Impact of slice thickness on clinical utility of automated Alberta Stroke Program Early Computed Tomography Scores.

OBJECTIVES: The clinical utility of electronically derived ASPECTS (e-ASPECTS) to quantify signs of acute ischemic infarction could be demonstrated in multiple studies. Here, we aim to clinically validate the impact of CT slice thickness (ST) on the performance of e-ASPECTS software. METHODS: A consecutive series of n = 258 patients (06/2016 and 01/2019) with middle cerebral artery occlusion and subsequent treatment with mechanical thrombectomy was analyzed. The e-ASPECTS score and acute infarct volumes were calculated from baseline non-contrast CT with a software using 1-mm slice thickness (ST) (defined as ground truth) and axial reconstructions with 2-10-mm ST and correlated with baseline stroke severity (NIHSS) as well as clinical outcome (mRS) using logistic regressions. RESULTS: In comparison with the ground truth, significant differences were seen in e-ASPECTS scores with ST > 6 mm (p ≤ 0.031) and infarct volumes with ST > 4 mm (p ≤ 0.001). There was a significant correlation of lower e-ASPECTS and higher acute infarct volumes with increasing baseline NIHSS values for all ST (p ≤ 0.001, respectively), with values derived from 1 mm yielding the highest correlation for both parameters (rho, - 0.38 and 0.31, respectively). Similarly, lower e-ASPECTS and higher acute infarct volumes from all ST were significantly associated with poor outcome after 90 days (p ≤ 0.05, respectively) with values derived from 1-mm ST yielding the highest effects for both parameters (OR, 0.69 [95% CI 0.50-0.88] and 1.27 [95% CI 1.10-1.50], respectively). CONCLUSIONS: The e-ASPECTS software generates robust values for e-ASPECTS and acute infarct volumes when using ST ≤ 4 mm with ST = 1 mm yielding the best performance for predicting baseline stroke severity and clinical outcome after 90 days. KEY POINTS: • Clinical utility of automatically derived ASPECTS from computed tomography scans was shown in patients with acute ischemic stroke and treatment with mechanical thrombectomy. • Thin slices (= 1 mm) had the highest clinical utility in comparison with thicker slices (2-10 mm) by having the strongest correlation with baseline stroke severity and independent effects on clinical outcome after 90 days. • Automatically calculated acute infarct volumes possess clinical utility beyond ASPECTS and should be considered in future studies.

Association of Cerebrospinal Fluid Volume with Cerebral Vasospasm After Aneurysmal Subarachnoid Hemorrhage: A Retrospective Volumetric Analysis.

BACKGROUND: In aneurysmal subarachnoid hemorrhage (SAH), clot volume has been shown to correlate with the development of radiographic vasospasm (VS), while the role of cerebrospinal fluid (CSF) volume remains largely elusive in the literature. We evaluated CSF volume as a potential surrogate for VS in addition to SAH volume in this retrospective series. PATIENTS AND METHODS: From a consecutive cohort of aneurysmal SAH (n= 320), cases were included when angiographic evaluation for VS was performed (n= 125). SAH and CSF volumes were volumetrically quantified using an algorithm-assisted segmentation approach on initial computed tomography after ictus. Association with VS was analyzed using regression analysis. Receiver operating characteristic (ROC) curves were used to evaluate predictive accuracy of volumetric measures for VS and to identify cutoffs for risk stratification. RESULTS: Among 125 included cases, angiography showed VS in 101 (VS+), while no VS was observed in 24 (VS-) cases. In volumetric analysis, mean SAH volume was significantly larger (26.8 ± 21.1 ml vs. 12.6 ± 12.2 ml, p= 0.001), while mean CSF volume was significantly smaller (63.0 ± 31.2 ml vs. 85.7 ± 62.8, p= 0.03) in VS+ compared to VS- cases, respectively. The absence of correlation for SAH and CSF volumes (Pearson R - 0.05, p= 0.58) indicated independence of both measures of the subarachnoid compartment, which was a prerequisite for CSF to act as a new surrogate for VS not related to SAH. Regression analysis confirmed an increased risk of VS with increasing SAH (OR 1.06, 95% CI 1.02-1.11, p= 0.006), while CSF had a protective effect toward VS (OR 0.99, 95% CI 0.98-0.99, p= 0.02). SAH/CSF ratio was also associated with VS (OR 1.03, 95% CI 1.01-1.05, p= 0.015). ROC curves suggested cutoffs at 120 ml CSF and 20 ml SAH for VS stratification. Combination of variables improved stratification accuracy compared to use of SAH alone. CONCLUSION: This study provides a proof of concept for CSF correlating with angiographic VS after aneurysmal SAH. Quantification of CSF in conjunction with SAH might enhance risk stratification and exhibit advantages over traditional scores. The association of CSF has to be corroborated for delayed cerebral ischemia to further establish CSF as a surrogate parameter.

