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

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.

Blood-Blister Aneurysms of the Internal Carotid Artery in Tibetan and Han Populations : A Retrospective Observational Study

OBJECTIVE

Blood-blister aneurysms (BBAs) of the internal carotid artery (ICA) are challenging lesions with high morbidity and mortality rates. Although research on BBAs is well documented in different populations, the study of BBAs in the Tibetan population is extremely rare. This study aimed to evaluate the characteristics of BBAs and analyze the treatment modalities and long-term outcomes in the Tibetan population in comparison with the Han population.

METHODS

The characteristics of patients with BBAs of the ICA from January 2009 to January 2021 at our institution were reviewed. The features of aneurysms, treatment modalities, complications, and follow-up outcomes were retrospectively analyzed.

RESULTS

A total of 130 patients (41 Tibetan and 89 Han patients) with BBAs of the ICA who underwent treatment were enrolled. Compared with the Han group, the Tibetan group significantly demonstrated a high ratio of BBAs among ICAs (8.6%, 41/477 vs. 1.6%, 89/5563; p<0.05), a high ratio of vasospasm (34.1%, 14/41 vs. 6.7%, 6/89; p=0.001), a high risk of ischemic events (43.9%, 18/41 vs. 22.5%, 20/89; p<0.05), and a low ratio of good outcomes (modified Rankin scale, 0-2) at the 1-year follow-up (51.2%, 21/41 vs. 74.2%, 66/89; p<0.05). The multivariate regression model showed that ischemic events significantly contributed to the prediction of outcomes at 1 year. Further analysis revealed that microsurgery and vasospasm were associated with ischemic events.

CONCLUSION

In comparison with Han patients, the Tibetan population had a high ratio of BBA occurrence, a high incidence of ischemic events, and a high ratio of poor outcomes. The endovascular approach showed more benefits in BBA patients.

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.

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.

Blister-like Cerebral Aneurysm after Endovascular Catheterization: A Case Report and Literature Review

Endovascular procedures have become a mainstay in the treatment of neurovascular pathologies like arteriovenous malformations and aneurysms. Catheter-induced blister-like aneurysms (BBAs) have not been described so far in the neurosurgical literature. The authors report a rare case of a possible, catheter-induced (iatrogenic) BBA of the supra-ventral wall of the internal carotid artery (ICA) post-endovascular coiling for posterior communicating artery (PComA) aneurysm and bring the rapid progression of BBA and the grade prognosis. A 46-year-old female presented with convulsions. Imaging studies showed diffuse subarachnoid haemorrhage (SAH) and a right saccular PComA aneurysm. Endovascular coiling of the aneurysm was performed, and it was uneventful. The patient had a good outcome (modified Rankin Scale of 1) with no neurological deficits and was discharged home on day five. However, on day nine after the first ictus, she experienced a severe headache at home and was rushed to the emergency room where she collapsed. A cranial computed tomography scan showed intracerebral haemorrhage with intraventricular extension and SAH. A cerebral angiogram showed a BBA of the supra-ventral wall of the ICA. A BBA needs to be considered as a complication of an endovascular procedure that may result in rapid neurological deterioration post-coiling due to rupture. The report also illustrates the rapid and catastrophic presentation of BBA.

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.

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.

Initial experience with Pipeline embolization of intracranial pseudoaneurysms in pediatric patients

OBJECTIVE

Flow-diverting devices have been used successfully for the treatment of complex intracranial vascular injuries in adults, but the role of these devices in treating iatrogenic and traumatic intracranial vascular injuries in children remains unclear. The authors present their experience using the Pipeline embolization device (PED) for treating intracranial pseudoaneurysms in children.

METHODS

This single-center retrospective cohort study included pediatric patients with traumatic and iatrogenic injuries to the intracranial vasculature that were treated with the PED between 2015 and 2021. Demographic data, indications for treatment, the number and sizes of PEDs used, follow-up imaging, and clinical outcomes were analyzed.

RESULTS

Six patients with a median age of 12 years (range 7-16 years) underwent PED placement to treat intracranial pseudoaneurysms. There were 3 patients with hemorrhagic presentation, 2 with ischemia, and 1 in whom a growing pseudoaneurysm was found on angiography. Injured vessels included the anterior cerebral artery (n = 2), the supraclinoid internal carotid artery (ICA, n = 2), the cavernous ICA (n = 1), and the distal cervical ICA (n = 1). All 6 pseudoaneurysms were successfully treated with PED deployment. One patient required re-treatment with a second PED within a week because of concern for a growing pseudoaneurysm. One patient experienced parent vessel occlusion without neurological sequelae.

