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

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.

Flow Diverter Combined with Coil Embolization for Acutely Ruptured Intracranial Aneurysms: A Single Center Experience

BACKGROUND

Extensive research has confirmed the safety and effectiveness of flow diverters in the treatment of unruptured intracranial aneurysms. However, their use in cases of acute rupture remains a subject of debate.

METHODS

This study was conducted as a single-center retrospective investigation from January 2018 to January 2022 and included patients with acutely ruptured intracranial aneurysms (within three days of rupture) who were treated using the Pipeline Embolization Device with adjunctive coil embolization. Patient demographics, operative procedures, and outcomes were analyzed. Antiplatelet therapy included intra-arterial tirofiban and postoperative dual therapy with clopidogrel and aspirin.

RESULTS

A total of 21 patients (5 males, 16 females) diagnosed with acutely ruptured intracranial aneurysms were included in this study. The aneurysm types included 7 blood blister-like aneurysms (30.0%), 3 dissecting (14.3%), and 1 fusiform aneurysm (4.8%). Perioperative complications occurred in 2 patients (9.5%), and both cases involved thrombogenesis. Nineteen patients completed digital subtraction angiography during follow-up, with an average follow-up time of 8.7 months (5 - 18 months). Results showed a complete embolization rate of 94.7% (18/19), with a partial aneurysm still present in 1 patient. A total of 90.4% (19/21) of patients had a favorable prognosis (modified Rankin Scale score = 0 - 2).

CONCLUSIONS

The Pipeline Embolization Device with adjunctive coil embolization proved to be a viable option for managing acutely ruptured intracranial aneurysms, notwithstanding the potential for ischemic complications.

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.

Utility of flow diverters in treatment of acutely ruptured uncoilable aneurysms of the posterior circulation of the brain

PURPOSE

Aim of this study is to evaluate safety and efficacy of flow diverters (FDs) in treatment of acutely ruptured posterior circulation aneurysms MATERIALS AND METHODS: Databases of three participating institutions were retrospectively scanned for patients in whom FD placement was attempted for treatment of acutely ruptured vertebrobasilar aneurysms. An interval of 14 days or fewer between the latest ictus and treatment was used as inclusion criterion. Patients with dolichoectasia of vertebrobasilar arteries were excluded. If necessary, adjunctive techniques including coiling or stenting were utilized. Clinical outcomes were graded using mWFNS (modified World Federation of Neurosurgical Societies Scale) and mRS (modified Rankin Scale). Aneurysmal occlusion was defined as Raymond-Roy Class 1. Spearman's (ρ) test was used to assess the correlation between variables. Univariate and multivariate logistic regression were used to assess outcomes.

RESULTS

31 patients (25 women, mean age: 52.7 ± 15.2) harboring 32 aneurysms (16 non-saccular, mean size: 11.4 ± 7 mm) were included. Mean number of FDs used was 1.22 ± 0.42. In six cases, adjunctive coiling and in five cases, apposing stent placement were used. Overall mortality rate and procedure-related mortality rates were 22.5% (7/31) and 9.6% (3/31), respectively. At a mean imaging follow-up of 17.2 ± 12.6 months, total occlusion was achieved in 22 aneurysms (91.6%). Univariate analysis showed that mortality was positively correlated with vasospasm (ρ = 0.600, p < 0.05), higher mWFNS Scale (ρ = 0.685, p < 0.05), higher modified Fischer Score (ρ = 0.609, p < 0.05), higher mRS (ρ = 0.594, p < 0.05) on admission and negatively correlated with saccular morphology (ρ = -0.529, p < 0.05). Multivariate logistic regression identified mWFNS on admission as a significant predictor. (OR: 7.148, 95% CI 1.777-28.758, p: 0.01). Adjunctive coiling positively correlated with aneurysm occlusion. (ρ = 0.522, p < 0.05).

CONCLUSION

The procedure-related morbidity and mortality is not negligible. However, the risks and efficacy associated with FDs are acceptable, especially when adjunctive coiling is possible, given the lack of treatment alternatives.

Stent-assisted Coiling vs. Flow Diverter for Treating Blood Blister-like Aneurysms : A Proportion Meta-analysis

PURPOSE

Blood blister-like aneurysms (BBAs) are rare vascular lesions and a therapeutic challenge. Although endovascular treatment of BBA is a promising approach, the optimal treatment remains controversial. The purpose of this study was to compare the safety and efficacy of stent-assisted coiling (SAC) and flow diverter (FD) in the management of BBAs.

METHODS

A proportion meta-analysis including a published series of BBAs treated with endovascular approaches from 2009 to 2020 including SAC and FD was performed by searching English language studies via MEDLINE and EMBASE.

RESULTS

The 32 studies included 16 based on SAC and 16 involving FD. The long-term complete occlusion rate was higher in FD (89.26%, 95% confidence interval, CI 82.93-94.26%, I² = 14.42%) than in SAC (70.26%, 95% CI 56.79-82.13%, I² = 70.60%). The rate of aneurysm recanalization was lower in FD (4.54%, 95% CI 1.72-8.16%, I² = 0%) than in SAC (25.38%, 95% CI 14.44-38.19%, I² = 67.31%). Rates of mortality, favorable functional outcome, procedural complications, and rebleeding showed no differences between the two procedures.

