Coil type does not affect angiographic follow-up outcomes of cerebral aneurysm coiling: a systematic review and meta-analysis

Lumen-oriented versus wall-oriented treatment strategies for intracranial aneurysms - A systematic review of suggested therapeutic concepts

The development of new treatment strategies for intracranial aneurysms (IAs) has been and continues to be a major interest in neurovascular research. Initial treatment concepts were mainly based on a physical-mechanistic disease understanding for IA occlusion (lumen-oriented therapies). However, a growing body of literature indicates the important role of aneurysm wall biology (wall-oriented therapies) for complete IA obliteration. This systematic literature review identified studies that explored endovascular treatment strategies for aneurysm treatment in a preclinical setting. Of 5278 publications screened, 641 studies were included, categorized, and screened for eventual translation in a clinical trial. Lumen-oriented strategies included (1) enhanced intraluminal thrombus organization, (2) enhanced intraluminal packing, (3) bridging of the intraluminal space, and (4) other, alternative concepts. Wall-oriented strategies included (1) stimulation of proliferative response, (2) prevention of aneurysm wall cell injury, (3) inhibition of inflammation and oxidative stress, and (4) inhibition of extracellular matrix degradation. Overall, lumen-oriented strategies numerically still dominate over wall-oriented strategies. Among the plethora of suggested preclinical treatment strategies, only a small minority were translated into clinically applicable concepts (36 of 400 lumen-oriented and 6 of 241 wall-oriented). This systematic review provides a comprehensive overview that may provide a starting point for the development of new treatment strategies.

Efficacy and Safety of Different Bioactive Coils in Intracranial Aneurysm Interventional Treatment, a Systematic Review and Bayesian Network Meta-Analysis

Background: Bioactive coils have been used for nearly 20 years to improve aneurysm treatments. Previous studies are inadequate for comparing the efficacy and safety between different coils. The aim of this study was to investigate the safety and efficacy of different coils by comparing the percentage of people with different modified Raymond scale grades, re-rupture rates, and mortality in patients with intracranial aneurysms embolized with different coils. Method: Randomized controlled trials (RCTs) containing coils for aneurysm interventional treatment were collected from Web of Science, PubMed, and the Cochrane Library up to December 2021. Bayesian network meta-analysis with a randomized or fixed model was performed to compare the efficacy and safety among different bioactive coils and bare platinum coils. Results: We pooled 3362 patients from eight RCTs. No significant differences were found between coils in the proportion of patients with a three-grade classification assessed with the modified Raymond scale immediately after surgery. Hydrogel coils did not show a significant difference in the percentage of patients with a modified Raymond scale grade I postoperatively compared with bare platinum coils (OR, −0.1080; 95% CI, −0.4201–0.2423), but at follow-up, the percentage of patients with modified Raymond scale grade I was significantly higher with hydrogel coils than with bare platinum coils (OR, 0.4957; 95% CI, 0.0060–0.9442). There were no statistical differences between these four coils in terms of aneurysm rupture or re-rupture rate and mortality. Conclusion: Though there was no significant difference in the embolization effect between the several coils in the postoperative period, complete embolization was more likely to be achieved with hydrogel coils compared to bare platinum coils at follow-up. There were no significant differences in safety between the several coil materials.

Safety and Long-Term Efficacy Outcomes for Endovascular Treatment of Wide-Neck Bifurcation Aneurysms of the Middle Cerebral Artery: Insights From the SMART Registry

Introduction

Wide-necked middle cerebral artery bifurcation aneurysms pose specific challenges to endovascular management. Surgical clipping remains the standard treatment approach for these aneurysms in many centers. While recent data suggests the endovascular treatment may be comparable, a prospective datapoint has been lacking.

Materials and Methods

The Penumbra SMART registry, a prospective, multi-center, single-arm outcomes registry of Penumbra coil-treated aneurysms, was queried for endovascularly treated MCA bifurcation aneurysms with wide necks (dome:neck ratio <2 or neck >4 mm). Safety and efficacy outcomes were summarized for ruptured and unruptured aneurysms, including rupture, complication rate, and 1-year occlusion outcomes.

Results

Seventy-two aneurysms across 31 sites were enrolled. Of these, a total of 15 presented as ruptured aneurysms. Serious adverse events were reported in 21 (29.2%) of patients, with 8 (11.1%) attributed to the device/procedure. Immediately postoperatively, 75.0% of cases achieved “adequate” Raymond Roy Class I (40.3%) or II (34.7%) occlusion outcomes. Of the 72 patients treated, 60 (83.3%) underwent follow-up angiography at 1 year, and among these, 95.0% had 1-year occlusion outcomes of Raymond Roy Class I (71.7%) or II (23.3%). A total of 6 aneurysms (10.0%) were required or were planned for retreatment at the last follow-up.

