Prolonged intracranial catheter dwell time exacerbates penumbral stress and worsens stroke thrombectomy outcomes.

Background: The duration of mechanical thrombectomy (MT) is a negative predictor of outcomes in acute ischemic stroke (AIS), yet the precise mechanisms are unclear. We investigated whether the placement of large-bore catheters intracranially reduces blood flow to the ischemic penumbra and diminishes the efficacy of MT.

Methods: We investigated the impact of different catheter sizes on flow through the intracranial circulation using an in vitro model. Data from a multicenter international registry of AIS patients undergoing MT between January 2016 and December 2023 were reviewed. Intracranial procedure time (icPT) from catheter placement to thrombectomy completion was analyzed using propensity score (PS) matched analysis of patients with successful recanalization achieved in <30 min versus ≥30 min (n=1006/group). Primary outcome was modified Rankin Scale (mRS) score at 90 days (mRS 0-2 favorable). Secondary outcomes included mortality, symptomatic intracranial hemorrhage (sICH), and need for craniectomy.

Results: Using our flow model, we demonstrated a significant reduction in middle cerebral artery and anterior cerebral artery blood flow with the use of larger caliber catheters in the internal carotid artery. Controlling for covariates in 3318 patients, longer icPT predicted lower odds of 90-day favorable outcome (adjusted odds ratio (aOR) 0.87, P<0.01), increased mortality (aOR 1.03, P<0.01), higher decompressive craniectomy rates (aOR 1.07, P<0.01), and increased sICH (aOR 1.07, P<0.01). Each additional 10 mins of icPT correlated with a 13% decrease in recanalization success. The impact of icPT on outcomes was consistent regardless of recanalization success, though catheter size influenced effects. Reduced intraprocedural blood pressure worsened icPT's effects.

Conclusions: This study is the first to demonstrate the risks associated with the duration of catheter use during MT and to propose strategies to mitigate these risks in AIS.