Background and Purpose: Endovascular strategies provide unique opportunity to correlate angiographic measures of collateral circulation at the time of endovascular therapy. We conducted systematic analyses of collaterals at conventional angiography on recanalization, reperfusion and the clinical outcomes in the endovascular treatment arm of the Interventional Management of Stroke (IMS) III Trial. Methods: Prospective evaluation of angiographic collaterals was conducted via central review of subjects treated with endovascular therapy in IMS III (n=331). Collateral grade prior to endovascular therapy was assessed with the ASITN/SIR scale, blinded to all other data. Statistical analyses investigated the association between collaterals with baseline clinical variables, angiographic measures of recanalization, reperfusion and clinical outcomes. Results: Adequate views of collateral circulation to the ischemic territory were available in 276/331 (83%) subjects. Collateral grade was strongly related to both recanalization of the occluded arterial segment (p=0.0016) and downstream reperfusion (p<0.0001). Multivariable analyses confirmed that robust angiographic collateral grade was a significant predictor of good clinical outcome (mRS≤2) at 90 days (p=0.0353), adjusted for age, history of diabetes, NIHSS strata, and ASPECTS. The relationship between collateral flow and clinical outcome may depend on the degree of reperfusion. Conclusions: More robust collateral grade was associated with better recanalization, reperfusion, and subsequent better clinical outcomes. These data, from the largest endovascular trial to date, suggest that collaterals are an important consideration in future trial design.

Background and Purpose-Thrombectomy, primarily with stent retrievers with or without adjunctive aspiration, provided clinical benefit across multiple prospective randomized trials. Whether this benefit is exclusive to stent retrievers is unclear. Methods-THERAPY (The Randomized, Concurrent Controlled Trial to Assess the Penumbra System's Safety and Effectiveness in the Treatment of Acute Stroke; NCT01429350) was an international, multicenter, prospective, randomized (1:1), open label, blinded end point evaluation, concurrent controlled clinical trial of aspiration thrombectomy after intravenous alteplase (IAT) administration compared with intravenous-alteplase alone in patients with large vessel ischemic stroke because of a thrombus length of ≥8 mm. The primary efficacy end point was the percent of patients achieving independence at 90 days (modified Rankin Scale score, 0-2; intention-to-treat analysis). The primary safety end point was the rate of severe adverse events (SAEs) by 90 days (as treated analysis). Patients were randomized 1:1 across 36 centers in 2 countries (United States and Germany). Results-Enrollment was halted after 108 (55 IAT and 53 intravenous) patients (of 692 planned) because of external evidence of the added benefit of endovascular therapy to intravenous-alteplase alone. Functional independence was achieved in 38% IAT and 30% intravenous intention-to-treat groups (P=0.52). Intention-to-treat ordinal modified Rankin Scale odds ratio was 1.76 (95% confidence interval, 0.86-3.59; P=0.12) in favor of IAT. Secondary efficacy analyses all demonstrated a consistent direction of effect toward benefit of IAT. No differences in symptomatic intracranial hemorrhage rates (9.3% IAT versus 9.7% intravenous, P=1.0) or 90-day mortality (IAT: 12% versus intravenous: 23.9%, P=0.18) were observed. Conclusions-THERAPY did not achieve its primary end point in this underpowered sample. Directions of effect for all prespecified outcomes were both internally and externally consistent toward benefit. It is possible that an alternate method of thrombectomy, primary aspiration, will benefit selected patients harboring large vessel occlusions. Further study on this topic is indicated. Clinical Trial Registration-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01429350.

