Endovascular treatment of ruptured blister-like aneurysms with special reference to the flow-diverting strategy

Endovascular treatment of small-parent artery aneurysms: mid-term results of the silk vista baby flow diverter

PURPOSE

We aim to retrospectively evaluate patients treated with SVB at our single center, assessing its efficacy, radiologic and clinical outcomes, and complication profile.

METHOD

This retrospective, single-center study included patients with small parent artery aneurysms treated with SVB. Patients were monitored for procedural success, aneurysm occlusion, and complications, with radiologic and clinical follow-up conducted.

RESULTS

The study included 64 patients with 66 small parent artery aneurysms treated using SVB FDs. Among these patients, 26 (40.6%) presented with subarachnoid hemorrhage (SAH). The mean index aneurysm size was 5.7 ± 5.25 mm. The cohort consisted of 15 males (23.4%) and 49 females (76.6%), with a mean age of 54.23 ± 14.95 years (range: 5-80 years). SVB was used as a standalone treatment in 42 patients (65.6%), while adjunctive materials were applied in 22 cases (34.4%)-coils in 16 (24.2%) and a regular stent in 6 (9.1%). A total of 71 SVB stents were deployed for 66 aneurysms, achieving a 100% technical success rate. In 30 patients with multiple aneurysms, additional aneurysms were addressed during the same session along with the index aneurysm. The mean duration of clinical and radiological follow-up was 10.5 ± 7.94 months. Among a total of 7 patients (10.9%) with ischemic complications, 3 (4.7%) were related to SVB implantation. Index aneurysm occlusion was accomplished in 93.3% of cases at the last follow-up. Favorable neurological outcomes (mRS 0-2) were recorded in 53 patients (82.8%). Subgroup analysis showed that 6 out of 7 total complications (85.7%) occurred in patients with multiple aneurysms.

CONCLUSION

The SVB FDs are a highly effective and safe treatment option for distal intracranial aneurysms, achieving high occlusion rates with a favorable safety profile.

Endovascular treatment of intracranial blood blister-like aneurysms with the Willis covered stent: a case series

BACKGROUND AND PURPOSE

To evaluate the safety, feasibility, and effectiveness of the Willis covered stent (WCS) in treating blood blister-like aneurysms (BBAs).

MATERIALS AND METHODS

Twenty-one consecutive patients with BBAs treated with the WCS were identified between July 2017 and July 2022. The demographic, clinical, and angiographic data and procedural-related complications were collected from the medical records and the operative reports.

RESULTS

The present study included six men and fifteen women, with a mean age of 51.6 years (31-70 years). The immediate postoperative angiography demonstrated that the complete occlusion rate was 100%, with no endoleak. Ophthalmic artery (OA) occlusion occurred in five patients (23.8%). One patient developed delayed stent thrombosis on the third postoperative day. The mean angiographic follow-up time was 9.2 months (range 3-21 months). All twenty-one BBAs were occluded entirely, and the patency of the parent arteries was preserved. No aneurysm rupture or recurrence was found, and no retreatment was needed. Two patients developed mild to moderate asymptomatic in-stent stenosis. The clinical follow-up time was 20.0 months (range 15-33 months). Twenty patients had an mRS score of zero, and one had an mRS score of one.

CONCLUSIONS

Our series indicates that treating BBAs with WCSs was relatively safe and efficacious. However, the incidence of stent delivery failure and complications should not be neglected.

Comparative analysis of characteristics, management, and clinical outcome of blood blister-like aneurysms treated with flow diverter devices: a systematic review and meta-analysis of 30 studies

BACKGROUND AND AIM

Because of relatively little data for blood blister-like aneurysms (BBAs) treated with flow diverter (FD) devices, existing studies failed to provide comprehensive analysis for the characteristics, management, and clinical outcome of the disease. Therefore, the authors collected and analyzed current evidence aiming to provide quantitatively pooled results for the management, complication, clinical, and angiographic outcomes as well as the risk factors of prognosis of BBAs treated with FD devices.

METHODS

A systematic search of PubMed, Cochrane Library, and Web of Science up to 1 May 2024 was conducted for relevant studies. The primary outcomes were to expound the management, characteristics, and clinical outcomes of BBAs treated with FD devices. The secondary outcomes were to determine the difference of characteristics and outcomes, as well as the risk factors of BBAs treated with FD devices. Two reviewers assessed trial quality and extracted the data independently. All statistical analyses were performed using the standard statistical procedures provided in Review Manager 5.2 and Stata 12.0.

RESULTS

A total of 30 reports with 311 of 783 BBA patients were identified. The pooled results indicated that 76.3% BBAs were located in the internal carotid artery (ICA), and 85 and 84% patients experienced complete occlusion and a modified Rankin scale (mRS) score 0-2, respectively, at follow-up time. Female BBAs patients (69.9%) were more prevalent and 88.5% patients experienced a favorable outcome at discharge. The overall and periprocedural complications account for 16.8 and 9.1%, respectively. The pooled results showed that the incidence of complete occlusion was 50% (95% CI: 31-69%), 80% (95% CI: 67-92%), and 84% (95% CI: 77-91%) at immediate, short, and long-term angiographic results, respectively. In addition, the favorable, moderate, and poor clinical outcomes evaluated with mRS were 89% (95% CI: 85-94%), 13% (95% CI: 5-21%), and 8% (95% CI: 3-13%), respectively. The authors found that compared to moderate or poor outcomes, patients with good outcomes experienced significantly lower preoperative scores (MD -1.24; 95% CI: -1.94 to -0.53), more complete occlusion (OR 5.17; 95% CI: 1.26-21.15) and less complications (OR 0.20; 95% CI: 0.08-0.47), respectively. It was observed that patients who experienced a complication had a higher onset Hunt-Hess scale (MD 0.49; 95% CI: 0.03-0.96) and Fisher's score (MD 1.43; 95% CI: 0.72-2.13), respectively. Patients with good outcomes experienced younger age (MD -5.76 years; 95% CI: -11.31 to -0.21) and lower onset Hunt-Hess scale (MD -0.96; 95% CI: -1.45 to -0.47), respectively.

CONCLUSIONS

BBA was middle-aged female predominant and common in ICA. The majority of patients generally experienced favorable outcomes with a low incidence of periprocedural complications. In addition, good outcomes benefited from lower preoperative scores, more complete occlusion, less complications, and younger age. Higher onset Hunt-Hess scale and Fisher's score may increase the risk of complications. Future studies with enough sample size and long follow-up are required to clear the management, long-term outcomes, and risk factors of BBAs.

Flow diverting stent monotherapy as the best choice in the treatment of intracranial blood blister-like aneurysms: a systematic review

OBJECTIVE

To evaluate the effectiveness and safety of flow-diverting stent (FDS) monotherapy in the treatment of intracranial blood blister-like aneurysms (BBAs) through a detailed systematic review.

METHODS

This review adheres to the PRISMA guidelines, focusing on studies utilizing FDS monotherapy for BBAs, spanning from July 2010 to November 2023. A systematic search across databases including Embase, Medline/PubMed, Scopus, and Google Scholar was conducted. Studies in English that solely used FDS for BBA treatment and assessed perioperative complications were included. Data from 23 studies encompassing 181 cases were systematically analyzed for patient demographics, aneurysm characteristics, treatment specifics, and outcomes.

RESULTS

The collected data indicates a dominant occurrence of BBAs in the internal carotid artery (86.9%), with a mean patient age of 50.27 years and a higher prevalence in females (73.43%). Treatment timing varied, with 45.9% treated within the first three days, 35.7% were treated between 4 and 14 days, and 18.4% of patients were treated after 14 days. The study found a complete occlusion rate of 88.1% in follow-up imaging and a favorable clinical outcome in 82.2% of cases. Periprocedural complications were reported in 19.2% of patients, with a related mortality rate of 3.9%.

CONCLUSIONS

The systematic review demonstrates that FDS monotherapy is highly effective and safe in the treatment of intracranial BBAs. It offers a high rate of complete aneurysm occlusion, favorable clinical outcomes, and low complication rates. These results highlight FDS monotherapy as a prominent treatment method, ensuring robust aneurysmal protection while maintaining the patency of the parent artery.