CONCLUSIONS

Use of the PED is feasible for the management of iatrogenic and traumatic pseudoaneurysms of the intracranial vasculature in children, even in the setting of hemorrhagic presentation.

Coil Embolization with Subsequent Subacute Flow Diversion Before Hospital Discharge as a Treatment Paradigm for Ruptured Aneurysms

BACKGROUND

Subtotal coil embolization followed by subsequent flow diversion is often pursued for treatment of acutely ruptured aneurysms. Owing to the need for anti-platelet therapy, the optimal time of safely pursuing flow diversion treatment has not been fully elucidated. In this study, we aim to demonstrate the safety and feasibility of staged treatment of acutely ruptured aneurysms with early coil embolization followed by flow diversion prior to discharge.

METHODS

A retrospective study to evaluate clinical outcomes of patients who presented with aneurysmal subarachnoid hemorrhage and underwent coil embolization followed by subacute flow diversion treatment during the same hospitalization.

RESULTS

A total of 18 patients are included in our case series. Eight patients presented with Hunt-Hess (H-H) grade 2 bleed, 6 patients with H-H grade 3, and 2 patients each with H-H grade 4 and H-H grade 1. Eight patients required placement of an external ventricular drain on admission. After initial coil embolization, 12 achieved Raymond-Roy grade 2 occlusion, and 6 attained grade 3a/b occlusion. The mean duration between coil embolization and subsequent flow diversion was 9.83 days (range: 1-30). There were no instances of re-hemorrhage between initial coil embolization and subsequent flow diversion treatment. Sixteen patients had a minimum of 6-month follow-up, of which 15 were found to have complete occlusion, and 1 required subsequent clipping.

CONCLUSIONS

Subtotal coil embolization followed by definitive treatment using flow diversion during the same hospitalization is feasible and achieves excellent aneurysm occlusion rates while avoiding dual anti-platelet therapy during the initial hemorrhage period.

Treatment of an acutely ruptured complex fusiform middle cerebral artery aneurysm with flow diverting stenting and adjunctive coil embolization

This technical video demonstrates the treatment of an acutely ruptured, large, complex left fusiform middle cerebral artery (MCA) aneurysm with endovascular flow diversion with adjunctive coiling in a 27-year-old female. Two telescoping flow-diverting stents (Pipeline Flex) were placed, with partial coiling of a saccular portion of the aneurysm. Technical challenges, alternative treatment, intraoperative and postoperative antiplatelet management, vasospasm treatment, and clinical and radiographic follow-up are described. The video can be found here: https://stream.cadmore.media/r10.3171/2022.7.FOCVID2249.

Treatment of Blood Blister Aneurysms of the Internal Carotid Artery With Pipeline-Assisted Coil Embolization: A Single-Center Experience

Background

Blood blister aneurysm (BBA) is a complex and rare aneurysm that presents significant treatment challenges. The application of pipeline embolization device (PED)-assisted coiling in the treatment of ruptured BBA remains controversial. This study aimed to report on our experience and assess the safety and efficacy of this strategy.

Methods

Between February 2019 and February 2021, 12 patients with ruptured BBAs underwent PED-assisted coil embolization. We collected detailed data about each patient, including demographic information, aneurysmal data, technical details, antiplatelet strategy, operation-related complications, and follow-up outcomes.

Results

A total of 12 BBA patients were treated with single PED-assisted coil embolization. One patient experienced intraoperative rupture that was controlled by rapid coiling without clinical consequences. All the patients demonstrated complete occlusion on postoperative angiography. A total of three patients had postoperative complications: left hemiparesis, Broca's aphasia, and right hemiplegia due to vasospasm, and transient hemiparesis. Follow-up angiography revealed that all BBAs were completely occluded, except one with neck residue. All patients had favorable outcomes at discharge and the most recent clinical follow-up (mRS score ≤ 2).

Conclusion

Endovascular treatment of BBAs of the internal carotid artery using PED-assisted coil embolization is a safe and effective strategy. This has contributed to the understanding of BBA therapy and provides a potentially optimal treatment option for this intractable lesion.

