The two-part ENOS trial (Efficacy of Nitric Oxide in Stroke,), was carried out at The University of Nottingham in collaboration with 23 countries to try to solve two major conundrums faced by doctors when treating people who have suffered a stroke — should blood pressure be lowered using medicated skin patches, and should existing blood pressure medication be stopped or continued after a stroke?

The study involved patients with acute stroke, both ischaemic (blood clot) and haemorrhagic (bleeding). Patients were randomly assigned to receive a glyceryl trinitrate 5mg skin patch (often used in angina patients) or no patch for 7 days. Patients who were already on medication for high blood pressure before their stroke were also randomly assigned to either continue or stop this for 7 days after the stroke.

4,011 patients took part in the study and more than half of these (2201) were recruited by Clinical Research Network: stroke from 98 sites across England. Sally Utton, Trial Coordinator for the study says: ‚ÄúRecruitment for the study rapidly grew once the study was adopted by the Network and it’s the commitment and knowledge of the research staff locally which deserves the credit for this.‚Äù

The Nottingham University Hospitals NHS Trust site, recruited 287 patients into the study and Judith Clarke, Research Nurse on the study explains the successful approach they took: “We had a very comprehensive screening sheet to screen all stroke patients who came into the stroke ward; this made it easy to check the inclusionexclusion criteria for patients. To combat patients coming in throughout the day, we extended our hours from 8am to 8pm including weekends and often research staff would stay late if a patient had consented to the study to finish the work.”

George Blagden, 80, from Clifton, Nottingham suffered a stroke in October last year and upon admittance to hospital agreed to participate in the study, he recalls why he took part in the study: ‚ÄúI was approached to take part in the ENOS study by a researcher who explained what was involved. I agreed to take part because I thought it might help my condition and help others who have a stroke. I think it’s important the NHS offers research studies to patients so that treatments and care can improve.‚Äù

Leading the trial and speaking about the results, Clinical Research Network: stroke Associate Director Professor Philip Bath, said: “We found that in patients with acute stroke and high blood pressure, treatment with glyceryl trinitrate patches had acceptable safety but did not improve functional outcome. But there seemed to be benefit in patients who were treated very early, within 6 hours of the onset of symptoms. We aim to carry out a larger trial, testing very early treatment with the skin patch.”

“Our results also show that there is no evidence to support the policy of continuing pre-stroke blood pressure-lowering medication in the acute phase of stroke. An adverse effect in the group continuing medication was pneumonia in patients who had difficulty swallowing, perhaps due to inhalation of the medication into the lungs. Furthermore, discharge home, disability and cognition were all less favourable in those who were allocated to continue BP treatment immediately.”

Professor Bath added: “Our results suggest that antihypertensive treatment should be continued once a patient who has suffered a stroke is stable and is able to swallow medications safely. But there appears to be no urgency to restart treatment in the first week.”