Effect of General Anesthesia versus Conscious Sedation for Stroke Thrombectomy on Angiographic Workflow in a Randomized Trial: A Post Hoc Analysis of the SIESTA Trial.

Purpose To investigate whether the sedation mode (ie, conscious sedation [CS] vs general anesthesia [GA]) affects the angiographic workflow applied for treatment of endovascular stroke in a post hoc analysis of a recent randomized controlled trial, Sedation versus Intubation for Endovascular Stroke Treatment (SIESTA). Materials and Methods SIESTA was an institutional review board-approved, single-center, prospective, randomized, parallel-group, open-label treatment trial with a blinded end-point evaluation to compare GA with CS for treatment of endovascular stroke in 73 and 77 patients, respectively. By using descriptive data from SIESTA, the influence of the mode of sedation on angiographic workflow during treatment for endovascular stroke (eg, procedure times) and other radiologic outcome parameters (eg, radiation exposure) were analyzed. The time between angiographic key steps for patients who underwent GA and CS was evaluated with t tests. P values were corrected for false discovery rate. Results The median time from groin puncture to first intracranial flow restoration with CS was 47 minutes (interquartile range [IQR], 29-70 minutes), and for GA, it was 41 minutes (IQR, 28-60 minutes) (P = .546). The median time to the end of angiography with CS was 104 minutes (IQR, 75-150 minutes), and with GA, it was 73 minutes (IQR, 53-125 minutes) (P = .052). Fluoroscopy time with CS was 49 minutes (IQR, 25-85 minutes), and with GA, it was 35 minutes (IQR, 20-74 minutes) (P = .098). The times were comparable in both groups for these measures. The time from groin puncture to the final angiographic result with GA, at 72 minutes (IQR, 45-109 minutes) was shorter than that with CS, at 98 minutes (IQR, 64-135 minutes) (P = .048). Conclusion This post hoc analysis of the single-center SIESTA trial revealed that time from groin puncture to final angiographic result was shorter with patients under GA than that with patients under CS. © RSNA, 2017 Online supplemental material is available for this article.

Classification of Bleeding Events: Comparison of ECASS III (European Cooperative Acute Stroke Study) and the New Heidelberg Bleeding Classification.

BACKGROUND AND PURPOSE: Intracranial hemorrhage (ICH) after acute ischemic stroke treatments represents a feared complication with possible prognostic implications. In recent years, ICHs were commonly classified according to the ECASS (European Cooperative Acute Stroke Study). To improve the clinical applicability and relevance, the new Heidelberg Bleeding Classification (HBC) has been proposed in 2015. Here, we compared the ECASS and HBC classification with regard to observed events and prognostic relevance. METHODS: A retrospective analysis of a prospectively compiled database of patients with acute ischemic stroke in the anterior circulation who received mechanical thrombectomy between February 2011 and March 2016 was performed. Presence of ICH after mechanical thrombectomy was evaluated on postinterventional computed tomographic imaging. ICHs were specified according to both ECASS III and HBC classification and analyzed with regard to their symptoms and outcome. RESULTS: ICHs were observed in 156 of 768 patients (20.3%). Using ECASS III classification, 101 ICHs could be unambiguously assigned, of which 28 (27.7%; 3.6% of all treated patients) were symptomatic ICHs. Using HBC, 55 additional ICHs could be categorized. Of these total 156 ICHs, 29 (18.6%; 3.8% of all treated patients) were classified as symptomatic according to HBC. CONCLUSIONS: Classification of ICH by ECASS III and HBC criteria show distinct differences. These differences warrant special attention during interpretation and comparison of scientific publications.

