A review of technological innovations leading to modern endovascular brain aneurysm treatment

Dynamic Rigidity Control for Supportive Sheaths in Endovascular Procedures

Endovascular procedures require sheaths with contradictory mechanical properties: flexibility for navigation through tortuous vessels, yet rigidity for device delivery. Current approaches rely on multiple device exchanges, increasing procedural time, and complication risks. Here we present a novel endovascular sheath design scheme with dynamically controllable flexural rigidity along its entire length. The device incorporates axially aligned metal string arrays between inner and outer lumens, enabling transition between flexible and rigid states through suction actuation. Three-point bend testing demonstrated that actuation increases flexural rigidity from the range associated with diagnostic catheters to that associated with support sheaths. In simulated contralateral access procedures, the device reduced access time to 1/3 of the time required when using conventional approaches. in vivo porcine studies validated the sheath's ability to navigate tortuous anatomy in its flexible state and successfully support advancement of increasingly rigid therapeutic devices when actuated. Technology enables single-sheath delivery of treatment, potentially reducing procedural complexity, decreasing complication rates, and improving patient outcomes across various endovascular interventions. This design represents a promising approach to combining catheter and sheath design that benefits both peripheral and neurovascular procedures.

Complex Anatomy, Advanced Techniques: Microsurgical Clipping of a Ruptured Hypophyseal Artery Aneurysm

Background: Ruptured intracranial aneurysms remain the subject of debate in their management, but the management of lesions located at high-risk locations, such as the hypophyseal artery, continue to prove to be a challenge in anatomical orientation and proximity to vascular structures. While endovascular therapies have changed the treatment paradigms, microsurgical clipping is the gold standard for wide-necked aneurysms for which endovascular techniques may be suboptimal. The successful treatment of a ruptured hypophyseal artery aneurysm in an elderly patient is described in this report, which highlights the importance of advanced imaging, careful technique, and new understanding of personalized aneurysm management. Methods: An 82-year-old woman was admitted with a thunderclap headache, alteration of consciousness and meningeal signs, suggestive of subarachnoid hemorrhage (SAH). A non-contrast computed tomography (CT) and digital subtraction angiography (DSA) confirmed a saccular 12 × 10 mm aneurysm with a broad 3.13 mm neck arising from the hypophyseal artery. The location and morphology of the aneurysm required microsurgical clipping, which was performed through a right pterional craniotomy. Results: Correct clip placement, complete exclusion of the aneurysm, and resorption of the subarachnoid blood were both observed on postoperative imaging. The neurological examination was completely normal, with no complications. Follow-up imaging at three months demonstrated stable, marked cerebral atrophy with compensatory ventricular enlargement without evidence of recurrence. Conclusions: This case illustrates the important role of micro-surgical clipping in anatomically complex aneurysms and its sustainable outcome and accuracy in cases where endovascular practices would have limitations. Advanced imaging, like three-dimensional DSA and intraoperative tools, have revolutionized precision surgery, allowing achievement of optimal outcomes, even for more-complicated cases. With an evolving, dynamic field and exciting new technologies coming to the fore-such as artificial intelligence to predict rupture risk and augmented reality navigation-decision-making and treatment of complex aneurysms will be optimized along secure pathways towards tailored, high-resolution treatment in the sense of personalized and yet high-precision care.

