Safety and predictors of aneurysm retreatment for remnant intracranial aneurysm after initial endovascular embolization

Haemorrhagic stroke and brain vascular malformations in women: risk factors and clinical features

Haemorrhagic stroke is a severe condition with poor prognosis. Biological sex influences the risk factors, presentations, treatment, and patient outcomes of intracerebral haemorrhage, aneurysmal subarachnoid haemorrhage, and vascular malformations. Women are usually older at onset of intracerebral haemorrhage compared with men but have an increased risk of aneurysmal subarachnoid haemorrhage as they age. Female-specific factors such as pregnancy, eclampsia or pre-eclampsia, postmenopausal status, and hormone therapy influence a woman's long-term risk of haemorrhagic stroke. The presence of intracranial aneurysms, arteriovenous malformations, or cavernous malformations poses unique clinical dilemmas during pregnancy and delivery. In the absence of evidence-based guidelines for managing the low yet uncertain risk of haemorrhagic stroke during pregnancy and delivery in women with vascular malformations, multidisciplinary teams should carefully assess the risks and benefits of delivery methods for these patients. Health-care providers should recognise and address the challenges that women might have to confront when recovering from haemorrhagic stroke.

Progression from Early Minor Recanalization to Major Recanalization in Ruptured Intracranial Aneurysms After Successful Coil Embolization: Risk Factors and Proposal of a Novel Predicting Variable

BACKGROUND

The risk factors for the progression from early minor recanalization to major recanalization are not well established. Herein, we evaluated ruptured intracranial aneurysms (IAs) with minor recanalization within 1 year of coiling and their progression to major recurrence.

METHODS

We retrospectively reviewed our database of coiled IAs and searched for ruptured saccular IAs that were successfully embolized without residual sacs. We selected IAs with minor recanalization confirmed on radiological studies within 1 year of coil embolization. All the IA cases had a follow-up period longer than 36 months based on the radiological results.

RESULTS

Minor recanalization occurred in 45 IAs within 1 year of coil embolization. Among them, 14 IAs (31.1%) progressed to major recanalization, and 31 remained stable. Progression to major recanalization was detected 12 months after minor recanalization in 2 patients, 24 months in 7 patients, and 36 months in 5 patients. Moreover, the progression to major recanalization occurred more frequently in IAs at the posterior location (P = 0.024, odds ratio 11.20) and IAs with a proportional forced area > 9 mm2 (P = 0.002, odds ratio 17.13), which was a newly proposed variable in the present study.

CONCLUSIONS

Our results showed that approximately one third of the ruptured IAs with early minor recanalization after coiling progressed to major recanalization within 3 years. Physicians should focus on the progression of ruptured IAs from minor to major recanalization, especially those with a posterior circulation location and a proportional forced area >9 mm2.

Cost-effectiveness of WEB Embolization, Coiling and Stent-assisted Coiling for the Treatment of Unruptured Intracranial Aneurysms

PURPOSE

Information about the cost-effectiveness of a certain treatment is relevant for decision-making and healthcare providers. This study compares the cost-effectiveness of the novel Woven Endobridge (WEB) for intracranial aneurysm treatment with conventional coiling and stent-assisted coiling (SAC) from the perspective of the German Statutory Health Insurance.

METHODS

A patient-level simulation was constructed to simulate 55-year-old patients with an unruptured middle cerebral artery aneurysm (size: 3-11 mm) considering WEB treatment, coiling or SAC in terms of morbidity, angiographic outcome, retreatment, procedural and rehabilitation costs and rupture rates. Incremental cost-effectiveness ratios (ICERs) were calculated as costs per quality-adjusted life years (QALYs) and costs per year with neurologic morbidity avoided. Uncertainty was explored with deterministic and probabilistic sensitivity analyses. The majority of data were obtained from prospective multi-center studies and meta-analyses of non-randomized studies.

