Augmenting Cerebral Blood Flow to Preserve the Penumbra Trial

Inclusion Criteria:

1. Signs & symptoms consistent with the diagnosis of large vessel occlusion in theanterior circulation

2. Age 18-90 years

3. Baseline NIHSS ≥ 10

4. Ability to initiate treatment within 6 hours from stroke onset. Stroke onset isdefined as the time the patient was last seen well.

5. Large vessel total occlusion by CTA

6. Penumbra ≥ 50ml (Difference between Tmax6 volume and the ischemic core volume (CBF<38%volume)

7. Mismatch (Tmax6 volume/ischemic core volume (CBF<38% volume) ≥1.5

8. Core and HIR (Tmax10 / Tmax6) volumes: 1. HIR ≥ 0.5 or 2. 0.35 ≤ HIR < 0.5 and "corevolume/time from onset to imaging" ≥ 7mililiter/hour

9. Signed informed consent from patient him/herself or legally authorized representative.

Exclusion Criteria:

1. Unable to undergo a contrast brain perfusion scan, including an allergy to contrastmedia

2. Opportunity for reperfusion therapy (IV thrombolysis or endovascular treatment)

3. Neuro-imaging evidence of any intracranial hemorrhage or hemorrhagic transformation ofbrain infarct or other significant abnormality (e.g. tumor, abscess, suspect forsubarachnoid hemorrhage, arteriovenous malformation, cerebral aneurysm).

4. Significant mass effect with midline shift.

5. Infarct core volume >150 milliliter

6. Old non-lacunar infarct in the anterior circulation on the ipsilateral hemisphere.

7. Previous stroke in the last 6 months or previous stroke with existing sequelae or withmRS > 0 for any reason

8. Pre-existing Modified Rankin Score >1, even if not stroke-related.

9. Acute symptomatic arterial occlusions in more than one vascular territory confirmed onCTA/MRA (e.g., bilateral MCA occlusions, or an MCA and a basilar artery occlusion).

10. Seizures at stroke onset

11. Baseline blood glucose of <50mg/dL (2.78 mmol) or >400mg/dL (22.20 mmol)

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. Clinical signs and symptoms or evidence for a relevant lesion by neuro-imaging of anacute ischemic stroke in the posterior circulation (Vertebral, Basilar and/orPosterior Cerebral Artery territories), including but not limited to brain-stemfindings and/or cerebellar findings and/or isolated homonymous hemianopia or corticalblindness.

16. Patients with bleeding propensity and/or one of the following: INR > 1.8, prolongedactivated partial thromboplastin time (aPTT) ≥ 45 sec., platelets count < 75×10^9/L.

17. Serious systemic infection.

18. Women known to be pregnant or having a positive or indeterminate pregnancy test.

19. Patients with other implanted neural stimulator/ electronic devices (pacemakers).

20. History of SPG ablation ipsilateral to the stroke side.

21. Any condition in the oral cavity that prevents implantation of the INS.

22. Known sensitivity to any medications to be used during study.

23. Subjects who have a clinically significant or unstable medical or surgical conditionthat may preclude safe and complete study participation. Conditions may include:cardiovascular, vascular, pulmonary, hepatic, renal or neurological (other than acuteischemic stroke), or neoplastic diseases, as determined by medical history, physicalexamination, laboratory tests, or ECG.

24. Subjects who, in the judgment of the investigator, are likely to be non-compliant oruncooperative during the study.