Endovascular Thrombectomy Outcomes In Stroke: The Truth About HT Or ICH Risk
Overview
The study investigated the occurrence of hemorrhagic transformation (HT) and symptomatic intracranial hemorrhage (sICH) following endovascular thrombectomy (EVT) in patients with acute ischemic stroke (AIS). Through a retrospective analysis of 118 patients who underwent EVT for acute anterior circulation stroke, the study aimed to identify clinical and imaging predictors of HT and sICH, subsequently constructing a risk prediction system based on the findings.
The results revealed that HT occurred in 46.6% of patients, while sICH occurred in 15.3%. Multivariate logistic regression analysis identified several factors associated with HT and sICH. These included Alberta Stroke Program Early CT Score (ASPECTS), collateral status, relative cerebral blood flow (CBF) ratio, and blood glucose levels on admission. Collateral circulation, ASPECTS, and blood glucose levels on admission were highlighted as independent predictors for sICH as well.
Based on these findings, a predictive model for HT after EVT was established, demonstrating high sensitivity and specificity, along with a favorable area under the curve (AUC). The model incorporated factors such as collateral status, ASPECTS, relative CBF ratio, and blood glucose levels, offering valuable insights into the likelihood of HT post-EVT.
In conclusion, collateral status, ASPECTS, relative CBF ratio, and blood glucose levels on admission emerged as significant predictors for HT in AIS patients undergoing EVT. Additionally, collateral status, ASPECTS, and blood glucose levels were identified as predictors for sICH. The predictive model devised from these predictors exhibited robust diagnostic value, providing clinicians with a tool to assess the risk of HT following EVT and guide appropriate management strategies.
Introduction
This study delves into the critical issue of hemorrhagic transformation (HT), a frequent complication observed after endovascular therapy (EVT) for acute ischemic stroke (AIS). Despite the documented success of EVT in enhancing vascular recanalization and widening the therapeutic time window, HT, especially symptomatic intracranial hemorrhage (sICH), persists as a significant challenge, substantially undermining the benefits of EVT and leading to unfavorable long-term consequences.
While prior investigations have primarily concentrated on identifying risk factors associated with HT following intravenous thrombolysis, such as infarct volume, collateral circulation status, and comorbidities like diabetes and hypertension, there exists a noticeable gap in comprehensively understanding the predictors of HT in the context of EVT. This study aims to bridge this gap by conducting an exhaustive analysis that encompasses both clinical and imaging indicators, with a specific focus on magnetic resonance imaging (MRI) findings.
Through an exploration of a diverse range of potential predictors, this study endeavors to enrich our comprehension of HT and sICH in patients undergoing EVT for acute anterior circulation stroke. The insights gleaned from this research hold promise in refining our interventions and devising more effective strategies to mitigate risk, thereby fostering improved outcomes for individuals undergoing EVT for AIS.
Method
The study aimed to delve into the intricacies of endovascular treatment (EVT) for anterior circulation ischemic stroke by conducting a meticulous analysis of 118 patients over a three-year period. This cohort comprised 81 male and 37 female individuals, carefully selected based on stringent inclusion criteria including age, stroke etiology, and time window for intervention. EVT procedures, performed within 24 hours post-stroke onset, predominantly utilized solitaire stent retrievers via the Solumbra or Swim technique, with a contingency plan involving the direct aspiration first-pass technique if initial recanalization attempts failed. This standardized approach ensured consistency and adherence to established guidelines for acute ischemic stroke management.
Post-procedural assessment was conducted through head CT scans, with particular emphasis on detecting hemorrhagic transformation (HT), a potential complication of reperfusion therapy. The identification of HT, classified into various subtypes based on specific radiographic features, allowed for nuanced characterization and informed clinical decision-making regarding patient management. Of particular interest was the distinction between asymptomatic and symptomatic intracranial hemorrhage (sICH), with the latter carrying significant implications for patient prognosis and treatment strategies.
Preprocedural imaging evaluation encompassed a comprehensive array of MRI sequences, providing insights into various aspects of ischemic injury and collateral circulation. Advanced imaging techniques such as diffusion-weighted imaging (DWI), arterial spin labeling (ASL), and 3D time-of-flight magnetic resonance angiography (TOF-MRA) facilitated the assessment of infarct size, cerebral blood flow, and collateral perfusion patterns. Moreover, the meticulous analysis of imaging parameters, including ASPECTS score, ADC and CBF ratios, and DWI-FLAIR mismatch, offered valuable prognostic information and guided therapeutic decision-making.
The study’s robust methodology, encompassing both pre- and post-procedural imaging assessments, underscores the multidimensional nature of ischemic stroke evaluation and management. By leveraging state-of-the-art imaging modalities and meticulous radiographic analysis, the study aimed to enhance our understanding of ischemic stroke pathophysiology and optimize treatment strategies to improve patient outcomes. Additionally, the collaborative efforts of multidisciplinary teams, including neurointerventionalists and neuroradiologists, highlight the importance of a comprehensive and integrated approach to ischemic stroke care.
