Review of 2 decades of aneurysm-recurrence literature, part 2: Managing recurrence after endovascular coiling

Efficacy of Coil Embolization in Small, Anterior Circulation Aneurysms in Patients Less Than 40 Years Old

Background: Ruptured and unruptured aneurysms are less common in younger individuals compared to older patients. Endovascular treatment has gained popularity over surgical options in the general population, but surgery remains the primary treatment for younger patients due to concerns about higher recurrence rates with endovascular procedures. Methods: This study compared the immediate and long-term outcomes of endovascular treatment in patients under 40 years with those aged 41-60. The study included 239 patients who underwent endovascular treatment for intracranial aneurysms, divided into two age groups: under 40 and 41-60 years. The rates of immediate radiologic outcomes, complications, and recurrence were assessed. Results: The results showed successful aneurysm obliteration rates of 70.1% in the younger group and 64.0% in the older group. The complication rates were 1.5% in the younger group and 3.5% in the older group, with the older group experiencing more procedure-related complications, though this difference was not statistically significant. Long-term follow-up revealed recurrence rates of 23.2% in the younger group and 18.2% in the older group, with no significant difference. Conclusions: The study suggests that endovascular treatment is as effective and safe for patients under 40 years. Therefore, it may be considered an acceptable first-line treatment for younger patients, aligning its use with that in older populations.

Neqstent coil-assisted flow diverter (NQS) for the treatment of bifurcation aneurysms: the coil-assisted flow diversion safety and performance study (CAFI)

BackgroundThe Neqstent coil-assisted flow diverter (NQS) is a neck bridging device to facilitate coil occlusion of intracranial aneurysms. CAFI is a prospective, single-arm, multicenter study on the safety and performance of the NQS adjunctive therapy device together with platinum coils for treatment of unruptured intracranial aneurysms.

METHODS

Thirty-eight patients were enrolled. Primary endpoints were occlusion at 6 months for efficacy, and any major stroke or non-accidental death up to 30 days or major disabling stroke within 6 months for safety. Secondary endpoints were re-treatment rate, procedure time, and procedure/device-related adverse events. Procedural and follow-up imaging was reviewed by an independent core laboratory. Adverse events were reviewed and adjudicated by a clinical events committee.

RESULTS

The NQS was successfully implanted in 36/38 aneurysms, 2/38 in the intention-to-treat group did not receive a NQS and were excluded from follow-up after 30 days. In the per protocol group (PP), 33/36 patients were available for angiographic follow-up. Device related adverse events were recorded in 4/38 (10.5%) patients, one hemorrhagic and three thromboembolic. In the PP group, immediate post-treatment adequate occlusion (RR1 and RR2) was seen in 9/36 (25%) and progressed to 28/36 (77.8%) at 6 months. Complete occlusion (RR1) was achieved in 29/36 (80.6%) at the last available angiogram (3/36 were post procedure). The mean procedure time was 129 min (50-300 min, median 120 min).

CONCLUSION

The NQS in conjunction with coils appears to be effective in the treatment of intracranial wide-neck bifurcation aneurysms, but its safety remains to be proved in larger series.

TRIAL REGISTRATION NUMBER

NCT04187573.

Long-Term Follow-Up of Cerebral Aneurysms Completely Occluded at 6 Months After Intervention with the Woven EndoBridge (WEB) Device: a Retrospective Multicenter Observational Study

The Woven EndoBridge (WEB) device has been widely used to treat intracranial wide neck bifurcation aneurysms. Initial studies have demonstrated that approximately 90% of patients have same or improved long-term aneurysm occlusion after the initial 6-month follow up. The aim of this study is to assess the long-term follow-up in aneurysms that have achieved complete occlusion at 6 months. We also compared the predictive value of different imaging modalities used. This is an analysis of a prospectively maintained database across 13 academic institutions. We included patients with previously untreated cerebral aneurysms embolized using the WEB device who achieved complete occlusion at first follow-up and had available long-term follow-up. A total of 95 patients with a mean age of 61.6 ± 11.9 years were studied. The mean neck diameter and height were 3.9 ± 1.3 mm and 6.0 ± 1.8 mm, respectively. The mean time to first and last follow-up was 5.4 ± 1.8 and 14.1 ± 12.9 months, respectively. Out of all the aneurysms that were completely occluded at 6 months, 84 (90.3%) showed complete occlusion at the final follow-up, and 11(11.5%) patients did not achieve complete occlusion. The positive predictive value (PPV) of complete occlusion at first follow was 88.4%. Importantly, this did not differ between digital subtraction angiography (DSA), magnetic resonance angiography (MRA), or computed tomography angiography (CTA). This study underlines the importance of repeat imaging in patients treated with the WEB device even if complete occlusion is achieved short term. Follow-up can be performed using DSA, MRA or CTA with no difference in positive predictive value.

Stent-assistant versus non-stent-assistant coiling for ruptured and unruptured intracranial aneurysms: A meta-analysis and systematic review

Background

Several different endovascular and non-invasive treatment methods are suggested for the various types of intracranial aneurysms including simple, balloon-assisted, and stent-assisted coiling (SAC). Previous studies investigated the safety and efficacy of SAC versus non-stent-assisted coiling (non-SAC) but the results were controversial. We aim to perform a systematic review and meta-analysis to compare the efficacy and safety of SAC with non-SAC technique in stratifying by the ruptured and unruptured aneurysms.

Methods

PubMed, Scopus, Web of Science, and Cochrane Central Register of Controlled Trials were searched in April 2022 for studies investigated the efficacy and safety of SAC versus non-SAC.

Results

Overall, 26 studies entered into our qualitative and quantitative synthesis. We found that there was overall lower recurrence rate in SAC versus non-SAC significant (RR: 0.43, 95%CI: 0.33, 0.53). Furthermore, the comparisons were significant in unruptured (RR: 0.63, 95%CI: 0.40, 0.86), ruptured (RR: 0.29, 95%CI), and combination aneurysms (RR: 0.42, 95%CI: 0.30, 0.54). Also, we found higher risk of intraprocedural rupture for SAC versus non-SAC in unruptured aneurysms (RR: 1.40, 95%CI: 1.31, 1.50). Investigating hemorrhagic events risk showed that there was significant difference in ruptured (RR: 1.73, 95%CI: 1.12, 2.34) and combination aneurysms (RR: 0.60, 95%CI: 0.37, 0.82). There was no significant difference in immediate occlusion rate, complete occlusion, and risk of ischemic events in our analysis.

Conclusion

Overall, our findings demonstrated that SAC may have higher efficacy in term of recurrence rate, but also may have a higher risk of complications in the treatment of intracranial aneurysms. As there are several factors affecting the outcomes and safety of these interventions, further RCTs controlled for multiple factors are required better guide the neurointerventionists choose the best strategy.

Co-occurrence of Meningioma and Intracranial Aneurysm: A Systematic Review

A complete understanding of the rare neurosurgical phenomenon of co-occurring meningioma and intracranial aneurysm is important to improve the quality of life and decrease future complications in these patients. In this review, we searched the literature for cases of this rare phenomenon to highlight the most important historical, investigation, and treatment-related factors to improve the accuracy of intraoperative procedural decisions. We searched the PubMed database for case reports on this neurological rare phenomenon to create organized data for our review. Then, we extracted information from these cases and organized it in a table. We identified 19 cases in the literature. In the published studies, there was a predominance of the female sex (73.68%). The mean age of the patients was 54.11 years, with the cases relatively evenly distributed among patients in their 30s, 40s, 50s, 60s, and 70s. Posterior communicating artery aneurysm was the most common among the 19 cases. For meningioma, the frontal lobe and clinoid were the two most affected locations, and the meningothelial histopathology was the most common. Complete tumor resection and aneurysmal clipping were done for the majority of the cases (57.8%) unless there was a complication that deferred simultaneous intervention. Fortunately, most patients (78.95%) recovered completely after surgery. The coexistence of meningioma and intracranial aneurysm has a very high cure rate, postoperative symptom resolution, and a very low recurrence rate. For most cases, neuroimaging investigations are recommended for simultaneous management. This imaging can also highlight other potentially suspicious findings.

Target Ultra and Nano coils in the endovascular treatment of small intracranial aneurysms (ULTRA Registry)

OBJECTIVE

The ULTRA Registry is a national multicenter prospective study designed to assess aneurysm occlusion rates and safety profiles of the Target Ultra and Nano coils in the treatment of small intracranial aneurysms (IAs).

