Intra-aneurysmal thrombosis as a possible cause of delayed aneurysm rupture after flow-diversion treatment

Understanding heterogeneity of pragmatic trial results and subgroup analyses: The FIAT example

BACKGROUND AND PURPOSE

Pragmatic trial results are intrinsically heterogeneous and the 'average treatment effect', on which the paradigmatic verdict of explanatory trials is based may not suffice to translate trial results into clinically meaningful conclusions applicable in practice. Examining various subgroups is problematic because they are at risk of both false negative and false positive results.

METHODS

We summarize FIAT, a pragmatic care trial on flow diversion where multiple subgroups were examined. The notions of average treatment effect and interaction tests are reviewed to better understand their application in pragmatic trials.

RESULTS

The trial showed flow diversion to be superior to standard treatments, but the results do not apply to all intracranial aneurysms. The notion of a 'true average treatment effect' can hardly apply when there are multiple comparator interventions and clinical heterogeneity. Various subgroups were examined in spite of negative interaction tests, to help interpret the trial results. Subgroup findings can be credible so long as they are not data-dependent 'fishing expeditions'. Meaningful clinical subgroups that have been pre-specified and integrated into the randomization scheme and power calculation provide the most credible conclusions.

CONCLUSION

Non-prespecified data-dependent subgroup analyses are at high risk of being incorrect and should not be used to make clinical decisions in practice. A critical assessment of pre-specified subgroup analyses can nonetheless help interpret heterogeneous pragmatic trial results.

Investigating Delayed Rupture of Flow Diverter-Treated Giant Aneurysm Using Simulated Fluid-Structure Interactions

Giant intracranial aneurysms are frequently treated shortly after discovery due to their increased risk of rupture and commonly symptomatic nature. Among available treatments, flow diverters are often the sole viable option, though they carry a rare but serious risk of delayed post-operative rupture. The underlying mechanisms of these ruptures remain unknown, due to the biomechanical complexity of giant aneurysms and challenges in replicating in vivo hemodynamic conditions within numerical simulation frameworks. This study presents a novel fluid-structure interaction simulation of a giant intracranial aneurysm treated with a flow diverter, based on high-resolution rotational angiography imaging. The resulting hemodynamics are compared to three established delayed-rupture hypotheses involving pressure rises, chaotic flow and autolysis. When considering wall compliance, the analysis reveals a consistent phase shift, dampening in pressure cycles, and an increased aneurysmal flow. These findings highlight the need for revisiting existing hypotheses and provide a foundation for advancing both computational modelling and clinical management strategies for giant intracranial aneurysms.

Flow Diversion for the Treatment of Middle Cerebral Artery Aneurysms

The invention of flow diverting stents (FDS) is a novel milestone in the field of endovascular aneurysm therapy, promoting physiological healing of the vessel segment contrary to prior deconstructive treatment strategies, such as coiling. The effects of FDS are based on changes in flow patterns, segmental wall stabilization, and the growth of a neointima. Although flow diversion is already well established for cerebral aneurysms in proximal segments, peripheral locations remain challenging. Especially the middle cerebral artery (MCA) with its predominance of non-collateralized perforators and functional end arteries that supply the eloquent areas of the brain is of major concern.The literature was reviewed for flow diversion of the MCA and antiplatelet therapy.Resulting from the special anatomical characteristics of the MCA, FDS implantation in this territory is completely different from the proximal vessel segments. Still, flow diversion represents an effective endovascular strategy, especially in otherwise non-accessible or sufficiently treatable lesions. However, the risk of ischemic adverse events might be increased. Special attention to the individual decision regarding device selection, antiplatelet regimen, and exact definition of the proximal and distal landing zone considering the jailed side branches is essential for a good angiographic and clinical outcome. · MCA aneurysms can be sufficiently treated by FDS.. · The anatomic and hemodynamic characteristics of the MCA result in an increased risk of thromboembolism.. · Individual device selection and antiplatelet regimen are essential for treatment success.. · Schüngel M, Wohlgemuth WA, Elolf E et al. Review: Flow Diversion for the Treatment of Middle Cerebral Artery Aneurysms. Rofo 2025; DOI 10.1055/a-2343-0046.

Intraoperative electrophysiological balloon test occlusion (BTO): A novel Solution to an inconclusive conventional BTO

Parent Artery Occlusion (PAO) is a valid treatment choice in giant internal carotid artery (ICA) aneurysms of the cavernous segment when the preoperative balloon test occlusion (BTO) demonstrates an adequate cross circulation from the contralateral side. A high flow arterial bypass is, however, mandatory if the result suggests otherwise or is indeterminate. We present here a case of a 72-year lady where the BTO results were inconclusive. Rather than proceeding for the ICA ligation and a high flow bypass straight away, we replicated the BTO in the operation theatre, using intraoperative electrophysiologic neuromonitoring under the general anaesthesia. A temporary clip was applied on the ICA followed by gradual reduction of the blood pressure up to 30% from the baseline and sustained for 30 min. The motor evoked potential (MEP) and somatosensory evoked potential (SSEP) monitoring did not show ipsilateral hemispheric ischemia. Assured by this electrophysiologic evidence, we proceeded with ligation of the cervical ICA. The patient recovered from surgery without any neurological deficits and remains functionally intact at 4-years follow-up. Based on this case, this novel method can be considered a further refinement of the conventional BTO, allowing clarification of the inconclusive results that may sometimes be encountered.

Clinical Outcome of Pipeline Embolization Device with and without Coils to Treat Intracranial Aneurysm: A Systematic Review and Meta-Analysis

BACKGROUND

The use of a Pipeline Embolization Device (PED) in combination with coils (PEDC) to treat intracranial aneurysms remains unclear as to whether it offers significant benefits for the patients because the results have varied.

PURPOSE

This study aimed to investigate the clinical outcome of the PEDC compared with the PED in treating intracranial aneurysms.

DATA SOURCES

We systematically searched the articles from PubMed, Web of Science, and the Cochrane Library databases published before January 25, 2024.

STUDY SELECTION

We selected studies comparing the PEDC versus the PED to treat intracranial aneurysms. Patients treated with the PEDC but using dense coiling were excluded from the study.

DATA ANALYSIS

The clinical outcomes observed in this meta-analysis were intraprocedural complications, postoperative complications (stenosis, stroke, hemorrhage, mortality), favorable outcome (mRS ≤2), complete occlusion rate, and retreatment rate. A forest plot was used to analyze pooled OR of clinical outcomes.

DATA SYNTHESIS

A total of 3001 subjects from 9 observational studies were included. The PEDC was mainly used to treat larger aneurysms. The PEDC has a significantly higher complete occlusion rate at 6 months (OR = 2.66; 95% CI, 1.26-115.59; P = .01), a lower retreatment rate (OR = 0.18; 95% CI, 0.05-0.07; P = .010), higher stroke-related complications (OR= 1.66, 95% CI, 1.16-2.37; P = .005), and higher hemorrhage-related complications (OR = 1.98; 95% CI, 1.22-13.21; P = .005). There was no significant difference in intraprocedural complications, stenosis-related complications, mortality, favorable outcomes, and complete occlusion at the end of the study.

LIMITATIONS

No randomized controlled trials have been performed comparing the PEDC and PED. Considering that all the included studies were observational, the patients' baseline characteristics were not completely balanced.

CONCLUSIONS

This meta-analysis study showed that the PEDC in large intracranial aneurysms induces a faster complete occlusion rate at 6 months and a lower retreatment rate. However, it increases the risk of stroke-related postoperative complications, and the faster complete aneurysm occlusion rate found in this study did not correlate with a reduction in long-term aneurysm or distal artery ruptures. Thus, this study suggests the need to find a better strategy to improve long-term hemorrhage-related complications in large intracranial aneurysms.

Off-label in-silico flow diverter performance assessment in posterior communicating artery aneurysms

BACKGROUND

The posterior communicating artery (PComA) is among the most common intracranial aneurysm locations, but flow diverter (FD) treatment with the widely used pipeline embolization device (PED) remains an off-label treatment that is not well understood. PComA aneurysm flow diversion is complicated by the presence of fetal posterior circulation (FPC), which has an estimated prevalence of 4-29% and is more common in people of black (11.5%) than white (4.9%) race. We present the FD-PComA in-silico trial (IST) into FD treatment performance in PComA aneurysms. ISTs use computational modeling and simulation in cohorts of virtual patients to evaluate medical device performance.

METHODS

We modeled FD treatment in 118 virtual patients with 59 distinct PComA aneurysm anatomies, using computational fluid dynamics to assess post-treatment outcome. Boundary conditions were prescribed to model the effects of non-fetal and FPC, allowing for comparison between these subgroups.

RESULTS

FD-PComA predicted reduced treatment success in FPC patients, with an average aneurysm space and time-averaged velocity reduction of 67.8% for non-fetal patients and 46.5% for fetal patients (P<0.001). Space and time-averaged wall shear stress on the device surface was 29.2 Pa averaged across fetal patients and 23.5 Pa across non-fetal (P<0.05) patients, suggesting FD endothelialization may be hindered in FPC patients. Morphological variables, such as the size and shape of the aneurysm and PComA size, did not affect the treatment outcome.