RESULTS

In the base case, lifetime QALYs were 13.24 for the WEB, 12.92 for SAC and 12.68 for coiling. Lifetime costs were 20,440 € for the WEB, 23,167 € for SAC, and 8200 € for coiling. Compared to coiling, the ICER for the WEB was 21,826 €/QALY, while SAC was absolutely dominated by WEB. Probabilistic sensitivity analysis revealed that at a willingness-to-pay of ≥ 30,000 €/QALY, WEB was the preferred treatment. Deterministic sampling showed that the discount rate, material costs and retreatment rates had the largest impact on the ICERs.

CONCLUSION

The novel WEB showed at least comparable cost-effectiveness to SAC for treatment of broad-based unruptured aneurysms. Considering all three modalities, coiling had the least costs; however this modality is often not appropriate for the treatment of wide-necked aneurysms.

Management of aneurysmal recurrence after Woven EndoBridge (WEB) treatment

BACKGROUND

Around 10% of Woven EndoBridge device (WEB)-treated intracranial aneurysms will need retreatment, and it is generally believed to be more challenging than retreatment after an initial coiling. We aim to report retreatment strategies and outcomes after initial WEB embolizations.

METHODS

Databases from four treatment centers, containing consecutive aneurysms treated with a WEB between 2013 and 2022, were reviewed. Demographics, aneurysm characteristics, retreatment strategies and outcomes were collected and analyzed.

RESULTS

From a 756 WEB database, 57 aneurysms were included. The global retreatment rate was 7.5% (95% CI 5.6% to 9.4%). The retreatment rate was significantly higher in the ruptured compared with the unruptured population (13% vs 3.9%, respectively, P<0.0001). Aneurysms were retreated on average 21.2 months after the initial WEB treatment (range 4.8-70 months). Surgery was performed in 11% and endovascular treatment in 89% of cases, consisting of flow diversion (48%), stent-assisted coiling (30%), coiling (12%), and second WEB placement (10%). Imaging follow-up was available in 88% of all WEB retreatments (50/57) (average 17 months, 49% digital subtraction angiography), demonstrating complete occlusion in 56% and 'adequate' occlusion in 88%. Morbidity was 5.3% (95% CI 0% to 12.0%) and mortality 0%. No patient experienced rebleeding during the follow-up period.

CONCLUSION

The retreatment rate after an initial WEB treatment seems to compare favorably with that of coiling. Endovascular treatment of recurrence following WEB implantation is feasible in most situations; it generally requires the use of a stent and leads to a high rate of satisfactory occlusion.

Long-Term Follow-up of Aneurysms Treated With Hydrogel-Coated Coils Shows Progressive Thrombosis and Improvement in Raymond-Roy Classification

BACKGROUND

Coil embolization of aneurysms has been shown to be a safe and effective method of aneurysm treatment. Hydrogel-coated coils were developed as a hybrid embolization device to increase the packing density of a coil mass in an aneurysm and to reduce retreatment and rerupture rates. Previous studies have shown a benefit compared with bare metal coils.

OBJECTIVE

To present long-term follow-up of a cohort of patients treated with hydrogel-coated coils to better determine the effectiveness compared with bare platinum coils.

METHODS

Between January 2003 and April 2012, we identified patients with both ruptured and unruptured aneurysms coiled at our institution, using some portion of hydrogel-coated coils. Planned follow-up angiography was performed at 6 months, 18 months, and 5 years post-treatment. All imaging was independently adjudicated by a single physician at a separate institution. The results were scored with the modified Raymond-Roy Occlusion Classification.

RESULTS

A total of 145 patients with 153 treated aneurysms were included in the study analysis. Immediately after treatment, 49% of aneurysms were classified at Raymond-Roy Occlusion Classification I or II, which improved to 83% by 6 months. This percent plateaued at 18-month and 5-year follow-up, measuring 86% and 90%, respectively. The retreatment rate was 14% over the 5-year period, and there were no rerupture events captured.

CONCLUSION

Treatment of intracranial aneurysms with coil embolization using hydrogel-coated aneurysms shows evidence of progressive occlusion, particularly over the first 6 months of follow-up. The retreatment rate is comparable with historical data, and the rerupture rate is low.