METHODS

Patients with small (≤ 5 mm) ruptured and unruptured IAs were treated exclusively with Target Ultra and Nano coils. The primary endpoints were the initial rate of complete or near-complete aneurysm occlusion, aneurysm recurrence, and need for retreatment. Secondary endpoints were device- and procedure-related adverse events, hemorrhage from the coiled aneurysm at any time during follow-up, and clinical outcomes.

RESULTS

The ULTRA Registry included 100 patients with a mean ± SD age of 56 ± 11.6 years, of whom 75 were women and 48 presented after aneurysm rupture. The mean aneurysm size was (3.5 ± 0.9) × (2.8 ± 0.9) × (3.0 ± 1.0) mm, and the mean packing density was 34.4% ± 16.7%. Posttreatment complete or near-complete occlusion reported by an independent imaging core laboratory was seen in 92% of patients at baseline and in 87%, 87%, and 83% of patients at first, second, and final follow-up, respectively. At first, second, and final follow-up, 10%, 11%, and 15%, respectively, of patients were deemed to require retreatment. There were three procedural-related ischemic strokes and one intracranial hemorrhage from wire perforation of a parent artery not involved by the aneurysm. There were no coil-related adverse events, including no intraoperative aneurysm ruptures and no known aneurysm ruptures after coiling.

CONCLUSIONS

This assessment of aneurysm occlusion rates and safety profiles in ULTRA Registry study participants demonstrates excellent safety and efficacy profiles for Target Ultra and Nano coils in the treatment of small IAs.

Intrasaccular flow disruption for brain aneurysms: a systematic review of long-term outcomes

OBJECTIVE

The long-term safety and efficacy of intrasaccular flow disruption (IFD) for the treatment of brain aneurysms remain unclear. With accumulating experience and increasing use of IFD devices, recent studies have provided additional data regarding their outcomes. This review summarizes the long-term outcomes of IFD-treated brain aneurysms.

METHODS

A systematic literature review was performed on May 23, 2021, in PubMed, Web of Science, and Ovid MEDLINE for aneurysm treatment outcomes with IFD devices. Procedural details, including use of adjunctive devices and complications, were collected. The quality of studies was assessed using the Downs and Black checklist. Angiographic outcomes were classified as complete occlusion, residual neck, and residual aneurysm. Other outcomes included need for retreatment, permanent neurological deficit, and mortality. Pooled analyses were performed.

RESULTS

The final analysis comprised 1217 patients with 1249 aneurysms from 22 studies. The mean aneurysm diameter and neck width were 6.9 and 4.5 mm, respectively, and 27.6% of aneurysms were ruptured. The complete occlusion rates at 12 months and final follow-up (pooled mean duration 15.7 months) were 50.1% and 58.2%, respectively. Adjunctive devices were used in 6.4% of cases. The rates of hemorrhage, symptomatic infarction, permanent neurological deficit, and mortality were 1.2%, 2.8%, 1.0%, and 2.6%, respectively.

CONCLUSIONS

IFD is a very safe treatment for appropriately selected brain aneurysms with low complication and neurological deterioration rates. However, complete occlusion is achieved in only half of IFD-treated aneurysms at 1 year with a modest increase beyond this time point. As the majority of the studies were single arm, the pooled data are subject to selection and reporting biases. Future device developments, increased operator experience, and direct comparisons with alternative endovascular strategies and surgical clipping may clarify the role of IFD in aneurysm management.

Delayed rupture of an anterior communicating artery aneurysm after elective Woven EndoBridge embolization, re-treated with microsurgical clipping: operative technique and systematic review

BACKGROUND

The Woven EndoBridge (WEB) device is designed for intrasaccular flow disruption for embolization of intracranial aneurysms. In limited experience so far, the rate of rupture after adequate occlusion by embolization is low.

TECHNICAL REPORT

A 58-year-old man initially had an incidental, unruptured 10.4 mm anterior communicating artery (ACoA) aneurysm treated with WEB embolization. Although his 6-month follow-up angiogram showed adequate occlusion of the aneurysm, he presented to our facility with aneurysmal recurrence due to WEB compaction and rupture. This was treated with surgical clipping of the aneurysm.

METHODS

The literature was systematically reviewed for cases of delayed rupture after WEB embolization. Statistical analyses included studies with at least 20 patients and follow-up of 3 months.

RESULTS

We identified 36 studies, which were primarily retrospective observational studies. The rate of complete occlusion ranged from 33% to 89%, and the rate of re-treatment ranged from 1.5% to 27%. Across four studies, the rate of recanalization ranged from 8.7% to 13%. Two cases of delayed rupture were reported; an additional four cases were found in case reports and case series. In only one previous case, the aneurysm was reported as previously untreated.

CONCLUSION

Early retrospective data has begun to define the history of WEB-treated aneurysms. Rupture of a previously unruptured, WEB-treated aneurysm with adequate initial occlusion is rare. We describe such a case with techniques for management, demonstrating that aneurysm recurrence and delayed rupture is possible despite good interim angiographic result. This report raises questions about follow-up for WEB-treated aneurysms.

Can further subdivision of the Raymond-Roy classification of intracranial aneurysms be useful in predicting recurrence and need for future retreatment following endovascular coiling?

Background:

The Raymond-Roy classification has been the standard for neck recurrences following endovascular coiling with three grades. Several modified classification systems with subdivisions have been reported in literature but it is unclear whether this adds value in predicting recurrence or retreatment. Our aim is to assess if these subdivisions aid in predicting recurrence and need for retreatment.

Methods:

A retrospective review of all patients undergoing endovascular coiling between 2013 and 2014. Patients requiring stent assistance or other embolization devices were excluded from the study. The neck residue was graded at time of coiling on the cerebral angiogram and subsequent 6, 24, and 60 months MRA. Correlation between grade at coiling and follow-up with need for subsequent retreatment was assessed.

Results:

Overall, 17/200 (8.5%) cases required retreatment within 5 years of initial coiling. 4/130 (3.1%) required retreatment within 5 years with initial Grade 0 at coiling, 6/24 cases (25%) of those Grade 2a, 4/20 cases (20%) Grade 2b, 3/8 (38%) Grade 3, and none of those with Grade 1. Large aneurysms ≥11 mm had an increased risk of aneurysm recurrence and retreatment. About 9.7% of ruptured aneurysms required retreatment versus 4.4% for unruptured. About 55% of carotid ophthalmic aneurysms were retreated.

Conclusion:

Although the modified classification system was significantly predictive of progressive recurrence and need for retreatment, no significant difference between the subdivisions of Grade 2 was observed. Similar predictive value was seen when using the Raymond-Roy classification compared to the new modified, limiting the usefulness of the new system in clinical practice.

Macrophage activation in response to shape memory polymer foam-coated aneurysm occlusion devices

Brain aneurysms can be treated with embolic coils using minimally invasive approaches. It is advantageous to modulate the biologic response of platinum embolic coils. Our previous studies demonstrated that shape memory polymer (SMP) foam coated embolization coils (FCC) devices demonstrate enhanced healing responses in animal models compared with standard bare platinum coil (BPC) devices. Macrophages are the most prevalent immune cell type that coordinate the greater immune response to implanted materials. Hence, we hypothesized that the highly porous SMP foam coatings on embolic coils activate a pro-regenerative healing phenotype. To test this hypothesis, we analyzed the number and type of infiltrating macrophages in FCC or BPC devices implanted in a rabbit elastase aneurysm model. FCC devices elicited a great number of infiltration macrophages, skewed significantly to a pro-regenerative M2-like phenotype 90 days following implantation. We devised an in vitro assay, where monocyte-derived macrophages were placed in close association with FCC or BPC devices for 6-72 h. Macrophages encountering SMP FCC-devices demonstrated highly mixed activation phenotypes at 6 h, heavily skewing toward an M2-like phenotype by 72 h, compared with macrophages encountering BPC devices. Macrophage activation was evaluated using gene expression analysis, and secreted cytokine evaluation. Together, our results demonstrate that FCC devices promoted a pro-regenerative macrophage activation phenotype, compared with BPC devices. Our in vitro findings corroborate with in vivo observations that SMP-based modification of embolic coils can promote better healing of the aneurysm site, by sustaining a pro-healing macrophage phenotype.