Conclusion

This study represents the most significant prospective sample of endovascularly treated wide-neck MCA bifurcation aneurysms conducted to date. It supports the safety and efficacy of endovascular treatment of these aneurysms.

Injectable Hydrogel Capable of In Situ Covalent Crosslinking for Permanent Embolization

Vascular embolization provides an effective approach for the treatment of hemorrhage, aneurysms, and other vascular abnormalities. However, current embolic materials, such as metallic coils and liquid embolic agents, are limited by their inability to provide safe, consistent, and controlled embolization. Here, we report an injectable hydrogel that can remain at the injection site and subsequently undergo in situ covalent crosslinking, leading to the formation of a dual-crosslinking network (DCN) hydrogel for endovascular embolization. The DCN hydrogel is simple to prepare, easy to deploy via needles and catheters, and mechanically stable at the target injection site, thereby avoiding embolization of nontarget vessels. It possesses efficient hemostatic activity and good biocompatibility. The DCN hydrogel is also clearly visible under X-ray imaging, thereby allowing for targeted embolization. In vivo tests in a rabbit artery model demonstrates that the DCN hydrogel is effective in achieving immediate embolization of the target artery with long-term occlusion by inducing luminal fibrosis. Collectively, the DCN hydrogel provides a viable, biocompatible, and cost-effective alternative to existing embolic materials with clinical translation potential for endovascular embolization.

Control Release and Diffusion-Reaction Kinetics of Genipin-Eluting Fibers Using an in Vitro Aneurysm Flow Model

The minimally invasive treatment of intracranial aneurysms by endovascular coiling is attractive yet faces challenges related to the degradation of fibrin clots in the aneurysm sac over time. Fibrin gels cross-linked with genipin exhibit enhanced mechanical and chemical stability, but there are many unknowns related to best practices for delivery from endovascular devices and subsequent integration of cross-linkers with the nascent clot. Here, we describe the in vitro characterization of genipin-eluting polymer fibers prepared by coextrusion with poly(ethylene-co-vinyl acetate). Genipin incorporation and release from these fibers are characterized by various gravimetric and spectroscopic techniques. Genipin release adheres to Higuchi kinetics with Higuchi constants varying between (2.44 ± 0.83) × 10^-7 and (8.41 ± 0.82) × 10^-7 mol·h^-0.5 depending on genipin loading and vinyl acetate concentration in the polymer matrix. The diffusion-reaction kinetics of genipin released from polymeric fibers within fibrin hydrogels was investigated using an in vitro aneurysm flow model. Spatiotemporal maps of genipin cross-linking density in fibrin gels produced by absorbance measurements suggest that genipin cross-link concentrations up to 9,993.87 ± 909.01 μM can be achieved. This work describes relevant diffusion-reaction parameters of genipin in fibrin gels and establishes the viability of genipin-eluting fibers as a platform for improving endovascular embolization of intracranial aneurysms.

Efficacy of a 14-coil for Framing in Coil Embolization of Small Cerebral Aneurysms

Objective

The purpose of this study was to demonstrate the efficacy of a 14-coil (Target XL) for framing in coil embolization of small cerebral aneurysms.

Methods

Between January 2017 and December 2018, 46 patients underwent coil embolization of a small cerebral aneurysm that was less than 5 mm in maximum diameter. They were categorized into 26 patients in whom only 10-coils were used and 20 in whom Target XL was used for framing. The volume embolization rate (VER) and recanalization rate were compared between the two groups.

Results

Although there were two patients in whom Target XL was replaced with a 10-coil for framing, no adverse events associated with the use of Target XL were noted. The mean VER of the first framing coil was significantly higher in aneurysms that were framed with Target XL than in those framed with a 10-coil (Target XL 22.6 ± 4.5%, 10-coil 17.9 ± 8.4%; p = 0.03). Furthermore, the mean VER at the end of the procedure was significantly higher in aneurysms with Target XL used for framing than in those embolized using only 10-coils (14-coil: 36.8 ± 7.8%, 10-coil: 32.0 ± 6.5%; p = 0.03). No recanalization was observed in aneurysms for which Target XL was used for framing, whereas five aneurysms embolized using only 10-coils were recanalized.

Conclusion

Target XL may be safe and feasible as a framing coil in coil embolization of small cerebral aneurysms, which may result in a high VER, low recanalization rate, and good outcome.

