What is the treatment for ischemic stroke involving the Middle Cerebral Artery (MCA)?

Treatment of Ischemic Stroke Involving the Middle Cerebral Artery (MCA)

Immediate Reperfusion Therapy (Time-Critical)

For MCA territory ischemic stroke, intravenous alteplase (rtPA) within 3 hours of symptom onset combined with mechanical thrombectomy for large vessel occlusion provides the best chance of functional independence and survival. 1, 2

Intravenous Thrombolysis (0-4.5 Hour Window)

• Administer IV alteplase 0.9 mg/kg (maximum 90 mg) for eligible patients within 3 hours of symptom onset, with 10% given as bolus and remainder over 60 minutes 1, 2
• Treatment can extend to 4.5 hours in selected patients, though evidence is strongest within 3 hours 2
• Maintain blood pressure <180/105 mmHg during and for 24 hours after thrombolysis to minimize hemorrhagic transformation risk 1, 2
• Do not administer aspirin or other antithrombotics for 24 hours after rtPA 1, 2
• Symptomatic intracranial hemorrhage occurs in 7% of treated patients versus 1.1% in placebo 3

Mechanical Thrombectomy (0-24 Hour Window)

• Perform endovascular thrombectomy with stent retrievers for angiographically confirmed MCA occlusion within 6 hours of symptom onset 1, 2
• Treatment window extends to 24 hours if perfusion imaging demonstrates salvageable penumbra 1, 2
• Stent retrievers are the preferred device (Class I, Level A evidence), achieving 66% recanalization rates versus 18% with medical therapy alone 3, 2
• Target TICI grade 2b/3 reperfusion for optimal functional outcomes 2
• Do not delay thrombectomy to assess clinical response to IV rtPA - both therapies should proceed simultaneously when indicated 2

Intra-Arterial Thrombolysis (Alternative for 3-6 Hour Window)

• For patients presenting 3-6 hours after symptom onset with MCA occlusion, intra-arterial recombinant pro-urokinase (9 mg) plus low-dose IV heparin provides 15% absolute benefit in achieving modified Rankin Scale ≤2 at 90 days 3
• Median time to treatment in PROACT-II was 5.3 hours, with number needed to treat of 7 for mild or no disability 3
• Patients with NIHSS 11-20 benefit most from this approach 3

Surgical Decompression for Malignant MCA Infarction

Decompressive hemicraniectomy within 48 hours reduces mortality by 50% in patients ≤60 years with massive MCA territory infarction and neurological deterioration. 3, 1

Patient Selection Criteria

• Age ≤60 years: Perform decompressive craniectomy with dural expansion (Class IIa, Level A) - reduces mortality from 78% to 29%, with 55% achieving moderate disability (mRS 2-3) and 18% achieving independence (mRS ≤2) at 12 months 3, 1
• Age >60 years: Consider surgery (Class IIb, Level B-R) - reduces mortality from 76% to 42%, but only 11% achieve moderate disability and none achieve independence at 12 months 3
• Timing: Operate within 48 hours of symptom onset when decreased level of consciousness occurs from brain swelling 3, 1
• Imaging criteria: Large territorial infarction with midline shift and clinical deterioration despite medical management 3

Medical Management of Cerebral Edema

• Osmotic therapy with mannitol (0.25-0.50 g/kg IV over 20 minutes every 6 hours) is reasonable for clinical deterioration from cerebral swelling 3
• Monitor serum and urine osmolality during mannitol therapy 3
• Brief moderate hyperventilation (PaCO2 30-34 mmHg) as bridge to definitive therapy for acute severe neurological decline 3
• Do not use hypothermia or barbiturates for ischemic cerebral swelling (Class III: No Benefit) 3
• Prophylactic anticonvulsants are not recommended 3, 1

Post-Acute Medical Management

Antiplatelet Therapy

• Administer aspirin 160-325 mg within 24-48 hours of stroke onset (but delay 24 hours if rtPA was given) 1, 2
• This provides small but meaningful reduction in early recurrent stroke 1

Blood Pressure Management

• Maintain permissive hypertension unless BP >220/120 mmHg in patients not receiving acute reperfusion therapy 1, 2
• Aggressive BP lowering can worsen cerebral perfusion to ischemic penumbra 1
• For thrombectomy patients, keep BP ≤180/105 mmHg during and for 24 hours after procedure 2

Monitoring and Supportive Care

• Admit to specialized stroke unit with continuous cardiac monitoring for ≥24 hours to detect atrial fibrillation 1
• Aggressively treat fever >38°C, as hyperthermia worsens outcomes 1
• Control blood glucose carefully, avoiding both hyper- and hypoglycemia 1
• Initiate early mobilization and intermittent pneumatic compression for DVT prophylaxis 1

Diagnostic Imaging Requirements

Immediate Non-Contrast CT (Within 25 Minutes)

• Obtain non-contrast CT brain immediately to exclude hemorrhage before any reperfusion therapy 3, 1, 4
• Look for hyperdense MCA sign (present in 54% on CT, 82% on MRI gradient echo), loss of gray-white differentiation in insular cortex, lentiform nucleus attenuation, and sulcal effacement 3, 4
• Early infarct signs involving >1/3 MCA territory increase hemorrhagic risk 8-fold but do not exclude rtPA treatment within 3 hours 3, 1, 4
• CT sensitivity is only 50% in first hours, so normal CT does not exclude acute stroke 4

CT Angiography

• Obtain CT angiography to identify large vessel occlusion for thrombectomy candidacy 1, 2
• Do not delay thrombolytic therapy to obtain CTA if patient is otherwise eligible within 3-hour window 4

Critical Pitfalls to Avoid

• Never delay IV rtPA to obtain MRI when CT is immediately available and patient is within thrombolysis window 1
• Never routinely anticoagulate acute ischemic stroke patients - this increases hemorrhagic transformation risk 1
• Never wait to assess rtPA response before pursuing thrombectomy - both should proceed simultaneously when indicated 2
• Never use prophylactic anticonvulsants in stroke patients who have not had seizures 3, 1
• Do not exclude patients from rtPA based solely on >1/3 MCA territory involvement if within 3-hour window and otherwise eligible 3, 1
• Physician accuracy in detecting >1/3 MCA involvement is only 70-80%, so clinical judgment must incorporate multiple factors 4

Secondary Prevention Workup

• Obtain carotid duplex ultrasound urgently for all patients with carotid territory symptoms who are potential revascularization candidates 1
• Perform transthoracic echocardiography to identify cardioembolic sources 1
• Extended cardiac monitoring beyond initial 24 hours to detect paroxysmal atrial fibrillation 1