Angiographic Baseline Proximal Thrombus Appearance of M1/M2 Occlusions in Mechanical Thrombectomy

Clot patterns determined by DSA and CTA can help predict intracranial atherosclerotic stenosis in acute ischemic stroke patients

Background

This study examines whether clot patterns at large artery occlusion sites, as observed using digital subtraction angiography (DSA) and computed tomography angiography (CTA), can reliably indicate intracranial atherosclerotic stenosis (ICAS) in acute ischemic stroke (AIS) patients.

Methods

We conducted a retrospective analysis of patients treated with stent retriever thrombectomy for intracranial occlusions at our institute since 2017, with follow-up assessments conducted at 3 months. The patients were grouped based on the initial angiography clot topographies (i.e., cut-off or tapered signs). We assessed the potential of these topographies in predicting ICAS, including a clinical outcome analysis based on clot pattern, age, Trial of Org 10172 in Acute Stroke Treatment (TOAST) classification, and onset-to-door time.

Results

Among 131 patients (with a mean age of 66.6 years), the clot pattern emerged as a significant predictor of ICAS. The DSA-based model had a predictive area under the curve (AUC) of 0.745, with 55.1% sensitivity and 94.0% specificity. A multivariate model including age, onset-to-door time, TOAST classification as large artery atherosclerosis (LAA), and the presence of the tapered sign in clot patterns had an AUC of 0.916. In patients over 65 years of age with an onset-to-door time of >5 h and exhibiting a tapered sign in the clot pattern, the AUC reached 0.897. The predictive ability of the tapered sign was similar in DSA and CTA, showing 73.4% agreement between modalities.

Conclusion

The clot pattern with the tapered sign as observed using DSA is significantly associated with ICAS. Incorporating this clot pattern with age, TOAST classification as LAA, and onset-to-door time enhances the prediction of ICAS. The clot pattern identified by CTA is also a reliable predictor, highlighting the importance of assessing clot patterns in ICAS identification.

Endovascular Detection of Catheter-Thrombus Contact by Vacuum Excitation

OBJECTIVE

The objective of this work is to introduce and demonstrate the effectiveness of a novel sensing modality for contact detection between an off-the-shelf aspiration catheter and a thrombus.

METHODS

A custom robotic actuator with a pressure sensor was used to generate an oscillatory vacuum excitation and sense the pressure inside the extracorporeal portion of the catheter. Vacuum pressure profiles and robotic motion data were used to train a support vector machine (SVM) classification model to detect contact between the aspiration catheter tip and a mock thrombus. Validation consisted of benchtop accuracy verification, as well as user study comparison to the current standard of angiographic presentation.

RESULTS

Benchtop accuracy of the sensing modality was shown to be 99.67%. The user study demonstrated statistically significant improvement in identifying catheter-thrombus contact compared to the current standard. The odds ratio of successful detection of clot contact was 2.86 (p = 0.03) when using the proposed sensory method compared to without it.

CONCLUSION

The results of this work indicate that the proposed sensing modality can offer intraoperative feedback to interventionalists that can improve their ability to detect contact between the distal tip of a catheter and a thrombus.

SIGNIFICANCE

By offering a relatively low-cost technology that affords off-the-shelf aspiration catheters as clot-detecting sensors, interventionalists can improve the first-pass effect of the mechanical thrombectomy procedure while reducing procedural times and mental burden.

Angiographic demonstration of a cutoff sign as an unfavorable prognostic indicator for patients with acute ischemic stroke undergoing mechanical thrombectomy

OBJECTIVES

The aim was to investigate whether the angiographic demonstration of a cutoff sign on the initial angiogram could predict recanalization and prognosis in acute ischemic stroke patients treated by endovascular thrombectomy.

METHODS

The angiographic and clinical data of patients who underwent endovascular treatment from October 2018 to April 2023 were retrospectively reviewed. The pretreatment angiographic appearance of the thrombus's proximal part was assessed and classified as either the cutoff sign (+) or (-). Patients' baseline characteristics and angiographic and clinical outcomes between the two groups were analyzed using propensity score matching. Then, the two commonly used techniques, stent retrieval and contact aspiration, were compared in terms of successful reperfusion and clinical outcome in patients with the cutoff sign.

