Clot characteristics in mechanical thrombectomy: Interim analysis of the excellent registry

Introduction: Red blood cell (RBC) rich vs fibrin rich clots have different mechanical properties and greater knowledge about clot composition in the context of clinical, imaging, and procedural factors in mechanical thrombectomy (MT) may help with procedural optimization. The EXCELLENT Registry (NCT03685578) is a prospective, global, multi-center, observational registry of EmboTrap as the first line MT device for large vessel occlusion (LVO). We present an interim analysis of clot collected per pass in the registry. Methods: Five hundred thirty-three clot specimens from 376 subjects were collected by 20 sites and sent for analysis by independent Central Labs under standardized protocol. Analysis was interrupted by COVID-19, but the labs were fully operational as of June 2020 and on track to deliver results for 300 subjects in Q4. At the time of abstract submission, composition data for 234 clots from 163 subjects was available. All available data will be presented at the time of the conference. Results: Cardioembolic etiology (n=100) was associated with lower RBC (40.2 vs 47.2%) and higher fibrin content (31.7 vs 26.7%) compared to large artery disease (n=12). Hyperdense/vessel susceptibility sign (78+, 24-, per independent imaging core lab) corresponded to higher mean RBC content (44.4 vs 34.9%). Treatment with IV tPA (60+, 91-) had no clear impact on clot composition (42.3 vs 40.6% RBC;30.4 vs 30.0% fibrin). Notably, clots retrieved with the first 2 passes of were more RBC rich (42.1 vs 28.0%) and clots retrieved in higher passes had a higher average fibrin content (35.5 vs 29.6%) suggesting that higher fibrin content leads to greater refractoriness. Conclusions: Clot density/susceptibility on baseline imaging, stroke etiology and number ofthrombectomy passes were associated with differential clot composition. These findings may havepotential implications for the development of better MT strategies.

Stroke etiologies in patients with COVID-19: the svin COVID-19 multinational registry

Background and purpose: Coronavirus disease 2019 (COVID-19) is associated with a small but clinically significant risk of stroke, the cause of which is frequently cryptogenic. In a large multinational cohort of consecutive COVID-19 patients with stroke, we evaluated clinical predictors of cryptogenic stroke, short-term functional outcomes and in-hospital mortality among patients according to stroke etiology. Methods: We explored clinical characteristics and short-term outcomes of consecutively evaluated patients 18 years of age or older with acute ischemic stroke (AIS) and laboratory-confirmed COVID- 19 from 31 hospitals in 4 countries (3/1/20-6/16/20). Results: Of the 14.483 laboratory-confirmed patients with COVID-19, 156 (1.1%) were diagnosed with AIS. Sixty-one (39.4%) were female, 84 (67.2%) white, and 88 (61.5%) were between 60-79 years of age. The most frequently reported etiology of AIS was cryptogenic (55/129, 42.6%), which was associated with significantly higher white blood cell count, c-reactive protein, and D-dimer levels than non-cryptogenic AIS patients (p</=0.05 for all comparisons). In a multivariable backward stepwise regression model estimating the odds of in-hospital mortality, cryptogenic stroke mechanism was associated with a fivefold greater odds in-hospital mortality than strokes due to any other mechanism (adjusted OR 5.16, 95%CI 1.41-18.87, p=0.01). In that model, older age (aOR2.05 per decade, 95%CI 1.35-3.11, p<0.01) and higher baseline NIHSS (aOR 1.12, 95%CI 1.02-1.21, p=0.01) were also independently predictive of mortality. Conclusions: Our findings suggest that cryptogenic stroke among COVID-19 patients may berelated to more severe disease and carries a significant risk of early mortality.

Decline in mild stroke presentations and intravenous thrombolysis during the COVID-19 pandemic: the society of vascular and interventional neurology registry

Introduction: To evaluate overall ischemic stroke rates, specific subtypes, and clinical presentation during the COVID-19 pandemic in a multicenter observational study from eight states across US. Methods: We compared all ischemic strokes admitted between January 2019 and May 2020, grouped as;March-May 2020 (COVID-19 period), March-May 2019 (seasonal pre-COVID period) and November 2019-January 2020 (immediate pre-COVID-19 period). Primary outcome was stroke severity at admission measured by NIHSS stratified as mild (0-7), moderate (8-14), and severe (>14) symptoms. Secondary outcomes were number of large vessel occlusions (LVOs), stroke etiology, IV-tPA rates, and disposition. Results: Of the 7,969 patients diagnosed with acute stroke during the study period, 933 (12%) presented in the COVID-19 period, 1319 (17%), and 1254 (16%) presented in the seasonal pre- COVID-19 and immediate pre-COVID-19 periods, respectively. Significant decline was observed in the weekly mean volume of newly diagnosed strokes (98±7.3 vs 50±20, p<0.01 and 95±10.5 vs 50±20, p<0.01), LVOs (16.5±3.8 vs 8.3±5.9, p<0.01 and 14.3± 4.5 vs 8.3±5.9, p<0.01), and IV-tPA (5.3±2.9 vs 10.9±3.4 and 12.7±4.1, p<0.01). Mean weekly proportion of LVOs remained the same, when compared with seasonal pre-COVID-19 period (18%±5 vs 16%±7, p=0.24) and immediate pre-COVID-19 period (17.4%±4 vs. 16%±7, p=0.32). Additionally, these patients presented with less severe disease (NIHSS<14;aOR: 0.63, 95%CI: 0.41-0.97, p=0.035) during the COVID-19 period ascompared to immediate pre-COVID-19 period. Conclusions: We observed a decrease in newly diagnosed stroke cases and rates of IV-tPAadministration, while the LVO frequency remained unchanged during the COVID-19 pandemic.Additionally, these stroke patients had more severe presentations.

