What is the target blood pressure (BP) in patients with ischemic stroke?

Blood Pressure Target in Ischemic Stroke

Blood pressure targets in acute ischemic stroke depend critically on whether the patient receives reperfusion therapy: maintain BP <185/110 mmHg before thrombolysis and <180/105 mmHg for 24 hours after, while for patients NOT receiving reperfusion therapy, avoid treating BP unless it exceeds 220/120 mmHg during the first 48-72 hours. 1, 2

For Patients Receiving IV Thrombolysis (Alteplase)

Pre-treatment requirements:

• Lower BP to <185/110 mmHg before initiating alteplase 1, 2, 3
• This threshold is mandatory and non-negotiable for thrombolytic eligibility 2

Post-treatment maintenance:

• Maintain BP <180/105 mmHg for at least the first 24 hours after drug administration 1, 2, 3
• Monitor BP every 15 minutes for 2 hours, every 30 minutes for 6 hours, then hourly for 16 hours 2
• Higher BP during this period significantly increases risk of symptomatic intracranial hemorrhage 2

Optimal range based on recent evidence:

• The ENCHANTED trial (2022) demonstrated that attaining SBP as low as 110-120 mmHg over 24 hours post-thrombolysis was associated with better functional outcomes and lower intracranial hemorrhage rates 4
• Lower attained SBP and smaller BP variability (not just magnitude of reduction) were the key factors for favorable outcomes 4

For Patients NOT Receiving Reperfusion Therapy

Conservative approach (first 48-72 hours):

• Do NOT treat BP if <220/120 mmHg - this is a Class III (No Benefit) recommendation 1, 2, 3
• Permissive hypertension during this window may enhance collateral flow to ischemic penumbra 2, 5
• Studies show a U-shaped relationship with optimal admission SBP of 121-200 mmHg 1, 2

If BP ≥220/120 mmHg:

• Consider lowering mean arterial pressure by only 15% over 24 hours 1, 2, 3
• This is a Class IIb recommendation (uncertain benefit) 1
• Avoid aggressive reduction as cerebral autoregulation is impaired and perfusion becomes pressure-dependent 2, 3

After the Acute Phase (>48-72 hours)

Initiation of antihypertensive therapy:

• Start or restart medications in neurologically stable patients with BP >140/90 mmHg after 3 days 2, 3, 5
• This is safe and reasonable for long-term BP control (Class IIa recommendation) 1
• Target <130/80 mmHg for secondary stroke prevention 2, 3

Preferred Pharmacologic Agents

First-line agents for acute BP lowering:

• Labetalol: 10-20 mg IV over 1-2 minutes, may repeat; or continuous infusion 2-8 mg/min 2, 3
  • Preferred due to ease of titration and minimal cerebral vasodilatory effects 2
• Nicardipine: 5 mg/h IV, titrate by 2.5 mg/h every 5-15 minutes, maximum 15 mg/h 2, 3
  • Especially useful with bradycardia or heart failure 2

Agents to avoid:

• Sublingual nifedipine: Cannot be titrated, causes precipitous drops that compromise cerebral perfusion 2, 6
• Sodium nitroprusside: Adverse effects on cerebral autoregulation and intracranial pressure 2, 3, 6

Critical Pitfalls to Avoid

Dangerous practices:

• Treating BP <220/120 mmHg reflexively in the first 48-72 hours without reperfusion therapy - this has been proven ineffective for preventing death or dependency 1, 3
• Rapid BP reduction can extend infarct size by reducing perfusion to the penumbra 2
• Using the affected limb for BP measurement may underestimate true systemic pressure, potentially leading to inappropriate thrombolytic administration 2

Special circumstances requiring immediate BP control (override permissive hypertension):

• Hypertensive encephalopathy 2
• Aortic dissection 2
• Acute myocardial infarction 2
• Acute pulmonary edema 2
• Acute renal failure 2

Physiologic Rationale

The conservative approach stems from impaired cerebral autoregulation in the ischemic penumbra, where perfusion becomes directly pressure-dependent 2, 3. The brain cannot compensate for sudden pressure changes, and even lowering BP to levels within the hypertensive range can be detrimental if done too quickly 2. Both extremes of BP are harmful, creating a U-shaped mortality curve 1, 2.