NursingCenter Blog

Blood Pressure Management in Acute Stroke

Sep 25 2024 by Kerry Corcoran, MSN, RN, CNS, CCRN

Stroke is a sudden interruption in the blood supply to the brain. The two broad subtypes of stroke are ischemic stroke and hemorrhagic stroke. About 80% of strokes are ischemic, and the remaining 20% are hemorrhagic. Ischemic stroke can be either thrombotic (caused by thrombus or plaque formation in the arteries of the brain) or embolic (caused by a blood clot that forms elsewhere in the body, travels through the bloodstream, and blocks one of the arteries in the brain). The two main subtypes of hemorrhagic stroke are intracerebral hemorrhage (ICH) and subarachnoid hemorrhage (SAH). ICH causes bleeding into the brain tissue and is often caused by hypertension. SAH causes bleeding into the subarachnoid space (the space between the arachnoid layer and the pia mater) and is often caused by rupture of a brain aneurysm or an arteriovenous malformation (AVM).

High blood pressure (BP) is one of the primary risk factors for stroke, and the majority of acute stroke patients are hypertensive on presentation, even if they have no known prior history of elevated blood pressure. Management of BP in patients who have had a stroke depends on the stroke subtype, the phase of stroke (when did the stroke symptoms start), acute stroke treatments, and, to a certain degree, the patient’s presenting BP.

Cerebral autoregulation (CA) is the brain’s ability to maintain constant blood flow to the brain in response to changes in BP. In the healthy brain, when BP decreases, blood vessels in the brain dilate to maintain blood flow. Conversely, when BP increases, blood vessels in the brain constrict to increase resistance and maintain constant blood flow. CA can become impaired in acute stroke and result in hypoperfusion, causing further ischemic injury to the brain, or hyper-perfusion, causing new or extended hemorrhage.

The American Heart Association / American Stroke Association (AHA/ASA) guidelines (updated 2019) for early management of patients with acute ischemic stroke (AIS) include:

For patients who are not eligible for intravenous (IV) thrombolytic therapy, allow permissive hypertension (maintain BP less than 220/120 for 24 to 48 hours).
For patients receiving IV thrombolytic therapy:
- Lower BP to 185/110 or below before giving IV thrombolytics
- Maintain BP at 180/105 or below for 24 hours following IV thrombolytic therapy
For patients undergoing mechanical thrombectomy for clot retrieval, the blood pressure guidelines are not as clear. Current guidelines recommend maintaining BP at or below 180/105 following mechanical thrombectomy and avoiding decreases in the systolic BP (SBP) to less than 130 mmHg.

The AHA/ASA guidelines (updated 2022) for the management of patients with spontaneous ICH include:

To reduce hematoma expansion and improve functional outcomes in ICH patients requiring acute BP lowering:
- Initiate treatment within two hours of ICH onset
- Limit BP variability and aim for smooth, sustained BP management
- Reach target BP within one hour
For patients with mild to moderate ICH and a presenting SBP of 150 - 220 mm Hg, lower SBP to 140, maintaining a range of 130 - 150 mm Hg.
In patients with a large or severe ICH or requiring surgical decompression, the safety and efficacy of acute BP lowering are not well established.
There is potential harm in lowering the SBP to below 130 mm Hg in ICH patients.

The AHA/ASA guidelines (updated 2023) for the management of patients with aneurysmal SAH (aSAH) include:

Managing BP in patients with aSAH is a balance between preventing rebleeding and preventing hypoperfusion that may cause secondary ischemic injury.
High BP variability is associated with worse outcomes.
- Gradually reduce BP in those patients that have severe hypertension (SBP greater than 180-200).
- Avoid hypotension (defined as a mean arterial pressure [MAP] less than 65).
Other factors that may affect target BP in patients with aSAH include:
- Presenting BP
- Presence of hydrocephalus or brain edema
- Medical history of renal impairment or hypertension

In addition to close BP monitoring and management in acute stroke patients of all subtypes, frequent neurological examination is essential to monitor for clinical signs and symptoms of ischemia and/or hemorrhage.