Please select the eligibility criteria that correspond to the clinical trial below.
Title: Mechanical Retrieval and Recanalization of Stroke Clots Using Embolectomy
Brief Summary: The purpose of this study is to compare the effectiveness of treating acute ischemic stroke with mechanical embolectomy using the Merci Retriever or the Penumbra System within 8 hours of symptom onset to standard medical treatment, and to identify people who might benefit from mechanical embolectomy by the appearance of stroke on multimodal computerized tomography (CT) or magnetic resonance (MR) imaging.


Options:
A: Inclusion Criteria:

1. Patients presenting with anterior circulation acute ischaemic stroke eligible using standard criteria to receive IV tPA within 4.5 hours of stroke onset
2. Patient, family member or legally responsible person depending on local ethics requirements has given informed consent
3. Patient"s age is ≥18 years
4. Intra-arterial clot retrieval treatment can commence (groin puncture) within 6 hours of stroke onset.

   Imaging inclusion criteria

   Dual target:
5. Arterial occlusion on CTA or MRA of the ICA, M1 or M2
6. Mismatch - Using CT or MRI with a Tmax \>6 second delay perfusion volume and either CT-rCBF or DWI infarct core volume. a) Mismatch ratio of greater than 1.2, and b) Absolute mismatch volume of greater than 10 ml, and. c) Infarct core lesion volume of less than 70mL

Exclusion Criteria:

1. Intracranial haemorrhage (ICH) identified by CT or MRI
2. Rapidly improving symptoms at the discretion of the investigator
3. Pre-stroke mRS score of ≥ 2 (indicating previous disability)
4. Inability to access the cerebral vasculature in the opinion of the neurointerventional team
5. Contra indication to imaging with MR with contrast agents
6. Participation in any investigational study in the previous 30 days
7. Any terminal illness such that patient would not be expected to survive more than 1 year
8. Any condition that, in the judgment of the investigator could impose hazards to the patient if study therapy is initiated or affect the participation of the patient in the study.
9. Pregnant women
10. Previous stroke within last three months
11. Recent past history or clinical presentation of ICH, subarachnoid haemorrhage (SAH), arterio-venous (AV) malformation, aneurysm, or cerebral neoplasm. At the discretion of each Investigator.
12. Current use of oral anticoagulants and a prolonged prothrombin time (INR \> 1.6)
13. Use of heparin, except for low dose subcutaneous heparin, in the previous 48 hours and a prolonged activated partial thromboplastin time exceeding the upper limit of the local laboratory normal range.
14. Use of glycoprotein IIb - IIIa inhibitors within the past 72 hours. Prior use of single or dual agent oral platelet inhibitors (clopidogrel and/or low-dose aspirin) is permitted.
15. Clinically significant hypoglycaemia.
16. Uncontrolled hypertension defined by a blood pressure \> 185 mmHg systolic or \>110 mmHg diastolic on at least 2 separate occasions at least 10 minutes apart, or requiring aggressive treatment to reduce the blood pressure to within these limits. The definition of "aggressive treatment" is left to the discretion of the responsible Investigator.
17. Hereditary or acquired haemorrhagic diathesis
18. Gastrointestinal or urinary bleeding within the preceding 21 days
19. Major surgery within the preceding 14 days which poses risk in the opinion of the investigator.
20. Exposure to a thrombolytic agent within the previous 72 hrs
B: Inclusion Criteria:

* Sudden focal neurological deficit attributable to a stroke
* Clearly defined time of onset, allowing initiation of intravenous treatment within 3 hours of symptoms onset and intra-arterial treatment within 6 hour of symptoms onset.
* Age greater than 18 years

Exclusion Criteria:

* Disability preceding stroke consistent with a modified Rankin scale score of 2-4
* Coma at onset
* Rapidly improving neurological deficit
* Seizure at onset
* Clinical presentation suggestive of a subarachnoid hemorrhage
* Previous history of intracranial hemorrhage
* Septic embolism
* Arterial puncture at a non compressible site within the previous 7 days
* Any traumatic brain injury within the previous 14 days
* Surgery of the central nervous system in the previous 3 months
* Gastrointestinal hemorrhage or urinary tract hemorrhage within the previous 14 days.
* Current therapy with intravenous or subcutaneous heparin to rise the clotting time
* Known hereditary or acquired hemorrhagic diathesis, baseline INR greater than 1.5, aPTT more than 1.5 times normal, or baseline platelet count less than 100,000 per cubic millimeter
* Baseline blood glucose concentrations below 2.75 mm/L (50 mg/dL).
* Known contrast sensitivity.
* Women of childbearing potential (unless pregnancy impossible) or known to be breastfeeding. Uncontrolled hypertension defined by a blood pressure greater or equal 185 mmHg systolic or diastolic greater or equal 110 mm Hg in 3 separate occasions at least 10 minutes apart or requiring continuous IV therapy.
* Prognosis very poor regardless of therapy; likely to be dead within months.
* Unlikely to be available for follow-up (eg, no fixed home address, visitor from overseas).
* Any other condition which local investigators feels would pose a significant hazard in terms of risk/benefit to the patient, or if therapies are impracticable.