Neurovascular devices for the treatment of intracranial aneurysms: emerging and future technologies

Introduction: Despite numerous advances in the endovascular treatment of intracranial aneurysms (IAs), treatment in cases of wide-neck, complex configurations or branching locations remains challenging. Apart from the paradigm shift introduced by flow diverters, several other devices have seen the light or are under development in order to address these challenges.Areas covered: We performed a review of the novel implantable endovascular devices which have been introduced for the treatment of IAs, from 1 January 2014 to 1 September 2019, excluding classic flow diverter and intracranial stent designs.Expert opinion: Alternative designs have been proposed for the treatment of IAs at branching positions, which do not jail the side branches, with or without flow diversion effect, most of which with good initial outcomes. Endosaccular devices have also been proposed, some of which with lower initial total occlusion rates. Alternative materials such as biopolymers have also been proposed and are under bench research. Despite the challenges in the exploitation of some of the new devices, most of them seem to provide solutions to some current technical shortcomings. The exploitation of the biological phenomena and the physical properties of the devices will allow us to expand the therapeutic armamentarium for more complex IA cases.

TARGET® Intracranial Aneurysm Coiling Prospective Multicenter Registry: Final Analysis of Peri-Procedural and Long-Term Safety and Efficacy Results

Background and Purpose: To describe the final results of the TARGET Registry, a multicenter, real-world study of patients with intracranial aneurysms treated with new generation TARGET Coils.

Methods: The TARGET Registry is a prospective, single-arm study with independent medical event monitoring and core-lab adjudication. Patients with de novo intracranial aneurysms were embolized with either TARGET-360° or helical coils in 12 US centers. The primary outcome was aneurysm packing density (PD), which was assessed immediately post-procedure. The secondary outcomes were immediate and long-term aneurysm occlusion rate using the Raymond Scale, and independent functional outcome using the modified Rankin Scale (mRS). A secondary analysis investigated the influence of the use of 100% 360-complex coils on clinical and angiographic outcomes.

Results: 148 patients with 157 aneurysms met the inclusion and exclusion criteria. 58 (39.2%) patients with ruptured and 90 (61.8%) with unruptured aneurysms were treated using TARGET 360°, helical Coils, or both. Median age was 58.3 (IQR 48.1–67.4), 73% female, and 71.6% were Caucasian. Median follow-up time was 5.9 (IQR 4.0–6.9) months. The majority were treated with TARGET 360-coils (63.7%), followed by mixed and helical coils only. Peri-procedural morbidity and mortality was seen in 2.7% of patients. A good outcome at discharge (mRS 0–2) was seen in 89.9% of the full cohort, and in 84.5 and 93.3% in the ruptured and unruptured patients, respectively. The median packing density was 28.8% (IQR 20.3–41.1). Long-term complete and near complete occlusion rate was seen in 90.4% of aneurysms and complete obliteration was seen in 66.2% of the aneurysms. No significant difference in clinical and angiographic outcomes were noted between the pure 360-complex coiling vs. mixed 360-complex/Helical coiling strategies. In a multivariate analysis, predictors for long-term aneurysm occlusion were aneurysm location, immediate occlusion grade, and aneurysm size. The long-term independent functional outcome was achieved in 128/135 (94.8%) patients and all-cause mortality was seen in 3/148 (2%) patients.

Conclusion: In the multicenter TARGET Registry, two-thirds of aneurysms achieved long-term complete occlusion and 91.0% achieved complete or near complete occlusion with excellent independent functional outcome.

Clinical Trial Registration:www.ClinicalTrials.gov, identifier: NCT01748903

Endovascular Metal Devices for the Treatment of Cerebrovascular Diseases

Cerebrovascular disease involves various medical disorders that obstruct brain blood vessels or deteriorate cerebral circulation, resulting in ischemic or hemorrhagic stroke. Nowadays, platinum coils with or without biological modification have become routine embolization devices to reduce the risk of cerebral aneurysm bleeding. Additionally, many intracranial stents, flow diverters, and stent retrievers have been invented with uniquely designed structures. To accelerate the translation of these devices into clinical usage, an in-depth understanding of the mechanical and material performance of these metal-based devices is critical. However, considering the more distal location and tortuous anatomic characteristics of cerebral arteries, present devices still risk failing to arrive at target lesions. Consequently, more flexible endovascular devices and novel designs are under urgent demand to overcome the deficiencies of existing devices. Herein, the pros and cons of the current structural designs are discussed when these devices are applied to the treatment of diseases ranging broadly from hemorrhages to ischemic strokes, in order to encourage further development of such kind of devices and investigation of their use in the clinic. Moreover, novel biodegradable materials and drug elution techniques, and the design, safety, and efficacy of personalized devices for further clinical applications in cerebral vasculature are discussed.

