What is the management of large vessel infarct?

Management of Large Vessel Infarct

For acute large vessel occlusion (LVO) stroke, immediate mechanical thrombectomy is the definitive treatment when performed within 24 hours of symptom onset in appropriately selected patients, with IV alteplase (0.9 mg/kg, max 90 mg) administered simultaneously if within 4.5 hours. 1, 2

Prehospital Triage and Recognition

• Transport patients with suspected LVO (RACE score ≥5) directly to a comprehensive stroke center capable of endovascular thrombectomy, as this threshold demonstrates 85% sensitivity for detecting LVO 1
• If the patient arrives at a non-thrombectomy-capable hospital with RACE ≥5, confirm with NIHSS; an NIHSS ≥6 provides 87% sensitivity for LVO and mandates immediate transfer 1
• Recognize that 50-65% of patients with RACE ≥5 will be false positives for LVO, but missing an LVO (false negative) causes far greater harm than unnecessary transfers 1
• A negative RACE score (<5) does not rule out LVO—the probability can still be ≥10%, so maintain standard stroke protocols for all suspected cases 1

Immediate Diagnostic Workup

• Obtain non-contrast CT head plus CT angiography immediately upon arrival to exclude hemorrhage and confirm vessel occlusion 2
• For vertebral artery dissection causing LVO, catheter-based contrast angiography is typically required before revascularization 2
• Assess collateral status on baseline imaging, as absent collaterals correlate with larger final infarct volumes and worse functional outcomes, even in patients with mild symptoms 3, 4

Acute Reperfusion Strategy

Intravenous Thrombolysis

• Administer IV alteplase (0.9 mg/kg, maximum 90 mg) if within 4.5 hours of symptom onset while simultaneously preparing for mechanical thrombectomy 2
• Do not delay thrombectomy to wait for alteplase response 2

Mechanical Thrombectomy

• Proceed with mechanical thrombectomy for anterior circulation LVO within 24 hours of symptom onset when perfusion imaging demonstrates salvageable tissue 5
• For basilar artery occlusion secondary to vertebral dissection with NIHSS ≥6 and PC-ASPECTS ≥6, thrombectomy is indicated within 12 hours (Class I) and reasonable up to 24 hours (Class IIa) 2
• Use the BADDASS technique (balloon guide with large bore distal access catheter with dual aspiration with stent-retriever) as the standard mechanical approach 2
• Target successful reperfusion (mTICI 2b/3), as this is the strongest independent predictor of favorable outcome at discharge, more so than baseline collateral status 4

Time-Sensitive Considerations

• Every 30-minute delay decreases good functional outcome by 8-14%, making speed essential 1
• Patients presenting 6-24 hours after onset with automated perfusion imaging selection showing salvageable tissue achieve similar outcomes to early-presenting patients, though they demonstrate slower infarct growth velocities (median 0.6 vs 5.1 mL/h) 5
• Fast progressors (core >70 mL within 6 hours) represent 25% of LVO patients overall but reach 40% prevalence between 3-4.5 hours after onset 6
• Slow progressors (core ≤30 mL at 6-24 hours) represent 55% of LVO patients and maintain similar prevalence across all time intervals beyond 6 hours 6

Special Populations

Mild Symptoms (NIHSS <6)

• Most patients with anterior circulation LVO and low NIHSS achieve good long-term functional outcome (86%), but approximately 15% develop significant disability 3
• Absent collaterals in mild stroke patients correlate with 25% larger final infarct volume per one-point NIHSS increase and lower odds of good functional outcome (OR 0.96 per mL increase) 3
• Consider mechanical thrombectomy in mild stroke patients with poor collateral scores, as collateral status may identify those who benefit from intervention 3

Vertebral Artery Dissection

• Initiate anticoagulation with IV heparin followed by oral warfarin for at least 3 months in all vertebral artery dissection patients causing acute ischemic stroke, regardless of whether thrombolytic therapy is used 2
• Start anticoagulation immediately after excluding hemorrhagic transformation, even if thrombolytics were administered 2
• Maintain blood pressure <185/110 mmHg when anticoagulation is initiated, using labetalol, nicardipine, or clevidipine 2
• Continue anticoagulation for at least 3 months, then reassess with repeat vascular imaging 2

Critical Pitfalls to Avoid

• Do not use neuroprotective agents (Class III: No Benefit), as no pharmacological or non-pharmacological treatments with putative neuroprotective actions have demonstrated efficacy in improving outcomes after ischemic stroke 7
• Do not delay thrombectomy for patients presenting beyond 6 hours if perfusion imaging demonstrates salvageable tissue—late-presenting patients (6-24 hours) achieve comparable outcomes to early presenters when selected by automated perfusion imaging 5
• Do not assume good collaterals guarantee good outcomes without successful reperfusion—while collateral status affects border zone infarction, achieving mTICI 2b/3 reperfusion is the independent predictor of favorable discharge outcomes 4
• Recognize that poor collateral status predominantly affects middle cerebral artery border zones, while incomplete reperfusion (mTICI 0-2a) causes infarction of deep white matter tracts and posterior limb of internal capsule 4

Population-Level Impact

• LVO strokes account for 38.7% of all acutely presenting ischemic strokes but cause 61.6% of poststroke dependence or death and 95.6% of poststroke mortality 8
• Rates of dependence or death (mRS 3-6) within 3-6 months are dramatically higher after LVO than non-LVO ischemic stroke (64% vs 24%, OR 4.46) 8
• Mortality within 3-6 months is substantially higher after LVO than non-LVO ischemic stroke (26.2% vs 1.3%, OR 4.09) 8