Development and assessment of machine learning models for predicting recurrence risk after endovascular treatment in patients with intracranial aneurysms

Intracranial aneurysms (IAs) remain a major public health concern and endovascular treatment (EVT) has become a major tool for managing IAs. However, the recurrence rate of IAs after EVT is relatively high, which may lead to the risk for aneurysm re-rupture and re-bleed. Thus, we aimed to develop and assess prediction models based on machine learning (ML) algorithms to predict recurrence risk among patients with IAs after EVT in 6 months. Patient population included patients with IAs after EVT between January 2016 and August 2019 in Hunan Provincial People's Hospital, and an adaptive synthetic (ADASYN) sampling approach was applied for the entire imbalanced dataset. We developed five ML models and assessed the models. In addition, we used SHapley Additive exPlanations (SHAP) and local interpretable model-agnostic explanation (LIME) algorithms to determine the importance of the selected features and interpret the ML models. A total of 425 IAs were enrolled into this study, and 66 (15.5%) of which recurred in 6 months. Among the five ML models, gradient boosting decision tree (GBDT) model performed best. The area under curve (AUC) of the GBDT model on the testing set was 0.842 (sensitivity: 81.2%; specificity: 70.4%). Our study firstly demonstrated that ML-based models can serve as a reliable tool for predicting recurrence risk in patients with IAs after EVT in 6 months, and the GBDT model showed the optimal prediction performance.

Knowledge framework and emerging trends in intracranial aneurysm magnetic resonance angiography: a scientometric analysis from 2004 to 2020

Background

As magnetic resonance angiography (MRA) has been increasingly used in the follow-up of intracranial aneurysms (IAs) as a non-invasive technique, the knowledge framework and areas of research interest in intracranial aneurysms magnetic resonance angiography (IAMRA) change approximately every 10 years. However, few studies have quantitatively analyzed the published literature in this field. In the present study, we used scientometrics to survey the knowledge field, development trends, and research focus of IAMRA with the aim of providing a reference for further study.

Methods

We collected articles on IAMRA published from 2004 (Jan 1, 2004) to 2020 (May 24, 2020). Web of Science Core Collection databases (WoSCCd) including the Science Citation Index Expanded were searched. An experienced staff member from the Department of Radiology at Southern Medical University, assisted in screening articles for relevant articles. We used ArcGIS (a mapping and location analytics platform) to perform geographic visualization. Excel 2016 was used to analyze the literature data, including number of publications, impact factor (IF), and publication year. CiteSpace V was used to conduct a series of literature feature clustering, including author co-citation analysis, reference co-citation analysis (RCA), and burst keywords analysis.

Results

A total of 1,272 articles on IAMRA published between 2004 and 2020 were included. Of 257 journals, American Journal of Neuroradiology (IF 2018: 3.256) published the most IAMRA articles (109 publications, 8.57%), followed by Journal of Neurosurgery (IF 2018: 4.131, 51 publications, 4.16%), and Neuroradiology (IF 2018: 2.504, 51 publications, 4.01%). Of 56 countries, the USA published the most, with 347 articles [27.28%, IF: 3.14 (average IF of all journals in the country)], followed by Japan (242 articles, 19.03%, IF: 2.38), Germany (135 articles, 10.61%, IF: 3.21), and China (101 articles, 7.94%, IF: 2.86). A total of 1387 institutions published articles, with the Mayo Clinic publishing the most (33 articles, 2.59%), followed by Shanghai Jiao Tong University (25 article, 1.97%), Seoul National University (23 articles, 1.81%), and University Medical Center Utrecht (19 articles, 1.49%). Of 399 authors, Rinkel ranked first with 19 articles, followed by Li MH (18 articles), Uchino A (15 articles), and Saito N (13 articles). Cluster RCA showed that the first cluster was "#0 growth", followed by "#1 Guglielmi detachable coils". Timeline views showed that the time span of "#0 growth" was the closest to today. The modularity value was 0.6971, and the mean silhouette value was 0.5477. According to the burst keyword analysis, "risk factors associated to rupture" was the topic with the strongest burst since 2017. Studies conducted in several countries suggested that age is inversely related to the risk of rupture, which implies the importance of MRA follow-up for patients of different age.

Conclusions

From 2004 to 2020, the number of published IAMRA-related articles gradually increased. The USA and Western Europe lead in the field, with a concentration of cutting-edge talents and high-level scientific research institutions. A synthesis of the clustering results of RCA and burst keyword analysis indicated that unruptured IA growth, stent-assisted coil embolization, and risk factors associated to rupture were the current hotspots in IAMRA research.

Comprehensive review of imaging of intracranial aneurysms and angiographically negative subarachnoid hemorrhage

Intracranial aneurysms confer the risk of subarachnoid hemorrhage (SAH), a potentially devastating condition, though most aneurysms will remain asymptomatic for the lifetime of the patient. Imaging is critical to all stages of patient care for those who harbor an unruptured intracranial aneurysm (UIA), including to establish the diagnosis, to determine therapeutic options, to undertake surveillance in patients who elect not to undergo treatment or whose aneurysm(s) portends such a low risk that treatment is not indicated, and to perform follow-up after treatment. Neuroimaging is equally as important in patients who suffer an SAH. DSA remains the reference standard for imaging of intracranial aneurysms due to its high spatial and temporal resolution. As noninvasive imaging technology, such as CTA and MRA, improves, the diagnostic accuracy of such tests continues to increasingly approximate that of DSA. In cases of angiographically negative SAH, imaging protocols are necessary not only for diagnosis but also to search for an initially occult vascular lesion, such as a thrombosed, ruptured aneurysm that might be detected in a delayed fashion. Given the crucial role of neuroimaging in all aspects of care for patients with UIAs and SAH, it is incumbent on those who care for these patients, including cerebrovascular neurosurgeons, interventional neurologists and neuroradiologists, and diagnostic radiologists and neurointensivists, to understand the role of imaging in this disease and how individual members of the multispecialty team use imaging to ensure best practices to deliver cutting-edge care to these often complex cases. This review expounds on the role of imaging in the management of UIAs and ruptured intracranial aneurysms and in the workup of angiographically negative subarachnoid hemorrhage.

Definitive Treatment With Microsurgical Clipping After Recurrence and Rerupture of Coiled Anterior Cerebral Artery Aneurysms

BACKGROUND

The extent of obliteration of ruptured intracranial aneurysms treated with coil embolization has been correlated with the risk of rerupture. However, many practitioners consider that a small neck remnant is unlikely to result in significant risk after coiling.

OBJECTIVE

To report our recent experience with ruptured anterior cerebral artery aneurysms treated with endovascular coiling, which recurred or reruptured, requiring microsurgical clipping for subsequent treatment.

METHODS

Retrospective review of patients with intracranial aneurysms treated at our institution since August 2018. Patient and aneurysm characteristics, initial and subsequent treatment approaches, and outcomes were reviewed.

RESULTS

Six patients were included. Out of those 6 patients, 5 patients had anterior communicating artery aneurysms, and 1 patient had a pericallosal aneurysm. All initially presented with subarachnoid hemorrhage (SAH) and were treated with coiling. Recurrence occurred at a median of 7.5 mo. In 2 cases, retreatment was initially performed with repeat endovascular coiling, but further recurrence was observed. Rerupture from the residual or recurrent aneurysm occurred in 3 cases. In 2 cases, the aneurysm dome recurred; in 1 case, rerupture occurred from the neck. All 6 patients underwent treatment with microsurgical clipping. Follow-up catheter angiography demonstrated a complete occlusion of the aneurysm in all cases with the preservation of the parent vessel.

CONCLUSION

Anterior cerebral artery aneurysms may recur after endovascular treatment, and even small neck remnants present a risk of rerupture after an initial SAH. Complete treatment requires a complete exclusion of the aneurysm from the circulation. Even in cases that have been previously coiled, microsurgical clipping can represent a safe and effective treatment option.

Is 3 years adequate for tracking completely occluded coiled aneurysms?

OBJECTIVE

The authors conducted a study to ascertain the long-term durability of coiled aneurysms completely occluded at 36 months' follow-up given the potential for delayed recanalization.

METHODS

In this retrospective review, the authors examined 299 patients with 339 aneurysms, all shown to be completely occluded at 36 months on follow-up images obtained between 2011 and 2013. Medical records and radiological data acquired during the extended monitoring period (mean 74.3 ± 22.5 months) were retrieved, and the authors analyzed the incidence of (including mean annual risk) and risk factors for delayed recanalization.

