Tolga D. Dittrich, MD

Maslias E, Nannoni S, Ricciardi F, Bartolini B, Strambo D, Puccinelli F, Hajdu SD, Eskandari A, Saliou G, Michel P. Procedural Complications During Early Versus Late Endovascular Treatment in Acute Stroke: Frequency and Clinical Impact. Stroke. 2021;52:1079–1082.

The efficacy of endovascular treatment (EVT) for patients with acute ischemic stroke due to proximal vessel occlusion is well established. This holds for patients in the early (<6 hours after symptom onset) and radiologically preselected patients in the late time window (6-24 hours). Randomized controlled trials showed a reasonable overall safety profile, with a relatively wide range (2.4-7%) of reported intraprocedural cerebrovascular complications. These complications include embolization in the non-ischemic territory, arterial dissections, and perforations.

In their monocenter retrospective analysis of 695 stroke patients receiving EVT, Maslias and colleagues examined the incidence of intraprocedural complications and their implications for short-term outcomes in the early (N=493) and late time window (N=202). The overall proportion of patients with at least one intraprocedural complication was relatively high across both groups (16.2% in the early, 16.3% in the late window, Padj=0.90). This might be surprising given the intuitive concern of increased intraprocedural complication rates in the late time window (e.g., due to increased permeability of the vessel walls with longer-lasting ischemia). Still, the occurrence of intraprocedural complications was associated with a worse outcome, at least in the short term (i.e., within the first 24 hours), at comparable recanalization rates in the late time window.

Considering the relatively high proportion of wake-up stroke patients in the late EVT group (59.9%), the results should be interpreted cautiously. The time window between actual stroke onset and EVT might have been only slightly longer in these individuals compared to the early EVT patients, potentially compromising the discriminatory power between both groups. It remains to be determined whether (and if so, to what extent) these intraprocedural complications affect the long-term outcomes of early and late EVT patients.

The study of Maslias et al. is a critical step in the right direction. The issue of EVT procedure-related complications is highly relevant, especially in light of the successive extension of the EVT window over the last years. The matter is likely to become even more important in the future, considering that ongoing RCTs with more liberal inclusion criteria than DAWN and DEFUSE3 (i.e., larger core) could lead to an expansion of the EVT indication spectrum in the late window, and what about other periprocedural EVT complications such as reperfusion damage or reocclusion in the early versus late window? These questions remain to be addressed.