Endovascular coiling for cerebral aneurysm: single-center experience in Egypt

Background

Endovascular management for cerebral saccular aneurysm has evolved in the last decade with evolution in both equipment and material. Coiling is still the mainstay of cerebral aneurysm endovascular management. In Egypt, practice outcome needs evaluation especially at low-volume centers.

Purpose

To discuss the technical and management outcomes of our first symptomatic and asymptomatic cerebral saccular aneurysm case series treated with simple coiling.

Patients and methods

Clinical, treatment, and outcome variables of consecutive symptomatic and asymptomatic cerebral aneurysm cases treated with simple coiling between January 2011 and June 2016 in one center were analyzed.

Results

In 31 patients, 35 aneurysms were found, 34 aneurysms (97.1%) were treated by endovascular coiling, and only one aneurysm (2.9%) was not fit for endovascular treatment. Total occlusion was achieved in 29 aneurysms (82.9%). Neck remnants were present in 4 aneurysms (11.4%). Partial coiling (incomplete occlusion) was achieved in 1 aneurysm (2.9%). Regarding functional outcome (mRS at discharge), 25 patients had good outcome (mRS = 0, 1, 2, 3) and 6 patients had poor outcome (mRS = 4, 5, 6).

Conclusion

The endovascular coiling could be used as a first-choice option for treatment of saccular cerebral aneurysms at our center despite the low case rate.

Hydrogel coils versus bare platinum coils for the endovascular treatment of intracranial aneurysms: a meta-analysis of randomized controlled trials

Background

Recent studies have shown conflicting results regarding the effect of hydrogel coils for treating intracranial aneurysm compared to bare platinum coils. We implemented a meta-analysis to assess the value of hydrogel coils in intracranial aneurysm treatment.

Methods

The MEDLINE, EMBASE, and Cochrane Library databases were searched for randomized controlled trials (RCTs) which had evaluated hydrogel coils versus bare platinum coils for intracranial aneurysms.

Results

We pooled 1526 patients from 4 RCTs with the mean follow-up time of more than 16 months. Hydrogel coils had reductions on mid-term recurrence (RR 0.78, 95% CI 0.65 to 0.94, P = 0.008) and residual aneurysm (RR 0.71, 95% CI 0.57 to 0.88, P = 0.002), but didn’t show any significant differences in other favorable outcomes such as functional recovery, mortality and so on. In the subgroup analysis, we found that second-generation hydrogel coils might exhibit potential impacts on increasing mid-term complete occlusion (RR 1.26, 95% CI 1.07 to 1.48, P = 0.005) and decreasing residual aneurysm neck. (RR 0.54, 95% CI 0.34 to 0.86, P = 0.010).

Conclusions

Hydrogel coils showed no significant efficacy on functional recovery but exhibited a lower rate of recurrences and residual aneurysms in patients with intracranial aneurysms.

Electronic supplementary material

The online version of this article (10.1186/s12883-018-1171-8) contains supplementary material, which is available to authorized users.

Importance of the First Coil in the Embolization of Intracranial Aneurysms : A Case Control Study

PURPOSE

Endovascular therapy for the treatment of cerebral aneurysms has a higher incidence of rebleeding and a lower occlusion rate than microsurgical clipping. This study investigated whether first coil volume packing density (1st VPD) and first loop diameter of the first coil (1st LD) are associated with recanalization after endovascular coiling.

METHODS

The study included 174 initial saccular aneurysm cases from 2010 to 2015. Between the recanalization and non-recanalization groups, we compared age, sex, aneurysm location, rupture occurrence, shape, maximum aneurysm size, neck width, dome-to-neck ratio, aneurysm volume, coil volume, VPD, 1st VPD, 1st LD, relation of the first loop diameter of the first coil and the maximum aneurysm size (RLAS), types of assistance techniques, and the Raymond scale score at initial and follow-up angiography.

RESULTS

Recanalization occurred in 41 cases (23.6%). The factors associated with recanalization were irregular shape, maximum aneurysm size, neck width, dome-to-neck ratio, aneurysm volume, VPD, 1st VPD and 1st LD smaller than the maximum aneurysm size. The cut-off values for aneurysmal recanalization were 92%, 11% and 37% for RLAS, 1st VPD and VPD, respectively.

CONCLUSION

The 1st VPD and 1st LD were associated with aneurysmal recanalization after embolization. These factors provide a helpful index for coil programming.

A new combined parameter predicts re-treatment for coil-embolized aneurysms: a computational fluid dynamics multivariable analysis study

Purpose

Coil embolization is a minimally invasive method used to treat cerebral aneurysms. Although this endovascular treatment has a high success rate, aneurysmal re-treatment due to recanalization remains a major problem of this method. The purpose of this study was to determine a combined parameter that can be useful for predicting aneurysmal re-treatment due to recanalization.

