Related Experiment Video
Updated: Jun 10, 2026
Predicting Amputation using Local Circulating Mononuclear Progenitor Cells in Angioplasty-treated Patients with Critical Limb Ischemia
Published on: September 22, 2020
Mechanisms, predictors, and clinical impact of failed recanalization: a large cohort analysis
Richard Bruen1, Hayley Briody2, Paul McHugh2
1Diagnostic and Interventional Neuroradiology Department, Beaumont Hospital, Dublin, Ireland richardbruen93@gmail.com.
Insights
Technical failure in endovascular thrombectomy (EVT) for stroke is linked to intracranial atherosclerotic disease (ICAD) and access issues. Recognizing ICAD is crucial for improving EVT outcomes in Western populations.
Area of Science:
- Neurology
- Interventional Neuroradiology
- Vascular Neurology
Background:
- Endovascular thrombectomy (EVT) is standard for large vessel occlusion stroke, but technical failures occur.
- Intracranial atherosclerotic disease (ICAD) is a known cause of EVT failure, particularly in Asian populations, but may be underestimated in Western cohorts.
Purpose of the Study:
- To classify mechanisms of technical failure in a large Western cohort undergoing EVT.
- To investigate the impact of unrecognized ICAD and anatomical access difficulties on EVT success.
Main Methods:
- Retrospective analysis of 2467 EVT procedures.
- Failure defined as modified Treatment In Cerebral Infarction (mTICI) <2b or no angiographic improvement.
- Failures categorized into access (type 1), reperfusion (type 2), and aborted/other (type 3), with type 2 adjudicated for ICAD features.
Main Results:
- Overall failure rate was 12.7%, with type 2 (reperfusion failure) being most common (40.6%).
- Failure was associated with longer procedure times and higher in-hospital mortality.
- Likely or possible ICAD was identified in 22.8% of type 2 failures. Access failures (type 1) did not improve over time.
Conclusions:
- Procedural failure in EVT, despite technical advances, has severe consequences.
- A significant proportion of EVT failures in Western patients are attributable to underlying ICAD, not just refractory emboli.
- Persistent challenges in access (type 1 failures) highlight an unmet technical need in EVT.
Background:
Endovascular thrombectomy (EVT) is the standard of care for large vessel occlusion stroke, yet technical failure persists in a significant minority of cases. Intracranial atherosclerotic disease (ICAD) is a recognized driver of failure in Asian populations; its prevalence in Western cohorts is underestimated. We aimed to classify mechanisms of technical failure in a large cohort and investigate the impact of both unrecognized ICAD and anatomical access difficulties.
Methods:
We analyzed 2467 consecutive single-center EVT procedures retrospectively. Failure was defined as final modified Treatment In Cerebral Infarction (mTICI) <2b or no angiographic improvement. Failures were classified into three categories: type 1 (access failure), type 2 (clot accessed but no durable reperfusion), and type 3 (aborted/other). Type 2 failures were adjudicated by consensus to identify features suggestive of ICAD.
Results:
Recanalization failure occurred in 313 patients (12.7%); type 1 accounted for 40 (12.8%), type 2 occurred in 127 (40.6%), and 146 (46.6%) were type 3. Baseline age and stroke severity were similar between successful and failed groups, but failure was associated with significantly longer procedure times (median 60 vs 30 min, P<0.001) and almost threefold higher in-hospital mortality (29.4% vs 11.0%, P<0.001). Among type 2 failures, 18.1% were adjudicated as likely underlying ICAD and 4.7% as possible ICAD. While overall failure rates declined from 23.0% (2012-2015) to 11.2% (2019-2023) driven by improvements in M1 middle cerebral artery recanalization, the incidence of type 1 failures did not significantly improve over time (P=0.20), representing a persistent unmet technical need.
Conclusions:
Despite technical advances, procedural failure remains a distinct event with catastrophic outcomes. Up to 22.8% of retrieval failures in this Western cohort were attributable to likely/possible underlying ICAD rather than refractory emboli.