CONCLUSIONS

FD-PComA had significantly lower treatment success rates in PComA aneurysm patients with FPC. We suggest that FPC patients should be treated with an alternative to single PED flow diversion.

Aneurysm dome and vessel pressure measurements with coiling, stent assisted coiling and flow diversion

BACKGROUND

Variability in long-term endovascular treatment outcomes for intracranial aneurysms has prompted questions regarding the effects of these treatments on aneurysm hemodynamics. Endovascular techniques disrupt aneurysmal blood flow and shear, but their influence on intra-aneurysmal pressure remains unclear. A better understanding of aneurysm pressure effects may aid in predicting outcomes and guiding treatment decisions.

METHODS

Medium and large aneurysm models with intramural pressure taps on the dome and parent artery were designed and 3D-printed with vessel-like physical properties from UV-cured materials. The models were connected to a comprehensive flow system consisting of a pulsatile pump and a viscosity-matched blood analog. The system provided physiological pressure and flow control. Real-time pressures were recorded in the aneurysm dome and parent artery during initial placement of coils, stents, flow diverters, and temporary balloons under simulated surgical conditions. Coiling, stent-assisted coiling, and flow diverter placement were performed in both aneurysm sizes. Temporary balloon placement was performed in a large aneurysm model.

RESULTS

Coiling resulted in 24-30% packing density and diminished intra-aneurysmal flow. Flow diverter placement reduced intra-aneurysmal flow with near complete flow interruption after placement of three consecutive devices across the aneurysm neck. Compared to untreated controls, real-time pressure measurements during coiling and flow diversion showed minimal changes (< 5%) in intra-aneurysmal pressures. Temporary balloon occlusion blocked the parent artery, increasing the pressure proximal to the site of occlusion (by 9%), and reducing the pressure distally (by 14%). This maneuver also dampened intra-aneurysmal pressure to the average distal vessel pressure measurement. Positive control aneurysm models were 3D-printed with a sealed, "healed" neck. These controls verified a sealed neck eliminates intra-aneurysmal pressure.

CONCLUSION

Findings quantified minimal changes in intra-aneurysmal pressure during and immediately post-coiling and flow diversion. Intra-aneurysmal flow disruption alone has negligible impact on intra-aneurysmal pressures.

Delayed destabilization and rupture of a giant anterior circulation aneurysm following flow-diverter placement: A case report

Flow-diverting stents have been increasingly utilized for the treatment of intracranial aneurysms, especially when there are factors that go against coil embolization, such as wide neck and large aneurysm size. However, its use does not guarantee success, especially in giant lesions, and failure to obtain aneurysmal obliteration can result in long-term instability of the aneurysmal wall, leading to aneurysmal growth and late rupture. We present the case of a 65-year-old woman who suffered from a late aneurysmal dilation and rupture, 2 years and 4 months after flow-diverting treatment of a giant ophthalmic segment aneurysm. Although not fully understood, the pathophysiology of this phenomenon has one necessary factor: incomplete aneurysmal obliteration. When this scenario is present, two main factors take place: the augmentation of intrasaccular blood flow after stent delivery and the local inflammation caused by partial thrombus formation and the presence of the stent itself. To prevent this complication, complete aneurysmal obliteration must be assured, and the use of combined techniques is encouraged.

Aneurysm healing following treatment with biodegradable embolization materials: assessment in a rat sidewall aneurysm model

BACKGROUND

Biodegradable materials that dissolve after aneurysm healing are promising techniques in the field of neurointerventional surgery. We investigated the effects of various bioabsorable materials in combination with degradable magnesium alloy stents and evaluated aneurysm healing in a rat aneurysm model.

METHODS

Saccular aneurysms were created by end-to-side anastomosis in the abdominal aorta of Wistar rats. Untreated arterial grafts were immediately transplanted (vital aneurysms) whereas aneurysms with loss of mural cells were chemically decellularized before implantation. All aneurysms were treated with biodegradable magnesium stents. The animals were assigned to vital aneurysms treated with stent alone or decellularized aneurysms treated with stent alone, detachable coil, or long-term or short-term biodegradable thread. Aneurysm healing, rated microscopically and macroscopically at follow-up days 7 and 21, was defined by both neointima formation and absence of aneurysm volume increase over time.

RESULTS

Of 56 animals included, significant increases in aneurysm volume 7 days after surgery were observed in aneurysms with vital and decellularized walls treated with a stent only (P=0.043 each group). Twenty-one days after surgery an increase in aneurysm volume was observed in decellularized aneurysms treated with long- and short-term biodegradable threads (P=0.027 and P=0.028, respectively). Histological changes associated with an increase in aneurysm volume were seen for aneurysm wall inflammation, periadventitial fibrosis, and luminal thrombus.

CONCLUSIONS

An increase in aneurysm volume was associated with an absence of intrasaccular embolization material (early phase) and the breakdown of intrasaccular biodegradable material over time (late phase). Thrombus remnant and aneurysm wall inflammation promote aneurysm volume increase.

Late complications of visual impairment and hydrocephalus after flow diverter-assisted coil embolisation for intracranial large aneurysm: a case report and literature review

Large or giant paraclinoid aneurysms typically have good indication for flow diverter (FD) treatment. Here, we report a very rare case of a patient with an unruptured supraclinoid large aneurysm who underwent FD deployment with coil embolisation that resulted in delayed visual field defect (VFD) and hydrocephalus. A 75-year-old woman with a large right supraclinoid aneurysm presented with severe hemianopia in the right eye. She underwent FD deployment with coil embolisation of the aneurysm. However, permanent left visual field loss occurred four months after surgery. Magnetic resonance imaging (MRI) showed severe oedema surrounding the aneurysm along the optic tract. Inflammation led to postoperative hydrocephalus, requiring ventriculoperitoneal shunt placement. To the best of our knowledge, this is the first report of both a delayed VFD and hydrocephalus following FD treatment. In cases of FD treatment with coil embolisation for large paraclinoid aneurysms, clinicians should keep in mind that postoperative visual impairment or/and hydrocephalus may occur.

Circulating miRNA profiles as predictive biomarkers for aneurysm healing following endovascular treatment: a prospective study

BACKGROUND

Aneurysm treatments are crucial to minimize the rupture risk. The underlying molecular processes mediating cellular remodeling, endothelialization, and aneurysm healing following endovascular treatment are poorly understood. The current study aims to explore circulating miRNA as a treatment and outcome-associated biomarkers in patients undergoing endovascular treatment.

METHODS

Patients undergoing endovascular interventions for unruptured intracranial aneurysms, using either flow diverter placement or coil embolization, were enrolled. Blood samples were collected before the intervention and during a follow-up period between 6 and 18 months. Total mRNA/miRNA was isolated from plasma, followed by RNA-seq analysis. Gene Ontology analysis was used to identify pathways linked to altered miRNA expression.

RESULTS

Twenty-three patients participated, with 13 (56.5%) undergoing flow diversion and 10 (43.5%) coil embolization. The median follow-up sample collection time was 10.70 months (SEM ± 1.32). No significant differences in angiographic occlusion were noted between intervention groups. Differentially expressed miRNAs were not identified between groups at baseline. However, at follow-up, 39 miRNAs were upregulated and 41 were downregulated, independent of intervention. Notably, three miRNAs (miR-4746-5p, miR-4685-3p, and miR-490-3p) were downregulated in the flow diversion group compared to the coil embolization group. Bioinformatics analysis revealed associations with upregulated fluid shear stress, p53, adherens junction pathways, along with downregulated apoptosis pathways.

CONCLUSIONS

This study suggests that fluid shear stress and apoptosis may influence aneurysm healing or thromboembolic events in flow diverter-treated patients. Further research is warranted to elucidate the functional significance of these findings in treatment outcomes, providing valuable insights for improved patient care in intracranial aneurysm management.

Advancements in Brain Aneurysm Management: Integrating Neuroanatomy, Physiopathology, and Neurosurgical Techniques

Brain aneurysms, characterized by abnormal bulging in blood vessels, pose significant risks if ruptured, necessitating precise neuroanatomical knowledge and advanced neurosurgical techniques for effective management. This article delves into the intricate neuroanatomy relevant to brain aneurysms, including the vascular structures and critical regions involved. It provides a comprehensive overview of the pathophysiology of aneurysm formation and progression. The discussion extends to modern neurosurgical approaches for treating brain aneurysms, such as microsurgical clipping, endovascular coiling, and flow diversion techniques. Emphasis is placed on preoperative planning, intraoperative navigation, and postoperative care, highlighting the importance of a multidisciplinary approach. By integrating neuroanatomical insights with cutting-edge surgical practices, this article aims to enhance the understanding and treatment outcomes of brain aneurysms.