Influence of a combined CT/C-arm system on periprocedural workflow and procedure times in mechanical thrombectomy.

OBJECTIVE: To achieve the fastest possible workflow in ischaemic stroke, we developed a CT/C-arm system, which allows imaging and endovascular treatment on the same patient table. METHODS: This prospective, monocentric trial was conducted between October 2014 and August 2016. Patients received stroke imaging and mechanical thrombectomy under general anaesthesia (GA) or conscious sedation (CS) using our combined setup comprising a CT-scanner and a mobile C-arm X-ray device. Primary endpoint was time between stroke imaging and groin puncture. We compared periprocedural workflow and procedure times with the literature and a matched patient cohort treated with a biplane angiographic system before installation of the CT/C-arm system. RESULTS: In 50 patients with acute ischaemic stroke due to large-vessel occlusion in the anterior circulation, comparable recanalization rates were achieved by using the CT/C-arm setup (TICI2b-3:CT/C-arm-GA: 85.7%; CT/C-arm-CS: 90.9%; Angiosuite: 78.6%; p = 0.269) without increasing periprocedural complications. Elimination of patient transport resulted in a significant reduction of the time between stroke imaging and groin puncture: median, min (IQR): CT/C-arm-GA: 43 (35-52); CT/C-arm-CS: 39 (28-49); Angiosuite: 64 (48-74); p < 0.0001. CONCLUSION: The combined CT/C-arm system allows comparable recanalization rates as a biplane angiographic system and accelerates the start of the endovascular stroke treatment. KEY POINTS: • The CT/C-arm setup reduces median time from stroke imaging to groin puncture. • Mechanical thrombectomy using a C-arm device is feasible without increasing peri-interventional complications. • The CT/C-arm setup might be a valuable fallback solution for emergency procedures. • The CT/C-arm setup allows immediate control CT images during and after treatment.

Influence of Renal Function on Treatment Results after Stroke Thrombectomy.

BACKGROUND: Renal dysfunction (RD) may be associated with poor outcome in ischemic stroke patients treated with mechanical thrombectomy (MT), but data concerning this important and emerging comorbidity do not exist so far. Here, we investigated the influence of RD on postprocedural intracerebral hemorrhage (ICH), clinical outcome, and mortality in a large prospectively collected cohort of acute ischemic stroke patients treated with MT. METHODS: Consecutive patients with anterior-circulation stroke treated with MT between October 2010 and January 2016 were included. RD was defined as glomerular filtration rate (GFR) <60 mL/min/1.73 m2. In a prospective database, clinical characteristics were recorded and brain images were analyzed for the presence of ICH after treatment in all patients. Clinical outcome was assessed by the modified Rankin Scale (mRS) after 3 months. To evaluate associations between clinical factors and outcomes uni- and multivariate regression analyses were conducted. RESULTS: In total, 505 patients fulfilled all inclusion criteria (female: 49.7%, mean age: 71.0 years). RD at admission was present in 20.2%. RD patients were older and had cardiovascular risk factors more often. Multivariate regression analysis after adjustment for age, stroke severity, diabetes, hypertension, GFR, previous stroke, MT alone, or additional thrombolysis and recanalization results revealed that lower GFR was not independently associated with poor outcome (mRS 3-6; OR 1.13, 95% CI 0.99-1.28; p = 0.072) or ICH. However, lower GFR at admission was associated with a higher risk of mortality (OR 1.15, 95% CI 1.01-1.31; p = 0.038). Compared to admission, GFR values were higher at discharge (mean: 77.9 vs. 80.8 mL/min/1.73 m2; p = 0.046). CONCLUSIONS: We did not find evidence for an association of lower GFR with an increased risk of poor outcome and ICH, but lower GFR was a determinant of 90-day mortality after endovascular stroke treatment. Our findings encourage also performing MT in this relevant subgroup of acute ischemic stroke patients.