RESULTS

The cutoff sign was observed in 77 (36.2%) of 213 patients. Patients with the cutoff sign were younger and were less likely to have involvement of the anterior circulation. Compared with the cutoff sign (-) group, the cutoff sign (+) group had a significantly longer procedure time (103 versus 80 min, P =0.002) and a lower percentage of 3-month good functional outcomes (18.2% versus 36%, P =0.006). After propensity score matching, the procedure time (100 versus 75 min, P =0.002) and the 3-month good outcome (19.2% versus 41.4%, P =0.004) remained significantly different. No significant differences were observed in the radiological (OR 0.758, 95% CI 0.157 to 3.658; P =0.730) and clinical (OR 0.747, 95% CI 0.147 to 3.787; P =0.725) outcomes between the two techniques.

CONCLUSIONS

The cutoff sign might be an unfavorable prognostic indicator in patients undergoing mechanical thrombectomy, and the efficacy of mechanical thrombectomy techniques does not differ in patients positive for the cutoff sign.

Meniscus Sign in Patients with Anterior Circulation Large Vessel Occlusion Stroke does not Predict Outcome

PURPOSE

The angiographic appearance of the occlusion site was suggested to influence outcomes of stroke patients with large vessel occlusion (LVO) who undergo endovascular treatment (EVT). We aimed to study the impact of the meniscus sign (MS) on outcomes of stroke patients with anterior circulation LVO.

METHODS

Based on two prospective registries of acute ischemic stroke, we selected patients with carotid‑T, M1 or M2 occlusion who underwent EVT. Clinical characteristics and outcomes were collected from the registries or from individual records. Two independent observers blinded to outcomes assessed the presence of MS in digital subtraction angiography before thrombectomy. Angiographic and clinical outcomes of patients with and without MS were compared.

RESULTS

We included 903 patients, with median age of 78 years, 59.8% were male, median baseline NIHSS was 14 and 39.5% received intravenous thrombolysis. Patients with MS (n = 170, 18.8%) were more frequently female, presented with higher NIHSS scores and more frequently underwent intravenous thrombolysis. Presence of MS was significantly associated with cardioembolic etiology. Successful reperfusion, number of passes, first pass effect, procedural time, symptomatic intracerebral hemorrhage, in-hospital mortality and favorable 3‑month functional outcome were similar in the groups of patients with and without MS. In the multivariable analyses, MS was not associated with successful reperfusion (odds ratio, OR = 1.08, 95% confidence interval, CI = 0.76-1.55), first pass effect (OR = 0.96, 95%CI = 0.48-1.92) or favorable 3‑month outcome (OR = 1.40, 95%CI = 0.88-2.24).

CONCLUSION

The presence of MS in acute ischemic stroke patients with anterior circulation large vessel occlusion who undergo EVT does not appear to influence angiographic or clinical outcomes.

A Clinical Prediction Model for Patients with Acute Large Vessel Occlusion Due to Underlying Intracranial Atherosclerotic Stenosis

Background

Acute large vessel occlusion due to underlying intracranial atherosclerotic stenosis (ICAS-LVO) increases the difficulty of revascularization, resulting in frequent re-occlusion. The establishment of its pathogenesis before endovascular treatment (EVT) is beneficial for patients. We aimed at developing and validating a clinical prediction model for ICAS-LVO patients before EVT.

Methods

Patients with acute large vessel occlusion at Jining No. 1 People’s Hospital from January 2019 to September 2021 were retrospectively included as the training cohort. The 70 patients who met the inclusion and exclusion criteria were included in the validation cohort (October 2021 to May 2022). Demographics, onset form, medical history, digital subtraction angiography (DSA) imaging data, and laboratory test data were collected. Preprocedural parameters for the ICAS-LVO risk prediction model were established by stepwise logistic regression controlling for the confounding effects. Then, we constructed a nomogram model and evaluated its performance via the Hosmer-Lemeshow goodness-of-fit test, area under the ROC curve (AUC) analysis.

Results

The 231 acute LVO patients were included in the final analysis, 74 (32.3%) patients were ICAS-LVO. A preoperative diagnosis prediction model consisting of five predictors for ICAS-LVO, including fluctuating symptoms, NIHSS < 16, atrial fibrillation, tapered sign, and ASITN/SIR score ≥ 2. The model depicted an acceptable calibration (Hosmer-Lemeshow test, p = 0.451) and good discrimination (AUC, 0.941; 95% confidence interval, 0.910–0.971). The optimal cut-off value for the ICAS-LVO scale was 2 points, with 86.5% sensitivity, 91.1% specificity, and 90.5% accuracy. In the validation cohort, the discriminative ability was promising with an AUC value of 0.897, implying a good predictive performance.

