PRERISK: A Personalized, Artificial Intelligence-Based and Statistically-Based Stroke Recurrence Predictor for Recurrent Stroke

BACKGROUND

Predicting stroke recurrence for individual patients is difficult, but individualized prediction may improve stroke survivors' engagement in self-care. We developed PRERISK: a statistical and machine learning classifier to predict individual risk of stroke recurrence.

METHODS

We analyzed clinical and socioeconomic data from a prospectively collected public health care-based data set of 41 975 patients admitted with stroke diagnosis in 88 public health centers over 6 years (2014-2020) in Catalonia-Spain. A new stroke diagnosis at least 24 hours after the index event was considered as a recurrent stroke, which was considered as our outcome of interest. We trained several supervised machine learning models to provide individualized risk over time and compared them with a Cox regression model. Models were trained to predict early, late, and long-term recurrence risk, within 90, 91 to 365, and >365 days, respectively. C statistics and area under the receiver operating characteristic curve were used to assess the accuracy of the models.

RESULTS

Overall, 16.21% (5932 of 36 114) of patients had stroke recurrence during a median follow-up of 2.69 years. The most powerful predictors of stroke recurrence were time from previous stroke, Barthel Index, atrial fibrillation, dyslipidemia, age, diabetes, and sex, which were used to create a simplified model with similar performance, together with modifiable vascular risk factors (glycemia, body mass index, high blood pressure, cholesterol, tobacco dependence, and alcohol abuse). The areas under the receiver operating characteristic curve were 0.76 (95% CI, 0.74-0.77), 0.60 (95% CI, 0.58-0.61), and 0.71 (95% CI, 0.69-0.72) for early, late, and long-term recurrence risk, respectively. The areas under the receiver operating characteristic curve of the Cox risk class probability were 0.73 (95% CI, 0.72-0.75), 0.59 (95% CI, 0.57-0.61), and 0.67 (95% CI, 0.66-0.70); machine learning approaches (random forest and AdaBoost) showed statistically significant improvement (P<0.05) over the Cox model for the 3 recurrence time periods. Stroke recurrence curves can be simulated for each patient under different degrees of control of modifiable factors.

CONCLUSIONS

PRERISK is a novel approach that provides a personalized and fairly accurate risk prediction of stroke recurrence over time. The model has the potential to incorporate dynamic control of risk factors.

Enhancing blood pressure management protocol implementation in patients with acute intracerebral haemorrhage through a nursing-led approach: A retrospective cohort study

AIM

To evaluate the impact of nurse care changes in implementing a blood pressure management protocol on achieving rapid, intensive and sustained blood pressure reduction in acute intracerebral haemorrhage patients.

DESIGN

Retrospective cohort study of prospectively collected data over 6 years.

METHODS

Intracerebral haemorrhage patients within 6 h and systolic blood pressure ≥ 150 mmHg followed a rapid (starting treatment at computed tomography suite with a target achievement goal of ≤60 min), intensive (target systolic blood pressure < 140 mmHg) and sustained (maintaining target stability for 24 h) blood pressure management plan. We differentiated six periods: P1, stroke nurse at computed tomography suite (baseline period); P2, antihypertensive titration by stroke nurse; P3, retraining by neurologists; P4, integration of a stroke advanced practice nurse; P5, after COVID-19 impact; and P6, retraining by stroke advanced practice nurse. Outcomes included first-hour target achievement (primary outcome), tomography-to-treatment and treatment-to-target times, first-hour maximum dose of antihypertensive treatment and 6-h and 24-h systolic blood pressure variability.

RESULTS

Compared to P1, antihypertensive titration by stroke nurses (P2) reduced treatment-to-target time and increased the rate of first-hour target achievement, retraining of stroke nurses by neurologists (P3) maintained a higher rate of first-hour target achievement and the integration of a stroke advanced practice nurse (P4) reduced both 6-h and 24-h systolic blood pressure variability. However, 6-h systolic blood pressure variability increased from P4 to P5 following the impact of the COVID-19 pandemic. Finally, compared to P1, retraining of stroke nurses by stroke advanced practice nurse (P6) reduced tomography-to-treatment time and increased the first-hour maximum dose of antihypertensive treatment.

CONCLUSION

Changes in nursing care and continuous education can significantly enhance the time metrics and blood pressure outcomes in acute intracerebral haemorrhage patients.

REPORTING METHOD

STROBE guidelines.

PATIENT AND PUBLIC CONTRIBUTION

No Patient or Public Contribution.

Acute management of cerebral venous thrombosis: Indications, technique, and outcome of endovascular treatment in two high-volume centers

INTRODUCTION

After several uncontrolled studies and one randomized clinical trial, there is still uncertainty regarding the role of endovascular treatment (EVT) in cerebral venous thrombosis (CVT). This study aims to describe and assess different acute management strategies in the treatment of CVT.

METHODS

We performed a retrospective analysis of an international two-center registry of CVT patients admitted since 2019. Good outcome was defined as a return to baseline modified Rankin scale at three months. We described and compared EVT versus no-EVT patients.

RESULTS

We included 61 patients. Only one did not receive systemic anticoagulation. EVT was performed in 13/61 (20%) of the cases, with a median time from diagnosis to puncture of 4.5 h (1.25-28.5). EVT patients had a higher median baseline NIHSS [6 (IQR 2-17) vs 0 (0-2.7), p = 0.002)] and a higher incidence of intracerebral hemorrhage (53.8% vs 20.3%, p = 0.03). Recanalization was achieved in 10/13 (77%) patients. Thrombectomy was performed in every case with angioplasty in 7 out of 12 patients and stenting in 3 cases. No postprocedural complication was reported. An improvement of the median NIHSS from baseline to discharge [6 (2-17) vs 1(0-3.75); p < 0.001] was observed in EVT group. A total of 31/60 patients (50.8%) had good outcomes. Adjusting to NIHSS and ICH, EVT had a non-significant increase in the odds of a good outcome [aOR 1.42 (95%CI 0.73-2.8, p = 0.307)].

CONCLUSIONS

EVT in combination with anticoagulation was safe in acute treatment of CVT as suggested by NIHSS improvement. Selected patients may benefit from this treatment.

Clinico-radiological features of intracranial atherosclerosis-related large vessel occlusion prior to endovascular treatment

The identification of large vessel occlusion with underlying intracranial atherosclerotic disease (ICAS-LVO) before endovascular treatment (EVT) continues to be a challenge. We aimed to analyze baseline clinical-radiological features associated with ICAS-LVO that could lead to a prompt identification. We performed a retrospective cross-sectional study of consecutive patients with stroke treated with EVT from January 2020 to April 2022. We included anterior LVO involving intracranial internal carotid artery and middle cerebral artery. We analyzed baseline clinical and radiological variables associated with ICAS-LVO and evaluated the diagnostic value of a multivariate logistic regression model to identify ICAS-LVO before EVT. ICAS-LVO was defined as presence of angiographic residual stenosis or a trend to re-occlusion during EVT procedure. A total of 338 patients were included in the study. Of them, 28 patients (8.3%) presented with ICAS-LVO. After adjusting for confounders, absence of atrial fibrillation (OR 9.33, 95% CI 1.11-78.42; p = 0.040), lower hypoperfusion intensity ratio (HIR [Tmax > 10 s/Tmax > 6 s ratio], (OR 0.69, 95% CI 0.50-0.95; p = 0.025), symptomatic intracranial artery calcification (IAC, OR .15, 95% CI 1.64-26.42, p = 0.006), a more proximal occlusion (ICA, MCA-M1: OR 4.00, 95% CI 1.23-13.03; p = 0.021), and smoking (OR 2.91, 95% CI 1.08-7.90; p = 0.035) were associated with ICAS-LVO. The clinico-radiological model showed an overall well capability to identify ICAS-LVO (AUC = 0.88, 95% CI 0.83-0.94; p < 0.001). In conclusion, a combination of clinical and radiological features available before EVT can help to identify an ICAS-LVO. This approach could be useful to perform a rapid assessment of underlying etiology and suggest specific pathophysiology-based measures. Prospective studies are needed to validate these findings in other populations.