Risk factors for recanalization of dense coil packing for unruptured cerebral aneurysms in endovascular coil embolization: Analysis of a single center's experience

In coil embolization of cerebral aneurysms, inadequate packing is known to increase the probability of recanalization. Even tightly embolized aneurysms may be recanalized, but predictive factors for recanalization have not been fully investigated. This retrospective study aimed to identify risk factors for recanalization of treated aneurysms with a volume embolization ratio (VER) ≥ 25%. A total of 301 unruptured aneurysms in 248 patients who underwent coil embolization between March 2012 and January 2021 were analyzed. Cases involving dissecting aneurysm, intraluminal thrombosis, parent artery occlusion, intraoperative rupture, re-treatment, rupture the day after surgery, postoperative coil migration, and postoperative parent artery occlusion were excluded due to the inaccuracy of VER. A total of 105 aneurysms (34.9%) treated with VER ≥ 25% were extracted. Clinical features (age, sex, medical history, family history), anatomical features (shape, location, aneurysm size, inflow angle, and volume), procedural features (stent-assisted, Raymond-Roy occlusion classification [RROC] immediately after treatment, re-treatment rate), and follow-up period were compared between Recanalization and Non-recanalization groups. Predictors of recanalization were determined using logistic regression and receiver operating characteristic (ROC) curve analyses. Eleven aneurysms were recanalized. In multivariate analysis, RROC class 3 (odds ratio [OR] 11.0; 95% confidence interval [CI] 2.03-59.4) and aneurysm volume (OR 1.005; 95%CI 1.001-1.008) were independent predictors of recanalization. ROC curve analysis showed optimal cutoff values for aneurysm volume of 69.5 mm³ (sensitivity, 81.8%; specificity, 72.3%). In coil embolization of unruptured aneurysms that VER ≥ 25%, cases with RROC class 3 or high aneurysm volume may be associated with a higher risk of recanalization, and should be carefully followed-up.

Sex Differences in Cerebral Aneurysms and Subarachnoid Hemorrhage

Sex differences in cerebral aneurysm occurrence and characteristics have been well described. Although sex differences in outcomes following ischemic stroke have been identified, the effect of sex on outcomes following hemorrhagic stroke, and in particular, aneurysm treatment has been less studied. We describe the current state of knowledge regarding the impact of sex on treatment and outcomes of cerebral aneurysms. Although prior studies suggest that aneurysm prevalence and progression may be related to sex, we did not find clear evidence that outcomes following subarachnoid hemorrhage vary based on sex. Last, we identify areas for future research that could enhance understanding of the role sex plays in this context.

Endovascular treatment of ruptured anterior communicating aneurysms: a 17-year institutional experience with coil embolization

BACKGROUND

Ruptured anterior communicating artery (ACoA) aneurysms can be challenging to treat via an endovascular procedure. This study analyzed retreatment rates and neurological outcomes associated with ruptured ACoA aneurysms treated via endovascular coiling.

METHODS

All patients with a ruptured ACoA aneurysm treated with endovascular coiling from 2003 to 2019 were retrospectively analyzed at a single center. Two comparisons were performed: no retreatment versus retreatment and coil embolization versus balloon-assisted coil embolization. Outcomes included retreatment and neurological outcome assessed via modified Rankin Scale (mRS).

RESULTS

During the study period, 186 patients with ruptured ACoA aneurysms underwent coil embolization. Treatment included standard coil embolization (68.3%, n=127), balloon-assisted coiling (28.5%, n=53), and stent-assisted embolization (2.7%, n=5). Angiographic outcomes were as follows: class I, 65.1% (n=121); class II, 28.5% (n=53); and class III, 6.5% (n=12). There were no aneurysm reruptures after the index procedure. The mean (SD) mRS score was 2.7 (2.0) at last follow-up (mortality, 19 (10%)). Retreatment occurred in 9.7% (n=18). Patients with retreatment were younger with lower-grade subarachnoid hemorrhage and more favorable functional status at discharge. Patients with aneurysms >7 mm (n=36) were significantly more likely to have recurrence (22.2% vs 6.7%, P=0.005).