RESULTS

A total of 5 coiled aneurysms (1.5%) occluded completely at 36 months showed recanalization (0.46% per aneurysm-year) during the long-term surveillance period (1081.9 aneurysm-years), 2 surfacing within 60 months and 3 developing thereafter. Four showed minor recanalization, with only one instance of major recanalization. The latter involved the posterior communicating artery as an apparent de novo lesion, arising at the neck of a firmly coiled sac, and was unrelated to coil compaction or growth. Additional embolization was undertaken. In a multivariate analysis, a second embolization for a recurrent aneurysm (HR = 22.088, p = 0.003) independently correlated with delayed recanalization.

CONCLUSIONS

Almost all coiled aneurysms (98.5%) showing complete occlusion at 36 months postembolization proved to be stable during extended observation. However, recurrent aneurysms were predisposed to delayed recanalization. Given the low probability yet seriousness of delayed recanalization and the possibility of de novo aneurysm formation, careful monitoring may be still considered in this setting but at less frequent intervals beyond 36 months.

Endosaccular Flow Disruption: A New Frontier in Endovascular Aneurysm Management

Flow modification has caused a paradigm shift in the management of intracranial aneurysms. Since the FDA approval of the Pipeline Embolization Device (Medtronic, Dublin, Ireland) in 2011, it has grown to become the modality of choice for a range of carefully selected lesions, previously not amenable to conventional endovascular techniques. While the vast majority of flow-diverting stents operate from within the parent artery (ie, endoluminal stents), providing a scaffold for endothelial cells growth at the aneurysmal neck while inducing intra-aneurysmal thrombosis, a smaller subset of endosaccular flow disruptors act from within the lesions themselves. To date, these devices have been used mostly in Europe, while only utilized on a trial basis in North America. To the best of our knowledge, there has been no dedicated review of these devices. We therefore sought to present a comprehensive review of currently available endosaccular flow disruptors along with high-resolution schematics, presented with up-to-date available literature discussing their technical indications, procedural safety, and reported outcomes.

The Distribution and Role of M1 and M2 Macrophages in Aneurysm Healing after Platinum Coil Embolization

BACKGROUND AND PURPOSE

Impairment of macrophage polarization from a proinflammatory macrophage type 1 (M1) population to an anti-inflammatory macrophage type 2 (M2) population is a hallmark of poor wound healing. In this study, we aimed to evaluate the distribution of M1 and M2 macrophages and to analyze their association with healing in aneurysms embolized by endovascular coiling.

MATERIALS AND METHODS

Elastase-induced aneurysms were created in female rabbits and subsequently embolized with platinum coils. Aneurysm occlusions were evaluated with angiographic imaging at 1 (n = 6), 3 (n = 5), or 6 (n = 6) months. Aneurysm tissues were harvested for histologic analysis, quantification of M1 and M2 macrophages by immunofluorescence, and collagen deposition determined by Masson trichrome staining. Histologic grading of aneurysm healing was also performed. Untreated aneurysms were used as controls (n = 6).

RESULTS

The M1 macrophage population was highest at 1 month posttreatment, progressively decreasing at 3 and 6 months. The M2 macrophage population progressively increased at 3 and 6 months posttreatment. The highest collagen deposition was at 6 months posttreatment. We found a moderate-to-weak direct correlation between the percentage of M2 macrophages and collagen deposition, as well as total histologic scores overall, and a strongly positive direct correlation between the percentage of M2 macrophages and total histologic scores at 6 months posttreatment.

CONCLUSIONS

Our data support the direct correlation between M2 macrophage polarization and healing in aneurysm tissues. Our results show a positive relationship between M2 macrophage populations and total histologic scores at later stages of healing after endovascular coiling. We conclude that interventions aimed at stimulating M2 macrophage expression locally may improve aneurysm healing after coil embolization.

Delayed Progression to Major Recanalization in Coiled Aneurysms with Minor Recanalization at 36-Month Follow-up : Incidence and Related Risk Factors

PURPOSE

The aim was to monitor aneurysms that show imaging evidence of minor recanalization 36 months after coil embolization and to determine the rate and related risk factors of major recanalization during more prolonged observation.

METHODS

A total of 54 patients with 55 aneurysms showing minor recanalization at 36-month follow-up imaging between 2011 and 2013 were retrospectively reviewed. Medical records and radiological data accumulating in the course of extended monitoring (mean 83.9 ± 21.5 months) were assessed. Incidence and average annual risk of progression to major recanalization were then calculated. Univariate and multivariate regression analyses were applied to determine possible risk factors for progression to major recanalization.

RESULTS

In the 55 aneurysms studied 26 showed sustained minor recanalization since month 6 of follow-up, whereas minor recanalization of 29 completely occluded coiled lesions appeared in follow-up images after 6-24 months. Only 8 coiled aneurysms (14.5%) with minor recanalization at 36 months progressed to major recanalization during 219.3 aneurysm-years of observation (3.6% per aneurysm-year), 2 surfacing within 72 months and 6 developing thereafter. Additional embolization was performed in six of these patients. By multivariate analysis, no clinical or anatomic factors were statistically linked to such progression, but younger age showed marginal significance (hazard ratio, HR = 1.076; p = 0.099).

CONCLUSION

Most coiled aneurysms (85.5%) showing minor recanalization at 36 months postembolization proved to be stable in extended observation. Given the low probability but seriousness of delayed major recanalization, careful monitoring is still warranted in this setting but at less frequent intervals (every 2-3 years) beyond 36 months.

Cost-Effectiveness of Computed Tomography Angiography in Management of Tiny Unruptured Intracranial Aneurysms in the United States

Background and Purpose—

Our study aims to evaluate the cost-effectiveness of computed tomography angiography (CTA) for surveillance of tiny unruptured intracranial aneurysms and the impact of CTA radiation-induced brain tumor on the overall effectiveness of CTA.

Methods—

A Markov decision model was constructed from a societal perspective starting with patients 30-, 40-, or 50-year-old, with incidental detection of unruptured intracranial aneurysm ≤3 mm and no prior history of subarachnoid hemorrhage. Five different management strategies were assessed (1) annual CTA surveillance, (2) biennial CTA, (3) CTA follow-up every 5 years, (4) coiling and subsequent magnetic resonance imaging follow-up, and (5) annual CTA surveillance for the first 2 years, followed by every 5-year CTA follow-up. Probabilistic, 1-way, and 2-way sensitivity analyses were performed.

Results—

The base case calculation shows every 5-year CTA follow-up to be the most cost-effective strategy, and the conclusion remains robust in probabilistic sensitivity analysis. It remains the dominant strategy when the annual rupture risk of nongrowing unruptured intracranial aneurysms is smaller than 2.66% or the rupture risk in growing aneurysms is <57.4%. The radiation-induced brain cancer risk is relatively low, and sensitivity analysis shows that the radiation-induced cancer risk does not influence the conclusions unless the risk exceeds 663-fold of the base case values.

Conclusions—

Given the current literature, every 5-year CTA imaging follow-up is the cost-effective strategy in patients with aneurysms ≤3 mm, resulting in better health outcomes and lower healthcare spending. Patients with aneurysms at high risk of rupture might need more aggressive management.

Residuals, recurrences and re-treatment after endovascular repair of intracranial aneurysms: A retrospective methodological comparison

OBJECTIVE

Incomplete aneurysm occlusions and re-treatment rates of 52 and 10-30%, respectively, have been reported following endovascular treatment of intracranial aneurysms, raising clinical concerns regarding procedural efficacy. We compare residual, recurrence and re-treatment rates subject to different endovascular techniques in both ruptured and unruptured intracranial aneurysms at a comprehensive state-wide tertiary neurovascular centre in Australia.

METHODS

Medical records, procedural and follow-up imaging studies of all patients who underwent endovascular treatment for intracranial aneurysms between July 2010 and July 2017 were reviewed retrospectively. Residuals, recurrences and re-treatment rates were assessed regarding initial aneurysm rupture status and applied endovascular technique: primary coiling, balloon- and stent-assisted coiling and flow diversion.

RESULTS

Among 233 aneurysms, residual, recurrence and re-treatment rates were 27, 11.2 and 9.4%, respectively. Compared with unruptured aneurysms, similar residual and recurrence (p > .05), but higher re-treatment rates (4.5% vs. 19%; p < .001) were found for ruptured aneurysms. Residual, recurrence and re-treatment rates were: 13.3, 16 and 12% for primary coiling; 12, 12 and 10.7% for balloon-assisted coiling; 14.9, 7.5 and 4.5% for stent-assisted coiling; 91.9, 0 and 5.4% for flow diversion. Stent-assistance and flow-diversion were associated with lower recurrence and re-treatment rates, when compared with primary- and balloon-assisted coiling (p < .05).