Granulocytes-Rich Thrombi in Cerebral Large Vessel Occlusion Are Associated with Increased Stiffness and Poorer Revascularization Outcomes

We aim to identify a profile of intracranial thrombus resistant to recanalization by mechanical thrombectomy (MT) in acute stroke treatment. The first extracted clot of each MT was analyzed by flow cytometry obtaining the composition of the main leukocyte populations: granulocytes, monocytes, and lymphocytes. Demographics, reperfusion treatment, and grade of recanalization were registered. MT failure (MTF) was defined as final thrombolysis in cerebral infarction score IIa or lower and/or need of permanent intracranial stenting as a rescue therapy. To explore the relationship between stiffness of intracranial clots and cellular composition, unconfined compression tests were performed in other cohorts of cases. Thrombi obtained in 225 patients were analyzed. MTF were observed in 30 cases (13%). MTF was associated with atherosclerosis etiology (33.3% vs. 15.9%; p = 0.021) and higher number of passes (3 vs. 2; p < 0.001). Clot analysis of MTF showed higher percentage of granulocytes [82.46 vs. 68.90% p < 0.001] and lower percentage of monocytes [9.18% vs.17.34%, p < 0.001] in comparison to successful MT cases. The proportion of clot granulocytes (aOR 1.07; 95% CI 1.01-1.14) remained an independent marker of MTF. Among thirty-eight clots mechanically tested, there was a positive correlation between granulocyte proportion and thrombi stiffness (Pearson's r = 0.35, p = 0.032), with a median clot stiffness of 30.2 (IQR, 18.9-42.7) kPa. Granulocytes-rich thrombi are harder to capture by mechanical thrombectomy due to increased stiffness, so a proportion of intracranial granulocytes might be useful to guide personalized endovascular procedures in acute stroke treatment.

Abstract 95: High Proportion Of Granulocytes Form Intracranial Thrombus Is Associated With Increased Stiffness And Resistance To Endovascular Recanalization

Hypothesis: We aim to identify a profile of intracranial thrombus resistant to recanalization by standard mechanical thrombectomy (MT) in acute stroke treatment.

Methods: First extracted clot of each MT were analyzed by Flow Cytometry obtaining composition of main leukocyte populations: granulocytes, monocytes and lymphocytes. Demographics, reperfusion treatment and grade of recanalization were registered. MT Failure ( MTF) was defined as final Thrombolysis in Cerebral Infarction score IIa or lower and/ or need of permanent intracranial stenting as a rescue therapy after standard MT. In other cohort of cases, unconfined compression tests were performed to explore stiffness of retrieved clots . We looked for correlation between mechanical characterization tests and clot composition.

Results: Among 225 patients, there were 13 % of MTF that were significantly associated to atherosclerosis etiology ( 33.3% vs. 15.9% ; p 0.021) , more passes ( 3 vs. 2; p <0.001), higher proportion of clot granulocytes ( 82.46% vs. 68.90% ; p <0.001) and lower proportion of clot monocytes ( 9.18% vs.17.34% ; p<0.001). The proportion of clot granulocytes (aOR 1.07; 95% CI 1.01-1.14) remained as an independent marker of MTF. Among Thirty eight clots tested by unconfined compression median clot stiffness was 30.2 (IQR, 18.9-42.7) kPa. There was a positive correlation between granulocyte proportion and thrombi stiffness (Pearson’s r=0.35, p=0.032).

Conclusions: There is a positive correlation between granulocyte proportion and thrombi stiffness that may explain endovascular resistance to recanalization. Influence of granulocytes within thrombus may be a target for future reperfusion treatments.

Abstract TP120: Noncontrast Ct, Single-phase Cta, And Multiphase Cta Intracerebral Hemorrhage Expansion Scores

Background: Several noncontrast computed tomography (NCCT), single-phase computed tomography angiography (CTA), and multiphase CTA markers of intracerebral hemorrhage (ICH) expansion have been previously proposed. We derived and validated three scores for the prediction of hematoma expansion depending on the use of NCCT, single-phase CTA, or multiphase CTA markers of hematoma expansion.

Methods: We prospective studied 276 consecutive patients with ICH within 6 hours from symptom onset. After deriving NCCT, single-phase CTA, and multiphase CTA scores in a 5-year period population (n=156), we validated them in a different 3-year period population (n=120). Outcome parameters included substantial hematoma expansion >6 mL or >33% at 24 hours (primary outcome) and poor outcome (mRS score >2) at 90 days.

Results: The most accurate marker of hematoma expansion was spot sign in phase 1 of multiphase CTA (80.3%). The four independent predictors of substantial hematoma expansion included in the different scores were ultraearly hematoma growth (uHG) >5 mL/h, heterogeneous density, spot sign in phase 1 of multiphase CTA, and spot sign in any phase of multiphase CTA (Table). On each of the three scores, the proportion of patients that experienced substantial hematoma expansion increased with each point increase. C-index for both substantial hematoma expansion and poor outcome in the derivation and validation cohort was lower in NCCT expansion score than in single-phase CTA expansion score which, in turn, was lower than in multiphase CTA expansion score (Table).

Conclusions: This study demonstrates the added prognostic value of more advanced CT modalities in acute ICH evaluation. Single-phase CTA score and, especially, multiphase CTA score, are more robust than NCCT score in the prediction of hematoma expansion and poor outcome. These scores may help to refine the selection of patients at risk of expansion and poorest outcomes in different decision-making scenarios.

Abstract WP4: Intravenous Thrombolysis And Outcomes In Patients With Large-vessel Stroke Directly Admitted Or Transferred To A Thrombectomy-capable Center

Objective: To assess whether the effect of intravenous thrombolysis in patients with large-vessel occlusion differed between patients directly admitted to thrombectomy-capable centers and patients transferred from local stroke centers without thrombectomy capabilities.

Methods: We included 3206 patients with an acute ischemic large-vessel stroke with first imaging within 7 hours after onset that were directly admitted to thrombectomy-capable centers and treated with thrombectomy, or transferred from local stroke centers for thrombectomy evaluation, between 2017 and 2021 in Catalonia, Spain. Primary outcome was the degree of disability at 90 days, as evaluated by the shift analysis on the mRs score. Secondary outcomes included mortality at 90 days and the rate of parenchymal hemorrhage and successful reperfusion. Inverse-probability weighting clustered at the type of stroke center was used to estimate the effects.

Results: The analysis included 2268 patients (975[49%] treated with thrombolysis) directly admitted to thrombectomy-capable centers and 938 patients (580[66%] treated with thrombolysis and 616[67%] treated with thrombectomy) transferred from local stroke centers (mean age 72±13 years, median NIHSS score 17[IQR 12-21], 1363 female[48%]). Patients treated with intravenous thrombolysis were younger, had shorter time from onset to first image acquisition, and higher rates of wake-up stroke, atrial fibrillation and anticoagulation intake. The effect of intravenous thrombolysis on the primary outcome was similar in patients directly admitted to thrombectomy-capable centers (acOR 1.50, 95% CI 1.24-1.81) and patients transferred from local stroke centers (acOR 1.44, 95% CI 1.04 to 2.01)(p interaction =0.68). Patients treated with intravenous thrombolysis had lower mortality rate, higher rate of parenchymal hematoma and similar rate of successful reperfusion, with no difference according to type of center (p interaction >0.1).

Conclusion: Administration of intravenous thrombolysis in patients with a large-vessel stroke with intention to thrombectomy was associated with higher odds of good functional outcome and higher rates of parenchymal hematoma, independently of the type of stroke center were it was administered.