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.

Flow diversion for acutely ruptured intracranial aneurysms treatment: A retrospective study and literature review

OBJECTIVE

Flow diversion is becoming an increasingly established practice for the treatment of acutely ruptured intracranial aneurysms. In this study the authors present a literature review and meta-analysis, adding a retrospective review of institutional registry on emergency treatment of aRIA with flow diverter stent.

MATERIALS AND METHODS

A systematic search of PubMed, SCOPUS, Ovid MEDLINE, and Ovid EMBASE was performed on April 20^th, 2021, extrapolating 35 articles. R language 'meta' and 'metafor' packages were used for data pooling. The DerSimonian-Laird model was used to calculate the pooled effect. The I² value and Q statistic evaluated study heterogeneity. Additionally, the authors retrospectively reviewed their institutional database for the treatment and outcomes of all patients with acutely ruptured intracranial aneurysms treated with flow diverter stent placement from May 2010 to November 2020 was performed.

RESULTS

From the systematic literature review and meta-analysis, the pooled proportion of complete aneurysm occlusion was 78%, with a pooled rate of 79%, 71%, 80%, and 50% for dissecting, saccular, fusiform, and mycotic aneurysms, respectively. The pooled proportion of aneurysm rebleeding and intrastent stenosis was 12% and 15% respectively, for a total of 27% rate. The analysis of authors retrospective register showed an overall mortality rate of 16.7% (3/18), with a low but not negligible postprocedural rebleeding and intrastent thrombosis rates (5.6% and 11.1% respectively).

CONCLUSION

Although increasingly utilized in the management of selected patients with acutely ruptured intracranial aneurysms, flow diversion for acutely ruptured intracranial aneurysms treatment presents rebleeding and intrastent stenosis rates not negligible.

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.

Microsurgical Clip Trapping of Dorsal Internal Carotid Artery Blister Ruptured Aneurysm: 2-Dimensional Operative Video

Dorsal internal carotid artery (ICA) blister aneurysms are an uncommon aneurysm variant constituting 0.3% to 1% of intracranial aneurysms and can be due to ulceration, atherosclerosis, or dissection.1-3 Despite its rarity, it carries a high risk of rupture with an estimation of 0.9% to 6.5% among intracranial aneurysms.1,2 Blister aneurysms are small in size, have no distinguishable neck, and have a friable wall that can easily rupture if manipulated, hence the difficulty in its treatment utilizing both microsurgical and endovascular techniques.1,2,4-6 Endovascular coiling of these lesions may not be adequate due to the broad-based size; stenting requires the use of antiplatelet medications, which could lead to rebleeding; flow diversion takes longer to exert its treatment effect.1,4 Conversely, microsurgical management carries a higher intraoperative rupture rate.2 Microsurgical options include clipping, clip reconstruction, trapping with bypass, and wrapping.4,7 We present a case of a 38-yr-old man who presented with a ruptured right dorsal ICA blister aneurysm treated with microsurgical trapping with intraoperative flow measurements. We demonstrate how the use of quantitative intraoperative flow measurements allows confident sacrifice of the supraclinoid ICA. We also demonstrate in contrast another case example of utilizing a clip-graft repair. The patient remained unchanged with an intact neurological exam, and postoperative imaging showed no aneurysm remnant and patent anterior choroidal artery. We review the literature and management of dorsal ICA aneurysms.8-15 We also review the technical nuances and different endovascular and microsurgical treatments that can be used for this condition.  The patient gave informed consent for the procedure and verbal consent to the publication.

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.

