Time-varying relationship between ischemic core volume and outcomes after mechanical thrombectomy

Area of Science:

• Neurology
• Radiology
• Medical Imaging

Background:

• The relationship between ischemic core volume and neurological outcomes after mechanical thrombectomy (MT) is not fully understood.
• Accurate assessment of infarct core size and its evolution is crucial for treatment decisions.

Purpose of the Study:

• To evaluate the time-varying relationship between ischemic core volume and neurological outcomes in patients undergoing MT.
• To develop visual probability heat maps to aid clinical decision-making for MT.

Main Methods:

• Retrospective review of 168 patients who underwent successful MT (mTICI 2b-3).
• Preoperative computed tomography perfusion (CTP) using RAPID software to define ischemic core (<30% relative cerebral blood flow).
• Logistic regression models analyzed the interaction between time from onset to CTP (OTCTP) and core volume, adjusting for covariates; 90-day modified Rankin Scale (mRS) scores assessed outcomes.

Main Results:

• Poor outcomes (mRS 5-6) occurred in 23.8% of patients.
• Outcome probability increased with longer OTCTP, irrespective of core volume.
• A 50 mL ischemic core had poor outcome probabilities of 18% at 3h, 25% at 8h, and 56% at 24h.
• CTP-derived core volumes showed variable agreement with final infarct volumes, with underestimation beyond 6 hours.

Conclusions:

• The prognostic value of CTP-derived ischemic core volume is time-dependent.
• Heat maps can assist in patient selection for MT by illustrating time-varying outcome risks.
• Consideration of time from onset is critical when interpreting ischemic core volume for MT candidacy.