The efficacy of endovascular treatment of ruptured blood blister-like aneurysms using stent-assisted coil embolization

Coiling Variations for Treatment of Ruptured Intracranial Aneurysms: A Meta-Analytical Comparison of Comaneci-, Stent-, and Balloon-Coiling Assistance Techniques

BACKGROUND

Wide-necked aneurysms represent a challenge for treatment in the setting of acute subarachnoid hemorrhage. Stent-assisted coiling (SAC) and balloon-assisted coiling (BAC) are well-known techniques for treating wide-necked aneurysms. Comaneci-assisted coiling (CAC) is a newer technique involving temporary stent deployment to assist aneurysm coiling. We aim to present the first meta-analysis comparing these treatments of ruptured aneurysms.

METHODS

Following PRISMA guidelines, PubMed and Embase databases were queried from earliest records to July 2022 for literature reporting SAC, BAC, or CAC of ruptured intracranial aneurysms. A meta-analysis of identified articles was performed.

RESULTS

Of the 571 articles queried, 64 articles were included. One study reported BAC and SAC, 8 reported BAC, 52 reported SAC, and 3 reported CAC. These studies comprised 3153 patients with 3207 ruptured aneurysms treated with CAC (161 patients and aneurysms), BAC (330 patients and aneurysms), and SAC (2662 patients, 2716 aneurysms). Rates of periprocedural thromboembolic or hemorrhagic complications, overall or procedure-related mortality, immediate complete occlusion, retreatment, and length of angiographic follow-up did not differ significantly between SAC and BAC. Periprocedural thromboembolic (P = 0.03) and hemorrhagic (P = 0.01) complication rates were higher with BAC than CAC. Periprocedural thromboembolic (P = 0.03) and hemorrhagic (P < 0.0001) complication rates were higher with SAC than CAC. Complete aneurysm occlusion rates (P = 0.033) were higher with CAC than BAC. No significant differences were present in CAC versus BAC or SAC retreatment rates.

CONCLUSIONS

CAC was associated with lower hemorrhagic and thromboembolic complication rates and demonstrated similar complete occlusion and residual retreatment rates to those for BAC and SAC.

Long-Term Outcomes of Ruptured Blood Blister-Like Aneurysms with Multiple (≥2) Overlapping Stents and Coiling: A Single-Center Experience

OBJECTIVE

To evaluate the long-term feasibility of multiple overlapping stents (≥2) with or without coiling for treating blood blister-like aneurysms (BBAs).

METHODS

BBAs treated with stent-assisted coiling or stent-only therapy wasincluded. BBAs with atypical anatomical locations, other endovascular or surgical techniques performed, and delayed treatment (>48 hours) were excluded. Medical records of patients and procedures were retrospectively reviewed.

RESULTS

Seventeen patients with BBAs were identified, and 15 were treated with stent-assisted coiling and 2 with stent-only therapy. Triple overlapping stents were performed in seven patients, double stents in nine, and a single stent with coiling in 1. One patient experienced in-stent fibrin formation and received intra-arterial tirofiban. Complementary treatment was required in four patients. Three patients were initially treated with double (3/9) and 1 with triple stents (1/7). Three recurred in the acute period (≤6 weeks) and 1 recurred 14 months after treatment. Three of 17 patients with Hunt Hess grade 5 died early. Thirteen patients were available for long-term angiographic follow-up (13.8 ± 8.9 months). Final angiography showed complete aneurysm occlusion in all patients without in-stent stenosis or perforating vessel occlusion. Clinical follow-up data were available for all 14 surviving patients (66.8 ± 40.9 months). Eight patients had favorable outcomes, five had unfavorable outcomes, and 1 died of a subarachnoid hemorrhage-unrelated cause. Delayed infarct or hemorrhage was not documented.

CONCLUSIONS

Even in the era of flow diverter stents, the use of multiple overlapping stents with or without coiling can be a feasible alternative for treating ruptured BBAs.

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.

Case Series of Endovascular Therapy for Blood Blister-Like Aneurysm in Acute Phase

Objective

Blood blister-like aneurysms (BBAs) of the internal carotid artery are highly challenging to treat due to their variable morphology and tendency for rupture and regrowth. Here, we report a single-institution experience of endovascular therapy (EVT) for BBA treatment.