CONCLUSIONS

Residuals and recurrences after endovascular treatment of intracranial aneurysms are less common than previously reported. Stent assistance and flow diversion seem associated with reduced recurrence- and re-treatment rates, when compared with primary- and balloon-assisted coiling. Restrained use of stents in ruptured aneurysms may be a contributing factor for higher recurrence/retreatment rates compared to unruptured aneurysms.

Management of Unruptured Intracranial Aneurysms in Older Adults: A Cost-effectiveness Analysis

Background Unruptured intracranial aneurysms (UIAs) are relatively common and are being increasingly diagnosed, with a significant proportion in older patients (˃ 65 years old). Serial imaging is often performed to assess change in size or morphology of UIAs since growing aneurysms are known to be at high risk for rupture. However, the frequency and duration of surveillance imaging have not been established. Purpose To evaluate the cost-effectiveness of routine treatment (aneurysm coil placement) versus four different strategies for imaging surveillance of UIAs in adults older than 65 years. Materials and Methods A Markov decision-analytic model was constructed from a societal perspective. Age-dependent input parameters were obtained from published literature. Analysis included adults older than 65 years, with incidental detection of UIA and no prior history of subarachnoid hemorrhage. Five different management strategies for UIAs in older adults were evaluated: (a) annual MR angiography, (b) biennial MR angiography, (c) MR angiography every 5 years, (d) coil placement and follow-up, and (e) limited MR angiography follow-up for the first 2 years after detection only. Outcomes were assessed in terms of quality-adjusted life-years (QALYs). Probabilistic, one-way, and two-way sensitivity analyses were performed. Results Imaging follow-up for the first 2 years after detection is the most cost-effective strategy (cost = $24 572, effectiveness = 13.73 QALYs), showing the lowest cost and highest effectiveness. The conclusion remains robust in probabilistic and one-way sensitivity analyses. Time-limited imaging follow-up remains the optimal strategy when the annual growth rate and rupture risk of growing aneurysms are varied. If annual rupture risk of nongrowing aneurysms is greater than 7.1%, coil placement should be performed directly. Conclusion Routine preventive treatment or periodic, indefinite imaging follow-up is not a cost-effective strategy in all adults older than 65 years with unruptured intracranial aneurysms. More aggressive management strategies should be reserved for patients with high risk of rupture, such as those with aneurysms larger than 7 mm and those with aneurysms in the posterior circulation. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Cloft in this issue.

Treatment of broad-based intracranial aneurysms with low profile braided stents: a single center analysis of 101 patients

BACKGROUND AND PURPOSE

Low profile braided stents have facilitated the endovascular treatment of broad-based intracranial aneurysms.

METHODS

Between 2013 and June 2018, we attempted 104 Leo baby stent placements in 101 patients. Locations were the anterior communicating artery (AcomA) (37 aneurysms, 35.6%), middle cerebral artery (MCA) bifurcation (29 aneurysms, 27.9%) and basilar artery (23aneurysms, 22.1%). Mean neck size was 4.9 mm (2.2-8.2). 60 aneurysms were incidental, 31 of 37 recurrent aneurysms had ruptured before.

RESULTS

Stent deployment was successful in 89.4% of cases. Common reasons for failure were inability to access the parent artery (n=5) or to deploy the stent across the aneurysm neck (n=4). Two patients had poor outcomes within 24 hours. One patient developed a brain hemorrhage caused by guide wire perforation (MRS 5), the other an early thrombotic stent occlusion (MRS 4). No patient died. Nine (8.7%) patients experienced transient neurological deficits with ischemic lesions on diffusion weighted imaging (DWI). Initially Raymond-Roy class 1 occlusion was achieved in 23 aneurysms (24.7%), class 2 occlusion in 40 (43%), class 3a occlusion in 14 (15.0%), and 3b occlusion in 16 aneurysms (17.2%). Follow-up imaging in 87 patients showed stable or improved occlusion grades in 76%. Six patients required retreatment while the rest were managed conservatively. Four delayed stent occlusions occurred in three patients, with severe morbidity in one patient (MRS 5). There were no aneurysm ruptures or deaths.

CONCLUSION

Stent assisted treatment of broad-based aneurysms with the Leo baby stent is safe and effective. The frequency of delayed thrombotic complications is low and similar to other stents.

Endovascular Treatment of Wide Neck Aneurysms

BACKGROUND

An aneurysm is an abnormal focal dilatation of an artery. Most of the unruptured aneurysms are asymptomatic and discovered incidentally or some of them symptomatic with mass effect or nerve palsy, but rupture of aneurysm results in a potentially life-threatening subarachnoid haemorrhage. Aneurysms with wide necks are defined by neck diameters greater than 4 mm or dome-to-neck ratios less than 2 and are the most difficult to treat with the endovascular method.

AIM

This study aimed to analyse the endovascular treatment of intracranial aneurysms with a wide neck.

METHODS

The study population included 37 patients with 46 aneurysms referred to the University Clinic of Radiology in Skopje, the Republic of Macedonia for endovascular treatment during the period January 2013 to May 2018. This study included 24 females and 13 males, ranging in age from 25 to 74 years.

RESULTS

From total 46 treated aneurysms 13 were ruptured and 33 unruptured. Six patients were with multiple aneurysms. In these study complex aneurysms were treated with combined technique, 5 with balloon-assisted coiling, 25 with stent-assisted coiling, 6 stents, 2 with flow diverter assisted coiling, 6 FD and 2 with partial coil filling without assistance device.

CONCLUSION

Aneurysms with wide neck remain a challenge for endovascular treatment. But the development of new techniques and materials in the treatment of aneurysms makes endovascular treatment of intracranial aneurysms safe and feasible.

Development of New Endovascular Devices for Aneurysm Treatment

Since the first use of the Guglielmi detachable coil system for cerebral aneurysm embolization in 1990, various endovascular methods have been developed to treat large numbers of aneurysms. The main strategic and technical modifications introduced to date include balloon-assisted coil embolization, stent-assisted coil embolization, flow diverters, and flow disrupters. The development and introduction of such devices have been so persistent and rapid that new devices are being approved worldwide even before the earlier ones become available in some countries. However, even if some patient populations may possibly benefit from earlier introduction of new devices, the approval authorities should balance the available evidence of the safety and effectiveness of novel devices. This review aims to provide an overview of the recent innovations in endovascular treatment of cerebral aneurysms and a brief review of market access policies and regulations for importing high-risk medical devices, such as those used for endovascular aneurysm management, which correspond to class III devices, as defined by the U.S. Food and Drug Administration. We focus on the current situation in Korea and compare it with that in other Asian countries, such as China and Japan.

Voxel based analysis of recurrence dynamics in intracranial aneurysms after coiling

BACKGROUND

Understanding aneurysm growth is critical for the appropriate follow-up of patients after coil embolization and the need for retreatment. The purpose of the study was to stratify the growth dynamics of aneurysm recurrences after coiling by volumetric analysis and to determine predictive factors for aneurysm recurrences.

METHODS

Source images of follow-up three-dimensional time of flight MR angiography (ToF-MRA) scans were compared with the first post-interventional ToF-MRA scan and analyzed for residual flow after co-registration using ANALYZE-software. In the event of incomplete occlusion, the residual volume was segmented and calculated. Growth dynamic was determined for each aneurysm after embolization.

RESULTS

We analyzed 326 patients with 345 aneurysms from two centers. Each case had at least two ToF-MRA examinations after endovascular therapy. The mean observation interval was 59 months. Volumetric analysis of 1139 follow-up MRAs revealed that 218/345 aneurysms (63.2%) showed complete occlusion on initial follow-up imaging, and of these 95.0% remained stable. A steady increase in intra-aneurysmal flow was observed in 83/345 (24.1%). Less frequent observations were a steep increase (21/345; 6.1%) and a decrease (27/345; 7.8%). Independent predictors of increasing residual flow were greatest aneurysm diameter, total coil length, and incomplete occlusion.

CONCLUSIONS

Volumetric analysis of registered three-dimensional ToF-MRA follow-up datasets allows the detection of different growth patterns with high precision, avoids the low inter-rater reliability, and represents a promising approach for future studies that include analysis of more complex predictors of residual flow. In cases of aneurysm recurrence after coiling, the major pattern seems to be a steady increase in intra-aneurysmal flow over several months.

