In an acute ischemic stroke patient eligible for intravenous alteplase with elevated blood pressure, how should the blood pressure be lowered and maintained before and during thrombolysis?

Management of Blood Pressure During Stroke Thrombolysis

Blood pressure must be lowered to below 185/110 mmHg before initiating alteplase and maintained below 180/105 mmHg for 24 hours after administration using titratable IV antihypertensive agents while avoiding precipitous drops. 1

Pre-Thrombolysis Blood Pressure Targets

Before administering alteplase, blood pressure must be reduced to <185/110 mmHg and stability confirmed. 1 This is a Class I recommendation with Level B evidence from the American Heart Association/American Stroke Association guidelines. 1

Recommended Antihypertensive Agents

For patients with BP >185/110 mmHg who are otherwise eligible for thrombolysis, use one of the following titratable IV agents: 1

• Labetalol 10-20 mg IV over 1-2 minutes, may repeat once 1
• Nicardipine 5 mg/h IV, titrate up by 2.5 mg/h every 5-15 minutes to maximum 15 mg/h 1
• Clevidipine 1-2 mg/h IV, titrate by doubling dose every 2-5 minutes until desired BP reached, maximum 21 mg/h 1

If blood pressure cannot be lowered and maintained below 185/110 mmHg, do not administer alteplase. 1 The Canadian Stroke Best Practice guidelines emphasize that pharmacological agents and routes should be chosen specifically to avoid precipitous falls in blood pressure, as rapid drops can exacerbate ischemia. 1

During and Post-Thrombolysis Blood Pressure Management

After initiating alteplase, maintain blood pressure <180/105 mmHg for the first 24 hours. 1 This slightly lower threshold reduces the risk of hemorrhagic transformation. 1

Monitoring Protocol

Implement the following structured monitoring schedule: 1

• Every 15 minutes for the first 2 hours from start of alteplase 1
• Every 30 minutes for the next 6 hours 1
• Hourly for the remaining 16 hours (up to 24 hours total) 1

Treatment Algorithm for Elevated BP During/After Alteplase

If systolic BP rises to 180-230 mmHg or diastolic BP 105-120 mmHg during or after thrombolysis: 1

• Labetalol 10 mg IV followed by continuous infusion 2-8 mg/min; OR 1
• Nicardipine 5 mg/h IV, titrate up by 2.5 mg/h every 5-15 minutes, maximum 15 mg/h; OR 1
• Clevidipine 1-2 mg/h IV, titrate by doubling dose every 2-5 minutes, maximum 21 mg/h 1

If diastolic BP exceeds 140 mmHg despite the above measures, consider IV sodium nitroprusside. 1 However, nitroprusside should be used cautiously as it can cause precipitous drops and is more difficult to titrate. 1

Critical Pitfalls to Avoid

Never allow rapid or excessive blood pressure lowering—this can exacerbate existing ischemia or induce new ischemia, particularly with intracranial or extracranial arterial occlusion. 1 The Canadian guidelines specifically warn that precipitous drops are more dangerous than gradual reduction. 1

Do not delay alteplase administration to achieve perfect blood pressure control if BP is trending downward and approaching target. 2 Time to treatment is strongly associated with outcomes, and every 15-minute delay reduces the likelihood of favorable outcome. 1

Assess blood pressure stability before initiating alteplase—a single measurement below threshold is insufficient if BP is fluctuating wildly. 1 The physician must assess the stability of BP, not just a single reading. 1

Special Considerations for Mechanical Thrombectomy

For patients undergoing mechanical thrombectomy who have NOT received IV alteplase, maintain BP <185/110 mmHg before the procedure. 1 For those who received alteplase before thrombectomy, maintain the stricter <180/105 mmHg target. 1

The same antihypertensive agents (labetalol, nicardipine, clevidipine) are appropriate for BP management during endovascular procedures. 1

Rationale for Strict BP Control

The evidence supporting these thresholds comes from the understanding that elevated blood pressure during thrombolysis significantly increases the risk of hemorrhagic transformation. 1 The Canadian Stroke Best Practice guidelines note this is Level B evidence for the pre-treatment threshold and Level C evidence for the post-treatment maintenance target. 1

However, the ideal blood pressure target in the hyperacute phase remains unknown, and these thresholds represent consensus based on trial inclusion criteria rather than definitive outcome data. 1 The targets of <185/110 mmHg pre-treatment and <180/105 mmHg post-treatment were derived from the original NINDS trial protocols and have been maintained across subsequent guidelines. 1