Background The time–benefit relationship of endovascular thrombectomy (EVT) according to the size of the core infarct has been incompletely explored in prior studies. We investigated whether established infarct core size on baseline imaging modifies the relationship between onset-to-reperfusion time (OTR) and functional outcomes in patients with acute ischemic stroke treated with EVT.
Methods We analyzed a database containing individual patient data pooled from three prospective Solitaire stent retriever studies. The inclusion criteria were treatment with a Solitaire device and achievement of substantial reperfusion (modified Thrombolysis in Cerebral Infarction 2b–3). Main analyses were performed in patients with baseline Alberta Stroke Program Early CT Scores (ASPECTSs) of 7–10.
Results Among the 305 patients (mean age 67±13 years, 58% women), the proportions of patients in different categories of pretreatment infarct extent were: small (ASPECTS 9–10) 52.0%, moderate (ASPECTS 7–8) 37.1%, and large (ASPECTS 0–6) 7.6%. The mean OTR was 297±95 min. At 3 months, 60.1% of the patients achieved a good outcome. For OTRs of 2–8 hours, the rates of good outcomes at all time points were higher with higher baseline ASPECTS but declined with similar steepness. Both baseline ASPECTS (OR 1.23 (95% CI 1.04 to 1.45)) and OTR (every 30 min delay, OR 0.80 (95% CI 0.73 to 0.88)) were independently associated with a good 3-month outcome. No interaction between OTR and baseline ASPECTS was observed.
Conclusions Although patients with higher baseline ASPECTS are more likely to have good clinical outcomes at all OTR intervals after 2 hours, this benefit consistently declines with time, even in patients with a small infarct core, reinforcing the need to treat all patients as quickly as possible.
- endovascular thrombectomy
- solitaire stent
- onset to reperfusion
- acute ischemic stroke
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Contributors Study concept and design: J-TK, JLS. Acquisition of data: MG, EIL, DL, RJ, VMP, JG, AB, JLS. Analysis and interpretation of data: J-TK, JLS. Drafting of the manuscript: J-TK, JLS. Critical revision of the manuscript for important intellectual content: J-TK, MG, EIL, DL, RJ, VMP, JG, AB, JLS. Statistical analysis: J-TK, JLS.
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 MG: served as a consultant to Medtronic for design and conduct of the SWIFT PRIME trial; has also received honoraria from Medtronic/Covidien for speaking and teaching engagements; and was also one of the Principal Investigators for the ESCAPE trial. The ESCAPE trial was partially funded by Covidien through an unrestricted research grant to the University of Calgary. EIL: serves as a scientific consultant to Medtronic; has shareholder/ownership interest with Intratech Medical and Blockade Medical; has received fees from Abbott for carotid training; and has served as an expert witness for Renders Medical/Legal opinion. DL: a consultant to Stryker (modest) and Covidien (modest) and employed by the University of California, which holds a patent on retriever devices for stroke. RJ is a consultant for Medtronic. VMP: is a consultant for Medtronic (PI for SWIFT PRIME trial), Stryker (SC for DAWN trial [DWI or CTP Assessment With Clinical Mismatch in the Triage of Wake-Up and Late Presenting Strokes Undergoing Neurointervention]), Penumbra (SC for PROMISE study), and BALT (proctorship of products unrelated to ischemic stroke) and receives research grant from Philips. JG: is a global PI of STAR and SWIFT DIRECT (Medtronic), Consultancy; CEC member of the PROMISE study (Penumbra), Consultancy; and receives SNSF grants for magnetic resonance imaging in stroke. AB: has been a consultant for Covidien and has a licensing agreement with GE. JLS is an employee of the University of California. The University of California Regents receive funding for JLS’s services as a scientific consultant regarding trial design and conduct to Medtronic/Covidien, Stryker, Neuravia, BrainsGate, Pfizer, Squibb, Boehringer Ingelheim (prevention only), ZZ Biotech, and St Jude Medical. JLS has served as an unpaid site investigator in multicenter trials run by Lundbeck for which the University of California Regents received payments on the basis of clinical trial contracts for the number of subjects enrolled. JLS serves as an unpaid consultant to Genentech advising on the design and conduct of the PRISMS trial; neither the University of California nor JLS received any payments for this voluntary service. The University of California has patent rights in retrieval devices for stroke.
Provenance and peer review Not commissioned; externally peer reviewed.
Patient consent for publication Not required.