What level of hypertension causes ischemic stroke?

From the Guidelines

High blood pressure significantly increases the risk of ischemic stroke, with systolic blood pressure above 140 mmHg and diastolic above 90 mmHg considered hypertensive and potentially dangerous. However, there is no single specific blood pressure level that definitively causes an ischemic stroke. Rather, stroke risk increases progressively as blood pressure rises, especially when systolic pressure exceeds 160 mmHg or diastolic exceeds 100 mmHg. Severely elevated blood pressure (hypertensive crisis) with readings above 180/120 mmHg creates an immediate danger. The relationship between blood pressure and stroke is continuous because hypertension damages blood vessels over time, promoting atherosclerosis, reducing vessel elasticity, and creating conditions where blood clots can form and travel to the brain. For stroke prevention, maintaining blood pressure below 130/80 mmHg is generally recommended, though target goals may vary based on individual health factors. Blood pressure management through medication (such as ACE inhibitors, ARBs, calcium channel blockers, or diuretics), regular exercise, sodium restriction, weight management, and stress reduction is essential for reducing stroke risk, as supported by the 2020 International Society of Hypertension Global Hypertension Practice Guidelines 1. Some key points to consider include:

• Hypertension is the most important risk factor for ischemic or hemorrhagic stroke 1
• Stroke can be largely prevented by BP control 1
• BP should be lowered if ≥140/90 mm Hg and treated to a target <130/80 mm Hg (<140/80 in elderly patients) 1
• RAS blockers, CCBs, and diuretics are first-line drugs 1
• Lipid-lowering treatment is mandatory with a LDL-C target <70 mg/dL (1.8 mmol/L) in ischemic stroke 1
• Antiplatelet treatment is routinely recommended for ischemic stroke, but not hemorrhagic stroke, and should be carefully considered in patients with hemorrhagic stroke only in the presence of a strong indication 1. The most recent and highest quality study, the 2020 International Society of Hypertension Global Hypertension Practice Guidelines 1, provides the best evidence for guiding blood pressure management to reduce the risk of ischemic stroke.

From the Research

Blood Pressure Levels and Ischemic Stroke

• The relationship between blood pressure levels and ischemic stroke is complex, with both high and low systolic blood pressures having a detrimental effect on neurologic outcome 2.
• 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 2.
• 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, 2, 4.

Optimal Blood Pressure Targets

• 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, 2.
• In patients in whom administration of recombinant tissue-type plasminogen activator is indicated, BP should be controlled to a level < 185/110 mm Hg before infusion and should be maintained at levels < 180/105 mm Hg to limit the risk of intracerebral hemorrhage (ICH) 3.
• Expert opinion recommends that intraprocedural BP reduction could be associated with a risk of poor outcomes, and therefore, SBP may be reduced only to 120 to 140 mm Hg after successful reperfusion therapy 3.

Management of Hypertension

• The use of predictable and titratable medications that judiciously reduce (approximately 10% to 15%) the initial presenting mean arterial pressure is recommended in situations where antihypertensive treatment is warranted 4.
• Lisinopril, even at small dosages, is well tolerated and an effective hypotensive agent after acute ischemic stroke, gradually reducing BP by 4 h after oral first-dose administration 5.
• The first-line drugs for lowering of blood pressure remain labetalol, nicardipine, and sodium nitroprusside 2.