The Claw Sign: An angiographic Predictor of Recanalization After Mechanical Thrombectomy for Cerebral Large Vessel Occlusion

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.

"The microcatheter contrast injection technique": A novel technique to detect the proximal end of a thrombus in mechanical thrombectomy

Background: An aspiration catheter needs to attach to a thrombus in order to achieve first-pass recanalization by mechanical thrombectomy (MT) for acute ischemic stroke (AIS), particularly that using a direct aspiration first pass technique. The meniscus sign, which is defined as meniscoid contrast opacification indicating the proximal edge of a thrombus, has been suggested to contribute to successful recanalization. In some cases, the meniscus sign is not detected following an injection of contrast medium through a guiding catheter. To precisely identify the location of a thrombus, we use "the microcatheter contrast injection (MCI) technique," which accurately shows the proximal edge of a thrombus. We herein introduce this novel technique and discuss its efficacy in MT. Methods: In cases without the meniscus sign, a microcatheter was advanced to the distal end of contrast opacification, and contrast medium was injected through the microcatheter to detect the meniscus sign. An aspiration catheter was then advanced to the thrombus indicated by the meniscus sign and slowly withdrawn under aspiration. Results: 29 patients underwent MT for AIS using the MCI technique. Even in cases without the meniscus sign on initial angiography, the MCI technique accurately revealed the proximal edge of the thrombus. Moreover, middle cerebral artery occlusion due to atherosclerotic stenosis and displacement of the aspiration catheter and thrombus axis were detected using this technique. Conclusions: The MCI technique may effectively reveal the exact site of a thrombus and increase the success rate of first-pass recanalization.

Modified treatment in cerebral ischemia 1 versus modified treatment in cerebral ischemia 0 before endovascular stroke treatment in middle cerebral artery’s M1-occlusion: Predictor for revascularization success and outcome?

Background

Little is known about the implications for revascularization success of target vessel occlusions (TVOs) with persisting antegrade perfusion before initiation of endovascular stroke treatment (EST) (modified treatment in cerebral ischemia (mTICI 1)) compared to a complete occlusion (mTICI 0). Here, we compared these two states of TVO.

Methods

Retrospective, single-center analysis of patients treated for M1-segment middle cerebral artery (MCA) occlusion with EST from January 2015 until May 2020 in a tertiary stroke center. Primary study endpoint was successful recanalization (mTICI 2c-3) after one thrombectomy attempt. Secondary endpoints were clinical outcome (modified Rankin Scale (mRS) 90 days after stroke onset), complication rate, and rate of underlying atherosclerotic disease. The two study groups were compared in univariate analysis including patient characteristics and procedural details.

Results

In this study, 422/581 patients (72.6%) presented with complete M1-occlusion compared to 159/581 (27.4%) with incomplete M1-occlusion. Neither did the recanalization success rate differ between the study groups nor the rate of complications (mTICI 0: 2.4%, mTICI 1: 0.6%, p = 0.304) or underlying atherosclerotic disease. Patients with incomplete initial occlusion showed a lower mRS at discharge (median interquartile range (IQR) mTICI 0: 4 (3–5) vs. mTICI 1: 3 (2–6), p = 0.014), but a comparable mRS 90 days after stroke onset (mTICI 0: 3 (2–6) vs. mTICI 1: 4 (2–6), p = 0.479).

Conclusion

Complete M1-occlusions (mTICI 0) and incomplete occlusions (mTICI 1) show the same recanalization success, comparable complication rate, and clinical outcome as well as the same rate of underlying atherosclerotic disease. Thus, incomplete M1-occlusions do not allow for an individualized interventional approach.

Mechanical thrombectomy for acute fetal posterior cerebral artery occlusion with a hidden unruptured cerebral aneurysm: illustrative case

BACKGROUND

Fetal posterior cerebral artery occlusion is rare and often presents with severe neurological symptoms. Although acute recanalization therapy is commonly used for cerebral vessel occlusion, unruptured cerebral aneurysms can be hidden distal to the occluded vessels.

OBSERVATIONS

An 87-year-old man presented with consciousness disturbance and right hemiparesis. The authors diagnosed left fetal posterior cerebral artery occlusion and performed mechanical thrombectomy. A stent retriever was deployed from the middle cerebral artery M1 segment across the mural thrombus of the internal carotid artery. After the first pass, the fetal posterior cerebral artery remained occluded, with confirmation of a contrast effect around the thrombus. Because the anatomical course of the fetal posterior cerebral artery was unidentified, the procedure was stopped. At 1-week recovery, magnetic resonance imaging revealed complete recanalization and a fetal posterior cerebral artery aneurysm hidden within the occluded site. Blood flow was directed to the aneurysm, and the thrombus within the aneurysm simultaneously occluded the fetal posterior cerebral artery.

LESSONS

To avoid critical complications following mechanical thrombectomy for fetal posterior cerebral artery occlusion, hidden aneurysms should be suspected when a “fried egg–like” contrast effect is observed around the thrombus.