Systematic CT perfusion acquisition in acute stroke increases vascular occlusion detection and thrombectomy rates

BACKGROUND

In patients with stroke, current guidelines recommend non-invasive vascular imaging to identify intracranial vessel occlusions (VO) that may benefit from endovascular treatment (EVT). However, VO can be missed in CT angiography (CTA) readings. We aim to evaluate the impact of consistently including CT perfusion (CTP) in admission stroke imaging protocols.

METHODS

From April to October 2020 all patients admitted with a suspected acute ischemic stroke underwent urgent non-contrast CT, CTA and CTP and were treated accordingly. Hypoperfusion areas defined by time-to-maximum of the tissue residue function (Tmax) >6 s, congruent with the clinical symptoms and a vascular territory, were considered VO (CTP-VO). In addition, two experienced neuroradiologists blinded to CTP but not to clinical symptoms retrospectively evaluated non-contrast CT and CTA to identify intracranial VO (CTA-VO).

RESULTS

Of the 338 patients included in the analysis, 157 (46.5%) presented with CTP-VO (median Tmax >6s: 73 (29-127) mL). CTA-VO was identified in 83 (24.5%) of the cases. Overall CTA-VO sensitivity for the detection of CTP-VO was 50.3% and specificity was 97.8%. Higher hypoperfusion volume was associated with increased CTA-VO detection (OR 1.03; 95% CI 1.02 to 1.04). EVT was performed in 103 patients (30.5%; Tmax >6s: 102 (63-160) mL), representing 65.6% of all CTP-VO. Overall CTA-VO sensitivity for the detection of EVT-VO was 69.9% and specificity was 95.3%. Among patients who received EVT, the rate of false negative CTA-VO was 30.1% (Tmax >6s: 69 (46-99.5) mL).

CONCLUSION

Systematically including CTP in acute stroke admission imaging protocols may increase the diagnosis of VO and rate of EVT.

Abstract 26: Timing The Optimal Transfer Modality For Suspected Large-vessel Stroke Patients: A Post-hoc Analysis Of The Racecat Trial

Introduction: Current recommendations for regional stroke destination suggest that patients with an acute severe stroke should be triaged based on estimated time to arrival to a thrombectomy-capable center. We aimed to evaluate which time period available at the time that patient is triaged is able to discriminate which transfer modality should be chosen.

Methods: We built and ordered logistic regression model adjusted for multiple comparisons with the RACECAT trial population using time periods available during triage: time from onset to emergency medical services (EMS) evaluation, estimated time of arrival to the thrombectomy-capable center and between centers distance. Estimated times were computed using a distance matrix API. Primary outcome was disability at 90 days, as assessed by the shift analysis on the modified Rankin score.

Results: Of the 1369 patients evaluated, median time from onset to EMS evaluation, estimated time to arrival to the thrombectomy-capable center and between centers distances were 65 minutes (interquartile ratio (IQR) 43 to 138), 61 minutes (IQR 36 to 80) and 62 minutes (IQR 36 to 73), respectively. In patients transferred to local stroke centers, delay in EMS evaluation was associated with higher degrees of disability (for each 30 minutes delay, adjusted common odds ratio (acOR) 1.035, 97.5% confidence interval (CI) 1.005 to 1.066), with no influence in patients directly transferred to thrombectomy-capable centers (for each 30 minutes delay, acOR 0.999, 97.5% CI 0.981 to 1.018) (p interaction =0.048). In patients evaluated by EMS above 120 minutes after stroke onset, direct transfer to a thrombectomy-capable center was associated with lower degrees of disability (acOR 1.494, 95% CI 1.026 to 2.174).

Conclusion: In the RACECAT trial, delay in EMS evaluation was associated with higher degrees of disability in patients transferred to local stroke centers and may serve as a potential biomarker for prehospital triage optimization.

Abstract WMP66: Multiparametric Neuroimaging And Its Association With Non-Contrast Computed Tomography In Late Window Large Vessel Occlusion Acute Stroke

Background: Endovascular treatment (EVT) for acute ischemic stroke (AIS) between 6 to 24 hours is established as a standard of care among patients selected by multiparametric neuroimaging. Therefore, we aimed to explore neuroimaging parameters in late window AIS large vessel occlusion (LVO) patients and the association between findings in non-contrast computed tomography (NCCT) and multiparametric CT.

Methods: We included consecutive AIS patients within 6-24 hours from symptoms onset with CTA-LVO. We studied potential associations between computed tomography mismatch defined by DAWN and/or DEFUSE-3 neuroimaging criteria (CTP-MM), infarct volume on CTP, and ASPECTS on NCCT. We also analyzed the association between neuroimaging parameters and outcome determined by 90-day mRS.

Results: We included 206 patients, of which 176 (85.4%) presented CTP-MM and 184 (89.3%) presented with an ASPECTS ≥ 6 on admission. The rate of CTP-MM was 90.8% in patients with ASPECTS ≥ 6, as compared with 40.9% in those with low ASPECTS [Figure 1A] . The ASPECTS correlated with infarct core, determined by Cerebral Blood Flow <30% volume (rP=-0.575, P<0.001). In EVT-treated patients (185, 89.8%), after adjusting for identifiable confounders, the presence of CTP-MM was a predictor of 90-day functional independence (OR 3.38; 95%CI 1.01-11.29; P=0.048). We did not find an association between CTP-MM and 90-day functional disability (ordinal mRS shift, aOR 1.39; 95% CI 0.58-3.34; P=0.459) [Figure 1B] .

Conclusions: A great majority of patients who presented a LVO in late window fulfilled guidelines imaging criteria to undergo EVT, especially those with high ASPECTS (≥ 6). Our data suggest that NCCT with CT angiography is a reasonable approach for acute ischemic stroke treatment selection also in the late window.

Monocyte-to-Lymphocyte Ratio in Clot Analysis as a Marker of Cardioembolic Stroke Etiology

The aim of the study was to find markers of high-risk cardioembolic etiology (HRCE) in patients with cryptogenic strokes (CS) through the analysis of intracranial clot by flow cytometry (FC). A prospective single-center study was designed including patients with large vessel occlusion strokes. The percentage of granulocytes, monocytes, lymphocytes, and monocyte-to-lymphocyte ratio (MLr) were analyzed in clots extracted after endovascular treatment (EVT) and in peripheral blood. Large arterial atherosclerosis (LAA) strokes and high-risk cardioembolic (HRCE) strokes were matched by demographics and acute reperfusion treatment data to obtain FC predictors for HRCE. Multilevel decision tree with boosting random forest classifiers was performed with each feature importance for HRCE diagnosis among CS. We tested the validity of the best FC predictor in a cohort of CS that underwent extensive diagnostic workup. Among 211 patients, 178 cases underwent per-protocol workup. The percentage of monocytes (OR 1.06, 95% CI 1.01-1.11) and MLr (OR 1.83, 95% CI 1.12-2.98) independently predicted HRCE diagnosis when LAA clots (n = 28) were matched with HRCE clots (n = 28). Among CS (n = 82), MLr was the feature with the highest weighted importance in the multilevel decision tree as a predictor for HRCE. MLr cutoff point of 1.59 yield sensitivity of 91.23%, specificity of 44%, positive predictive value of 78.79%, and negative predictive value of 68.75 for HRCE diagnosis among CS. MLr ≥ 1.6 in clot analysis predicted HRCE diagnosis (OR, 6.63, 95% CI 1.85-23.71) in a multivariate model adjusted for age. Clot analysis by FC revealed high levels of monocyte-to-lymphocyte ratio as an independent marker of cardioembolic etiology in cryptogenic strokes.

Direct to Angiography Suite Without Stopping for Computed Tomography Imaging for Patients With Acute Stroke: A Randomized Clinical Trial

Importance

Direct transfer to angiography suite (DTAS) for patients with suspected large vessel occlusion (LVO) stroke has been described as an effective and safe measure to reduce workflow time in endovascular treatment (EVT). However, it is unknown whether DTAS improves long-term functional outcomes.