Treatment with a flow diverter-assisted coil embolization for ruptured blood blister-like aneurysms of the internal carotid artery: a technical note and analysis of single-center experience with pooled data

Treatment of blood blister-like aneurysms (BBAs) of the supraclinoid internal carotid artery (ICA) with flow diverters (FDs) has become widespread in recent years. However, ruptured blood blister-like aneurysm (BBA) of ICA treatment with flow diverter-assisted coil embolization (FDAC) remains controversial. Moreover, limited direct comparative studies have been conducted between the two treatment modalities, FDs and FDAC, for BBAs. The purpose of this study was to document our experience and evaluate the effectiveness and safety of FDAC. We conducted a retrospective analysis of clinical and radiological information from ten patients who experienced ruptured BBAs of the supraclinoid ICA at our center from January 2021 to February 2023. The technical details of FDAC for ruptured BBAs were described, and the technical steps were named "pipeline embolization device (PED)-Individualized shaping(microcatheter)-Semi deploying-Rivet(coils)-Massage(microwire)" as the PEISSERM technique. Clinical outcomes were assessed using the modified Rankin Scale (mRS), whereas radiological results were determined through angiography. A pooled analysis was implemented, incorporating data from literature sources that reported perioperative and long-term clinical and angiographic outcomes of ruptured BBAs treated with FD and FDAC strategies, along with our data. Data in our analysis pool were categorized into FD and FDAC strategy groups to explore the preferred treatment modalities for BBAs. The PEISSERM technique was utilized to treat ten patients, seven males, and three females, with an average age of 41.7 years. A single PED was deployed in conjunction with coils in all ten patients. All PEDs were documented to have good wall apposition. The immediate postoperative angiograms demonstrated Raymond grade I in ten aneurysms. Angiographic follow-up of nine patients at 4-25 months showed total occlusion of the aneurysms. At the most recent follow-up, the mRS scores of nine patients hinted at a good prognosis. Pooled analysis of 233 ICA-BBA cases of FD revealed a technical success rate of 91% [95% confidence interval (CI), 0.88 to 0.95], a rate of complete occlusion of 79% (95% CI, 0.73 to 0.84), a recurrence rate of 2% (95% CI, 0.00 to 0.04), a rebleed rate of 2% (95% CI, 0.00 to 0.04), and the perioperative stroke rate was 8% (95% CI, 0.04 to 0.11). The perioperative mortality was 4% (95% CI, 0.01 to 0.07). The long-term good clinical outcome rate was 85% (95% CI, 0.80 to 0.90). The mortality rate was 6% (95% CI, 0.03 to 0.09). Results from the subgroup analysis illustrated that the FDAC strategy for BBAs had a significantly higher immediate postoperative complete occlusion rate (P < 0.001), total occlusion rate (P = 0.016), and a good outcome rate (P = 0.041) compared with the FD strategy. The FDAC strategy can yield a higher rate of good outcomes than the FD strategy. The PEISSERM technique employed by the FDAC is a reliable and effective treatment approach as it can minimize the hemodynamic burden of BBA's fragile dome, thereby achieving an excellent occlusion rate. The PEISSERM technique in the FDAC strategy contributes to understanding the BBA's treatment and offers a potentially optimal treatment for BBA.

Perioperative and long-term complications following therapeutic internal carotid artery occlusion

BACKGROUND

Parent artery occlusion (PAO) is an effective treatment for hemorrhagic diseases associated with the internal carotid artery. There are several reports of long-term cerebral infarction or the formation of de novo cerebral aneurysms following PAO.

MATERIALS AND METHODS

We retrospectively reviewed these complications in 38 patients who underwent PAO for therapeutic treatment. We investigated perioperative cerebral infarctions, long-term cerebral infarctions, and de novo aneurysms.

RESULTS

The mean age of the patients was 64.0 years, and 25 patients (65.8%) were female. The causative diseases were unruptured (n = 19; 50.0%) and ruptured (n = 8; 21.1%) aneurysms. PAO was performed after ischemic tolerance was assessed with balloon test occlusion (BTO), and BTO was performed in 34 patients, of whom 25 (73.5%) had ischemic tolerance. Twenty-six patients (68.4%) were treated with PAO alone, eight (23.5%) with low-flow bypass, and six (17.6%) with high-flow bypass. Perioperative complications occurred in five patients (13.2%): two of the 26 patients (7.7%) who underwent scheduled treatment and three of the 12 patients (25.0%) who underwent emergency treatment. One patient (2.6%) had long-term de novo aneurysm, and none developed cerebral infarction.

CONCLUSIONS

These results showed that the assessment of ischemic tolerance by performing BTO and appropriate revascularization in scheduled treatments are important to reduce perioperative and long-term cerebral infarctions. PAO must be performed with greater caution in emergency treatment.

Flow Diverter Device-Assisted Coiling Treatment for Cerebral Blister Aneurysm: A Single-Center Study

Although endovascular treatment is a promising approach, blood blister-like aneurysms (BBAs) still present treatment challenges. This study aimed to assess the effectiveness and safety of flow diverter device-assisted coiling (FDDAC) for the treatment of BBAs, which are broad based and friable with a high rebleeding risk. Eight patients (five females and three males) who presented with subarachnoid hemorrhages (SAH) due to BBA ruptures between May 2020 and May 2022 were retrospectively enrolled. All patients were treated by flow diverter device (Tubridge) adjunctive coil embolization using a semi-deploying technique. The demographic information, angiographic data, interval between admission and treatment, materials, therapy, clinical outcomes (including periprocedural and intraprocedural mortality and morbidity), and follow-up results of all patients were reviewed. The mean age of the patients with BBAs was 48.5 years (range 31–62 years); aneurysm sizes ranged from 2.2 × 1.7 mm to 4.6 × 3.2 mm, and the median Hunt–Hess score was 3. All aneurysms were completely closed at follow-up, and all 8 patients had excellent clinical outcomes (modified Rankin scores = 0–2) at discharge. Angiograms showed complete aneurysm occlusion after 6 months to 1 year. In addition, there were no cases of re-rupture, re-treatment, or recurrence of the aneurysms. FDDAC is safe to use in patients with BBAs and provides an alternative treatment option for this disease.

Retreatment with a flow diverter for recurrent blood blister-like aneurysms after embolization: A single-center case series

Background and purpose

Treatment of blood blister-like aneurysms (BBAs) has been a significant challenge mainly due to their high recurrence rate even after stent-assisted coiling (SAC) embolization. This study aims to evaluate the safety and efficacy of treating recurrent BBAs after SAC with a flow diverter (FD).

Methods

A retrospective series of patients with recurrent BBAs who underwent the retreatment with the FD from June 2018 to December 2021 was included to analyze perioperative safety and immediate postoperative and follow-up outcomes.

Results

The study enrolled 13 patients with recurrent BBAs previously treated with SAC. Within previous stents, an FD was deployed for retreatment, including eight Tubridge FDs and five PEDs. The time interval between initial treatment and FD implantation was 14–90 days. A total of 11 cases were treated with a single FD alone; two cases were treated with further endovascular coiling embolization, followed by FD implantation. The angiographic follow-up (6–12 months) was available in 12 patients, and all 12 recurrent BBAs were completely occluded. No perioperative complication was detected, and no rebleeding was found during the clinical follow-up (6–36 months).

Conclusion

The use of the FD to manage recurrent BBAs after SAC is technically feasible, safe, and effective. The key to the success of the procedure is to ensure that the FD stent is fully open and has good apposition with the previously implanted stent.

Application of the Willis covered stent in the treatment of internal carotid artery blood blister-like aneurysms

The optimal treatment for blood blister-like aneurysm (BBA) has not yet been determined, and BBA has a high recurrence rate after stent-assisted embolization. The purpose of the present study was to evaluate the safety and feasibility of patients with BBA rupture in the acute phase or patients with BBA who have recurrence after stent-assisted coil embolization. Eight patients (8 women, mean age 50.3 ± 3.7 years) who presented with ruptured BBA or recurrence BBA that had been treated by stent-assisted embolization (5 patients after primary treatment of stent-assisted embolization) were retrospectively reviewed. Clinical follow-up was performed at 1 year after endovascular treatment. All patients were successfully treated with the WCS, and immediate postoperative angiography showed that the aneurysms were completely isolated. The ophthalmic artery was covered by WCS in one patient; however, this patient did not show any clinical visual field or vision symptoms. Procedure-related complications such as aneurysm rupture, vasospasm, acute thrombosis, or thromboembolism did not occur in any case. All patients were followed up for 1 year after endovascular treatment, and they were in good condition without recurrence. One patient developed delayed bleeding at the right temporal lobe. All patients had good clinical prognosis (modified Rankin Scale score ≤ 2). WCS implantation may be a safe and feasible strategy for patients with BBA rupture in the acute phase and patients with BBA who have recurrence after stent-assisted coil embolization and is a promising option worth exploring.