Methods

Patient-specific geometries were used to retrospectively analyze the blood flow for 26 re-treated and 74 non-retreated aneurysms. Post-operatively aneurysms were evaluated at 12-month follow-up. The hemodynamic differences between the re-treatment and non-retreatment aneurysms were analyzed before and after coil embolization using computation fluid dynamics. Basic fluid characteristics, rates of change, morphological factors of aneurysms and patient-specific clinical information were examined. Multivariable analysis and logistic regression analysis were performed to determine a combined parameter—re-treatment predictor (RP).

Results

Among examined hemodynamic, morphological, and clinical parameters, slight reduction of blood flow velocity rate in the aneurysm, slight increase of pressure rate at the aneurysmal neck and neck area, and hypertension were the main factors contributing to re-treatment. Notably, hemodynamic parameters between re-treatment and non-retreatment groups before embolization were similar: however, we observed significant differences between the groups in the post-embolization average velocity and the rate of reduction in this velocity in the aneurysmal dome.

Conclusions

The combined parameter, RP, which takes into consideration hemodynamic, morphological, and clinical parameters, accurately predicts aneurysm re-treatment. Calculation of RP before embolization may be able to predict the aneurysms that will require re-treatment.

Optimal first coil selection to avoid aneurysmal recanalization in endovascular intracranial aneurysmal coiling

BACKGROUND

Aneurysmal recanalization is a problem with endovascular coiling and one of its risk factors is the low volume embolization ratio (VER). The first coil VER (1st VER) is believed to be critical for obtaining a high VER. The main objective of this study was to evaluate factors potentially useful for selecting the optimal 1st VER for endovascular coiling.

METHODS

609 initial saccular aneurysmal treatments performed between January 2010 and December 2014 at our institution were included in this retrospective study. Attempted procedures, retreatment cases, intraoperative rupture cases, and stent-assisted coiling cases were excluded. Age, sex, aneurysm location, ruptured aneurysm, aneurysm shape, neck size, maximum aneurysm size, dome-to-neck ratio, aneurysm volume, procedure, immediate Raymond scale score, 1st VER, and VER between the recanalization groups and non-recanalization groups were compared.

RESULTS

The factors related to recanalization were ruptured aneurysms, neck width, maximum aneurysm size, aneurysm volume, procedure, 1st VER, and VER. The cut-off values for aneurysm recanalization were a 1st VER of 10.0% and a VER of 33.0%. The maximum average VER of normal size aneurysms was found in the groups with a 1st VER of 17.5-20.0%.

CONCLUSIONS

1st VER was found to be a helpful index for estimating aneurysmal recanalization after coil embolization. The target 1st VER was 17.5-20.0% for obtaining a higher VER and avoiding recanalization.

Safety and effectiveness of large volume coils in the treatment of small aneurysms

BACKGROUND AND PURPOSE

Large volume soft design coils facilitate quicker aneurysm filling and high packing density. Our purpose was to analyze the feasibility, safety, and effectiveness of the Penumbra Coil 400 (PC400) system in the treatment of small aneurysms.

MATERIALS AND METHODS

A retrospective analysis of prospective data collected at three different centers was performed on consecutive aneurysms <10 mm treated with the PC400 system. A total of 92 aneurysms were included in the study. Feasibility, procedure safety, angiographic and clinical results, and follow-up results were evaluated.

RESULTS

Mean aneurysm size was 5.8±2.0 mm. An average of 2.5±1.3 coils with a mean length of 18±16 cm per aneurysm was used, resulting in a mean packing density of 45.6±14.4%. The thromboembolic event rate was 3.3% and no procedural aneurysm rupture was observed. Immediate adequate occlusion was achieved in 66% of aneurysms. During a mean follow-up period of 7.4 months the number of adequate occlusions increased to 91%.

CONCLUSIONS

Large volume PC 400 coils are safe and effective in the treatment of small aneurysms with a low thromboembolic complication rate and no hemorrhagic events. High packing densities are achieved with a low average number of coils used per aneurysm treated. The aneurysms demonstrated progressive occlusion over time, which probably suggests stability in the long term.