Effectiveness of Flow Diverter Stents in the Treatment of Intracranial Aneurysms: Single-Center 10-Year Results

Purpose This study's objective was to show how effectively flow-diverting stents work when treating cerebral aneurysms. The assessment aimed to determine efficaciousness related to aneurysm type, size, and location as well as early- and late-term results. Material and method The study included 153 aneurysms from 122 patients treated in interventional radiology unit with flow diverter stents between July 2010 and June 2020. Apart from demographic data, size, type, and location of aneurysms; technical success, peri, post-procedural, and late complications; aneurysm occlusion rates, morbidity and mortality rates were extracted from patient records. Results This study enrolled 90 (73.8%) females and 32 (26.2%) males; average age of the patients was 52.8±12.9. The average follow-up period was 33.4±9.9 months. The most common type of aneurysm was saccular (133; 86.9%), and the most common location was the supraclinoid segment with 67 (43.8%). Complete occlusion was observed in 115 of 140 aneurysms from 110 patients during follow-up. No statistically significant difference was detected between the sizes and types of aneurysms and complete occlusion rates (p=0.096, p=0.583). The total occlusion rate was found to be significantly higher in internal carotid artery (ICA) supraclinoid segment aneurysms compared to other locations (p = 0.006). During the follow-up period, flow diverter stent-related permanent morbidity was observed in four (3.6%) patients and mortality was observed in five (4.5%) patients. Conclusion Flow diverter stents can be successfully applied to many aneurysm types, from small aneurysms to large and giant aneurysms, and have high aneurysm occlusion rates with low morbidity and mortality. By the aspects of the current study the total occlusion rate was found to be significantly higher in ICA supraclinoid segment aneurysms compared to other localizations.

Pipeline Embolization device for the treatment of unruptured intracranial saccular aneurysms: a systematic review and meta-analysis of long-term outcomes

INTRODUCTION

The pipeline embolization device (PED) is commonly used for intracranial aneurysm treatment. While its effectiveness for certain types of aneurysms is well-established, its efficacy for saccular aneurysms remains controversial. We aimed to assess the long-term outcomes of PED treatment for unruptured intracranial saccular aneurysms.

METHODS

Systematic review and meta-analysis were conducted following PRISMA guidelines. Studies with at least one year of follow-up after PED treatment for saccular aneurysms were included. The primary endpoint was angiographic aneurysm occlusion at long-term follow-up (≥ 12 months), and the secondary outcome was long-term complications. We conducted a meta-regression analysis to explore potential sources of heterogeneity across studies.

RESULTS

Eleven studies of 797 patients with 963 aneurysms were included. Long-term angiographic occlusion rate was 85% (95% CI, 77-91%; p < 0.01), symptomatic ischemic stroke rate was 1% (95% CI, 0-3%; p < 0.01), rupture rate was 1% (95% CI, 0-2%; p = 0.02), and intracranial hemorrhage (ICH) rate was 0.2% (95% CI, 0-1%; p = 0.11). Meta-regression analysis revealed a non-significant decreasing trend per year for aneurysmal occlusion, ischemic stroke rate, delayed aneurysmal rupture, and ICH.

CONCLUSION

PED demonstrates high long-term occlusion and low complication rates, suggesting it is a safe and effective treatment option for saccular aneurysms. Additionally, newer devices exhibit reduced thrombogenic profiles and safety with decreasing trends in ICH, ischemic stroke, and delayed aneurysmal rupture.

How Flow Diverter Selection Can Affect the Flow Changes within a Jailed Ophthalmic Artery: A Computational Fluid Dynamics Study

Introduction  Flow diverter (FD) stents are widely used to treat giant aneurysms by reducing blood flow into the aneurysm sac. However, choosing the optimal FD for a patient can be challenging when a nearby artery, such as the ophthalmic artery (OA), is jailed by the FD placement. This study compares the impact of two FD stents with different effective metal surface area (EMSA) values on OA occlusion. Materials and Methods  A numerical model of a 59-year-old female patient with a giant aneurysm in the left internal carotid artery and a jailed OA was created based on clinical data. Two FD stents, FRED4017 and FRED4518, with different EMSA values at the aneurysm neck and OA inlet, were virtually deployed in the model. Blood flow and occlusion amount in the OA were simulated and compared between the two FD stents. Results  FRED4017 had higher EMSA values than FRED4518 at the aneurysm neck (35% vs. 24.6%) and lower EMSA values at the OA inlet (15% vs. 21.2%). FRED4017 caused more occlusion in the OA than FRED4518 (40% vs. 28%), indicating a higher risk of ocular ischemic syndrome. Conclusion  The EMSA value of FD stents affects the blood flow and occlusion amount in the jailed OA. Therefore, selecting an FD stent with a low EMSA value at the OA inlet may be beneficial for patients with a nearby jailed artery at the aneurysm neck.

Application of 3D printing to create an in vitro aneurysm rupture model

Currently available benchtop (in vitro) aneurysm models are inadequate for testing the efficacy of endovascular device treatments. Specifically, current models do not represent the mechanical instability of giant aneurysms (defined as aneurysms with 25 mm in height or width) and do not predictably rupture under simulated physiological conditions. Hence, in vitro aneurysm models with biomechanically relevant material properties and a predictable rupture timeframe are needed to accurately assess the efficacy of new medical device treatment options. Understanding the material properties of an aneurysm (e.g., shear and compression modulus) as it approaches rupture is a crucial step toward creating a pathologically relevant and sophisticated in vitro aneurysm rupture model. We investigated the change in material properties of a blood vessel, via enzymatic treatment, to simulate the degradation of an aneurysm wall and used this information to create a sophisticated aneurysm rupture model using the latest in additive manufacturing technologies (3D printing) with tissue-like materials. Mechanical properties (shear and compression modulus) of swine carotid vessels were evaluated before and after incubation with collagenase D enzyme (30 min at 37°C) to simulate the effect of biochemical activity on aneurysm wall approaching rupture compared to control vessels (untreated). Mechanical strength of a soft and flexible 3D-printed material (VCA-A30: 30 shore A hardness) was tested for comparison to these arterial vessels. This material was then used to create spherical shaped, giant-sized (25-mm diameter) aneurysm phantoms and were run under neurovascular pressures (120/80 ± 5 mmHg), beats per minute (BPM = 70) and flows representing the middle cerebral artery [MCA: 142.67 (±20.13) mL/min] using a blood analog [3.6 (±0.4) cP viscosity] with non-Newtonian shear-thinning properties. The shear modulus of swine carotid vessel before treatment was 12.2 (±2.7) KPa and compression modulus was 663.5 (±111.6) KPa. After enzymatic treatment by collagenase D, shear modulus of animal tissues reduced by 33% (p-value = .039) while compression modulus remained statistically unchanged (p-value = .615). Control group (untreated vessels) showed minimal reduction (13%, p-value = .226) in shear modulus and 78% increase (p-value = .034) in compression modulus. The shear modulus of the 3D-printed material was 228.59 (±24.82) KPa while its compression modulus was 668.90 (±13.16) KPa. This material was used to prototype a sophisticated in vitro giant aneurysm rupture model. When subjected to physiological pressures and flow rates, the untreated models consistently ruptured at ~12 min. These results indicate that aneurysm rupture can be recreated consistently in a benchtop in vitro model, utilizing the latest 3D-printed materials, connected to a physiologically relevant programmable pump. Further studies will investigate the optimization of various aneurysm dome thickness regions within the aneurysm, with tunable rupture times for comparison of aneurysm device deployment and benchtop controls based on the measurable effects of pressure and flow changes within the aneurysm models. These optimized in vitro rupture models could ultimately be used to test the efficacy of device treatment options and rupture risk by quantifying specific device rupture times and aneurysm rupture position.

Preoperative middle meningeal artery embolization in the treatment of organized chronic subdural hematoma

Organized chronic subdural hematoma is a rare form of chronic subdural hematoma. The optimal treatment method is still controversial. Preoperative middle meningeal artery embolization and craniotomy are effective methods for chronic subdural hematoma. However, there are not many reports investigating the effectiveness of these methods in treating organized chronic subdural hematoma. We report the case of a 61-year-old male patient who had a twist-drill craniostomy to treat a left hemisphere subdural hematoma. After surgery, there was a recurrence on the same side in the form of an organized subdural hematoma. The patient received preoperative left middle meningeal artery embolization. After 3 months of follow-up, a small portion of the hematoma remained, causing pressure and slightly shifting the midline to the right by 6.5 mm, and the patient no longer had clinical symptoms.

Neuroform atlas stent treatment for 533 intracranial aneurysms in a large Chinese cohort: complication risk factor analysis

BACKGROUND

The newest generation of Neuroform Atlas stent™ (Stryker, Fremont, California) represents a recent advance of cerebral laser-cut microstents for the treatment of intracranial wide-necked aneurysms, and postoperative complications have been observed among Western patients. We assessed predictors of complications, morbidity, and unfavourable outcomes in a large cohort of patients with aneurysms that were treated with Neuroform Atlas stents in China.

METHODS

This retrospective study included subjects who were treated with Atlas stents in China from November 2020 to January 2022.