Early Treatment of Ruptured Blood Blister-Like Aneurysms of the Internal Carotid Artery With Flow Diverters Using Single Antiplatelet Therapy: A Single-Center Experience With Long-Term Follow-Up

Background and Purpose: Blood Blister-like aneurysms (BBAs) of the internal carotid artery (ICA) are rare entities of cerebral aneurysms. FD use in acutely ruptured aneurysms, timing of treatment and antiplatelet regimen are main debate topics in clinical practice when the treatment decision is flow diversion. The aim of this study is to report the safety and efficacy of a single-center FD treatment for ruptured BBAs in the early phase of SAH using the SAPT regimen.

Material and Method: This study involved a retrospective analysis of a prospectively collected database. Records of patients admitted to our clinic and treated by endovascular route on ruptured BBA between January 2013 and December 2020 were reviewed. Ruptured supraclinoid ICA BBAs treated with FD devices with SAPT within 48 h from ictus of SAH are included. BBA of atypical anatomic locations, other endovascular techniques performed, and delayed admissions (>48 h) were excluded from the study. Demographic, clinical and angiographic features of patients and aneurysms, FD types and numbers, periprocedural complications, immediate and follow-up angiographic and clinical outcomes were recorded.

Results: A total of six patients with ruptured BBAs treated via FDs within 48 h and used SAPT were included in the study. The mean age was 41.6 years (range from 34 to 45 years), and four of six patients were female. All patients were treated within 48 h after ictus, and the mean treatment day was 1.33 days. One patient received ticagrelor, and five patients received prasugrel as SAPT for one year after treatment. No procedure-related death and rebleeding were recorded. One (16.7 %) treatment responsive procedure-related complication occurred (transient ischemia). Overall good outcome rate was 83.3%. One patient died due to pneumonia. The immediate control angiograms showed complete occlusions of BBAs in one patient (16.6%). The complete occlusion rate was 100 % for five survivors at the control angiogram. The median follow-up was 49.5 months.

Conclusion: This single-center experience suggests that early treatment (<2 days) within SAH of ruptured BBAs with FDs using SAPT is safe and effective in terms of clinical and radiological long-term outcomes.

Comparison of Blister Aneurysm Treatment Techniques: A Systematic Review and Meta-Analysis

OBJECTIVE

Blood blister aneurysms are small, thin-walled, rapidly growing side-wall aneurysms that have proved particularly difficult to treat, and evidence-based guidance for treatment strategies is lacking. A systematic review and meta-analysis was performed to aggregate the available data and compare the 3 primary treatment modalities.

METHODS

We performed a comprehensive literature search according to PRISMA guidelines followed by an indirect meta-analysis that compares the safety and efficacy of surgical, flow-diverting stents (FDS), and other endovascular approaches for the treatment of ruptured blood blister aneurysms.

RESULTS

A total of 102 studies were included for quantitative synthesis, with sample sizes of 687 treated surgically, 704 treated endovascularly without FDS, and 125 treated via flow diversion. Comparatively, FDS achieved significantly reduced rates of perioperative retreatment compared with both surgical (P = 0.025) and non-FDS endovascular (P < 0.001). The FDS subgroup also achieved a significantly lower incidence of perioperative rebleed (P < 0.001), perioperative hydrocephalus (P = 0.012), postoperative infarction (P = 0.002), postoperative hydrocephalus (P < 0.001), and postoperative vasospasm (P = 0.002) compared with those patients in the open surgical subgroup. Although no significant differences were found among groups on the basis of functional outcomes, angiographic outcomes detailed by rates of radiographic complete occlusion were highest for surgical (90.7%, 262/289) and FDS (89.1%, 98/110) subgroups versus the non-FDS endovascular subgroup (82.7%, 268/324).

CONCLUSIONS

Flow diversion seems to be an effective treatment strategy for ruptured blood blister aneurysms, with lower rates of perioperative complications compared with surgical and other endovascular techniques, but studies investigating long-term outcomes after flow diversion warrant further study.

Endoluminal flow diverters in the treatment of sidewall and bifurcation aneurysm: A systematic review and meta-analysis of complications and angiographic outcomes

BACKGROUND AND AIM

The use of endoluminal flow diversion in bifurcation aneurysms has been questioned due to the potential for complications and lower occlusion rates. In this study we assessed outcomes of endovascular treatment of intracranial sidewall and bifurcation aneurysms with flow diverters.

METHODS

In July 2020, a literature search for all studies utilizing endoluminal flow diverter treatment for sidewall or bifurcation aneurysms was performed. Data were collected from studies that met our inclusion/exclusion criteria by two independent reviewers and confirmed by a third reviewer. Using random-effects meta-analysis the target outcomes including overall complications (hematoma, ischemic events, minor ischemic stroke, aneurysm rupture, side vessel occlusion, stenosis, thrombosis, transient ischemic stroke, and other complications), perioperative complications, and follow-up (long-term) aneurysm occlusion were intestigated.

RESULTS

Overall, we included 35 studies with 1084 patients with 1208 aneurysms. Of these aneurysms, 654 (54.14%) and 554 (45.86%) were classified as sidewall and bifurcation aneurysm, respectively, based on aneurysm location. Sidewall aneurysms had a similar total complication rate (R) of 27.12% (95% CI, 16.56%-41.09%), compared with bifurcation aneurysms (R, 20.40%, 95% CI, 13.24%-30.08%) (p = 0.3527). Follow-up angiographic outcome showed comparable complete occlusion rates for sidewall aneurysms (R 69.49%; 95%CI, 62.41%-75.75%) and bifurcation aneurysms (R 73.99%; 95% CI, 65.05%-81.31%; p = 0.4328).

CONCLUSIONS

This meta-analysis of sidewall and bifurcation aneurysms treated with endoluminal flow diverters demonstrated no significant differences in complications or occlusion rates. These data provide new information that can be used as a benchmark for comparison with emerging devices for the treatment of bifurcation aneurysms.

Ruptured Intracranial Aneurysms Treated with the Pipeline Embolization Device: A Systematic Review and Pooled Analysis of Individual Patient Data

BACKGROUND

The Pipeline Embolization Device (PED) is a flow-diverting stent for the treatment of intracranial aneurysms and is used off-label for a subset of ruptured aneurysms not amenable to traditional treatment.

PURPOSE

Our aim was to evaluate the safety and efficacy of the PED for treatment of ruptured intracranial aneurysms.

DATA SOURCES

A systematic review of the MEDLINE, EMBASE, and Scopus data bases from January 2011 to March 2020 was performed for articles reporting treatment of ruptured intracranial aneurysms with the PED.

STUDY SELECTION

A total of 12 studies comprising 145 patients with 145 treated aneurysms were included for analysis.

DATA ANALYSIS

Individual patient data were collected. Nonparametric tests were used to compare differences among patients. Logistic regression was used to determine an association with outcome variables.

DATA SYNTHESIS

Mean aneurysm size was 5.9 mm, and most were blister (51.0%) or dissecting (26.9%) in morphology. Three (2.1%) aneurysms reruptured following PED placement. Univariate logistic regression identified larger aneurysm size as a significant predictor of aneurysm rerupture (P = .008). Of patients with radiographic follow-up, 87.5% had complete aneurysm occlusion. Symptomatic neurologic complications occurred in 16.5%.

LIMITATIONS

Analysis was limited by the quality of the included data, most of which were from small case series representing class III medical evidence. No study assessed outcome in a blinded or independently adjudicated manner.

CONCLUSIONS

Most ruptured aneurysms treated with the PED were blister or dissecting aneurysms. Treatment was associated with a rerupture rate of 2.1% and a complete occlusion rate of 87.5%.

Ruptured blood blister like aneurysm: does the best therapeutic option really exist?