Objective

To explore the effect of DTAS on clinical outcomes among patients with LVO stroke in a randomized clinical trial.

Design, Setting, and Participants

The study was an investigator-initiated, single-center, evaluator-blinded randomized clinical trial. Of 466 consecutive patients with acute stroke screened, 174 with suspected LVO acute stroke within 6 hours of symptom onset were included. Enrollment took place from September 2018 to November 2020 and was stopped after a preplanned interim analysis. Final follow-up was in February 2021.

Interventions

Patients were randomly assigned (1:1) to follow either DTAS (89 patients) or conventional workflow (85 patients received direct transfer to computed tomographic imaging, with usual imaging performed and EVT indication decided) to assess the indication of EVT. Patients were stratified according to their having been transferred from a primary center vs having a direct admission.

Main Outcomes and Measures

The primary outcome was a shift analysis assessing the distribution of the 90-day 7-category (from 0 [no symptoms] to 6 [death]) modified Rankin Scale (mRS) score among patients with LVO whether or not they received EVT (modified intention-to-treat population) assessed by blinded external evaluators. Secondary outcomes included rate of EVT and door-to-arterial puncture time. Safety outcomes included 90-day mortality and rates of symptomatic intracranial hemorrhage.

Results

In total, 174 patients were included, with a mean (SD) age of 73.4 (12.6) years (range, 19-95 years), and 78 patients (44.8%) were women. Their mean (SD) onset-to-door time was 228.0 (117.9) minutes, and their median admission National Institutes of Health Stroke Scale score was 18 (interquartile range [IQR], 14-21). In the modified intention-to-treat population, EVT was performed for all 74 patients in the DTAS group and for 64 patients (87.7%) in the conventional workflow group (P = .002). The DTAS protocol decreased the median door-to-arterial puncture time (18 minutes [IQR, 15-24 minutes] vs 42 minutes [IQR, 35-51 minutes]; P < .001) and door-to-reperfusion time (57 minutes [IQR, 43-77 minutes] vs 84 minutes [IQR, 63-117 minutes]; P < .001). The DTAS protocol decreased the severity of disability across the range of the mRS (adjusted common odds ratio, 2.2; 95% CI, 1.2-4.1; P = .009). Safety variables were comparable between groups.

Conclusions and Relevance

For patients with LVO admitted within 6 hours after symptom onset, this randomized clinical trial found that, compared with conventional workflow, the use of DTAS increased the odds of patients undergoing EVT, decreased hospital workflow time, and improved clinical outcome.

Trial Registration

ClinicalTrials.gov Identifier: NCT04001738.

Abstract P318: Ischemic Core Overestimation on Computed Tomography Perfusion

Introduction: Different studies have pointed that CT perfusion(CTP) could overestimate ischemic core in early time window. We aim to evaluate the influence of time and collateral status on ischemic core overestimation.

Methods: Retrospective single-center study including patients with anterior circulation large-vessel stroke that achieved reperfusion after endovascular treatment. Ischemic core and collateral status were automatically estimated on baseline CTP using available software. CTP-derived core was considered as tissue with a relative reduction of cerebral blood flow <30%. Collateral status was assessed using the hypoperfusion intensity ratio(defined by the proportion of the Tmax>6 seconds with Tmax>10 seconds, HIR). Final infarct was measured on 24-48 hours non-contrast CT. Ischemic core overestimation was considered when CTP-derived core was larger than final infarct.

Results: Four-hundred and seven patients were included in the analysis. Median CTP-derived core and final infarct were 7mL(IQR 0-27) and 20mL(IQR 5-55), respectively. Median HIR was 0.46(IQR 0.23-0.59). 83 patients(21%) presented ischemic core overestimation(median overestimation, 12mL(IQR 5-41)). Multivariable logistic regression analysis adjusted by CTP-derived core and confounding variables showed that poor collateral status (per 0.1 HIR increase, adjusted odds ratio(aOR) 1.41, 95% confidence interval(CI)1.20-1.65) and earlier onset to imaging time(per 60 minutes earlier, aOR 1.14, CI1.04-1.25) were independently associated with ischemic core overestimation. No significant association was found with imaging to reperfusion time(per 30 minutes earlier, aOR 1.17 CI0.96-1.44). Poor collateral status influence on ischemic core overestimation differed according to onset to imaging time, with a stronger size of effect on early imaging patients(pinteraction<0.01).

Conclusion: In patients with large vessel stroke that achieve reperfusion after endovascular therapy, poor collateral status might induce higher rates of ischemic core overestimation on CTP, especially in patients in earlier window time. CTP reflects a hemodynamic state rather than tissue fate; collateral status and onset to imaging time are important factors to estimate ischemic core on CTP.

Spontaneous systolic blood pressure drop early after mechanical thrombectomy predicts dramatic neurological recovery in ischaemic stroke patients

Introduction

Spontaneous blood pressure drop within the first 24 h has been reported following arterial recanalisation in ischaemic stroke patients. We aimed to assess if spontaneous blood pressure drop within the first hour after mechanical thrombectomy is a marker of early neurological recovery.

Patients and methods

Retrospective observational single-centre study including ischaemic stroke patients treated with mechanical thrombectomy. Blood pressure parameters from admission, mechanical thrombectomy start, mechanical thrombectomy end and hourly within 24 h after mechanical thrombectomy were reviewed. Primary outcome was early dramatic neurological recovery (8-point-reduction in NIHSS or NIHSS ≤ 2 at 24 h). Secondary outcome was functional independence at 90 days (mRankin 0-2).

Results

We included 458 patients in our analysis. Two-hundred (43.7%) patients achieved dramatic neurological recovery following mechanical thrombectomy. One hour after mechanical thrombectomy end, median systolic blood pressure was significantly different between outcome groups (129 vs. 138 mmHg, p = 0.005) and a higher drop in median systolic blood pressure was seen in the dramatic neurological recovery group (15 vs. 9 mmHg). Optimal cut-off for predicting dramatic neurological recovery was a systolic blood pressure drop of 10.5 mmHg (sensitivity 0.54, specificity 0.55, AUC 0.55). On multivariate analysis, spontaneous systolic blood pressure drop was associated with higher odds of achieving dramatic neurological recovery (OR for 10 mmHg blood pressure drop 1.14, 95% CI 1.01-1.29, p = 0.04). No significative association between any blood pressure parameter drop and functional independence at 90 days was found.

Discussion

We hypothesised that spontaneous systolic blood pressure drop is a marker of successful reperfusion and, therefore, a marker of improvement of cerebral autoregulation due to the reduced final ischaemic core.

Conclusion

Spontaneous systolic blood pressure drop after mechanical thrombectomy is an early predictor of dramatic neurological recovery.

Screening of Embolic Sources by Point-of-Care Ultrasound in the Acute Phase of Ischemic Stroke

Our objective was to evaluate hand-held echocardiography as point of care ultrasound scanning (POCUS) to detect sources of embolism in the acute phase of stroke. Prospective, unicentric observational cohort study of non-lacunar ischemic stroke patients evaluated by V Scan device. The main sources of embolism (MSEs) were classified into embolic valvulopathies and severe ventricular dysfunction. We looked for atrial fibrillation (AF) predictors in strokes of undetermined etiology. MSEs were detected in 19.23% (25/130). Large vessel occlusion (LVO) (odds ratio [OR]: 4.24, 95% confidence interval [CI]: 1.01-17.85) and chronic heart failure (OR: 13.25, 95% CI: 3.54-49.50) were independent predictors of MSEs. LVO (OR: 6.54, 95% CI: 1.62-26.27) and left atrial area >20 cm² (OR: 7.01, 95% CI: 1.75-28.09) independently predicted AF. Patients with LVO and chronic heart disease may benefit from hand-held echocardiography as part of POCUS in the acute phase of ischemic stroke. Left atrial area measured was an independent predictor of AF in strokes of undetermined etiology.

