When to lower blood pressure after an acute ischemic stroke?

From the Guidelines

Blood pressure should be lowered after an acute stroke only if it is extremely elevated, typically above 220/120 mmHg, or if the patient is eligible for thrombolytic therapy, in which case it should be slowly lowered to less than 185/110 mmHg before treatment initiation, as recommended by the most recent guidelines 1. The management of blood pressure after an acute stroke requires careful consideration of timing and the patient's eligibility for specific treatments.

Key Considerations

• In patients not receiving intravenous thrombolysis or mechanical thrombectomy, there is no evidence for actively lowering blood pressure unless it is extremely high (e.g., >220/120 mmHg) 1.
• If blood pressure is extremely high, an initial moderate relative reduction of 10%–15% over a period of hours may be considered 1.
• Patients who are treated with intravenous thrombolysis or mechanical thrombectomy should have more proactive management of severe hypertension, with blood pressure lowered to <185/110 mmHg prior to thrombolysis and then maintained at <180/105 mmHg over the following 24 hours 1.

Medication and Long-term Control

• For stable patients who remain hypertensive (≥140/90 mmHg) ≥3 days after an acute ischemic stroke, initiation or reintroduction of blood pressure-lowering medication is recommended 1.
• The choice of medication may include ACE inhibitors like ramipril or ARBs like losartan, which are often preferred for long-term control.

Rationale

The cautious approach to blood pressure management after an acute stroke is based on the brain's altered autoregulation, where too rapid or aggressive lowering of blood pressure can reduce cerebral perfusion and potentially expand the area of injury 1.

Summary of Recommendations

• Avoid aggressive blood pressure lowering in the first 24-72 hours unless the blood pressure is extremely elevated.
• Lower blood pressure to <185/110 mmHg before thrombolytic therapy in eligible patients.
• Maintain blood pressure below 180/105 mmHg for at least the first 24 hours after initiating drug therapy in patients receiving thrombolytic treatment.
• Consider initiating or reinitiating antihypertensive therapy in neurologically stable patients with blood pressure greater than 140/90 mmHg during hospitalization to improve long-term blood pressure control, unless contraindicated 1.

From the Research

Blood Pressure Management After Acute Stroke

• The management of blood pressure after acute stroke is complex and depends on various factors, including the type of stroke and the patient's individual condition 2, 3, 4, 5, 6.
• Current protocols require strict blood pressure control in patients who are treated with thrombolytic therapy, to reduce the risk of hemorrhagic complications 2.
• In patients presenting with acute intracerebral hemorrhage, blood pressure reduction does not appear to cause significant reduction of cerebral blood flow, but there are no studies to determine if there is a clinical benefit of acute blood pressure reduction in these patients 2.
• Blood pressure reduction is not routinely recommended in patients with acute ischemic stroke, as it may precipitate further cerebral ischemia 2.
• Preliminary studies suggest that there may be a role in the future for blood pressure elevation in the treatment of patients with acute ischemic stroke 2, 3.

Timing of Blood Pressure Reduction

• The optimal timing of blood pressure reduction after acute stroke is not well established, and more research is needed to determine the best approach 3, 4, 5, 6.
• The management of blood pressure after acute ischemic stroke should be tailored to the specific clinical situation, taking into account factors such as the patient's blood pressure levels, the presence of comorbidities, and the risk of hemorrhagic transformation 3, 4, 5.
• Current guidelines recommend various blood pressure goals based on multiple factors, including thresholds specific to certain treatment interventions, but there is limited evidence to support specific blood pressure targets 4, 5.

Clinical Considerations

• Elevated blood pressure is common in patients with acute ischemic stroke, and may occur secondary to the body's own response to preserve cerebral blood flow 4, 5.
• High blood pressure variability has been related to worse outcomes in observational studies, and optimal blood pressure management after acute ischemic stroke remains challenging 5.
• The individualization of blood pressure management protocols based on a complex evaluation of the homeostatic response to focal cerebral ischemia, including but not limited to blood pressure changes, may be a valuable novel goal proposed in acute ischemic stroke, but further trials are warranted 5.