Our study aimed to evaluate the outcome of patients with ruptured blood-blister like aneurysm (BBLA) in our institution by comparing microsurgical selective treatment to endovascular treatment using flow-diverter stent (FD). Our study included 18 consecutive patients treated for BBLA between 2004 and 2020. Until 2014, microsurgery was preferred in all patients with BBLA (n = 10). Significant postoperative morbi-mortality was recorded at this time and led us to change therapeutic strategy and to favor FD as first-line treatment in all patients (n = 8). Postprocedural complications and BBLA occlusion were recorded. High WFNS score (> 2) was noted in 6 patients of microsurgical group and in 2 of endovascular group. In microsurgical group, ischemic lesions were noted in 6 patients and led to death in 3 patients. Immediate BBLA occlusion was obtained in all patients. Favorable outcome after 3 months (mRS < 3) was recorded in 4 of the 7 survivors. In endovascular group, ischemic lesions were noted in 4 patients. One patient died from early postprocedural BBLA rebleeding. Scarpa hematoma was noted in 3 patients with surgical evacuation in 1. Persistent BBLA at 3 months was recorded in 4 patients without rebleeding, but further FD was required in 1 with growing BBLA. Favorable outcome was noted in 6 of the 7 survivors. Although, rate of morbi-mortality appear lower in patients treated with FD, neurological presentation was better and BBLA diagnosis remains questionable in this group. Moreover, persistent BBLA imaging with potential risk of rebleeding after FD deserves to be discussed.

Endovascular Treatment of Ruptured Intracranial Blister Aneurysms: A Systematic Review and Meta-analysis

BACKGROUND

Endovascular treatment of blister aneurysms is a promising approach, even though they are vascular lesions challenging to treat due to their angioarchitectural characteristics.

PURPOSE

Our aim was to investigate clinical and radiologic outcomes after endovascular treatment of ruptured blister aneurysms.

DATA SOURCES

PubMed, Ovid MEDLINE, Ovid EMBASE, Scopus, and the Web of Science were screened.

STUDY SELECTION

We performed a comprehensive review of the literature from 2010 to 2019 reporting series of patients with blister aneurysms treated with an endovascular approach.

DATA ANALYSIS

Event rates were pooled across studies using a random effects meta-analysis.

DATA SYNTHESIS

A total of 32 studies reporting on 684 patients (707 aneurysms) were included. Stent placement, stent-assisted coiling, and flow diversion were the most commonly described treatments (282, 256, and 155 patients, respectively). The long-term complete occlusion rate was 76.9% (95% CI, 69.2%-83.9%). The perioperative complication rate was 8.9%, and clinical outcome at final follow-up was mRS <2 in 76.6% (95% CI, 68.2%-84.2%) of patients. The mortality rate was 4.7% (95% CI, 2.30%-7.80%). Among the different techniques, stent-assisted coiling is the one that had the higher rate of immediate occlusion (63.4%); however, the occlusion rate at the final follow-up was comparable among the different techniques.

LIMITATIONS

Different techniques were described and data were reported in a nonhomogeneous way, possibly representing a bias in the present study.

CONCLUSIONS

This study suggests that endovascular treatment of blister aneurysms is associated with good long-term occlusion rates and reasonable complication and mortality rates. There is no consensus on the best endovascular techniques in blister aneurysm management.

Treatment of Ruptured Blister-Like Aneurysms with the FRED Flow Diverter: A Multicenter Experience

BACKGROUND AND PURPOSE

Treatment of ruptured blister-like aneurysms is technically challenging. This study aimed at analyzing the safety and efficacy of the Flow-Redirection Endoluminal Device (FRED) in the treatment of ruptured blister-like aneurysms.

MATERIALS AND METHODS

In a retrospective multicenter study, all patients treated with the FRED due to a ruptured intracranial blister-like aneurysm between January 2013 and May 2019 were analyzed. The primary end points for clinical safety were mRS 0-2 at 6 months after treatment and the absence of major ipsilateral stroke or death. The primary end points for efficacy were the absence of rebleeding after treatment and complete angiographic occlusion according to the O'Kelly-Marotta classification at 6 months after treatment.

RESULTS

In total, 30 patients with 30 ruptured blister-like aneurysms were treated. Immediate complete aneurysm obliteration (O'Kelly-Marotta classification D) with the FRED was achieved in 10 patients (33%). Of the 26 patients with follow-up, complete obliteration was achieved in 21 patients (80%) after 6 months and in 24 patients (92%) in the final follow-up (median, 22 months). Twenty-three patients (77%) achieved mRS 0-2 at 6 months. Major stroke or death occurred in 17%. Two patients died due to pneumonia, and 2 patients died due to infarction following cerebral vasospasm. There was no case of rebleeding after FRED implantation. There was 1 case of delayed asymptomatic stent occlusion.

CONCLUSIONS

Treatment of ruptured blister-like aneurysms with the FRED is safe and effective.

Flow diverting devices in acute ruptured blood blister aneurysms: a three centric retrospective study

BACKGROUND

Blood blister aneurysms (BBAs) are a rare tiny subset of intracranial aneurysms, located at the nonbranching site of an artery, representing a therapeutic challenge from both surgical and endovascular approach. Flow-diverting efficacy, by preserving flow through the parent artery, was approved for its use in unruptured cerebral aneurysms, but no consensus was reached on its use for BBAs ruptured in the acute setting. We report a multicenter experience of use of flow diversion in acute setting of ruptured BBA, to analyze the safety and efficacy of these devices.

METHODS

We performed a retrospective study of 6 consecutive intracranial BBAs treated with flow diverter devices (FDD) between 2018 and 2020 at 3 italian institutions. Materials, therapy used, complications, clinical and radiographic outcomes were reviewed.

RESULTS

We used different FDD, in all cases immediate change in contrast opacification at the end of the procedure was reported. Intraprocedural IIb/IIIa inhibitor agent was the major antiplatelet protocol administered. Any complications occurred. All patients showed complete BBA obliteration at 3 months follow-up. 5/6 patients achieved good clinical outcome (0-2 mRS) at 3 months, all of which were presented with low grade SAH (Hunt Hess I-III) and a lower Fisher grade.

CONCLUSION

Our data support this endovascular technique as a safe and effective therapeutic modality for this pathology in the acute setting.

Comparison of Bypass and Non-Bypass Surgical Treatments for Internal Carotid Artery Blood Blister-Like Aneurysms: A Meta-Analysis of Efficacy, Safety, and Outcomes

BACKGROUND

The optimal surgical strategy for treating internal carotid artery (ICA) blood blister-like aneurysms (BBAs) has remained unclear. Although some have preferred bypass surgery, others have favored less-demanding surgical methods. The aim of the present meta-analysis was to assess the efficacy, safety, and outcomes of bypass and non-bypass surgical methods when intended as primary treatment of ICA BBAs.

METHODS

Studies reporting data on the outcomes of interest for surgically treated patients with ICA BBAs were searched for in the PubMed/MEDLINE, Evidence-Based Medicine Reviews, Cochrane Central, ProQuest, and Scopus databases. The data were analyzed using random effects modeling.

RESULTS

Seven observational studies involving 140 patients met the inclusion criteria. The patients treated with bypass surgery, compared with those treated with non-bypass techniques, had lower odds of poor outcomes (odds ratio [OR], 0.75; 95% confidence interval [CI], 0.28-2.02; P = 0.57; I² = 0%), postoperative vasospasm (OR, 1.73; 95% CI, 0.38-7.92; P = 0.48; I² = 19%), intraoperative bleeding (OR, 3.37; 95% CI, 0.82-13.90; P = 0.09; I² = 0%), postoperative bleeding (OR, 1.91; 95% CI, 0.47-7.76; P = 0.36; I² = 0%), and postoperative recurrence of BBAs (OR, 2.16; 95% CI, 0.54-8.66; P < 0.28; I² = 0%). No comparison, however, achieved statistical significance.

CONCLUSIONS

For surgeons who use both bypass and non-bypass surgical strategies, the 2 methods seemed comparable in terms of the outcomes of interest, although the bypass technique appeared superior. However, comparisons with studies reporting bypass as the uniquely preferred technique have indicated that specialization in, and preference for, the bypass procedure has been associated with more favorable outcomes.