RESULTS

A total of 522 consecutive patients (mean age, 58.9 ± 9.9 years; female, 65.3% [341/522]) with 533 aneurysms were included in the study. In the early postoperative period, the neurological morbidity rate was 7.3% (38/522), the ischaemic stroke rate was 5.0% (26/522), the aneurysm rupture subarachnoid haemorrhage rate was 2.3% (12/522), and the mRS score deterioration rate was 5.4% (28/522). The mortality rate was 0.8% (4/522) in the postoperative period. The rate of neurological morbidity during the follow-up period was 1.2% (6/486). In the multifactor prediction analysis, cerebral infarction, Hunt-Hess grade (3-5), procedure duration, stent length and coil protrusion into the parent artery were found to be independent predictors of neurologic morbidity. The procedure duration, stent length and coil protrusion into the parent artery were found to be independent predictors of mRS score deterioration.

CONCLUSIONS

The incidence of SCA (stent-assisted coiling)-related complications with the Atlas stent in this study population was comparable to that in Western populations. We identified the procedure duration and stent length as novel independent predictors of SCA-related ischaemic stroke, neurological morbidity, and mRS score deterioration among the Chinese population.

It Is Necessary to Pay Attention to Where the Pcom Originate from the Aneurysm to Treat with FD

Objective  With the expansion of indications of flow diverter (FD) for cerebral aneurysms, FD placement for posterior communicating artery (Pcom) aneurysms has been approved. However, it is controversial whether Pcom aneurysms should be treated with FD or not. In this study, we report the outcome of FD treatment for Pcom aneurysms in Japan. Materials and Methods  We retrospectively analyzed 36 patients with 38 aneurysms treated with FD placement for Pcom aneurysms between 2015 and 2021 in our hospital. We divided our cases into complete occlusion (CO) and non-CO groups. And we extracted contributing factors to CO using multivariate analysis. We also compared the complications rate among the three types of FDs. Results  CO was obtained in 29 cases (79.3%), and complications were observed in 3 cases (7.9%). Multivariate analysis revealed that the type of Pcom branch from the aneurysmal dome was a significant factor contributing to CO (odds ratio: 0.0052, 95% confidence interval 0.000048-0.584, p  = 0.029). In terms of complications, complication rate was significantly higher in the Flow-Redirection Endoluminal Device (FRED) group ( p  = 0.0491). Conclusion  The outcome for Pcom aneurysms treated by FD was acceptable. When treating, we must pay attention to where Pcom originates. Achieving CO with FD is difficult for aneurysms where the Pcom branches from the dome. Furthermore, when treating Pcom aneurysms with FRED, it is necessary to be careful about thromboembolic complications.

Clinical Outcomes On Tubridge Flow Diverter in Treatmenting Intracranial Aneurysms: a Retrospective Multicenter Registry Study

PURPOSE

In China, the application of nitinol Tubridge flow diverter (TFD) has become popular for treating intracranial aneurysms (IAs). In this study, we investigated the safety outcomes of the application of TFD for treating IAs in real-world scenarios.

METHODS

We retrospectively analyzed aneurysms treated with TFD in 235 centers throughout China between April 2018 and April 2020. The primary endpoint was the event-free survival rate at 12 months, defined as the occurrence of morbidity (spontaneous rupture, intraparenchymal hemorrhage (IPH), ischemic stroke, and permanent cranial neuropathy) or death. Univariate and multivariate analyses were performed to assess the risk factors. A good outcome was defined as a modified Rankin Score (mRS) of 0-2.

RESULTS

We included 1281 unruptured aneurysms treated with TFD. The overall neurological morbidity and death rates after 12 months were 5.4 and 2.8%, respectively. Ischemic strokes were the most common complication (4.2%, P < 0.001). Cranial neuropathy, IPH, and spontaneous rupture occurred in 0.3%, 0.3%, and 0.5% of aneurysms, respectively. Univariate and multivariate analyses indicated that the male gender, older age, larger aneurysm diameter, and aneurysm located on BA were the independent risk factors for neurologic events. Aneurysm located on BA was the independent risk factor for ischemic strokes. Most patients (1222) had access to the mRS, and 93.2% of them achieved good outcomes.

CONCLUSION

Treatment of IAs with TFD was associated with low morbidity and mortality, most of which were ischemic events. Large posterior aneurysms might be associated with a higher complication rate.

TRIAL REGISTRATION

Retrospectively registered.

Evaluation of the Significance of Persistent Remnant Filling and Enlargement After Flow Diversion for Intracranial Aneurysms

BACKGROUND

This study aimed to evaluate the clinical course after flow diversion (FD) treatment with a focus on aneurysms with remnant sac filling, by analyzing angiographic outcomes, aneurysm volume, and clinical events.

METHODS

We retrospectively reviewed the medical records of 61 patients who underwent FD for intracranial aneurysms between July 2014 and June 2021.

RESULTS

The majority of aneurysms (52.5%) were located in the internal carotid artery, with a median diameter of 16.6 mm and neck size of 9.3 mm. Remnant filling was observed in 17 aneurysms (27.9%) more than 18 months after FD, 10 (16.4%) of these aneurysms underwent enlargement, which occurred only in cases with subtotal filling or entry remnant states. Eleven patients experienced major adverse events, and three exhibited unfavorable functional outcomes. The incidence of major adverse events and unfavorable functional outcomes was significantly higher in the aneurysm enlargement group than that in the no-filling or stable remnant filling groups (P < 0.001). Aneurysmal diameter and the presence of incorporated branches were independent predictors of aneurysm enlargement, while the presence of incorporated branches was the only independent predictor of persistent remnant filling.

CONCLUSIONS

Aneurysm enlargement after FD is not uncommon, particularly when the aneurysm is large, has incorporated vessels, or does not undergo occlusion within 12 months, often culminating in major adverse events and unfavorable functional outcomes. In addition to investigating angiographic results, it is necessary to evaluate the changes in aneurysm size and clinical events when assessing the efficacy of FD.

Predicting postinterventional rupture of intracranial aneurysms using arteriography-derived radiomic features after pipeline embolization

BACKGROUND AND PURPOSE

Postinterventional rupture of intracranial aneurysms (IAs) remains a severe complication after flow diverter treatment. However, potential hemodynamic mechanisms underlying independent predictors for postinterventional rupture of IAs remain unclear. In this study, we employed arteriography-derived radiomic features to predict this complication.

METHODS

We included 64 patients who underwent pipeline flow diversion for intracranial aneurysms, distinguishing between 16 patients who experienced postinterventional rupture and 48 who did not. We performed propensity score matching based on clinical and morphological factors to match these patients with 48 patients with postinterventional unruptured IAs at a 1:3 ratio. Postinterventional digital subtraction angiography were used to create five arteriography-derived perfusion parameter maps and then radiomics features were obtained from each map. Informative features were selected through the least absolute shrinkage and selection operator method with five-fold cross-validation. Subsequently, radiomics scores were formulated to predict the occurrence of postinterventional IA ruptures. Prediction performance was evaluated with the training and test datasets using area under the curve (AUC) and confusion matrix-derived metrics.

RESULTS

Overall, 1,459 radiomics features were obtained, and six were selected. The resulting radiomics scores had high efficacy in distinguishing the postinterventional rupture group. The AUC and Youden index were 0.912 (95% confidence interval: 0.767-1.000) and 0.847 for the training dataset, respectively, and 0.938 (95% confidence interval, 0.806-1.000) and 0.800 for the testing dataset, respectively.

CONCLUSION

Radiomics scores generated using arteriography-derived radiomic features effectively predicted postinterventional IA ruptures and may aid in differentiating IAs at high risk of postinterventional rupture.

Ongoing Geometric Remodeling of the Parent Artery After Flow-Diverter Stent Reconstruction in Cerebral Aneurysms: The Device Design Matters

OBJECTIVE

Configuration changes of the parent artery (PA) after flow-diverter (FD) stent reconstruction, caused by the bending force of the device, may have an additional role in aneurysm occlusion as a result of the secondary alteration of intra-aneurysmal hemodynamics related to the geometry alteration of the vessel. To determine the degree of PA deformation and aneurysm occlusion rates after deployment of 2 different types of FD.

METHODS

Patients treated with 2 different designs of cobalt-chromium braid (48 and 64 wire braid) structure FD were subject to analysis. Vascular angle changes at the level of the reconstructed segment immediately after FD deployment and at 1 year follow-up were measured and the potential relationship with aneurysmal occlusion rate was analyzed.

RESULTS

Forty-two patients harboring 48 aneurysms were included in the present study. The aneurysms were divided into side wall (85.4%) and bifurcation types (14.6%). Twenty-six aneurysms were treated using the Pipeline FD (48 wire braid; 54.2%) and 22 using the Evolve FD (64 wire braid; 45.8%). Of the 48 aneurysms, 42 (87.5%) met the primary end point of complete occlusion at 12 months. The median postdeployment angle change was 7.04°± 4.59° for the Pipeline and 5.05°± 2.49° for the Evolve, whereas the median 12 months follow-up angle change was 15.49°± 10.99° and 10.01°± 8.83°, respectively. PA angle changes were significantly higher in the bifurcation group compared with the side wall group both during procedure and at 12 months follow-up. Angle change had a statistically nonsignificant association with complete aneurysm occlusion.