Treatment of recurrent aneurysms using the Woven EndoBridge (WEB): anatomical and clinical results

Background

The safety and efficacy of the Woven EndoBridge (WEB) for the treatment of naïve intracranial aneurysms has been confirmed.

Purpose

To analyze the safety and efficacy of the WEB in the treatment of recurrent aneurysms.

Methods

Anatomical and clinical results in consecutive patients with a recurrent aneurysm, who were treated using the WEB device in two French neurointerventional centers, were evaluated.

Results

Seventeen patients with 17 aneurysms were included. Treatment was feasible in 16 patients. In seven patients (41.2%), ancillary devices were used. Permanent morbidity due to a thromboembolic complication occurred in one patient (5.9%). There was no mortality. Follow-up angiographic studies were available for 15 patients after a mean of 12.1±6.1 months. Rates of complete occlusion, neck remnant, and aneurysm remnant were 33.3%, 40.0%, and 26.7%, respectively.

Conclusions

Treatment of recurrent aneurysms using the WEB device may be reasonably safe and effective.

Optimisation of a novel glass-alginate hydrogel for the treatment of intracranial aneurysms

The current gold standard for aneurysm treatment is endovascular coiling. However, recurrence is observed in over 20% of cases. A novel hydrogel has been developed to treat aneurysms. This hydrogel is composed of a polymeric alginate, a novel ion releasing glass and glucono-delta-lactone. This is an internally setting alginate hydrogel, wherein the setting rate can be controlled by both the glass and the alginate chemistry. The aim of this work is to examine the effect of each component of the hydrogel and optimise the composition of the hydrogel, specifically the alginate molecular weight, M/G ratio and concentration. The effects of gamma sterilisation will also be examined. The results show that alginate concentration, chemical composition and molecular weight affect the compressive strength, working time, hardening time and deliverability of the hydrogel. Gamma irradiation of the alginate reduces the molecular weight, which has a negative effect on the usability of this hydrogel.

Virtual endovascular treatment of intracranial aneurysms: models and uncertainty

Virtual endovascular treatment models (VETMs) have been developed with the view to aid interventional neuroradiologists and neurosurgeons to pre-operatively analyze the comparative efficacy and safety of endovascular treatments for intracranial aneurysms. Based on the current state of VETMs in aneurysm rupture risk stratification and in patient-specific prediction of treatment outcomes, we argue there is a need to go beyond personalized biomechanical flow modeling assuming deterministic parameters and error-free measurements. The mechanobiological effects associated with blood clot formation are important factors in therapeutic decision making and models of post-treatment intra-aneurysmal biology and biochemistry should be linked to the purely hemodynamic models to improve the predictive power of current VETMs. The influence of model and parameter uncertainties associated to each component of a VETM is, where feasible, quantified via a random-effects meta-analysis of the literature. This allows estimating the pooled effect size of these uncertainties on aneurysmal wall shear stress. From such meta-analyses, two main sources of uncertainty emerge where research efforts have so far been limited: (1) vascular wall distensibility, and (2) intra/intersubject systemic flow variations. In the future, we suggest that current deterministic computational simulations need to be extended with strategies for uncertainty mitigation, uncertainty exploration, and sensitivity reduction techniques. WIREs Syst Biol Med 2017, 9:e1385. doi: 10.1002/wsbm.1385 For further resources related to this article, please visit the WIREs website.

Anterior Communicating Artery Aneurysm Treatment with the Pipeline Embolization Device: A Single-Center Experience with Long-Term Follow-Up

Introduction

The pipeline embolization device (PED) is increasingly used in the endovascular management of cerebral aneurysms. Longitudinal data regarding safety and benefit of the PED in anterior communicating (ACOM) artery aneurysms are limited and particularly lacking in residual ACOM artery aneurysms. We report the use of the PED in 3 patients with ACOM artery aneurysms who were previously coiled.

Methods

Three patients with ACOM artery aneurysms, all previously treated with coiling and with recurrence of the aneurysm neck, were treated with the PED. All obtained follow-up diagnostic cerebral angiograms at either 3 or 6 months.

Results

Mean age of patients was 59 years. All patients received cerebral angiograms at a minimum of 3 months after treatment with the PED. Follow-up angiography was performed up to a mean of 10 months at which time point all cases demonstrated complete aneurysm occlusion, without any stenosis in the parent artery.

Conclusion

The PED can be safely used for the treatment of ACOM artery aneurysms. Complete aneurysm obliteration can be achieved in cases refractory to endovascular coiling. These findings warrant replication in a larger data set.

Hydrogel versus Bare Platinum Coils in Patients with Large or Recurrent Aneurysms Prone to Recurrence after Endovascular Treatment: A Randomized Controlled Trial

BACKGROUND AND PURPOSE

Some patients are at high risk of aneurysm recurrence after endovascular treatment: patients with large aneurysms (Patients Prone to Recurrence After Endovascular Treatment PRET-1) or with aneurysms that have previously recurred after coiling (PRET-2). We aimed to establish whether the use of hydrogel coils improved efficacy outcomes compared with bare platinum coils.

MATERIALS AND METHODS

PRET was an investigator-led, pragmatic, multicenter, parallel, randomized (1:1) trial. Randomized allocation was performed separately for patients in PRET-1 and PRET-2, by using a Web-based platform ensuring concealed allocation. The primary outcome was a composite of a residual/recurrent aneurysm, adjudicated by a blinded core laboratory, or retreatment, intracranial bleeding, or mass effect during the 18-month follow-up. Secondary outcomes included adverse events, mortality, and morbidity (mRS > 2). The hypothesis was that hydrogel would decrease the primary outcome from 50% to 30% at 18 months, necessitating 125 patients per group (500 for PRET-1 and PRET-2).

RESULTS

The trial was stopped once 250 patients in PRET-1 and 197 in PRET-2 had been recruited because of slow accrual. A poor primary outcome occurred in 44.4% (95% CI, 35.5%-53.2%) of those in PRET-1 allocated to platinum compared with 52.5% (95% CI, 43.4%-61.6%) of patients allocated to hydrogel (OR, 1.387; 95% CI, 0.838-2.295; P = .20) and in 49.0% (95% CI, 38.8%-59.1%) in PRET-2 allocated to platinum compared with 42.1% (95% CI, 32.0%-52.2%) allocated to hydrogel (OR, 0.959; 95% CI, 0.428-1.342; P = .34). Adverse events and morbidity were similar. There were 3.6% deaths (1.4% platinum, 5.9% hydrogel; P = .011).

CONCLUSIONS

Coiling of large and recurrent aneurysms is safe but often poorly effective according to angiographic results. Hydrogel coiling was not shown to be better than platinum.

Bipolar radiofrequency ablation of aneurysm remnants after coil embolization can improve endovascular treatment of experimental bifurcation aneurysms

OBJECTIVE Endovascular treatment of aneurysms may result in incomplete initial occlusion and aneurysm recurrence at angiographic follow-up studies. This study aimed to assess the feasibility and efficacy of bipolar radiofrequency ablation (RFA) of aneurysm remnants after coil embolization. METHODS Bipolar RFA was accomplished using the coil mass as 1 electrode, while the second electrode was a stent placed across the aneurysmal neck. After preliminary experiments and protocol approval from the Animal Care committee, wide-necked bifurcation aneurysms were constructed in 24 animals. Aneurysms were allocated to 1 of 3 groups: partial intraoperative coil embolization, followed by RFA (n = 12; treated group) or without RFA (n = 6; control group 1); or attempted complete endovascular coil embolization 2-4 weeks later (n = 6; control group 2). Angiographic results were compared at baseline, immediately after RFA, and at 12 weeks, using an ordinal scale. Pathological results and neointima formation at the neck were compared using a semiquantitative grading scale. RESULTS Bipolar RFA was able to reliably target the aneurysm neck when the coil mass and stent were used as electrodes. RFA improved angiographic results immediately after partial coiling (p = 0.0024). Two RFA-related complications occurred, involving transient occlusion of 1 carotid artery and 1 hemorrhage from an adventitial arterial blister. At 12 weeks, angiographic results were improved with RFA (median score of 0), when compared with controls (median score of 2; p = 0.0013). Neointimal closure of the aneurysm neck was better with RFA compared with controls (p = 0.0003). CONCLUSIONS Bipolar RFA can improve results of embolization in experimental models by selectively ablating residual lesions after coil embolization.