Design of thermally programmable 3D shape memory polymer-based devices tailored for endovascular treatment of intracranial aneurysms

Despite recent technological advancements in endovascular embolization devices for treating intracranial aneurysms (ICAs), incomplete occlusion and aneurysm recanalization remain critical challenges. Shape memory polymer (SMP)-based devices, which can be manufactured and tailored to patient-specific aneurysm geometries, possess the potential to overcome the suboptimal treatment outcome of the gold standard: endovascular coiling. In this work, we propose a highly porous patient-specific SMP embolic device fabricated via 3D printing to optimize aneurysm occlusion, and thus, improve the long-term efficacy of endovascular treatment. To facilitate device deployment at the aneurysm via Joule-heating, we introduce a stable, homogeneous coating of poly-pyrrole (PPy) to enhance the electrical conductivity in the SMP material. Using an in-house pulse width modulation circuit, we induced Joule-heating and characterized the shape recovery of the PPy-coated SMP embolic devices. We found that the employed PPy coating enables enhanced electrical and thermal conductivity while only slightly altering the glass transition temperature of the SMP material. Additionally, from a series of parametric studies, we identified the combination of catalyst concentration and pyrrole polymerization time that yielded the shape recovery properties ideal for ICA endovascular therapy. Collectively, these findings highlight a promising material coating for a future coil-free, personalized shape memory polymer (SMP) embolic device, designed to achieve long-lasting, complete occlusion of aneurysms.

Energy barriers govern catheter herniation during endovascular procedures: a 2.5D vascular flow model analysis

Endovascular procedures rely on navigating guidewires, catheters and other devices through tortuous vasculature to treat disease. A critical challenge in these procedures is catheter herniation, in which the device deviates from its intended path, often irrecoverably. To elucidate the mechanics of herniation, we developed a physical flow model of the aortic arch that enables direct measurement of device curvature during experimentally simulated neuroendovascular procedures conducted from an upper arterial access. Combined with measurements of initial, unstressed device shapes and flexural rigidities, the method enables the experimental estimation of the device bending energies during these simulated procedures. Characteristic energy profiles revealed distinct stages in both herniation and successful navigation, governed by the interplay between device properties and vascular anatomy. A deterministic progression from successful navigation to herniation was identified, with catheter systems following paths determined by measurable energy barriers. Increasing guidewire stiffness or decreasing catheter stiffness reduced the energy barrier for successful navigation while increasing that for herniation. This framework enables the prediction of endovascular herniation risk and offers unique insight into improved device design and clinical decision-making.

Recurrent artery of Heubner aneurysms in focus: insights into occurrence and current treatment paradigms

INTRODUCTION

The recurrent artery of Heubner (RAH), also known as the medial striate artery, is the most clinically important perforator of the anterior cerebral artery. RAH aneurysm is relatively rare, with 11 cases found in the present literature review, but poses significant clinical challenges due to potential impact on cognitive and motor functions. This systematic review explored available case reports to comprehensively understand clinical presentation, diagnosis, management and outcome in RAH aneurysm.

MATERIALS AND METHODS

Following PRISMA guidelines, this systematic review extensively explored RAH aneurysms, covering demographics, symptoms, diagnosis, treatments and outcomes. Comprehensive searches on PubMed, Scopus, Google Scholar, and Science Direct employed keywords such as "recurrent artery of Heubner aneurysm" and "Heubner's artery."

RESULTS

After extensive screening, 9 qualifying studies were identified, with 11 patients diagnosed with rare RAH aneurysm. Median age was 55 years (standard deviation, 15.3 years), with 54.5% males. 45.5% of patients presented risk factors, including Moyamoya disease in 2 patients. The majority were classified as grade I/II on the Hunt and Hess (H&H) and World Federation of Neurological Societies (WFNS) systems. Aneurysms were predominantly located in the A1 segment, with a mean size of 4.7 mm. Treatments varied, with clipping being the most frequent (63.6%). The mortality rate was 18.2%. Clipping was associated with favorable outcomes but higher rates of infarction.

CONCLUSION

This analysis highlighted the various symptoms, therapy methods and outcomes of RAH aneurysm, with A1 being the predominant origin. Future research should explore potential genetic predisposition factors and novel therapeutic interventions to address gaps in our knowledge.