CONCLUSIONS

PA deformation starts immediately after deployment and remodeling continues for 1 year after. Aneurysms located in the vessel bifurcation were more prone to PA straightening after FD deployment than were side wall aneurysms. Furthermore, Pipeline seemed to be more prone to inducing vascular deformation, compared with Evolve.

A Review of Current Flow Diverters

Flow diverter (FD) devices are new-generation stents placed in the parent artery at the aneurysmal neck to obstruct intra-aneurysmal blood flow, thus favoring intra-aneurysmal thrombosis. In Japan, about eight years have passed since health insurance approval was granted for FD devices, and FD placement to treat aneurysms has become widespread. Treatment indications have also been expanded with the introduction of novel devices. At present, three types of FD (Pipeline, FRED, and Surpass Streamline) are available in Japan. This report represents a compilation of available FD technologies and describes the current consensus on this treatment.

Delayed rupture of a large intracranial internal carotid artery aneurysm after flow diverter placement

Background

Delayed rupture after flow diverter (FD) placement is a serious complication, and often it leads to death; however, the exact mechanism leading to the rupture remains unclear. Therefore, in this case, study, we report a case of delayed rupture after FD placement and discuss its causes.

Case Description

This study presents the case of a 69-year-old female with multiple aneurysms who underwent FD placement with coil embolization for a large intracranial internal carotid artery aneurysm. Postoperatively, the patient had no significant symptoms, and angiography and magnetic resonance imaging revealed decreased intra-aneurysmal blood flow. However, on the 3rd postoperative day, she developed a sudden disturbance of consciousness. Computed tomography revealed a massive subarachnoid hemorrhage, diagnosed as a delayed rupture. We decided to withhold therapy due to her serious condition. Previous studies have suggested that hemodynamic mechanisms can cause delayed aneurysm rupture. Based on the computational fluid dynamics (CFD) of the aneurysm, we suggest that an increase in intra-aneurysmal pressure after FD placement may have caused the delayed rupture.

Conclusion

Preoperative CFD analysis may help evaluate the risk of delayed rupture for large aneurysms with a high inflow from the parent vessel.

Predictors of aneurysm shrinkage after flow diversion treatment for internal carotid artery aneurysms: quantitative volume analysis with MRI

Background and purpose

Although aneurysm shrinkage often occurs after flow diversion treatment for intracranial aneurysms, no reports have addressed the factors associated with aneurysm shrinkage.

Materials and methods

This retrospective single-center study was performed to examine patients with unruptured internal carotid artery aneurysms who were treated using flow diversion and followed up by imaging for at least 12 months. The study outcome was aneurysm shrinkage (volume reduction of ≥10%) 12 months after treatment. Aneurysm volume was quantitatively assessed using the MRIcroGL software. Patient and aneurysm characteristics were statistically analyzed.

Results

This study involved 81 patients with 88 aneurysms. At the 6 months, 12 months, and last follow-ups, the proportion of aneurysms that had shrunk was 50, 64, and 65%, respectively. No adjunctive coiling (odds ratio, 56.7; 95% confidence interval, 7.03-457.21; p < 0.001) and aneurysm occlusion (odds ratio, 90.7; 95% confidence interval, 8.32-988.66; p < 0.001) were significantly associated with aneurysm shrinkage. In patients treated by flow diversion with adjunctive coiling, only the volume embolization rate was a factor significantly associated with aneurysm shrinkage (p < 0.001). Its cutoff value was 15.5% according to the receiver operating characteristic curve analysis (area under the curve, 0.87; sensitivity, 0.87; specificity, 0.83).

Conclusion

The rate of aneurysm shrinkage after flow diversion increased during the first 12 months after treatment, but not thereafter. No adjunctive coiling and aneurysm occlusion were predictors of aneurysm shrinkage, respectively. If adjunctive coiling is required, a volume embolization rate of ≤15.5% may be suggested for aneurysm regression.

Multicenter study of the safety and effectiveness of intracranial aneurysm treatment with the p64MW-HPC flow modulation device

BACKGROUND AND PURPOSE

The new p64 flow diverter with hydrophilic polymer coating (HPC) was designed to reduce thrombogenicity. To date, it is unclear how antithrombogenic surface modifications affect neoendothelialization and thrombus formation in patients with unruptured intracranial aneurysms. The purpose of this study was to evaluate the safety and effectiveness of the p64MW-HPC in the treatment of unruptured aneurysms of small to giant size and of both the anterior and posterior circulation.

MATERIALS AND METHODS

Between March 2020 and October 2022 all patients with unruptured intracranial aneurysms treated with the p64MW-HPC were included at five neurovascular centers. Demographic data, aneurysm characteristics, antiplatelet therapy, procedural complications, and clinical and angiographic outcomes were recorded.

RESULTS

A total of 100 patients with 100 unruptured intracranial aneurysms met the inclusion criteria. Eighty-three aneurysms were classified as saccular, 12 aneurysms were fusiform, 4 aneurysms dissecting, and 1 aneurysm was blister-like. Dual antiplatelet therapy with Clopidogrel and Aspirin was given in 68 cases, and with Ticagrelor and Aspirin in 24 cases. Technical issues with deployment were encountered in 14 cases (torsion (n = 3), foreshortening (n = 8), and incomplete opening (n = 3)). Ischemic stroke occurred in a total of seven cases. In one patient a wire perforation and subsequent severe ICH occurred. Complete aneurysm occlusion at angiographic follow-up (mean time = 7 months) was seen in 73% and adequate occlusion in 93%.

CONCLUSION

This study is the largest multicenter study to date documenting the safety and effectiveness of the new antithrombogenic p64MW-HPC in the treatment of unruptured intracranial aneurysms of the anterior and posterior circulation.

Prognostic Factors in Patients with Unruptured Vertebral and Basilar Fusiform Aneurysms Treated with Endovascular Procedures : A Single Center Retrospective Analysis

PURPOSE

Large vertebral and basilar fusiform aneurysms (VFA) are sometimes difficult to cure by endovascular treatment (EVT). We aimed to elucidate indicators of poor outcomes of EVT in patients with VFAs.

METHODS

Clinical data from 48 patients with 48 unruptured VFAs in the Hyogo Medical University were retrospectively analyzed. The primary outcome was defined as satisfactory aneurysm occlusion (SAO) according to Raymond-Roy grading scale. The secondary and safety outcomes were a modified Rankin scale (mRS) score of 0-2 at 90 days, retreatment, major stroke, and aneurysm-related death after EVT.

RESULTS

The EVT included stent-assisted coiling (n = 24; 50%), flow diverter (n = 19; 40%), and parent artery occlusion (n = 5; 10%). The SAO was less frequently observed in large or thrombosed VFAs at 12 months (64%, p = 0.021 and 62%, p = 0.014, respectively), especially when the aneurysms were both large and thrombosed (50%, p = 0.0030). Retreatment was more common in large aneurysms (29%, p = 0.034), thrombosed (32%, p = 0.011), and large thrombosed aneurysms (38%, p = 0.0036). Although the proportion of mRS 0-2 at 90 days and major stroke showed no significant differences, that of post-treatment rupture was significantly larger in large thrombosed VFAs (19%, p = 0.032). Aneurysm-related death occurred by aneurysm rupture and was more frequent in large thrombosed VFA (19%, p = 0.032). Multivariate analysis showed SAO at 12 months was less common (adjusted odds ratio, OR: 0.036, 95% confidence interval, CI 0.00091-0.57; p = 0.018), and retreatment was more common (adjusted OR 43, 95% CI 4.0-1381; p = 0.0012) in large thrombosed VFA.

CONCLUSION

The large thrombosed VFAs were associated with poor outcomes after EVT including flow diverter.

Long-term outcomes and dynamic changes of in-stent stenosis after Pipeline embolization device treatment of intracranial aneurysms

BACKGROUND

Flow diverters have revolutionized the treatment of intracranial aneurysms. However, the delayed complications associated with flow diverter use are unknown.

OBJECTIVE

To evaluate the incidence, severity, clinical outcomes, risk factors, and dynamic changes associated with in-stent stenosis (ISS) after treatment with a Pipeline embolization device (PED).

METHODS

Patients who underwent PED treatment between 2015 and 2020 were enrolled. The angiographic, clinical, and follow-up data of 459 patients were independently reviewed by four neuroradiologists to identify ISS. Binary logistic regression was conducted to determine ISS risk factors, and an ISS-time curve was established to demonstrate dynamic changes in ISS after PED implantation.

RESULTS

Of the 459 treated patients, 69 (15.0%) developed ISS. At follow-up, nine patients (2.0%) with ISS demonstrated reversal, while 18 (3.9%) developed parental artery occlusion. A total of 380 patients (82.8%) achieved complete aneurysm occlusion (O'Kelly-Marotta grade D). Patients with posterior-circulation aneurysm (OR=2.895, 95% CI (1.732 to 4.838; P<0.001) or balloon angioplasty (OR=1.992, 95% CI 1.162 to 3.414; P=0.037) were more likely to develop ISS. Patients aged >54 years (OR=0.464, 95% CI 0.274 to 0.785; P=0.006) or with a body mass index of >28 kg/m2 (OR=0.427, 95% CI 0.184 to 0.991; P=0.026) had a lower ISS risk. Intimal hyperplasia initiated by PED placement peaked within 1 year after the procedure, rarely progressed after 12 months, and tended to reverse within 24 months.

