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

Background:Nitric oxide (NO) has multiple effects that may be beneficial in acute stroke, including lowering blood pressure, and promoting reperfusion and cytoprotection. Some forms of nitric oxide synthase inhibition (NOS-I) may also be beneficial. However, high concentrations of NO are likely to be toxic to brain tissue. This is an update of a Cochrane review first published in 1998, and last updated in 2002. Objectives:To assess the safety and efficacy of NO donors, L-arginine, and NOS-I in people with acute stroke. Search methods: We searched the Cochrane Stroke Group Trials Register (last searched 6 February 2017), MEDLINE (1966 to June 2016), Embase (1980 to June 2016), ISI Science Citation Indexes (1981 to June 2016), Stroke Trials Registry (searched June 2016), International Standard Randomised Controlled Trial Number (ISRCTN) (searched June 2016), Clinical Trials registry (searched June 2016), and International Clinical Trials Registry Platform (ICTRP) (searched June 2016). Previously, we had contacted drug companies and researchers in the field. Selection criteria: Randomised controlled trials comparing nitric oxide donors, L-arginine, or NOS-I versus placebo or open control in people within one week of onset of confirmed stroke. Data collection and analysis: Two review authors independently applied the inclusion criteria, assessed trial quality and risk of bias, and extracted data. The review authors cross-checked data and resolved issues through discussion. We obtained published and unpublished data, as available. Data were reported as mean difference (MD) or odds ratio (OR) with 95% confidence intervals (CI). Main results: We included five completed trials, involving 4197 participants; all tested transdermal glyceryl trinitrate (GTN), an NO donor. The assessed risk of bias was low across the included studies; one study was double-blind, one open-label and three were single-blind. All included studies had blinded outcome assessment. Overall, GTN did not improve the primary outcome of death or dependency at the end of trial (modified Rankin Scale (mRS) > 2, OR 0.97, 95% CI 0.86 to 1.10, 4195 participants, high-quality evidence). GTN did not improve secondary outcomes, including death (OR 0.78, 95% CI 0.40 to 1.50) and quality of life (MD -0.01, 95% CI -0.17 to 0.15) at the end of trial overall (high-quality evidence). Systolic/diastolic blood pressure (BP) was lower in people treated with GTN (MD -7.2 mmHg (95% CI -8.6 to -5.9) and MD -3.3 (95% CI -4.2 to -2.5) respectively) and heart rate was higher (MD 2.0 beats per minute (95% CI 1.1 to 2.9)). Headache was more common in those randomised to GTN (OR 2.37, 95% CI 1.55 to 3.62). We did not find any trials assessing other nitrates, L-arginine, or NOS-I. Authors' conclusions: There is currently insufficient evidence to recommend the use of NO donors, L-arginine or NOS-I in acute stroke, and only one drug (GTN) has been assessed. In people with acute stroke, GTN reduces blood pressure, increases heart rate and headache, but does not alter clinical outcome (all based on high-quality evidence)

Route of feeding as a proxy for dysphagia after stroke and the effect of transdermal glyceryl trinitrate: data from the efficacy of nitric oxide in stroke randomised controlled trial

Post-stroke dysphagia is common, associated with poor outcome and often requires non-oral feeding/fluids. The relationship between route of feeding and outcome, as well as treatment with glyceryl trinitrate (GTN), was studied prospectively. The Efficacy of Nitric Oxide in Stroke (ENOS) trial assessed transdermal GTN (5 mg versus none for 7 days) in 4011 patients with acute stroke and high blood pressure. Feeding route (oral = normal or soft diet; nonoral = nasogastric tube, percutaneous endoscopic gastrostomy tube, parenteral fluids, no fluids) was assessed at baseline and day 7. The primary outcome was the modified Rankin Scale (mRS) measured at day 90. At baseline, 1331 (33.2%) patients had non-oral feeding, were older, had more severe stroke and more were female, than 2680 (66.8%) patients with oral feeding. By day 7, 756 patients had improved from non-oral to oral feeding, and 119 had deteriorated. Non-oral feeding at baseline was associated with more impairment at day 7 (Scandinavian Stroke Scale 29.0 versus 43.7; 2p < 0.001), and worse mRS (4.0 versus 2.7; 2p < 0.001) and death (23.6 versus 6.8%; 2p = 0.014) at day 90. Although GTN did not modify route of feeding overall, randomisation ≤6 hours of stroke was associated with a move to more oral feeding at day 7 (odds ratio = 0.61, 95% confidence intervals 0.38, 0.98; 2p = 0.040). As a proxy for dysphagia, non-oral feeding is present in 33% of patients with acute stroke and associated with more impairment, dependency and death. GTN moved feeding route towards oral intake if given very early after stroke