ReMAR: a preoperative CT angiography guided metal artifact reduction framework designed for follow-up CTA of endovascular coiling

Objective. Follow-up computed tomography angiography (CTA) is necessary for ensuring occlusion effect of endovascular coiling. However, the implanted metal coil will introduce artifacts that have a negative spillover into radiologic assessment.Method. A framework named ReMAR is proposed in this paper for metal artifacts reduction (MARs) from follow-up CTA of patients with coiled aneurysms. It employs preoperative CTA to provide the prior knowledge of the aneurysm and the expected position of the coil as a guidance thus balances the metal artifacts removal performance and clinical feasibility. The ReMAR is composed of three modules: segmentation, registration and MAR module. The segmentation and registration modules obtain the metal coil knowledge via implementing aneurysms delineation on preoperative CTA and alignment of follow-up CTA. The MAR module consisting of hybrid convolutional neural network- and transformer- architectures is utilized to restore sinogram and remove the artifact from reconstructed image. Both image quality and vessel rendering effect after metal artifacts removal are assessed in order to responding clinical concerns.Main results. A total of 137 patients undergone endovascular coiling have been enrolled in the study: 13 of them have complete diagnosis/follow-up records for end-to-end validation, while the rest lacked of follow-up records are used for model training. Quantitative metrics show ReMAR significantly reduced the metal-artifact burden in follow-up CTA. Qualitative ranks show ReMAR could preserve the morphology of blood vessels during artifact removal as desired by doctors.Significance. The ReMAR could significantly remove the artifacts caused by implanted metal coil in the follow-up CTA. It can be used to enhance the overall image quality and convince CTA an alternative to invasive follow-up in treated intracranial aneurysm.

Treatment trends and clinical outcomes of endovascular embolization for unruptured intracranial aneurysms in the pediatric population

BACKGROUND

Owing to the relative rarity of unruptured intracranial aneurysms (UIAs) in the pediatric population, evidence regarding treatment modalities and clinical outcomes remains limited.

OBJECTIVE

To characterize the use and clinical outcomes of endovascular therapy (EVT) and microsurgical clipping (MSC) for pediatric UIAs over a two-decade interval using a large national registry.

METHODS

Pediatric (<18 years of age) UIA hospitalizations were identified in the National Inpatient Sample from 2002 to 2019. Temporal use and clinical outcomes were compared for treatment with EVT and MSC.

RESULTS

Among 734 UIAs identified, 64.9% (n=476) were treated with EVT. Use of EVT significantly increased during the study period from 54.3% (2002-2004) to 78.6% (2017-2019) (P=0.002 by Cochrane-Armitage test). In comparison with those treated with MSC, pediatric patients treated with EVT demonstrated higher rates of favorable outcomes (discharge to home without services) (96.0% vs 91.1%, P=0.006), shorter durations of hospital stay (4.6 vs 10.0 days, P<0.001), and lower rates of ischemic or hemorrhagic procedural-related complications (1% vs 4%, P=0.010). Conservative management also increased significantly over the study period (P<0.001 by Cochrane-Armitage test).

CONCLUSION

A retrospective evaluation of nearly 20 years of population-level data from the United States demonstrates increasing use of EVT for the treatment of pediatric UIAs, with high rates of favorable outcomes and shorter hospital stays in comparison with those treated with microsurgery.

Endoluminal flow diversion as a primary treatment strategy for pediatric traumatic intracranial aneurysms: a case-based review of literature

BACKGROUND

Traumatic intracranial aneurysms (TICAs) constitute a notable portion of pediatric intracranial aneurysms. Their unstable structure dictates a high incidence of rupture or mass effect from enlarging unruptured aneurysms, necessitating prompt diagnosis and treatment. TICAs often lack a true neck or are wide-necked, making them unsuitable for coil embolization and surgical clipping, and their fragile nature poses a risk of rupture during surgical and intrasaccular interventions. Endoluminal flow diverters (FD), deployed without requiring direct access to the aneurysmal sac, have emerged as an appealing sole treatment modality for TICAs. However, the clinical experience with this technique remains limited in the pediatric population.