CONCLUSIONS

Endovascular treatment of ruptured ACoA aneurysms is safe and is associated with low mortality and retreatment rates. Younger patients with favorable functional status and larger aneurysm size are more likely to be retreated. Ruptured aneurysms <4 mm, although prevalent in the study (29%), never required retreatment.

Development and validation of a predictive model for the prognosis in aneurysmal subarachnoid hemorrhage

Background

This study was to conduct a predictive model for the prognosis of aneurysmal subarachnoid hemorrhage (aSAH) and validate the clinical data.

Methods

A total of 235 aSAH patients were enrolled in this study, dividing into the favorable or poor prognosis groups based on Modified Rankin Scale (mRS) at 3 months postoperatively. Multivariate analysis was assessed using binary Logistic regression and Fisher discriminant analysis. The receiver operating characteristic (ROC) curve was used to determine the cut‐off value.

Results

Our findings showed that the high Glasgow Coma Scale (GCS) score 24‐hour after surgery reduced the risk of poor prognosis, and the surgical clipping and elevated neutrophil‐lymphocyte ratio (NLR) increased the risk of poor prognosis. The discriminant function was V = 0.881 × GCS score − 0.523 × NLR − 0.422 × therapeutic approach, and V = −0.689 served as a cut‐off value. When V ≥ −0.689, the good prognosis was considered among these patients with aSAH. The correctness for predicting the prognostic outcomes by self‐validation was 85.11%.

Conclusion

This predictive model established by a discriminant analysis is a useful tool for predicting the prognostic outcomes of aSAH patients, which may help clinicians identify patients at high risk for poor prognosis and optimize treatment after surgery.

Clip-first policy versus coil-first policy for the exclusion of middle cerebral artery aneurysms

OBJECTIVE

Middle cerebral artery (MCA) aneurysms are a particular subset of intracranial aneurysms that can be excluded by clipping or coiling. A comparison of the results between these two methods is often limited by a selection bias in which wide-neck and large aneurysms are frequently treated with surgery. Here, the authors report the results of two centers using opposing policies in the management of MCA aneurysms: one center used a clip-first policy while the other used a coil-first policy, which limited the selection bias and ensured a good comparison of these two treatment modalities.

METHODS

All patients treated for either ruptured or unruptured MCA aneurysms at one of two institutions between January 2012 and December 2015 were eligible for inclusion in this study. At one center a clip-first policy was applied, whereas the other applied a coil-first policy. The authors retrospectively reviewed the medical records of these patients and compared their clinical and radiological outcomes.

RESULTS

A total of 187 aneurysms were treated during the inclusion period; 88 aneurysms were treated by coiling and 99 aneurysms by clipping. The baseline patient and radiological characteristics were similar between the two groups, but the clinical presentation of the ruptured aneurysm cohort differed slightly. In the ruptured cohort (n = 90), although patients in the coiling group had a higher rate of additional surgery, the complication rate, functional outcome, and risk of death were similar between the two treatment groups. In the unruptured cohort (n = 97), the complication rate, functional outcome, and risk of death were also similar between the two treatment groups, although the risk of discomfort related to the temporal muscle atrophy was higher in the surgical group. Overall, the rate of complete occlusion was higher in the clipping group (84.2%) than in the coiling group (31%), which led to a higher risk in the coiling group of aneurysm retreatment within the first 2 years (p = 0.04).

CONCLUSIONS

Clipping and coiling for MCA aneurysm treatment provide the same clinical outcome for ruptured and unruptured aneurysms. However, clipping provides higher short- and long-term rates of complete exclusion, which in turn decreases the risk of aneurysm retreatment. Whether this lower occlusion rate can have a clinical impact in the long-term must be further evaluated.

Outcome and Prognostic Factors of Ruptured Middle Cerebral Artery Aneurysms Treated via Endovascular Approach: A Single-Center 11-Year Experience

OBJECTIVE

To investigate outcomes and prognostic factors of ruptured middle cerebral artery (MCA) aneurysms, treated via endovascular approach, with improving treatment materials and techniques.