CONCLUSIONS

ISS is a common, benign, and self-limiting complication of PED implantation in the Chinese population.

Trends in Ruptured and Unruptured Aneurysmal Treatment from 2010 to 2020: A Focus on Flow Diversion

OBJECTIVE

Flow diverters are a promising new tool in the neurosurgeon's arsenal for aneurysm management. We sought to quantify the trends of flow diversion in comparison to traditional endovascular coiling and surgical clip ligation techniques in the United States from 2010 to 2020 with an emphasis on aneurysm location and preferences in usage for ruptured versus unruptured aneurysms.

METHODS

In this large cross-sectional study, patients aged 18 and older within the MARINER database were analyzed. Descriptive characteristics were calculated for all included patients. χ2 tests were used to compare categorical variables. P values < 0.05 were statistically significant.

RESULTS

A total of 45,542 procedures were conducted in the United States from 2010 to 2020 (clipping: 14,491; coiling: 28,840; flow diversion: 2211). The Southern United States had the largest operative volume across all 3 intervention types, closely followed by the Midwest. Aneurysms of the middle cerebral artery were mostly clipped, whereas coiling and flow diversion techniques were most utilized for anterior communicating and posterior communicating artery aneurysms. Flow diversion is growing most rapidly in the treatment of unruptured aneurysms, though there were also significant increases in usage for ruptured aneurysm treatment from 2019 to 2020.

CONCLUSIONS

Flow diverters have gained significant traction in the treatment for both unruptured and ruptured aneurysms. In the coming years, the indications and use of flow diversion will undoubtedly grow further, but excitement over their application should be tempered by the safety and efficacy data that continues to emerge.

Surgical Trapping of a Cavernous Carotid Aneurysm Causing Carotid Cavernous Fistula After Flow Diverter Placement: Technical Note and Literature Review

BACKGROUND

Flow diverter (FD) treatment is a promising therapeutic strategy for intracranial aneurysms such as cavernous carotid aneurysms (CCAs). Direct cavernous carotid fistula (CCF) caused by delayed rupture of FD-treated CCAs has been reported, and endovascular therapy has been used in the literature. Surgical treatment is warranted for patients who have failed or are ineligible for endovascular treatment. However, no studies have evaluated surgical treatment to date. Here, this paper presents the first case of direct CCF due to delayed rupture of an FD-treated CCA managed with surgical internal carotid artery (ICA) trapping with bypass revascularization, in which the intracranial ICA with FD placement was successfully occluded with aneurysm clips.

METHODS

A 63-year-old man with a diagnosis of large symptomatic left CCA underwent FD treatment. The FD was deployed from the supraclinoid segment of the ICA distal to the ophthalmic artery to the petrous segment of the ICA. Since angiography 7 months after the FD placement showed progressive direct CCF, left superficial temporal artery-middle cerebral artery bypass followed by ICA trapping was performed.

RESULTS

The intracranial ICA proximal to the ophthalmic artery where the FD was placed was successfully occluded using two aneurysm clips. The postoperative course was uneventful. Follow-up angiography 8 months after the surgery confirmed complete obliteration of the direct CCF and CCA.

CONCLUSIONS

The intracranial artery in which the FD was deployed was successfully occluded with two aneurysm clips. ICA trapping can be a feasible and useful therapeutic option to treat direct CCF caused by FD-treated CCAs.

Onset-to-treatment time and aneurysmal regression predict improvement of cranial neuropathy after flow diversion treatment in patients with symptomatic internal carotid artery aneurysms

BACKGROUND

Although flow diversion plays a pivotal role in treating internal carotid artery aneurysms presenting with cranial neuropathy, predictors of symptom improvement have not been established.

OBJECTIVE

To investigate improvement of symptoms after flow diversion treatment in patients with internal carotid artery aneurysms causing cranial neuropathy, with sufficient follow-up period. Additionally, to examine factors associated with improvement of symptoms.

METHODS

This retrospective multicenter study examined patients with unruptured internal carotid artery aneurysms presenting with cranial neuropathy who were treated using flow diversion and followed up for at least 12 months. Study outcomes were transient worsening of symptoms and symptom status 12 months after treatment. Patient and aneurysm characteristics were statistically analyzed.

RESULTS

Seventy-seven patients were included. Data needed for outcome analysis were available for 66 patients. At the 1-, 3-, 6-, 12-month, and last follow-ups, the proportion of patients with resolved or improved symptoms was 26% (20/77), 51% (39/77), 74% (57/77), 83% (64/77), and 79%(62/77), respectively. Symptom onset-to-treatment time <6 months (OR=24.2; 95% CI 3.09 to 188.84; p=0.002) and aneurysmal regression (OR=23.1; 95% CI 1.97 to 271.75; p=0.012) were significantly associated with symptom improvement. Transient symptom worsening and worse symptoms at 12 months occurred in 19/77 (25%) and 2/77 (3%) patients, respectively.

CONCLUSIONS

The rate of cranial neuropathy symptom improvement after flow diversion increased over the first 12 months after treatment, but not thereafter. Treatment within 6 months of symptom onset and aneurysmal regression were predictors of symptom improvement.

Complications after endovascular treatment of large basilar trunk aneurysms

BACKGROUND AND PURPOSE

Large basilar trunk aneurysms (BTAs) have a poor natural history if left untreated and always pose a significant challenge to endovascular treatment. The present study aimed to analyze the complications after endovascular treatment of large BTAs.

METHODS

This was a retrospective, observational, cohort study. Between January 2015 and September 2022, 9116 patients with intracranial aneurysms came to our institution for management, of which 34 patients with 34 large (≥10 mm) BTAs were treated with endovascular treatment. Postprocedural complications, clinical, and angiographic outcomes were evaluated.

RESULTS

All 34 patients (34 aneurysms) were successfully treated, of which 13 aneurysms were treated with flow diversion (FD), and 21 aneurysms were treated with stent-assisted coiling. Neurological complications occurred in 12 (35.3%) patients, with 7 (20.6%) deaths. Ischemic complications occurred in 10 (29.4%) patients, and 4 (11.8%) patients experienced hemorrhagic events. The incidences of favorable outcomes at discharge and last follow-up were 85.3% and 75.8%, respectively. The cumulative survival rates at 1 and 3 years were 86.5% and 71.4%, respectively. Unilateral vertebral artery sacrifice was associated with postprocedural complications (hazard ratio: 3.74, 95% confidence interval: 1.06-13.25, p = 0.041). The postprocedural complication rates were comparable between patients treated with FD and stent-assisted coiling (5/13, 38.5% vs. 7/21, 33.3%, p > 0.99). Angiography follow-up was available for 21 patients, and complete aneurysm occlusion was observed in 16/21 (76.2%) aneurysms.

CONCLUSIONS

Endovascular treatment might be a feasible option for treating large BTAs. However, clinicians should be alerted to procedure-related complications, especially ischemic complications that cause disability or death. Unilateral vertebral artery sacrifice might be associated with postprocedural complications.

External carotid artery-radial artery graft-posterior cerebral artery bypass for complex vertebrobasilar aneurysms: efficacy and analysis of outcome in a single center

The purpose of this research was to demonstrate the effectiveness and clinical outcome of an external carotid artery-radial artery graft-posterior cerebral artery (ECA-RAG-PCA) bypass in the treatment of complex vertebrobasilar artery aneurysms (VBANs) in a single-center retrospective study. An ECA-RAG-PCA bypass may be a last and very important option in the treatment of complex VBANs when conventional surgical clipping or endovascular interventions fail to achieve the desired outcome. This study retrospectively analyzed the clinical presentation, case characteristics, aneurysm location, size and morphology, choice of surgical strategy, complications, clinical follow-up, and prognosis of the patients enrolled. The data involved were analyzed by the appropriate statistical methods. A total of 24 patients with complex VBANs who met the criteria were included in this study. Eighteen (75.0%) were male and the mean age was 54.1 ± 8.83 years. The aneurysms were located in the vertebral artery, the basilar artery, and in the vertebrobasilar artery with simultaneous involvement. All patients underwent ECA-RAG-PCA bypass surgery via an extended middle cranial fossa approach, with 8 (33.3%) undergoing ECA-RAG-PCA bypass only, 3 (12.5%) undergoing ECA-RAG-PCA bypass combined with aneurysm partial trapping, and 12 (50.0%) undergoing ECA-RAG-PCA bypass combined with proximal occlusion of the parent artery. The average clinical follow-up was 22.0 ± 13.35 months. The patency rate of the high-flow bypass was 100%. At the final follow-up, 15 (62.5%) patients had complete occlusion of the aneurysm, 7 (29.2%) patients had subtotal occlusion of the aneurysm, and 2 (8.3%) patients had stable aneurysms. The rate of complete and subtotal occlusion of the aneurysm at the final follow-up was 91.7%. The clinical prognosis was good in 21 (87.5%) patients and no procedure-related deaths occurred. Analysis of the good and poor prognosis groups revealed a statistically significant difference in aneurysm size (P = 0.034, t-test). Combining the results of this study and the clinical experience of our center, we propose a surgical algorithm and strategy for the treatment of complex VBANs.The technical approach of ECA-RAG-PCA bypass for complex VBANs remains important, even in an era of rapid advances in endovascular intervention. When conventional surgical clipping or endovascular intervention has failed, an ECA-RAG-PCA bypass plays a role that cannot be abandoned and is a very important treatment option of last resort.