Methods

We retrospectively reviewed patients with ruptured BBA from 2006 to 2019. All patients in whom BBA was treated with EVT were included. Patients' aneurysmal characteristics, progression status, aneurysm occlusion on follow-up angiography, and modified Rankin Scale (mRS) score were recorded.

Results

A total of 11 patients (5 women and 6 men) with the mean age of 46 ± 10 years were included in this study. As initial treatment, 9 patients were treated with stent-assisted coiling (SAC). Immediate angiographic results showed that 2 cases were body filling, 4 were neck remnant, and 3 were complete obliteration. Perioperative ischemic complications were not observed. On postoperative day 1, 2 patients suffered from rerupture, and their prognoses were poor. Retreatments were performed in 5 patients. Parent artery occlusion (PAO) was performed in 6 patients including 2 initial treatments and 4 retreatments. Symptomatic infarction developed in 2 patients. In 3 patients, bypass in combination with PAO was performed. Clinical data revealed discharge mRS scores of 0-2 and 3-6 in 4 and 7 patients, respectively.

Conclusion

SAC is effective for the management of BBA. Careful follow-up and response are necessary after treatment with SAC.

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.

Endovascular treatment of blood blister-like aneurysms of internal carotid artery: Stent-assisted coiling and pipeline flow diversion

OBJECTIVE

To report the stent-assisted coil embolization and flow diversion treatments of blood-blister-like aneurysms based on the theory of acute dissection of the internal carotid artery.

PATIENTS AND METHODS

From July 2016 through July 2020, 27 patients presenting with subarachnoid hemorrhage (SAH) due to rupture of internal carotid artery blood blister-like aneurysms were subjected to endovascular treatment with stent-assisted coiling or Pipeline flow diversion. Clinical outcomes were evaluated using modified Rankin Scale score (mRS).

RESULTS

A proximal stenosis caused by angiopathology adjacent to aneurysms were found on internal carotid artery angiograms in all 27 cases. The angiopathology combining with the aneurysms implement that acute dissection of the supraclinoid segment of the internal carotid artery indicated the pathogenesis of blood blister-like aneurysm formation. All aneurysms were treated successfully with alleviation of the adjacent angiopathology after stenting on angiograms. During 1-12 months, mean 3.5 months, complete aneurysm obliteration without adjacent stenosis were found in 25(92.6%) patients. Two (7.4%) cases of recanalization were retreated with complete obliteration at 1 week and 3 months after initial treatment. Clinical mRS 0 and 1 outcomes were observed in 23(85.2%) patients, mRS 2 in 3(11.1%) patients and mRS 6 in 1(3.7%) not related to aneurysm treatment during follow-up.

CONCLUSIONS

Acute focal dissection of supraclinoid segment of internal carotid artery underlies the development of blood blister-like aneurysm. Stent-assisted coiling and flow diversion treatments constitute appropriate treatment based on the arterial dissection pathology.

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.

The formation mechanism of acute dissection of blood blister-like aneurysm and its implication of endovascular treatment

BACKGROUND

Acute mural dissection of the anterior wall of the internal carotid artery which may contribute to the development of blood blister-like aneurysms (BBLAs) was postulated, and stenting or flow diversion treatment across the soi-disant aneurysm was reported in this study.

METHODS

From December 2016 to December 2018, 8 patients presenting with subarachnoid hemorrhage (SAH) due to BBLA were subjected to endovascular treatment with stent-assisted coiling. Clinical outcomes were evaluated using a clinical outcome score scale.

RESULTS

Based on angiograms, pathologic change involving the supraclinoid segments of the internal carotid artery (ICA) adjacent to BBLA was found in all patients. This pathologic change meant a focal dissection of the supraclinoid segment of the ICA which constituted the pathogenesis of BBLAs. Closed-cell, open-cell, and braided stents were used in 1, 1, and 6 patients, respectively. Complete obliteration was achieved following endovascular treatment among all 8 patients harboring BBLA. One re-bleeding successive to a closed-cell stent across the aneurysmal neck was observed. Follow-up angiograms revealed stable complete exclusion of all BBLAs from the parent vessel at 3 to 8 months. All patients had a favorable clinical outcome score of 0-1.

CONCLUSIONS

Acute dissection of a focal point of the intracranial vessels underlies the development of BBLAs. Open-cell and braided-cell stent-assisted coiling may constitute appropriate treatment due to good apposition against the vascular walls. Adjunctive coils may facilitate immediate complete occlusion of BBLAs.

