Immediate Intravenous Alteplase and Mechanical Thrombectomy for Acute M1 Occlusion

IV Alteplase Administration

Administer IV alteplase (0.9 mg/kg, 10 % bolus then 90 % infusion over 60 min) immediately, without waiting for thrombectomy preparation, in any patient who meets eligibility for both therapies. This rapid approach is supported by the International Journal of Stroke (2015) and Stroke (2015) studies. [1][2]3
Do not delay the start of alteplase to assess endovascular eligibility; the infusion should begin while the angiography suite is being prepared. Evidence from the same 2015 stroke literature emphasizes concurrent workflow to minimize door‑to‑needle time. [1][2]3
Do not wait for a clinical response to alteplase before proceeding to catheter angiography; patients should be taken directly to the angio suite after the infusion is started. The Stroke (2015) trial demonstrated improved outcomes with this “no‑wait” strategy. 3
Maintain systolic/diastolic blood pressure < 185/110 mmHg before alteplase and keep it < 180/105 mmHg during and after infusion. Blood‑pressure thresholds are outlined in the International Journal of Stroke (2015). [1][2]
Delay antiplatelet therapy for at least 24 hours after alteplase and obtain a follow‑up non‑contrast CT before initiating aspirin. This safety recommendation is drawn from International Journal of Stroke (2015). 1

Endovascular therapy with stent‑retriever devices is the standard of care for M1‑segment occlusions, achieving 72–88 % successful recanalization and a number‑needed‑to‑treat of 3–4 for one additional good functional outcome. These figures are reported in the Stroke (2015) focused update. 3
All major 2015 thrombectomy trials (MR CLEAN, ESCAPE, SWIFT‑PRIME, EXTEND‑IA, REVASCAT) demonstrated that patients eligible for IV alteplase should receive it even when thrombectomy is planned, as the therapies are complementary. The combined evidence from International Journal of Stroke (2015) and Stroke (2015) underpins this recommendation. [1][3]

A non‑contrast CT must exclude intracranial hemorrhage and show early ischemic changes involving ≤ 1/3 of the middle cerebral artery territory (ASPECTS ≥ 6). This imaging criterion is required before alteplase administration per International Journal of Stroke (2015) and Stroke (2015). [2][3]
Perfusion imaging demonstrating a small ischemic core and a large penumbra (e.g., core ≤ 30 mL, mismatch ≥ 20 %) qualifies patients for extended‑window thrombolysis, as endorsed by Canadian Stroke Best Practice (2015). The guideline provides Level B evidence for this selection. 2

Absolute contraindications regardless of time window: platelet count < 100 000 /mm³ or INR > 1.7. These laboratory thresholds are stipulated in Stroke (2015). 3
Current use of direct oral anticoagulants (e.g., apixaban, rivaroxaban, dabigatran) is an absolute contraindication to alteplase because of markedly increased bleeding risk. This is highlighted in International Journal of Stroke (2015). 1
Extensive early ischemic changes (ASPECTS < 6) constitute an absolute contraindication, as they predict higher hemorrhagic transformation risk. Both International Journal of Stroke (2015) and Stroke (2015) support this cutoff. [2][3]

American Heart Association/American Stroke Association (AHA/ASA) 2015 focused update gives a Class I, Level A recommendation that patients eligible for intravenous r‑tPA should receive it even when endovascular therapy is being considered. This high‑grade recommendation underlies the combined‑therapy approach. 3
The same AHA/ASA update provides Level A evidence for combined IV alteplase and mechanical thrombectomy in M1 occlusions treated within 6 hours of symptom onset. 3
Canadian Stroke Best Practice (2015) supplies Level B evidence that a perfusion mismatch of ≥ 20 % with a small‑to‑moderate ischemic core (ASPECTS ≥ 6) justifies treatment beyond the conventional 4.5‑hour window. 2

For acute ischemic stroke, the American College of Cardiology recommends using IV tPA as first-line therapy within 4.5 hours of symptom onset for eligible patients, and adding mechanical thrombectomy for large vessel occlusions, as these are complementary therapies 4, 5
Administer IV tPA (0.9 mg/kg, maximum 90 mg) immediately if the patient meets NINDS inclusion/exclusion criteria, which is a Level A recommendation with the strongest evidence, providing an absolute benefit of 12% more patients achieving minimal or no disability (NNT=8) 6, 7
The American College of Chest Physicians gives a Grade 2C recommendation for offering IV tPA to carefully selected patients meeting ECASS III criteria within 3-4.5 hours of symptom onset, with a smaller benefit (NNT=14 for favorable outcome) and symptomatic ICH risk of NNH=23 7, 8
Do not administer IV tPA beyond 4.5 hours from symptom onset, as this is a Grade 1B recommendation against use, but consider intraarterial thrombolysis for proximal cerebral artery occlusions within 6 hours (Grade 2C) 4, 9

For large vessel occlusions, mechanical thrombectomy is an option for carefully selected patients, particularly when presenting within 6-12 hours with favorable imaging, and should be used in conjunction with tPA without delaying door-to-needle time 9
Proceed with tPA if combined infarct volume does not exceed one-third of MCA territory equivalent across all lesions, and assess for hemorrhagic transformation using imaging 9

Never give tPA to patients on direct oral anticoagulants (DOACs) like apixaban due to substantially elevated bleeding risk, and avoid tPA in cases of hemorrhagic transformation (HI2 or higher) in existing infarcts or extensive early ischemic changes (>1/3 MCA territory) 4, 9
Patients on antiplatelet therapy have a 3% absolute increased risk of symptomatic ICH but can still receive tPA at standard dosing, and baseline symptomatic ICH rate is 4-6% with proper dosing 4

Watch closely for symptomatic ICH in the first 36 hours after tPA administration, and delay antiplatelet therapy for 24 hours after tPA administration 4, 9
Administer aspirin 160-325 mg within 24-48 hours for patients not receiving anticoagulation (Grade 1A), and consider dual antiplatelet therapy (aspirin plus clopidogrel) for 21 days for minor stroke or high-risk TIA when initiated within 12-24 hours 5, 9

Engage in shared decision-making with patients/surrogates before administering tPA, discussing both benefits and harms, and provide realistic expectations about the absolute benefit and potential risks, including symptomatic ICH 7, 8
Patients with NIHSS 5-22 show the most benefit from tPA, and mild to moderate strokes (NIHSS <20) and patients <75 years have the greatest potential for excellent outcomes 4, 8