eLetters

11 e-Letters

published between 2020 and 2023

  • Cost-effectiveness of Endovascular treatment for Acute Ischemic Stroke in Japan

    Dear Editor,
    I am writing to provide a thorough assessment of the recently published study titled "Cost-effectiveness of Endovascular Therapy for Acute Stroke with a Large Ischemic Region in Japan: Impact of the Alberta Stroke Program Early CT Score on Cost-effectiveness" [1]. While the study addresses important aspects of the economic implications of endovascular therapy (EVT) for acute ischemic stroke (AIS) in Japan, my analysis aims to delve deeper into specific methodological considerations and discuss the applicability of the study's findings in a broader context.
    The primary focus of the study is the cost-effectiveness of EVT based on the Alberta Stroke Program Early CT Score (ASPECTS) for patients with AIS involving a large ischemic region. The conclusion that EVT is cost-effective for individuals with ASPECTS of 3–5 as determined by treating neurologists using MRI raises questions about the reliability and consistency of ASPECTS as a determinant of cost-effectiveness. Furthermore, the study acknowledges the variability in incremental costs and quality-adjusted life years (QALYs) associated with EVT in Japan compared to other countries. The higher incremental costs in Japan, attributed to the specific stroke care system and the frequent use of combined techniques and MRI, present challenges when applying these findings to healthcare systems with different cost structures and resource allocations.
    The study acknowledges the variabilit...

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  • Delving Deeper into the Correlation between Liquid Embolic Surface Area and Chronic Subdural Hematoma Resolution in Middle Meningeal Artery Embolization

    Dear Editor,
    I would like to commend the authors for their insightful study titled "Liquid embolic surface area as a predictor of chronic subdural hematoma resolution in middle meningeal artery embolization" [1]. The investigation into the correlation between liquid embolic surface area (LEA SA) and chronic subdural hematoma (cSDH) resolution in the context of middle meningeal artery embolization (MMAE) presents valuable contributions to the field. The authors employed a meticulous approach, retrospectively collecting data from 74 patients who underwent first-line MMAE with ethylene vinyl alcohol (EVOH) and utilizing 3D segmentation to quantify LEA SA. The observed correlation between greater LEA SA and enhanced cSDH resolution rates at 3 months and 6 months post-embolization is a noteworthy contribution to the field.
    The study's strength lies in its unique focus on a patient group undergoing first-line MMAE for cSDH, a subset that has been relatively underrepresented in the existing literature. The authors rightly acknowledge the potential selection bias in this group, considering patients with greater midline shift or poor neurologic exams might be directed immediately to surgical treatment. Nonetheless, the results support the utilization of upfront MMAE in patients with riskier surgical profiles due to comorbidities or borderline radiographic and clinical features.
    However, it is essential to scrutinize the limitations outlined by the a...

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  • The Ongoing Debate Over Dual Antiplatelet Therapy in Cerebral Aneurysm Treatment

    Dear Editor,
    I am writing to address the significant findings presented in the article "Short- versus long-term Dual AntiPlatelet Therapy for Stent-Assisted treatment of CErebral aneurysm (DAPTS ACE)." This research, a randomized clinical trial aimed at unraveling the ideal duration of Dual AntiPlatelet Therapy (DAPT) after stent-assisted coil embolization (SACE) for cerebral aneurysms, raises crucial questions regarding the management of these delicate cases.
    The article reports that the trial, DAPTS ACE, investigated whether extending DAPT for 12 months could effectively reduce the risk of ischemic stroke in comparison to a shorter 3-month DAPT regimen for patients who underwent SACE for cerebral aneurysms. The study, conducted in 17 hospitals in Japan, enrolled 142 patients between November 4, 2016, and January 7, 2019, and assigned them randomly to either the long-term or short-term DAPT group. The primary outcome was the occurrence of ischemic stroke events during the period of 3 to 12 months after SACE.
    The results are undeniably important, as they indicate that there was no statistically significant difference in the rate of ischemic strokes between the long-term and short-term DAPT groups. In fact, ischemic stroke was a rare occurrence in both groups, and the data show that the extended duration of DAPT did not offer a significant advantage in preventing ischemic events. This is the first randomized controlled trial to tackle the duratio...