Is Stent-Assisted Coil Embolization for the Treatment of Ruptured Blood Blister-Like Aneurysms of the Supraclinoid Internal Carotid Artery Effective? : An Analysis of Single Institutional Experience with Pooled Data

Objective

Given the high risk of rebleeding and recurrence of blood blister-like aneurysms (BBAs), we treated ruptured BBAs of the internal carotid artery (ICA) with stent-assisted coil embolization (SAC). This study aimed to evaluate the efficacy and safety of SACs.

Methods

We retrospectively reviewed clinical and radiological data from eight patients with ruptured BBAs of the supraclinoid ICA. The modified Rankin Scale (mRS) was used to assess clinical outcomes, while radiological outcomes were evaluated on angiographs. For a pooled analysis, data from literature reporting the outcomes of ruptured BBAs treated with SAC were collected and analyzed in conjunction with our data.

Results

In our cohort, the mean Raymond classification score was 1.57±0.53 immediately after initial endovascular treatment. There were no perioperative complications or rebleeding events during the follow-up period. The mean mRS score at patient discharge was 1.00±0.81 and improved to 0.28±0.48 by the last follow-up day. The recurrence rate was 25% with an asymptomatic presentation and successful treatment with multiple stent insertion. Pooled analysis of 76 cases of SAC revealed a complete occlusion rate immediately after treatment of 54.8%, rebleeding rate 7.94%, and recurrence rate 24.2%. Good clinical outcomes with mRS score 0–2 were observed in 89.9% by the last clinical follow-up. Total mortality rate was 7.7%.

Conclusion

This treatment appears to not only minimize the hemodynamic burden on the fragile dome specific to this type of aneurysm, but also provides an opportunity for safe and effective treatment in recurrent cases.

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.

Endovascular Treatment of Complex Vascular Diseases of the Internal Carotid Artery Using the Willis Covered Stent: Preliminary Experience and Technical Considerations

Purpose: The Willis covered stent (WCS) is used to treat complex vascular diseases of the internal carotid artery; however, its performance requires further investigation. This study aimed to present our single-center clinical results and experience of endovascular repair of complex vascular diseases of the internal carotid artery using the WCS.

Methods: Patients who presented with complex vascular diseases of the internal carotid artery and who were treated with the WCS from December 2013 to September 2018 were retrospectively reviewed. Procedural results, perioperative complications, incidence of endoleak, and follow-up outcomes were analyzed.

Results: Sixty-five patients were enrolled. A total of 25 large aneurysms, 10 pseudoaneurysms, 14 blood blister-like aneurysms, 11 carotid–cavernous fistulas, and 5 surgical injuries were assessed. WCS placement was successful in all patients. Immediate angiography showed that complete repair of the target artery was achieved in 56 patients (86.2%). Endoleak was observed in nine patients, including seven type I endoleaks and two type II endoleaks. Occlusion of a side-branch vessel occurred in four patients. Acute in-stent thrombosis occurred in one patient. No ischemic or hemorrhagic events or other complications developed during the perioperative and follow-up periods. Angiographic follow-up (mean duration, 12 ± 3.29 months) was performed in 60 patients and showed complete target artery repair in 58 patients, and asymptomatic mild to moderate in-stent stenosis was observed in four patients. Slight endoleak persisted in two patients without enlargement or rupture of the residual lumen.

Conclusion: WCS implantation is safe, feasible, and efficacious for endovascular repair in patients with complex vascular diseases of the internal carotid artery, showing excellent short-term target artery patency and clinical outcomes.

Using overlapping low-profile visualized intraluminal support stent-assisted coil embolization for treating blood blister-like aneurysms of the internal carotid artery

Blood blister-like aneurysm (BBA) of the internal carotid artery (ICA) is highly challenging to treat owing to its variable morphology and tendency for rupture and regrowth. In this study, we attempted to discuss the key techniques for overlapping low-profile visualized intraluminal support (LVIS) stent-assisted coil embolization, which is used for treating BBAs in our center. Clinical characteristics, endovascular treatment details, outcomes, and follow-up results of 13 patients with BBA treated at our center were retrospectively evaluated in this study. Overlapping LVIS stent-assisted coil embolization was successfully performed in all 13 patients of ruptured BBAs located in the ICAs. Recurrence of aneurysm was observed in 4 cases (30.8%) during the angiographic follow-up; in 2 of these cases, spontaneous healing was observed after discontinuation of antiplatelet therapy. Further, 2 patients with recurrence underwent endovascular treatment with complete obliteration of the aneurysm in one and occlusion of the parent artery after Onyx embolization and stent placement in the other. The overall obliteration rate of the BBAs was 92.3% (12/13). One patient (7.7%) developed intraoperative rupture of the aneurysm with coils protruding outside; however, no severe hemorrhage or neurological dysfunction occurred owing to timely embolization. Overlapping LVIS stent-assisted coil embolization is effective for management of BBA of the ICA. Appropriate adjustment in antiplatelet therapy may improve healing in recurrent cases.