METHOD

We describe the successful treatment of a paraclinoid TICA in a 4-year-old female using an endoluminal FD alone. Additionally, we conducted a literature review to assess the safety and effectiveness of this treatment modality in pediatric TICAs.

RESULTS

Endoluminal flow diversion led to complete aneurysm obliteration in our case, with no observed complication, at the 9-month follow-up. Our review of the previously reported pediatric TICAs managed by standalone flow diversion highlights this technique as safe, efficient, and promising as a sole treatment modality, particularly in the anterior circulation, with a high rate of persistent total obliteration and a low rate of complications. However, the requirement for long-term antiplatelet therapy with the possibility of frequent dose monitoring and adjustments warrants special attention when using endoluminal FDs. Until guidelines specifically addressing optimal antiplatelet therapy in children with intracranial FDs are formulated, adherence to existing protocols is imperative to avoid in-stent thrombosis.

CONCLUSION

Our literature review and personal experience indicate that endoluminal flow diversion can be a viable treatment approach for pediatric TICAs. However, prospective studies with extensive follow-ups are required to assess the durability of endoluminal FDs in treating pediatric TICAs, considering the long life expectancy of this demographic.

Ruptured Intracranial Aneurysm in a 60-Day-Old Infant: An Extreme Case

The prevalence of aneurysms in children is low when compared to adults, being even rarer in the first year of life. They can be secondary to infections, traumatic brain injury, autoimmune diseases, or connective tissue diseases. Dissecting etiology is rare. A 60-day-old female infant, previously healthy, presented to the emergency department (ED) with irritability and loss of appetite since the preceding day, a fever of one-hour duration, and vomiting. Laboratory analysis revealed a hemoglobin level of 6.5 g/dL, without elevation of inflammatory markers. In the ED, she experienced two episodes, with a one-hour interval, of clonic movements of the upper eyelid and right upper limb, along with conjugate gaze deviation to the same side, which resolved after intravenous diazepam. Levetiracetam was initiated after the second episode. The anterior fontanelle became progressively tense. Brain computed tomography (CT) showed a voluminous intraparenchymal and subarachnoid hemorrhage with an aneurysm at the bifurcation of the left middle cerebral artery (MCA). Initially, an endovascular approach was tried but was not successful due to technical problems. Consequently, a Vaso-CT scan was performed that confirmed a dissecting aneurysm/pseudoaneurysm (8 mm × 10 mm × 10 mm) of the left MCA, originating from the upper wall of the M1 segment. Next, she underwent microsurgical exclusion of the aneurysm using microclips. Post-surgery brain CT showed acute ischemia in the entire MCA region. Follow-up angiography showed complete exclusion of the aneurysm. She evolved to grade 3 monoparesis of the upper limb at the six-month interval follow-up, which has been gradually improving with physical rehabilitation. The next-generation sequencing (NGS) panel for aneurysms and arterial dissections did not detect any pathogenic variants. Clinical presentation of cerebral aneurysms in infants can be subtle, and a high index of suspicion is required in cases of irritability, altered consciousness, seizures, bulging fontanelle, and motor deficits. Early detection is of utmost importance as it is associated with moderate mortality. Surgical treatment with the use of clips proved to be effective in this case.

Periprocedural management of patients presenting for neurointerventional procedures using flow diverters for complex intracranial aneurysms: An anesthetist's perspective - A narrative review