Ruptured Fisher grade 3 blister aneurysms have a higher incidence of delayed cerebral ischemia than ruptured Fisher grade 3 saccular aneurysms

BACKGROUND

Blister aneurysms are a rare subclass of aneurysms, which remain challenging to treat both with open cerebrovascular and endovascular techniques, and clinicians continue to see poor outcomes in some cases despite improvements in technology. Based on our clinical observations, we hypothesized that patients with a Fisher grade 3 subarachnoid hemorrhage (SAH) from a ruptured anterior circulation blister aneurysm are significantly more likely to develop poor outcome due to delayed cerebral ischemia than patients with a Fisher grade 3 SAH from a ruptured anterior circulation saccular aneurysm.

METHODS

In this consecutive case series, we reviewed management, outcomes, and rates of delayed cerebral ischemia for all ruptured anterior circulation blister aneurysms from 2012 to 2018 at our institution and compared them to a concurrent cohort of ruptured saccular anterior circulation aneurysms. A blister aneurysm was defined as an aneurysm that arises from a nonbranching point and demonstrates hemispherical anatomy on diagnostic angiography.

RESULTS

We identified 14 consecutive ruptured anterior circulation blister aneurysms. Thirteen aneurysms were treated operatively- 5 with clip remodeling and 8 with flow diversion embolization. While clip remodeling had a high intraoperative rupture rate (80%), there was only one (12.5%) intraoperative rupture with flow diversion embolization. Outcomes were worsened by delayed cerebral ischemia from vasospasm in patients with Fisher 3 hemorrhages from blister aneurysms (86%). The rate of delayed cerebral ischemia from vasospasm was significantly higher for ruptured blister aneurysms than for a concurrent cohort of ruptured saccular aneurysms (8.6%, P = 0.0001).

CONCLUSION

Ruptured Fisher grade 3 anterior circulation blister aneurysms have a significantly higher incidence of delayed cerebral ischemia from vasospasm compared to saccular aneurysms, regardless of the treatment modality.

Flow-diverting stent and delayed intracranial bleeding: the case for discussing acquired von Willebrand disease

A unique feature of the flow-diverting stent (FDS) has rendered it useful in the endovascular treatment of selected intracranial aneurysms for the last decade. Delayed aneurysmal rupture and intracranial parenchymal bleeding are two leading hemorrhagic complications after FDS. It has recently been shown for the first time that there is a relationship between FDS and reduced level of vWF activity in patients undergoing endovascular cerebral aneurysm treatment. Here, the current literature is reviewed in the context of this novel finding to propose an illustrative scenario that conceptually links implantation of FDS to delayed intracranial bleeding, through the mechanism of shear-induced activation of vWF. In this scenario, after FDS implantation, sustained release of activated vWF in association with platelets plays a pivotal role in the mechanisms of delayed intracranial hemorrhages.

Flow diverter embolization device for endovascular treatment of ruptured blister and wide necked very small aneurysms

Purpose

Ruptured blood blisters (BBA) and very small, wide necked aneurysms (VSA) remain challenging lesions to treat due to their small size, wide necks, and thin, fragile walls. In the present study, we reviewed our experience with these aneurysms treated by flow diversion.

Methods

A total of 18 patients with hemorrhage due to a ruptured BBAs and VSAs, treated with flow diversion between July 2014 and March 2016 were included in this study. We analyzed clinical and radiographic outcomes.

Results

A total of 12 (66.7%) VSAs and 6 (33.3%) BBAs were treated with flow diversion. Fifteen (83.3%) and three (16.7%) aneurysms were located on the internal carotid artery and the basilar artery, respectively. On admission, a GCS score of 15 and WFNS grade 1 were found in 14 (77.7%) patients, 3 patients had an admission GCS of 13 and WFNS grade 2, one had an admission GCS of 8 and WFNS of 4. Fisher CT grades 2, 3, and 4 were observed in 11 (61.1%), 1 (5.6%), and 6 (33.3%) patients, respectively. Flow diversion was performed on average 5.6 days after onset of hemorrhage. 6 months post-intervention angiography showed complete obliteration of the aneurysms in all patients.

Conclusion

Our findings indicate that flow diversion in the acute and subacute phase of hemorrhage is a reliable treatment for reducing complications in patients with BBAs and VSAs. In patients with poor clinical presentation it might be reasonable to delay treatment until the first signs of recovery become apparent.

Outcome of a Blood Blister-Like Aneurysm Treated by Clip-Reinforced Wrapping Technique Using Y-Shaped Temporalis Fascia for Perforator Protection

BACKGROUND

The optimal approach of blood blister-like aneurysms (BBAs) is debated. Wrapping has been reported to be an effective strategy, but artificial materials have often been used. In addition, perforator protection is difficult using this technique. In this case, we report a ruptured BBA of the left internal carotid artery (ICA) treated with a clip-reinforced wrapping technique using Y-shaped autologous temporalis fascia to protect the posterior communicating artery (PComA). The outcome was favorable.

CASE DESCRIPTION

A 48-year-old woman was admitted for subarachnoid hemorrhage. Digital subtraction angiography (DSA) revealed a BBA located opposite the PComA origin. A frontotemporal craniotomy was performed. The temporalis fascia was isolated from the temporalis muscle, and then tailored into a Y shape for the PComA to pass through. The diseased segment and the BBA were then wrapped by the Y-shaped temporalis fascia circumferentially. Two clips were applied to the fascia to reinforce the wrapping to fit snugly enough around the parent artery subsequently. DSA and computed tomography angiography scan postoperation showed that the BBA had not recurred, the supraclinoid segment of the left ICA had reconstructed well, and the PComA was unobstructed. The patient recovered without any sequelae during the 1-year follow-up period.

CONCLUSIONS

A clip-reinforced wrapping technique using Y-shaped temporalis fascia may be an effective method for treating BBAs located opposite the PComA origin. Long-term follow-up and large sample size studies, however, are necessary to validate this approach.

Clipping on Crossed Wrapping Method for Ruptured Blood Blister-Like Aneurysm of the Internal Carotid Artery: Technical Note and Long-Term Results

Background

We have been performing the clipping on crossed wrapping (COCW) method using 2 strips of cotton on patients with an internal carotid artery blood blister-like aneurysm (IC-BLA). This method is reliable in preventing the clips from slipping off and the aneurysm walls from being damaged during clipping, and it enables more appropriate and safer clipping. Here we report the technical details of this method and the long-term outcomes of patients receiving this procedure.

Methods

Fifteen of 1275 (1.5%) patients with a ruptured cerebral aneurysm who received treatment at the Saiseikai Kumamoto Hospital during the period from January 1, 1999, to December 31, 2016, had an IC-BLA. All 15 patients were treated with COCW, except for the first patient, who was treated using a single strip of cotton. The long-term outcome of the treatment was analyzed.

Results

The mean follow-up period was 74 months. The first patient experienced rerupture of an aneurysm 10 days after the operation. No complications or regrowth of an aneurysm were observed in the remaining 14 patients during the follow-up period, except for 1 patient who received a reoperation for the regrowth of an aneurysm. As the final outcome, the numbers of patients with a Modified Rankin Score of 0, 3, and 6 were 13, 1, and 1, respectively.

Conclusions

It is suggested that COCW is a treatment that enables safe and long-term management of lesions in IC-BLAs.

Endovascular coiling versus neurosurgical clipping for people with aneurysmal subarachnoid haemorrhage

BACKGROUND

Around 30% of people who are admitted to hospital with aneurysmal subarachnoid haemorrhage (SAH) will rebleed in the initial month after the haemorrhage if the aneurysm is not treated. The two most commonly used methods to occlude the aneurysm for prevention of rebleeding are microsurgical clipping of the neck of the aneurysm and occlusion of the lumen of the aneurysm by means of endovascular coiling. This is an update of a systematic review that was previously published in 2005.

OBJECTIVES

To compare the effects of endovascular coiling versus neurosurgical clipping in people with aneurysmal SAH on poor outcome, rebleeding, neurological deficit, and treatment complications.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (March 2018). In addition, we searched CENTRAL (2018, Issue 2), MEDLINE (1966 to March 2018), Embase (1980 to March 2018), US National Institutes of Health Ongoing Trials Register (March 2018), and World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (last searched March 2018). We also contacted trialists.

