What are the rationale behind the pre-thrombolysis blood pressure (BP) target of severe hypertension and post-thrombolysis target of mild to moderate hypertension in patients undergoing thrombolysis (intravenous administration of a thrombolytic agent)?

From the Guidelines

The pre-thrombolysis blood pressure (BP) target of 185/110 mmHg and post-thrombolysis target of 180/105 mmHg are established to balance the need for adequate cerebral perfusion while minimizing the risk of hemorrhagic complications in stroke patients, as recommended by the 2024 ESC guidelines for the management of elevated blood pressure and hypertension 1. The rationale behind these targets is to minimize the risk of intracranial hemorrhage and reperfusion injury in patients undergoing thrombolysis, while also ensuring sufficient cerebral perfusion pressure is maintained to the ischemic penumbra. Before administering thrombolytic therapy, blood pressure must be below 185/110 mmHg because higher pressures significantly increase the risk of intracranial hemorrhage when the clot-dissolving medication is given. If BP exceeds these targets, medications like labetalol or nicardipine should be administered to achieve target levels before thrombolysis, as these agents can help lower blood pressure without precipitous falls 1. After thrombolysis, the slightly lower target of 180/105 mmHg for the next 24 hours reflects the ongoing hemorrhage risk while the medication is active in the system. This careful BP management is critical because thrombolytics disrupt clotting mechanisms, making any vessel damage from high pressure more likely to bleed. The narrow target range also ensures sufficient cerebral perfusion pressure is maintained to the ischemic penumbra, as excessively lowering BP could worsen the stroke by reducing blood flow to vulnerable brain tissue. Key points to consider in blood pressure management include:

• Avoiding rapid or excessive lowering of blood pressure, which might exacerbate existing ischemia or induce ischemia, particularly in the setting of intracranial or extracranial arterial occlusion 1
• Choosing pharmacological agents and routes of administration to avoid precipitous falls in blood pressure 1
• Treating extreme blood pressure elevation (e.g., SBP > 220 mm Hg or DBP > 120 mmHg) to reduce the blood pressure by approximately 15%, and not more than 25%, over the first 24 h with further gradual reduction thereafter to targets for long-term secondary stroke prevention 1

From the Research

Rationale for Pre-thrombolysis Blood Pressure Target

• The pre-thrombolysis blood pressure target of severe hypertension is based on the upper limit of the pressure autoregulation zone above which cerebral blood flow is directly dependent on blood pressure 2.
• In patients undergoing thrombolysis, blood pressure should be controlled to a level <185/110 mmHg before infusion to limit the risk of intracerebral hemorrhage (ICH) 2.

Rationale for Post-thrombolysis Blood Pressure Target

• The post-thrombolysis target of mild to moderate hypertension is based on the observation that patients with symptomatic intracerebral hemorrhage (sICH) have significantly higher systolic blood pressure at several time-points after thrombolysis compared with those without sICH 3.
• Maintaining systolic blood pressure levels ≤148 mmHg from admission to the first 24 hours after thrombolysis, then keeping systolic blood pressure levels between 127-138 mmHg, may be beneficial for neurological improvement and reducing the risk of intracerebral hemorrhage 4.
• Expert opinion recommends that intraprocedural blood pressure reduction could be associated with a risk of poor outcomes, and therefore, systolic blood pressure may be reduced only to 120 to 140 mmHg after successful reperfusion therapy 2.

Blood Pressure Management in Acute Ischemic Stroke

• High blood pressure is common after ischemic stroke and associated with a poor functional outcome and increased mortality 5.
• The optimal management of blood pressure in the early phase of acute ischemic stroke is still uncertain, and different subgroups of patients may need to have their blood pressure lowered, left alone, or elevated 5.
• A randomized controlled trial is being conducted to determine the safety and effects of intensive blood pressure lowering on cerebral blood flow and functional outcome in patients treated with intravenous thrombolysis 6.