PATIENTS AND METHODS

A total of 185 consecutive patients, admitted with acutely ruptured MCA aneurysms and treated by endovascular methods between 2006 and 2016, were retrospectively reviewed. Their baseline characteristics, procedure-related complications, and angiographic and clinical outcomes were collected. Univariate analysis and logistic regression analysis were completed to identify any association between procedure-related complications or clinical outcomes and potential risk factors.

RESULTS

Procedure-related complications occurred in 28 patients (15.1%), including aneurysm rebleeding in 7 (3.8%), hematoma expansion in 10 (5.4%), and ischemia in 13 (7.0%) (concurrent hemorrhage and ischemia in 2 patients), which resulted in morbidity/mortality of 7% and 1.4%. Final evaluations indicated that 153 patients (82.7%, 153/185) had a good outcome (modified Rankin Scale score 0-2). Among 120 (69.4%) who underwent angiographic follow-up, 89 (74.2%) were completely occluded and 20/120 (16.7%) were recanalized. Multivariate analysis of clinical outcome indicated that a high preoperative Hunt and Hess grade (IV-V), intrasylvian/intracerebral hematoma, and early period treatment (2006-2013) were associated with unfavorable outcomes.

CONCLUSIONS

Endovascular treatment for patients with ruptured middle cerebral artery aneurysms may offer favorable clinical and angiographic outcomes. With the evolution of treatment materials and updated techniques, treatment complications have become less common than previously reported in literature, and clinical outcomes have been improved in recent years.

Endovascular Treatment of Unruptured MCA Bifurcation Aneurysms Regardless of Aneurysm Morphology: Short- and Long-Term Follow-Up

BACKGROUND AND PURPOSE

The optimal treatment of unruptured middle cerebral aneurysms is still under debate. Although today almost any aneurysm can be treated endovascularly, there is a lack of data comparing endovascular and microsurgical repair of MCA aneurysms. The aim of our analysis is to provide data on the efficacy, clinical outcome, complications and re-treatment rates of endovascular treatment of this subtype of aneurysms.

MATERIALS AND METHODS

Between May 2008 and July 2017, endovascular treatment of 1184 aneurysms in 827 patients was performed in our department. Twenty-four percent of these aneurysms were located at the MCA, and 150 unruptured MCA bifurcation aneurysms treated with coiling, stent-assisted-coiling, or endovascular flow diverter (WEB device) were identified for this retrospective data analysis. Ninety-six percent of all aneurysms, ruptured and unruptured, were treated by an endovascular approach, which yields a low selection bias for aneurysms suitable for endovascular treatment. Follow-up examinations were performed after 12 and 36 months and then every 1-3 years after embolization. Procedures were analyzed for periprocedural complications, outcome, and retreatment rate of the WEB (n = 38) and coiling with (n = 45) or without stent assistance (n = 67).

RESULTS

The procedure-associated good clinical outcome (mRS ≦ 2) was 89.9%, and the mortality rate was 2.7%. Short-term follow-up good clinical outcome/mortality rates were 91.3%/0.7%. At discharge, 137 patients had an mRS of 0-2 (91.3%) and 13 had an mRS of 3-6 (8.7%). The retreatment rate was significantly higher in the WEB group (21.1%) compared with the coiling group with (5.9%) or without (2.2%) stent placement (P < .05).

CONCLUSIONS

Regardless of the architecture of MCA bifurcation aneurysms, the endovascular treatment can be performed with low morbidity/mortality rates. The higher retreatment rate in the WEB group correlates with the learning curve in choosing the right device size.

Outcomes of Retreatment for Intracranial Aneurysms — A Meta-Analysis

BACKGROUND

Long-term results from the International Subarachnoid Hemorrhage Trial (ISAT) and Barrow Ruptured Aneurysm Trial (BRAT) indicate considerably higher retreatment rates for aneurysms treated with coiling compared to clipping, but do not report the outcome of retreatment.

OBJECTIVE

To evaluate retreatment related outcomes.

METHODS

A meta-analysis in accordance with PRISMA guidelines was conducted using Medline search engines PubMed and EMBASE to identify articles describing outcomes after retreatment for intracranial aneurysms. Pooled prevalence rates for complete occlusion rate and mortality were calculated. Outcomes of different treatment and retreatment combinations were not compared because of indication bias.