Protocol for a prospective collaborative systematic review and meta-analysis of individual patient data from randomised controlled trials of vasoactive drugs in acute stroke: the Blood pressure in Acute Stroke Collaboration, stage-3 (BASC-3)

Rationale Despite several large clinical trials assessing blood pressure lowering in acute stroke, equipoise remains, particularly for ischaemic stroke. The ‘Blood pressure in Acute Stroke Collaboration’ (BASC) commenced in the mid 1990s focusing on systematic reviews and meta-analysis of blood pressure lowering in acute stroke. From the start, BASC planned to assess safety and efficacy of blood pressure lowering in acute stroke using individual patient data. Aims To determine the optimal management of blood pressure in patients with acute stroke, encompassing both intracerebral haemorrhage and ischaemic stroke. Secondary aims are to assess which clinical and therapeutic factors may alter the optimal management of high blood pressure in patients with acute stroke and to assess the effect of vasoactive treatments on haemodynamic variables. Methods and design Individual patient data from randomised controlled trials of blood pressure management in participants with ischaemic stroke and/or intracerebral haemorrhage enrolled during the ultra-acute (pre-hospital), hyper-acute (<6 hours), acute (<48 hours) and sub-acute (<168 hours) phases of stroke. Study outcomes The primary effect variable will be functional outcome defined by the ordinal distribution of the modified Rankin Scale; analyses will also be carried out in prespecified subgroups to assess the modifying effects of stroke-related and pre-stroke patient characteristics. Key secondary variables will include clinical, haemodynamic and neuroradiological variables; safety variables will comprise death and serious adverse events. Discussion Study questions will be addressed in stages, according to the protocol, before integrating these into a final overreaching analysis. We invite eligible trials to join the collaboration

Impact of hydration status on haemodynamics, effects of acute blood pressure lowering treatment, and prognosis after stroke

BackgroundHigh blood pressure (BP) is common in acute stroke and associated with poor outcome, but the Efficacy of Nitric Oxide in Stroke (ENOS) trial showed no beneficial effect of antihypertensive treatment in this situation. Antihypertensive agents have accentuated effects in dehydrated patients. We assessed the impact of dehydration on haemodynamics, effects of antihypertensive treatment and prognosis in the ENOS trial.MethodsENOS randomised 4011 patients with acute stroke and raised systolic BP to glyceryl trinitrate (GTN) patch or no GTN, and to continue or to stop existing antihypertensive treatment within 48 hours of onset. The primary outcome was functional outcome (modified Rankin Scale, mRS) at day 90. Blood markers of dehydration at baseline were collected at two sites (n=310) and their relation to haemodynamics and outcome was assessed.ResultsThere were no significant associations between dehydration markers and fall in blood pressure from baseline to day 1, and no significant interaction with allocated treatment. Overall, increasing urea was associated with an unfavourable shift in mRS (OR 3.43, 95% CI 1.42 to 8.32, p=0.006) and increased risk of death at day 90 (HR 4.55, 95% CI 1.51 to 13.66, p=0.007).ConclusionsBlood pressure lowering treatment was safe in dehydrated patients, with no precipitous changes in BP, this supporting its use in acute stroke prior to blood markers of dehydration becoming available. Increased baseline urea was associated with poor prognosis after stroke