A Patient with a Ruptured Blood Blister-like Aneurysm of the Internal Carotid Artery in Whom Two LVIS Stents Were Inserted

Objective

We report a case in which multiple overlapping low-profile visualized intraluminal support (LVIS) stents were used as monotherapy for ruptured blood blister-like aneurysm (BBA) of the internal carotid artery (ICA).

Case Presentation

A 48-year-old female presented to the emergency room with acute-onset headache. She was alert without neurological deficit with subarachnoid hemorrhage (SAH) Hunt and Kosnik grade I. Emergency angiography revealed a BBA from the supraclinoid ICA. This aneurysm had a small diameter, which makes coil embolization difficult. Therefore, we planned to use multiple overlapping LVIS stents as monotherapy for the ruptured aneurysm. The postoperative course was uneventful without rebleeding. The patient exhibited no neurological deficits on the clinical follow-up at 1 year.

Conclusion

Multiple overlapping LVIS stents as monotherapy is useful for ruptured BBAs of the ICA.

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.

Three-dimensional shaping technique for coil placement using the steam-shaped microcatheter for ruptured blood blister-like aneurysm

Treatment of blood blister-like aneurysm (BBA) is a challenge due to its unfavourable morphology, small size and the friable neck of BBA. In the management of ruptured BBA, coil placement can be achieved by stent-assisted coil embolisation. We propose to incorporate a new technique using a steam-shaped microcatheter to improve safety. A 59-year-old woman was transferred to our hospital and diagnosed with subarachnoid haemorrhage (SAH) due to a ruptured BBA of the left internal carotid artery (ICA) at the C2 portion. For coil embolisation, we selected the aneurysm sac using a three-dimensional shaping technique and the jailing method. Post-embolisation angiography revealed complete occlusion of the aneurysmal sac. For safe treatment and stability of BBA, the shape of the catheter tip and the distal portion of the microcatheter are two important factors to consider. The proposed technique could help resolve the problem of catheter shaping in the treatment of BBA.

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.

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.

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.

Endovascular treatment of ruptured blood blister-like aneurysms with multiple (≥3) overlapping Enterprise stents and coiling

BACKGROUND

Blood blister-like aneurysms (BBAs) are difficult to treat both surgically and endovascularly, and the optimal treatment remains controversial. The aim of this study was to evaluate the clinical and angiographic feasibility of multiple overlapping stents (≥3) with coiling for treating BBA.

METHODS

A retrospective review from four institutions identified ten patients with ruptured BBAs who were treated with multiple overlapping stents (≥3). We included both the patients who were initially treated with more than three stents and those who eventually had more than three stents as a consequence of retreatment. Angiographic results (Raymond scale), clinical outcomes (mRS) and treatment courses were evaluated.

RESULTS

Initially, seven patients were treated with triple stents and three with double stents. Immediate angiographic results revealed that six aneurysms were Raymond grade 1, three were grade 2, and one was grade 3. Complementary treatment was required in four patients. All three patients who were initially treated with double stents required complementary treatment (100 %). One patient required complementary treatment among the seven patients who were initially treated with three stents (14.3 %). The last follow-up angiography (mean, 12.2 ± 14.7 months; range, 1-44 months) revealed grade 1 in all ten patients. Clinical data (mean follow-up period, 18.2 ± 20.1 months; range, 1-62 months) revealed eight patients with a mRS score of 0-2 and two with mRS 3-5.

CONCLUSIONS

Even in the era of flow diverter stents, multiple overlapping stents (≥3) with coiling could be a feasible alternative for treating ruptured BBAs. Additional experience and follow-up are needed in a larger series to state the long-term efficacy of this treatment.

