Endovascular treatment of intracranial arteriovenous malformations using detachable-tip microcatheters and Onyx 18®

Single Centre Initial Experience with the Scepter Mini Balloon Microcatheter

BACKGROUND

The use of balloon microcatheters in interventional neuroradiology is well documented. However, their use is sometimes limited by the small diameter and excessive tortuosity of the vasculature. The Scepter Mini dual-lumen balloon microcatheter (SMBM) (Microvention, Aliso Viejo, CA) has been designed to address these challenges by decreasing the distal catheter profile, allowing distal access to the target vessel.

METHODS

This is a single-centre retrospective analysis of the initial cases performed using the Scepter Mini balloon microcatheter. The targeted conditions were vascular malformations. Patient clinical data, angiographic features of the vascular abnormalities and operation reports were reviewed and the procedural parameters, radiation doses, occlusion rates and complications were assessed.

RESULTS

A total of 15 SMBM were used in 11 cases. In all cases the procedure performed was balloon inflation and antegrade delivery of precipitating hydrophobic injectable liquid (PHIL) (Microvention, Aliso Viejo, CA) for embolisation of a targeted feeding vessel and cranial and spinal vascular malformations. Successful feeding vessel distal access and antegrade liquid embolisation was achieved in 100% of the cases. One of the 11 cases was an emergency procedure. One procedural target vessel rupture, likely due to overinflation, and three minor post-procedure complications were observed.

CONCLUSION

The SMBM represents a significant advance in the treatment of cerebrospinal vascular malformations, allowing balloon catheter access into tortuous and small calibre vessels.

Arm-only combined transarterial and transvenous access for neurointerventional procedures: a double-center retrospective study

OBJECTIVE

This study aims to share our experience with the arm-only combined transarterial and transvenous access approach for neurointerventional procedures and evaluate its efficacy and safety.

METHODS

The arm-only combined transarterial and transvenous access approach was performed using the right/bilateral proximal radial arteries and the right forearm superficial vein system, guided by ultrasonic guidance. Arterial access closure was achieved using a transradial band radial compression device, while manual compression was utilized for venous approach closure.

RESULTS

Thirteen procedures were successfully performed using the arm-only combined transarterial and transvenous access approach, yielding favorable outcomes. The procedures included dural arteriovenous fistula embolization (seven cases), cerebral arteriovenous malformation embolization (four cases), venous sinus thrombosis catheter-directed thrombolysis and intravenous thrombectomy (one case), and cerebral venous sinus stenosis manometry (one case). All procedures were uneventful, allowing patients to ambulate on the same day. At discharge, all patients exhibited modified Rankin scores of 0-2, without any access site or perioperative complications.

CONCLUSION

This double-center study preliminarily demonstrates the feasibility and safety of arm-only combined transarterial and transvenous access applied in neurointerventional procedures for complicated cerebrovascular diseases. The proximal radial artery and forearm superficial vein are recommended as the primary access sites. Unobstructed compression is strongly recommended for radial approach closure.

ADVANCES IN KNOWLEDGE

This study aimed to add evidence and experience on the arm-only combined transarterial and transvenous access, as a new approach, for neurointerventional treatment that required arteriovenous approaches.

Glue, Onyx, Squid or PHIL? Liquid Embolic Agents for the Embolization of Cerebral Arteriovenous Malformations and Dural Arteriovenous Fistulas

Background

Endovascular embolization is an effective treatment option for cerebral arteriovenous malformations (AVMs) and dural arteriovenous fistulas (DAVFs). A variety of liquid embolic agents have been and are currently used for embolization of AVMs and DAVFs. Knowledge of the special properties of the agent which is used is crucial for an effective and safe embolization procedure.

Material and Methods

This article describes the properties and indications of the liquid embolic agents which are currently available: cyanoacrylates (also called glues), and the copolymers Onyx, Squid and PHIL, as well as their respective subtypes.

Results

Cyanoacrylates were the predominantly used agents in the 1980s and 1990s. They are currently still used in specific situations, for example for the occlusion of macro-shunts, for the pressure cooker technique or in cases in which microcatheters are used that are not compatible with dimethyl-sulfoxide. The first broadly used copolymer-based embolic agent Onyx benefits from a large amount of available experience and data, which demonstrated its safety and efficacy in the treatment of cerebral vascular malformations, while its drawbacks include temporary loss of visibility during longer injections and artifacts in cross-sectional imaging. The more recently introduced agents Squid and PHIL aim to overcome these shortcomings and to improve the success rate of endovascular embolization. Novelties of these newer agents with potential advantages include extra-low viscosity versions, more stable visibility, and a lower degree of imaging artifacts.

