donors, L-arginine, or nitric oxide synthase-inhibitors in people with acute ischaemic stroke.

SEARCH STRATEGY

We searched the Cochrane Stroke Group trials register (July 1997), Medline (for trials from 1965), Embase (from 1980) and ISI (from 1981). We contacted drug companies and researchers in the field.

SELECTION CRITERIA

Randomised and quasi-randomised trials comparing nitric oxide donors, L-arginine, or nitric oxide synthase-inhibitors in patients within one week of onset of confirmed ischaemic stroke.

DATA COLLECTION AND ANALYSIS

Two reviewers independently applied the inclusion criteria.

MAIN RESULTS

No completed trials were found. One small placebo-controlled trial of glyceryl trinitrate patches is underway.

REVIEWER'S CONCLUSIONS

There is currently no evidence from randomised trials on the effects of nitric oxide donors, L-arginine, or nitric oxide synthase-inhibitors in patients with acute ischaemic stroke.