SELECTION CRITERIA

We included randomised trials comparing endovascular coiling with neurosurgical clipping in people with SAH from a ruptured aneurysm.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data, and assessed trial quality and risk of bias using the GRADE approach. We contacted trialists to obtain missing information. We defined poor outcome as death or dependence in daily activities (modified Rankin scale 3 to 6 or Glasgow Outcome Scale (GOS) 1 to 3). In the special worst-case scenario analysis, we assumed all participants in the group with better outcome with missing follow-up information had a poor outcome and those in the other group with missing data a good outcome.

MAIN RESULTS

We included four randomised trials involving 2458 participants (range per trial: 20 to 2143 participants). Evidence is mostly based on the largest trial. Most participants were in good clinical condition and had an aneurysm on the anterior circulation. None of the included trials was at low risk of bias in all domains. One trial was at unclear risk in one domain, two trials at unclear risk in three domains, and one trial at high risk in one domain.After one year of follow-up, 24% of participants randomised to endovascular treatment and 32% of participants randomised to the surgical treatment group had poor functional outcome. The risk ratio (RR) of poor outcome (death or dependency) for endovascular coiling versus neurosurgical clipping was 0.77 (95% confidence interval (CI) 0.67 to 0.87; 4 trials, 2429 participants, moderate-quality evidence), and the absolute risk reduction was 7% (95% CI 4% to 11%). In the worst-case scenario analysis for poor outcome, the RR for endovascular coiling versus neurosurgical clipping was 0.80 (95% CI 0.71 to 0.91), and the absolute risk reduction was 6% (95% CI 2% to 10%). The RR of death at 12 months was 0.80 (95% CI 0.63 to 1.02; 4 trials, 2429 participants, moderate-quality evidence). In a subgroup analysis of participants with an anterior circulation aneurysm, the RR of poor outcome was 0.78 (95% CI 0.68 to 0.90; 2 trials, 2157 participants, moderate-quality evidence), and the absolute risk decrease was 7% (95% CI 3% to 10%). In subgroup analysis of those with a posterior circulation aneurysm, the RR was 0.41 (95% CI 0.19 to 0.92; 2 trials, 69 participants, low-quality evidence), and the absolute decrease in risk was 27% (95% CI 6% to 48%). At five years, 28% of participants randomised to endovascular treatment and 32% of participants randomised to surgical treatment had poor functional outcome. The RR of poor outcome for endovascular coiling versus neurosurgical clipping was 0.87 (95% CI 0.75 to 1.01, 1 trial, 1724 participants, low-quality evidence). At 10 years, 35% participants allocated to endovascular and 43% participants allocated to surgical treatment had poor functional outcome. At 10 years RR of poor outcome for endovascular coiling versus neurosurgical clipping was 0.81 (95% CI 0.70 to 0.92; 1 trial, 1316 participants, low-quality evidence). The RR of delayed cerebral ischaemia at two to three months for endovascular coiling versus neurosurgical clipping was 0.84 (95% CI 0.74 to 0.96; 4 trials, 2450 participants, moderate-quality evidence). The RR of rebleeding for endovascular coiling versus neurosurgical clipping was 1.83 (95% CI 1.04 to 3.23; 4 trials, 2458 participants, high-quality evidence) at one year, and 2.69 (95% CI 1.50 to 4.81; 1 trial, 1323 participants, low-quality evidence) at 10 years. The RR of complications from intervention for endovascular coiling versus neurosurgical clipping was 1.05 (95% CI 0.44 to 2.53; 2 trials, 129 participants, low-quality evidence).

AUTHORS' CONCLUSIONS

The evidence in this systematic review comes mainly from one large trial, and long-term follow-up is available only for a subgroup of participants within that trial. For people in good clinical condition with ruptured aneurysms of either the anterior or posterior circulation the data from randomised trials show that, if the aneurysm is considered suitable for both neurosurgical clipping and endovascular coiling, coiling is associated with a better outcome. There is no reliable trial evidence that can be used directly to guide treatment in people with a poor clinical condition.

Stent placement in patients with acute subarachnoid haemorrhage: when is it justified?

PURPOSE

Endovascular stents are widely used for the elective treatment of cerebral aneurysms. Acute stenting is performed in the management of dissections, pseudo-aneurysms, broad-based aneurysms or as a 'bail out' measure after coil migration. The purpose of this study is to review the safety of using stents in acute subarachnoid haemorrhage.

METHODS

The stent registry of our institution was reviewed for procedures in patients with acute subarachnoid haemorrhage. Imaging studies were reviewed on the hospital's PACS system and the patients' notes were retrieved to assess complications and clinical outcomes. Procedures were analysed according to the type of stent, treatment indication, antiplatelet regime, complications and outcomes.

RESULTS

Between 2008 and 2016, 51 stents were placed during 50 stenting procedures in 49 patients with acute subarachnoid haemorrhage. This included 24 patients with saccular aneurysms, 10 with blister aneurysms, 10 dissections and five fusiform aneurysms. Stents were deployed in 'bail out' situations on eight occasions. In six cases, flow-diverting stents were used. Eighteen patients (37%) in the cohort suffered a stroke. Nine patients (18%) suffered persistent clinical deficits as a result of the stenting procedure, all but one of which occurred within 24 h. Two patients had a transient ischaemic episode, and there was evidence of asymptomatic ischaemia on imaging in four cases (8%). Five patients died, three (6%) as a result of procedural complications. Twelve patients (25%) required a further embolisation procedure.

CONCLUSION

The use of stents in acute subarachnoid haemorrhage incurs a considerable complication risk and should be reserved for exceptional circumstances.

Rerupture of a Blister Aneurysm After Treatment With a Single Flow-Diverting Stent

BACKGROUND AND IMPORTANCE

As the use of flow-diverting stents (FDSs) for intracranial aneurysms expands, a small number of case reports have described the successful treatment of blister aneurysms of the internal carotid artery with flow diversion. Blister aneurysms are uncommon and fragile lesions that historically have high rates of morbidity and mortality despite multiple treatment strategies. We report a case of rebleeding after treatment of a ruptured blister aneurysm with deployment of a single FDS.

CLINICAL PRESENTATION

A 29-year-old man presented with subarachnoid hemorrhage and a ruptured dorsal variant internal carotid artery aneurysm. Despite a technically successful treatment with a single FDS, a second catastrophic hemorrhage occurred during the course of his hospitalization.

CONCLUSION

This case highlights the risk of hemorrhage during the period after deployment of a single FDS. Ruptured aneurysms, especially of the blister type, are at risk for rehemorrhage while the occlusion remains incomplete after flow diversion.

ABBREVIATIONS

FDS, flow-diverting stentICA, internal carotid arterySAH, subarachnoid hemorrhage.

Clinical and angiographic outcomes in patients with intracranial aneurysms treated with the pipeline embolization device: intra-procedural technical difficulties, major morbidity, and neurological mortality decrease significantly with increased operator experience in device deployment and patient management

PURPOSE

Flow diversion constitutes a pivotal advancement in endovascular intracranial aneurysm treatment, but requires development of a new skill set. The aim of this study is to determine whether outcomes after treatment with the Pipeline Embolization Device improve with experience.

METHODS

We retrospectively reviewed all patients with intracranial aneurysms treated with Pipeline at two centers over a 4.5-year period. Baseline patient and aneurysm characteristics, complications, and angiographic outcomes were analyzed.

RESULTS

One hundred forty patients underwent 150 Pipeline procedures to treat 167 intracranial aneurysms during the study period, 109 women, mean age 55.4 years. One hundred twenty-six aneurysms were ICA, mean size 10.2 mm and mean neck 6.4 mm. Intra-procedural technical difficulties were higher during the first 75 procedures compared with the subsequent 75 (13.3 vs 2.7%; p = 0.03), as combined major morbidity and neurological mortality (14.7 vs 4%; p = 0.046). In multivariate regression analysis, increased operator experience with Pipeline remained an independent predictor of intra-procedural technical difficulties (p = 0.02, odds ratio (OR) 0.015, 95% CI 0.0004-0.55) and combined major morbidity and neurological mortality (p = 0.03, OR 0.16, 95% CI 0.03-0.84). At last follow-up, 123 aneurysms were completely occluded (81.5%, mean 24 months). In our cohort, age ≤ 53 years was an independent predictor of complete aneurysm occlusion at last follow-up (p = 0.001, OR 0.92, 95% CI 0.88-0.97). Five aneurysms were retreated (3.3%).

