Lowering blood pressure has no effect on stroke outcomes

Blood pressure may not be the key to improving stroke outcomes after all. In an international study published online Oct. 22 in The Lancet, stroke patients randomized to have blood pressure control within 48 hours of infarct did no better than patients whose high blood pressure remained untreated. They did no worse, either.

Researchers with the Efficacy of Nitric Oxide in Stroke (ENOS) trial compared the use of a nitroglycerin (glyceryl trinitrate) patch to lower blood pressure against no blood pressure treatment in patients with ischemic or hemorrhagic stroke. In a partial-factorial substudy, they also divided patients on blood pressure medications prior to stroke to continue or discontinue use. Patients with high blood pressure following stroke were treated within 48 hours of onset and for the following seven days.

Philip M. W. Bath, MD, of the clinical neuroscience division at the University of Nottingham, England, and colleagues assessed patients for functional and safety outcomes at seven and 90 days post-stroke.

In total, 4,011 patients were enrolled in ENOS between 2001 and 2013 across 173 sites in 23 countries.

While both interventional arms showed significant change in blood pressure, neither improved long-term outcomes. Patients given glyceryl trinitrate had a 7 mm Hg/3.5 mm Hg reduction in blood pressure on the first day vs. those who were not, while those told to continue antihypertensive drugs had a reduction of 9.5 mm Hg/5 mm Hg in blood pressure at day seven as opposed to those who discontinued use.

In patients given glyceryl trinitrate, no increased risk of harm or reduction of functional status was seen. In patients told to continue antihypertensive drugs, however, they did note lower scores when assessing daily living activities and cognition and an increased rate of pneumonia.

“Overall, ENOS provides no evidence for the strategy of immediately continuing prestroke blood pressure-lowering drugs after admission to hospital; indeed, such a policy might have a deleterious effect,” they wrote.

“The main implication for practice is that it seems reasonable to withhold blood pressure-lowering drugs until patients with an acute stroke are medically and neurologically stable, and have suitable oral or enteral access to allow safe drug reintroduction.”