Statistical Analysis
The statistical analysis of the data in this study was conducted using SPSS (version 22.0) software, a widely recognized tool for data analysis. Initial univariate analysis was performed on all clinical and imaging indicators, employing appropriate statistical methods based on the data type and distribution. Subsequently, multivariate analysis was executed utilizing a binary logistic regression model.
In the multivariate analysis, variables that demonstrated significance (p<.05) in the univariate analysis were included, with only predictive factors exhibiting statistical significance (p<.05) being retained in the final model. These factors, delineated by regression coefficients, were then organized into a risk factor prediction system.
To assess the predictive efficacy of the model, receiver-operating characteristic (ROC) analysis was employed. This method evaluates the performance of predictive models by examining the relationship between sensitivity and specificity across different threshold values.
Overall, this rigorous statistical approach enabled the identification of significant predictive factors and the development of a robust risk factor prediction system, providing valuable insights into the study’s objectives.
Result
The study involved 118 patients (81 males, 37 females) with an average age of 62.52±13.65, examining the incidence of hemorrhagic transformation (HT) following endovascular treatment (EVT) for stroke. Of these patients, 46.6% had HT, including various types such as hemorrhagic infarction (HI) and subarachnoid hemorrhage. Multivariate logistic regression analysis revealed that higher blood glucose levels upon admission were associated with an increased risk of HT, while better collateral circulation, higher DWI-ASPECTS (Diffusion-Weighted Imaging Alberta Stroke Program Early CT Score), and higher relative cerebral blood flow (CBF) ratio were protective factors.
Furthermore, univariate and multivariate regression analyses were conducted to identify predictors for symptomatic intracerebral hemorrhage (sICH). Blood glucose levels upon admission, NIHSS score, diabetes, infarct area, DWI-ASPECTS, relative CBF ratio, collateral circulation, and integrity of the circle of Willis were significantly associated with sICH. In the multivariate analysis, blood glucose levels upon admission, collateral circulation, and DWI-ASPECTS emerged as predictors for sICH.
To enhance predictive accuracy, collateral circulation, DWI-ASPECTS, relative CBF ratio, and blood glucose levels upon admission were integrated into a risk prediction system. This model exhibited high sensitivity (90.9%) and specificity (79.4%), with an area under the curve (AUC) of 90.0%, outperforming individual predictors alone.
In summary, the study underscores the importance of various clinical and imaging factors in predicting HT and sICH following EVT for stroke. The developed risk prediction system offers a valuable tool for clinicians in assessing hemorrhagic complications and optimizing patient outcomes.
Conclusion
This study investigated the incidence of hemorrhagic transformation (HT) and symptomatic intracranial hemorrhage (sICH) following endovascular thrombectomy (EVT) in patients with acute anterior circulation ischemic stroke. The findings revealed higher incidences of HT (46.6%) and sICH (15.3%) compared to previous randomized controlled trials, possibly attributed to a higher prevalence of intracranial atherosclerotic stenosis in Asian patients and a broader time window for EVT initiation (up to 24 hours post-stroke onset) as recommended by recent guidelines.
The study identified several predictive factors for HT and sICH post-EVT. Decreased Diffusion-Weighted Imaging Alberta Stroke Program Early CT Score (DWI-ASPECTS), indicating more extensive ischemic damage, was associated with higher rates of HT and sICH. Additionally, reduced relative cerebral blood flow (CBF) ratio, assessed via arterial spin labeling (ASL), was linked to increased HT risk, suggesting that compromised perfusion contributes to hemorrhagic complications post-EVT.
Poor collateral circulation, evaluated through digital subtraction angiography (DSA), emerged as a significant independent risk factor for HT and sICH. While DSA provided comprehensive collateral status assessment, noninvasive methods like 3D-time-of-flight magnetic resonance angiography (3D-TOF MRA) were less effective, particularly in identifying secondary or tertiary collaterals.
Incomplete circle of Willis, observed in patients with anterior circulation infarction, was associated with higher HT incidence, although it didn’t retain significance in multivariate analysis. Higher baseline blood glucose levels were also linked to increased HT risk, likely due to exacerbated vascular injury and blood-brain barrier disruption.
A risk prediction model incorporating imaging features and clinical indicators demonstrated good performance in assessing HT risk post-EVT, with an area under the curve (AUC) of 90.0%. However, the study had limitations, including its retrospective nature, relatively small sample size, and focus on short-term outcomes without long-term follow-up.
In conclusion, while EVT improves recanalization rates in acute ischemic stroke, it poses a risk of HT, particularly in patients with poor collateral circulation and higher baseline blood glucose levels. Developing robust risk prediction models and further research with larger datasets and multimodal imaging assessments are essential for optimizing patient selection and minimizing adverse events post-EVT.
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