Internal Carotid Artery Blister Aneurysm: Review of Endovascular Techniques

Cerebral blister aneurysms are very difficult vascular lesions in terms of accurate diagnosis as well as proper management strategy for vascular neurosurgeons and neurointerventionists. Histopathological analysis has revealed their nature to be more akin to pseudoaneurysms in comparison to the typical berry aneurysms. This explains their fragile nature, with high probability of rerupture and regrowth during the follow-up if not addressed properly. Even though surgical approaches have evolved over the years to minimize intraprocedural rupture and recurrence, they still have relatively high morbidity as well as mortality in comparison to endovascular treatment. Over the last few years, endovascular treatment has evolved significantly, with introduction of new devices and techniques. Focus of the endovascular management has shifted from the deconstructive techniques to reconstructive ones with parent artery preservation. Recent introduction of flow diverter technology has enabled neurointerventionists to manage these difficult lesions with more confidence in terms of avoiding rerupture and recurrence. Flow diverter (FD) use in blister aneurysm resulted in high-technical success, complete aneurysm occlusion, and less complications in comparison to other reconstructive techniques like simple coiling, stent assisted coiling, and overlapping/monotherapy stent placement. Few debatable issues like use of dual antiplatelets in the setting of acute subarachnoid hemorrhage (SAH), timing of drugs in relation to procedures, single/overlapping devices, and concerns during cerebral vasospasm phase need further detailed analysis and standardized protocols. In this article, we have done a review of different endovascular treatment options in the management of internal carotid artery blister aneurysms with special focus on FD and issues related to it.

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%.

Endovascular Treatment Strategy and Clinical Outcomes for Ruptured Blood Blister-Like Aneurysms of the Internal Carotid Artery Using Low-Profile Visualized Intraluminal Support Stent

OBJECTIVE

It is challenging to safely treat blood blister-like aneurysms (BBAs) of the internal carotid artery. Endovascular surgery has been reported, but the optimal strategy is yet to be established. We report our endovascular treatment strategy using the Low-profile Visualized Intraluminal Support (LVIS) stent.

METHODS

Twelve patients with ruptured BBAs including 1 patient with 2 separate aneurysmal bulges were treated from December 2017 to January 2020. Single LVIS stent-assisted coil embolization was performed as the initial treatment. If the coil could not be placed in the aneurysm, or follow-up angiography showed persistent filling or regrowth of the aneurysm, a second LVIS stent was deployed as an overlapping stent. Clinical characteristics, treatment details, and clinical outcomes were retrospectively examined.

RESULTS

Single stent-assisted coiling was performed in 8 patients (69%), 2 overlapping stents with coiling in 1 (8%), a single stent in 2 (15%), and 2 overlapping stents in 2 (15%). Three patients with persistent filling or regrowth of the aneurysm were re-treated with overlapping stents. Follow-up angiography confirmed complete occlusion in 12 aneurysms (92%). No re-rupture occurred. Postoperative symptomatic ischemia was confirmed in 4 patients (33%), and all 4 patients suffered severe subarachnoid hemorrhage. Modified Rankin scale was 0-2 in 8 patients (67%).

CONCLUSIONS

LVIS stent-assisted coil embolization is effective in preventing re-rupture of BBAs. However, the morphology of the aneurysm may change within a short period, so careful angiographic follow-up is needed. Appropriate preoperative antiplatelet administration and optimal timing of the treatment may reduce the risk of postoperative ischemic complication.

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.

A Novel Parameter to Predict Supraclinoid Aneurysm Persistence After Flow Diversion with the Pipeline Embolization Device

BACKGROUND

Aneurysm recurrence after Pipeline Embolization Device (PED) placement can be caused by oversizing of the stent as well as poor wall apposition, both of which can lead to elongation. The objective of this study was to assess whether a novel parameter for measuring device elongation based on two-dimensional imaging could be predictive for persistent aneurysm filling after treatment with the PED.

METHODS

A retrospective cohort analysis was initially completed on 41 aneurysms from institution A, examining demographic, aneurysmal, and device measurements. Device measurements, including the ratio of the measured length to the nominal length (ML/NL) of the PED, were taken by reviewers blinded to the primary end point, which was aneurysm occlusion status on 6 month catheter angiogram. Findings were then externally validated against 30 aneurysms (supraclinoid only) from institution B.

RESULTS

Data from institution A showed 61% complete aneurysm occlusion at 6 months, and were lower for aneurysms in the supraclinoid region. For supraclinoid aneurysms alone, combined data from both institutions showed higher rates of nonocclusion with aneurysm neck size >4 mm (P = 0.008) and a trend toward significance in aneurysms with a branch vessel (P = 0.051). The mean ML/NL ratio was significantly larger in the nonoccluded group compared with the occluded group at both institution A (ratio, 1.37 versus 1.10; P < 0.001) and institution B (ratio, 1.36 vs. 1.11; P = 0.002).

CONCLUSIONS

Our data suggest that a novel parameter based on two-dimensional angiography may serve as a rapid technique to measure device elongation and predict occlusion of supraclinoid aneurysms after PED placement.

