The Management of Persistent Distal Occlusions after Mechanical Thrombectomy and Thrombolysis: An Inter- and Intrarater Agreement Study

BACKGROUND AND PURPOSE

The best management of patients with persistent distal occlusion after mechanical thrombectomy with or without IV thrombolysis remains unknown. We sought to evaluate the variability and agreement in decision-making for persistent distal occlusions.

MATERIALS AND METHODS

A portfolio of 60 cases was sent to clinicians with varying backgrounds and experience. Responders were asked whether they considered conservative management or rescue therapy (stent retriever, aspiration, or intra-arterial thrombolytics) a treatment option as well as their willingness to enroll patients in a randomized trial. Agreement was assessed using κ statistics.

RESULTS

The electronic survey was answered by 31 physicians (8 vascular neurologists and 23 interventional neuroradiologists). Decisions for rescue therapies were more frequent (n = 1116/1860, 60%) than for conservative management (n = 744/1860, 40%; P < .001). Interrater agreement regarding the final management decision was "slight" (κ = 0.12; 95% CI, 0.09-0.14) and did not improve when subgroups of clinicians were studied according to background, experience, and specialty or when cases were grouped according to the level of occlusion. On delayed re-questioning, 23 of 29 respondents (79.3%) disagreed with themselves on at least 20% of cases. Respondents were willing to offer trial participation in 1295 of 1860 (69.6%) cases.

CONCLUSIONS

Individuals did not agree regarding the best management of patients with persistent distal occlusion after mechanical thrombectomy and IV thrombolysis. There is sufficient uncertainty to justify a dedicated randomized trial.

Characteristics of Ischemic Stroke Despite Oral Anticoagulant Use For Atrial Fibrillation

Oral anticoagulation (OAC) prevents stroke in atrial fibrillation, yet a residual stroke risk remains. In this single-center retrospective analysis of acute ischemic stroke patients despite OAC, suboptimal OAC treatment is common (30%: inappropriate dosing (17%); patient non-adherence (13%)). Other causes of stroke included OAC interruption (14.5%), a competing stroke mechanism (11.0%), and undetermined breakthrough stroke in 44.5%. Overall, easily modifiable causes of ischemic stroke despite OAC are common. Accordingly, strategies to improve treatment compliance, including appropriate dosing along with guideline-based risk factor and periprocedural OAC management, should be emphasized to improve secondary stroke prevention in this patient population.

Successful Reperfusion is Associated with Favorable Functional Outcome despite Vessel Perforation during Thrombectomy: A Case Series and Systematic Review

BACKGROUND

Arterial perforation is a potentially serious complication during endovascular thrombectomy.

PURPOSE

Our aim was to describe interventional approaches after arterial perforation during endovascular thrombectomy and to determine whether reperfusion remains associated with favorable outcome despite this complication.

DATA SOURCES

Data from consecutive patients with acute stroke undergoing endovascular thrombectomy were retrospectively collected between 2015 to 2020 from a single-center cohort, and a systematic review was performed using PubMed, EMBASE, and Ovid MEDLINE up to June 2020.

STUDY SELECTION

Articles reporting functional outcome after arterial perforation during endovascular thrombectomy were selected.

DATA ANALYSIS

Functional outcomes of patients achieving successful reperfusion (TICI 2b/3) were compared with outcomes of those with unsuccessful reperfusion in our single-center cohort. We then summarized the literature review to describe interventional approaches and outcomes after arterial perforation during endovascular thrombectomy.

DATA SYNTHESIS

In our single-center cohort, 1419 patients underwent endovascular thrombectomy, among whom 32 (2.3%) had vessel perforation and were included in the analysis. The most common hemostatic strategy was watchful waiting (71% of cases). Patients with successful reperfusion had a higher proportion of favorable 90-day mRS scores (60% versus 12.5%; P = .006) and a lower mortality rate (13.3% versus 56.3%, P = .01) than patients without successful reperfusion. Thirteen articles were included in the systematic review. Successful reperfusion also appeared to be associated with better outcomes.

LIMITATIONS

Given the low number of published reports, we performed only a descriptive analysis.

CONCLUSIONS

Arterial perforation during endovascular thrombectomy is rare but is associated with high mortality rates and poor outcome. However, successful reperfusion remains correlated with favorable outcome in these patients.

Non-contrast CT markers of intracerebral hematoma expansion: a reliability study

OBJECTIVES

We evaluated whether clinicians agree in the detection of non-contrast CT markers of intracerebral hemorrhage (ICH) expansion.

