What is the recommended approach for blood pressure management in acute ischemic stroke patients based on the CATIS (China Antihypertensive Trial in Acute Ischemic Stroke) trial?

Blood Pressure Management in Acute Ischemic Stroke: CATIS Trial Findings

Primary Finding and Clinical Recommendation

The CATIS trial demonstrated that immediate blood pressure reduction in acute ischemic stroke patients (within 48 hours of onset) provided no benefit over delayed treatment, showing identical rates of death and major disability at both 14 days (33.5% vs 33.5%) and 3 months (24.7% vs 24.9%). 1

This neutral finding supports the current guideline approach of permissive hypertension in non-thrombolyzed acute ischemic stroke patients.

CATIS Trial Design and Results

Study Protocol

• Population: 4,071 patients with non-thrombolyzed ischemic stroke within 48 hours of onset and elevated systolic blood pressure 1
• Intervention group: Immediate BP lowering by 10-25% within 24 hours, achieving <140/90 mmHg within 7 days 1
• Control group: Discontinuation of all antihypertensive medications during hospitalization 1

Blood Pressure Achieved

• 24-hour BP reduction: Treatment group achieved 144.7 mmHg (12.7% reduction) vs control 152.9 mmHg (7.2% reduction), absolute difference of 9.1 mmHg 1
• Day 7 BP: 137.3 mmHg (treatment) vs 146.5 mmHg (control), difference of 9.3 mmHg 1

Primary Outcome

• Death or major disability at 14 days: No difference between groups (OR 1.00,95% CI 0.88-1.14, P=0.98) 1
• 3-month outcome: Similarly neutral (OR 0.99,95% CI 0.86-1.15, P=0.93) 1

Critical Subgroup Finding: Single Subcortical Infarction with Parent Artery Disease

A crucial exception emerged from CATIS-2 subgroup analysis: patients with single subcortical infarction (SSI) and coexisting parent artery disease (PAD) stenosis had significantly worse outcomes with early BP lowering (23.4% vs 7.7% disability/death, OR 3.67, P=0.03). 2

This represents a high-risk subgroup where early aggressive BP reduction may extend infarction by compromising collateral perfusion to watershed territories 2.

Current Guideline-Based Management Algorithm

For Patients NOT Receiving Reperfusion Therapy

Do not treat blood pressure unless it exceeds 220/120 mmHg during the first 48-72 hours 3, 4, 5

• Cerebral autoregulation is impaired in the ischemic penumbra, making perfusion pressure-dependent 4, 5
• If BP exceeds 220/120 mmHg, reduce mean arterial pressure by only 15% over 24 hours 3, 4
• After 3 days (≥72 hours), initiate or restart antihypertensives if BP ≥140/90 mmHg in neurologically stable patients 3, 4, 5

For Patients Receiving IV Thrombolysis

Blood pressure MUST be <185/110 mmHg before initiating rtPA and maintained <180/105 mmHg for at least 24 hours afterward 3, 4

• Higher BP during thrombolysis significantly increases hemorrhagic transformation risk 4
• Monitor BP every 15 minutes for 2 hours, every 30 minutes for 6 hours, then hourly for 16 hours 3

For Patients Receiving Mechanical Thrombectomy

Maintain BP <180/105 mmHg before and for 24 hours after the procedure 3, 4

Preferred Pharmacological Agents

First-Line Agents

• Labetalol: 10-20 mg IV over 1-2 minutes, may repeat; or continuous infusion 2-8 mg/min 3, 4, 5
  • Preferred due to ease of titration and minimal cerebral vasodilatory effects 5
• Nicardipine: 5 mg/h IV, titrate by 2.5 mg/h every 5-15 minutes, maximum 15 mg/h 3, 4
  • Effective alternative, especially with bradycardia or heart failure 5

Agents to AVOID

• Sublingual nifedipine: Cannot be titrated, causes precipitous BP drops that may compromise cerebral perfusion 3, 4
• Sodium nitroprusside: Adverse effects on cerebral autoregulation and intracranial pressure; reserve only for refractory hypertension 3

Clinical Implications of CATIS for Practice

What CATIS Confirms

1. Permissive hypertension is safe: No harm from withholding antihypertensives in the acute phase for non-thrombolyzed patients 1
2. No benefit to early aggressive lowering: Despite achieving 9 mmHg lower BP, no improvement in functional outcomes 1
3. White matter disease doesn't change management: Neutral effect of early treatment regardless of WMH severity 6

Critical Pitfalls to Avoid

• Treating BP reflexively <220/120 mmHg: May extend infarct by reducing perfusion to penumbra 4, 5
• Rapid BP reduction: Even lowering to hypertensive range can be detrimental if done too quickly 4
• Ignoring parent artery stenosis: Early BP lowering in SSI with PAD stenosis triples risk of poor outcome 2
• Using affected limb for BP measurement: May underestimate true systemic pressure, leading to inappropriate thrombolysis or missed dangerous hypertension 4, 5

Long-Term Secondary Prevention

After 3 days, initiate or restart antihypertensives targeting <130/80 mmHg for secondary prevention in neurologically stable patients with BP ≥140/90 mmHg 4, 5

• Preferred agents: thiazide diuretics, ACE inhibitors, ARBs, or combination therapy 4
• This timing allows acute phase physiology to stabilize while preventing recurrent stroke 3, 4

Special Circumstances Overriding Permissive Hypertension

Immediate BP control required regardless of stroke guidelines in: 3, 4

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