Improvement in patient outcomes following endovascular treatment of WFNS grade V subarachnoid haemorrhage from 2000 to 2014

Patient outcomes following grade V subarachnoid haemorrhage (SAH) have been dismal, although they may have improved following recent technological advances in endovascular treatment (EVT). A single-centre, retrospective study was conducted to evaluate whether outcomes have improved from 2000 to 2014 for patients with World Federation of Neurosurgical Societies (WFNS) grade V SAH. Coiling has been the preferred first-line treatment for grade V SAH patients in our institution since 2000. Patients who underwent EVT (n=115) were grouped on the basis of their hospital admission year: 2000-2004 (n=44), 2005-2009 (n=37) and 2010-2014 (n=34). Patient demographics, outcomes and in-hospital mortality rates were compared between the groups. Patient outcomes at discharge were evaluated using the Glasgow Outcome Scale (GOS), with GOS scores of 4-5 defined as favourable outcomes. There were no significant intergroup differences in patient demographics. In addition, there were no significant differences in the frequencies of favourable outcomes (14% in 2000-2004, 16% in 2005-2009 and 26% in 2010-2014). Mortality rates were 52% in 2000-2004, 43% in 2005-2009 and 24% in 2010-2014, with a significantly lower mortality rate in 2010-2014 than in 2000-2004 (p=0.01). Both perioperative rebleeding and delayed cerebral ischaemia decreased over time; however, multivariate regression analysis showed that the former contributed more to the decrease in mortality. Age was the only variable associated with favourable outcomes. The results of this study indicate that EVT is an appropriate therapeutic option for grade V SAH patients. However, multi-centre, prospective trials are required to provide evidence-based verification of the efficacy of EVT.

Bioactive versus bare platinum coils for the endovascular treatment of intracranial aneurysms: systematic review and meta-analysis of randomized clinical trials

Background

Bioactive coils were introduced in 2002 in an attempt to improve aneurysm healing and durability of angiographic results. Evidence demonstrating superior efficacy to justify the routine use of bioactive coils over bare coils is limited. We compared the periprocedural and clinical outcome after bioactive and bare platinum coiling for intracranial aneurysms.

Methods

MEDLINE, EMBASE, Cochrane Library, and ISI Web of Knowledge Conference Proceedings Citation Index—Science were searched for randomized clinical trials (RCTs) comparing bioactive and bare coils. The methodological quality was evaluated to assess bias risk. Periprocedural outcomes and mid-term outcomes were compared.

Results

Five independent RCTs comparing bioactive (n=1084) and bare coils (n=1084) were identified. Periprocedural outcome was similar for both groups. Bioactive coiling increased the rate of complete aneurysm occlusion (47% vs 40%; RR 1.17 (95% CI 1.05 to 1.31); p=0.006) and reduced the rate of residual aneurysm neck at 10 months compared with bare coiling in the mid-term (26% vs 31%; RR 0.82 (95% CI 0.70 to 0.96); p=0.01). There were no differences in aneurysm recurrence, aneurysm rupture, stroke, neurological death, modified Rankin Scale score and reinterventions. Subgroup analysis for the three RCTs on hydrogel coils demonstrated reduction of residual aneurysms compared with bare coiling (25% vs 34%; RR 0.76 (95% CI 0.58 to 0.99); p=0.04).

Conclusions

Bioactive coils ensure a higher rate of medium-term complete aneurysm occlusion while reducing the rate of residual neck aneurysms compared with bare coiling in the mid-term. Hydrogel coils reduce residual aneurysms compared with bare coils. While there is level 1a evidence to show more complete aneurysm occlusion, longer term follow-up is needed to determine if this translates into clinical significance.

HydroCoils Are Associated with Lower Angiographic Recurrence Rates Than Are Bare Platinum Coils in Treatment of "Difficult-to-Treat" Aneurysms: A Post Hoc Subgroup Analysis of the HELPS Trial

BACKGROUND AND PURPOSE

The HydroCoil Endovascular Aneurysm Occlusion and Packing Study was a randomized controlled trial that compared HydroCoils to bare platinum coils. Using data from this trial, we performed a subgroup analysis of angiographic and clinical outcomes of patients with "difficult-to-treat" aneurysms, defined as irregularly shaped and/or having a dome-to-neck ratio of <1.5.

MATERIALS AND METHODS

Separate subgroup analyses comparing outcomes of treatment with HydroCoils to that of bare platinum coils were performed for the following: 1) irregularly shaped aneurysms, 2) regularly shaped aneurysms, 3) aneurysms with a dome-to-neck ratio of <1.5, and 4) aneurysms with a dome-to-neck ratio of ≥1.5. For each subgroup analysis, the following outcomes were studied at the last follow-up (3-18 months): 1) any recurrence, 2) major recurrence, 3) re-treatment, and 4) an mRS score of ≤2. Multivariate logistic regression analysis was performed to determine if the HydroCoil was independently associated with improved outcomes in these subgroups.

