Natural history of the neck remnant of a cerebral aneurysm treated with the Guglielmi detachable coil system

Large, Wide-Neck, Side-Wall Aneurysm Treatment in Canines Using NeuroCURE: A Novel Liquid Embolic

BACKGROUND

Untreated intracranial aneurysms can rupture and result in high rates of morbidity and mortality. Although there are numerous approved endovascular aneurysm treatment devices, most require dual anti-platelet therapy, are minimally biocompatible, or are prone to recanalization. Neurovascular Controlled Uniform Rapid Embolic (NeuroCURE) is an innovative polymer gel material with long-term stability, biocompatibility, and hemocompatibility developed for the treatment of large, wide-neck aneurysms.

METHODS

Sidewall aneurysms were surgically created in 10 canines and NeuroCURE was injected through a 0.025 microcatheter under a single balloon inflation period. Aneurysm treatment was angiographically assessed post-embolization and pre-term with Raymond-Roy occlusion classification and a qualitative flow grade scale. Aneurysm neck stability and biocompatibility was histologically assessed to grade platelet/fibrin thrombus, percent endothelialization, and neointimal formation. Aneurysm sac stability was assessed by NeuroCURE sac content, inflammation, and neo-angiogenesis scales.

RESULTS

Explanted aneurysms exhibited a smooth surface at the aneurysm neck with nearly complete neointimal coverage at 3-months. By 6-months, neck endothelialization was 100% in all animals (average Raymond-Roy occlusion classification of 1.2), with no instances of aneurysm recanalization or parent vessel flow compromise. Biocompatibility assessments verified a lack of inflammatory response, neo-angiogenesis, and platelet/fibrin thrombus formation.

CONCLUSION

The NeuroCURE material promotes progressive occlusion of wide-necked side wall aneurysms over time without the need for dual antiplatelet agents. NeuroCURE also promotes neointimal tissue infill without dependence on thrombus formation and thus resists aneurysm recanalization. NeuroCURE remains a compelling investigational device for the treatment of intracranial aneurysms.

Aspect Ratio Is Associated with Recanalization after Coiling of Unruptured Intracranial Aneurysms

The rate of recanalization after coil embolization for unruptured intracranial aneurysms (UIAs) is reported to occur around 11.3%-49%. This study aims to investigate the factors that influence the recanalization after coil embolization for UIAs in our institution. We retrospectively investigated 307 UIAs in 296 patients treated at our institution between April 2004 and December 2016. The stent-used cases were excluded. Cerebral angiography and 3D time-of-flight magnetic resonance angiography (TOF MRA) were used for evaluation of the postoperative occlusion status. Volume embolization ratio (VER), aneurysmal size, neck width, and aspect ratio (AR) were compared between the recanalized and non-recanalized groups. The mean follow-up period ranged from 6 to 172 months (mean: 79.0 ± 39.8 months). Recanalization was noted in 78 (25.4%) aneurysms, and 19 (6.2%) aneurysms required retreatment. There was no aneurysmal rupture during the follow-up period. Univariate analysis showed that the aneurysm size (p < 0.001), neck width (p < 0.001), AR (p = 0.003), and VER (p = 0.012) were associated with recanalization. Multivariate logistic regression analysis showed that the AR (p =0.004) and VER (p =0.015) were significant predictors of recanalization. To summarize, a higher AR and a lower VER could lead to recanalization after coil embolization of UIAs. Careful follow-up is required for coiled aneurysms with these features.

In situ crosslinking temperature-responsive hydrogels with improved delivery, swelling, and elasticity for endovascular embolization

Endovascular embolization of cerebral aneurysms is a common approach for reducing the risk of often-fatal hemorrhage. However, currently available materials used to occlude these aneurysms provide incomplete filling (coils) or require a complicated, time-consuming delivery procedure (solvent-exchange precipitating polymers). The objective of this work was to develop an easily deliverable in situ forming hydrogel that can occlude the entire volume of an aneurysm. The hydrogel is formed by mixing a solution of a temperature-responsive polymer containing pendent thiol groups (poly(NIPAAm-co-cysteamine) or poly(NIPAAm-co-cysteamine-co-JAAm)) with a solution of poly(ethylene glycol) diacrylate (PEGDA). Incorporation of hydrophilic grafts of polyetheramine acrylamide (JAAm) in the temperature-responsive polymer caused weaker physical crosslinking, facilitated faster and more complete chemical crosslinking, and increased gel swelling. One formulation (30 wt % PNCJ20 + PEGDA) could be delivered for over 220 s after mixing, formed a strong and elastic hydrogel (G' > 6000 Pa) within 30 min and once set, maintained its shape and volume in a model aneurysm under flow. This gel represents a promising candidate water-based material utilizing both physical and chemical crosslinking that warrants further investigation as an embolic agent for saccular aneurysms.

Treatment of Ruptured and Nonruptured Aneurysms Using a Semisolid Iodinated Embolic Agent

Saccular aneurysms (SAs) are focal outpouchings from the lateral wall of an artery. Depending on their morphology and location, minimally invasive treatment options include coil embolization, flow diverter stents, stent-assisted coiling, and liquid embolics. Many drawbacks are associated with these treatment options including recanalization, delayed healing, rebleeding, malpositioning of the embolic or stent, stent stenosis, and even rupture of the SA. To overcome these drawbacks, a nanoclay-based shear-thinning hydrogel (STH) is developed for the endovascular treatment of SAs. Extensive in vitro testing is performed to optimize STH performance, visualization, injectability, and endothelialization in cell culture. Femoral artery saccular aneurysm models in rats and in pigs are created to test stability, efficacy, immune response, endothelialization, and biocompatibility of STH in both ruptured and unruptured SA. Fluoroscopy and computed tomography imaging consistently confirmed SA occlusion without recanalization, migration, or nontarget embolization; STH is also shown to outperform coil embolization of porcine aneurysms. In pigs with catastrophic bleeding due to SA rupture, STH is able to achieve instant hemostasis rescuing the pigs in long-term survival experiments. STH is a promising semisolid iodinated embolic agent that can change the standard of medical practice and potentially save lives.