The Impact of Post-contrast Acute Kidney Injury on In-hospital Mortality After Endovascular Thrombectomy in Patients With Acute Ischemic Stroke.

Background and Purpose: Clinical outcome and mortality after endovascular thrombectomy (EVT) in patients with ischemic stroke are commonly assessed after 3 months. In patients with acute kidney injury (AKI), unfavorable results for 3-month mortality have been reported. However, data on the in-hospital mortality after EVT in this population are sparse. In the present study, we assessed whether AKI impacts in-hospital and 3-month mortality in patients undergoing EVT. Materials and Methods: From a prospectively recruiting database, consecutive acute ischemic stroke patients receiving EVT between 2010 and 2018 due to acute large vessel occlusion were included. Post-contrast AKI (PC-AKI) was defined as an increase of baseline creatinine of ≥0.5 mg/dL or >25% within 48 h after the first measurement at admission. Adjusting for potential confounders, associations between PC-AKI and mortality after stroke were tested in univariate and multivariate logistic regression models. Results: One thousand one hundred sixty-nine patients were included; 166 of them (14.2%) died during the acute hospital stay. Criteria for PC-AKI were met by 29 patients (2.5%). Presence of PC-AKI was associated with a significantly higher risk of in-hospital mortality in multivariate analysis [odds ratio (OR) = 2.87, 95% confidence interval (CI) = 1.16-7.13, p = 0.023]. Furthermore, factors associated with in-hospital mortality encompassed higher age (OR = 1.03, 95% CI = 1.01-1.04, p = 0.002), stroke severity (OR = 1.05, 95% CI = 1.03-1.08, p < 0.001), symptomatic intracerebral hemorrhage (OR = 3.20, 95% CI = 1.69-6.04, p < 0.001), posterior circulation stroke (OR = 2.85, 95% CI = 1.72-4.71, p < 0.001), and failed recanalization (OR = 2.00, 95% CI = 1.35-3.00, p = 0.001). Conclusion: PC-AKI is rare after EVT but represents an important risk factor for in-hospital mortality and for mortality within 3 months after hospital discharge. Preventing PC-AKI after EVT may represent an important and potentially lifesaving effort in future daily clinical practice.

Optimal thresholds to predict long-term outcome after complete endovascular recanalization in acute anterior ischemic stroke.

BACKGROUND: Despite complete endovascular recanalization, a significant percentage of patients with acute anterior stroke do not achieve a good clinical outcome. We analyzed optimal thresholds of relevant parameters to discern functional independence after successful endovascular recanalization and test their predictive performance. METHODS: Patients with acute anterior ischemic stroke undergoing endovascular treatment between April 2015 and November 2019 were retrospectively analyzed. Only patients with premorbid modified Rankin Scale (mRS) score <3 and complete recanalization (modified Thrombolysis In Cerebral Infarction 2c/3) were included. Optimal thresholds of the most important variables predicting functional independence (mRS 0-2 after 90 days) were calculated using receiver operating characteristic curves and their predictive performance was tested in an independent dataset using machine learning algorithms. RESULTS: Overall, 371 patients met the inclusion criteria. Optimal thresholds for the overall most important variables to predict functional independence were (1) National Institutes of Health Stroke Scale (NIHSS) score ≤5 after 24 hours (area under the curve (AUC) 0.88 (95% CI 0.84 to 0.92)); (2) Alberta Stroke Program Early CT Score (ASPECTS) ≥7 on follow-up CT (AUC 0.72 (95% CI 0.68 to 0.77)); and (3) change in NIHSS score ≥8 after 24 hours (AUC 0.70 (95% CI 0.65 to 0.74)). The performance of these thresholds to predict a good outcome using machine learning in the independent dataset was evaluated for (1) NIHSS score ≤5 after 24 hours (AUC 0.76 (95% CI 0.71 to 0.81)); (2) follow-up ASPECTS ≥7 (AUC 0.64 (95% CI 0.58 to 0.70)); (3) change in NIHSS score ≥8 after 24 hours (AUC 0.61 (95% CI 0.55 to 0.67)); and (4) the combination of all three parameters (AUC 0.84 (95% CI 0.80 to 0.88)). CONCLUSIONS: After complete recanalization in acute anterior circulation ischemic stroke, a good long-term outcome could be accurately predicted reaching NIHSS score ≤5 after 24 hours.

