Possible reasons include differences by study because nearly all MRIs came from 1 trial or because DWI is much more sensitive in detecting even small areas of infarction within an ASPECTS region. NCCT ASPECTS 0 to 4 did not show EVT benefit but DWI MRI did. Differences in EVT treatment effect were seen with ASPECTS when baseline imaging was performed by magnetic resonance imaging (MRI) versus NCCT. 6Īn analysis of the centrally adjudicated NCCTs in the HERMES collaboration (Highly Effective Reperfusion Evaluated in Multiple Endovascular Stroke Trials) confirmed that among patients enrolled with low ASPECTS (off protocol), there is evidence of a treatment effect for EVT (shift toward less disability) in all ASPECTS subgroups except ASPECTS 0 to 2.
In a single-center consecutive case series that included a majority of patients receiving EVT, poor collateral status on multiphase computed tomographic angiogram (CTA) was the only independent predictor of malignant middle cerebral artery (MCA) infarction even adjusted for recanalization status. Low ASPECTS/large core may also occur early after symptom onset in the setting of poor/no collateral flow beyond the LVO (eg, fast progressors). ASPECTS decay (infarct growth) is a common phenomenon associated with patient transport 3, 4 and is a major cause of transferred patients not receiving thrombectomy even though they may still benefit from the higher level of care provided at comprehensive centers. 2 Low ASPECTS/large core is common, in part, because of decentralized systems of care requiring a drip-and-ship treatment paradigm, resulting in patients presenting late to thrombectomy facilities because of patient/system delays or long transport times. Low ASPECTS/large core is a strong predictor of a poor prognosis overall, as demonstrated in the noncontrast CT (NCCT) ASPECTS 0 to 4 population of MR CLEAN (Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands) 1 and in a 2-center prospective mechanical thrombectomy (MT) registry where a diffusion-weighted imaging (DWI) ASPECTS cutoff of ≤4 revealed that only 13% had good outcome and mortality was 45.7% despite reperfusion. Patients with large baseline ischemic core lesion (ASPECTS of 70 mL were largely excluded per protocol from enrollment in most recent RCTs. Low ASPECTS (Alberta Stroke Program Early CT Score)/large core large vessel occlusion (LVO) ischemic stroke was deemed the highest priority population for further clinical trials to demonstrate EVT benefit. Individual study questions are discussed in detail below with mention of funding and design considerations when possible.ĮVT Versus No EVT Trial for Low Alberta Stroke Program Early CT Score/Large Core Large Vessel Occlusion Population Each population was then prioritized as low, medium, and high (Table I in the online-only Data Supplement). Consensus was achieved to evaluate these populations and clinical management questions for several key elements such as the availability of these population and feasibility of participation, readiness of EVT, presence of community and individual equipoise, and trial type best suited. In terms of new required EVT trials, a number of unproven stroke populations and important clinical management questions were discussed. How do we prioritize which further EVT RCTs to do first? What is the best approach to funding these trials?Īre different designs more appropriate for industry versus NIH? What are the patient populations where more EVT randomized clinical trials (RCTs) are required?Īre there novel design/outcome considerations for each?
The workshop sought to answer a series of questions/addressing specific topics:
This report is based on expert opinion distilled from a workshop at the STAIR X meeting held on October 23 to 24, 2017.
One major goal of the STAIR X meeting was to develop consensus recommendations for how to design trials for extension of endovascular treatment (EVT) to additional populations to expand the indications for this treatment. The STAIR (Stroke Treatment Academic Industry Roundtable) meetings bring together academic physicians, industry representatives, and regulators biannually to discuss approaches to enhance the development of stroke therapies.