Risk Factors for Recanalization after Coil Embolization

The aim of our study was to identify risk factors for recanalization 6 months after coil embolization using clinical data followed by computational fluid dynamics (CFD) analysis. Methods: Firstly, clinical data of 184 patients treated with coil embolization were analyzed retrospectively. Secondly, aneurysm models for high/low recanalization risk were generated based on ROC curves and their cut-off points. Afterward, CFD was utilized to validate the results. Results: In multivariable analysis, aneurysm filling during the first embolization was an independent risk factor whilst packing density was a protective factor of recanalization after 6 months in patients with aSAH. For patients with unruptured aneurysms, packing density was found to be a protective factor whilst the aneurysm neck size was an independent risk factor. Complex flow pattern and multiple vortices were associated with aneurysm shape and were characteristic of the high recanalization risk group. Conclusions: Statistical analysis suggested that there are various factors influencing recanalization risk. Once certain values of morphometric parameters are exceeded, a complex flow with numerous vortices occurs. This phenomenon was revealed due to CFD investigations that validated our statistical research. Thus, the complex flow pattern itself can be treated as a relevant recanalization predictor.

Intracranial aneurysms in pediatric population: a two-center audit

OBJECTIVE

Intracranial aneurysms (IA) in children are rare, accounting for less than 5% of all IA. Due to their scarcity, the epidemiology is poorly understood and differs from adults in term of clinical presentation, size, location, and origin. Consequently, the treatment strategies are specific and cannot be only based on data from adult series. The aim of our study was to report the characteristics, management, and outcomes of children treated for IA in two university hospitals located in Normandy (France) over the last 17 years and to perform a literature review of this rare pathology.

METHODS

This retrospective study included 18 consecutive children (< 18 years old) admitted with cerebral aneurysm treated in two neurosurgery departments in Normandy, from 2001 to 2018. Computerized tomography and cerebral angiography established the diagnosis. Both endovascular and surgical procedures were discussed in all cases. Data focused on clinical condition at admission, characteristics of the IA, choice of the treatment modalities, and complications. The outcome at follow-up is based on Glasgow outcomes scale (GOS) at 1 year.

RESULTS

During the study period, 18 children (mean age: 12.6 years; sex ratio male/female: 2.3) were admitted with 21 IA. Aneurysms had a mean size of 13.6 mm with 4 giant aneurysms and were mostly located in the anterior circulation (16/21). Clinical presentations at onset were sudden symptoms related to a subarachnoid hemorrhage in 13 patients, headaches in 4 patients with giant aneurysm, and asymptomatic in one patient. Among the 13 patients with ruptured IA, 6 presented in poor preoperative condition (Hunt and Hess Grade ≥ 4). Treatment modalities consisted in embolization in 9 patients and surgery in 9 patients including 2 by-pass surgeries in fusiform aneurysms. Complications were similar in the two groups, but two cases of recanalization were observed in the endovascular group. At 1 year of follow-up, 14 children were in good condition (GOS Score > 4) and one died. Three children presented associated IA treated by the same technique as initial aneurysm.

CONCLUSIONS

Pediatric aneurysm is a different pathology compared with adults, occurring more frequently in male population with a higher proportion of giant aneurysms and aneurysms located in the internal carotid bifurcation. The use of endovascular techniques has progressed in the last years, but surgery was proposed for half of our population.

Application of a rabbit-elastase aneurysm model for preliminary histology assessment of the PPODA-QT liquid embolic

Background

PPODA-QT is a novel liquid embolic under development for the treatment of cerebral aneurysms. We sought to test the rabbit-elastase aneurysm model to evaluate the tissue response following PPODA-QT embolization.

Methods

Experimental elastase-induced aneurysms were created in fourteen New Zealand White Rabbits. Eight animals were used for aneurysm model and endovascular embolization technique development. Six PPODA-QT-treated animals were enrolled in the study. Control and aneurysm tissues were harvested at acute (n = 2), 1-month (n = 2), and 3-month (n = 2) timepoints and the tissues were prepared for histology assessment.

Results

All fourteen rabbit-elastase aneurysms resulted in small and medium aneurysm heights (<10 mm dome height) with highly variable neck morphologies, small midline dome diameters, and beyond-wide dome-to-neck (d: n) ratios. Histological evaluation of four aneurysms, treated with PPODA-QT, demonstrated reorganization of aneurysm wall elastin into a smooth muscle layer, and observed as early as the 1-month survival timepoint. At the aneurysm neck, a homogenous neointimal layer (200-300 μm) formed at the PPODA-QT interface, sealing off the parent vessel from the aneurysm dome. No adverse immune response was evident at 1- and 3-month survival timepoints.

Conclusion

PPODA-QT successfully embolized the treated aneurysms. Following PPODA-QT embolization, neointimal tissue growth and remodeling were noted with minimal immunological response. The experimental aneurysms created in rabbits were uniformly small with inconsistent neck morphology. Further testing of PPODA-QT will be conducted in larger aneurysm models for device delivery optimization and aneurysm healing assessment before human clinical investigation.

Comparison between outcomes of endovascular and surgical treatments of ruptured anterior communicating artery aneurysms

INTRODUCTION

The natural history and optimal treatment of previously ruptured anterior communicating artery (ACOM) aneurysms that recur is unknown. This study looks at rates of complications and recurrences of ruptured ACOM aneurysms treated endovascularly and surgically.

MATERIALS AND METHODS

A retrospective observational study of all patients presenting to a single tertiary neurosurgical centre with the first presentation of subarachnoid haemorrhage (SAH) secondary to a ruptured ACOM aneurysm. Data was collected from November 2012 to September 2018 and included baseline demographics, aneurysm characteristics, management, complications, follow-up imaging, and clinical outcomes.

RESULTS

137 patients were included in the study. 113 aneurysms were coiled and 19 were clipped. Management decisions were taken by the multidisciplinary team based on aneurysm morphology or the presence of a haematoma exerting mass effect. There were 187.5 patient-years of follow-up, with a median of 3 years (range 0-73 months). Rates of vasospasm, infarction, CSF diversion, rebleed, length of stay, and functional outcome were not significantly different in the two cohorts. There was a statistically significant increase in the risk of ACOM recurrence in the coiled group when compared to the clipped group at one year (p = .0433). 15 patients required further treatment at a median time of 16 months. In a subgroup group analysis of coiled aneurysms, there was no statistical differences in rates of rebleeding or the functional outcome in those that had aneurysm recurrence and those that did not.

CONCLUSIONS

This study suggests patients with aneurysms treated by endovascular coiling have an increased risk of recurrence versus those treated with clipping. However, the risk of rebleed was not statistically significant. The prevention and impact of recurrence and residual aneurysms remains incompletely understood. Hence, treatment decisions should be taken by patients after they have been given carefully considered recommendations from the multi-disciplinary team.