RESULTS

Twenty-five articles that met the inclusion criteria were included in the meta-analysis. Surgery after coiling had a pooled complete occlusion rate of 91.2% (95% confidence interval [CI]: 87.0-94.1) and a pooled mortality rate of 5.6% (95% CI: 3.7-8.3). Coiling after coiling had a pooled complete occlusion rate of 51.3% (95% CI: 22.1-78.0) and a pooled mortality rate of 0.8% (95% CI: 0.15-3.7). Surgery after surgery did not provide a pooled estimate for complete occlusion as only one study was identified but had a pooled mortality rate of 5.9% (95% CI: 3.1-11.2). Coiling after surgery had a pooled complete occlusion rate of 56.1% (95% CI: 11.4-92.7) and a pooled mortality rate of 9.3% (95% CI: 4.1-19.9). All pooled incidence rates were produced using random-effect models.

CONCLUSION

Surgical retreatment was associated with a high complete occlusion rate but considerable mortality. Conversely, endovascular retreatment was associated with low mortality but also a low complete occlusion rate.

Risk factors for the recurrence of an intracranial saccular aneurysm following endovascular treatment

Background

This study was aimed to determine risk factors for the recurrence of an intracranial saccular aneurysm (ISA) following endovascular treatment. The findings will help medical professionals to identify patients having a high risk of ISA recurrence and assist them in developing appropriate follow-up plans.

Results

During the follow-up period, 12.6% of the patients (83/658) experienced recurrent ISAs. An analysis of related factors, including gender, age, hypertension, diabetes mellitus, smoking, tumor size, width of the aneurysm neck, the presence or absence of a rupture, the volume embolization ratio (VER), the application or nonapplication of a stent, and follow-up time, revealed that a tumor size > 10 mm in diameter, wide-necked aneurysms, an anterior communicating or middle cerebral artery aneurysm, an aneurysm rupture, a VER < 20%, the absence of stent assistance, and follow-up time were high-risk factors for the recurrence of ISAs.

Materials and Methods

We retrospectively reviewed the records of 658 patients who underwent endovascular treatment for ISAs from January 2010 through December 2014. Multivariable logistic regression was performed on the candidates’ risk factors, which were identified via univariable screening analysis.

Conclusions

Smoking, a large tumor size, a wide-necked aneurysm, an anterior communicating or middle cerebral artery aneurysm, an aneurysm rupture, a VER < 20%, and an absence of stent assistance are significant risk factors for the postoperative recurrence of an aneurysm. Strict follow-up plans should be created for ISA patients having these high-risk factors.

Risk factors for angiographic recurrence after treatment of unruptured intracranial aneurysms: Outcomes from a series of 178 unruptured aneurysms treated by regular coiling or surgery

BACKGROUND

Long-term stability after intracranial aneurysm exclusion by coiling is still a matter of debate; after surgical clipping little is known.

OBJECTIVE

To study outcome after endovascular and surgical treatments for unruptured intracranial aneurysms in terms of short- and long-term angiographic exclusion and risk factors for recanalization.

METHODS

From 2004 and 2009, patients treated for unruptured berry intracranial aneurysms by coiling or clipping were reviewed. Aneurysmal exclusion was evaluated using the Roy-Raymond grading scale; immediate clinical outcome was also assessed. Clinical outcome, recanalization, risk factors for recurrence and bleeding during the follow-up period were analyzed by groups; "surgery" and "embolization".

RESULTS

From 2004 to 2009, 178 consecutive unruptured aneurysms were treated. The post-procedure angiographic results for "surgery" were: total exclusion 75.6%; residual neck 13.5%; residual aneurysm 10.8%. For "embolization", the results were, respectively: 72%; 20.7%; and 7.2%. Morbidity was 3% for "surgery" and 1.6% for "embolization" (P=0.74); mortality was nil. Mean clinical and angiographic follow-up was 5years. Recurrence rate was of 11.5% for "surgery" vs. 44% for "embolization" with a mean follow-up of 4 and 5.75years, respectively (P=1.10-5). The retreatment rate was 8.4%. Two significant risk factors for recanalization were identified: maximum diameter of the aneurysm sac (P=0.0038) and pericallosal location (P=0.0388). No bleeding event occurred.