Objective:The objectives of this study were to measure the global impact of the pandemic on the volumes for intravenous thrombolysis (IVT), IVT transfers, and stroke hospitalizations over 4 months at the height of the pandemic (March 1 to June 30, 2020) compared with two control 4-month periods.Methods:We conducted a cross-sectional, observational, retrospective study across 6 continents, 70 countries, and 457 stroke centers. Diagnoses were identified by their ICD-10 codes and/or classifications in stroke databases.Results:There were 91,373 stroke admissions in the 4 months immediately before compared to 80,894 admissions during the pandemic months, representing an 11.5% (95%CI, -11.7 to - 11.3, p<0.0001) decline. There were 13,334 IVT therapies in the 4 months preceding compared to 11,570 procedures during the pandemic, representing a 13.2% (95%CI, -13.8 to -12.7, p<0.0001) drop. Interfacility IVT transfers decreased from 1,337 to 1,178, or an 11.9% decrease (95%CI, -13.7 to -10.3, p=0.001). Recovery of stroke hospitalization volume (9.5%, 95%CI 9.2-9.8, p<0.0001) was noted over the two later (May, June) versus the two earlier (March, April) pandemic months. There was a 1.48% stroke rate across 119,967 COVID-19 hospitalizations. SARS-CoV-2 infection was noted in 3.3% (1,722/52,026) of all stroke admissions.Conclusions:The COVID-19 pandemic was associated with a global decline in the volume of stroke hospitalizations, IVT, and interfacility IVT transfers. Primary stroke centers and centers with higher COVID19 inpatient volumes experienced steeper declines. Recovery of stroke hospitalization was noted in the later pandemic months.

Background and Purpose-Rapid and safe recanalization of occluded intracranial arteries in acute ischemic stroke (AIS) is challenging. Newly available self-expanding intracranial atherosclerotic stents (SEIS), which can be deployed rapidly and safely, make acute stenting an option for treating AIS. We present the feasibility of this technique. Methods-A retrospective analysis evaluated procedural protocols and clinical response to treatment in patients with AIS treated with SEIS. Descriptive statistics are presented with initial and follow-up National Institutes of Health Stroke Scale and modified Rankin Score. Results-Nine patients with AIS underwent acute SEIS placement. There was successful deployment of the Neuroform (nϭ4) and Wingspan (nϭ4/5) stents in the M1/M2 (nϭ5) and M3 (nϭ1) middle cerebral artery segments, intracranial internal carotid artery (one of 2), and intracranial vertebrobasilar junction (one). The Merci clot retrieval system (Concentric Medical) has been studied in a series of trials and been shown to have a 54% rate of TIMI 2/3 recanalization rate. 8 Until recently, intracranial stenting was limited to off-label use of balloon-mounted stents designed for cardiac circulation. These stents are poor tools for treating intracranial disease because they are rigid, making navigation in the tortuous intracranial circulation difficult. 9 The recently available self-expanding intracranial stents (SEIS) allow acute stenting as an option in AIS that is refractory to conventional management. 10 -12 We present our experience in the feasibility of SEIS for the treatment of AIS. MethodsAfter obtaining Institutional Review Board approval, the neurointerventional database at Medical College of Wisconsin was reviewed from July 2005 to October 2007 and patients with AIS in whom stent-assisted recanalization was performed were identified. Patients or their legal representatives gave prior informed consent for chemical or mechanical thrombolysis, including clot retrieval devices, angioplasty, and/or stenting. SEIS was performed in AIS within 8 hours of symptom onset with a National Institutes of Health Stroke Scale score Ն10 and cranial CT imaging without ICH or clear early cerebral infarction more than or equal to one third of the vessel distribution with angiographic occlusion (length 14 mm) amenable to SEIS (at least 3-mm landing zone pre-and postclot).Modified Rankin Scores (mRS), ICH, mortality, and vessel recanalization data were collected. Recanalization was assessed by 2 of the authors (OOZ and BFF), who were unaware of the study design at the time of interpretation using the accepted TICI/TIMI grading systems. 13 InterventionAfter the clot was identified, a 2000-unit heparin intravenous bolus followed by a 450-unit/hr intravenous infusion was administered throughout the procedure (IMS-III protocol). Stent placement was attempted after standard AIS intervention failure (no recanalization after 1 hour of chemical thrombolysis; mean dose, 9 mg; range, 6 to 15 mg; one Merci device use; or Ն70% residual ste...