Inter- and Intrarater Agreement on the Outcome of Endovascular Treatment of Aneurysms Using MRA

BACKGROUND AND PURPOSE

Patients treated with coiling are often followed by MR angiography. Our objective was to assess the inter- and intraobserver agreement in diagnosing aneurysm remnants and recurrences by using multimodality imaging, including TOF MRA.

MATERIALS AND METHODS

A portfolio composed of 120 selected images from 56 patients was sent to 15 neuroradiologists from 10 institutions. For each case, raters were asked to classify angiographic results (3 classes) of 2 studies (32 MRA-MRA and 24 DSA-MRA pairs) and to provide a final judgment regarding the presence of a recurrence (no, minor, major). Six raters were asked to independently review the portfolio twice. A second study, restricted to 4 raters having full access to all images, was designed to validate the results of the electronic survey.

RESULTS

The proportion of cases judged to have a major recurrence varied between 16.1% and 71.4% (mean, 35.0% ± 12.7%). There was moderate agreement overall (κ = 0.474 ± 0.009), increasing to nearly substantial (κ = 0.581 ± 0.014) when the judgment was dichotomized (presence or absence of a major recurrence). Agreement on cases followed-up by MRA-MRA was similarly substantial (κ = 0.601 ± 0.018). The intrarater agreement varied between fair (κ = 0.257 ± 0.093) and substantial (κ= 0.699 ± 0.084), improving with a dichotomized judgment concerning MRA-MRA comparisons. Agreement was no better when raters had access to all images.

CONCLUSIONS

There is an important variability in the assessment of angiographic outcomes of endovascular treatments. Agreement on the presence of a major recurrence when comparing 2 MRA studies or the MRA with the last catheter angiographic study can be substantial.

Controlled release of osteopontin and interleukin-10 from modified endovascular coil promote cerebral aneurysm healing

Cerebral aneurysm is a bulging of the artery inside the brain that results from a weakened or thin area of the artery wall. Ruptured cerebral aneurysm could lead to serious brain damage or even death, thus the proper treatment is essential. Compared with the conventional microsurgical clipping approach, the endovascular coiling treatment has many advantages, however, with a major disadvantage of high recurrence rate. One way to lower the recurrence rate, which has been tried since one decade ago, is to modify the coil to be bioactive and releasing biological molecules to stimulate tissue ingrowth and aneurysm healing. We have identified three candidates including osteopontin (OPN), IL-10 and matrix metallopeptidase 9 (MMP-9) from previous studies and generated platinum coils coated with these proteins in the carrier of poly-DL-lactic glycolic acid (PLGA). We were interested to know whether coils coated with OPN, IL-10 and MMP-9 were able to promote aneurysm healing and we have tested it in the rat carotid aneurysm model. We found that OPN and IL-10 coated coils had shown significant improvement in tissue ingrowth while MMP-9 coated coils failed to enhance tissue ingrowth compared with the control group. Our studies suggested the possible application of OPN and IL-10 coated coils in aneurysm treatment to overcome the recurrence.

Stent-Assisted Coiling of Wide-Neck Intracranial Aneurysms Using Low-Profile LEO Baby Stents: Initial and Midterm Results

BACKGROUND AND PURPOSE

Low-profile self-expandable stents were recently introduced for the treatment of wide-neck intracranial aneurysms. This study investigated the initial and midterm clinical and angiographic results of LEO Baby stent-assisted coiling in the treatment of wide-neck intracranial aneurysms.

MATERIALS AND METHODS

A retrospective review was performed to identify patients who were treated with LEO Baby stent-assisted coiling. Eighty patients with 80 wide-neck intracranial aneurysms were included in the study. Eleven patients (13.8%) presented with subarachnoid hemorrhage. All patients were treated with LEO Baby stent-assisted coiling. Technical success and immediate postprocedural clinical and angiographic outcomes were evaluated. Seventy-three patients attended angiographic and clinical follow-up for a mean duration of 7.2 ± 3.8 months. Periprocedural and delayed complications were reviewed. Preprocedural and follow-up clinical statuses were assessed by using the modified Rankin Scale.

RESULTS

The technical success rate of the procedure was 97.5%. The immediate postprocedural angiography revealed a complete occlusion of the aneurysm in 75% of the 80 patients. The last follow-up angiograms showed complete occlusion in 85.7% of the 77 patients with an angiographic follow-up. Of the 77 patients with a follow-up angiography, 6.5% showed an increase in the filling status of the aneurysm and 5.2% required retreatment. The overall procedure-related complication rate, including asymptomatic complications, was 11.3%. The permanent morbidity rate was 3.8%. There was no mortality in this study.

CONCLUSIONS

This case series demonstrates the relative safety, efficacy, and midterm durability of the LEO Baby stent-assisted coiling procedure for the treatment of wide-neck intracranial aneurysms.

A New Aneurysm Occlusion Classification after the Impact of Flow Modification

A new classification is proposed for cerebral aneurysms treated with any endovascular technique, for example, coiling with or without adjunctive devices, flow diversion, intrasaccular flow modifiers, or any combination of the above. Raymond-Roy Occlusion Classification is expanded with novel subgroups such as class 1 represents complete occlusion and is subdivided if a branch is integrated to, or originated from, the aneurysm sac; class 2 represents neck filling; class 3 represents incomplete occlusion with aneurysm filling as in the previous classification; and class 4 describes the immediate postoperative status after extra- or intrasaccular flow modification treatment. A new concept, "stable remodeling," is included as class 5, which represents filling in the neck region that stays unchanged or reduced, as shown with at least 2 consecutive control angiographies, at least 6 months apart, for not <1 year, or the remodeled appearance of a dilated and/or tortuous vessel in continuation with the parent artery without sac filling.

Mechanisms of Healing in Coiled Intracranial Aneurysms: A Review of the Literature

Recanalization of intracranial aneurysms following endovascular coiling remains a frustratingly common occurrence. An understanding of the molecular and histopathologic mechanisms of aneurysm healing following coil embolization is essential to improving aneurysm occlusion rates. Histopathologic studies in coiled human and experimental aneurysms suggest that during the first month postcoiling, thrombus formation and active inflammation occur within the aneurysm dome. Several months following embolization, the aneurysm is excluded from the parent vessel by formation of a neointimal layer, which is often thin and discontinuous, across the aneurysm neck. Numerous coil modifications and systemic therapies have been tested in animals and humans in an attempt to improve the aneurysm-healing process; these modifications have met with variable levels of success. In this review, we summarize the histopathologic and molecular biology of aneurysm healing and discuss how these findings have been applied in an attempt to improve angiographic outcomes in patients with intracranial aneurysms.

HydroCoils reduce recurrence rates in recently ruptured medium-sized intracranial aneurysms: a subgroup analysis of the HELPS trial

BACKGROUND AND PURPOSE

The HydroCoil Endovascular Aneurysm Occlusion and Packing Study (HELPS) was a randomized, controlled trial comparing HydroCoils with bare-platinum coils. The purpose of this study was to perform a subgroup analysis of angiographic and clinical outcomes of medium-sized aneurysms in the HELPS trial.

MATERIALS AND METHODS

Patients with medium-sized aneurysms (5-9.9 mm) were selected from the HELPS trial. Outcomes compared between the HydroCoil and bare-platinum groups included the following: 1) any recurrence, 2) major recurrence, 3) retreatment, and 4) mRS score of ≤2. Subgroup analysis by rupture status was performed. Multivariate logistic regression analysis adjusting for aneurysm neck size, shape, use of adjunctive device, and rupture status was performed.

RESULTS

Two hundred eighty-eight patients with medium-sized aneurysms were randomized (144 in each group). At 15-18 months posttreatment, the major recurrence rate was significantly lower in the HydroCoil group than in controls (18.6% versus 30.8%, P = .03, respectively). For patients with recently ruptured aneurysms, the major recurrence rate was significantly lower for the HydroCoil group than for controls (20.3% versus 47.5%, P = .003), while rates were similar between groups for unruptured aneurysms (16.7% versus 14.8%, P = .80). Multivariate analysis of patients with recently ruptured aneurysms demonstrated a lower odds of major recurrence with HydroCoils (OR = 0.27; 95% CI, 0.12-0.58; P = .0007). No difference in retreatment rates or mRS of ≤2 was seen between groups.