CONCLUSION

The Pipeline embolization device is an effective treatment for intracranial aneurysms. The risk of intra-procedural technical difficulties and combined major morbidity and neurological mortality decreases significantly with increased operator experience in Pipeline deployment and patient management.

Treatment of ruptured blood blister aneurysms using primary flow-diverter stenting with considerations for adjunctive coiling: A single-centre experience and literature review

Objective The objective of this article is to conduct a single-centre evaluation and quick literature review of the effectiveness of primary flow-diverter (FD) treatment of ruptured blood blister aneurysms (BBAs), with additional relevance of adjunctive coiling. Methods Patients presenting with subarachnoid haemorrhage (SAH) due to ruptured BBAs and subsequently treated with FDs were retrospectively selected from June 2010 to January 2017. Treatment techniques, angiographic data on occlusion rates and procedural success as well as clinical outcomes using the modified Rankin Scale (mRS) were collated. Cross-reference of results were made with available literature. Results Thirteen patients harbouring 14 BBAs were recruited. Of the 14 aneurysms, five (35.7%) showed immediate complete occlusion after the procedure (four of these five patients had adjunctive coiling). All of the aneurysms showed complete occlusion by the six- to nine-month control diagnostic angiogram. No rebleed or retreatment was experienced. Twelve of 13 (92%) patients had an mRS score of 0-1 at the last clinical follow-up. From the pooled data of the literature review, eventual aneurysm occlusion was achieved in 48/56 patients, with five patients requiring further endovascular treatment. In the clinical follow-up period, an mRS of 0-2 was recorded for 83.3% (45/54) of patients. Conclusion Endovascular reconstruction of BBAs using FD treatment is an effective method with good final clinical outcomes. Adjunctive use of coiling achieves higher incidence of immediate complete occlusion of BBAs.

Pipeline flow diversion of ruptured blister aneurysms of the supraclinoid carotid artery using a single-device strategy

OBJECTIVE

Ruptured blister aneurysms remain challenging lesions for treatment due to their broad, shallow anatomy and thin, fragile wall. Historical challenges with both open microsurgical approaches and intrasaccular endovascular approaches have led to increased use of flow diversion for management of these aneurysms. However, the optimum paradigm, including timing of treatment, use of dual antiplatelet therapy, and number of flow-diverter devices to use remains unknown. The authors describe their experience with ruptured blister aneurysms treated with flow diversion at their institution, and discuss rates of rebleeding and number of devices used.

METHODS

All patients presenting with subarachnoid hemorrhage from a ruptured blister aneurysm and treated with Pipeline flow diversion were identified. Patient demographic data, clinical status and course, need for external ventricular drain (EVD), timing of treatment, and angiographic details and follow-up were recorded.

RESULTS

There were 13 patients identified (11 women and 2 men), and 4 had multiple aneurysms. Two aneurysms were treated on initial angiography, with average time to treatment of 3.1 days for the remainder, after discussion with the family and institution of dual antiplatelet therapy. Device placement was technically successful in all patients, with 2 patients receiving 2 devices and the remainder receiving 1 device. There was 1 intraoperative complication, of a wire perforation causing intracerebral hemorrhage requiring decompressive craniectomy. Three patients had required EVD placement for management of hydrocephalus. There was no rebleeding from the target lesion; however, one patient had worsening intraventricular hemorrhage and another had rupture of an unrecognized additional aneurysm, and both died. Of the other 11 patients, 10 made a good recovery, with 1 remaining in a vegetative state. Nine underwent follow-up angiography, with 5 achieving complete occlusion, 2 with reduced aneurysm size, and 2 requiring retreatment for aneurysm persistence or enlargement. There were no episodes of delayed rupture.

CONCLUSIONS

Pipeline flow diversion is a technically feasible and effective treatment for ruptured blister aneurysms, particularly in good-grade patients without hydrocephalus. Patients with a worse grade on presentation and requiring EVDs may have higher risk for bleeding complications and poor outcome. There was no rebleeding from the target lesion with use of a single device in this series.

Endovascular treatment of blister aneurysms

Blister aneurysms are rare cerebrovascular lesions for which the treatment methods are reviewed here, with a focus on endovascular options. The reported pathogenesis of blister aneurysms varies, and hemodynamic stress, arterial dissection, and arteriosclerotic ulceration have all been described. There is consensus on the excessive fragility of blister aneurysms and their parent vessels, which makes clipping technically difficult. Open surgical treatment is associated with high rates of complications, morbidity, and mortality; endovascular treatment is a promising alternative. Among endovascular treatment options, deconstructive treatment has been associated with higher morbidity compared with reconstructive methods such as direct embolization, stent- or balloon-assisted direct embolization, stent monotherapy, and flow diversion. Flow diversion has been associated with higher technical success rates and similar clinical outcomes compared with non–flow diverting treatment methods. However, delayed aneurysm occlusion and the need for antiplatelet therapy are potential drawbacks to flow diversion that must be considered when choosing among treatment methods for blister aneurysms.

Current Treatment Strategies for Intracranial Aneurysms: An Overview

Intracranial aneurysm is a leading cause of stroke. Its treatment has evolved over the past 2 decades. This review summarizes the treatment strategies for intracranial aneurysms from 3 different perspectives: open surgery approach, transluminal treatment approach, and new technologies being used or trialed. We introduce most of the available treatment techniques in detail, including contralateral clipping, wrapping and clipping, double catheters assisting coiling and waffle-cone technique, and so on. Data from major trials such as Analysis of Treatment by Endovascular approach of Non-ruptured Aneurysms (ATENA), Internal Subarachnoid Trial (ISAT), Clinical and Anatomical Results in the Treatment of Ruptured Intracranial Aneurysms (CLARITY), and Barrow Ruptured Aneurysm Trial (BRAT) as well as information from other clinical reports and local experience are reviewed to suggest a clinical pathway for treating different types of intracranial aneurysms. It will be a valuable supplement to the current existing guidelines. We hope it could help assisting real-time decision-making in clinical practices and also encourage advancements in managing the disease.

Microsurgical versus endovascular interventions for blood-blister aneurysms of the internal carotid artery: systematic review of literature and meta-analysis on safety and efficacy

OBJECTIVE Blood-blister aneurysms (BBAs) of the internal carotid artery (ICA) have a poor natural history associated with high morbidity and mortality. Currently, both surgical and endovascular techniques are employed to treat BBAs; thus, the authors sought to perform a meta-analysis to compare the efficacy and safety of these approaches. METHODS A literature search of PubMed, MEDLINE, and Google Scholar online databases was performed to include pertinent English-language studies from 2005 to 2015 that discussed the efficacy and safety of either surgical or endovascular therapies to treat BBAs. RESULTS Thirty-six papers describing 256 patients with BBAs treated endovascularly (122 procedures) or surgically (139 procedures) were examined for data related to therapeutic efficacy and safety. Pooled analysis of 9 papers demonstrated immediate and late (mean 20.9 months) aneurysm occlusion rates of 88.9% (95% CI 77.6%-94.8%) and 88.4% (95% CI 76.7%-94.6%), respectively, in surgically treated patients. Pooled analysis of 12 papers revealed immediate and late aneurysm obliteration rates of 63.9% (95% CI 52.3%-74.1%) and 75.9% (95% CI 65.9%-83.7%), respectively, in endovascularly treated aneurysms. Procedure-related complications and overall poor neurological outcomes were slightly greater in the surgically treated cases than in the endovascularly treated cases (27.8% [95% CI 19.6%-37.8%] vs 26.2% [95% CI 18.4%-35.8%]), indicating that endovascular therapy may provide better outcomes. CONCLUSIONS Blood-blister aneurysms are rare, challenging lesions with a poor prognosis. Although surgical management potentially offers superior aneurysm obliteration rates immediately after treatment and at the long-term follow-up, endovascular therapy may have a better safety profile and provide better functional outcomes than surgery. A registry of patients treated for BBAs may be warranted to better document the natural course of the disease as well as treatment outcomes.