Intra-aneurysmal pressure changes during stent-assisted coiling

We aimed to examine aneurysm hemodynamics with intra-saccular pressure measurement, and compare the effects of coiling, stenting and stent-assisted coiling in proximal segments of intracranial circulation. A cohort of 45 patients underwent elective endovascular coil embolization (with or without stent) for intracranial aneurysm at our department. Arterial pressure transducer was used for all measurements. It was attached to proximal end of the microcatheter. Measurements were taken in the parent artery before and after embolization, at the aneurysm dome before embolization, after stent implantation, and after embolization. Stent-assisted coiling was performed with 4 different stents: LVIS and LVIS Jr (Microvention, Tustin, CA, USA), Leo (Balt, Montmorency, France), Barrel VRD (Medtronic/ Covidien, Irvine, CA, USA). Presence of the stent showed significant reverse correlation with intra-aneurysmal pressure–both systolic and diastolic—after its implantation (r = -0.70 and r = -0.75, respectively), which was further supported by correlations with stent cell size–r = 0.72 and r = 0.71, respectively (P<0.05). Stent implantation resulted in significant decrease in diastolic intra-aneurysmal pressure (p = 0.046). Systolic or mean intra-aneurysmal pressure did not differ significantly. Embolization did not significantly change the intra-aneurysmal pressure in matched pairs, regardless of the use of stent (p>0.05). In conclusion, low-profile braided stents show a potential to divert blood flow, there was significant decrease in diastolic pressure after stent placement. Flow-diverting properties were related to stent porosity. Coiling does not significantly change the intra-aneurysmal pressure, regardless of packing density.

'Railroad switch' technique for stent-assisted coil embolization of a wide-neck bifurcation intracranial aneurysm: technical note

Preservation of the posterior cerebral arteries during endovascular treatment of wide-neck basilar bifurcation aneurysms remains a technical challenge despite recent device innovations. We present a novel stent deployment technique, the 'railroad switch', to protect both posterior cerebral arteries during treatment of a recurrent basilar bifurcation aneurysm. Following asymmetric basilar-posterior cerebral artery stent deployment, favoring distal placement in a posterior cerebral artery, advancement of a jailed microcatheter will advance the proximal stent into the aneurysm, protecting both posterior cerebral arteries and the native basilar terminus. This novel maneuver offers interventionalists another application of commonly used intracranial stents for endovascular management of complex basilar bifurcation aneurysms.

Neck Remnants and the Risk of Aneurysm Rupture After Endovascular Treatment With Coiling or Stent-Assisted Coiling: Much Ado About Nothing?

BACKGROUND

Neck remnants are not uncommon after endovascular treatment of cerebral aneurysms. Critics of endovascular treatments for cerebral aneurysms cite neck remnants as evidence in favor of microsurgical clipping. However, studies have failed to evaluate the true clinical significance of aneurysm neck remnants following endovascular therapies.

OBJECTIVE

To assess the clinical significance of residual aneurysm necks and to determine the rate of subsequent rupture following coiling or stent-assisted coiling of cerebral aneurysms.

METHODS

We retrospectively reviewed the records of 1292 aneurysm cases that underwent endovascular treatment at 4 institutions. Aneurysms treated by primary coiling or stent-assisted coiling were included in the study; those treated by flow diversion were excluded Aneurysms with residual filling (i.e., Raymond-Roy Occlusion Classification II, neck remnant; or III, residual aneurysm filling) were assessed for their risk of subsequent rupture.

RESULTS

A total of 626 aneurysms were identified as having residual filling immediately posttreatment. Of these, 13 aneurysms (2.1%) ruptured during the follow-up period (mean 7.3 mo; range 1-84 mo). Eleven of the 13 (84.6%) were ruptured at presentation. Rupture at presentation, the size of the aneurysm, and the increasing age of the patient were predictive of posttreatment rupture.

CONCLUSION

We found that unruptured aneurysms with residual necks following endovascular treatment posed a very low risk of rupture (0.6%). However, patients presenting with ruptured aneurysms had a higher risk of rerupture from a neck remnant (3.4%). These results highlight the importance of achieving complete angiographic occlusion of ruptured aneurysms.

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 recurrent intracranial aneurysms after coil embolization: a novel classification scheme based on angiography

OBJECTIVERecurrent aneurysms after coil embolization remain a challenging issue. The goal of the present study was to report the authors' experience with recurrent aneurysms after coil embolization and to discuss the radiographic classification scheme and recommended management strategy.METHODSAneurysm treatments from a single institution over a 6-year period were retrospectively reviewed. Ninety-seven aneurysms that recurred after initial coiling were managed during the study period. Recurrent aneurysms were classified into the following 5 types based on their angiographic characteristics: I, pure recanalization inside the aneurysm sac; II, pure coil compaction without aneurysm growth; III, new aneurysm neck formed without coil compaction; IV, new aneurysm neck formed with coil compaction; and V, newly formed aneurysm neck and sac.RESULTSAneurysm recurrences resulted in rehemorrhages in 6 cases (6.2%) of type III-V aneurysms, but in none of type I-II aneurysms. There was a significantly higher proportion of ophthalmic artery aneurysms and complex internal carotid artery aneurysms presenting as types I and II than presented as the other 3 types (63.3% vs 16.4%, p < 0.001). In contrast, for posterior communicating artery aneurysms and anterior communicating artery aneurysms, a higher proportion of type III-V aneurysms was observed than for the other 2 types, but without a significant difference in the multivariate model (56.7% vs 23.3%). In addition, giant (> 25 mm) aneurysms were more common among type I and II lesions than among type III and IV aneurysms (36.7% vs 9.0%, p = 0.001), which exhibited a higher proportion of small (< 10 mm) lesions (65.7% vs 13.3%, p < 0.001). A single reembolization procedure was sufficient to occlude 80.0% of type I recurrences and 83.3% of type II recurrences from coil compaction but only 65.6% of type III-V recurrences from aneurysm regrowth.CONCLUSIONSAneurysm size and location represent the determining factors of the angiographic recurrence types. Type I and II recurrences were safely treated by reembolization, whereas type III-V recurrences may be best managed surgically when technically feasible.

Recurrence of Small Cerebral Aneurysms (< 4 mm) Treated Endovascularly Using Target® Nano™ Coils

OBJECTIVE

In our series, endovascular coiling with Target® Nano™ coils (Stryker Neurovascular, Fremont, CA, USA) with diameters of 1 or 1.5 mm exhibited favorable technical feasibility in the treatment of small cerebral aneurysms (< 4 mm). However, little is known about the recurrence of small cerebral aneurysms treated using Target® Nano™ coils. We investigated recurrence following the treatment of small cerebral aneurysms using Target® Nano™ coils.