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 Meniscus Sign Is Associated With Thrombus Permeability and Choice of Mechanical Thrombectomy Technique in Acute Middle Cerebral Artery Occlusion

Background and Purpose

The method of mechanical thrombectomy (MT) is related to vascular anatomy and stroke etiology. Meniscus sign and thrombus permeability as imaging markers may be instructive for the selection of MT. This study aims to clarify the relationship among meniscus sign, thrombus permeability, and choice of MT in patients with acute middle cerebral artery occlusion.

Materials and Methods

A total of 111 patients with acute middle cerebral artery occlusion (MCAO) who underwent MT were retrospectively analyzed. Clot meniscus sign was defined as the appearance of meniscoid/edge-like or single- or double-wall contrast channels besides or around insular blood clots. The radiographic, clinical, and surgical data of patients with MCAO with or without meniscus sign were compared.

Results

The meniscus sign positive group (n = 26) has higher thrombus permeability (HUs) (26.92 ± 9.69 vs. 22.84 ± 7.88, p = 0.031) than those without it. Shorter puncture-to-recanalization (P2R) time (65.5 vs. 88, p = 0.012), higher complete recanalization rate (85.71 vs. 33.33%, p < 0.01), and better clinical outcome (p < 0.01) were obtained by selecting contact aspiration (CA) over stent retriever (SR) in patients with positive meniscus sign. In patients with negative meniscus sign, there was no significant difference in clinical outcome after receiving CA or SR.

Conclusion

Patients with MCAO with positive meniscus sign have higher thrombus permeability and are more suitable for CA to acquire better clinical outcomes.

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.

Clot Meniscus Sign: An Angiographic Clue for Choosing between Stent Retriever and Contact Aspiration in Acute Basilar Artery Occlusion

BACKGROUND AND PURPOSE

The efficacy of mechanical thrombectomy methods may differ depending on the characteristics of the occlusion. The purpose of this study was to compare the recanalization efficacy and treatment outcome of a stent retriever versus contact aspiration in patients with acute basilar artery occlusion according to the angiographic characteristics of the occlusion.

MATERIALS AND METHODS

One hundred sixty-one patients with acute basilar artery occlusion who underwent mechanical thrombectomy were retrospectively analyzed. A stent retriever was compared with contact aspiration thrombectomy according to the clot meniscus sign, defined as a meniscoid/tram-track-like sidewall contrast opacification of the thrombus. A propensity score matching analysis was performed. Clinical/angiographic characteristics and treatment and clinical outcomes were compared.

RESULTS

Overall, a stent retriever (n = 118) and contact aspiration (n = 43) did not show significant differences in the successful recanalization (82.2% versus 86.0%) and good clinical outcome rates (32.2% versus 39.5%). In patients with the positive meniscus sign, contact aspiration was associated with shorter procedural time (44 versus 26 minutes, P = .018), a lower number of passes (2 versus 1, P = .041), a higher complete recanalization rate (58.8% versus 85.7%, P = .021), and a higher rate of first-pass effect (27.9% versus 53.6%, P = .031) compared with a stent retriever. After propensity score matching, contact aspiration was associated with higher complete recanalization rates (59.3% versus 85.7%, P = .033). No significant differences in the outcomes were noted between a stent retriever and contact aspiration in patients negative for the meniscus sign.

CONCLUSIONS

The efficacy of the mechanical thrombectomy techniques may differ according to the angiographic characteristics of occlusion in patients with basilar artery occlusion. Contact aspiration may be more effective in terms of recanalization compared with a stent retriever in patients with the clot meniscus sign.

Significance of angiographic clot meniscus sign in mechanical thrombectomy of basilar artery stroke

Introduction

The relationship between the occlusive clot morphology and the efficacy of mechanical thrombectomy (MT) in basilar artery occlusion (BAO) is not well known. Our aim was to evaluate the clinical significance of the clot meniscus sign in patients with acute BAO.

Methods

89 patients with acute BAO who underwent MT were retrospectively analyzed. The clot meniscus sign was defined as meniscoid/tram-track like antegrade side-wall contrast opacification of the thrombus. Patients were assigned to two groups based on the presence of the clot meniscus sign. The treatment and clinical outcomes were compared.

Results

The clot meniscus sign was diagnosed in 62.9% (53/89) of the patients. The meniscus sign (+) group showed a shorter procedure time (55 vs 85 min; p=0.045), higher rate of successful recanalization (89.3% vs 63.6%, p=0.004), higher incidence of first pass effect (32.1% vs 6.1%, p=0.004), and lower number of passes (2 vs 3; p=0.042) when compared with the meniscus sign (−) group. The procedure time (OR 0.972, 95% CI 0.962 to 0.992; p=0.003) and clot meniscus sign (OR 7.920, 95% CI 1.769 to 35.452; p=0.007) were independent predictors of successful recanalization.

Conclusion

The clot meniscus sign is related to high first pass effect and short procedure time and is a reliable predictor of successful recanalization in patients with acute BAO.