METHODS

From our local dataset, we randomly sampled 60 patients diagnosed with spontaneous ICH. Fifteen physicians and trainees (Stroke Neurology, Interventional and Diagnostic Neuroradiology) were trained to identify six density (Barras density, black hole, blend, hypodensity, fluid level, swirl) and three shape (Barras shape, island, satellite) expansion markers, using standardized definitions. Thirteen raters performed a second assessment. Inter- and intra-rater agreement were measured using Gwet's AC₁, with a coefficient > 0.60 indicating substantial to almost perfect agreement.

RESULTS

Almost perfect inter-rater agreement was observed for the swirl (0.85, 95% CI: 0.78-0.90) and fluid level (0.84, 95% CI: 0.76-0.90) markers, while the hypodensity (0.67, 95% CI: 0.56-0.76) and blend (0.62, 95% CI: 0.51-0.71) markers showed substantial agreement. Inter-rater agreement was otherwise moderate, and comparable between density and shape markers. Inter-rater agreement was lower for the three markers that require the rater to identify one specific axial slice (Barras density, Barras shape, island: 0.46, 95% CI: 0.40-0.52 versus others: 0.60, 95% CI: 0.56-0.63). Inter-observer agreement did not differ when stratified for raters' experience, hematoma location, volume, or anticoagulation status. Intra-rater agreement was substantial to almost perfect for all but the black hole marker.

CONCLUSION

In a large sample of raters with different backgrounds and expertise levels, only four of nine non-contrast CT markers of ICH expansion showed substantial to almost perfect inter-rater agreement.

KEY POINTS

• In a sample of 15 raters and 60 patients, only four of nine non-contrast CT markers of ICH expansion showed substantial to almost perfect inter-rater agreement (Gwet's AC₁> 0.60). • Intra-rater agreement was substantial to almost perfect for eight of nine hematoma expansion markers. • Only the blend, fluid level, and swirl markers achieved substantial to almost perfect agreement across all three measures of reliability (inter-rater agreement, intra-rater agreement, agreement with the results of a reference reading).

Three-month functional outcomes following endovascular thrombectomy during the first wave of the COVID-19 pandemic: a Canadian single-center cohort study

BACKGROUND

The COVID-19 pandemic has disrupted acute stroke care logistics, including delays in hyperacute management and decreased monitoring following endovascular therapy (EVT). We aimed to assess the impact of the pandemic on 90-day functional outcome among patients treated with EVT.

METHODS

This is an observational cohort study including all patients evaluated for an acute stroke between March 30, 2020 and September 30, 2020 (pandemic cohort) and 2019 (reference cohort) in a high-volume Canadian academic stroke center. We collected baseline characteristics, acute reperfusion treatment and management metrics. For EVT-treated patients, we assessed the modified Rankin score (mRS) at 90 days. We evaluated the impact of the pandemic on a 90-day favourable functional status (defined as mRS 0-2) and death using multivariable logistic regressions.

RESULTS

Among 383 and 339 patients included in the pandemic and reference cohorts, baseline characteristics were similar. Delays from symptom onset to evaluation and in-house treatment were longer during the early first wave, but returned to reference values in the subsequent months. Among the 127 and 136 EVT-treated patients in each respective cohort, favourable 90-day outcome occurred in 53/99 (53%) vs 52/109 (48%, p=0.40), whereas 22/99 (22%) and 28/109 (26%, p=0.56) patients died. In multivariable regressions, the pandemic period was not associated with 90-day favourable functional status (aOR 1.27, 95% CI 0.60 to 2.56) or death (aOR 0.74, 95% CI 0.33 to 1.63).

CONCLUSION

In this single-center cohort study conducted in a Canadian pandemic epicenter, the first 6 months of the COVID-19 pandemic did not impact 90-day functional outcomes or death among EVT-treated patients.

Noninvasive Angiographic Results of Clipped or Coiled Intracranial Aneurysms: An Inter- and Intraobserver Reliability Study

BACKGROUND AND PURPOSE

Noninvasive angiography is commonly used to assess the outcome of surgical or endovascular treatment of intracranial aneurysms in clinical series or randomized trials. We sought to assess whether a standardized 3-grade classification system could be reliably used to compare the CTA and MRA results of both treatments.

MATERIALS AND METHODS

An electronic portfolio composed of CTAs of 30 clipped and MRAs of 30 coiled aneurysms was independently evaluated by 24 raters of diverse experience and training backgrounds. Twenty raters performed a second evaluation 1 month later. Raters were asked which angiographic grade and management decision (retreatment; close or long-term follow-up) would be most appropriate for each case. Agreement was analyzed using the Krippendorff α (α_K) statistic, and the relationship between angiographic grade and clinical management choice, using the Fisher exact and Cramer V tests.