MATERIALS AND METHODS

Between January 2012 and November 2013, 143 patients with 148 small cerebral aneurysms (< 4 mm) were included our study. A total of 135 cerebral aneurysms (91.2%) were unruptured; 45 cerebral aneurysms (30.4%) were treated by endovascular coiling using Target® Nano™ coils. Follow-up radiological images were obtained for 132 cerebral aneurysms (89.2%) over a range of 3 to 58 months (mean, 34.3 months; standard deviation, 14.2).

RESULTS

In the group treated with Target® Nano™ coils, radiological outcomes revealed complete occlusion in 33 (73.3%), residual necks in eight (17.8%), and residual sacs in four (8.9%) cases. Follow-up radiological outcomes revealed complete occlusion in 35 (77.8%) and residual necks in four (8.9%) cases that exhibited stable coil masses. In the group that was not treated with Target® Nano™ coils, radiological outcomes revealed complete occlusion in 69 (67%), residual necks in 18 (17.5%), and residual sacs in 16 (15.5%) cases. Follow-up radiological outcomes revealed complete occlusion in 87 (84.5%) and residual necks (5.8%) in six cases that exhibited stable coil masses. No significant differences were observed in the radiological outcomes or follow-up radiological outcomes between the two groups. No recurrences or retreatments occurred in our series.

CONCLUSION

Endovascular treatment using Target® Nano™ coils may be a robust treatment option for small cerebral aneurysms (< 4 mm).

The Effect of Stents in Cerebral Aneurysms: A Review

The etiology of up to 95% of cerebral aneurysms may be accounted for by hemodynamically-induced factors that create vascular injury. The purpose of this review is to describe key physical properties that stents have and how they affect cerebral aneurysms. We performed a two-step screening process. First, a structured search was performed using the PubMed database. The following search terms and keywords were used: “Hemodynamics,” “wall shear stress (WSS),” “velocity,” “viscosity,” “cerebral aneurysm,” “intracranial aneurysm,” “stent,” “flow diverter,” “stent porosity,” “stent geometry,” “stent configuration,” and “stent design.” Reports were considered if they included original data, discussed hemodynamic changes after stent-based treatment of cerebral aneurysms, examined the hemodynamic effects of stent deployment, and/or described the geometric characteristics of both stents and the aneurysms they were used to treat. The search strategy yielded a total of 122 articles, 61 were excluded after screening the titles and abstracts. Additional articles were then identified by cross-checking reference lists. The final collection of 97 articles demonstrates that the geometric characteristics and configurations of deployed stents influenced hemodynamic parameters such as aneurysmal WSS, inflow, and pressure. The geometric characteristics of the aneurysm and its position also had significant influences on intra-aneurysmal hemodynamics after treatment. In conclusion, changes in specific aneurysmal hemodynamic parameters that result from stenting relate to a number of factors including the geometric properties and configurations of deployed stents, the geometric properties of the aneurysm, and the pretreatment hemodynamics.

Korean Clinical Practice Guidelines for Aneurysmal Subarachnoid Hemorrhage

Despite advancements in treating ruptured cerebral aneurysms, an aneurysmal subarachnoid hemorrhage (aSAH) is still a grave cerebrovascular disease associated with a high rate of morbidity and mortality. Based on the literature published to date, worldwide academic and governmental committees have developed clinical practice guidelines (CPGs) to propose standards for disease management in order to achieve the best treatment outcomes for aSAHs. In 2013, the Korean Society of Cerebrovascular Surgeons issued a Korean version of the CPGs for aSAHs. The group researched all articles and major foreign CPGs published in English until December 2015 using several search engines. Based on these articles, levels of evidence and grades of recommendations were determined by our society as well as by other related Quality Control Committees from neurointervention, neurology and rehabilitation medicine. The Korean version of the CPGs for aSAHs includes risk factors, diagnosis, initial management, medical and surgical management to prevent rebleeding, management of delayed cerebral ischemia and vasospasm, treatment of hydrocephalus, treatment of medical complications and early rehabilitation. The CPGs are not the absolute standard but are the present reference as the evidence is still incomplete, each environment of clinical practice is different, and there is a high probability of variation in the current recommendations. The CPGs will be useful in the fields of clinical practice and research.

Autologous adipose-derived mesenchymal stem cells improve healing of coiled experimental saccular aneurysms: an angiographic and histopathological study

PURPOSE

Long-term occlusion of coiled aneurysms frequently fails, probably because of poor intrasaccular healing and inadequate endothelialization across the aneurysm neck. The purpose of this study was to determine if attachment of autologous mesenchymal stem cells (MSCs) to platinum coils would improve the healing response in an elastase-induced aneurysm model in rabbits.

MATERIALS AND METHODS

With approval from the institutional animal care and use committee, aneurysms were created in rabbits and embolized with control platinum coils (Axium; Medtronic) (n=6) or coils seeded ex vivo with autologous adipose-tissue MSCs (n=7). Aneurysmal occlusion after embolization was evaluated at 1 month with angiography. Histological samples were analyzed by gross imaging and graded on the basis of neck and dome healing on H&E staining. Fibrosis was evaluated using a ratio of the total area presenting collagen. Endothelialization of the neck was quantitatively analyzed using CD31 immunohistochemistry. χ² and Student's t-test were used to compare groups.

RESULTS

Healing score (11.5 vs 8.0, p=0.019), fibrosis ratio (10.3 vs 0.13, p=0.006) and endothelialization (902 262 μm² vs 31 810 μm², p=0.041) were significantly greater in the MSC group. The MSC group showed marked cellular proliferation and thrombus organization, with a continuous membrane bridging the neck of the aneurysm. Angiographic stable or progressive occlusion rate was significantly lower in the MSC group (0.00, 95% CI 0.00 to 0.41) compared with controls (0.67, 95% CI 0.22 to 0.96) (p=0.02).

CONCLUSIONS

Autologous MSCs attached to platinum coils significantly improve histological healing, as they result in improved neck endothelialization and collagen matrix formation within the aneurysm sac.

Surgical management of recurrent aneurysms after coiling treatment

OBJECTIVE

Aneurysms that recur after coiling treatment are difficult to manage. The microsurgical technique in these cases differs significantly from that in regular aneurysm clipping. We present our experience in surgical management of aneurysms that recurred more than 1 month after coiling in a series of 19 patients.

MATERIALS AND METHODS

Between January 2004 and December 2014, 1437 patients were treated surgically for intracranial aneurysms in our institution. We performed a retrospective review of the clinical records, operation videos, and cerebral angiograms. We focused on patients in whom the initial aneurysm was treated by coiling, but the results were incomplete or the aneurysm recurred.