Complex intracranial aneurysms pose significant challenges in the realm of neurointervention, necessitating meticulous planning and execution. This article highlights the crucial roles played by anesthetists in these procedures, including patient assessment, anesthesia planning, and continuous monitoring and maintaining hemodynamic stability, which are pivotal in optimizing patient safety. Understanding these complex procedures and their complications will aid the anesthetist in delivering optimal care and in foreseeing and managing the potential associated complications. The anesthetist's responsibility extends beyond the procedure itself to postprocedure care, ensuring a smooth transition to the recovery phase. Successful periprocedural anesthetic management in flow diverter interventions for complex intracranial aneurysms hinges on carefully orchestrating these elements. Moreover, effective communication and collaboration with the interventional neuroradiologist and the procedural team are emphasized, as they contribute significantly to procedural success. This article underscores the essential requirement for a multidisciplinary team approach when managing patients undergoing neurointerventions. In this collaborative framework, the expertise of the anesthetist harmoniously complements the skills and knowledge of other team members, contributing to the overall success and safety of these procedures. By providing a high level of care throughout the periprocedural period, anesthetists play a pivotal role in enhancing patient outcomes and minimizing the risks associated with these intricate procedures. In conclusion, the periprocedural anesthetic management of neurointervention using flow diverters for complex intracranial aneurysms is a multifaceted process that requires expertise, communication, and collaboration.

Quantification of the flexural rigidity of endovascular surgical devices using three-point bending tests

Endovascular surgical procedures require the navigation of catheters and wires through the vasculature to reach distal target sites. Quantitative frameworks for device selection hold the potential to improve the tracking of endovascular devices through vascular anatomy by personalizing the device flexural rigidity to an individual's anatomy. However, data are lacking to facilitate this technology, in part because typical endovascular devices have intricate spatial variations in mechanical properties that are challenging and tedious to quantify repeatably. We therefore developed a three-point bend test methodology using a custom rig and applied it to measure lengthwise flexural rigidity profiles of endovascular devices that are used to target the cerebral vasculature. The methodology demonstrated high repeatability and was able to characterize transition zones. We applied the methodology to generate the first comprehensive, quantitative library of device flexural rigidities, spanning guidewires, intermediate guides, and long sheaths. We observed that these three classes of device have properties that fall into distinct ranges. Additional plots examining relationships between flexural rigidity, device diameter, and length revealed application-specific trends in flexural properties. This methodology and the data allow for standardized characterization and comparisons to aid device selection, and have the potential to both enhance surgical planning and inform future innovation.

The Safety and Efficacy of eCLIPs for Treatment of Wide-Necked Bifurcation Aneurysms: A Systematic Review and Meta-Analysis

BACKGROUND

Wide-necked bifurcation aneurysms (WNBAs) are challenging intracranial aneurysms. Several device and treatment approaches have been proposed for the treatment of WNBAs. The endovascular clip system (eCLIPs) is a newly developed endovascular device with flow diverter and flow disruptor features. This study aims to investigate the safety and efficacy of the eCLIPs for treatment of patients with WNBAs.

METHODS

This is a systematic review and meta-analysis study conducted in accordance with the PRISMA (preferred reporting items for systematic reviews and meta-analyses) guidelines. The electronic databases of PubMed, Embase, Scopus, and Web of Science were systematically reviewed from inception to June 19, 2023. The rate of complete and near-complete occlusion, successful device implantation, and serious adverse events were pooled using STATA, version 17.

RESULTS

A total of 5 studies with 110 patients with WNBAs were systematically investigated. Our findings show that the immediate successful implantation rate of eCLIPs was 0.93 (95% confidence interval [CI], 0.88-0.97). Moreover, the immediate postoperative complete occlusion rate was 0.34 (95% CI, 0.10-0.58), and the immediate postoperative near-complete occlusion rate was 0.35 (95% CI, 0.24-0.45). Also, the near-complete occlusion rate at the latest follow-up was 0.3 (95% CI, 0.16-0.44). The serious adverse event rate was 0.14 (95% CI, 0.05-0.22). Stroke was also reported in 2 studies, with 1 study reporting 1 patient who experienced stroke within the first 24 hours and 1 study reporting no patients with stroke.

CONCLUSIONS

Our findings document that the eCLIPs is a safe and effective device for treating patients with WNBAs and associated with favorable outcomes.