RESULTS

Interrater agreement was substantial (α_K = 0.63; 95% CI, 0.55-0.70); results were slightly better for MRA results of coiling (α_K = 0.69; 95% CI, 0.56-0.76) than for CTA results of clipping (α_K = 0.58; 95% CI, 0.44-0.69). Intrarater agreement was substantial to almost perfect. Interrater agreement regarding clinical management was moderate for both clipped (α_K = 0.49; 95% CI, 0.32-0.61) and coiled subgroups (α_K = 0.47; 95% CI, 0.34-0.54). The choice of clinical management was strongly associated with the size of the residuum (mean Cramer V = 0.77 [SD, 0.14]), but complete occlusions (grade 1) were followed more closely after coiling than after clipping (P = .01).

CONCLUSIONS

A standardized 3-grade scale was found to be a reliable and clinically meaningful tool to compare the results of clipping and coiling of aneurysms using CTA or MRA.

Prospective Evaluation of a Two-Scale Protocol for Prehospital Large Vessel Occlusion Detection

Background and purposes: Stroke severity scales may expedite prehospital large vessel occlusion (LVO) stroke detection, but few are validated for paramedic use. We evaluated the feasibility of introducing the Cincinnati Stroke Triage Assessment Tool (C-STAT) in the field and its capacity to detect LVO stroke.Methods: We performed a prospective paramedic-based study assessing C-STAT in the field on patients currently redirected to two comprehensive stroke centers (CSC), based on a Cincinnati Prehospital Stroke Scale (CPSS) score of 3/3. C-STAT was administered by on-site paramedics with telephone guidance from trained centralized clinical support paramedics.Results: Between October 2018 and November 2019, C-STAT scores were obtained in 188/218 (86.2%) patients, among which 118/188 (62.8%) were positive. Paramedics reported performing the C-STAT in less than 5 minutes on 170/188 (90.4%) patients and noted no difficulties administering the scale in 151/188 (80.3%). A positive C-STAT identified 51/68 (75%) LVO strokes in the cohort, demonstrating a 43% (95% CI: 38%-48%) positive and 76% (95% CI: 66%-83%) negative predictive value for LVO stroke diagnosis. In a cohort of 100 patients with CPSS 3/3, requiring a positive C-STAT for redirection would decrease CSC patient volume by 37 but miss 9 of 36 LVO strokes.Conclusion: Prehospital administration of the C-STAT was feasible, using a model of minimal paramedic training and real-time telephone guidance. A protocol based on both a CPSS 3/3 and a positive C-STAT would decrease CSC redirected patient volume by one-third but would miss one-quarter of LVO strokes when compared to a CPSS-based protocol.

Abstract P258: The COVID-19 Pandemic is Not Associated With Worse 90-Day Functional Outcomes Following Endovascular Thrombectomy Despite Increased Delays to Recanalization

Introduction: Several comprehensive stroke centers (CSC) have reported increased delays to reperfusion in acute stroke during the COVID-19 pandemic, but it is unknown whether the pandemic is associated with worse functional outcomes in EVT-treated patients.

Methods: We performed an observational cohort study of consecutive adult patients evaluated for suspected stroke at our CSC (located in Montreal, a Canadian pandemic epicenter) between March 30 and May 15 2020 (prospective pandemic cohort) and 2019 (retrospective non-pandemic cohort). We excluded in-hospital strokes. We compared short-term (in-house door-to-puncture and door-to-recanalization delays, TICI 2b/3, complications during EVT) and long-term (90-day mRS ≤2 and death) outcomes with univariate analyses. We assessed the effect of the pandemic on 90-day mRS while controlling for clinical confounders.

Results: Overall, 111 and 106 patients were included in the pandemic and non-pandemic cohorts, respectively. The prevalence of COVID-19 in the pandemic cohort was 3% (3/104). Among ischemic stroke patients, 31/77 (40%) and 41/71 (58%) underwent EVT in each respective cohort (p=0.03). Among EVT-treated patients, baseline characteristics and NIHSS scores were similar (median [interquartile range]: 20 [12-25] vs 18 [14-20], p=0.18), but pre-stroke mRS was lower in the exposed cohort (0 [0-1] vs 1 [0-2], p=0.04). Door-to-puncture (87 [65-102] vs 56 [47-74] min, p=0.07) metrics were similar, but door-to-recanalization (122 [99-126] vs 89 [67-97] min, p<0.01) metrics were longer during the pandemic. The proportions of patients with TICI 2b/3 (94 vs 85%, p=0.27) and with complications during EVT (23 vs 22%, p=0.95) were similar, as were those for 90-day mRS ≤2 (42 vs 37%, p=0.64) and death (19 vs 20%, p=0.99). The logistic multivariate regression did not disclose an association between the COVID-19 pandemic and 90-day mRS ≤2 (aOR 0.70, 95% CI 0.06-7.95).