Safety and efficacy of pipeline embolization device treatments for intradural internal carotid artery aneurysms in a single center in a Japanese population

Background:

The pipeline embolization device (PED) is the most common flow diverter device in the world. To date, there have been no reports of treatment outcomes specific to intradural internal carotid artery (ICA) aneurysms. The safety and efficacy of the PED treatments for intradural ICA aneurysms are reported.

Methods:

131 patients with 133 aneurysms underwent PED treatments for intradural ICA aneurysms. The mean aneurysm dome size and neck length were 12.7 ± 4.3 mm and 6.1 ± 2.2 mm, respectively. We used adjunctive endosaccular coil embolization for 88 aneurysms (66.2%). A total of 113 aneurysms (85%) were angiographically followed up 6 months following the procedure, and 93 aneurysms (69.9%) were followed up for 1 year.

Results:

The angiographic outcome at 6 months showed that 94 (83.2%) aneurysms had O’Kelly-Marotta (OKM) grade D, 6 (5.3%) had C, 10 (8.8%) had B, and 3 (2.7%) had A. At 1 year, 82 (88.2%) aneurysms had OKM grade D, 6 (6.5%) had C, 3 (3.2%) had B, and 2 (2.2%) had A. Multivariate analysis showed that aneurysm neck size and adjunctive coiling were statistically significant in aneurysm occlusion status. Major morbidity modified Rankin Scale >2 and mortality rates related to procedures were 3.0% and 0%, respectively. Delayed aneurysm ruptures were not observed.

Conclusion:

These results reveal that PED treatment of intradural ICA aneurysms is safe and efficacious. The combined use of adjunctive coil embolization not only prevents delayed aneurysm ruptures but also contributes to an increase in the rate of complete occlusion.

Predictive Factors of Recurrence after Endovascular Treatment of Unruptured Vertebrobasilar Fusiform Aneurysms

PURPOSE

This study aimed to investigate the predictive factors of recurrence after endovascular treatment (EVT) for unruptured vertebrobasilar fusiform aneurysms (VBFA).

METHODS

This single-center retrospective study evaluated 36 patients who underwent EVT of unruptured VBFA between 2008 and 2020. Variables influencing recurrence, such as size, type, thrombus, preoperative symptoms, and treatment methods, were analyzed. All patients were followed up using vessel imaging.

RESULTS

In total, 7 of 36 patients (19.4%) developed recurrence. The mean time from EVT to recurrence was 9.2 months (range 2-26.9 months). Maximum aneurysmal diameter on magnetic resonance imaging was decreased, increased, and remained unchanged in 1, 7, and 28 patients, respectively. Transitional type VBFA, brain compression symptoms, large aneurysmal diameter and length, preoperative modified Rankin Scale (mRS) score ≥ 2, sole stenting technique, and intra-aneurysmal thrombus significantly influenced the risk of recurrence. Post-EVT, 7 (19.4%) patients showed complete occlusion of the aneurysm on the immediate postoperative angiogram, and 22 (61.1%) patients showed complete occlusion on the 1‑year follow-up imaging. Good outcomes were observed in 32 patients (88.9%) at the last follow-up, with a mRS score of 0-1 after EVT.

CONCLUSION

EVT achieves good outcomes in unruptured VBFA. Transitional type VBFA, brain compression symptoms, large aneurysmal diameter and length, preoperative mRS score ≥ 2, sole stenting technique, and intra-aneurysmal thrombus are risk factors for aneurysm recurrence after EVT.

Pipeline Flex with Shield Technology Placement for Small- and Medium-sized Aneurysms Achieves Early Complete Occlusion

The flow diverter has been shown to be a safe and effective device for large cerebral aneurysms in the proximal internal carotid artery (ICA). Recently, its indication has been expanded to small- and medium-sized cerebral aneurysms in the distal segment of the ICA. In this study, we report a single-center, retrospective investigation of the safety and efficacy of the Pipeline Flex device to treat these aneurysms. Of the patients who underwent Pipeline implantation for small- and medium-sized ICA aneurysms (≤12 mm) at our hospital between July 2013 and October 2021, 102 patients with 104 aneurysms were included in this study. The mean age of the patients was 57.7 ± 12.1 years, and 94 (90.4%) were female. The mean aneurysmal dome diameter was 9.2 ± 2.3 mm, the mean neck diameter was 5.3 ± 1.6 mm, and the mean dome-to-neck ratio was 1.8 ± 0.5. Twenty-five patients (24.0%) had incorporated vessels from the aneurysm. Complete occlusion of the aneurysms was obtained in 96 patients (92.3%). There were no cases of parent artery stenosis or major stroke after the procedure. Absence of incorporated vessel from the aneurysm dome and adjunctive coil embolization are statistically significant factors indicating complete occlusion in multivariate analysis. The time to complete occlusion was determined earlier with the use of the Pipeline Shield (p = 0.0386) and with adjunctive coils (p = 0.0025). We showed that Pipeline implantation for small- and medium-sized aneurysms was safe and highly effective.

LVIS-within-enterprise double-stent technique with coil embolization in the treatment of patients with acutely ruptured intracranial vertebrobasilar artery-dissecting aneurysms

Objective

This study aimed to evaluate the feasibility of the low-profile visualized intraluminal support (LVIS)-within-enterprise double-stent technique for patients with acutely ruptured intracranial vertebrobasilar artery-dissecting aneurysms (ari-VBDAs).

Methods

A total of 30 patients with ari-VBDAs who underwent reconstructive treatment using LVIS-within-enterprise double-stent technique with coil embolization between January 2014 and May 2022 were retrospectively enrolled. Patients' characteristics and clinical and imaging outcomes were reviewed. The functional outcomes were assessed using the modified Rankin scale (mRS).

Results

A total of 34 ari-VBDAs were identified, including seven (20.6%) basilar artery aneurysms and 27 (79.4%) vertebral artery aneurysms. All aneurysms were successfully treated in the acute phase. In total, six (20.0%) patients experienced in-hospital serious adverse events, including two deaths (6.7%). The median clinical follow-up time of the remaining 28 patients was 20.0 (IQR, 7.3-40.8) months. The incidences of dependency or death (mRS score of 3-6) at discharge and at the last follow-up were 16.7% and 14.3%, respectively. Aneurysm rebleeding occurred in one (3.3%) patient periprocedurally. In total, three (10.0%) patients had ischemic events, one of which occurred during the periprocedural period and two occurred during follow-up. A total of two patients (6.7%) underwent ventriculoperitoneal shunt. Imaging follow-up was available for 14 patients at the median of 12.0 (IQR, 7.0-12.3) months, with a complete occlusion rate of 93.3% (14/15). In total, one patient experienced parent artery occlusion, and no aneurysm was recanalized.

Conclusion

LVIS-within-enterprise double-stent technique with coil embolization for the treatment of patients with ari-VBDAs could be performed with a good safety profile and high technical success rate. The rate of complete aneurysm occlusion during follow-up seemed to be satisfactory.

Coiling followed by staged flow diversion for large and giant intracranial aneurysms

Objective

Delayed aneurysm rupture is a fatal complication after flow diversion treatment for large and giant intracranial aneurysms. This study aimed to investigate the feasibility and safety of coiling first and followed by planned flow diversion to prevent delayed aneurysm rupture.

Methods

From January 2017 to December 2021 in two institutions, patients with unruptured intracranial aneurysms treated by coiling first and planned flow diversion were retrospectively collected. Data on demographic and aneurysmal characteristics, procedural details, and clinical and angiographic outcomes were reviewed.

Results

Thirty patients were included (7 Males and 23 Females; Median age 57 years). Aneurysmal size ranged from 11.8 to 26.8 mm, with a median value of 18.5 mm. All aneurysms were located within the intradural segment of internal carotid arteries. Coiling and planned flow diversion were successfully performed in all patients. The time interval between coiling and flow diversion was 3.9–6.7 weeks, with a median value of 5.2 weeks. No hemorrhagic or ischemic complications occurred during the procedures and follow-up. Complete or subtotal occlusion was achieved in 86.7% (26/30) at the last angiographic follow-up (median 6.7 months).

Conclusion

The preliminary data suggested that coiling unruptured intracranial aneurysms followed by planned flow diversion is both safe and effective. Further studies with larger cohorts are needed to verify the effect of this new strategy in preventing delayed rupture after flow diversion.