RESULTS

Among the patients with an irregularly shaped aneurysm, the HydroCoil was associated with lower major recurrence rates than the bare platinum coils (17 of 66 [26%] vs 30 of 69 [44%], respectively; P = .046). Among the patients with an aneurysm with a small dome-to-neck ratio, the HydroCoil was associated with lower major recurrence rates than the bare platinum coils (18 of 73 [24.7%] vs 32 of 76 [42.1%], respectively; P = .02). No difference in major recurrence was seen between HydroCoils and bare platinum coils for regularly shaped aneurysms (42 of 152 [27.6%] vs 52 of 162 [32.1%], respectively; P = .39) or aneurysms with a large dome-to-neck ratio (41 of 145 [28.3%] vs 50 of 155 [32.3%], respectively; P = .53).

CONCLUSIONS

This unplanned post hoc subgroup analysis found that HydroCoils are associated with improved angiographic outcomes in the treatment of irregularly shaped aneurysms and aneurysms with a dome-to-neck ratio of <1.5. Because this was a post hoc analysis, these results are not reliable and absolutely should not alter clinical practice but, rather, may inform the design of future randomized controlled trials.

Follow-up of cerebral aneurysm embolization with hydrogel embolic system: Systematic review and meta-analysis

BACKGROUND

Hydrogel embolic system (HES) for endovascular treatment of cerebral aneurysms was developed to reduce the risk of aneurysm recurrence and the rate of retreatment. The aim of this systematic review was to verify the efficacy of HES, also in comparison to bare platinum coils (BPC).

MATERIAL AND METHODS

A systematic literature search was performed by two independent reviewers for articles published until January 31st, 2013 on the follow-up recurrence rate of intracranial aneurysm embolization with hydrogel-coated coils.

RESULTS

Thirteen articles on the use of HES for embolization of cerebral aneurysms were included in this study, for a total of 1683 embolized aneurysms. Significant heterogeneity was found regarding patient populations, methods of aneurysm coiling, follow-up schedules, and recurrence definitions. The pooled rate of initial complete aneurysm occlusion was 55% (95%CI, 38-70%); 59% (95%CI, 43-74%) in the subgroup of aneurysms treated with the use of HES. The pooled total recurrence rate was 19% (95%CI, 15-24%); 17% (95%CI, 14-22%) in the HES-treated subgroup. The pooled major recurrence rate was 12% (95%CI, 8-18%); 11% (95%CI, 7-16%) in the HES-treated subgroup. Comparing both types of coils, the pooled odds ratio for total recurrence was 0.63 (95%CI, 0.45-0.88; p=0.008) in favor of HES.

CONCLUSIONS

Embolization of cerebral aneurysms using HES seems to result in a lower rate of recurrence than that obtained using BPC, which is in line with the only randomized controlled trial. High-quality prospective studies are needed to define specific indications for the use of hydrogel-coated coils.

Comparison of Intracranial Aneurysms Treated by 2-D Versus 3-D Coils: A Matched-Pairs Analysis

OBJECTIVE

Knowledge on the influence of 2D and 3D coils to occlude intracranial aneurysms is poor. Therefore, aim of our analysis was to evaluate whether the use of 3-D versus 2-D coils alone may improve the efficacy of endovascular aneurysm treatment.

PATIENTS AND METHODS

We performed a matched pair analysis comparing aneurysms treated by 3-D coils as initial "framing" coils to aneurysms treated exclusively by 2-D coils. Number of coils, implanted coil length/volume, and associated packing density were calculated. Aneurysmal occlusion was assessed and monitored 6 months (DSA; magnetic resonance angiography (MRA)) and 18 months (MRA) after embolization. Periprocedural complications and retreatment rate of each group were analyzed.

RESULTS

Our retrospective analysis revealed 50 pairs. Concerning the 3-D group, number of coils (353 in total, median 7; p = 0.002), implanted coil length (55.69  ± 48.4 cm), implanted coil length per volume (5.92 mm/mm³), and packing density (30 %; p = 0.017) was higher than in the 2-D group (259 in total, median 5 coils; 38.52 ± 43.13 cm; 4.54 mm/mm³; 23 %). Occlusion was not significantly different immediately after treatment but at 6 and 18 months follow-up in favor of 3-D coils. Retreatment was performed in 2 cases of the 3-D group and in 3 cases of the 2-D group and therefore in a similar range (p = 0.564).

CONCLUSION

Initial use of 3-D coils revealed a higher packing density and a higher long-term occlusion. Therefore, we recommend initial use of 3-D coils.

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.

Aneurysm Recurrence Volumetry Is More Sensitive than Visual Evaluation of Aneurysm Recurrences

PURPOSE

Considerable inter-observer variability in the visual assessment of aneurysm recurrences limits its use as an outcome parameter evaluating new coil generations. The purpose of this study was to compare visual assessment of aneurysm recurrences and aneurysm recurrence volumetry with an example dataset of HydroSoft coils (HSC) versus bare platinum coils (BPC).