Abstract TP8: Sudden Recanalization: A Game-Changing Factor in Endovascular Treatment of Large Vessel Occlusion Strokes

Introduction: First pass recanalization (FPR) is known to be a strong predictor of good outcome in endovascular treatment (EVT) of stroke. The reasons why FPR leads to better outcome than if achieved in multiple-passes (MP) are unknown. We aim to investigate the recanalization pattern and its relation with good outcome.

Methods: 609 consecutive patients underwent EVT in the anterior circulation at a single stroke center. Demographic and imaging characteristics, number of passes and recanalization pattern were recorded. Complete recanalization was defined as mTICI2b-3 at the end of EVT. Good functional outcome was defined as modified Rankin scale (mRs) 0-2 at 90 days. Sudden recanalization(SR) was considered when mTICI score varied from 0-1 to 2B-3 in a single pass. Progressive recanalization (PR) was considered if mTICI 2a was achieved at an interim pass before achieving complete recanalization. Patients were categorized as recanalizers at first-pass (FP) and multiple-passes (MP) or non-recanalizers (NR). 70 (10.3%) patients in MP group were excluded due to missing procedural data.

Results: 509 (83.9%) patients achieved complete recanalization. SR was achieved in 378 (62.1%) patients; 280 (46%) were FP-SR and 98 (16.1%) were MP-SR. MP-PR was achieved in 131 (21.5%) patients. Rates of good functional outcome depending on recanalization pattern were: FP-SR 57.5%, MP-SR 57.1% (FP-SR vs MP-SR, OR 0.9 CI 0.53-1.54, p=0.7), MP-PR 29.8% (MP-SR vs MP-PR, OR 3.06 CI 1.66-5.62, p<0.001) and NR 17% (MP-PR vs NR, OR 1.23 CI 0.49-3.09, p=0.66). In patients with complete recanalization, univariate analysis showed that both FP (OR 1.91, CI 1.34-2.72, p<0.01) and SR (OR 3.18, CI 2.08-4.87, p<0.01) were associated with good functional outcome. Multivariate analysis showed that SR was a predictor of good functional outcome (OR 3.12, CI 1.9-5.1, p<0.01), being FPR non-significant (OR 1.12, CI 0.66-1.9, p=0.666).

Conclusions: Sudden recanalization is a strong predictor of good functional outcome in patients undergoing EVT, even after previous unsuccessful attempts. Progressive recanalization may reflect clot fragmentation and embolization due to more friable composition, leading to worse outcomes. Benefits of first pass effect are driven by sudden recanalization.

Abstract TP128: Determinants of Hemorrhagic Transformation After Emergent Extracranial Internal Carotid Artery Stenting for Tandem Occlusions

Background and Purpose: Extracranial internal carotid artery (ICA) lesion in the setting of tandem occlusions is a therapeutic challenge, and hemorrhagic transformation (HT) is one of the leading causes of poor clinical outcome. We aimed to determine determinants of HT for tandem occlusions undergoing emergent extracranial ICA stenting during endovascular treatment (EVT).

Methods: We performed a prospective, observational cohort study of consecutive patients with non-cardioembolic ischemic stroke due to tandem occlusion who underwent EVT with extracranial ICA stent placement during the procedure from April 2013 to June 2019 in a single stroke center. We compared clinical (vascular risk factors, previous antiplatelet treatment, and IV rtPA), radiological (ASPECTS at admission and in-stent thrombosis at 24 hours) and serological (platelet count, fibrinogen, total cholesterol, HDL-cholesterol, and LDL-cholesterol) parameters according to the presence of HT in 24 hours CT-scan.

Results: One-hundred and eight patients were included: 78.7% were men, mean age 68.5±14.3 years, median time from symptoms onset to treatment was 220 (150-337.5) minutes, median ASPECTS at admission was 9 (8-10). Eighty-six (79.6%) patients presented an extracranial ICA occlusion, and 22 (20.4%) a high-grade (>50%) stenosis. In 88 (81.5%) patients the etiology of extracranial ICA lesion was ateroma, and in 20 (18.5%) was a dissection. Intravenous rtPA was administered in 47 (43.5%) patients. Successful recanalization (mTICI ≥2b) was achieved in 83 (76.9%) patients, and extracranial ICA recanalization in 108 (100%) patients. Type 2 diabetes (OR 1.5, 95% CI 1.1-3.5), higher fibrinogen levels (OR 4.6, 95% CI 1.6-12.9), and ASPECTS <7 at admission (OR 2.1, 95% IC 1.1-5.1) were found as independent predictors of HT in multiple logistic regression analysis.

Conclusions: Patients with a non-cardioembolic ischemic stroke due to tandem occlusion who present type 2 diabetes, higher fibrinogen levels, or ASPECTS <7 at admission are at high risk of HT. In these particular cases, it might be useful to stent with a stent that does not need double antiplatelet treatment immediately after the procedure.

Abstract TMP88: Blood Pressure Variability Within 24 Hours After Recanalization Worsens Functional Outcome Among Patients Who Underwent Endovascular Treatment

Introduction: Systemic blood pressure (BP) should be strictly monitored and adjusted during the initial stages of stroke. Due to the impairment of cerebral autoregulation, cerebral blood flow is directly affected by systemic BP and some degree of permissive hypertension might be beneficial prior to reperfusion treatments to ensure an adequate perfusion in the ischemic tissue. However, after generalization of endovascular treatment (EVT) the rate of successful recanalization has skyrocketed and it is not well established if, once achieved, BP control should be stricter given its potential risks. We aim to explore the relation between BP and outcome among patients who underwent EVT.

Methods: This is a retrospective study of a prospectively acquired unicentric database that includes patients who underwent EVT with successful recanalization measured by a mTICI ≥2b. Hourly measuring of systolic and diastolic BP was conducted during the first 24 hours post-procedure. BP variation was measured using standard deviation (SD) and range. We explored the effects of BP on functional outcome at 3 months and safety variables.

Results: The study included 351 subjects with a mean age of 72.7+/-13.1 and 51.6% were men. The 3-months mRS was ≤2 in 50.4% of patients, 66 subjects (19.2%) presented hemorrhagic transformation and 67 (19.1%) were dead in the 3-months follow-up period. Both systolic BP SD (15.6+/-9.9 vs. 12.9+/-4.3; p<0.01) and range (55.6+/-18.4 vs. 48.7+/-16.4; p<0.01) were higher among patients with bad functional outcome (mRS>2). Subjects with hemorrhagic transformation presented higher range of DBP (35.7+/-12.4 vs. 32.0+/-11.9; p=0.03) and SBP (56.8+/-17.0 vs. 51.4+/-18.1; p=0.03) and higher diastolic DBP SD (9.3+/-4.1 vs. 8.2+/-2.7; p<0.01). In a logistic regression analysis DBP SD predicted ICH (OR 1.11, CI 1.02-1.22, p=0.01) and SBP range emerged as a predictor of poor functional outcome (OR 0.97, CI 0.96-0.99, p<0.01). No differences were detected in regard to admission BP, maximal and minimal BP or mean arterial pressure.

Conclusions: Major fluctuations in systolic and diastolic BP predict increased risk of hemorrhagic complications and poor functional outcome. Minimizing BP fluctuations may improve outcome of EVT patients after recanalization.