Conclusion

All the available liquid embolic agents feature specific potential advantages and disadvantages over each other. The choice of the most appropriate embolic agent must be made based on the specific material characteristics of the agent, related to the specific anatomical characteristics of the target pathology.

Treatments of unruptured brain arteriovenous malformations: A systematic review and meta-analysis

BACKGROUND

The best therapeutic option for unruptured brain arteriovenous malformations (bAVMs) patients is disputed.

OBJECTIVE

To assess the occurrence of obliteration and complications of patients with unruptured bAVMs after various treatments.

METHODS

A systematic literature search was performed in PubMed, EMBASE, Web of Science, and so on to identify studies fulfilling predefined inclusion criteria. Baseline, treatment, and outcomes data were extracted for statistical analysis.

RESULTS

We identified 28 eligible studies totaling 5852 patients. The obliteration rates were 98% in microsurgery group (95% confidence interval (CI): 96%-99%, I2 = 74.5%), 97% in surgery group (95%CI: 95%-99%, I2 = 18.3%), 87% in endovascular treatment group (95%CI: 80%-93%, I2 = 0.0%), and 68% in radiosurgery group (95%CI: 66%-69%, I2 = 92.0%). The stroke or death rates were 1% in microsurgery group (95%CI: 0%-2%, I2 = 0.0%), 0% in surgery group (95%CI: 0%-1%, I2 = 0.0%), 4% in endovascular treatment group (95%CI: 0%-8%, I2 = 85.8%), and 3% in radiosurgery group (95%CI: 3%-4%, I2 = 82.9%). In addition, the proportions of hemorrhage were 2% in microsurgery group (95%CI: 1%-4%, I2 = 0.0%), 23% in endovascular treatment group (95%CI: 7%-39%), and 12% in radiosurgery group (95%CI: 12%-13%, I2 = 99.2%). As to neurological deficit, the occurrence was 9% in microsurgery group (95%CI: 6%-11%, I2 = 94.1%), 20% in surgery group (95%CI: 13%-27%, I2 = 0.0%), 14% in endovascular treatment group (95%CI: 10%-18%, I2 = 64.0%), and 8% in radiosurgery group (95%CI: 7%-9%, I2 = 66.6%).

CONCLUSIONS

We found that microsurgery might provide lasting clinical benefits in some unruptured bAVMs patients for its high obliteration rates and low hemorrhage. These findings are helpful to provide a reference basis for neurosurgeons to choose the treatment of patients with unruptured bAVMs.

MRI associated factors of clinical efficacy of embolization in patients with pelvic venous insufficiency

PURPOSE

The purpose of this study was to identify anatomical findings at magnetic resonance imaging (MRI) associated with successful percutaneous embolization in women with pelvic venous insufficiency (PVI).

MATERIAL AND METHODS

Between 2008 and 2018, 168 consecutive women (mean age, 39±9 [SD] years; range: 21-69 years) who underwent percutaneous embolization for PVI confirmed by MRI and phlebography were included. Clinical efficacy of embolization was evaluated by patients' opinion or visual analogue scale. Associated factors of success of embolization were searched by comparing MRI findings in women with successful embolization with those in women with failed embolization using univariate analyses.

RESULTS

The mean follow-up was 36±29 (SD) months (range: 12-138 months). Clinical efficacy of embolization was obtained in 126/168 women (75%), complete symptom improvement in 33/168 women (20%) and significant partial improvement in 92/168 women (55%). No symptom improvement and symptoms exacerbation were observed in 17/168 (10%) and 2/168 (1%) women, respectively. At univariate analysis, right ovarian vein diameter≤7mm and vulvar varicosities were associated with successful embolization (P=0.04 and P=0.01, respectively) and left ovarian vein diameter≤7mm was associated with a complete improvement of symptoms (P=0.03). At multivariate analysis, a small right ovarian vein diameter was the single MRI variable associated with clinical efficacy of embolization (P=0.04).