Relationship between nitrate headache and outcome in patients with acute stroke: results from the efficacy of nitric oxide in stroke (ENOS) trial

IntroductionNitrate-induced headache is common and may signify responsive cerebral vasculature. We assessed the relationship between nitrate-headache and outcome in patients with acute stroke.Materials and MethodsPatients were those randomised to glyceryl trinitrate (GTN) versus no GTN in the Efficacy of Nitric Oxide in Stroke trial. Development of headache by end of treatment (day 7), and functional outcome (modified Rankin Scale, mRS, primary outcome) at day 90, were assessed. Analyses are adjusted for baseline prognostic factors and give odds ratio (OR) and mean difference (MD) with 95% confidence intervals (95% CI).ResultsIn 4011 patients, headache was more common in GTN than control (360, 18.0% vs. 170, 8.5%; 2

Central masked adjudication of stroke diagnosis at trial entry offered no advantage over diagnosis by local clinicians: Secondary analysis and simulation

BackgroundCentral adjudication of stroke type is commonly implemented in large multicentre clinical trials. We investigated the effect of central adjudication of diagnosis of stroke type at trial entry in the Efficacy of Nitric Oxide in Stroke (ENOS) trial.MethodsENOS recruited patients with acute ischaemic or haemorrhagic stroke, and diagnostic adjudication was carried out using cranial scans. For this study, diagnoses made by local site clinicians were compared with those by central, masked adjudicators using kappa statistics. The trial primary analysis and subgroup analysis by stroke type were re-analysed using stroke diagnosis made by local clinicians, and simulations were used to assess the impact of increased non-differential misclassification and subgroup effects.ResultsAgreement on stroke type (Ischaemic, Intracerebral Haemorrhage, Unknown stroke type, No-stroke) was high (κ = 0.92). Adjudication of stroke type had no impact on the primary outcome or subgroup analysis by stroke type. With misclassification increased to 10 times the level observed in ENOS and a simulated subgroup effect present, adjudication would have affected trial conclusions.ConclusionsStroke type at trial entry was diagnosed accurately by local clinicians in ENOS. Adjudication of stroke type by central adjudicators had no measurable effect on trial conclusions. Diagnostic adjudication may be important if diagnosis is complex and a treatment-diagnosis interaction is expected

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

Associations between change in blood pressure and functional outcome, early events and death: results from the Efficacy of Nitric Oxide in Stroke trial.

OBJECTIVES: High blood pressure (BP) is associated with a poor outcome after acute stroke. Early reduction in BP may be associated with fewer early adverse events and deaths, and improved functional outcome. METHODS: Analyses used data from the Efficacy of Nitric Oxide in Stroke trial, a multicentre randomized single-masked and outcome-masked trial of glyceryl trinitrate vs. no glyceryl trinitrate in 4011 patients recruited within 48 h of an ischaemic or haemorrhagic stroke and with raised SBP (140-220 mmHg). Change in SBP from baseline to day 1 was categorized as: more than 15% decrease, 15-5% decrease, 5% decrease to 5% increase (no change - reference) and more than 5% increase. The primary outcome was functional outcome (modified Rankin scale) score at 90 days. RESULTS: Across all patients, both moderate (5-15%) and large (>15%) decreases in SBP were associated with beneficial shifts in the modified Rankin scale relative to patients with no change in BP: adjusted common odds ratio (OR) 0.81 [95% confidence interval (CI) 0.70-0.90] and OR 0.84 (95% CI 0.71-1.00), respectively. A moderate decrease in SBP was also associated with a lower risk of early adverse events, adjusted OR 0.69 (95% CI 0.52-0.90). CONCLUSION: Modest decreases in SBP in acute stroke appear to be associated with fewer early events and better long-term functional outcome

Performance characteristics of methods for quantifying spontaneous intracerebral haemorrhage: data from the Efficacy of Nitric Oxide in Stroke (ENOS) trial