Mechanical Thrombectomy Using the new Solitaire™ Platinum Stent-retriever : Reperfusion Results, Complication Rates and Early Neurological Outcome.

BACKGROUND AND PURPOSE: The application of radiopaque markers to the Solitaire™ stent-retriever for better visibility during mechanical thrombectomy (MT) has the potential to alter the well-known characteristics of the device; however, it is uncertain whether this adjustment influences efficacy or safety of the enhanced stent-retriever. METHODS: Retrospective analysis of stroke databases of three comprehensive stroke centers. Our investigation was focused on technical and angiographic parameters, including procedure times, reperfusion results (thrombolysis in cerebral infarction, TICI), periprocedural complications and favorable early neurological recovery at discharge (modified Rankin scale ≤2 or National Institutes of Health Stroke Scale, NIHSS = 0 or ∆NIHSS ≥ 10), from consecutive patients with acute anterior circulation ischemic stroke treated with a Solitaire™ Platinum stent-retriever between October 2016 and March 2017. RESULTS: A total of 75 patients (male: n = 27, 36%, age in years: mean (SD): 75 (±12), median baseline NIHSS: 17 (interquartile range IQR: 11-21), n = 41, 54.7% received additional i. v. thrombolytics) were treated with a median number of 2 device passes (range: 1-5). The median time from groin puncture to final TICI was 56 min (IQR: 41-79). In 69 patients (92%) TICI 2b-3 was achieved. Early neurological recovery was seen in 47 (62.7%) patients. The following periprocedural complications occurred: vasospasms (n = 7, 9.3%), emboli into a new territory (n = 4, 5.3%), symptomatic intracranial hemorrhage (n = 3, 4%), difficulties during device delivery/deployment (n = 1, 1.3%). CONCLUSION: The usage of the Solitaire™ Platinum stent-retriever for MT in acute ischemic stroke patients was highly effective and was not accompanied by an increased periprocedural complication rate.

Prediction of intracranial hemorrhages after mechanical thrombectomy of basilar artery occlusion.

BACKGROUND: Mechanical thrombectomy (MT) achieves high recanalization rates in basilar artery occlusion (BAO). A severe complication of MT in BAO is intracranial hemorrhage (ICH). Yet, knowledge of risk factors for ICH after MT in BAO is limited. OBJECTIVE: To evaluate clinical and procedural parameters of patients treated with MT owing to BAO to identify potential risk factors for ICH-in particular, symptomatic ICH (sICH), and assess their clinical relevance. METHODS: We conducted a retrospective analysis of 101 consecutive patients presenting with BAO, who were treated with MT in our centre. Important clinical and procedural parameters were analysed as possible predictors for any ICH and sICH according to the Heidelberg Bleeding Classification using univariate tests and multivariate logistic regressions. RESULTS: ICH occurred in 25 (24.8%) patients, with a total of 7 (6.9%) developing sICH. Treatment with glycoprotein IIb/IIIa (GPIIb/IIIa) inhibitors was independently associated with any ICH (OR=24.67, 95% CI 4.90 to 124.03) and sICH (OR=7.08, 95% CI 1.36 to 36.78). Also, a longer onset-to-recanalization time increased the risk of both any ICH (OR=1.17, 95% CI 1.07 to 1.31) and sICH (OR=1.22, 95% CI 1.08 to 1.42). Higher serum glucose levels were associated with a higher incidence of any ICH (OR=1.39, 95% CI 1.06 to 1.85) and a higher risk of a fatal outcome (OR=1.03, 95% CI 1.01 to 1.05). CONCLUSION: Administration of GPIIb/IIIa inhibitor during the course of MT of BAO was identified as an important risk factor in the development of any ICH and sICH.

