ERic Acute StrokE Recanalization: A study using predictive analytics to assess a new device for mechanical thrombectomy

Endovascular treatment of acute ischemic stroke with a fully radiopaque retriever: A randomized controlled trial

Objective

The Neurohawk retriever is a new fully radiopaque retriever. A randomized controlled non-inferiority trial was conducted to compare the Neurohawk and the Solitaire FR in terms of safety and efficacy. In order to evaluate the efficacy and safety of endovascular treatment in acute ischemic stroke (AIS) caused by intracranial atherosclerotic disease (ICAD) larger vessel occlusion (LVO), a sub-analysis was performed.

Methods

Acute ischemic stroke patients aged 18-80 years with LVO in the anterior circulation were randomly assigned to undergo thrombectomy with either the Neurohawk or the Solitaire FR. The primary efficacy endpoint was successful reperfusion (mTICI 2b-3) rate by the allocated retriever. A relevant non-inferiority margin was 12.5%. Safety outcomes were symptomatic intracranial hemorrhage (sICH) and all-cause mortality within 90 days. Secondary endpoints included first-pass effect (FPE), modified FPE, and favorable outcomes at 90 days. In subgroup analysis, the patients were divided into the ICAD group and non-ICAD group according to etiology, and baseline characteristics, angiographic, and clinical outcomes were compared.

Results

A total of 232 patients were involved in this analysis (115 patients in the Neurohawk group and 117 in the Solitaire group). The rates of successful reperfusion with the allocated retriever were 88.70% in the Neurohawk group and 90.60% in the Solitaire group (95%CI of the difference, -9.74% to 5.94%; p = 0.867). There were similar results in FPE and mFPE in both groups. The rate of sICH seemed higher in the Solitaire group (13.16% vs. 7.02%, p = 0.124). All-cause mortality and favorable outcome rates were comparable as well. In subgroup analysis, 58 patients were assigned to the ICAD group and the remaining 174 to the non-ICAD group. The final successful reperfusion and favorable outcome rates showed no statistically significant differences in two groups. Mortality within 90 days was relatively lower in the ICAD group (6.90% vs. 17.24%; p = 0.054).

Conclusion

The Neurohawk retriever is non-inferior to the Solitaire FR in the mechanical thrombectomy of large vessel occlusion-acute ischemic stroke (LVO-AIS). The sub-analysis suggested that endovascular treatment including thrombectomy with the retriever and essential rescue angioplasty is effective and safe in AIS patients with intracranial atherosclerotic disease-larger vessel occlusion (ICAD-LVO).

Clinical trial registration

https://clinicaltrials.gov/ct2/show/NCT04995757, number: NCT04995757.

Efficacy and Safety of a Novel Thrombectomy Device in Patients With Acute Ischemic Stroke: A Randomized Controlled Trial

Purpose: The Tonbridge stent is a novel retriever with several design improvements which aim to achieve promising flow reperfusion in the treatment of acute ischemic stroke (AIS). We conducted a randomized controlled, multicenter, non-inferiority trial to compare the safety and efficacy of the Tonbridge stent with the Solitaire FR. Methods: AIS patients aged 18-85 years with large vessel occlusion in anterior circulation who could undergo puncture within 6 h of symptom onset were included. Randomization was performed on a 1:1 ratio to thrombectomy with either the Tonbridge stent or the Solitaire FR. The primary efficacy endpoint was successful reperfusion using a modified thrombolysis in cerebral infarction score (mTICI) of 2b/3. Safety outcomes were symptomatic intracranial hemorrhage (sICH) within 24 ± 6 h and all-cause mortality within 90 days. A clinically relevant non-inferiority margin of 12% was chosen as the acceptable difference between groups. Secondary endpoints included time from groin puncture to reperfusion, National Institutes of Health Stroke Scale (NIHSS) score at 24 h and at 7 days, and a modified Rankin Scale (mRS) score of 0-2 at 90 days. Results: A total of 220 patients were enrolled; 104 patients underwent thrombectomy with the Tonbridge stent and 104 were treated with the Solitaire FR. In all test group patients, the Tonbridge was used as a single retriever without rescuing by other thrombectomy devices. Angioplasty with balloon and/or stent was performed in 26 patients in the Tonbridge group and 16 patients in the Solitaire group (p = 0.084). Before angioplasty, 86.5% of those in the Tonbridge group and 81.7% of those in the Solitaire group reached successful reperfusion (p = 0.343). Finally, more patients in the Tonbridge group achieved successful reperfusion (92.3 vs. 84.6%, 95% CI of difference value 0.9-16.7%, p < 0.0001). There were no significant differences on sICH within 24 ± 6 h between the two groups. All-cause mortality within 90 days was 13.5% in the Tonbridge group and 16.3% in the Solitaire group (p = 0.559). We noted no significant differences between groups on the NIHSS at either 24 h or 7 days and the mRS of 0-2 at 90 days. Conclusion: The trial indicated that the Tonbridge stent was non-inferior to the Solitaire FR within 6 h of symptom onset in cases of large vessel occlusion stroke. Clinical Trial Registration:ClinicalTrials.gov, number: NCT03210623.

