Thrombectomy for Stroke at 6-24 hours without Perfusion CT Software for Patient Selection

Area of Science:

• Neurology
• Interventional Radiology
• Public Health

Background:

• Mechanical thrombectomy is a proven stroke treatment, but advanced imaging software (e.g., RAPID) is not universally available.
• In Japan, access to advanced perfusion CT software for stroke treatment selection is limited.
• This necessitates evaluating alternative methods for identifying suitable patients for thrombectomy outside the standard 6-hour window.

Purpose of the Study:

• To evaluate the efficacy of mechanical thrombectomy for acute ischemic stroke patients between 6 and 24 hours after symptom onset.
• To determine if conventional imaging mismatch criteria can identify patients who benefit from late thrombectomy.
• To assess functional outcomes and mortality rates in this patient cohort.

Main Methods:

• Retrospective analysis of 31 ischemic stroke patients who underwent thrombectomy between 6-24 hours after last known well.
• Patients had intracranial internal carotid artery or middle cerebral artery occlusion and prestroke mRS score of 0-1.
• Outcomes measured by utility-weighted modified Rankin Scale (UW-mRS) and functional independence (mRS 0-2) at 90 days.

Main Results:

• The median time from last known well to revascularization was 741 minutes.
• The mean UW-mRS score at 90 days was 5.3.
• Functional independence was achieved in 32% of patients, with a 13% 90-day mortality rate.

Conclusions:

• Mechanical thrombectomy using conventional imaging mismatch criteria is a viable option for stroke patients presenting between 6-24 hours after onset.
• This approach may improve functional independence in stroke patients, even without advanced perfusion imaging software.
• Conventional imaging can guide patient selection for extended window thrombectomy, expanding treatment accessibility.