Conclusion: The COVID-19 pandemic does not appear to have a negative impact on 90-day functional status among EVT-treated patients despite increased delays to recanalization. However, patient selection may have been stricter during the pandemic, as a smaller proportion of evaluated patients underwent EVT and those treated had lower pre-stroke mRS.

Streamlined Poststroke Treatment Order Sets During the SARS-CoV-2 Pandemic: Simplifying While Not Compromising Care

BACKGROUND AND PURPOSE

Standard poststroke treatment monitoring protocols are made problematic during the coronavirus disease 2019 (COVID-19) pandemic by the frequency of patient assessments, requiring repeated donning and doffing procedures in a short interval of time.

METHODS

A streamlined poststroke treatment protocol was developed to limit frequency of patient encounters while maximizing the yield of each encounter by grouping together different components of poststroke care into single bedside visits.

RESULTS

Streamlined order sets were developed late March 2020. During the first 6 weeks following implementation, 70 patients were admitted to a geographically defined designated warm COVID-19 unit with modified poststroke care order sets. Of these, 33 (47.1%) patients received acute reperfusion therapy. All but 3 patients evolved favorably with either stable or improving National Institutes of Health Stroke Scale at 24 hours. In the 3 patients who experienced early neurological deterioration, none were found to be attributable to insufficient patient monitoring.

CONCLUSIONS

Adapting preexisting poststroke care protocols may be necessary while the risk of COVID-19 infection remains high. We propose a streamlined approach to facilitate poststroke monitoring in patients with stroke with unknown COVID status.

Acute carotid stenting in patients undergoing thrombectomy: a systematic review and meta-analysis

BACKGROUND

The benefit of acute carotid stenting compared with no acute stenting on clinical outcomes among patients with tandem lesions (TL) undergoing endovascular thrombectomy (EVT) remains unknown.

METHODS

We conducted a a systematic review and meta-analysis of studies comparing acute carotid stenting versus no stenting among TL patients undergoing EVT with regards to 90 day modified Rankin Scale (mRS) score, symptomatic intracerebral hemorrhage (sICH), and mortality. Four reviewers screened citations for eligibility and two assessed retained studies for risk of bias and data extraction. A random effects model was used for the synthesis of aggregated data.

RESULTS

21 studies (n=1635 patients) were identified for the systematic review; 19 were cohort studies, 1 was a post-hoc analysis of an EVT trial, and 1 was a pilot randomized controlled trial. 16 studies were included in the meta-analysis. Acute stenting was associated with a favorable 90 day mRS score: OR 1.43 (95% CI 1.07, 1.91). No significant heterogeneity between studies was found for this outcome (I²=17.0%; χ²=18.07, p=0.26). There were no statistically significant differences for 3 month mortality (OR 0.80 (95% CI 0.50, 1.28)) or sICH (OR 1.41 (95% CI 0.91, 2.19)).

CONCLUSIONS

This meta-analysis suggests that among TL patients undergoing EVT, acute carotid stenting is associated with a greater likelihood of favorable outcome at 90 days compared with no stenting.

Tandem Carotid Lesions in Acute Ischemic Stroke: Mechanisms, Therapeutic Challenges, and Future Directions

Approximately 15% of patients undergoing endovascular thrombectomy for anterior circulation acute ischemic stroke have a tandem lesion, defined as a severe stenosis or occlusion of the cervical internal carotid artery ipsilateral to its intracranial occlusion. Patients with tandem lesions have worse outcomes than patients with isolated intracranial occlusions, but the optimal management of their carotid lesions during endovascular thrombectomy remains controversial. The main options commonly used in current practice include acute stent placement in the carotid lesion versus thrombectomy alone without definitive revascularization of the carotid artery. While treatment decisions for these patients are often complex and strategies vary according to clinical, anatomic, and technical considerations, only results from randomized trials comparing these approaches are likely to strengthen current recommendations and optimize patient care.

Exophthalmos following mechanical thrombectomy for anterior circulation stroke: A retrospective study and review of literature

BACKGROUND

Anecdotal cases of exophthalmos after acute mechanical thrombectomy have been described. We sought to estimate the incidence in a large cohort of patients with acute anterior circulation stroke treated with mechanical thrombectomy. Secondarily, we aimed to evaluate the underlying mechanism and to differentiate it on imaging from other pathology with similar clinical orbital features.