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.

Woven EndoBridge (WEB) device in the treatment of ruptured aneurysms

BACKGROUND

Wide-necked bifurcation aneurysms (WNBAs) present unique challenges for endovascular treatment. The Woven EndoBridge (WEB) device is an intrasaccular braided device, recently approved by the FDA for treatment of WNBAs. While treatment of intracranial aneurysms with the WEB device has been shown to yield an adequate occlusion rate of 85% at 1 year, few data have been published for patients with ruptured aneurysms.

OBJECTIVE

To present a multi-institutional series depicting the safety and efficacy of using the WEB device as the primary treatment modality in ruptured intracranial aneurysms.

METHODS

A multi-institutional retrospective analysis was conducted, assessing patients presenting with aneurysmal subarachnoid hemorrhage treated with the WEB between January 2014 and April 2020. Baseline demographics, aneurysm characteristics, adverse events, and long-term outcomes (occlusion, re-treatment, functional status) were collected. A descriptive analysis was performed, and variables potentially associated with aneurysm recurrence or re-treatment were assessed.

RESULTS

Forty-eight patients were included. Anterior communicating artery aneurysms were the most common (35.4%) location for treatment, followed by middle cerebral artery (20.8%) and basilar apex (16.7%). Procedural success was noted in 95.8% of patients, and clinically significant periprocedural adverse events occurred in 12.5%. After a median follow-up of 5.5 months, 54.2% of patients had follow-up angiographic imaging. Complete occlusion was seen in 61.5% of cases with adequate occlusion in 92.3%. Re-treatment was required in only 4.2% of patients during the study period. Tobacco use was significantly higher in patients with aneurysm recurrence (88.9% vs 35.7%; p=0.012). No other characteristics were associated with recurrence/re-treatment. At 30 days, 81.1% were functionally independent (modified Rankin Scale score ≤2).

CONCLUSION

Treatment of acutely ruptured aneurysms with the WEB device demonstrates both safety and efficacy on par with rates of conventional treatment strategies.

Experience With the Pipeline Embolization Device for Posterior Circulations Aneurysms: A Multicenter Cohort Study

BACKGROUND

The Pipeline Embolization Device (PED; Medtronic) has been used off-label for the treatment of challenging posterior circulation aneurysms. Data on this modality are primarily limited to small retrospective single-center series.

OBJECTIVE

To assess safety and efficacy of this treatment by establishing an international, multicenter collaboration.

METHODS

Consecutive posterior circulation aneurysms treated with the PED from 2012 to 2019 across 11 neurovascular centers were retrospectively reviewed. Baseline demographics, aneurysm and treatment characteristics, complications, occlusion status, and functional outcome were assessed.

RESULTS

There were 149 posterior circulation aneurysms treated with PED in 146 patients. A total of 24 (16.4%) patients presented with subarachnoid hemorrhage. Most aneurysms were dissecting/blister (36.2%) in morphology, followed by saccular (35.6%) and fusiform (28.2%). The most common locations were the vertebral (51.7%) and basilar arteries (22.8%). Complete or near-complete occlusion (>90%) was achieved in 90.9% of aneurysms at a median follow-up of 12 mo. Dissecting/blister aneurysms were most likely to occlude (P = .06). Symptomatic neurologic complications occurred in 9.4% of aneurysms, associated with larger size, ruptured presentation, presentations with brain stem compression, cranial nerve palsy, or stroke. Favorable functional outcome (modified Rankin Score 0-2) was achieved in 86.2% of patients. There were 6 fatalities of which 4 occurred in aneurysmal subarachnoid hemorrhage patients.

CONCLUSION

This multicenter study shows that PED for the treatment of posterior circulation is preferentially used for the treatment of fusiform and dissecting/blister aneurysm morphologies. Despite the challenges presented by these less-common morphologies, flow diversion may be performed with a neurologic complication rate of about 10% and favorable long-term aneurysm occlusion rates.

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.