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  • Analysis of Intracranial Hemorrhagic Complications in Anterior Circulation Endovascular Thrombectomy

    To the Editor,

    I am writing to discuss the recent article titled "Incidence of intracranial hemorrhagic complications after anterior circulation endovascular thrombectomy in relation to occlusion site: a nationwide observational register study" (1). This study provides valuable insights into intracranial hemorrhage (ICH) as a potential complication of endovascular thrombectomy (EVT) in patients with anterior circulation vessel occlusion stroke. The authors conducted a comprehensive analysis, considering different occlusion sites and their associations with the incidence and severity of ICH, specifically symptomatic (sICH) and non-symptomatic (non-sICH) cases. While the study presents crucial findings, it is essential to discuss its implications and limitations.

    The study's key finding of a 4.5% incidence of sICH after EVT for anterior circulation vessel occlusion stroke is consistent with previous research in this area. The recognition of differences in the frequency and severity of ICH across occlusion sites, particularly in the internal carotid artery (ICA), middle cerebral artery's first segment (M1), and the M2 and beyond, is a significant contribution to our understanding of EVT outcomes. The study suggests that ICA occlusions, despite their lower overall hemorrhage frequency, tend to result in more severe ICH, including intraventricular hemorrhages and space-occupying intracerebral hemorrhages. This observation aligns with prior stud...

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  • The number of clinical events per variable in logistic regression analysis

    Dear Editor,

    I read with interest the paper by Pierot et al [1]. They conducted a prospective study to examine factors of delayed thromboembolic events in 335 patients after coiling of unruptured intracranial aneurysms. The number of delayed TEEs was 8. The adjusted odds ratios (95% confidence intervals) of autosomal dominant polycystic kidney disease and post-procedure aneurysm remnant at procedure completion for delayed TEEs were 27.3 (3.9 to 190.2) and 9.9 (1.0 to 51.3), respectively. They understand the lack of statistical power in the multivariate analysis and did not intend to examine the causal association. I present a comment regarding the number of events in logistic regression analysis.

    The limitation in the total number of events for logistic regression analysis was simulated to improve statistical power [2]. In addition, Peduzzi et al. evaluated the effect of the number of events per variable (EPV) on the outcome in logistic regression analysis [3], concluding that the number of EPV less than 10 has some problems for the prediction of dependent variable. There is an opinion that EPV value less than 10 is also acceptable to evaluate the association by logistic regression analysis [4]. Pierot et al. observed 8 events, which was not appropriate for multivariate analysis even for examining the association instead of prediction in a prospective study. I think that wide ranges of 95% confidence intervals may reflect unstable estimates in a logistic regr...

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  • Middle meningeal artery embolization versus surgical evacuation, How real-world are we?

    Dear Editor,

    We have read with great interest the article entitled “Efficacy and mid-term outcome of middle meningeal artery embolization with or without burr hole evacuation for chronic subdural hematoma compared with burr hole evacuation alone” by Onyinzo, C., et al, published in Journal of NeuroInterventional Surgery (2021).

    The article has compared the Surgical and Endovascular management of (CSDH) in the elderly population who are at high risk to developing (CSDH) due to their co-morbidities and the use of anti-thrombotic agents.
    It is noted that the anti-thrombotic agents were stopped to both management arms. Upfront Middle meningeal artery embolization without stopping the anti-thrombotics, might be a strategy to mitigate the risk of cardio-embolic events.
    In regards to the evaluation of the patients outcome, clinical parameters did not include motor assessment, which is a significant factor to favor a rapid surgical evacuation in these delicate patients.
    As to the radiological follow up, cured (CSDH) were defined in the article with a thickness less than 10 mm. This is debatable as there are a lot of variations exists for this population in regards to brain volume and brain elasticity.
    Finally, we would like to point out the timing of the follow up was not defines for all patients. This need to be harmonized better to a well-defined follow up timeline. Joyce, MD, et al,2 a suggested a time frame of 6 weeks after the treatment...

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  • Action mechanism of the beveled tip aspiration catheter

    We read with great interest the recent paper by Vargas, et al. describing a novel beveled tip aspiration catheter with improved recanalization and patient outcome compared to conventional non-beveled tip catheters in a single-center retrospective study.[1] We want to express our sincere congratulations to the authors on this finding but also want to respectively present our disagreement on the mechanisms explaining the improved performance of the beveled tip catheter as compared to standard catheters.

