What is the management of hypertensive emergency during an ischemic stroke?

From the Guidelines

The management of hypertensive emergency during an ischemic stroke requires careful blood pressure reduction to balance the risks of hemorrhagic transformation against maintaining adequate cerebral perfusion, with a goal of reducing blood pressure by no more than 15-25% within the first 24 hours for patients not receiving thrombolytic therapy, and maintaining blood pressure below 180/105 mmHg for patients receiving thrombolytic therapy (tPA) 1.

Key Considerations

• For patients not receiving thrombolytic therapy, blood pressure should be gradually lowered if it exceeds 220/120 mmHg, with a goal of reducing by no more than 15-25% within the first 24 hours 1.
• For patients receiving thrombolytic therapy (tPA), blood pressure should be maintained below 180/105 mmHg before, during, and for 24 hours after treatment 1.
• First-line medications include intravenous labetalol (10-20 mg over 1-2 minutes, repeated every 10-20 minutes up to 300 mg), nicardipine (5 mg/hour IV, titrated by 2.5 mg/hour every 5-15 minutes, maximum 15 mg/hour), or clevidipine (1-2 mg/hour IV, doubled every 2-5 minutes until target BP, maximum 21 mg/hour) 1.

Important Warnings

• Avoid rapid or excessive BP reduction as it may worsen cerebral ischemia by decreasing perfusion to the penumbra 1.
• Nitroprusside should be avoided if possible due to risks of increasing intracranial pressure and causing cerebral steal phenomenon 1.

Monitoring and Treatment

• Continuous cardiac monitoring is essential during treatment, and blood pressure should be checked every 15 minutes during the acute phase 1.
• The underlying cause of hypertension should be investigated and addressed once the patient is stabilized 1.

From the FDA Drug Label

In a clinical pharmacologic study in severe hypertensives, an initial 0. 25 mg/kg injection of labetalol HCl, administered to patients in the supine position, decreased blood pressure by an average of 11/7 mmHg. Labetalol produces dose-related falls in blood pressure without reflex tachycardia and without significant reduction in heart rate, presumably through a mixture of its alpha-blocking and beta-blocking effects.

For the management of hypertensive emergency during an ischemic stroke, labetalol can be used to decrease blood pressure. The initial dose is typically 0.25 mg/kg IV, followed by additional doses of 0.5 mg/kg at 15-minute intervals as needed, up to a maximum cumulative dose of 3.25 mg/kg.

• Key considerations:
  • Monitor blood pressure and heart rate closely during treatment.
  • Be cautious when positioning patients to avoid postural hypotension.
  • Consider the patient's overall clinical condition and adjust the dose accordingly.
  • The goal is to gradually reduce blood pressure to a safe range while avoiding excessive decreases that could potentially worsen the ischemic stroke. 2

From the Research

Management of Hypertensive Emergency during Ischemic Stroke

• The management of hypertensive emergency during an ischemic stroke involves careful consideration of the patient's blood pressure and the potential risks and benefits of treatment 3, 4.
• Current guidelines support permissive hypertension in the early course of acute ischemic stroke, with a reasonable goal of lowering blood pressure by 15% during the first 24 hours after onset of stroke 3.
• The level of blood pressure that would mandate treatment is not known, but consensus exists that medications should be withheld unless the systolic blood pressure is greater than 220 mm Hg or the diastolic blood pressure is greater than 120 mm Hg 3.
• For patients undergoing intravenous thrombolysis for acute ischemic stroke, it is recommended that the blood pressure be reduced and maintained below 185 mm Hg systolic for the first 24 hours 3.

Treatment Options

• The first-line drugs for lowering blood pressure in this setting remain labetalol, nicardipine, and sodium nitroprusside 3, 5, 6.
• Other options, such as clevidipine, a third-generation dihydropyridine calcium-channel blocker, have also been shown to be effective in reducing blood pressure and improving outcomes 6.
• A study comparing continuous-infusion labetalol with continuous-infusion nicardipine found that both agents were comparable in terms of safety and efficacy outcomes, including time at goal blood pressure and blood pressure variability 7.

Considerations

• Comorbid conditions, such as myocardial infarction, left ventricular failure, aortic dissection, preeclampsia, or eclampsia, would override the guidelines for permissive hypertension, and a lower blood pressure would be preferred in these conditions 3.
• Children with acute strokes should be managed in the same way as adults, with extrapolated lowering of blood pressures, until further evidence emerges 3.
• The prompt recognition of a hypertensive emergency with the appropriate diagnostic tests and triage will lead to the adequate reduction of blood pressure, ameliorating the incidence of fatal outcomes 5.