Ruptured Basilar Artery Dissection Diagnosed Using Magnetic Resonance Vessel Wall Imaging and Treated with Coil Embolization with Overlapping LVIS Stents: A Case Report

The diagnosis and treatment of patients with ruptured basilar artery dissection (rBAD) are often difficult. We present a case of rBAD diagnosed with magnetic resonance vessel wall imaging (MR-VWI) and treated with coil embolization with overlapping low-profile visualized intraluminal support (LVIS) stents. The case is of a 49-year-old woman with subarachnoid hemorrhage. digital subtraction angiography (DSA) showed irregularity in an anterior wall of the middle portion of the basilar artery, indicating the presence of a false lumen. MR-VWI showed local enhancement in an arterial wall, which was consistent with the wall irregularity observed in DSA. Overlapping stents (two LVIS stents) was performed in the basilar artery and coils were placed in the false lumen. The false lumen was completely thrombosed, and anterograde blood flow of the basilar artery was preserved. Dual antiplatelet therapy was administered, and the patient underwent an uneventful postoperative course. DSA performed 6 months later showed a white-collar sign. MR-VWI has attracted attention as a useful modality for detecting a ruptured lesion in patients with subarachnoid hemorrhage. This is the first report, to the best of our knowledge, describing the practical use of MR-VWI for rBAD. MR-VWI is suggested to improve diagnostic accuracy for rBAD. There are no established treatments for rBAD; reconstructive endovascular treatments comprising stent placement and coil embolization of a false lumen are promising. The LVIS stent has a braided design and high metal coverage ratio and is considered to be reasonable for use in rBAD. Coil embolization of a false lumen with overlapping LVIS stents may be effective for rBAD.

Clinical utility and versatility of the petrous segment of the internal carotid artery in revascularization

Direct approaches to high cervical lesions, including tumors and aneurysms, carry significant risks. This renders alternative approaches desirable, with vascular disease amenable to exclusion and revascularization to the intracranial circulation, including the petrous or supraclinoid segments of the internal carotid artery (ICA). The cervicopetrous ICA bypass via saphenous venous grafting has proven an effective strategy for treating and excluding these lesions. In current practice, this is performed via an extradural subtemporal approach to access the petrous segment of the ICA and a cervical incision for access to the cervical ICA. The venous graft is alternately tunneled subcutaneously or in situ through the cervical ICA, with the latter eschewing external compression, kinking, and torsion, which increases risk of graft thrombosis with the former. Maxillary or middle meningeal arteries may also serve as donors to the petrous ICA. Moreover, the petrous ICA may be used as a donor in revascularization procedures, to the supraclinoid segment of the ICA and the middle cerebral artery, with petrous supraclinoid and petrous-MCA bypasses described. Clinical utility and operative approaches bypassing to or from the petrous ICA in revascularization procedures are reviewed and discussed.

Single-center experience with the new generation Derivo Embolization Device in ruptured dissecting and blister aneurysms

Background

Treatment of ruptured dissecting and blister aneurysms is technically challenging with potentially high morbidity and mortality. The Derivo Embolisation Device (Derivo) is a flow diverter stent designed for the treatment of intracranial aneurysms.

Purpose

To assess the safety and feasibility of the Derivo in the treatment of ruptured dissecting and blister aneurysms.

Material and Methods

We retrospectively analyzed all patients with ruptured dissecting and blister aneurysms treated with the Derivo between February 2016 and July 2018. Procedural details, complications, morbidity within 30 days, and angiographic aneurysm occlusion rates, initially and after six months, were assessed.

Results

In 10 patients 11 ruptured dissecting and blister aneurysms were treated with 12 Derivos as monotherapy. No aneurysm rebleeding was observed at follow-up. One treatment-related complication occurred including a coil perforation of an additionally treated aneurysm. One patient died due to brain edema. Initial digital subtraction angiography revealed complete (O’Kelly–Marotta [OKM] classification D) and favorable (OKM D+C) occlusion rate in three aneurysms. Six-month follow-up for digital subtraction angiography and clinical evaluation was available in 6/9 patients with complete (OKM D) occlusion in all aneurysms (6/6). Favorable (modified Rankin Scale [mRS] ≤ 2) and moderate (mRS 3) clinical outcome after a mean follow-up of 10 months was observed in six and two patients, respectively.

Conclusion

Endovascular treatment with the Derivo in ruptured dissecting and blister aneurysms revealed a sufficient initial division of aneurysms from the circulation without rebleeding. The Derivo is associated with high procedural and clinical short-term safety.