Conclusion

The established ICAS-LVO scale, which is composed of five predictors: fluctuating symptoms, NIHSS < 16, atrial fibrillation, tapered sign, and ASITN/SIR score ≥ 2, has a good predictive value for ICAS-LVO in Chinese populations.

The claw sign predicts first-pass effect in mechanical thrombectomy for cerebral large vessel occlusion in the anterior circulation

Background:

Mechanical thrombectomy (MT) is an effective treatment for acute cerebral large vessel occlusion (LVO). Complete recanalization of vessels in a single procedure is defined as the first-pass effect (FPE) and is associated with good prognosis. In this study, angiographic clot protruding sign termed the “claw sign,” was examined as candidate preoperative imaging factor for predicting the FPE.

Methods:

We retrospectively analyzed data from 91 consecutive patients treated for acute LVO in the anterior circulation by MT between January 2014 and December 2019. The claw sign was defined as a thrombus that protruded proximally by more than half of the diameter of the parent artery. Radiological findings such as claw sign, clinical and etiological features, and outcomes were compared between groups with and without successful FPE. Multivariate analysis was conducted to evaluate perioperative factors associated with FPE.

Results:

FPE was achieved in 26 of 91 (28.6%) patients and the claw sign was observed in 34 of 91 (37.4%) patients. The claw sign was significantly more frequent in the successful FPE group than in the failed FPE group (53.8% vs. 30.8%; P = 0.040). After the multivariate analysis, the claw sign was the only pretreatment parameter that could predict FPE (odds ratio, 2.67; 95% confidence interval, 1.01–7.06; P = 0.047).

Conclusion:

The claw sign is an angiographic imaging factor that might predict FPE after MT for anterior circulation acute ischemic stroke.

Clot Composition Analysis as a Diagnostic Tool to Gain Insight into Ischemic Stroke Etiology: A Systematic Review

Mechanical thrombectomy renders the occluding clot available for analysis. Insights into thrombus composition could help establish the stroke cause. We aimed to investigate the value of clot composition analysis as a complementary diagnostic tool in determining the etiology of large vessel occlusion (LVO) ischemic strokes (International Prospective Register of Systematic Reviews [PROSPERO] registration # CRD42020199436). Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we ran searches on Medline (using the PubMed interface) and Web of Science for studies reporting analyses of thrombi retrieved from LVO stroke patients subjected to mechanical thrombectomy (January 1, 2006 to September 21, 2020). The PubMed search was updated weekly up to February 22, 2021. Reference lists of included studies and relevant reviews were hand-searched. From 1,714 identified studies, 134 eligible studies (97 cohort studies, 31 case reports, and six case series) were included in the qualitative synthesis. Physical, histopathological, biological, and microbiological analyses provided information about the gross appearance, mechanical properties, structure, and composition of the thrombi. There were non-unanimous associations of thrombus size, structure, and composition (mainly proportions of fibrin and blood formed elements) with the Trial of Org 10172 in Acute Stroke Treatment (TOAST) etiology and underlying pathologies, and similarities between cryptogenic thrombi and those of known TOAST etiology. Individual thrombus analysis contributed to the diagnosis, mainly in atypical cases. Although cohort studies report an abundance of quantitative rates of main thrombus components, a definite clot signature for accurate diagnosis of stroke etiology is still lacking. Nevertheless, the qualitative examination of the embolus remains an invaluable tool for diagnosing individual cases, particularly regarding atypical stroke causes.

Intraprocedural Angiographic Signs Observed During Endovascular Thrombectomy in Patients With Acute Ischemic Stroke: A Systematic Review

OBJECTIVE

In the real-world practice of endovascular thrombectomy (EVT) for acute ischemic stroke (AIS), the analysis of intraprocedural angiographic signs (IPASs) still challenges neurointerventionists. This review provides insights into the significance of these subtle changes for predicting underlying etiology, technical feasibility, and patient prognosis, thus promoting the potential real-time application of these signs.

METHODS

A systematic literature search was conducted using PubMed, Ovid Medline/Embase, and Cochrane. The search focused on studies published between January 1995 and August 2020 that reported findings related to intraprocedural angiographic manifestations in endovascular recanalization therapy for AIS.

RESULTS

We identified 12 IPASs in 22 studies involving 1,683 patients. The IPASs were assigned into 3 subsets according to their clinical meanings.

CONCLUSION

The systematic analysis of IPAS in clinical trials and practice will lead to a better understanding of treatment effects, responses, and mechanisms during EVT. Studies of larger cohorts using more robust statistical methods are needed.