    The authors conclude that a primary reason for higher rate of complete clot ingestion for the beveled tip catheter relates to the area of the catheter tip. It is widely accepted that ingestion force predicts recanalization efficacy, and this force is proportional to tip area (A) and pressure drop (P). The authors note that the beveled tip leads to an ovalized tip area with a total tip area that is approximately 15% larger than a catheter with an equivalent inner diameter but standard non-beveled tip. They then propose that this 15% increase in tip area leads to a corresponding increase of ingestion force, using the standard F=A*P equation. However, this proposition is flawed. While it is true the total force is larger for the beveled tip catheter than a standard catheter, this total force includes two separate force components that are orthogonal to each other, including the ingestion force component (along the catheter’s length) that corks or ingests the clot and...

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  • Challenges and subtleties in the evaluation of post-procedural cognitive changes

    We congratulate Drs. Srivatsan and colleagues on their paper examining the effects of endovascular coiling of unruptured intracranial aneurysms (UIAs) on cognition using the Montreal Cognitive Assessment (MoCA).1 In particular, we appreciate the efforts made to sample the patients at multiple time points including pre-intervention and at 1-month and 6-months post-intervention. The study found that coiling did not diminish neurocognitive function per the MoCA, with there also being no correlation between follow-up MoCA scores and imaging findings, the overall results being comparable to the authors’ previous paper on MoCA scores following flow diversion for UIAs.2 Intriguingly, the MoCA scores at baseline were on average below the typical cut-off of 26 points, especially given the relatively young population (mean age 55.5 years).

    However, as acknowledged by the authors, the ability of the study to discern post-coiling imaging changes was limited by both the small subset of the population that received follow-up imaging (17 of 33 patients, 51.5%) and the smaller subset that underwent MRI (9 patients, 27.3%).1 Diffusion-weighted imaging (DWI) sequences of MRI are most sensitive to identifying post-procedural ischemic injury following neuro-interventional procedures like coiling.3 DWI lesions occur quite frequently; for example, in the ENACT trial (Evaluating Neuroprotection in Aneurysm Coiling Therapy), 68% of patients had new lesions post-procedure, with an average o...

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  • Technical feasibility and clinical impact.

    After reading the interesting article by Jeon et al, indeed, the first series of cases of revascularization in cerebral infarction, it is important to point out several aspects related to the cancer patient. Cancer is a heterogeneous group of diseases with some points in common related to cellular behavior in the face of cell division controls and their local and systemic effects. Its incidence and prevalence are increasing, and the borders of treatment are changing, as is the disease itself. Patients with active cancer, therefore, should be approached in a multidisciplinary strategy, for the management of their oncological pathology or associated patient comorbidities. Stroke does not escape this strategy, because it does not have the same clinical impact to treat a patient with an oncological disease in early staging compared to one in advanced staging or in disease progression in palliative care and short calculated survival. It is not possible to establish a general rule of treatment in stroke with active cancer for these reasons, and a careful analysis of which primary tumors, their staging or clinical evolution of response to treatment, are necessary to clarify the clinical picture of stroke treatment in the oncological disease context.

  • Regarding: Outcome of patients with large vessel occlusion stroke after first admission in telestroke spoke versus comprehensive stroke center

    Dear Editor,

    Kaminsky et al1 present an interesting study regarding the logistics of patients eligible for endovascular stroke therapy (EVT). They conclude that whether patients with large vessel occlusion (LVO) are first admitted to a hospital with or without this treatment does not affect patient outcome.
    However, there are some difficulties interpreting the main statistical multivariate analyses. Firstly, although there is a clear presentation of how the main multivariate logistic regression analysis is performed, the covariates included in the model are not presented, and the model is not shown in any table. Secondly, the authors have included variables solely based on the strength of their association with the outcome, and not based on the potential of the variable to confound the relationship between the variable of interest (which center the patient is admitted to first), and the outcome. In this setting, it is our opinion that selecting covariates based on an etiological model, that focuses on the variable of interest, and includes covariates based on the potential for confounding, would be the best strategy.2 We disagree with the authors` choice of a prognostic model.
    We urge the authors to provide a table showing the main analysis, or even repeat the main analysis using an etiological approach to model building and variable selection.
    Despite these shortcomings, we commend the authors for undertaking such a relevant clinical study, and we...

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