RESULTS

Nineteen patients underwent surgical clipping for recurrent aneurysm more than 1 month after initial coiling treatment. The sex ratio (male:female) was 0.9, and the average age was 51.3 years (range 35-72 years). One aneurysm was classified as giant (≥ 25 mm), two as large (10-25 mm), and 18 as small (≤ 10 mm). A good outcome (Glasgow Outcome Scale 4 or 5) was observed in 16 of 19 patients (84.2%).

CONCLUSION

Microsurgical clipping can be safe and effective in the management of previously coiled residual and recurrent aneurysms.

Endovascular Treatment of Intracranial Aneurysms: Long-Term Follow-up

Endovascular treatment of intracranial aneurysms is increasingly used and has evolved as an alternative to surgical clipping. However, its long-term efficacy has yet to be established. This retrospective hospital based (tertiary teaching hospital) study aimed to identify factors that might be important in predicting initial efficacy of this treatment and a long-term follow-up to study the clinical and angiographic results of treated aneurysms. A total of 80 aneurysms in 78 patients were treated and analyzed, and the percentage of occlusion calculated. Overall, 51/80 (64 %) cases were treated with selective endovascular coil occlusion and 29/80 (36 %) by parent artery occlusion. The shape of the aneurysm rest was noted on the immediate post treatment and follow-up angiograms. Immediate and follow-up clinical status was also noted using the Glasgow outcome scale. The clinical and radiological changes on follow-up were assessed and possible factors involved were analyzed. Of the 50 patients of intracranial aneurysms that underwent selective aneurysm coiling, good immediate outcome (Glasgow outcome scale 1 and 2) was seen in 36/50 (72 %) cases. Narrow necked aneurysms showed a good immediate result (90–100 % packing) in all cases 28/28 (100 %). Amongst the wide necked aneurysms, good packing (90–100 %) was achieved in 17/23 (73 %) cases. Amongst the cases treated with parent artery occlusion, complete occlusion was noted in 20/29 (69 %) cases. No subarachnoid hemorrhage was seen in any of the followed up cases of coiled aneurysms. A statistically significant relationship was noted between aneurysm neck size and immediate angiographic outcome. Long-term angiographic recurrences were found more often in large aneurysms. Endovascular treatment of intracranial aneurysms is a safe and effective treatment modality that offers protection from recurrent subarachnoid hemorrhage.

Angiographic and Clinical Results after Endovascular Treatment for Middle Cerebral Artery Berry Aneurysms

Sixty-five middle cerebral artery (MCA) aneurysms in 59 patients treated by endovascular treatment (EVT) without the remodelling technique were analyzed. For ruptured aneurysms, the patients in bad condition are predominant and those with Fisher group four is 47.8% and with Hunt and Hess grade (HHG) IV or V are 43.5%. The clinical result is that 58.7% is in mRS 0–3, 21.7% in 4–5 and 19.6% in death. Contrary, 92.3% of the patients in HHG I-III resulted in mRS 0–3. Re-rupture was observed in two cases (4.4%). For all the aneurysms, thromboembolic complications were observed in 12.3% and those were predominant in the aneurysms greater than 10mm in diameter (p<0.05). Hemorrhagic ones occurred in 6.2% which were predominant in the aneurysms less than 10mm in diameter. No mortality was observed by the accidents. In follow-up angiography, Raymond classification was employed and Complete Obliteration or Dog Ear was observed in 24 of 43 cases (55.8%). Recanalization occurred in 10.5% of the cases with complete or almost complete obliterated aneurysms. These results suggested that EVT for the ruptured MCA aneurysms with good grade or the unruptured ones is feasible. Strict follow-up is important like the other aneurysms.

Analysis of Multiple Intracranial Aneurysms with Different Outcomes in the Same Patient After Endovascular Treatment

BACKGROUND

Aneurysm recanalization after coiling, with or without stent assistance, is a major issue in the endovascular management of intracranial aneurysms. Multiple intracranial aneurysms with different outcomes after endovascular treatment may represent a useful disease model in which patient-specific risk factors can be balanced to investigate possible features linked to aneurysm recanalization. In the present study, we evaluated the impact of aneurysm-specific, treatment-related, and hemodynamics-related factors on multiple aneurysms and to explore the reason why one aneurysm recanalized and the other did not.

METHODS

Between 2010 and 2015, 763 multiple intracranial aneurysms in 326 patients were diagnosed by digital subtraction angiography. We retrospectively collected and analyzed 13 pairs of multiple aneurysms with different outcomes (recanalized or stable) in the same patient. Patient-specific models were constructed and analyzed by a computational fluid dynamics method. The virtual stent deployment method was used, and the coils were simulated by a porous medium model. Factors were evaluated for significance with respect to recanalization.

RESULTS

Aneurysm size (P = 0.021), neck width (P = 0.027), ruptured aneurysms (P = 0.002), reduction ratio of averaged velocity (P = 0.008), and wall shear stress (P = 0.024) were significantly associated with aneurysm recanalization. By contrast, the aneurysm location, all of treatment-related factors (packing density, duration of follow-up, stent use, initial angiographic result) and the reduction ratio of averaged pressure were not significantly associated (P > 0.05).

CONCLUSIONS

Small aneurysm size and neck width, unruptured aneurysm, and perianeurysmal hemodynamics with marked reduction may be important factors associated with the midterm durability of aneurysm embolization.

[Endovascular treatment of large and giant intracranial aneurysms using stent assistance]

OBJECTIVE

The study objective was to evaluate the efficacy of occlusions of large and giant intracranial aneurysms with microcoils using stent assistance (SA).

MATERIAL AND METHODS

The study is based on analysis of treatment outcomes in 37 patients with large (15-25mm) and giant (more than 25mm) intracranial aneurysms, aged 18 to 72 years, who were hospitalized at the Burdenko Neurosurgical Institute in the period between 2004 and 2014. Selection of patients for endovascular treatment using SA was based on the anatomical parameters of the aneurysm and carrier vessel. The main determining factor was the index of the aneurysm body to neck size ratio. Occlusion of aneurysms was performed with microcoils of different configurations, including those with a biologically active coating. Self-expanding stents with both an open-cell and closed-cell design were used for SA. The results of intervention for large and giant aneurysms were evaluated using control angiography immediately after occlusion of the aneurysm. The condition of patients with unruptured aneurysms as well as with ruptured aneurysms in the "cold" period was evaluated using the modified Rankin scale. The condition of patients in the acute period of SAH was evaluated on the Hunt and Hess scale.

