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

Mechanical Thrombectomy (Option B)

For this patient presenting at 12 hours with resolved symptoms but persistent proximal anterior circulation occlusion and small-to-moderate ischemic core on imaging, mechanical thrombectomy alone is the most appropriate management.

Rationale for Mechanical Thrombectomy Over Other Options

Why Not tPA Alone (Option A)

• The patient is beyond the 4.5-hour window for IV tPA monotherapy, making thrombolysis alone inappropriate at 12 hours from symptom onset 1
• IV thrombolysis is more effective for distal thrombi than for proximal large-vessel occlusions, whereas mechanical thrombectomy provides superior efficacy for proximal occlusions 1
• tPA alone would be inadequate given the documented proximal anterior circulation occlusion with salvageable tissue 2

Why Mechanical Thrombectomy Is Indicated (Option B)

• The American Heart Association recommends mechanical thrombectomy for patients within 6-16 hours of last known normal who have large vessel occlusion in the anterior circulation and meet DAWN or DEFUSE-3 eligibility criteria (Class I, Level A recommendation) 3
• The American College of Cardiology reports that 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
• At 12 hours, mechanical thrombectomy remains the primary reperfusion strategy regardless of symptom resolution when favorable imaging demonstrates salvageable tissue 1

Why Not Combined Therapy (Option C)

• While most positive thrombectomy trials included patients who received IV tPA (83.7% in MR CLEAN, 91.5% in ESCAPE), the question states the patient is at 12 hours with normal coagulation profile 2
• The critical factor is that symptoms have resolved, suggesting either a transient ischemic attack with persistent occlusion or spontaneous partial recanalization
• Given the 12-hour time point and resolved symptoms, the urgency is mechanical recanalization of the persistent occlusion rather than adding thrombolytic therapy that carries hemorrhagic risk without clear additional benefit at this time window 1

Why Not Observation (Option D)

• The natural history of untreated proximal occlusions is associated with high morbidity and mortality, and observation would be inappropriate despite symptom resolution 1
• The American College of Cardiology quantifies that each 30-minute delay in achieving recanalization reduces the probability of a good functional outcome by approximately 8%-14% 1
• The presence of a persistent large vessel occlusion with salvageable tissue mandates intervention to prevent stroke recurrence or progression 1

Critical Imaging Requirements at 12 Hours

Before proceeding with thrombectomy, confirm the patient meets extended window criteria:

• Advanced perfusion imaging is essential to confirm salvageable tissue at 12 hours 2
• Patients must demonstrate either DAWN criteria (clinical-imaging mismatch with age <80 years, NIHSS ≥10, and core <31 mL, or NIHSS ≥20 and core <51 mL) or DEFUSE-3 criteria (ischemic core <70 mL, mismatch ratio ≥1.8, and mismatch volume ≥15 mL) 2
• The American Heart Association mandates that only DAWN or DEFUSE-3 eligibility criteria should be strictly adhered to in clinical practice for the 6-24 hour window 3

Technical Goals and Execution

• The angiographic target should be modified TICI 2b/3 reperfusion to maximize functional outcomes 3, 4
• The American College of Cardiology recommends a combined endovascular approach using stent-retrievers together with aspiration to achieve rapid first-pass complete reperfusion 1
• Minimize door-to-groin puncture time, with a target of groin puncture within 60 minutes of CT/CTA completion 2

Critical Pitfalls to Avoid

• Do not delay thrombectomy for unnecessary testing beyond confirming blood glucose and obtaining essential vascular imaging 2
• Do not proceed if imaging shows ASPECTS of 0, no perfusion mismatch, or large established infarct core >70 mL by DEFUSE-3 criteria 2
• The American College of Cardiology cautions against "patient overselection"; unnecessary delays or overly restrictive selection criteria worsen outcomes 1
• Thrombectomy should not be attempted without perfusion imaging in the 6-24 hour window, as tissue selection is mandatory for benefit 4

Post-Procedure Management

• Maintain blood pressure ≤180/105 mmHg for 24 hours after thrombectomy to reduce hemorrhagic complications 2
• Close monitoring for hemorrhagic transformation and other complications in the immediate post-procedure period is essential 2