This population-based retrospective cohort study of endovascular thrombectomy (EVT)-treated acute ischemic stroke in Ontario evaluated whether inter-hospital transfer before EVT is associated with different long-term outcomes compared with direct presentation to a comprehensive stroke center. ^{Reference Murphy, Hong, Fang, Austin, Kapral and Yu1} The authors report a time-varying association with all-cause mortality, with higher early mortality among transferred patients that attenuates and reverses after about 6.3 months, and higher admission to long-term care, with no significant difference in recurrent stroke.

The most compelling finding is the time-varying nature of the mortality hazard. The data show that transferred patients face a higher risk of death in the early post-procedural period, but this risk attenuates and eventually reverses after approximately six months. The authors hypothesize that this late survival benefit may be driven by the selection of “slow progressors” who have better collateral circulation. This is a biologically plausible explanation that warrants validation in future studies and appears consistent with recent work characterizing infarct growth trajectories by Wouters et al and Mohammaden et al. ^{Reference Wouter, Seners and Yuen2,Reference Mohammaden, Haussen and Pisani3} If confirmed, it would suggest that physiological reserves may play a larger role in decision-making to transfer to comprehensive stroke center.

However, the functional outcomes present a sobering counterpoint to the survival findings. Transferred patients were significantly more likely to be admitted to long-term care facilities, creating a divergence in which transferred patients may be more likely to survive long-term but less likely to maintain independence. This finding highlights the potential cost of treatment delays on brain health, even when mortality is reduced. It reinforces the concept that “transfer time is brain,” as emphasized by Seners et al, and is consistent with the association between shorter time-to-treatment and better functional outcome in the MR CLEAN Registry. ^{Reference Seners, Khyheng and Labreuche4,Reference Mulder, Jansen and Goldhorn5} This finding suggests that future evaluation of triage protocols should prioritize patient-centered functional and quality-of-life outcomes alongside survival.

The reliance on administrative data imposes limitations on the granularity of workflow metrics. The absence of onset-to-puncture or door-to-puncture times limits the ability to quantify the contribution of delay to the observed disparities. In addition, the inability to identify patients with large vessel occlusion who did not receive EVT constrains assessment of selection bias inherent to the transfer process. Despite these limitations, the use of propensity score weighting and time-varying hazard modeling provides a rigorous analytical framework. Overall, this study underscores the need to optimize pre-hospital and inter-hospital pathways and raises important questions regarding the long-term burden of disability among survivors who undergo inter-hospital transfer.