CONCLUSION

Both techniques are safe. The rate of aneurismal recurrence was significantly higher for embolization, especially for large diameter aneurysms and pericallosal locations. No bleeding event occurred after recanalization.

Endovascular treatment of previously clipped aneurysms: continued evolution of hybrid neurosurgery

Background/objective

The optimal management of residual or recurrent clipped aneurysms is infrequently addressed in the literature.

Methods

We reviewed our endovascular database from January 1998 to May 2016 to identify patients with clipped aneurysms undergoing subsequent endovascular treatment, evaluating treatment approach, and clinical and angiographic outcomes.

Results

60 patients underwent endovascular treatment of residual/recurrent clipped aneurysms; 7 rebled prior to endovascular therapy. Treatment was via coiling alone (n=25, 42%), stent assisted coiling (n=15, 25%), balloon assisted coiling (n=8, 13%), flow diversion (n=8, 13%), stenting alone (n=3, 5%), or flow diversion with coiling (n=1, 2%). The procedural permanent neurological morbidity and mortality rates were 3% and 2%, respectively. Over a clinical follow-up of 253.4 patient years (median 3.9 years), there was one rebleed in a patient who had declined further treatment. For 43 patients with at least 1 month of digital subtraction angiographic follow-up (median 3.4 years), complete aneurysm occlusion was seen in 79% of cases. Neck remnants were observed in 14%, and stable small dome remnants were observed in 7% of cases. In a subgroup of 18 patients with ‘clip induced’ narrow neck aneurysms, all domes were initially coil occluded (Raymond 1 or 2); there was no permanent procedural morbidity and no aneurysms required retreatment or recanalized over a median follow-up of 3.9 years.

Conclusions

Endovascular treatment of residual or recurrent clipped aneurysms is an excellent treatment approach in well selected patients; ‘clip induced’ narrow neck aneurysms fare particularly well after treatment both angiographically and clinically.

Treatment of unruptured intracranial aneurysms: a review

INTRODUCTION

Unruptured brain aneurysms (UIAs) present a challenge due to the lack of definitive understanding of their natural history and treatment outcomes. As the treatment of UIAs is aimed at preventing the possibility of rupture, the immediate risk of treatment must be weighed against the risk of rupture in the future. As such, treatment for a large proportion of UIAs is currently individualized.

AREAS COVERED

In this article, we discuss the important natural history studies of UIAs and discuss the existing scientific evidence and recent advances that help identify the rupture risk guide management of UIAs. We also address the recent advances in pharmacological therapy of UIAs. Expert commentary: In the recent years, there have been great advances in understanding the pathophysiology of UIAs and determining the rupture risk going beyond the traditional parameter of aneurysm size. Aneurysm morphology and hemodynamics play a pivotal role in growth and rupture. A true randomized trial for the management of UIAs is the need of the hour.

Large Residual Volume, Not Low Packing Density, Is the Most Influential Risk Factor for Recanalization after Coil Embolization of Cerebral Aneurysms

Background

Tight coil packing with density of at least 20%–25% is known to be important for preventing recanalization after embolization of cerebral aneurysms. However, large aneurysms sometimes recanalize regardless of the packing density, suggesting that the absolute residual volume which is determined by aneurysm volume and packing density may be more important risk factor for recanalization. To validate this hypothesis, we analyzed the factors affecting the outcomes of treated aneurysms at our institute.

Methods and Findings

We included 355 small and large aneurysms. The following six factors were obtained from every case: aneurysm volume (mL), neck size (mm), packing density (%), residual volume (mL), rupture status at presentation, and stent assistance (with or without stent). The data were then subjected to multivariate logistic regression analysis to identify significant risk factors for recanalization. Recanalization occurred in 61 aneurysms (17.2%). Significant predictors for recanalization were aneurysm volume (odds ratio, 15.3; P < 0.001) and residual volume (odds ratio, 30.9; P < 0.001), but not packing density (odds ratio, 0.98; P = 0.341). These results showed that for each 0.1-mL increase in aneurysm volume and residual volume, the risk of recanalization increased by 1.3 times and 1.4 times, respectively.