RESULTS

The technical success (successful implantation of stents and coils with total or subtotal aneurysm occlusion) was 94.5%. The postoperative disability was 2.7%; mortality was 2.7%. 28 patients were followed up for the period of 5 to 84 months (the mean was 20 months.). In the long-term period, the total and subtotal occlusion rate, including the results of re-operations, amounted to 90%. Delayed disability was 10.7%, and mortality was 3.5%.

CONCLUSION

Stent assistance enables achieving total or subtotal occlusion of large and giant aneurysms in 90% of cases. In certain clinical situations, it is an alternative to other existing methods.

[De novo cerebral aneurysms]

OBJECTIVE

To substantiate the reasonability and duration of angiographic follow-up of patients operated on for cerebral aneurysms to rule out de novo aneurysm formation.

MATERIAL AND METHODS

The results of angiographic examination (cerebral angiography and SCT angiography) of 43 patients with cerebral aneurysms operated on at the Burdenko Neurosurgical Institute in 1995-2012 are analyzed. The follow-up duration varied from 1 to 14 years after surgery (mean duration, 5 years). Patients' age ranged from 14 to 56 years.

RESULTS

Control angiographic examination showed that de novo aneurysms were formed in 7 (16.2%) patients. A total of 8 de novo aneurysms were detected (in one case there were two aneurysms formed). All aneurysms, both the previously operated and the de novo ones, were located in the anterior part of the circle of Willis. De novo aneurysms were clipped in 5 cases; the cavity of the de novo aneurysm was occluded with spirals in one case. One patient with a small aneurysm of the middle cerebral artery refused surgery. Neither lethal nor unfavorable outcomes were recorded.

CONCLUSIONS

The patient groups with the high risk of de novo aneurysm formation are as follows: 1) young smokers with hypertension; 2) patients who developed clinical signs of the disease when being young; 3) patients subjected to proximal exclusion of the main artery; and 4) patients with multiple and familial forms of the pathology. Dynamic angiographic follow-up (SCT angiography or magnetic resonance angiography) for 1-3 years is recommended for these patients.

Temporo-sylvian anastomosis and aneurysm clipping in a case of left M1 aneurysm with progressive evolution after initial embolization; Case report

A giant unrupted middle cerebral artery aneurysm partially thrombosed, previously endovascularly treated after a mild right hemiparesis remitted. After 12 months, in routine check we discovered a reperfusion of the aneurysm and decide ECIC bypass and clipping, with a good outcome

Angiographic results of wide-necked intracranial aneurysms treated with coil embolization : a single center experience

Objective

Endovascular treatment of wide-necked intracranial aneurysms is a challenge and the durability and the safety of these treated aneurysms remain unknown. The aim of this study was to evaluate the clinical and long-term angiographic results of wide-necked intracranial aneurysms treated with coil embolization.

Methods

Between January 2002 and December 2012, 53 wide-necked aneurysms treated with coil embolization were selected. Forty were female, and 13 were male. Twenty eight (52.8%) were ruptured aneurysms, and 25 (47.2%) were unruptured aneurysms. The patents' medical and radiological records were reviewed retrospectively.

Results

Of the 53 aneurysms, coiling alone was employed in 45 (84.9%) and stent-assisted coiling was done in 8 (15.1%). The initial angiographic results revealed Raymond class 1 (complete occlusion) in 30 (56.6%) cases, Raymond class 2 (residual neck) in 18 (34.0%) cases, and Raymond class 3 (residual sac) in 5 (9.4%) cases. The mean angiographic follow-up period was 37.9 months (12-120 months). At the last angiographies, Raymond class 1 was seen in 26 (49.1%) cases, Raymond class 2 in 16 (30.2%), and Raymond class 3 in 11 (20.8%). Angiographic recurrence occurred in 22 (41.5%) patients, with minor recurrence in 7 (13.2%) cases and major recurrence in 15 (28.3%). Retreatment was performed in 8 cases (15.1%). A suboptimal result on the initial angiography was a significant predictor of recurrence in this study (p=0.03).

Conclusion

The predictor of recurrence in wide-necked aneurysms is a suboptimal result on the initial angiography. Long-term angiographic follow-up is recommended in wide-necked aneurysms.

Microsurgical Treatment of Previously Coiled Intracranial Aneurysms: Systematic Review of the Literature

OBJECTIVE

To assess indications, complications, clinical outcomes, and technical nuances of microsurgical treatment of previously coiled intracranial aneurysms.

METHODS

A systematic review of the literature was performed using PubMed/MEDLINE and EMBASE databases from January 1990 to December 2013. English-language articles reporting on microsurgical treatment of previously coiled intracranial aneurysms were included. Articles that involved embolization materials other than coils were excluded. Data on aneurysm characteristics, indications for surgery, techniques, complications, angiographic obliteration rates, and clinical outcomes were collected.

RESULTS

The literature review identified 29 articles reporting on microsurgical clipping of 375 previously coiled aneurysms. Of the aneurysms, 68% were small (<10 mm). Indications for clipping included the presence of a neck remnant (48%) and new aneurysmal growth (45%). Rebleeding before clipping was reported in 6% of cases. Coil extraction was performed in 13% of cases. The median time from initial coiling to clipping was 7 months. The angiographic cure rate was 93%, with morbidity and mortality of 9.8% and 3.6%, respectively.

CONCLUSIONS

Microsurgical clipping of previously coiled aneurysms can result in high obliteration rates with relatively low morbidity and mortality in select cases. Considerations for microsurgical strategies include the presence of sufficient aneurysmal tissue for clip placement and the potential need for temporary occlusion or flow arrest. Coil extraction is not needed in most cases.

Endovascular embolization is applicable for large and giant intracranial aneurysms: experience in one center with long-term angiographic follow-up

BACKGROUND

Endovascular treatment of large and giant intracranial aneurysms and long-term results of angiographic follow-up of these aneurysms treated endovascularly are not known currently.

PURPOSE

To investigate the outcome of endovascular treatment of large and giant aneurysms and the long-term angiographic follow-up results.

MATERIAL AND METHODS

A retrospective analysis of all patients with endovascular treatment of large and giant aneurysms between 1998 and 2009 was performed. There were 90 large or giant aneurysms treated with coiling alone, stent-assisted coiling, covered-stent deployment, or parent artery occlusion (PAO) in 88 patients (female/male, 54/34; age range, 23-92 years; mean age, 56 years).