Endovascular stroke therapy may be safe in patients with elevated international normalized ratio.

INTRODUCTION: Endovascular therapy in acute ischemic stroke is safe and efficient. However, patients receiving oral anticoagulation were excluded in the larger trials. OBJECTIVE: To analyze the safety of endovascular therapy in patients with acute ischemic stroke and elevated international normalized ratio (INR) values. METHODS: Retrospective database review of a tertiary care university hospital for patients with anterior circulation stroke treated with endovascular therapy. Patients with anticoagulation other than vitamin K antagonists were excluded. The primary safety endpoint was defined as symptomatic intracranial hemorrhage (sICH; ECASS II definition). The efficacy endpoint was the modified Rankin scale (mRS) score after 3 months, dichotomized into favorable outcome (mRS 0-2) and unfavorable outcome (mRS 3-6). RESULTS: 435 patients were included. 90% were treated with stent retriever. 27 (6.2%) patients with an INR of 1.2-1.7 and 21 (4.8%) with an INR >1.7. 33 (7.6%) had sICH and 149 patients (34.3%) had a favorable outcome. Patients with an elevated INR did not have an increased risk for sICH or unfavorable outcome in multivariable analysis. The additional use of IV thrombolysis in patients with an INR of 1.2-1.7 did not increase the risk of sICH or unfavorable outcome. These results were replicated in a sensitivity analysis introducing an error of the INR of ±5%. They were also confirmed using other sICH definitions (Safe Implementation of Thrombolysis in Stroke (SITS), National Institute of neurological Disorders and Stroke (NINDS), Heidelberg bleeding classification). CONCLUSIONS: Endovascular therapy in patients with an elevated INR is safe and efficient. Patients with an INR of 1.2-1.7 may be treated with combined IV thrombolysis and endovascular therapy.

Outcome of patients with proximal vessel occlusion of the anterior circulation and DWI-PWI mismatch is time-dependent.

BACKGROUND AND PURPOSE: Patients with ischemic stroke and large vessel occlusion are assumed to benefit from endovascular therapy (ET) independent of the symptom onset-to-treatment time (OTT) if they present with a mismatch of diffusion- and perfusion-weighted imaging (DWI-PWI mismatch). We aimed at studying the influence of OTT on clinical outcome in these patients. METHODS: Retrospective database review in a tertiary care university hospital. All patients presented with proximal vessel occlusion of the anterior circulation and DWI-PWI mismatch. Primary outcome was the influence of OTT on modified Rankin scale (mRS) score three months after treatment, dichotomized in favourable (0-2) and unfavourable outcome (3-6). Secondary outcome was the effect of OTT on the shift of the mRS score. Patients treated within an early time window (<340min) and a late time window (≥340min) were compared. RESULTS: 139 patients were included. The rate of favourable outcome was significantly higher in patients who were treated in an early compared to those treated in a late time window (31 [49%] vs. 20 patients [27%], p=0.005). Adjusted multivariate logistic regression revealed that late treatment was an independent negative predictor of favourable outcome (odds ratio 0.39, confidence interval [0.18-0.84]; p=0.016). A shift towards higher mRS scores for late treatment was evident (p=0.015). In sensitivity analysis, OTT remained an independent predictor when evaluated as continuous variable. These findings were confirmed in patients with a comparable DWI-PWI mismatch according to the definitions from large trials (DEFUSE 2, DEFUSE 3, SWIFT-PRIME, EXTEND-IA). CONCLUSION: Outcome of patients with comparable DWI-PWI mismatch is time-dependent.