Conclusions

The most influential risk factor for recanalization after coil embolization was residual volume, not packing density. The larger the aneurysm volume, the greater the packing density has to be to minimize the residual volume and risk of recanalization. Since tight coil packing has already been aimed, further innovation of coil property or embolization technique may be needed. Otherwise, different treatment modality such as flow diverter or parent artery occlusion may have to be considered.

Influencing factors of immediate angiographic results in intracranial aneurysms patients after endovascular treatment

The purpose of this study was to analyze influencing factors associated with immediate angiographic results in intracranial aneurysms patients after endovascular treatment (EVT), providing theoretical evidence and guidance for clinical treatment of intracranial aneurysms. Totally 529 patients met the inclusive criteria, consisting of 338 males and 191 females. Gender; age; history of hypertension, diabetes, and smoking; intracranial atherosclerosis; rupture status, size and location, features of aneurysmal neck, shapes; vasospasm; treatment modality; and degree of aneurysm occlusion were all carefully and completely recorded. All data were investigated in univariate and multivariate logistic regression model to determine whether they were correlated with the degree of aneurysm occlusion. According to aneurysm size, aneurysms were classified as micro-miniature, miniature, and large aneurysms. There were 451 narrow-neck aneurysms and 78 wide-neck aneurysms. Totally 417 were regular and 112 were irregular. And 125 were un-ruptured aneurysms; 404 were ruptured aneurysms. The modalities of treatment were as follows: embolization with coil (n = 415), stent-assisted coil embolization (n = 89), and balloon-assisted coil embolization (n = 25). Univariate analysis showed that aneurysm size, feature of aneurysm neck, shape, and rupture status might affect the immediate occlusion after EVT. Multivariate logistic regression analysis indicated that ruptured aneurysm, tiny aneurysm, and wide-neck aneurysm were independent influencing factors of complete occlusion of intracranial aneurysm. Aneurysm rupture status, size, feature of aneurysmal neck, and shape might be the independent influencing factors of immediate angiographic results in intracranial aneurysm patients after EVT. Un-ruptured, micro-miniature, narrow-neck, and regular-shaped aneurysms were more probable to be occluded completely.

Predictors of success following endovascular retreatment of intracranial aneurysms

INTRODUCTION

Although approximately one in every 10 patients undergoing coil embolization of intracranial aneurysms requires retreatment, the factors that are associated with outcome following retreatment remain to be fully elucidated.

METHODS

This is a single-center, retrospective review of 43 patients with 58 intracranial aneurysms that were retreated from 2004 to 2014. Aneurysms undergoing first time or microsurgical retreatment were excluded. Retreatment types were grouped into those without permanent parent vessel support (stand-alone and balloon-assisted coiling) versus those with permanent parent vessel support (stent-assisted coiling, stand-alone stenting, and flow diversion). The Modified Raymond Roy Classification was used to group aneurysms at all angiographic follow-up points either in the successful outcome group (Class I or II) or the unsuccessful outcome group (Class IIIa or IIIb).

RESULTS

Of aneurysms with follow-up, 50% were in the successful group and 50% in the unsuccessful group. In univariate analysis, small aneurysm size (p < 0.001), previous treatment type (p = 0.022), retreatment type (p = 0.001), and initial occlusion class (p = 0.005) were all associated with angiographic outcome. In multivariate analysis, small aneurysm size (p = 0.005, odds ratio (OR) 24.56, confidence interval (CI) 2.68-225.4) and retreatment type with permanent parent vessel support, namely stent-assisted coiling (p = 0.017, OR 31.1, CI 1.89-517.7), were associated with retreatment success.

CONCLUSIONS

Small aneurysm size and retreatment with permanent parent vessel support, namely stent-assisted coiling, are predictors of success following endovascular retreatment of intracranial aneurysms. These findings could be useful in the effort to both prevent and predict treatment failure following endovascular retreatment.