RESULTS

Immediately after the initial endovascular embolization procedure, complete occlusion was achieved in 56.7%, near complete occlusion in 37.8%, and incomplete occlusion in 5.5%. The total periprocedural complication rate excluding subarachnoid hemorrhage (SAH)-induced vasospasm was 10.2% with a mortality rate of 2.3%. Follow-up angiography was performed in all of the aneurysms with the longest follow-up duration of 131 months. Among 38 aneurysms initially treated with coiling alone and 17 initially treated with stent-assisted coiling, 22 (57.9%) and four (23.5%) recurred, respectively, during follow-up. No recurrence occurred in aneurysms initially treated with covered-stent deployment or PAO. Aneurysm recurrence was predominantly seen in older and female patients, in larger aneurysms, and in aneurysms treated with coiling alone. Twenty-three aneurysms were successfully retreated endovascularly.

CONCLUSION

Endovascular intervention with coiling alone or stent-assisted coiling for large and giant cerebral aneurysms is not very effective, while covered stents are more promising. Better endovascular devices are needed to obtain more secure closure.

Effects of Isophorone Diisocyanate on the Thermal and Mechanical Properties of Shape-Memory Polyurethane Foams

Previously developed shape-memory polymer foams display fast actuation in water due to plasticization of the polymer network. The actuation presents itself as a depression in the glass-transition temperature when moving from dry to aqueous conditions; this effect limits the working time of the foam to 10 min when used in a transcatheter embolic device. Reproducible foams are developed by altering the chemical backbone, which can achieve working times of greater than 20 min. This is accomplished by incorporating isophorone diisocyanate into the foam, resulting in increased hydrophobicity, glass transitions, and actuation time. This delayed actuation, when compared with previous systems, allows for more optimal working time in clinical applications.

Management strategy of surgical and endovascular treatment of unruptured paraclinoid aneurysms based on the location of aneurysms

OBJECTIVE

Advances in endovascular treatment (EVT) have greatly improved the treatment outcomes of paraclinoid aneurysms. However, EVT had the shortcoming of durability and thromboembolic complications. As well, surgical treatment of paraclinoid aneurysms is still challenging due to the complexity of adjacent structures. The objective of this study is to report our experience with a combined surgical and endovascular treatment of unruptured paraclinoid aneurysms based on the location of aneurysms.

METHODS

A retrospective review was conducted of 185 cases of unruptured paraclinoid aneurysms that underwent surgical or endovascular treatment between September 2008 and August 2012. Thirty-one aneurysms (16.8%) were treated by microsurgery and 154 (83.2%) were treated by EVT. Fifty aneurysms (27.0%) were classified to the dorsal group and 135 (73%) were classified to the non-dorsal group.

RESULTS

Twenty of 50 dorsal group aneurysms (40%) were treated by microsurgery while 124 of 135 non-dorsal group aneurysms (91.9%) underwent an EVT. The rate of complete occlusion was 96.8% in surgical series and 60.4% in EVT (P < 0.001). Recanalization occurred in 9 aneurysms (5.8%) of EVT and 1 aneurysm (3.2%) of surgical series (P = 0.360). In non-dorsal group, transient complications (10 aneurysms (5.4%), P = 0.018) and morbidity at last visiting (6 aneurysms (3.2%), P = 0.021) were more present in surgically treated cases rather than in EVT cases. Diplopia and visual field defect occurred in the non-dorsal group only; in 2 of 11 surgical cases (18.2%) and in 1 of 124 EVT series (0.8%) (P = 0.017). The overall rate of excellent or good clinical outcomes (Glasgow outcome scale 5 or 4) was 98.9%.

CONCLUSION

EVT is a safe and effective treatment for the non-dorsal group. Based on angiographic and clinical aspects, microsurgical clipping has prior efficacy with better outcomes in the dorsal group under proper individualized selection.

Single-center experience with a dual microcatheter technique for the endovascular treatment of wide-necked aneurysms

Object

The endovascular treatment of wide-necked aneurysms can be technically challenging due to distal coil migration or impingement of the parent vessel. In this paper, the authors illustrate an alternative method for the treatment of wide-necked intracranial aneurysms using a dual microcatheter technique.

Methods

The authors' first 100 consecutive patients who underwent coil embolization of a wide-necked aneurysm using a dual microcatheter technique are reported. With this technique, 2 microcatheters are used to introduce coils into the aneurysm. The coils are deployed either sequentially or concurrently to form a stable construct and prevent coil herniation or migration. Angiographic and clinical outcomes are reported.

Results

The technical success rate of the dual microcatheter technique is 91% with a morbidity and mortality of 1% and 2%, respectively. Clinical outcomes are excellent with 93% of patients demonstrating a modified Rankin Scale score of 0–2 at long-term follow-up regardless of their score at presentation. Retreatment rates are 18%.

Conclusions

The dual microcatheter technique may be a safe and efficacious first line of treatment for widenecked aneurysms.

Parent artery curvature influences inflow zone location of unruptured sidewall internal carotid artery aneurysms

BACKGROUND AND PURPOSE

Future aneurysmal behaviors or treatment outcomes of cerebral aneurysms may be related to the hemodynamics around the inflow zone. Here we investigated the influence of parent artery curvature on the inflow zone location of unruptured sidewall internal carotid artery aneurysms.

MATERIALS AND METHODS

In 32 aneurysms, the inflow zone location was decided by 4D flow MR imaging, and the radius of the parent artery curvature was measured in 2D on an en face image of the section plane corresponding to the aneurysm orifice.

RESULTS

The inflow zone was on the distal neck in 10 (group 1, 31.3%), on the lateral side in 19 (group 2, 59.4%), and on the proximal neck in 3 (group 3, 9.4%) aneurysms. The radius in group 1 was significantly larger than that in group 2 (8.3 mm [4.5 mm] versus 4.5 mm [1.9 mm]; median [interquartile range]; P < .0001). All 7 aneurysms with a radius of >8.0 mm were in group 1. All 18 aneurysms with a radius of <6.0 mm were in group 2 or 3. In two group 3 aneurysms, the inflow zone was located in a part of the neck extending beyond the central axis of the parent artery.

CONCLUSIONS

The inflow zone locations of sidewall aneurysms can be influenced by the parent artery curvature evaluated in 2D on an en face image of the section plane corresponding to the aneurysm orifice.

Balloons in endovascular neurosurgery: history and current applications

The use of balloons in the field of neurosurgery is currently an essential part of our clinical practice. The field has evolved over the last 40 years since Serbinenko used balloons to test the feasibility of occluding cervical vessels for intracranial pathologies. Since that time, indications have expanded to include sacrificing cervical and intracranial vessels with detachable balloons, supporting the coil mass in wide-necked aneurysms (balloon remodeling technique), and performing intracranial and cervical angioplasty for atherosclerotic disease, as well as an adjunct to treat arteriovenous malformations. With the rapid expansion of endovascular technologies, it appears that the indications and uses for balloons will continue to expand. In this article, we review the history of balloons, the initial applications, the types of balloons available, and the current applications available for endovascular neurosurgeons.

