In a patient 12 hours after a transient episode of lower‑extremity weakness that has resolved, with normal vital signs, normal coagulation profile and platelet count, and imaging showing a small‑to‑moderate ischemic core with a proximal anterior‑circulation large‑vessel occlusion, what is the most appropriate management?

Management of Resolved Stroke Symptoms with Persistent Large Vessel Occlusion at 12 Hours

Mechanical embolectomy (Option B) is the most appropriate management for this patient with a proximal anterior circulation occlusion, small-to-moderate ischemic core, and presentation within 12 hours, despite symptom resolution. The presence of a persistent large vessel occlusion with salvageable tissue represents a high-risk situation for devastating stroke progression, and the resolved symptoms do not eliminate the indication for intervention when imaging demonstrates favorable tissue characteristics.

Key Decision Points

Why Mechanical Thrombectomy is Indicated

• The American Heart Association/American Stroke Association recommends mechanical thrombectomy for patients with acute ischemic stroke presenting within 12 hours of onset, with proximal anterior circulation occlusion and moderate-sized infarct core, provided advanced perfusion imaging confirms salvageable tissue 1

• For patients beyond 6-24 hours from symptom onset, thrombectomy is recommended for patients with significant mismatch between the ischemic core and the area of hypoperfusion or clinical deficits 2. Your patient at 12 hours with a small-to-moderate core and persistent occlusion likely has substantial penumbra at risk

• Mechanical thrombectomy achieves superior functional outcomes when salvageable brain tissue is identified, with 49% versus 13% (DAWN) and 44.6% versus 16.7% (DEFUSE-3) achieving good functional outcome with thrombectomy versus control 2

Why Symptom Resolution Does Not Preclude Treatment

• The presence of a proximal anterior circulation large vessel occlusion with a small-to-moderate ischemic core indicates substantial tissue at risk, regardless of transient symptom improvement 3. Spontaneous clinical fluctuation is common with large vessel occlusions, and the persistent occlusion poses ongoing risk

• LVO ischemic events account for 61.6% of post-stroke dependence or death and 95.6% of post-stroke mortality, despite representing only 38.7% of acutely presenting ischemic strokes 4. The natural history of untreated proximal occlusions is poor

• Every 30-minute delay in recanalization decreases the chance of good functional outcome by 8% to 14% 3, emphasizing the urgency of intervention when favorable imaging is present

Why tPA Alone (Option A) is Insufficient

• Intravenous thrombolysis appears more efficacious for distal than for proximal thrombus, and mechanical thrombectomy may be more efficacious for treatment of proximal large-vessel occlusion than intravenous thrombolysis 3

• At 12 hours from onset, the patient is beyond the standard 4.5-hour window for intravenous tPA monotherapy, making this option inappropriate even if symptoms had not resolved

Why Combined Therapy (Option C) May Not Be Necessary

• While patients with ELVO who meet criteria for on-label or guideline-directed use of IV thrombolysis should receive IV thrombolysis irrespective of whether endovascular treatments are being considered 5, this patient is beyond the standard tPA window at 12 hours

• The decision for bridging therapy would depend on whether the patient meets extended window tPA criteria, but mechanical thrombectomy remains the primary intervention 3

Why Observation (Option D) is Inappropriate

• The presence of a persistent proximal anterior circulation occlusion with salvageable tissue represents a medical emergency requiring intervention, not observation 1

• ASPECTS ≥6 is the minimum threshold recommended in guidelines, and a small-to-moderate core suggests the patient meets favorable imaging criteria 2, 1

Critical Imaging Considerations

Confirming Salvageable Tissue

• The American Heart Association/American Stroke Association guidelines recommend CTP or DW-MRI with perfusion imaging to demonstrate salvageable tissue for patients in the 6-24 hour window 2

• Favorable mismatch criteria include DAWN criteria (clinical-imaging mismatch with specific age/NIHSS/core volume thresholds) or DEFUSE-3 criteria (ischemic core <70 mL, mismatch ratio ≥1.8, and mismatch volume ≥15 mL) 1

• ASPECTS score of ≥6 on baseline imaging is recommended 1

Contraindications to Rule Out

• Do not proceed with thrombectomy if imaging demonstrates ASPECTS of 0, no perfusion mismatch, or large established infarct core >70 mL 1

• The absence of mismatch in perfusion indicates no salvageable tissue, making intervention unlikely to benefit 2

Technical Execution

• The angiographic goal should be TICI 2b/3 reperfusion to maximize functional outcomes 1, 6

• A combined endovascular therapy approach using stent-retrievers and aspiration is the most effective way to achieve fast first-pass complete reperfusion 3

• Target groin puncture within 60 minutes of CT/CTA completion to minimize door-to-groin puncture time 1

Common Pitfalls to Avoid

• Do not be falsely reassured by transient symptom resolution in the presence of a persistent large vessel occlusion with salvageable tissue—the occlusion remains a high-risk substrate for devastating stroke progression 4

• Do not delay treatment for unnecessary testing; only blood glucose measurement must precede treatment 2

• Avoid patient overselection for treatment, as treatment delays worsen outcomes and the natural course of untreated LVO is poor 3