Purpose Mechanical thrombectomy (MT) is a highly effective therapy in patients with acute ischemic stroke due to large vessel occlusion (LVO). However, complete recanalization of the occluded vessel cannot be achieved in all patients, leading to poor clinical outcome. We analyzed the reasons for failed recanalization to help direct future improvements in therapy.
Methods 648 consecutive stroke patients with LVO and an MT attempt were retrospectively analyzed for none or minimal recanalization, assessed according to the Thrombolysis in Cerebral Infarction (TICI) score (0/1). Procedural parameters were evaluated in a standardized approach. Among other variables, number of retrieval attempts, devices, duration of the intervention, and rescue methods were analyzed.
Results TICI 0/1 was observed in 72/648 patients (11%). In these patients, the thrombus could not be reached in 21% (n=15/72), was reached but not passed in 21% (n=15/72), and was reached and passed in 58% (n=42/72). Only a minor degree of initial recanalization was achieved in 19% (n=8/42) of patients with a reached occlusion during the course of the intervention. Furthermore, a higher number of passes with a single retriever device led to significant prolongation of the intervention. Therefore, major reasons for failed endovascular recanalization were difficult anatomical access and hard or resistant occlusions that might reflect hard thrombi or pre-existing atherosclerotic stenosis. Procedural complications such as dissection or perforation played a minor role.
Conclusion In stroke patients with failed MT attempts, approximately 60% of occlusions can be passed. In such cases, rescue therapy might be considered to improve recanalization and clinical outcome. Further development of access devices might help in the remaining cases where the microcatheter could not be manipulated to or through the occlusion.
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Contributors HL, FF, UH, CB, and JF made substantial contributions to the conception and design of the work. Data acquisition was performed by HL, FF, CB, GB, MD-C and TF. HH, FF, and JF performed the data analysis. Interpretation of the data was done by HH, FF, J-HB, MB, CB, GT, CG, and JF. HL and JF drafted the manuscript and all of the other authors revised it critically for important intellectual content. All authors approved the final version to be published. They agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the manuscript are appropriately investigated and resolved.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial, or not-for-profit sectors.
Competing interests JF served as a consultant for Acandis, Boehringer Ingelheim, Codman, Microvention, Sequent, and Stryker; speaker for Bayer Healthcare, Bracco, Covidien/ev3, Penumbra, Philips, and Siemens; and received grants from Bundesministeriums für Wirtschaft und Energie (BMWi), Bundesministerium für Bildung und Forschung (BMBF), Deutsche Forschungsgemeinschaft (DFG), European Union (EU), Covidien, Stryker (THRILL study), and Microvention (ERASER study) GT serves as a consultant or speaker for Acandis, Bayer Healthcare, Boehringer Ingelheim, BristolMyersSquibb/Pfizer, Covidien, and Glaxo Smith Kline; served as a lead investigator of the WAKE-UP study; was principal investigator of the THRILL study; and received grants from the European Union (grant No. 278276 and 634809) and Deutsche Forschungsgemeinschaft (SFB 936, Projekt C2). CG received fees as a consultant or lecture fees from Bayer Vital, Boehringer Ingelheim, EBS Technologies, Glaxo Smith Kline, Lundbeck, Pfizer, Sanofi Aventis, Silk Road Medical, and UCB. The other authors have no conflicts of interest.
Patient consent Not required.
Ethics approval The study was approved by the ethics committee of the Medical Association of the City of Hamburg.
Provenance and peer review Not commissioned; externally peer reviewed.
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