CONCLUSION

Small ovarian vein diameters on MRI are associated with best clinical efficacy of percutaneous embolization in PVI. Right ovarian vein diameter>7mm should warrant further phlebography to exclude venous insufficiency.

Patient-Specific Blood Flow Analysis for Cerebral Arteriovenous Malformation Based on Digital Subtraction Angiography Images

Real-time digital subtraction angiography (DSA) is capable of revealing the cerebral vascular morphology and blood flow perfusion patterns of arterial venous malformations (AVMs). In this study, we analyze the DSA images of a subject-specific left posterior AVM case and customize a generic electric analog model for cerebral circulation accordingly. The generic model consists of electronic components representing 49 major cerebral arteries and veins, and yields their blood pressure and flow rate profiles. The model was adapted by incorporating the supplying and draining patterns of the AVM to simulate some typical AVM features such as the blood "steal" syndrome, where the flow rate in the left posterior artery increases by almost three times (∼300 ml/min vs 100 ml/min) compared with the healthy case. Meanwhile, the flow rate to the right posterior artery is reduced to ∼30 ml/min from 100 ml/min despite the presence of an autoregulation mechanism in the model. In addition, the blood pressure in the draining veins is increased from 9 to 22 mmHg, and the blood pressure in the feeding arteries is reduced from 85 to 30 mmHg due to the fistula effects of the AVM. In summary, a first DSA-based AVM model has been developed. More subject-specific AVM cases are required to apply the presented in silico model, and in vivo data are used to validate the simulation results.

The Role of Interventional Radiology for the Treatment of Hepatic Metastases from Neuroendocrine Tumor: An Updated Review

Interventional radiology plays an important role in the management of patients with neuroendocrine tumor liver metastasis (NELM). Transarterial embolization (TAE), transarterial chemoembolization (TACE), and selective internal radiation therapy (SIRT) are intra-arterial therapies available for these patients in order to improve symptoms and overall survival. These treatment options are proposed in patients with NELM not responding to systemic therapies and without extrahepatic progression. Currently, available data suggest that TAE should be preferred to TACE in patients with NELM from extrapancreatic origin because of similar efficacy and better patient tolerance. TACE is more effective in patients with pancreatic NELM and SIRT has shown promising results along with good tolerance. However, large randomized controlled trials are still lacking in this setting. Available literature mainly consists in small sample size and retrospective studies with important technical heterogeneity. The purpose of this review is to provide an updated overview of the currently reported endovascular interventional radiology procedures that are used for the treatment of NELM.

First clinical multicenter experience with the new Scepter Mini microballoon catheter

BACKGROUND

Balloon-assisted techniques can improve the endovascular treatment of cerebrospinal vascular malformations. The aim of this study was to report the first clinical multicenter experience with the new Scepter Mini dual-lumen microballoon catheter.

METHODS

Patients with cerebral or spinal vascular malformations treated with the Scepter Mini at seven European neurovascular centers were retrospectively reviewed. Clinical data, angiographic features of the vascular malformations, procedural parameters including the type of application, navigability, technical failures, complications and embolization success were assessed.

RESULTS

The usage of 34 Scepter Mini microballoon catheters in 20 patients was analyzed. Most treated malformations (80.0%) were cerebral arteriovenous malformations. Four different applications were reported: embolization via Scepter Mini (n=23, 67.6%), balloon-occlusion with simultaneous embolization via a second microcatheter (n=3, 8.8%), diagnostic angiography with simultaneous balloon-inflation for flow arrest (n=4, 11.8%), and navigation support (n=4, 11.8%). The mean diameter of the blood vessels in which the Scepter Mini was inflated was 1.9±0.5 mm. The navigability of the Scepter Mini was rated as 'easy' or 'very easy' in 88.2% of cases. Complete occlusion of the malformation was achieved in 60.9% of cases. Technical failures occurred in 4/23 embolization procedures, and all were related to insufficient stability of the balloon within the vessel. No complications related to the Scepter Mini were observed, while unrelated complications occurred in three patients (15.0%).

CONCLUSIONS

The Scepter Mini is a promising new device for balloon-assisted embolization of cerebrospinal vascular malformations via small feeders. Beyond embolization, the Scepter Mini can also be used for other applications, such as superselective flow arrest and navigation support.