METHODS

For this retrospective study, 3-dimensional time-of-flight magnetic resonance angiography datasets acquired 6 and 12 months after endovascular therapy using BPC only or mainly HSC were analyzed. Aneurysm recurrence volumes were visually rated by two observersas well as quantified by subtraction of the datasets after intensity-based rigid registration.

RESULTS

A total of 297 aneurysms were analyzed (BPC: 169, HSC: 128). Recurrences were detected by aneurysm recurrence volumetry in 9 of 128 (7.0 %) treated with HSC and in 24 of 169 (14.2 %) treated with BPC (odds ratio: 2.39, 95 % confidence interval: 1.05-5.48; P = 0.039). Aneurysm recurrence volumetry revealed an excellent correlation between observers (Cronbach's alpha = 0.93). In contrast, no significant difference in aneurysm recurrence was found for visual assessment (3.9 % in HSC cases and 4.7 % in BPC cases). Recurrences were observed in aneurysms smaller than the sample median in 10 of 33 (30.3 %) by aneurysm recurrence volumetry and in 1 of 13 (7.7 %) by visual assessment.

CONCLUSIONS

Aneurysm recurrences were detected more frequently by aneurysm recurrence volumetry when compared with visual assessment. By using aneurysm recurrence volumetry, differences between treatment groups were detected with higher sensitivity and inter-observer validity probably because of the higher detection rate of recurrences in small aneurysms.

Analysis of early angiographic outcome using unique large diameter coils in comparison with standard coils in the embolization of cerebral aneurysms: a retrospective review

BACKGROUND

The initial experience with the large diameter Penumbra Coil 400 (PC400) system has been positive regarding safety, efficacy, improved packing density and cost effectiveness, but follow-up data are limited.

METHODS

This is a single-center retrospective review of 76 aneurysms treated with PC400 coils compared with 301 aneurysms treated with a variety of different bare platinum and bioactively coated coils. Atypical and giant aneurysms were excluded as well as those that had undergone previous treatment. Occlusion classification was determined immediately after the procedure and at short-term follow-up.

RESULTS

Compared with controls, in the PC400 group fewer coils were used (3.53 vs 5.44, p<0.05), procedure time was decreased (48 vs 64 min, p<0.05) and packing density was increased (31.7% vs 24.8%, p<0.05). There were more grade III aneurysms (71.1% vs 38.2%, p<0.05) and fewer grade I aneurysms (13.2% vs 30.2%, p<0.05) in the PC400 group than in the control group immediately after the procedure. At first follow-up, however, more aneurysms in the PC400 group improved (51.3% vs 28.7%, p<0.05) in angiographic grade leading to similar rates of acceptable outcome (grades I or II) at first follow-up (PC400 79.5% vs control 77.2%). The adverse event rate was similar in the two groups.

CONCLUSIONS

Large diameter PC400 coils can be used to safely treat cerebral aneurysms with fewer coils, decreased procedure time and increased packing density compared with standard coils. The early angiographic outcome is similar to that achieved with standard coils.

Endovascular treatment of cerebral aneurysms using the hydrocoil embolic system

HydroCoils are platinum helical coils coated with a layer of hydrophilic acrylic polymer (hydrogel), which on contact with blood causes disentanglement of polymer chains and expansion. We retrospectively reviewed a series of 29 patients harboring 29 cerebral aneurysms treated with the Hydrocoil Embolic System in the period 2004-2005, discussing the results of endovascular procedures in terms of safety and efficacy. The immediate post-procedure angiographic control demonstrated complete aneurysm occlusion in 21 cases (72.4%), near-complete occlusion in seven cases (24.1%), whereas in one case (3.4%) there was a procedure failure with major perfusion of the sac. Five patients (17.2%) experienced thromboembolic complications, including an asymptomatic lacunar stroke of the head of the caudate nucleus, a thalamic infarct following hypotension secondary to pulmonary edema, temporal ischemia secondary to vasospasm and a small right occipital ischemic lesion. Only one patient (3.4%) suffered a major ischemic accident. No other procedure-related complication occurred. Three-month follow-up control with MR angiography and 12-month follow-up angiography demonstrated no recurrence of aneurysms. Overall, after a mean follow-up of 12 months, the clinical outcome was good recovery in 26 patients (89.6%), moderate disability in three patients (10.3%) and no vegetative status or death. Our HydroCoil series supports the safety and midterm durability of hydrogel-coated aneurysm coils in the treatment of cerebral aneurysms.