A 72-year-old woman with a history of atrial fibrillation (not on anticoagulation) and hypertension presents with acute onset of left-sided weakness, left-sided sensory loss, and left homonymous hemianopia. MRI brain shows an acute infarct in the right middle cerebral artery (MCA) territory. Her last known well time was 18 hours ago. Blood pressure is 158/92 mmHg, heart rate 88/min and irregularly irregular. What is the most appropriate acute management?

Explanation

## Clinical Scenario Analysis This patient presents **beyond the 4.5-hour thrombolytic window** (last known well 18 hours ago) with acute ischemic stroke in the MCA territory, likely cardioembolic given her atrial fibrillation. The key question is: what is the **most appropriate acute management**? ## Why Thrombolysis Is Contraindicated (Option C) **Key Point:** IV alteplase is only indicated within **4.5 hours** of symptom onset (or last known well). At 18 hours, the risk of hemorrhagic transformation far exceeds any reperfusion benefit. This option is clearly incorrect. ## Why Mechanical Thrombectomy Is Not the Answer Here (Option B) Mechanical thrombectomy can be considered up to **24 hours** in selected patients with large vessel occlusion (LVO) and favorable perfusion imaging (DAWN/DEFUSE-3 criteria). However, the stem does **not** mention LVO on imaging, no CT/MR angiography findings are provided, and the question asks for the **most appropriate acute management** — not a conditional intervention. Without confirmed LVO, thrombectomy is not the default answer. ## Why Early Anticoagulation Is NOT Recommended Acutely (Option D) **High-Yield:** Current AHA/ASA 2019 and ESO 2021 guidelines do **not** recommend urgent anticoagulation (UFH or LMWH) in the acute phase of ischemic stroke, even in cardioembolic stroke due to AF. The risk of hemorrhagic transformation of a large MCA territory infarct outweighs the benefit of early anticoagulation. The standard recommendation is to **delay anticoagulation** for at least 48 hours to 2 weeks depending on infarct size, and to use **aspirin** in the interim. > *"Urgent anticoagulation with the goal of preventing early recurrent stroke, halting neurological worsening, or improving outcomes after acute ischemic stroke is not recommended."* — AHA/ASA Stroke Guidelines 2019 (Class III, Level of Evidence A) ## Why Aspirin Monotherapy Is Correct (Option A) **Clinical Pearl:** In acute ischemic stroke beyond the thrombolytic window, **aspirin 300 mg** (loading dose) is the cornerstone of acute antiplatelet therapy. Dual antiplatelet therapy (aspirin + clopidogrel) is recommended for **minor stroke or high-risk TIA** (POINT/CHANCE trials), but for a major MCA territory stroke, aspirin monotherapy is the standard acute treatment. The stem does not describe a minor stroke, so aspirin 300 mg alone is the most appropriate answer among the options given. ## Summary Table | Option | Verdict | Reason | |--------|---------|--------| | **A: Aspirin 300 mg** | ✅ Correct | Standard acute management beyond thrombolytic window | | B: Mechanical thrombectomy | ❌ Incorrect | No LVO confirmed; specific imaging criteria not met | | C: IV alteplase | ❌ Incorrect | Outside 4.5-hour window | | D: Aspirin + UFH | ❌ Incorrect | Early anticoagulation not recommended acutely in large MCA infarct (hemorrhage risk) | **High-Yield:** Per AHA/ASA 2019 guidelines, aspirin 325 mg within 24–48 hours of stroke onset is a Class I, Level A recommendation. Anticoagulation for AF-related stroke should be initiated **after** the acute phase (typically 4–14 days depending on infarct size), not immediately. *(Reference: AHA/ASA Guidelines for the Early Management of Patients with Acute Ischemic Stroke, Stroke 2019; Harrison's Principles of Internal Medicine, 21st ed., Chapter on Cerebrovascular Disease)*