In a patient 12 hours after resolved transient lower‑extremity weakness, with normal vital signs, normal coagulation profile and platelet count, and imaging showing a small‑to‑moderate ischemic core and a proximal anterior‑circulation large‑vessel occlusion, what is the most appropriate management: intravenous tissue‑type plasminogen activator (tPA), mechanical embolectomy (endovascular thrombectomy), both, or observation?

Mechanical Embolectomy is the Most Appropriate Management

In this patient presenting 12 hours after symptom onset with resolved weakness but persistent proximal anterior circulation occlusion and small-to-moderate ischemic core, mechanical thrombectomy (embolectomy) is the definitive treatment—option B is correct.

Why Mechanical Thrombectomy Alone

Time Window Excludes IV tPA Monotherapy

• The patient is 12 hours from symptom onset, which exceeds the 4.5-hour FDA-approved window for intravenous tPA, making tPA alone (option A) inappropriate 1, 2.
• At 12 hours, mechanical thrombectomy remains the primary reperfusion strategy regardless of symptom resolution when favorable imaging criteria are met 1.

Persistent Large-Vessel Occlusion Despite Clinical Improvement

• A proximal anterior circulation large-vessel occlusion with a small-to-moderate ischemic core signifies substantial at-risk brain tissue even when clinical symptoms have transiently improved, supporting thrombectomy in this setting 1.
• The natural history of untreated proximal occlusions is associated with high morbidity and mortality; observation (option D) would expose the patient to unacceptable risk 1.
• Transient symptom resolution does not eliminate the need for revascularization when imaging demonstrates persistent occlusion with salvageable tissue 1.

Extended Time Window Eligibility

• Mechanical thrombectomy can be performed up to 24 hours after symptom onset in patients with proximal anterior circulation occlusions and favorable perfusion imaging 3, 2, 4.
• The patient meets criteria for extended-window thrombectomy: proximal anterior circulation occlusion, small-to-moderate core (implying ASPECTS ≥6 or core <70 mL), and presentation within 12 hours 3, 1, 4.
• Both DAWN and DEFUSE-3 trials demonstrated that patients treated up to 24 hours achieved significantly higher rates of functional independence (49% vs. 13% and 44.6% vs. 16.7%) compared to medical management alone 3.

Why Not Combined tPA + Thrombectomy (Option C)

• Beyond the 4.5-hour window, IV tPA is contraindicated, making the combination approach (option C) inappropriate 1, 2.
• For patients presenting beyond the standard tPA window with favorable imaging, mechanical thrombectomy alone is the recommended strategy 1, 2.
• Guidelines recommend not delaying catheter angiography to await the effect of intravenous thrombolysis, as this worsens clinical outcomes 4.

Urgency of Treatment

• Each 30-minute delay in achieving recanalization reduces the probability of good functional outcome by approximately 8-14%, underscoring the urgency of immediate endovascular treatment 1, 2.
• Door-to-groin puncture should occur within 60 minutes of imaging completion, and unnecessary delays worsen outcomes 1, 2.

Technical Execution

• The angiographic goal should be TICI 2b/3 reperfusion to maximize functional outcomes 3, 4.
• Use stent-retrievers in combination with aspiration techniques for optimal first-pass reperfusion 3, 1, 2.

Critical Pitfall to Avoid

• "Patient overselection" is a major error: unnecessarily restrictive criteria or delays based on symptom resolution worsen outcomes when imaging demonstrates persistent occlusion with salvageable tissue 1.
• Do not withhold thrombectomy based solely on clinical improvement; the imaging findings (persistent occlusion + small core) dictate treatment 1, 2.

Post-Procedure Management

• Maintain blood pressure ≤180/105 mmHg for 24 hours after thrombectomy to reduce hemorrhagic complications 1.