Artificial intelligence in stroke imaging: Current and future perspectives

Artificial intelligence (AI) is a fast-growing research area in computer science that aims to mimic cognitive processes through a number of techniques. Supervised machine learning, a subfield of AI, includes methods that can identify patterns in high-dimensional data using labeled 'ground truth' data and apply these learnt patterns to analyze, interpret, or make predictions on new datasets. Supervised machine learning has become a significant area of interest within the medical community. Radiology and neuroradiology in particular are especially well suited for application of machine learning due to the vast amount of data that is generated. One devastating disease for which neuroimaging plays a significant role in the clinical management is stroke. Within this context, AI techniques can play pivotal roles for image-based diagnosis and management of stroke. This overview focuses on the recent advances of artificial intelligence methods - particularly supervised machine learning and deep learning - with respect to workflow, image acquisition and reconstruction, and image interpretation in patients with acute stroke, while also discussing potential pitfalls and future applications.

Ischemic lesion growth in acute stroke: Water uptake quantification distinguishes between edema and tissue infarct

Infarct growth from the early ischemic core to the total infarct lesion volume (LV) is often used as an outcome variable of treatment effects, but can be overestimated due to vasogenic edema. The purpose of this study was (1) to assess two components of early lesion growth by distinguishing between water uptake and true net infarct growth and (2) to investigate potential treatment effects on edema-corrected net lesion growth. Sixty-two M1-MCA-stroke patients with acute multimodal and follow-up CT (FCT) were included. Ischemic lesion growth was calculated by subtracting the initial CTP-derived ischemic core volume from the LV in the FCT. To determine edema-corrected net lesion growth, net water uptake of the ischemic lesion on FCT was quantified and subtracted from the volume of uncorrected lesion growth. The mean lesion growth without edema correction was 20.4 mL (95% CI: 8.2-32.5 mL). The mean net lesion growth after edema correction was 7.3 mL (95% CI: -2.1-16.7 mL; p < 0.0001). Lesion growth was significantly overestimated due to ischemic edema when determined in early-FCT imaging. In 18 patients, LV was lower than the initial ischemic core volume by CTP. These apparently "reversible" core lesions were more likely in patients with shorter times from symptom onset to imaging and higher recanalization rates.

ERASER

Background and Purpose- Using a novel study design with virtual comparators based on predictive modeling, we investigated whether next-generation mechanical thrombectomy devices improve outcomes in patients with ischemic stroke. We hypothesized that this new study design shows that a next-generation mechanical thrombectomy system is superior to intravenous tPA (tissue-type plasminogen activator) therapy (IVT) alone. Methods- ERASER (Eric Acute Stroke Recanalization) was an investigator-initiated, prospective, multicenter, single-arm (virtual 2-arm) study that evaluated the effectiveness of a new recanalization device together with a specific intermediate catheter (Embolus Retriever with Interlinked Cages/SOFIA, Microvention) in stroke patients with internal carotid artery or middle cerebral artery occlusions. The primary end point was the volume of saved tissue. Volume of saved tissue was defined as the difference of actual infarct volume and brain volume predicted to develop infarction using a machine learning model based on data from intravenous tPA therapy patients. Results- Eighty-one patients were enrolled. The median patient age was 71 years (interquartile range, 61-77). National Institutes of Health Stroke Scale score was 14 (interquartile range, 12-18). The actual infarct volume was smaller than predicted by the intravenous tPA therapy model, with a median volume of saved tissue of 50 mL (interquartile range, 19-103; P<0.0001). Good clinical outcome (modified Rankin Scale, 0-2 at 90 days) was observed in 48 out of 69 (70%). The recanalization rate (Thrombolysis in Cerebral Infarction 2b/3) was 95%. Conclusions- ERASER is the first mechanical thrombectomy study with a primary end point based on predictive analytics enabling intraindividual virtual comparisons. The next-generation mechanical thrombectomy method resulted in smaller infarcts than predicted after intravenous tPA therapy alone and showed a high rate of good clinical outcome. The novel study design with virtual comparisons is promising for further application and testing in the neurovascular arena. Clinical Trial Registration- URL: https://www.clinicaltrials.gov . Unique identifier: NCT02534701.