CONCLUSION

In a proportion meta-analysis comparing FD with SAC, the FD was associated with more favorable angiographic outcomes but similar complications and clinical outcomes.

Outcomes after Flow Diverter Treatment in Subarachnoid Hemorrhage: A Meta-Analysis and Development of a Clinical Prediction Model (OUTFLOW)

Background: patients with a subarachnoid hemorrhage (SAH) might need a flow diverter (FD) placement for complex acutely ruptured intracranial aneurysms (IAs). We conducted a meta-analysis and developed a prediction model to estimate the favorable clinical outcome after the FD treatment in acutely ruptured IAs. Methods: a systematic literature search was performed from 2010 to January 2021 in PubMed and Embase databases. Studies with more than five patients treated with FDs within fifteen days were included. In total, 1157 studies were identified. The primary outcome measure was the favorable clinical outcome (mRS 0–2). Secondary outcome measures were complete occlusion rates, aneurysm rebleeding, permanent neurologic deficit caused by procedure-related complications, and all-cause mortality. A prediction model was constructed using individual patient-level data. Results: 26 retrospective studies with 357 patients and 368 aneurysms were included. The pooled rates of the favorable clinical outcome, mortality, and complete aneurysm occlusion were 73.7% (95% CI 64.7–81.0), 17.1% (95% CI 13.3–21.8), and 85.6% (95% CI 80.4–89.6), respectively. Rebleeding occurred in 3% of aneurysms (11/368). The c-statistic of the final model was 0.83 (95% CI 0.76–0.89). All the studies provided a very low quality of evidence. Conclusions: FD treatment can be considered for complex ruptured IAs. Despite high complication rates, the pooled clinical outcomes seem favorable. The prediction model needs to be validated by larger prospective studies before clinical application.

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.

Endovascular reconstruction of iatrogenic internal carotid artery injury following endonasal surgery: a systematic review

The objective of this study is to provide an update on endovascular treatments for iatrogenic internal carotid artery (ICA) injuries following endonasal surgery. A systematic review of the literature was performed by using Medline, Cochrane library, and Scopus from 1999 to 2019. We used a combination of the MeSH terms "internal carotid artery," "iatrogenic disease," and "endovascular procedure." Twenty-six articles including 46 patients were identified for in this systematic review. The mean age of the patients was 49 years (CI: ± 4.2). The most common site of ICA injury was in cavernous segment (18 patients; 39%). The most common type of iatrogenic ICA injury was a traumatic pseudoaneurysm documented in 28 patients (60%). Endoluminal reconstruction was performed using covered stents in 28 patients, the Pipeline embolization device (PED) in 13 patients, the Surpass flow diverter device in three, the SILK flow diverter in one, and one case was treated using a combined approach of a covered stent and a PED. Flow diversion and covered stents resulted in a good clinical outcome in 94% and 89% of patients, respectively. This difference did not reach statistical significance (p = 1.0). Even though this systematic review was limited due to articles of small sample sizes and considerable heterogeneity, the results indicate that flow diverting devices and covered stents are good therapeutic options for endoluminal reconstruction of iatrogenic ICA injuries following endonasal surgery.

Comparison of clinical and histopathological characteristics of short-term progressive and non-progressive blood blister-like aneurysms

BACKGROUND

Many blood blister aneurysms (BBAs) have been documented with a rapid progression history in repeated angiography. The underlying mechanism and clinical significance remained elusive. This current study aims to clarify the clinical and histopathological differences between short-term progressive BBA and non-progressive BBAs.

METHODS AND MATERIALS

Eighty-one patients with BBAs were consecutively included for this single-center retrospective analysis. Clinical and radiological data on these patients were retrieved from 2017 to 2019. BBAs were defined as either progressive or non-progressive based on observed growth based on repeated imaging. Histopathological examinations of a saccular aneurysm, a progressive BBA, and a non-progressive BBA were conducted using representative aneurysm samples.

RESULTS

Among all enrolled patients, 26 of the them were identified with progressive BBAs, while the other 55 with non-progressive BBAs. Progressive BBAs were diagnosed significantly earlier in angiography (3.36 ± 0.61 vs. 6.53 ± 1.31 days, p < 0.05) and showed a higher presence rate of daughter sacs (61.5 vs. 38.2%, p < 0.05). Three different progression patterns were identified. BBAs that developed daughter sac enlargement are diagnosed significantly later than BBAs exhibiting other progression patterns. Patients with progressive and non-progressive BBAs exhibited similar overall clinical outcomes and incidence for complications. For patients with non-progressive BBAs, microsurgery appears to be inferior to endovascular treatment, while for patients with progressive BBAs, the short-term outcomes between microsurgery and endovascular treatment were identical. Histopathological analysis revealed that both subtypes shared a similar pseudoaneurysms structure, but non-progressive BBAs had more histologically destructed aneurysm wall with less remnant fibrillar collagen in adventitia.

CONCLUSIONS

Progressive and non-progressive BBAs may not be distinct pathological lesions but represent different stages during the BBA development. Early intervention, regardless of treatment methods, is recommended for salvageable patients with progressive BBAs, but microsurgery should be performed with caution for non-progressive BBAs due to increased surgical risk.