Comparison of small volume infarcts of lacunar and non-lacunar etiologies

Baseline Characteristics of the 4011 Patients Recruited into the ‘Efficacy of Nitric Oxide in Stroke’ (ENOS) Trial

Background

High blood pressure is common in acute stroke and associated with a worse functional outcome. Many patients who present with acute stroke are taking prescribed antihypertensive therapy before their stroke.

Aims

ENOS tested whether lowering blood pressure and continuing pre-stroke antihypertensive therapy are each safe and effective.

Methods

This study is an international multi-centre prospective randomized single-blind blinded-endpoint parallel-group partial-factorial controlled trial of transdermal glyceryl trinitrate (a nitric oxide donor, given for seven-days) vs. no glyceryl trinitrate, and of continuing vs. stopping (temporarily for seven-days) pre-stroke antihypertensive drugs if relevant, in patients with acute ischaemic stroke or intracerebral haemorrhage and high systolic blood pressure (140–220 mmHg).

Results

Recruitment ran from July 2001 to October 2013. Four thousand eleven patients [2097 (52·3%) in the continue/stop arm] were recruited from 173 sites across 23 countries in 5 continents (Asia 14%, Continental Europe 16%, UK 64%). Baseline characteristics include: mean age 70 (standard deviation 12) years; male 57%; mean time from stroke to recruitment 26 ( 13 ) h; mean severity (Scandinavian Stroke Scale) 34 ( 13 ) of 58; mean blood pressure 167 ( 19 )/90 ( 13 ) mmHg; ischaemic stroke 83%; and intracerebral haemorrhage 16%. The main trial results will be presented in May 2014. The results will also be presented in updated Cochrane systematic reviews and included in individual patient data meta-analyses of all relevant randomized controlled trials.

Conclusion

ENOS is a large completed international trial of blood pressure management in acute stroke and includes patients representative of many stroke services worldwide.

Statistical analysis plan for the 'Efficacy of Nitric Oxide in Stroke' (ENOS) trial

High blood pressure is common during the acute phase of stroke and is associated with a poor outcome. However, the management of high blood pressure remains unclear. The 'Efficacy of Nitric Oxide in Stroke' trial tested whether transdermal glyceryl trinitrate, a nitric oxide donor that lowers blood pressure, is safe and effective in improving outcome after acute stroke. Efficacy of Nitric Oxide in Stroke is an international multicenter, prospective, randomized, single-blind, blinded endpoint trial, with funding from the U.K. Medical Research Council. Patients with acute ischemic stroke or intracerebral hemorrhage and systolic blood pressure 140-220 mmHg were randomized to glyceryl trinitrate or no glyceryl trinitrate and, where relevant, to continue or stop prestroke antihypertensive therapy. The primary outcome is shift in modified Rankin Scale at three-months. Patients or relatives gave written informed (proxy) consent, and all sites had research ethics approval. Analyses will be done by intention to treat. This paper and attachment describe the trial's statistical analysis plan, developed prior to unblinding of date. The statistical analysis plan contains design and methods for analyses, and unpopulated tables and figures for the two primary publications and some secondary publications. The database will be locked in late February 2014 in preparation for presentation of the results in May 2014. The data from the trial will improve the precision of the estimates of the overall treatment effects (efficacy and safety) of results from completed trials of blood pressure management in acute stroke, and provide the first large-scale randomized evidence on transdermal glyceryl trinitrate, and of continuing (vs. stopping) prestroke antihypertensive medications, in acute stroke.