In a patient with acute ischemic stroke and a blood pressure of approximately 170 mm Hg, should the chronic antihypertensive regimen be continued or held?

Blood Pressure Management in Acute Ischemic Stroke at 170 mmHg

Hold chronic antihypertensive medications for the first 48-72 hours in a patient with acute ischemic stroke and blood pressure of 170 mmHg, unless the patient received or is planned to receive thrombolytic therapy or endovascular treatment. 1

Decision Algorithm Based on Reperfusion Status

If Patient Did NOT Receive Thrombolysis or Thrombectomy:

Do not treat blood pressure at 170 mmHg during the first 48-72 hours. The 2017 ACC/AHA guidelines provide Class III (No Benefit) evidence that initiating or reinitiating antihypertensive treatment in patients with BP less than 220/120 mmHg who did not receive reperfusion therapy is not effective to prevent death or dependency. 1

• Hold all chronic antihypertensive medications temporarily during this acute window, as the brain requires permissive hypertension to maintain cerebral perfusion to the ischemic penumbra where autoregulation is impaired. 2, 3, 4

• Blood pressure at 170 mmHg falls well within the optimal range demonstrated by observational studies showing a U-shaped relationship between admission BP and outcomes, with optimal systolic BP ranging from 121-200 mmHg. 1, 2, 4

• The physiologic rationale is that cerebral autoregulation is grossly abnormal in the ischemic penumbra, and systemic perfusion pressure is needed for blood flow and oxygen delivery to potentially salvageable brain tissue. 1, 2, 4

If Patient Received or Will Receive Thrombolysis:

Blood pressure MUST be lowered to <185/110 mmHg before initiating IV thrombolysis and maintained <180/105 mmHg for at least 24 hours afterward. 1, 3, 4 In this scenario, 170 mmHg systolic is acceptable and does not require treatment before thrombolysis.

• High blood pressure during the initial 24 hours after thrombolysis significantly increases the risk of symptomatic intracranial hemorrhage. 1

• Monitor BP every 15 minutes for 2 hours, every 30 minutes for 6 hours, then hourly for 16 hours after thrombolysis. 3, 4

After the Acute Phase (48-72 Hours)

Restart antihypertensive medications after 48-72 hours if the patient is neurologically stable and BP remains ≥140/90 mmHg. 1, 2, 3 This is a Class IIa recommendation (safe and reasonable) for improving long-term BP control. 1

• The ACC/AHA guidelines provide Class I evidence that adults with previously treated hypertension who experience a stroke should be restarted on antihypertensive treatment after the first few days to reduce risk of recurrent stroke and other vascular events. 1

• Target BP <130/80 mmHg for long-term secondary prevention using thiazide diuretics, ACE inhibitors, ARBs, or combination therapy. 1, 2

Critical Exceptions Requiring Immediate BP Control

Override permissive hypertension guidelines and treat BP immediately if any of these comorbid conditions exist:

• Hypertensive encephalopathy 1, 3, 4
• Acute aortic dissection 3, 4, 5
• Acute myocardial infarction 3, 4, 5
• Acute pulmonary edema 3, 4
• Acute renal failure 3, 4

In these situations, treat BP aggressively per the specific condition's requirements rather than following stroke-specific guidelines. 3, 4

Pharmacological Agents if Treatment Required

If BP treatment becomes necessary (e.g., exceeds 220/120 mmHg or for thrombolysis candidates):

• Labetalol 10-20 mg IV over 1-2 minutes is first-line due to ease of titration and minimal cerebral vasodilatory effects. 3, 4, 5

• Nicardipine 5 mg/h IV, titrated by 2.5 mg/h every 5-15 minutes (maximum 15 mg/h) is an effective alternative, particularly with bradycardia or heart failure. 3, 4, 5

• Avoid sublingual nifedipine as it cannot be titrated and causes precipitous BP drops that may compromise cerebral perfusion. 3, 4, 6

Common Pitfalls to Avoid

• Do not reflexively restart home antihypertensives during the first 48-72 hours unless specific comorbid conditions require BP control. 2, 3, 4 One RCT showed no benefit of continuing prestroke antihypertensive drugs during the first few days after acute stroke. 1

• Avoid rapid BP reduction, which can extend infarct size by reducing perfusion to the penumbra. Studies show that decreases in BP during acute stroke are associated with poor outcomes. 4, 5, 7

• If treatment is required for BP ≥220/120 mmHg, reduce mean arterial pressure by only 15% over 24 hours, not more aggressively. 1, 2, 3, 5

• Recognize that hypotension is potentially more harmful than hypertension in acute stroke and requires urgent evaluation and correction. 1, 3, 4