METHODS

Between November 2016 and November 2018, we performed a retrospective single-center study of 250 patients who underwent anterior circulation mechanical thrombectomy. Development of exophthalmos was independently evaluated by two readers on preprocedure and 24-h postprocedure non-contrast cerebral CT.

RESULTS

In the mechanical thrombectomy cohort, six individuals (2.4%) developed interval ipsilateral exophthalmos at 24 h. Of these, at least two patients developed clinical symptoms. There was almost perfect agreement between assessments of the two readers (Cohen's kappa = 0.907 (95% confidence interval: 0.726, 1.000)). In two patients, there was delayed ophthalmic artery filling on digital subtraction angiography. None of the patients had features of a direct carotid-cavernous fistula.

CONCLUSIONS

Exophthalmos is not uncommon after mechanical thrombectomy (2.4%). The underlying mechanism is difficult to confirm, but it is most likely due to orbital ischemia from hypoperfusion or distal emboli.

Abstract WMP9: Real-World Outcomes of Patients Presenting with Acute Ischemic Stroke >6 Hours Since Symptom Onset Treated With Endovascular Therapy

Introduction: Endovascular therapy(EVT) is proven effective for patients with acute ischemic stroke with proximal vessel occlusion, treated within 6 hours since symptom onset. However, up to 30% of stroke patients wake up with their symptoms (“wake-up stroke” (WUS)) or have an unknown time of onset. Canadian guidelines suggest that EVT may also be effective up to 12 hours after onset and yet-to-be published data from the DAWN trial also suggest a strong benefit of EVT for these patients if selected by perfusion imaging. We aimed to examine the real-world effectiveness of EVT in late-presenting stroke patients selected for EVT with a simple non-contrast CT (NCCT) and simple phase CT angiogram (CTA).

Methods: We analyzed a prospectively collected registry of epidemiological, clinical and imaging data of patients treated for acute ischemic stroke ≥6 hours since symptom onset or WUS in a tertiary stroke center (Hôpital Notre-Dame, Montréal) between 2016 and 2017. Eligibility for EVT was based on a combination of disabling neurological deficit, a NCCT with salvageable brain tissue (ASPECTS >5), and presence of a LVO on CTA.

Results: Over a 16-month period, a total of 366 patients were treated with IV thrombolysis and/or EVT. Of these, 46 had WUS or presented ≥ 6 hours since symptom onset and received EVT. Median age was 70, median baseline mRS score 1, median NIHSS at arrival 17 and median ASPECTS 9. Good collaterals on CTA were noted in 63%(29) of patients. 5 patients had posterior circulation stroke with basilar occlusion. Median time from last time seen normal to admission was 9h17(IQR, 6h44-12h46). 31 (67.4%) NCCTs were done at a referent center and not repeated locally to avoid treatment delays. At 3-month follow-up, functional autonomy(mRS ≤ 2) was found in 15 (32.6%) patients while 15 (32,6%) died (mRS=6). Symptomatic hemorrhagic transformation occurred in 3(6.5%) patients.

Conclusions: In a real-world setting, EVT is feasible in late-presenting stroke patients selected by NCCT and yields favorable outcomes similar to those seen in the more pragmatic EVT trials.

The cost of materials for intra-arterial thrombectomy

This paper reports the cost of endovascular materials used for the treatment of large-vessel ischemic stroke in the anterior circulation according to the angiographic score and clinical results at three months. From November 2009 to July 2011, 57 ischemic patients (mean age, 64.6 ±13.8 years) with anterior large vessel occlusion were included. Mean National Institutes of Health Stroke Scale (NIHSS) on admission was 18.4 ± 4.9. Mean duration of symptoms until the arterial puncture was 207±67 minutes. Recanalization was assessed using the Thrombolysis In Myocardial Infarction (TIMI) score. Patient selection was performed on a non-enhanced CT scanner. According to the TIMI final angiographic score and the modified Rankin score (mRS) at three months, we determined the cost of the material used. Complete (n=12, TIMI grade 3) or partial perfusion (n=35, TIMI grade 2) was achieved in 47 (82.5%) lesions. At three months, 33.3% (n=19) had a mRS score ≤ 2. The mean cost of the material used in the operative room was 5018±2402 euro. Intra-arterial thrombolysis presents a substantial initial cost and the long-term economic impact has to be evaluated. Our health system has to take the price of these new technologies into account for future medical choices and urgently evaluate them in randomized controlled trials.