Endovascular coil embolization of aneurysm neck for the treatment of ruptured intracranial aneurysm with bleb formation

Background

Ruptured intracranial aneurysm (ICA) with bleb formation (RICABF) is a special type of ruptured ICA. However, the exact role and effectiveness of endovascular coil embolization (ECE) in RICABF is unknown.

We aimed to investigate the effectiveness and safety of ECE of aneurysm neck for RICABF treatment.

Material/Methods

We retrospectively assessed consecutive patients who were hospitalized in our endovascular intervention center between October 2004 and May 2012. Overall, 86 patients underwent ECE of aneurysm neck for 86 RICABF. Treatments outcomes included secondary rupture/bleeding rate, aneurysm neck embolization rate, residual/recurrent aneurysm, intraoperative incidents, and post-embolization complications, as well as improvements in the Glasgow outcome scale (extended) (GOS-E).

Results

Complete occlusion was achieved in 72 aneurysms (72/86, 83.7%), while 12 aneurysms (12/86, 14.0%) had a residual neck, and 2 aneurysms (2/86, 2.3%) had a residual aneurysm. The postoperative GOS-E was 3 in 3 patients (3.5%), 4 in 10 patients (11.6%), and 5 in 73 patients (84.9%). Follow-up angiography was performed in all patients (mean 9.0 months, interquartile range of 9.0). Recurrence was found in 3 patients (3/86, 3.5%). No aneurysm rupture or bleeding was reported.

Conclusions

Our mid-term follow-up study showed that ECE of aneurysm neck was an effective and safe treatment modality for RICABF. The long-term effectiveness and safety of this interventional radiology technique need to be investigated in prospective and comparative studies.

Flow diversion versus traditional endovascular coiling therapy: design of the prospective LARGE aneurysm randomized trial

BACKGROUND AND PURPOSE

The goal of aneurysm treatment is occlusion of an aneurysm without morbidity or mortality. Using well-established, traditional endovascular techniques, this is generally achievable with a high level of safety and efficacy. These techniques involve either constructive treatment of the aneurysm (coils with or without an intravascular stent) or deconstruction (coil occlusion) of the aneurysm and the parent artery. While established as safe and efficacious, the constructive treatment of large and giant aneurysms with coils has typically been associated with relatively lower rates of complete occlusion and higher rates of recurrence. Parent artery deconstruction, though immediately efficacious in achieving complete and durable occlusion, does require occlusion of a major intracranial blood vessel and is associated with risk of stroke.

MATERIALS AND METHODS

Flow diversion represents a new technology that can be used to constructively treat large and giant aneurysms. Once excluded successfully, the vessel reconstruction and aneurysm occlusion appears durable. The ability to definitively reconstruct cerebral blood vessels is an attractive approach to these large and giant complex aneurysms and allows the treatment of some aneurysms which were previously not amenable to other therapies. By comparison, conventional coiling techniques have traditionally been used for endovascular treatment of large aneurysms. Large and giant aneurysms that are amenable to either flow diversion or traditional endovascular treatment will be randomized to either therapy with FDA (or appropriate regulatory body) approved devices.

RESULTS

The trial is currently enrolling and results of the data are pending the completion of enrollment and follow-up.

CONCLUSIONS

This paper details the trial design of the LARGE trial, a blinded, prospective randomized trial of large anterior circulation aneurysms amenable to either traditional endovascular treatments using coils or reconstruction with flow diverters.

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.

In vivo response to an implanted shape memory polyurethane foam in a porcine aneurysm model

Cerebral aneurysms treated by traditional endovascular methods using platinum coils have a tendency to be unstable, either due to chronic inflammation, compaction of coils, or growth of the aneurysm. We propose to use alternate filling methods for the treatment of intracranial aneurysms using polyurethane-based shape memory polymer (SMP) foams. SMP polyurethane foams were surgically implanted in a porcine aneurysm model to determine biocompatibility, localized thrombogenicity, and their ability to serve as a stable filler material within an aneurysm. The degree of healing was evaluated via gross observation, histopathology, and low vacuum scanning electron microscopy imaging after 0, 30, and 90 days. Clotting was initiated within the SMP foam at time 0 (<1 h exposure to blood before euthanization), partial healing was observed at 30 days, and almost complete healing had occurred at 90 days in vivo, with minimal inflammatory response.

Patient selection for endovascular treatment of intracranial aneurysms

With recent advancement in medical imaging, techniques, and endovascular tools more patients are diagnosed with unruptured intracranial aneurysms. The main aim of offering aneurysm treatment is to ameliorate the risk of future aneurysm bleeding, while not posing additional risks on the patient from the treatment itself. We discuss in this paper our approach of selecting patients for treatment (simple coiling, balloon-assisted, stent-assisted, vessel sacrifice, or flow-divertion stents). Our decision-making is based on the published data and our center experience. Risks of all option are compared to each other and weighed against natural history of intracranial aneurysms. In this paper, literature is cited and case illustrations are presented to support this approach. Factors that affect our decision-making are aneurysm location, presentation, size, aneurysm geometry, parent vessel anatomy, and relevant co-morbidities.

Endothelial cell proliferation in swine experimental aneurysm after coil embolization

After coil embolization, recanalization in cerebral aneurysms adversely influences long-term prognosis. Proliferation of endothelial cells on the coil surface may reduce the incidence of recanalization and further improve outcomes after coil embolization. We aimed to map the expression of proliferating tissue over the aneurysmal orifice and define the temporal profile of tissue growth in a swine experimental aneurysm model. We compared the outcomes after spontaneous thrombosis with those of coil embolization using histological and morphological techniques. In aneurysms that we not coiled, spontaneous thrombosis was observed, and weak, easily detachable proliferating tissue was evident in the aneurysmal neck. In contrast, in the coil embolization group, histological analysis showed endothelial-like cells lining the aneurysmal opening. Moreover, immunohistochemical and morphological analysis suggested that these cells were immature endothelial cells. Our results indicated the existence of endothelial cell proliferation 1 week after coil embolization and showed immature endothelial cells in septal tissue between the systemic circulation and the aneurysm. These findings suggest that endothelial cells are lead to and proliferate in the former aneurysmal orifice. This is the first examination to evaluate the temporal change of proliferating tissue in a swine experimental aneurysm model.