Abstract WMP17: Computerized Tomography Perfusion to Characterize Lack of Clinical Improvement After Recanalization in Acute Ischemic Stroke

A significant proportion of patients with acute ischemic stroke (AIS) treated with endovascular thrombectomy (EVT) present poor functional outcome despite recanalization. We aim to investigate computed tomography perfusion (CTP) patterns after EVT and their association with outcome

Methods: Prospective study of anterior large vessel occlusion AIS patients who achieved complete recanalization (defined as modified Thrombolysis in Cerebral Ischemia (TICI) 2b - 3) after EVT. CTP was performed within 30 minutes post-EVT recanalization (POST-CTP): hypoperfusion was defined as volume of time to maximal arrival of contrast (Tmax) delay ≥6 seconds in the affected territory. Hyperperfusion was defined as visual increase in cerebral blood flow (CBF) and volume (CBV) with advanced Tmax compared with the unaffected hemisphere. Dramatic clinical recovery (DCR) was defined as a decrease of ≥8 points in NIHSS score at 24h or NIHSS≤2 and good functional outcome by mRS ≤2 at 3 months.

Results: One-hundred and forty-one patients were included. 49 (34.7%) patients did not have any perfusion abnormality on POST-CTP, 60 (42.5%) showed hypoperfusion (median volume Tmax≥6s 17.5cc, IQR 6-45cc) and 32 (22.8%) hyperperfusion. DCR appeared in 56% of patients and good functional outcome in 55.3%. Post-EVT hypoperfusion was related with worse final TICI, and associated worse early clinical evolution, larger final infarct volume (p<0.01 for all) and was an independent predictor of functional outcome (OR 0.98, CI 0.97-0.99, p=0.01). Furthermore, POST-CTP identified patients with delayed improvement: in patients without DCR (n=62, 44%), there was a significant difference in post-EVT hypoperfusion volume according to functional outcome (hypoperfusion volume of 2cc in good outcome vs 11cc in poor outcome, OR 0.97 CI 0.93-0.99, p=0.04), adjusted by confounding factors. Hyperperfusion was not associated with worse outcome (p=0.45) nor symptomatic hemorrhagic transformation (p=0.55).

Conclusion: Hypoperfusion volume after EVT is an accurate predictor of functional outcome. In patients without dramatic clinical recovery, hypoperfusion predicts good functional outcome and defines a “stunned-brain” pattern. POST-CTP may help to select EVT patients for additional therapies.

Abstract WMP15: Automated Volumetric Assessment of Infarct Core in Non-Contrast Computed Tomography in Patients With Acute Ischemic Stroke Secondary to Large Vessel Occlusion

Introduction: Perfusion imaging has emerged as an imaging tool to select patients with acute ischemic stroke (AIS) secondary to large vessel occlusion (LVO) for endovascular treatment (EVT). We aim to compare an automated method to assess the infarct ischemic core (IC) in Non-Contrast Computed Tomography (NCCT) with Computed Tomography Perfusion (CTP) imaging and its ability to predict functional outcome and final infarct volume (FIV).

Methods: 494 patients with anterior circulation stroke treated with EVT were included. Volumetric assessment of IC in NCCT (eA-IC) was calculated using eASPECTS™ (Brainomix, Oxford). CTP was processed using availaible software considering CTP-IC as volume of Cerebral Blood Flow (CBF) <30% comparing with the contralateral hemisphere. FIV was calculated in patients with complete recanalization using a semiautomated method with a NCCT performed 48-72 hours after EVT. Complete recanalization was considered as modified Thrombolysis In Cerebral Ischemia (mTICI) ≥2B after EVT. Good functional outcome was defined as modified Rankin score (mRs) ≤2 at 90 days. Statistical analysis was performed to assess the correlation between EA-IC and CTP-IC and its ability to predict prognosis and FIV.

Results: Median eA-IC and CTP-IC were 16 (IQR 7-31) and 8 (IQR 0-28), respectively. 419 patients (85%) achieved complete recanalization, and their median FIV was 17.5cc (IQR 5-52). Good functional outcome was achieved in 230 patients (47%). EA-IC and CTP-IC had moderate correlation between them (r=0.52, p<0.01) and similar correlation with FIV (r=0.52 and 0.51, respectively, p<0.01). Using ROC curves, both methods had similar performance in its ability to predict good functional outcome (EA-IC AUC 0.68 p<0.01, CTP-IC AUC 0.66 p<0.01). Multivariate analysis adjusted by confounding factors showed that eA-IC and CTP-IC predicted good functional outcome (for every 10cc and >40cc, OR 1.5, IC1.3-1.8, p<0.01 and OR 1.3, IC1.1-1.5, p<0.01, respectively).

Conclusion: Automated volumetric assessment of infarct core in NCCT has similar performance predicting prognosis and final infarct volume than CTP. Prospective studies should evaluate a NCCT-core / vessel occlusion penumbra missmatch as an alternative method to select patients for EVT.

Abstract WMP70: Etiology of Stroke Based on Early Analysis of Clot Cytometry Obtained Through First Pass Technique for Mechanical Thrombectomy

Introduction: Mechanical thrombectomy is the best treatment for large vessel occlusion in acute strokes, this technique can obtain clots for further analysis.

Objective: To evaluate flow cytometry in thrombi obtained in the treatment of hyperacute stroke by mechanical thrombectomy, as a diagnostic tool in the etiological study of stroke

Methods: Consecutively, intracranial clots were obtained in the hyperacute phase of stroke with solitaire device. Cell suspensions of thrombi were prepared that were labeled by direct immunofluorescence using conjugated monoclonal antibodies. The labeled samples were acquired in a Naviostm flow cytometer (Beckman-Coulter). The following leukocyte populations were studied: granulocytes, monocytes, total lymphocytes, T lymphocytes (CD3 +), helper T lymphocytes (CD3 +, CD4 +), suppressor-cytotoxic T lymphocytes (CD3 +, CD8 +), TNK lymphocytes (CD3 +, CD56 / 16 +) , NK lymphocytes (CD3-, CD56 / 16 +) and B lymphocytes (CD19 +). The results were expressed as percentages (%). The aetiology of stroke was categorized in secondary to: major structural heart disease, atrial fibrillation, stroke of atherosclerotic etiology (severe stenosis or complicated aortic atheromatosis ulceration) or infrequent causes.

Results: 40 samples were analyzed. Clots of atherosclerotic etiology (n = 13) were associated with higher% of CD4 T lymphocytes (24.85% vs 15.83% p = 0.016), and higher% of NK (21.08% vs 17.04) % p = 0.07), also showed a tendency to a higher% LT (23.69% vs 16.46% p = 0.052). Strokes secondary to AF were associated with a higher percentage of CD8 T lymphocytes (20.24 vs 13.56 p = 0.048).

Conclussion: Analysis by flow cytometry of clots obtained in the hyperacute phase of stroke showed significant differences in the different lymphocyte populations according to the etiology

Abstract WMP40: A Comparison of Three Different Endovascular Approaches for Extracranial Internal Carotid Artery Lesions in the Setting of Tandem Occlusions

Background: Endovascular treatment (EVT) of extracranial internal carotid artery (ICA) lesions in the setting of tandem occlusions is a challenge, being angioplasty alone (AA) or angioplasty+stenting (AS) the two current approaches. Hemorrhagic transformation (HT) is a major problem when a conventional [self-expanding (SX)] stent is placed, regarding the need of early double antiplatelet therapy. Interestingly, balloon-expanding (BX) stents, due to their less thrombogenicity, may constitute an alternative, so they do not need early antiplatelets. We aimed to study differences in ICA restenosis, HT, clinical outcome and stroke recurrence between patients treated with AA or AS.

Methods: Prospective study of consecutive patients with non-cardioembolic ischemic stroke and tandem occlusions, who underwent <6hours EVT from April 2013 to April 2017. We compared rate of ICA high-degree stenosis/occlusion at 24h, HT, clinical outcome (change in NIHSS at 24h and at discharge over NIHSS at admission, and mRS≥2 at 3 months) and stroke recurrence within 3 months between AA and AS (SX and BX stents) groups.