CONCLUSIONS

HydroCoils were associated with statistically significant and clinically relevant lower rates of major recurrence for recently ruptured, medium-sized aneurysms in the HELPS trial. Because this was not a prespecified subgroup analysis, these results should not alter clinical practice but, rather, provide insight into the design of future clinical trials comparing bare platinum with second-generation coils.

Long-term catheter angiography after aneurysm coil therapy: results of 209 patients and predictors of delayed recurrence and retreatment

OBJECT

Aneurysm recurrence after coil therapy remains a major shortcoming in the endovascular management of cerebral aneurysms. The need for long-term imaging follow-up was recently investigated. This study assessed the diagnostic yield of long-term digital subtraction angiography (DSA) follow-up and determined predictors of delayed aneurysm recurrence and retreatment.

METHODS

Inclusion criteria were as follows: 1) available short-term and long-term (> 36 months) follow-up DSA images, and 2) no or only minor aneurysm recurrence (not requiring further intervention, i.e., < 20%) documented on short-term follow-up DSA images.

RESULTS

Of 209 patients included in the study, 88 (42%) presented with subarachnoid hemorrhage. On shortterm follow-up DSA images, 158 (75%) aneurysms showed no recurrence, and 51 (25%) showed minor recurrence (< 20%, not retreated). On long-term follow-up DSA images, 124 (59%) aneurysms showed no recurrence, and 85 (41%) aneurysms showed recurrence, of which 55 (26%) required retreatment. In multivariate analysis, the predictors of recurrence on long-term follow-up DSA images were as follows: 1) larger aneurysm size (p = 0.001), 2) male sex (p = 0.006), 3) conventional coil therapy (p = 0.05), 4) aneurysm location (p = 0.01), and 5) a minor recurrence on short-term follow-up DSA images (p = 0.007). Ruptured aneurysm status was not a predictive factor. The sensitivity of short-term follow-up DSA studies was only 40.0% for detecting delayed aneurysm recurrence and 45.5% for detecting delayed recurrence requiring further treatment.

CONCLUSIONS

The results of this study highlight the importance of long-term angiographic follow-up after coil therapy for ruptured and unruptured intracranial aneurysms. Predictors of delayed recurrence and retreatment include large aneurysms, recurrence on short-term follow-up DSA images (even minor), male sex, and conventional coil therapy.

Analysis of recanalization after endovascular treatment of intracranial aneurysm (ARETA trial): presentation of a prospective multicenter study

PURPOSE

Aneurysm recanalization is a main concern after endovascular treatment of intracranial aneurysms. But to date, no systematic analysis of the risk factors affecting its occurrence has been conducted in a large series of patients. Analysis of Recanalization after Endovascular Treatment of intracranial Aneurysm (ARETA) is a multicenter, prospective trial whose aim is to collect a large series of patients treated endovascularly to analyze factors affecting aneurysm recanalization.

STUDY DESIGN

Patients with ruptured or unruptured aneurysms treated endovascularly will be enrolled from December 2013 to December 2014 in 19 participating centers in France. Patient and aneurysm characteristics will be recorded as well as the type of endovascular treatment and the occurrence of procedural or post-procedural complications. Post-procedural and follow-up imaging after one year will be analyzed independently by two readers using a 3-grade scale (complete occlusion, neck remnant, or aneurysm remnant). The progression of aneurysm occlusion will also be evaluated (improved, stable, or worsened). Aneurysm occlusion at one year and progression of aneurysm occlusion will be analyzed in light of patient, aneurysm, and treatment factors.

CONCLUSION

ARETA is a large, prospective, multicenter trial designed to assess predictive factors of aneurysm recanalization after endovascular treatment of intracranial aneurysms.

Identification of the inflow zone of unruptured cerebral aneurysms: comparison of 4D flow MRI and 3D TOF MRA data

BACKGROUND AND PURPOSE

The hemodynamics of the inflow zone of cerebral aneurysms may be a key factor in coil compaction and recanalization after endovascular coil embolization. We performed 4D flow MR imaging in conjunction with 3D TOF MRA and compared their ability to identify the inflow zone of unruptured cerebral aneurysms.

MATERIALS AND METHODS

This series comprised 50 unruptured saccular cerebral aneurysms in 44 patients. Transluminal color-coded 3D MRA images were created by selecting the signal-intensity ranges on 3D TOF MRA images that corresponded with both the luminal margin and the putative inflow.

RESULTS

4D flow MR imaging demonstrated the inflow zone and yielded inflow velocity profiles for all 50 aneurysms. In 18 of 24 lateral-projection aneurysms (75%), the inflow zone was located distally on the aneurysmal neck. The maximum inflow velocity ranged from 285 to 922 mm/s. On 4D flow MR imaging and transluminal color-coded 3D MRA studies, the inflow zone of 32 aneurysms (64%) was at a similar location. In 91% of aneurysms whose neck section plane angle was <30° with respect to the imaging section direction on 3D TOF MRA, depiction of the inflow zone was similar on transluminal color-coded 3D MRA and 4D flow MR images.

CONCLUSIONS

4D flow MR imaging can demonstrate the inflow zone and provide inflow velocity profiles. In aneurysms whose angle of the neck-section plane is obtuse vis-a-vis the imaging section on 3D TOF MRA scans, transluminal color-coded 3D MRA may depict the inflow zone reliably.

Flow diversion versus traditional aneurysm embolization strategies: analysis of fluoroscopy and procedure times

BACKGROUND AND OBJECTIVE

Flow diverters are increasingly used for treatment of complex intracranial aneurysms. The purpose of this study was to compare the pipeline embolization device (PED) and traditional embolization strategies in terms of fluoroscopy and procedure time.

MATERIAL AND METHODS

Fluoroscopy and procedure times (in minutes) were retrospectively analyzed and compared between 127 patients treated with the PED, 86 patients treated with single stage stent assisted coiling (SAC), and 16 patients treated with Onyx HD 500 at our institution. A multivariate logistic regression analysis was performed to determine independent predictors of fluoroscopy and procedure time.

RESULTS

The three groups were comparable with respect to patient age, gender, and ruptured/unruptured aneurysm status. Aneurysms treated with the PED were significantly larger than stent coiled aneurysms, and aneurysm location distribution differed significantly between the three groups. Mean fluoroscopy time was significantly increased in the SAC (55±31 min, p<0.001) and Onyx HD 500 (91±36 min, p<0.001) groups relative to the PED group (34±23 min). Likewise, mean procedure time was significantly longer in SAC (155±50 min, p<0.001) and Onyx HD 500 (176±65 min, p<0.001) patients compared with PED patients (131±36 min). In multivariate analysis, SAC/Onyx HD 500 versus PED independently predicted longer procedure and fluoroscopy times.

CONCLUSIONS

PED treatment requires significantly shorter fluoroscopy and procedure times compared with SAC and Onyx HD 500. The results of this study may be used by advocates of flow diverters as an additional argument for using this treatment modality to treat intracranial aneurysms.

Efficacy and safety of flow diversion for paraclinoid aneurysms: a matched-pair analysis compared with standard endovascular approaches

BACKGROUND AND PURPOSE

Flow diversion is a new strategy for the treatment of complex paraclinoid aneurysms. However, flow diverters have, to date, not been tested in direct comparison with other available treatments. We present a matched-pair comparison of paraclinoid aneurysms treated with the PED versus other endovascular techniques.

MATERIALS AND METHODS

Twenty-one eligible patients with 22 paraclinoid aneurysms treated with the PED at our institution were matched with historic controls with aneurysms of similar size and location.

RESULTS

There were no statistically significant differences between the 2 groups in terms of aneurysm size, location, risk factors, or comorbidities. Mean dome size was 13.9 ± 6.7 mm in the control group and 14.9 ± 6.3 mm in the PED group (P = .52). Balloon and stent assistance were used in 31.8% and 9.1% of controls, respectively, while carotid sacrifice was used in 36.4% of the controls. There was a significant difference in the rate of complete occlusion favoring PED at radiologic follow-up (P = .03).

CONCLUSIONS

Flow diverters achieve a much higher rate of complete angiographic obliteration compared with other standard endovascular techniques in the treatment of internal carotid artery aneurysms. In this series, this higher angiographic obliteration rate did not occur at the expense of an increased rate of complications. Careful long-term follow-up is of the utmost importance to definitively validate flow diversion as a superior therapeutic strategy for proximal internal carotid artery aneurysms.