Cerebrovascular events and outcomes in hospitalized patients with COVID-19: the society of vascular and interventional neurology multinational registry

Background: Severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) has been associated with a significant risk of thrombotic events in critically ill patients. Aims: To summarize the findings of a multinational observational cohort of patients with SARS-CoV- 2 and cerebrovascular disease. Methods: Retrospective observational cohort of consecutive adults evaluated in the emergency department and/or admitted with coronavirus disease 2019 (COVID-19) across 31 hospitals in 4 countries (2/1/2020 - 06/16/2020). The primary outcome was the incidence rate of cerebrovascular events, inclusive of acute ischemic stroke, intracranial hemorrhages (ICH), and cortical vein and/or sinus thrombosis (CVST). Results: Of the 14,483 patients with laboratory-confirmed SARS-CoV-2, 172 were diagnosed with an acute cerebrovascular event (1.13% of cohort;1130/100,000 patients, 95%CI 970- 1320/100,000), 68/171 (40.5%) of whom were female and 96/172 (55.8%) were between the ages 60-79 years. Of these, 156 had acute ischemic stroke (1.08%;1080/100,000 95%CI 920- 1260/100,000), 28 ICH (0.19%;190/100,000 95%CI 130 - 280/100,000) and 3 with CVST (0.02%;20/100,000, 95%CI 4-60/100,000). The in-hospital mortality rate for SARS-CoV-2-associated stroke was 38.1% and for ICH 58.3%. After adjusting for clustering by site and age, baseline strokeseverity, and all predictors of in-hospital mortality found in univariate regression (p<0.1: male sex,tobacco use, arrival by emergency medical services, lower platelet and lymphocyte counts, andintracranial occlusion), cryptogenic stroke mechanism (aOR 5.01, 95%CI 1.63-15.44, p<0.01), olderage (aOR 1.78, 95%CI 1.07-2.94, p=0.03), and lower lymphocyte count on admission (aOR 0.58,95%CI 0.34-0.98 p=0.04) were the only independent predictors of mortality among patients withstroke and COVID-19. Conclusions: COVID-19 is associated with a small but significant risk of clinically relevantcerebrovascular events, particularly ischemic stroke. The mortality rate is high for COVID-19associated cerebrovascular complications, therefore aggressive monitoring and early interventionshould be pursued to mitigate poor outcomes.

Acute stroke care during the COVID-19 pandemic: the society of vascular and interventional neurology collaboration

Background: We sought to evaluate whether the coronavirus disease 2019 (COVID-19) pandemic may have contributed to delays in acute stroke management at Comprehensive Stroke Centers (CSCs). Methods: Pooled clinical data of consecutive adult stroke patients from 12 U.S. CSCs (1/1/2019- 5/31/2020) were queried. The rate of thrombolysis for non-transferred patients within the Target: Stroke goal of 60min was compared between patients admitted 3/1/2019-5/31/2019 (pre-COVID-19) and 3/1/2020-5/31/2020 (COVID-19). The time from arrival to imaging and treatment with thrombolysis or thrombectomy, as continuous variables, were also assessed. Results: Of the 7906 patients included, 1319 were admitted pre-COVID-19 and 933 were admitted during COVID-19, 15% of whom underwent intravenous thrombolysis. There was no difference in the rate of thrombolysis within 60min during COVID-19 (OR 0.88, 95%CI 0.42-1.86, p=0.74), despite adjustment for variables associated with earlier treatment (adjusted OR 0.82, 95%CI 0.38-1.76, p=0.61). There was no significant overall delay to thrombolysis during the COVID-19 period vs. pe- COVID-19 (p=0.42), even after multivariable adjustment (p=0.63) or after comparison across months leading to COVID-19 (Figure). The only independent predictor of delayed treatment time between periods was the use of emergency medical services (adjusted β=-6.93, 95%CI -12.83 -1.04, p=0.03). There was no significant delay from hospital arrival to imaging in all patients, or imaging to skin puncture in patients who underwent thrombectomy. Conclusions: There was no independent effect of the COVID-19 period on delays in acute care with respect to thrombolysis or thrombectomy in this multicenter observational cohort. Further studies are warranted to externally validate these findings, and determine if site volume or center accreditation may mediate a collateral effect of the pandemic on stroke care paradigms.

COVID-19 Era Stroke Service: Virtually Normal. LID - 39

Objective: To characterize my experience in the inpatient stroke service in an amusing fashion. Background: The COVID-19 pandemic broke out during my time as a stroke fellow. It was a unique experience. Methods: A non-exhaustive review of my memories as a stroke fellow during the COVID-19 pandemic was performed. I sat down and wrote the article. Then, I illustrated the figure. Results: All results are not statistically significant unless otherwise noted. Conclusions: Zoom conferences are a promising technology for stroke services. Further studies are needed to further elucidate their benefits and drawbacks. FAU - Liaw, Nicholas