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. Age ≥18 years;
2. Acute ischemic stroke consistent with infarction in the basilar artery territory;
3. Basilar artery occlusion confirmed by CTA/MRA/DSA, within 8 hours of estimated occlusion time;
4. Written informed consent from patient or surrogate, if unable to provide consent.

Exclusion Criteria:

1. Computed tomography (CT) or Magnetic Resonance Imaging (MRI) evidence of Cerebral hemorrhage on presentation;
2. Premorbid mRS ≥ 3 points;
3. Currently in pregnant or lactating;
4. Known serious sensitivity to radiographic contrast agents and nitinol metal;
5. Current participation in another investigation drug or device study;
6. Uncontrolled hypertension defined as systolic blood pressure \> 185 mmHg or diastolic blood pressure \> 110 mmHg that cannot be controlled except with continuous parenteral antihypertensive medication;
7. Known hereditary or acquired hemorrhagic diathesis, coagulation factor deficiency; or oral anticoagulant therapy with INR \>1.7 or institutionally equivalent prothrombin time;
8. Baseline lab values: glucose \< 50 mg/dl or \> 400 mg/dl, platelets \<100\*109/L, or Hct\<25%;
9. Arterial tortuosity that would prevent the device from reaching the target vessel;
10. Life expectancy less than 1 year;
11. History of major hemorrhage in the past 6 months;
12. Angiographic evidence of significant cerebellar mass effect or acute hydrocephalus.
13. Angiographic evidence of bilateral extended brainstem ischemia.
B: Inclusion Criteria:

* Age greater than or equal to 18
* NIHSS greater than or equal to 8
* onset of symptoms is less than 5 hours OR symptom/imaging mismatch
* suspected occlusion of the M1 or M2 segment of the MCA, supraclinoid ICA, or basilar trunk.

Exclusion Criteria:

* established infarction of the target symptomatic territory
* co-morbid diseases which suggest a poor 90 day outcome irrespective of management
* radiologic evidence of hemorrhagic transformation of the infarcted territory
C: 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
D: Clinical Inclusion Criteria:

1. Signs \& symptoms consistent w/ the diagnosis of acute anterior circulation ischemic stroke
2. Age 18-90 years
3. Baseline NIHSSS is ≥ 6 and remains ≥6 immediately prior to randomization
4. Endovascular treatment can be initiated (femoral puncture) between 6 and 16 hours of stroke onset. Stroke onset is defined as the time the patient was last known to be at their neurologic baseline (wake-up strokes are eligible if they meet the above time limits).
5. modified Rankin Scale less than or equal to 2 prior to qualifying stroke (functionally independent for all ADLs)
6. Patient/Legally Authorized Representative has signed the Informed Consent form.

Clinical Exclusion Criteria:

1. Other serious, advanced, or terminal illness (investigator judgment) or life expectancy is less than 6 months.
2. Pre-existing medical, neurological or psychiatric disease that would confound the neurological or functional evaluations
3. Pregnant
4. Unable to undergo a contrast brain perfusion scan with either MRI or CT
5. Known allergy to iodine that precludes an endovascular procedure
6. Treated with tPA \>4.5 hours after time last known well
7. Treated with tPA 3-4.5 hours after last known well AND any of the following; age \>80, current anticoagulant use, history of diabetes or prior stroke, NIHSS \>25
8. Known hereditary or acquired hemorrhagic diathesis, coagulation factor deficiency; recent oral anticoagulant therapy with INR \> 3 (recent use of one of the new oral anticoagulants is not an exclusion if estimated GFR \> 30 ml/min).
9. Seizures at stroke onset if it precludes obtaining an accurate baseline NIHSS
10. Baseline blood glucose of \<50mg/dL (2.78 mmol) or \>400mg/dL (22.20 mmol)
11. Baseline platelet count \< 50,000/uL
12. Severe, sustained hypertension (Systolic BP \>185 mmHg or Diastolic BP \>110 mmHg)
13. Current participation in another investigational drug or device study
14. Presumed septic embolus; suspicion of bacterial endocarditis
15. Clot retrieval attempted using a neurothrombectomy device prior to 6 hrs from symptom onset
16. Any other condition that, in the opinion of the investigator, precludes an endovascular procedure or poses a significant hazard to the subject if an endovascular procedure was performed.

Neuroimaging Inclusion Criteria:

1. ICA or MCA-M1 occlusion (carotid occlusions can be cervical or intracranial; with or without tandem MCA lesions) by MRA or CTA

   AND
2. Target Mismatch Profile on CT perfusion or MRI (ischemic core volume is \< 70 ml, mismatch ratio is \>/= 1.8 and mismatch volume\* is \>/= 15 ml)

Alternative neuroimaging inclusion criteria (if perfusion imaging or CTA/MRA is technically inadequate):

A) If CTA (or MRA) is technically inadequate:

Tmax\>6s perfusion deficit consistent with an ICA or MCA-M1 occlusion AND Target Mismatch Profile (ischemic core volume is \< 70 ml, mismatch ratio is \>1.8 and mismatch volume is \>15 ml as determined by RAPID software)

B) If MRP is technically inadequate:

ICA or MCA-M1 occlusion (carotid occlusions can be cervical or intracranial; with or without tandem MCA lesions) by MRA (or CTA, if MRA is technically inadequate and a CTA was performed within 60 minutes prior to the MRI) AND DWI lesion volume \< 25 ml

C) If CTP is technically inadequate:

Patient can be screened with MRI and randomized if neuroimaging criteria are met.

Neuroimaging Exclusion Criteria:

1. ASPECTS score \<6 on non-contrast CT (if patient is enrolled based on CT perfusion criteria)
2. Evidence of intracranial tumor (except small meningioma) acute intracranial hemorrhage, neoplasm, or arteriovenous malformation
3. Significant mass effect with midline shift
4. Evidence of internal carotid artery dissection that is flow limiting or aortic dissection
5. Intracranial stent implanted in the same vascular territory that precludes the safe deployment/removal of the neurothrombectomy device
6. Acute symptomatic arterial occlusions in more than one vascular territory confirmed on CTA/MRA (e.g., bilateral MCA occlusions, or an MCA and a basilar artery occlusion).

Answer: C