Expanding Indications for Flow Diverters: Ruptured Aneurysms, Blister Aneurysms, and Dissecting Aneurysms

BACKGROUND

The safety and efficacy of flow diversion (FD) in the treatment of cerebral aneurysms have been reported by many studies. FD has enabled the treatment of complex aneurysms and aneurysms that were previously untreatable by conventional means. It has achieved high rates of obliteration with essentially no recanalization, and its indications have continued to expand, now including ruptured aneurysms, blister aneurysms, and dissecting aneurysms.

OBJECTIVE

To provide a review on the outcomes of studies covering the use of FD in the settings of ruptured, blister, and dissecting aneurysms. In addition, to discuss dual antiplatelet therapy (DAPT) used in preparation for FD deployment in these scenarios, including associated complications with DAPT use in the acute rupture setting.

METHODS

References for this topical review were identified by PubMed searches between January 2000 and January 2019. The search terms “aneurysm”, “flow diverter”, “stent”, “pipeline”, “ruptured”, “blister”, and “dissecting aneurysms” were used.

RESULTS

FD carries a higher complication rate in the acute rupture setting than for unruptured aneurysms. Patient selection is of paramount importance for achieving good functional and angiographic outcomes. DAPT still remains challenging, especially in ruptured aneurysms. Advancements in surface modification of flow diverters can reduce the risk of thromboembolism and perhaps lead to a safer antiplatelet regimen.

CONCLUSION

In summary, FD shows promise to be an effective treatment for ruptured, blister, and dissecting aneurysms.

Flow Diversion for Intracranial Aneurysm Treatment: Trials Involving Flow Diverters and Long-Term Outcomes

Flow diverters (FDs) have changed the management of brain aneurysms; not only for complex aneurysms (giant, fusiform and blister) refractory to conventional therapies, but also for unruptured lesions previously managed by traditional surgical or coil-based endovascular methods. Since 2011 when the PipelineTM Embolization Device (Medtronic) was cleared by the Food and Drug Administration for adults with large or giant wide-neck intracranial aneurysms of the internal carotid artery proximal to the posterior communicating segment, the role of flow diversion for aneurysm treatment has expanded—supported by favorably low complication and high cure rates compared with alternative treatments. Here we review the key clinical trials and the long term outcomes that have demonstrated safety and efficacy of minimized porosity endoluminal devices in the treatment of cerebral aneurysms.

Flow diversion treatment for acutely ruptured aneurysms

Background and purpose

Flow diverters are sometimes used in the setting of acutely ruptured aneurysms. However, thromboembolic and hemorrhagic complications are feared and evidence regarding safety is limited. Therefore, in this multicenter study we evaluated complications, clinical, and angiographic outcomes of patients treated with a flow diverter for acutely ruptured aneurysms.

Methods

We conducted a retrospective observational study of 44 consecutive patients who underwent flow diverter treatment within 15 days after rupture of an intracranial aneurysm at six centers. The primary end point was good clinical outcome, defined as modified Rankin Scale score (mRS) 0–2. Secondary endpoints were procedure-related complications and complete aneurysm occlusion at follow-up.

Results

At follow-up (median 3.4 months) 20 patients (45%) had a good clinical outcome. In 20 patients (45%), 25 procedure-related complications occurred. These resulted in permanent neurologic deficits in 12 patients (27%). In 5 patients (11%) aneurysm re-rupture occurred. Eight patients died resulting in an all-cause mortality rate of 18%. Procedure-related complications were associated with a poor clinical outcome (mRS 3–6; OR 5.1(95% CI 1.0 to 24.9), p=0.04). Large aneurysms were prone to re-rupture with rebleed rates of 60% (3/5) vs 5% (2/39) (p=0.01) for aneurysms with a size ≥20 mm and <20 mm, respectively. Follow-up angiography in 29 patients (median 9.7 months) showed complete aneurysm occlusion in 27 (93%).

Conclusion

Flow diverter treatment of ruptured intracranial aneurysms was associated with high rates of procedure-related complications including aneurysm re-ruptures. Complications were associated with poor clinical outcome. In patients with available angiographic follow-up, a high occlusion rate was observed.

Endovascular treatment of intracranial 'blister' and dissecting aneurysms

INTRODUCTION

Blister and dissecting aneurysms may have a different pathological background but they are commonly defined by instability of the vessel wall and bear a high risk of fatal rupture and rerupture. Lack of aneurysm sack makes treatment challenging.