Results: Ninety-two patients fulfilled inclusion criteria: mean age 64.6±12.6 years. Forty (43.5%) received AA and 52 (56.5%) AS (61.5% SX stents, 38.5% BX stents). Both groups were comparable in baseline characteristics. Fifty (54.3%) received IV rtPA. Patients who underwent AA presented ICA high-degree stenosis/occlusion at 24h more frequently than those who underwent AS (86.5% vs. 21.2%, p <0.001). No differences were found in HT, clinical outcome and stroke recurrence ( p >0.05 for all comparisons). In the AS group, all SX stents received antiplatelets after EVT, whereas in 75% of cases in the BX group no antiplatelets were started within 24h. However, no differences were found in ICA high-degree stenosis /occlusion at 24h, clinical outcome and stroke recurrence ( p >0.05). We neither found differences in HT. Nevertheless, all cases were asymptomatic in the BX stents group.

Conclusions: Emergent ICA stenting seems to have a lower risk of restenosis compared to AA, without a significant increase of HT and stroke recurrence or a worse clinical outcome. BX stents, without early antiplatelet therapy, are a promising alternative to conventional carotid stents.

Prehospital Systolic Blood Pressure Is Related to Intracerebral Hemorrhage Volume on Admission

BACKGROUND AND PURPOSE

Ultra-early blood pressure (BP) management in the prehospital setting could improve the efficacy of this treatment on attenuating intracerebral hemorrhage (ICH) expansion. We aimed to determine the association of prehospital systolic BP (SBP) with ICH volume, ultra-early hematoma growth, and the spot sign on admission.

METHODS

We conducted a retrospective study of a prospective database of 219 consecutive patients with spontaneous ICH admitted to the emergency department of a tertiary stroke center during a 3-year period. Prehospital SBP and ICH volume, ultra-early hematoma growth (ICH volume/onset-to-imaging time), and presence of the spot sign on admission were prospectively recorded. Primary outcome was ICH volume on admission. Secondary outcomes included ultra-early hematoma growth and frequency of the spot sign in patients scanned within 6 hours from symptom onset (hyperacute group).

RESULTS

Prehospital SBP was positively correlated with both SBP (r=0.552; P<0.001) and ICH volume (ρ=0.189; P=0.006) on admission. Patients with ICH volume above the median value presented higher prehospital SBP (172.3±35.0 versus 163.7±27.8 mm Hg; P=0.049). This association remained significant in adjusted multiple logistic regression analysis (odds ratio, 1.01 for a 1-U increase in SBP; 95% confidence interval, 1.01-1.02; P=0.018). In the hyperacute group (n=126), prehospital SBP was unrelated to ultra-early hematoma growth (ρ=0.115; P=0.203) nor the presence of the spot sign (172.2±27.6 versus 171.8±31.6 mm Hg; P=0.959).

CONCLUSIONS

Prehospital SBP is correlated with SBP on admission and independently associated with ICH volume on admission. These findings support the rationale of testing whether prehospital initiation of BP-lowering attenuates ICH expansion.

Abstract TP337: Multiphase CTA Improves ICH Expansion Prediction and Might Provide Additional Information on the Pathophysiology of the Spot Sign

Background: Although the spot sign is a strong predictor of hematoma expansion, there is no accepted consensus on the timing of CTA acquisition, mainly because its pathophysiologic significance is uncertain. We investigated the yield of the spot sign in the prediction of hematoma expansion and its pathophysiological underpinnings using multiphase CTA.

Methods: Single-center prospective observational cohort study of 123 consecutive patients with acute (<6 hours) ICH. Patients underwent multiphase CTA performed in 3 automated phases after contrast dye injection (delay of 8, 4, and 15 seconds, respectively). According to spot sign positivity in the 3 phases, patients were categorized into 1 of 4 patterns: A (+/+/-), B (+/+/+), C (-/+/+), and D (-/-/+). Outcomes included frequency of the spot sign, significant hematoma expansion at 24 hours (>33% or >6 mL, primary outcome), and absolute hematoma growth.

Results: The frequency of the spot sign was higher the later the phase of CTA was: 29.3% in phase 1, 43.1% in 2, and 46.3% in 3 ( P <0.001). The presence of the spot sign in phase 1, 2, 3, or any phase was related to significant hematoma expansion ( P <0.001 for all comparisons). Predictive values varied depending on the CTA phase, with highest PPV observed in phase 1 (63%) and highest NPV in phase 2 (88.9%). Onset to imaging time was not significantly lower the more arterial the pattern of spot sign presentation was (Figure). The frequency of significant hematoma expansion was higher the earlier the pattern of spot sign presentation: A 100%, B 59.1%, C 40%, and D 0% ( P =0.013). Absolute hematoma growth analysis showed a hierarchical distribution of patterns of spot sign presentation: A > B > C > D > no spot sign ( P =0.003, Figure).

Conclusions: Multiphase CTA improves hematoma expansion prediction and might provide additional information on the pathophysiology of the spot sign. Arterial spot signs may represent the point of active hemorrhage, and venous spot signs the site of resolved bleeding.

Abstract WP40: Quick CT Perfusion Evaluation of Leptomeningeal Collateral Circulation: Single Cortical CBV-ROI

Good collateral circulation (CC) is a strong outcome predictor in acute stroke patients. CT angiography (CTA) is wide-world available but does not provide accurate information about parenchymal status. CT perfusion (CTP) is frequently used to determine ischemic core and tissue at risk. Our aim was to identify an easy and quick method to evaluate CC status by CTP.

Methods: Consecutive ischemic stroke patients <8h from symptoms onset evaluated for reperfusion therapies were studied. Non-contrast CT, CTP and multiphase CTA were performed. Patients with confirmed M1-MCA or TICA occlusion on CTA were included. CC evaluation was determined by multiphase CTA (mCTA) according to the Calgary CC Scale and classified as poor (grades 0-2) or good (grades 3-5). In CTP maps, one single ipsi- and contralateral regions of interest (ROI) were defined in the MCA cortical territory (M4, M5, M6). We studied the association of absolute and relative to contralateral ROI-CTP values with CC degree determined by mCTA.

Results: 33 patients were included, median NIHSS 17.5 (2-22). Twenty-five patients (75.8%) presented a M1 and 8 (24.2%) a TICA occlusion. On mCTA, 27 (81.8%) patients presented with a favourable CC status and 6 (18.2%) with poor CC. Mean ROI values in the ischemic MCA territory were: CBV 3.5±1.5 ml/100mg, CBF 46.9±29.3 ml/100mg/min, MTT 8.1±3.1 s, Tmax 23.2±4.4 s. In the contralateral non-ischemic MCA, the mean ROI values were: CBV 3.48±1.4, CBF 66.5±32.7, MTT 5.6±2.3, Tmax 20.4±4.8. Absolute and relative CBV-ROI data (relCBV= ischemic CBV value / contralateral CBV value) were the only values significantly associated with CC status on mCTA (good CC mean CBV: 3.8 ml/100g VS poor CC mean CBV: 1.9, p=0.006; good CC mean relCBV 1.1 vs poor CC mean relCBV 0.6, p=0.019). A ROC curve defined 2.5 ml/100mg as the better cut-off point of ROI-CBV that identified patients with good CC status (sensitivity 96%, specificity 84%, VPP 0.96, VPN 0.83). Patients with a ROI-CBV >2.5 presented lower median NIHSS after 24 hours (4 vs 18, p= 0.012) and smaller mean infarct volume on control CT (27.9 vs 88.3, p=0.021).

Conclusion: A single cortical ROI-CBV allows an easy and quick accurate evaluation of collateral circulation in CTP. ROI-CBV>2.5 ml/100mg is related to good clinical and radiological outcomes.

Abstract TMP31: Hyperacute Extracranial Internal Carotid Artery Stenting vs Angioplasty: Which is the Best for Recanalization?

Background: Up to 20% of acute intracranial occlusions have an associated extracranial internal carotid artery (ICA) severe stenosis or occlusion, and they often need specific treatment. However, it remains unclear which is the best option for extracranial revascularization. We aimed to study differences in restenosis, complications, and stroke recurrences between patients treated with stenting and those who underwent angioplasty without stenting.