Current status of the treatment of blood blister-like aneurysms of the supraclinoid internal carotid artery: A review

Currently, the treatment of blood blister-like aneurysms (BBAs) of the supraclinoid internal carotid artery (ICA) is challenging and utilizes many therapeutic methods, including direct clipping and suturing, clipping after wrapping, clipping after suturing, coil embolization, stent-assisted coil embolization, multiple overlapping stents, flow-diverting stents, covered stents, and trapping with or without bypass. In these therapeutic approaches, the optimal treatment method for BBAs has not yet been defined based on the current understanding of BBAs of the supraclinoid ICA. Therefore, in this study, we aimed to review the literature from PubMed to discuss and analyze the pros and cons of the above approaches while adding our own viewpoints to the discussion. Among the surgical methods, direct clipping was the easiest method if the compensation of the collateral circulation of the intracranial distal ICA was sufficient or direct clipping did not induce stenosis in the parent artery. In addition, the clipping after wrapping technique should be chosen as the optimal surgical modality to prevent rebleeding from these lesions. Among the endovascular methods, multiple overlapping stents (≥3) with coils may be a feasible alternative for the treatment of ruptured BBAs. In addition, flow-diverting stents appear to have a higher rate of complete occlusion and a lower rate of retreatment and are a promising treatment method. Finally, when all treatments failed or the compensation of the collateral circulation of the intracranial distal ICA was insufficient, the extracranial-intracranial (EC-IC) arterial bypass associated with surgical or endovascular trapping, a complex and highly dangerous method, was used as the treatment of last resort.

Flow Diversion in Ruptured Intracranial Aneurysms: A Meta-Analysis

BACKGROUND

Flow diversion is now an established technique to treat unruptured intracranial aneurysms not readily amenable to endovascular coil embolization or open microsurgical occlusion. The role of flow-diverting devices in treating ruptured aneurysms is less clear.

PURPOSE

To estimate rates of angiographic occlusion and good clinical outcome in patients with ruptured intracranial aneurysms treated with flow-diverting devices.

DATA SOURCES

Systematic review of Ovid MEDLINE, PubMed, Cochrane databases, and EMBASE from inception to December 2015 for articles that included ruptured aneurysms treated with flow diversion.

STUDY SELECTION

One hundred seventy-two records were screened, of which 20 articles contained sufficient patient and outcome data for inclusion.

DATA ANALYSIS

Clinical and radiologic characteristics, procedural details, and outcomes were extracted from these reports. Aggregated occlusion rates and clinical outcomes were analyzed by using the Fisher exact test (statistical significance, α = .05).

DATA SYNTHESIS

Complete occlusion of the aneurysm was achieved in 90% of patients, and favorable clinical outcome was attained in 81%. Aneurysm size greater than 7 mm was associated with less favorable clinical outcomes (P = .027). Aneurysm size greater than 2 cm was associated with a greater risk of rerupture after treatment (P < .001).

LIMITATIONS

Observational studies and case reports may be affected by reporting bias.

CONCLUSIONS

Although not recommended as a first-line treatment, the use of flow diverters to treat ruptured intracranial aneurysms may allow high rates of angiographic occlusion and good clinical outcome in carefully selected patients. Aneurysm size contributes to treatment risk because the rerupture rate following treatment is higher for aneurysms larger than 2 cm.

Endovascular isolation of intracranial blood blister-like aneurysms with Willis covered stent

Objective

Intracranial blood blister-like aneurysm (BBA) is a rare type of aneurysm that lacks all layers of the arterial wall. These fragile aneurysms have the propensity to rupture with minimal manipulation, which makes them hazardous and difficult to treat. The present study evaluated the safety and feasibility of endovascular treatment of BBAs with the Willis covered stent.

Materials

Thirteen patients (7 men and 6 women, age range 28–68 years) who presented with ruptured BBAs and were treated with the Willis covered stent were retrospectively reviewed. Results of the procedures and treatment-related complications were recorded. Angiographic and clinical follow-ups were performed 4–6 months after the procedure.

Results

Placement of the covered stent was successful in all patients. Immediate angiography showed complete aneurysm occlusion in 12 patients while one patient showed a mild endoleak. This high rate of aneurysm exclusion ensured the security of postoperative antiplatelet treatment. Occlusion of the ophthalmic artery occurred in two patients and occlusion of the anterior choroidal artery occurred in one patient; however, none of them showed acute or delayed clinical symptoms. Thrombosis, aneurysm rupture, and other complications did not develop in any case. Angiographic follow-up showed complete aneurysm exclusion without aneurysm recurrence in any patients. Only two patients showed asymptomatic mild to moderate in-stent stenosis. All patients had satisfactory clinical outcomes (modified Rankin Scale score ≤1).

Conclusions

Willis covered stent implementation may be safe and feasible for BBAs. This strategy might be a promising option for this high-risk type of aneurysm.

Flow diversion with Pipeline Embolic Device as treatment of subarachnoid hemorrhage secondary to blister aneurysms: dual-center experience and review of the literature

Background

Aneurysmal subarachnoid hemorrhage (aSAH) secondary to blister-type aneurysms (BAs) is associated with high morbidity and mortality. Microsurgical clipping or wrapping and/or use of traditional endovascular techniques to repair the lesion result in frequent regrowth and rebleeds and ultimately high fatality rates. Because of the purely endoluminal nature of arterial reconstruction, flow diversion may represent an ideal option to repair ruptured BAs.

Methods

We performed a retrospective analysis of our database including all consecutive patients with aSAH secondary to BAs treated with the Pipeline Embolic Device (PED) between November 2013 and November 2015 in two institutions. We collected basic patient demographics, aneurysm size, location, number and sizes of PEDs used, use of coiling, 30-day modified Rankin Scale (mRS) score, and follow-up imaging data.

Results

Ten cases of aSAH were found as a result of a ruptured BA. Patients had a mean age of 47.2 years (range 27–68). Mean Hunt and Hess score was 1.6 (range 1–4). Lesions were predominantly left-sided, mostly along the dorsal aspect of the internal carotid artery, either paraclinoid or paraophthalmic (8/10). In two patients the BA was located in the left middle cerebral artery. All lesions were very small (mean 1.4×1.5 mm; range 0.75–2.1 mm). Placement of a single PED resulted in immediate occlusion or near-occlusion of the BA in 9 out of 10 patients. Nine patients did very well; eight had a 90-day mRS score of 0 and one had a 90-day mRS score of 1. Follow-up digital subtraction angiography was performed in all patients (mean 15 months; range 7–24). In the surviving nine patients there was complete occlusion of the BA on long-term follow-up angiography.

Conclusions

Repair of ruptured BA with PED may be a safe and durable option.

Feasibility, Safety, and Efficacy of Flow-Diverting Stent-Assisted Microsphere Embolization of Fusiform and Sidewall Aneurysms

BACKGROUND

Treatment of wide-necked internal carotid artery aneurysms is frequently associated with incomplete occlusion and high recurrence rates. Furthermore, platinum coils cause strong beam-hardening artifacts, hampering subsequent image analyses.

OBJECTIVE

To assess the feasibility, safety, and efficacy of flow-diverting, stent-assisted microsphere embolization of fusiform and sidewall aneurysms in vitro and in vivo.

METHODS

Using a recirculating pulsatile in vitro flow model, 5 different aneurysm geometries (inner/outer curve, narrow/wide neck, and fusiform) were treated (each n = 1) by flow-diverting stent (FDS) implantation and subsequent embolization through a jailed microcatheter using calibrated microspheres (500-900 μm) larger than the pores of the FDS mesh. Treatment effects were analyzed angiographically and by micro computed tomography. The fluid of the in vitro model was filtered to ensure that no microspheres evaded the aneurysm. The experiment was repeated once in vivo.

RESULTS

In vitro, all 5 aneurysms were safely and completely occluded by FDS-assisted microsphere embolization. Virtually complete aneurysm occlusion was confirmed by angiography and micro computed tomography. No microspheres escaped into the circulation. The experiment was successfully repeated in 1 pig with a sidewall aneurysm generated by vessel occlusion. An embolic protection system placed distally of the FDS in vitro and in vivo (each n = 1) contained no microspheres after the embolization. Thus, no microspheres were lost in the circulation, and the use of an embolic protection system seems feasible to provide additional safety.

CONCLUSION

FDS-assisted microsphere embolization of fusiform and sidewall aneurysms is feasible and yields virtually complete aneurysm occlusion while avoiding coil-associated beam-hardening artifacts.