What are the guidelines for blood pressure (BP) management in acute ischemic stroke?

Blood Pressure Management in Acute Ischemic Stroke

In acute ischemic stroke, blood pressure should generally be left alone unless the patient is receiving reperfusion therapy or BP exceeds 220/120 mmHg, as aggressive BP lowering does not improve outcomes and may worsen cerebral perfusion. 1

BP Management Based on Reperfusion Therapy Status

Patients Receiving IV Thrombolysis

• BP must be lowered to <185/110 mmHg before initiating thrombolysis and maintained at <180/105 mmHg for at least 24 hours after treatment. 1
• This strict control is necessary because elevated BP increases the risk of symptomatic intracranial hemorrhage and reperfusion injury in patients receiving tissue plasminogen activator. 1
• Use IV labetalol as first-line agent, with nicardipine as an alternative, particularly if bradycardia or heart failure is present. 2

Patients Receiving Mechanical Thrombectomy

• BP should be lowered to <180/105 mmHg before thrombectomy and maintained below this threshold for 24 hours. 1
• Evidence for this recommendation is more limited than for thrombolysis, but the same principles regarding reperfusion injury apply. 1

Patients NOT Receiving Reperfusion Therapy

For BP <220/120 mmHg:

• Do not initiate or reinitiate antihypertensive therapy during the first 48-72 hours. 1
• This is a Class III (No Benefit) recommendation from the ACC/AHA guidelines, meaning treatment is ineffective for preventing death or dependency. 1
• Cerebral autoregulation is impaired in acute stroke, making cerebral perfusion directly dependent on systemic BP. 1, 2

For BP ≥220/120 mmHg:

• Consider carefully lowering BP by approximately 10-15% over several hours. 1
• This is a Class IIb recommendation (uncertain benefit), so proceed cautiously. 1
• Avoid rapid or excessive BP reduction, as this can compromise perfusion to the ischemic penumbra. 1, 2

Timing of Antihypertensive Therapy Initiation

First 72 Hours

• Patients with BP <180/105 mmHg do not benefit from introducing or reintroducing BP-lowering medication during the first 72 hours. 1
• The rationale is that impaired cerebral autoregulation makes the ischemic tissue dependent on systemic BP for adequate perfusion. 2, 3

After 3 Days (≥72 Hours)

• For stable patients who remain hypertensive (≥140/90 mmHg) at 3 days or later, initiate or reintroduce BP-lowering medication before hospital discharge. 1, 3
• This is a Class I recommendation for long-term BP control and secondary stroke prevention. 1
• After 3 days, the risk of cerebral hypoperfusion decreases while the benefits of BP control for secondary prevention become more relevant. 3

Neurologically Stable Patients with Pre-existing Hypertension

• Starting or restarting antihypertensive therapy during hospitalization in neurologically stable patients with BP >140/90 mmHg is reasonable to improve long-term BP control. 1
• This is a Class IIa recommendation, meaning it is reasonable and can be useful. 1

Critical Pitfalls to Avoid

Excessive BP Reduction

• Never drop systolic BP by more than 70 mmHg acutely, as this may cause acute renal injury and early neurological deterioration. 1
• Rapid BP reduction, even to levels within the hypertensive range, can be detrimental when cerebral autoregulation is impaired. 1

Treating Moderate Hypertension Too Early

• Do not treat BP <220/120 mmHg in the first 48-72 hours in patients not receiving reperfusion therapy. 1, 2
• Multiple randomized trials and meta-analyses have shown that antihypertensive agents reduce BP during acute stroke but do not improve short- or long-term dependency and mortality rates. 1

Hypotension

• Avoid hypotension at all costs, as it abruptly reduces perfusion to multiple organs including the brain. 1
• Both high and low systolic BP have detrimental effects, with studies showing a U-shaped relationship between admission BP and favorable outcomes. 1, 4

Pharmacological Considerations

Preferred Agents When BP Lowering is Necessary

• Use IV labetalol or nicardipine for controlled BP reduction. 2
• These short-acting agents allow careful titration and avoid precipitous BP drops. 2
• Requires continuous or near-continuous hemodynamic monitoring in a higher dependency clinical area. 1

Agents to Avoid

• Avoid oral short-acting agents like captopril or metoprolol in the acute setting unless in hospital with close monitoring, as patients can be very sensitive to these agents. 1

Long-term Management After Acute Phase

Secondary Prevention

• For patients with ischemic stroke or TIA and an indication for BP lowering, commence BP-lowering therapy before hospital discharge. 1, 2
• Recommended agents include thiazide diuretics, ACE inhibitors, ARBs, or combination therapy with thiazide plus ACE inhibitor. 1, 3
• Target BP for secondary prevention may be <130/80 mmHg after the acute phase has resolved, particularly for lacunar stroke. 3