COMPUTED TOMOGRAPHIC (CT) SCAN EXCLUSION CRITERIA

* Intracranial tumors except small meningioma
* Hemorrhage of any degree
* Acute infarction (since this may be an indicator that the time of onset is uncorrected)
C: Inclusion Criteria A. Clinical (Heterogeneous sampling frame)

1. Acute ischemic stroke
2. Age 18 or greater
3. Onset (last-seen-well) time to randomization time \< 12 hours.
4. Disabling stroke defined as a baseline NIHSS \> 5 at the time of randomization.
5. Pre-stroke (24 hours prior to stroke onset) independent functional status in activities of daily living with modified Barthel Index \> 90. Patient must be living in their own home, apartment or seniors lodge where no nursing care is required.

   B. Imaging (Homogeneous target population)
6. Confirmed symptomatic intracranial occlusion, based on single phase, multiphase or dynamic CTA, at one or more of the following locations: Carotid T/L, M1 MCA, or M1-MCA equivalent (2 or more M2-MCAs). Anterior temporal artery is not considered an M2.
7. Non-contrast CT and CTA for trial eligibility performed or repeated at ESCAPE stroke center with endovascular suite on-site.
8. Endovascular treatment intended to be initiated (groin puncture) within 60 minutes of baseline non-contrast CT with target baseline non-contrast CT to first recanalization of 90 minutes.
9. Signed informed consent or appropriate signed deferral of consent where approved.

Exclusion Criteria

1. Baseline non-contrast CT reveals a moderate/large core defined as extensive early ischemic changes of ASPECTS 0-5 in the territory of symptomatic intracranial occlusion.
2. Other confirmation of a moderate to large core defined one of three ways:

   1. On a single phase, multiphase or dynamic CTA: no or minimal collaterals in a region greater than 50% of the MCA territory when compared to pial filling on the contralateral side (multiphase/dynamic CTA preferred) OR
   2. On CT perfusion (\>8 cm coverage): a low CBV and very low CBF ASPECTS \<6 AND in the symptomatic MCA territory OR
   3. On CT perfusion(\<8 cm coverage): a region of low CBV and very low CBF \>1/3 of the CTP imaged symptomatic MCA territory.
3. Groin puncture is not possible within 60 minutes of the first slice of non-contrast CT acquisition (please note that if CTP is performed it should be done after CTA).
4. No femoral pulses or very difficult endovascular access that will result in a non-contrast CT-to-recanalization time that is longer than 90 minutes, or will result in an inability to deliver endovascular therapy.
5. Pregnancy; if a woman is of child-bearing potential a urine or serum beta HCG test is positive.
6. Severe contrast allergy or absolute contraindication to iodinated contrast.
7. Suspected intracranial dissection as a cause of stroke.
8. Clinical history, past imaging or clinical judgment suggests that the intracranial occlusion is chronic.
9. Patient has a severe or fatal comorbid illness that will prevent improvement or follow-up or that will render the procedure unlikely to benefit the patient.
D: Inclusion Criteria:

* New focal disabling neurologic deficit consistent with acute cerebral ischemia (NIHSS \>/= 6)
* Age \>/= 18 ≤ 85
* Clot retrieval procedure can be initiated within 8 hours from onset
* Large vessel proximal anterior circulation occlusion on MR or CT angiography (internal carotid, M1 or M2 MCA)
* Pretreatment MRI performed according to MR RESCUE protocol
* Signed informed consent obtained from the patient or patient's legally authorized representative
* Premorbid modified Rankin score of 0-2
* Allowed but not required: patients treated with IV tPA (tissue plasminogen activator) up to 4.5 hours from symptom onset with persistent target occlusion on post-treatment MR RESCUE MR or CT protocol performed at the completion of drug infusion (Note: Rapidly improving neurological signs prior to randomization is an exclusion)

Exclusion Criteria:

* NIHSS \>/= 30
* Contraindication to MRI (pacemaker etc)
* Acute intracranial hemorrhage
* Coma
* Rapidly improving neurological signs prior to randomization
* Pre-existing medical, neurological or psychiatric disease that would confound the neurological, functional, or imaging evaluations
* Pregnancy
* Known allergy to iodine previously refractory to pretreatment medications
* Current participation in another experimental treatment protocol
* Contrast-Enhanced Neck MRA (magnetic resonance angiography) or CTA (computed tomography angiography) suggests proximal ICA occlusion, proximal carotid stenosis \> 67%, or dissection
* INR \> 3.0 (international normalized ratio)
* PTT \> 3 x Normal (partial thromboplastin time)
* Imaging data cannot be processed by the MR RESCUE computer
* Renal Failure (serum creatinine \> 2.0 or Glomerular Filtration Rate \[GFR\] \< 30)

MRI Exclusion Criteria:

* Contraindication to MRI (pacemaker, etc)

CT Exclusion Criteria:

* Contraindication to iodinated contrast\*\*

  \*\*Examples of possible iodinated contrast contraindications include:
* Hyperthyroidism
* History of severe allergic reaction to iodinated contrast material
* History of sever kidney disease as an adult, including tumor or transplant surgery, or family history of kidney failure
* Paraproteinemia syndromes or multiple myeloma
* Collagen vascular disease
* Severe cardiac insufficiency
* Severely compromised liver function
* Current therapy with metformin, aminoglycosides

Answer: D