Methods: Prospective study of consecutive patients with non-cardioembolic ischemic stroke and occlusion or severe stenosis of the extracranial ICA, who underwent hyperacute endovascular procedure from April 2013 to December 2015. We divided patients depending on the extracranial treatment they received. We compared the rate of stenosis >50% or occlusion of the ICA at 24 hours (evaluated by carotid ultrasound or CTA). Besides, we analyzed differences in complications and stroke recurrences within 1 year of follow-up.

Results: From 97 patients who underwent hyperacute revascularization of the extracranial ICA, 63 fulfilled the inclusion criteria: mean age 65.6±13.6 years, median time from symptoms onset to treatment 249 [161-330] minutes. Thirty-one (49.2%) were treated with angioplasty and 32 (50.8%) with stent. Both groups were comparable in demographic data, vascular risk factors, previous treatment (including antiplatelets), and ASPECTS score. Thirty-seven (58.7%) received intravenous rtPA and 58 (92.1%) intracranial thrombectomy. Patients who underwent angioplasty presented stenosis >50% or occlusion at 24h more frequently than those who underwent stenting (67.7% vs 21.9% , p =0.002), regardless the degree of residual stenosis after the angioplasty. Thirteen (38.1%) of the angioplasties were permeable at 24 hours, nevertheless 39.1% needed a deferred stenting. There were no differences in complications, including intracranial hemorrhage, despite intravenous rtPA or early double antiplatelet therapy, as well as in stroke recurrences within 1 year ( p >0.05 for all comparisons).

Conclusions: Hyperacute extracranial ICA stenting seems to have a lower risk of restenosis compared to angioplasty, without a significant increase of complications and stroke recurrences

Prosthetic Valve Thrombosis in the Acute Phase of the Stroke: Relevance of Detection and Follow-Up

BACKGROUND

Stroke may be the first symptom of prosthetic valve thrombosis (PVT); therefore, rapid diagnosis and therapy are crucial. We aimed to evaluate the prevalence, main predictors, and long-term clinical evolution of patients with PVT in the acute phase of stroke.

METHODS

We studied consecutive acute ischemic stroke patients with prosthetic heart valves who underwent emergent transesophageal echocardiography (TEE) during a 5-year period. Two groups were defined depending on the presence of PVT (PVT or non-PVT groups). Baseline characteristics, TEE findings, and international normalized ratios (INRs) at the stroke event were registered. Follow-up visits and TEE control examinations were performed.

RESULTS

Sixty-seven patients were registered. TEE was performed within the first week in 85% of patients (n = 57). PVT was diagnosed in 41.8% of cases (n = 28). Clinical severity and baseline INR level showed no differences when the PVT and non-PVT groups were compared. The presence of PVT was associated with the mitral valve location as compared with the aortic valve location (75% versus 25%, P = .003), the presence of spontaneous echocontrast (64.3% versus 35.9%, P = .022), and low ejection fraction (66.7% versus 32.7%, P = .019). The PVT group showed a trend toward higher percentage of recurrence (10.7% versus 2.5%, P = .102) in the follow up period (mean follow-up 25 months).

CONCLUSIONS

The detection of PVT in the acute stroke phase was relevant, as the stroke recurrence rate was considerable. Therefore, all patients with prosthetic heart valve should undergo emergent TEE.

Improving the Evaluation of Collateral Circulation by Multiphase Computed Tomography Angiography in Acute Stroke Patients Treated with Endovascular Reperfusion Therapies

Good collateral circulation (CC) is associated with favorable outcomes in acute stroke, but the best technique to evaluate collaterals is controversial. Single-phase computed tomography angiography (sCTA) is widely used but lacks temporal resolution. We aim to compare CC evaluation by sCTA and multiphase CTA (mCTA) as predictors of outcome in endovascular treated patients.

METHODS

Consecutive endovascular treated patients with M1 middle cerebral artery (MCA) or terminal intracranial carotid artery (TICA) occlusion confirmed by sCTA were included. Two more CTA acquisitions with 8- and 16-second delays were performed for mCTA. Endovascular thrombectomy was performed independently of the CC status according to a local protocol [Alberta Stroke Program Early CT score (ASPECTS) >6, modified Rankin scale (mRS) score <3]. CC on sCTA and mCTA were compared.

RESULTS

108 patients were included. Their mean age was 69.6 ± 13 years and their median National Institutes of Health Stroke Scale (NIHSS) score was 17 (interquartile range 8). 79 (73.1%) had M1 MCA and 29 (26.9%) TICA occlusions. The mean time from symptom onset to CTA was 146.8 ± 96.5 min. On sCTA, 50.9% patients presented good CC vs. 57.5% on mCTA. Good CC status in both sCTA and mCTA had a lower 24-hour infarct volume (27.4 vs. 74.8 cm³ on sCTA, p = 0.04; 17.2 vs. 97.8 cm³ on mCTA, p < 0.01). However, only good CC on mCTA was associated with lower 24-hour (5 vs. 8.5, p = 0.04) and median discharge NIHSS (2 vs. 4.5, p = 0.04) scores and functional independency (mRS score <3) at 3 months (76.9 vs. 23.1%, p < 0.01). In a logistic regression model including age, NIHSS, ASPECTS and recanalization, only age (OR 0.96, 95% CI 0.93-0.99, p = 0.02) and good CC on mCTA (OR 5, 95% CI 1.99-12.6, p < 0.01) were independent predictors of functional outcome at 3 months.

CONCLUSION

CC evaluation by mCTA is a better prognostic marker than CC evaluation by sCTA for clinical and functional endpoints in acute stroke patients treated with endovascular thrombectomy.

CBV_ASPECTS Improvement over CT_ASPECTS on Determining Irreversible Ischemic Lesion Decreases over Time

The Alberta Stroke Program Early CT Score (ASPECTS) is a useful scoring system for assessing early ischemic signs on noncontrast computed tomography (CT). Cerebral blood volume (CBV) on CT perfusion defines the core lesion assumed to be irreversibly damaged. We aim to explore the advantages of CBV_ASPECTS over CT_ASPECTS in the prediction of final infarct volume according to time.

METHODS

Consecutive patients with anterior circulation stroke who underwent endovascular reperfusion according to initial CT_ASPECTS ≥7 were studied. CBV_ASPECTS was assessed blindly later on. Recanalization was defined as thrombolysis in cerebral ischemia score 2b-3. Final infarct volumes were measured on follow-up imaging. We compared ASPECTS on CBV and CT images, and defined ASPECTS agreement as: CT_ASPECTS - CBV_ASPECTS ≤1.

RESULTS

Sixty-five patients, with a mean age of 67 ± 14 years and a median National Institutes of Health Stroke Scale score of 16 (range 10-20), were studied. The recanalization rate was 78.5%. The median CT_ASPECTS was 9 (range 8-10), and the CBV_ASPECTS was 8 (range 8-10). The mean time from symptoms to CT was 219 ± 143 min. Fifty patients (76.9%) showed ASPECTS agreement. The ASPECTS difference was inversely correlated to the time from symptoms to CT (r = -0.36, p < 0.01). A ROC curve defined 120 min as the best cutoff point after which the ASPECTS difference becomes more frequently ≤1. After 120 min, 89.5% of the patients showed ASPECTS agreement (as compared with 37.5% for <120 min, p < 0.01). CBV_ASPECTS but not CT_ASPECTS correlated with final infarct (r = -0.33, p < 0.01). However, if CT was done >2 h after symptom onset, CT_ASPECTS also correlated to final infarct (r = -0.39, p = 0.01).

CONCLUSIONS

In acute stroke, CBV_ASPECTS correlates with the final infarct volume. However, when CT is performed after 120 min from symptom onset, CBV_ASPECTS does not add relevant information to CT_ASPECTS.