Ultra-early Identification of Futile Recanalization After Reperfusion Therapy in Acute Ischemic Stroke Based on Cerebral Autoregulation Monitoring

• NIRS-based cerebral oxygenation and blood pressure monitoring (Device): Bedside multimodal cerebral autoregulation monitoring performed immediately after successful mechanical thrombectomy (mTICI 2b-3). Monitoring includes continuous near-infrared spectroscopy (NIRS) to record cerebral oxygen saturation and continuous noninvasive or invasive arterial blood pressure measurement for 25-30 minutes. Cerebral oxygenation index (COx) is calculated as a moving Pearson correlation coefficient between mean arterial pressure and cerebral oxygen saturation over 30 consecutive 10-second epochs (300 seconds). COx ≥ 0.3 indicates impaired cerebral autoregulation, while COx < 0.3 indicates preserved autoregulation. Changes in cerebral oxygen saturation before and after carotid compression are also used to assess autoregulatory.
• Carotid compression test (Procedure): A carotid compression test is performed by compressing the common carotid artery at the lower one-third of the neck (avoiding the carotid sinus) against the transverse process of C6 until pulsation disappears for 5-10 seconds, followed by release. If the brain oxygen saturation has increased compared to before the test, it indicates that the brain's automatic blood flow regulation function is intact; conversely, if it has decreased, it is regarded as a damaged automatic blood flow regulation function of the brain.

Primary outcomes

• Distribution of Modified Rankin scale [90±7days]: the distribution of Modified Rankin scale (mRS) \[ranging from 0 (normal) to 6 (death)\]

Secondary outcomes

• Early neurological improvement [24±12 hours]: Early neurological improvement is defined as a reduction of ≥8 on the National Institutes of Health Stroke Scale \[ranging from 0 to 42 points, with higher numbers indicating greater severity\] or National nstitutes of Health Stroke Scale zero to one 24 hours after thrombectomy.

Sex: All, ages: 18 Years to any

Inclusion Criteria:

1. Age ≥ 18
2. Diagnosis of acute ischemic stroke caused by anterior circulation large vessel occlusion (intracranial internal carotid artery or M1 segment of the middle cerebral artery).
3. National Institutes of Health Stroke Scale (NIHSS) score ≥ 6 at presentation.
4. Pre-stroke modified Rankin Scale (mRS) score ≤ 1.
5. Symptom onset ≤ 24 hours.
6. For patients with symptom onset within 6 hours: ASPECTS ≥ 6; for patients with symptom onset between 6 and 24 hours: age ≤ 80 years and ASPECTS ≥ 3.
7. Underwent mechanical thrombectomy and achieved successful recanalization (mTICI 2b-3).
8. Patient or legally authorized representative provides written informed consent.

Exclusion Criteria:

1. Pre-procedural baseline imaging showing significant intracranial hemorrhagic transformation, intracranial arterial dissection, large chronic cerebral infarction, or intracranial metastasis from malignant tumors.
2. Any degree of stenosis, plaque, dissection, severe tortuosity, or imaging evidence of unstable/vulnerable plaque in the target-side or bilateral common carotid artery or the origin of the internal carotid artery.
3. Known history of carotid sinus hypersensitivity syndrome, severe autonomic dysfunction, sick sinus syndrome, high-grade atrioventricular conduction block, or other malignant arrhythmias.
4. Refractory malignant hypertensive crisis (systolic blood pressure persistently ≥ 200 mmHg despite standardized intravenous antihypertensive therapy, or hemodynamic instability with shock).
5. Known severe allergy to contrast agents or anesthetic drugs, or contraindications to antiplatelet/anticoagulation therapy.
6. Severe systemic active infection, multiple organ failure, or expected survival < 6 months.
7. Severe hepatic or renal dysfunction (ALT/AST > 3× upper limit of normal; estimated glomerular filtration rate < 30 mL/min) or severe coagulation disorders (platelet count < 40 × 10⁹/L, APTT > 50 s, INR > 3.0).
8. Blood glucose < 2.7 mmol/L or > 22.2 mmol/L.
9. Heart failure with NYHA class > II, or persistent systolic blood pressure < 100 mmHg.
10. Central nervous system infection or intracranial tumor.
11. Unstable vital signs.
12. Severe alcohol dependence or drug dependence.
13. Cognitive impairment or psychiatric disorders that may affect follow-up assessments.
14. Pregnant or breastfeeding women.
15. Participation in another clinical drug or device study within the past 30 days.
16. Local skin damage or other conditions preventing proper placement of monitoring electrodes.
17. Severe agitation or other conditions that interfere with data acquisition.
18. Any other condition judged by investigators to potentially affect study results.

• Shen Li, Principal investigator, Beijing Shijitan Hospital, Capital Medical University