Controversies in Blood Pressure Management During Stroke

Stroke is the second leading cause of death in the world, and hypertension is the leading risk factor. More than 75% of patients with acute stroke will have a systolic blood pressure above 140 mm Hg at the time of admission, and in most patients, blood pressure will return to pre-stroke levels spontaneously within one week. Although the American Stroke Association and the European Stroke Initiative have guidelines for treatment of hypertension after acute stroke, more research is needed when it comes to developing guidelines for treating hypertension during the acute phase of stroke.^1,2

A reduction in recurrent stroke has been associated with lowering systolic pressure by 10/5 mm Hg.³ After both hemorrhagic and ischemic stroke, the current guidelines recommend that the target goal be less than 140/90, or less than 130/80 if there are such comorbidities as renal disease or diabetes. Blood pressure should not be lowered below 120/80. However, recommendations for blood pressure control during the acute phase of stroke are more controversial.²

Managing Blood Pressure in the Acute Phase of Stroke

A 2014 review of blood pressure management during acute stroke, concluded that more research is needed to identify which patients are likely to benefit from lowering blood pressure, when the treatment should be given, and what types of stroke are likely to respond favorably. The review, published in Cochrane Database of Systematic Reviews, included 26 trials involving more than 17,000 patients.²

“There is no established answer to how long the acute stroke period lasts. In our research trials we have defined it as less than 48 hours,” said Philip Bath, MD, head of the division of clinical neuroscience and associate professor of stroke medicine at the University of Nottingham in the United Kingdom, who was an author of the review.

The rise in blood pressure that occurs during the phase of acute stroke may be an important protective reaction. It may also be a symptom of stress. Whether to treat elevated pressure during this phase is one of the major unresolved issues in stroke management.⁴

Hemorrhagic vs. Ischemic

Type of stroke is the most important consideration for blood pressure management in the acute phase of stroke. “In an acute ischemic stroke, you may need to lower blood pressure to under 185/110 within 30 minutes in order to safely give recombinant tissue-type plasminogen activator,” said Favate.

“Other than for giving intravenous thrombolysis, I tend to not lower blood pressure unless the systolic pressure is greater than 220,” said Bath.² Thus far, trials on blood pressure management in acute ischemic stroke have been characterized by discrepancies in design, antihypertensive agents used, and blood pressure reductions, but most resulted in no significant differences in outcomes.⁴

The same insignificant outcomes have plagued trials on hemorrhagic stroke as well. A 2014 study published in The Lancet Neurology looked at nearly 3,000 patients enrolled in the INTERACT2 trial. Patients were randomly assigned to intensive treatment to lower systolic pressure to under 140 within one hour or a less intensive lowering to 180 within six hours. The trial could not conclude that more intensive treatment improved outcomes. However, it did find that maintaining smoother control with less variability of systolic pressure improved outcomes.

“The INTERACT2 trial suggests that lowering blood pressure below 140 may improve outcomes, but results were not statistically significant. Other studies have found no benefit. At this point, guidelines say lower systolic blood pressure below 180. We need another big trial,” said Bath.

“Based on INTERACT2, lowering systolic blood pressure to 130 in the acute phase of hemorrhagic stroke makes sense. It should be done gradually to avoid hypoxia,” said Favate.

What About Medications During Acute Stroke?

About 50% of patients diagnosed with stroke are already on blood pressure medications, but the question remains whether or not to continue to administer those medications during and after stroke.² The results of the ENOS trial, which were recently presented at the European Stroke Conference, found no evidence to support continuing pre-stroke medications during the acute phase of stroke.^6,7 “These medications should be delayed until the patient is stable,” said Bath, who was an investigator for the trial.

The ENOS trial also found that lowering blood pressure with transdermal glyceryl trinitrate (GTN) was safe but did not improve functional outcome.^8,9 “There really are no medications that have been shown to be best for lowering blood pressure after stroke. People have tried lots of different agents. Beta-blockers and angiotensin receptor antagonists should be avoided,” said Bath.

“Treatment of blood pressure during the acute phase of stroke is an ongoing evolution,” said Favate. One trial that may further the evolution for ischemic stroke care is ENCHANTED. The global, ongoing trial, which started in 2012, hopes to determine whether lowering blood pressure quickly during acute stroke and maintaining blood pressure at levels that are lower than currently recommended improves survival and reduces disability.¹⁰

Chris Iliades, MD, is a full-time freelance writer based in Cape Cod, Massachusetts.

This article was medically reviewed by Pat F. Bass III, MD, MS, MPH.

References

Feldstein CA. Early treatment of hypertension in acute ischemic and intracerebral hemorrhagic stroke: progress achieved, challenges, and perspectives. J Am Soc Hypertens. 2014;8(3):192-202.
Bath PM, Krishnan K. Interventions for deliberately altering blood pressure in acute stroke. Cochrane Database Syst Rev. 2014;10:CD000039.
Feldstein CA. Lowering blood pressure to prevent stroke recurrence: a systematic review of long-term randomized trials. J Am Soc Hypertens. 2014;8(7):503-13.
Hubert GJ, Müller-barna P, Haberl RL. Unsolved issues in the management of high blood pressure in acute ischemic stroke. Int J Hypertens. 2013;2013:349782. Available here: http://www.hindawi.com/journals/ijhy/2013/349782/
Manning L et al. Blood pressure variability and outcome after acute intracerebral haemorrhage: a post-hoc analysis of INTERACT2, a randomised controlled trial. 2014; doi:10.1016/S1474-4422(14)70018-3
ENOS: No Rush to Continue Oral BP Meds in Acute Stroke, Medscape, http://www.medscape.com/viewarticle/824902.
ENOS investigators. 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. 2014; doi:10.1016/S0140-6736(14)61121-1.
What Is Enchanted, Enchanted.org, http://www.enchanted.org.au/