Pipeline for the treatment of distal cerebral circulation aneurysms: A multicenter study focusing on periprocedural Complications

BACKGROUND AND AIM

Distal cerebral circulation aneurysms (DCCAs) remain treatment challenges for neurointervention. The off-label use of the pipeline embolization device (PED) for these aneurysms remains controversial. This study aimed to evaluate the safety and efficacy of PED for DCCAs in a multicenter cohort of patients.

METHODS

Between March 2016 and June 2021, we retrospectively analyzed the neurointerventional data on the clinical and radiological records of all patients undergoing PED treatment of DCCAs at three medical centers.

RESULTS

A total of 53 consecutive patients with 53 DCCAs were treated with PED. The mean aneurysm size was 12.3 ± 5.7 mm. In total, 75.4% (40/53) were fusiform and 24.5% (13/53) were saccular. Of these, 17.0% (9/53) were recurrent aneurysms that were previously treated with endovascular or microsurgical approaches. The technical success rate was 100%, among which 81.1% (43/53) procedures were completed with a single PED, and the rest (10/53, 18.8%) required telescoping with two devices. Angiographic follow-up data were available for 51 patients, with a median follow-up time of 12 months. At the latest follow-up, 46/51 (90.2%) aneurysms showed complete obliteration, and 4/51 (7.8%) showed reduced filling. Periprocedural complications such as hemorrhage were observed in two patients with MCA aneurysms (3.8%, 2/53), and ischemic events occurred in six patients (11.3%, 6/53). The overall mortality and morbidity rates were 7% (4/53).

CONCLUSIONS

PED is a viable option for treating DCCAs, especially for recurrent aneurysms. Coverage of bifurcation branches and perforator may increase the risk of complications.

Case report: Covered stent placement to treat delayed aneurysmal rupture after flow diverter-assisted coil embolization

INTRODUCTION

Flow diverter (FD) placement is widely accepted as a treatment for large saccular intracranial aneurysms. Delayed aneurysmal rupture (DAR) after FD placement is potentially catastrophic and difficult to treat. To our knowledge, using a Willis covered stent (WCS) to treat DAR after placement of a Pipeline Flex embolization device (PFED) combined with coiling has not been previously reported.

CASE PRESENTATION

A 49-year-old woman with an incidental asymptomatic large right supraclinoid internal carotid artery aneurysm was treated with PFED placement and adjunctive coiling. DAR causing subarachnoid hemorrhage occurred 11 hours after the procedure. Treatment using a WCS was successful and resulted in a favorable clinical outcome (modified Rankin scale score 2).

CONCLUSION

DAR after FD implantation requires isolation of the aneurysm from the cerebral circulation as soon as possible. WCS placement can achieve this immediately and occlude the aneurysm. We hope our case could provide new idea for similar cases in the future.

Delayed aneurysm rupture in a patient treated with flow redirection endoluminal device: A case report and literature review

Background:

Delayed aneurysm rupture after flow-redirection endoluminal device (FRED) implantation is rare. We report a case of internal carotid-cavernous fistula (CCF) caused by a delayed aneurysm rupture of the cavernous portion of the internal carotid artery (ICA) after FRED implantation.

Case Description:

A 75-year-old woman had a gradually enlarging aneurysm at the C4 portion of the left ICA. We performed FRED implantation for the same. The FRED implantation procedure was smooth and the FRED expanded well and attached to the vessel wall. Five days after surgery, the patient developed a strong headache, hyperemia of the left eye, and disturbance of the left eye movement. Magnetic resonance imaging and angiography revealed a left CCF with cortical venous reflux. We performed transarterial aneurysmal and transvenous cavernous sinus embolization. Postoperatively, angiography showed no fistula and complete occlusion of the aneurysm; however, minor eye movement disorder persisted.

Conclusion:

To prevent the development of delayed aneurysm rupture in patients treated with FRED, preoperative consideration of whether to add coil embolization is important, even if the aneurysm is located in the C4 portion of the ICA and there is no risk of subarachnoid hemorrhage, including the size of aneurysm. In this report, we have tried to alert surgeons regarding the risk of delayed aneurysm rupture due to FRED implantation.

Time Line of Occlusion for Intracranial Aneurysms Treated with the Pipeline Embolization Device

BACKGROUND

Rates of aneurysm occlusion following treatment with flow-diverting stents have been quantified at predefined time points in clinical trials, but data characterizing the continuous temporal progression of aneurysm occlusion are lacking. This study used real-world variability in timing of angiographic follow-up to characterize the time line of aneurysm occlusion following treatment with the Pipeline embolization device (PED).

METHODS

All aneurysms treated with a PED at our institution between 2011 and 2020 were screened. Nonsaccular or ruptured aneurysms were excluded. Aneurysm occlusion status and time since treatment were recorded for each follow-up angiogram. Aneurysm occlusion was characterized using Kaplan-Meier and Cox proportional hazards analysis after censoring at last follow-up or subsequent treatment.

RESULTS

There were 290 aneurysms in 222 patients analyzed. The median time of observed aneurysm occlusion was 7.5 months, and overall rate of aneurysm occlusion was 77.9%. Larger aneurysms demonstrated a longer median time to occlusion and lower rate of aneurysm occlusion (P = 0.029). There were no observed differences in the time line of occlusion for aneurysms treated with a single PED or multiple PEDs (P = 0.889) or without or with adjunctive coiling (P = 0.771).

CONCLUSIONS

Aneurysms treated with a PED had a median time to observed occlusion of 7.5 months. Occlusion of larger aneurysms occurred more slowly than occlusion of smaller aneurysms following flow diversion. The number of PEDs deployed or the use of adjunctive coiling did not affect the time line or likelihood of aneurysm occlusion. These findings may guide optimal timing of follow-up after treatment with a PED.

Predictors of unfavorable outcome in stent-assisted coiling for symptomatic unruptured intracranial spontaneous vertebral artery dissecting aneurysms (uis-VADAs): results from a multicenter study

OBJECTIVE

To evaluate predictors of unfavorable outcome in stent-assisted coiling for symptomatic unruptured intracranial spontaneous vertebral artery dissecting aneurysms (uis-VADAs) based on 608 reconstructed lesions in 30 medical centres.

METHODS

A total of 608 patients (male:female=479:129; mean age, 53.26±10.26 years) with 608 symptomatic uis-VADAs underwent reconstructive treatments using stent(s) with coils between January 2009 and December 2015. Treatments and predictors of unfavorable outcomes were retrospectively analyzed.

RESULTS

Mainly, three methods were used to treat patients with uis-VADAs, including routine single-stent in 208 patients (such as Enterprise and others), new low-profile LVIS single stent in 107 patients, and multiple stents in 293 patients. During the median 66 months of clinical follow-up, 14 patients died, and 16 of the remaining 594 survivors had unfavorable outcomes (modified Rankin Scale score 3-5). The overall mortality rate was 2.3% (14/608), and the unfavorable outcome (mRS score 3-6) rate was 4.9% (30/608). Multivariate logistic regression analysis indicated that preprocedural ischemic infarctions (OR=3.78; 95% CI 1.52 to 9.40; p<0.01), diabetes mellitus (OR=3.74; 95% CI 1.31 to 10.68; p=0.01), and procedural complications (OR=14.18; 95% CI 5.47 to 36.80; p<0.01) were predictors of unfavorable outcome in the reconstructed VADAs.

CONCLUSIONS

This multicenter study indicated that preprocedural ischemic infarctions, diabetes mellitus, and procedural complications were related to unfavorable clinical outcomes in the reconstructed uis-VADAs.

Preliminary Experience of the Surpass Streamline Flow Diverter for Large and Giant Unruptured Internal Carotid Artery Aneurysms

As of January 2021, the Surpass Streamline (SS) is the most recently approved flow diverter in Japan. A total of 28 Japanese patients, including 9 clinical trial patients, with 28 large or giant unruptured internal carotid artery (ICA) aneurysms, underwent SS embolization at Juntendo University Hospital. Procedural failure occurred in two patients due to the difficulty to navigate the device in the tortuous parent artery. Therefore, 26 patients with 26 aneurysms were available for clinical and anatomical assessments. Patients' mean age was 62.6 years (range 46-86), and 24 patients (92.3%) were female. Mean aneurysm size and neck width were 15.4 mm and 7.7 mm, respectively, with 20 saccular and 6 fusiform aneurysms. Seven aneurysms were symptomatic due to the aneurysmal mass effect. Twenty patients underwent a 6-month follow-up angiography to evaluate the degree of occlusion. Anatomical outcomes were 12 (60%) complete occlusion (CO), 4 (20%) residual neck (RN), and 4 (20%) residual aneurysm. Favorable aneurysm occlusion consisted of CO, and RN was achieved in 16 (80.0%). There were no significant device stenoses. Aneurysmal mass effect improved in one and was unchanged in eight patients. There were three device-related complications, namely, delayed aneurysm rupture, minor ischemic stroke, and device occlusion (11.5%). One patient with minor ischemic stroke fully recovered before 30 days, and our series showed 7.7% risk of major ipsilateral stroke and neurological death at 30 days. The SS embolization for large and giant unruptured ICA aneurysms offers satisfactory anatomical and clinical outcomes with a low risk of device-related complications.