Background: Poor prognosis after intracerebral haemorrhage (ICH) is related to haemorrhage characteristics. Along with developing therapeutic interventions, we sought to understand the performance of haemorrhage descriptors in large clinical trials.Methods: Clinical and neuroimaging data were obtained for 548 participants with ICH from the Efficacy of Nitric Oxide in Stroke (ENOS) trial. Independent observers performed visual categorisation of the largest diameter, measured volume using ABC/2, modified ABC/2, semiautomated segmentation (SAS), fully automatic measurement methods; shape, density and intraventricular haemorrhage were also assessed. Intraobserver and interobserver reliability were determined for these measures.Results: ICH volume was significantly different among standard ABC/2, modified ABC/2 and SAS: (mean) 12.8 (SD 16.3), 8.9 (9.2), 12.8 (13.1) cm3, respectively (p less than 0.0001). There was excellent agreement for haemorrhage volume (n=193): ABC/2 intraobserver intraclass correlation coefficient (ICC) 0.96–0.97, interobserver ICC 0.88; modified ABC/2 intraobserver ICC 0.95–0.97, interobserver ICC 0.91; SAS intraobserver ICC 0.95–0.99, interobserver ICC 0.93; largest diameter: (visual) interadjudicator ICC 0.82, (visual vs measured) adjudicator vs observer ICC 0.71; shape intraobserver ICC 0.88 interobserver ICC 0.75; density intraobserver ICC 0.86, interobserver ICC 0.73. Graeb score (mean 3.53) and modified Graeb (5.22) scores were highly correlated. Using modified ABC/2, ICH volume was underestimated in regular (by 2.2-2.5 cm3, p less than 0.0001) and irregular-shaped haemorrhages (by 4.8-4.9 cm3, p less than 0.0001). Fully automated measurement of haemorrhage volume was possible in only 5% of cases.Conclusions: Formal measurement of haemorrhage characteristics and visual estimates are reproducible. The standard ABC/2 method is superior to the modified ABC/2 method for quantifying ICH volume

Effect of glyceryl trinitrate on haemodynamics in acute stroke: data from the Efficacy of Nitric Oxide in Stroke trial

Background and Purpose: Increased blood pressure (BP), heart rate and their derivatives (variability, pulse pressure, rate-pressure product [RPP]) are associated with poor clinical outcome in acute stroke. We assessed the effects of glyceryl trinitrate (GTN) on haemodynamic parameters, and these on outcome in participants in the Efficacy of Nitric Oxide in Stroke trial.Methods: 4011 patients with acute stroke and raised BP were randomised within 48 hours of onset to transdermal GTN or no GTN for 7 days. Peripheral haemodynamics were measured at baseline (3 measures) and daily (2 measures) during treatment. Between-visit BP variability over days 1 to 7 (as standard deviation) was assessed in quintiles. Functional outcome was assessed as modified Rankin Scale (mRS) and cognition as telephone mini-mental state examination (t-MMSE) at day 90. Analyses were adjusted for baseline prognostic variables. Data are mean difference (MD) or odds ratios (OR) with 95% confidence intervals (CI).Results: Increased baseline BP (diastolic, variability), heart rate and RPP were each associated with unfavourable functional outcome at day 90. Increased between-visit systolic BP variability was associated with an unfavourable shift in mRS (highest quintile adjusted OR 1.65, 95% CI 1.37 to 1.99), worse cognitive scores (t-MMSE: highest quintile adjusted MD -2.03, 95% CI -2.84 to -1.22) and increased odds of death at day 90 (highest quintile adjusted OR 1.57, 95% CI 1.12 to 2.19). GTN lowered BP and RPP, and increased heart rate at day 1; and reduced between-visit systolic BP variability.Conclusions: Increased between-visit BP variability was associated with poor functional and cognitive outcomes and increased death 90 days after acute stroke. In addition to lowering BP and RPP, GTN reduced between-visit systolic BP variability. Agents that lower BP variability in acute stroke require further study