Endovascular Treatment of Ruptured Blister-Like Aneurysms: A Systematic Review and Meta-Analysis with Focus on Deconstructive versus Reconstructive and Flow-Diverter Treatments

BACKGROUND AND PURPOSE

Various endovascular techniques have been applied to treat blister-like aneurysms. We performed a systematic review to evaluate endovascular treatment for ruptured blister-like aneurysms.

MATERIALS AND METHODS

We performed a comprehensive literature search and subgroup analyses to compare deconstructive versus reconstructive techniques and flow diversion versus other reconstructive options.

RESULTS

Thirty-one studies with 265 procedures for ruptured blister-like aneurysms were included. Endovascular treatment was associated with a 72.8% (95% CI, 64.2%-81.5%) mid- to long-term occlusion rate and a 19.3% (95% CI, 13.6%-25.1%) retreatment rate. Mid- to long-term neurologic outcome was good in 76.2% (95% CI, 68.9%-8.4%) of patients. Two hundred forty procedures (90.6%) were reconstructive techniques (coiling, stent-assisted coiling, overlapped stent placement, flow diversion) and 25 treatments (9.4%) were deconstructive. Deconstructive techniques had higher rates of initial complete occlusion than reconstructive techniques (77.3% versus 33.0%, P = .0003) but a higher risk for perioperative stroke (29.1% versus 5.0%, P = .04). There was no difference in good mid- to long-term neurologic outcome between groups, with 76.2% for the reconstructive group versus 79.9% for the deconstructive group (P = .30). Of 240 reconstructive procedures, 62 (25.8%) involved flow-diverter stents, with higher rates of mid- to long-term complete occlusion than other reconstructive techniques (90.8% versus 67.9%, P = .03) and a lower rate of retreatment (6.6% versus 30.7%, P < .0001).

CONCLUSIONS

Endovascular treatment of ruptured blister-like aneurysms is associated with high rates of complete occlusion and good mid- to long-term neurologic outcomes in most patients. Deconstructive techniques are associated with higher occlusion rates but a higher risk of perioperative ischemic stroke. In the reconstructive group, flow diversion carries a higher level of complete occlusion and similar clinical outcomes.

Endovascular management of intracranial blister aneurysms: spectrum and limitations of contemporary techniques

Background

Intracranial blister aneurysms are rare lesions that are notoriously more difficult to treat than typical saccular aneurysms. High complication rates associated with surgery have sparked considerable interest in endovascular techniques, though not well-studied, to treat blister aneurysms.

Objective

To evaluate our experience using various endovascular approaches to treat blister aneurysms.

Methods

All consecutive blister aneurysms treated using an endovascular approach by the study authors over a 3-year period were retrospectively analyzed. A literature review was also performed.

Results

Nine patients with blister aneurysms underwent 11 endovascular interventions. In various combinations, stents were used in 8/11, coils in 5/11, and Onyx in 3/11 procedures. At mean angiographic follow-up of 200 days, 8/9 aneurysms were completely occluded by endovascular means alone requiring no further treatment and 1/9 aneurysms required surgical bypass/trapping after one failed surgical and two failed endovascular treatments. At mean clinical follow-up of 416 days, modified Rankin Scale scores were improved in six patients, stable in two, and worsened in one patient. One complication occurred in 11 procedures (9%), resulting in a permanent neurologic deficit. No unintended endovascular parent vessel sacrifice, intraprocedural aneurysmal ruptures, antiplatelet-related complications, post-treatment aneurysmal re-ruptures, or deaths occurred.

Conclusion

This series highlights both the spectrum and limitations of endovascular techniques currently used to treat blister aneurysms, including a novel application of stent-assisted Onyx embolization. Long-term follow-up and experience in larger studies are required to better define the role of endovascular therapy in the management of these difficult lesions.

Blister-like aneurysms of middle cerebral artery: a multicenter retrospective review of diagnosis and treatment in three patients

Blood blister-like aneurysms (BBA) were described for the first time in the 1990s, as small hemispherical bulges arising from a very fragile arterial wall. Until 2008, it was thought that this type of aneurysm almost exclusively affected the internal carotid artery, in particular, its dorsal portion. Subsequently, it was discovered that a BBA may also be present on the anterior communicating artery and on the vessels of the posterior cranial fossa. However, we found no reports in English-language literature of BBA arising from the middle cerebral artery (MCA). In this article, we present three cases of MCA BBA and discuss the unique diagnostic and therapeutic aspects of this vascular lesion. In our retrospective, multicenter review of 1330 patients with non-traumatic subarachnoid hemorrhage admitted to our services from 2000 to 2013, we found three cases (all in men) of MCA BBA. The patients' outcome was assessed using the modified Rankin scale. All three patients underwent angio-computed tomography, which did not reveal any aneurysms. Digital subtraction angiography performed within 24-48 h after admission, in all cases, demonstrated a very small aneurysm (<2 mm), with a triangular shape and abroad base, at non-branching sites of MCA. All the aneurysms were treated: one by wrapping + clipping, one by wrapping + flow-diverter stent, and one with coils. At the time of surgery, the aneurysms appeared on the surface of the parent artery without any involvement of the branches. All presented as blister-like aneurysms that were thin-walled and lacked a surgical neck. At the time of discharge, the outcome was good in one patient and poor in the other two. Our cases demonstrate that BBA can also arise from the MCA, despite the lack of previous reports of this occurrence; a BBA should be suspected, particularly in cases of non-perimesencephalic subarachnoid hemorrhage in which the presence of a MCA aneurysm is suspected but not revealed by digital subtraction angiography or angio-computed tomography.

Endovascular internal carotid artery trapping for ruptured blood blister-like aneurysms: long-term results from a single centre

INTRODUCTION

Endovascular internal carotid artery (ICA) trapping was performed to treat ruptured blood blister-like aneurysms (BBAs). The aim of this study was to evaluate the procedural risks and long-term follow-up results.

METHODS

The records of 11 consecutive patients with BBAs who underwent endovascular ICA trapping between 2005 and 2010 were reviewed. Clinical outcomes were assessed with modified Rankin Scale (mRS) scores.

RESULTS

Endovascular ICA trapping was performed in 11 patients as either the primary treatment (7 patients) or the secondary treatment (4 patients) after the patient underwent other treatments. Three patients underwent superficial temporal artery (STA)-middle cerebral artery (MCA) bypass when balloon test occlusion (BTO) revealed inadequate collateral circulation. In the primary ICA trapping group (seven patients), six patients had good outcomes (mRS 0 in five, mRS 1 in one), and one patient had a poor outcome (mRS 6: dead). In the secondary ICA trapping group (four patients), two patients had good outcomes (mRS 0), and two patients had poor outcomes (mRS 4, 5). All ten of the surviving patients were clinically stable during the follow-up period (mean 39 months). A radiological follow-up of nine patients (mean 22 months) demonstrated stable occlusion, with the exception of one reopening of the ICA because of coil migration. Perfusion studies of nine patients (mean: 23 months) demonstrated no perfusion decrease.

CONCLUSION

Endovascular ICA trapping is an effective and durable treatment for BBAs.

Long-term Follow-up of Blister Aneurysms of the Internal Carotid Artery

BACKGROUND:

Blister aneurysms of the internal carotid artery (ICA) are uncommon. There is a paucity of data on the long-term outcomes of patients.

OBJECTIVE:

To review our experience with the treatment of these lesions.

METHODS:

We retrospectively reviewed all aneurysms treated at our institution between 1994 and 2005. Relevant operative notes, radiology reports, and inpatient/outpatient records were reviewed.

RESULTS:

Seventeen patients (3 male, 14 female) with 18 blister aneurysms of the ICA were identified. The mean age was 44.6 years (range, 17–72; median, 42 years). Twelve patients (70.6%) presented with aneurysmal subarachnoid hemorrhage. The mean admission Glasgow Outcome Scale score was 4.3 (range, 2–5; median, 5). All patients were initially treated using microsurgical technique with direct clipping (n = 15; 83.3%) or clip-wrapping with Gore-Tex (n = 3, 16.7%). There were 4 cases of intraoperative rupture, all associated with attempted direct clipping; all 4 cases were successfully clipped. Two cases rebled post-treatment. Both rebleeding episodes were managed with endovascular stenting. Follow-up angiography was available for 14 patients and revealed a new aneurysm adjacent to the site of clipping in 1 patient and in-stent stenosis in 2. At the mean follow-up of 74.5 months (median, 73; range, 7–165), the mean Glasgow Outcome Scale score was 4.6 (range, 2–5; median, 5).

CONCLUSION:

Microsurgical treatment of blister aneurysms of the ICA results in excellent outcome. In the evolution of treating these friable aneurysms, we have modified our clip-wrapping technique and use this technique when direct clipping is not feasible.