PURPOSE

The purpose of this study was to assess the safety and feasibility of endovascular treatment of intracranial blister and dissecting aneurysms.

METHODS

We retrospectively analysed all patients with ruptured and unruptured blister and dissecting aneurysms treated endovascularly between 2004-2018. Procedural details, complications, morbidity/mortality, clinical favourable outcome (modified Rankin Scale ≤2) and aneurysm occlusion rates were assessed.

RESULTS

Thirty-four patients with endovascular treatment of 35 aneurysms (26 dissecting aneurysms and 9 blister aneurysms) were included. Five aneurysms were treated by parent vessel occlusion, and 30 aneurysms were treated by vessel reconstruction using stent monotherapy (n = 9), stent-assisted coiling (n = 7), flow diverting stents (n = 13) and coiling + Onyx embolization (n = 1). No aneurysm rebleeding and no procedure-related major complications or deaths occurred. There were five deaths in consequence of initial subarachnoid haemorrhage. Complete occlusion (79.2%) was detected in 19/24 aneurysms available for angiographic follow-up, and aneurysm recurrence in 2/24 (8.3%). The modified Rankin Scale ≤2 rate at mean follow-up of 15.1 months was 64.7%.

CONCLUSION

Treatment of blister and dissecting aneurysms developed from coil embolization to flow diversion with multiple stents to the usage of flow diverting stents. Results using modern flow diverting stents encourage us to effectively treat this aneurysm entity endovascularly by vessel reconstruction. Therefore, we recommend preference of vessel reconstructive techniques to parent vessel occlusion.

Pipeline embolisation device with shield technology for the treatment of ruptured intracranial aneurysm

Flow diverters have emerged as a safe and effective treatment option for patients with complex unruptured cerebral aneurysms. Their utilisation in patients with ruptured aneurysms poses significant challenges, most notably the need for periprocedural dual antiplatelet medication. We describe the use of the pipeline embolisation device with shield technology in an 88-year-old patient with a complex ruptured posterior communicating artery aneurysm not amenable to microsurgical clipping or coiling alone. The pipeline embolisation device with shield technology utilises a phosphorylcholine coating to decrease thrombotic risk. We describe our antithrombotic protocol and technique to decrease the risk of acute re-rupture. The case highlights the option of using a flow diversion device with antithrombotic coatings in patients with complex ruptured cerebral aneurysms not amenable to coiling or microsurgical clipping.

Early Versus Delayed Flow Diversion for Ruptured Intracranial Aneurysms: A Meta-Analysis

OBJECTIVE

The use and timing of flow diversion for aneurysmal subarachnoid hemorrhage is controversial. The objective of this study is to perform a meta-analysis and systematic review to compare overall complication rate between early versus delayed flow diversion for ruptured aneurysms.

METHODS

A literature search for all eligible articles was performed using PubMed, Cochrane, and Web of Science databases. The primary outcome was the overall complication rate (any complication in the perioperative period), and secondary outcomes were 1) hemorrhage and 2) stroke/death (all hemorrhagic/ischemic strokes and/or death).

RESULTS

Thirteen articles including 142 patients met inclusion criteria. Eighty-nine (62.7%) patients underwent early deployment of flow diverters (i.e., 2 days or less). The odds ratio for overall complication rate with early versus delayed flow diversion was 0.95 (95% confidence interval [CI] 0.36-2.49, P = 0.42). The odds ratio for the secondary outcome of hemorrhagic complication for early versus delayed flow diversion was 1.44 (95% CI 0.45-4.52, P = 0.87) and of stroke/death was 1.67 (95% CI 0.5-4.9, P = 0.69). The odds ratio of early versus delayed flow diversion for blister/dissecting/fusiform aneurysms was 0.82 (95% CI 0.29-2.30) and for saccular/giant aneurysms was 2.23 (95% CI 0.17-29.4). At last follow-up, 71.6% of patients had good performance status (modified Rankin Scale score 0-2), and the rate of angiographic aneurysm occlusion was 90.2%.

CONCLUSIONS

This meta-analysis did not show a difference in overall complication rate between early versus delayed flow diversion for ruptured aneurysms. Early flow diversion for ruptured blister/fusiform/dissecting aneurysms carries a lower risk of aneurysm rerupture and overall complications as compared with that for ruptured saccular/giant aneurysms.

Treatment of posterior inferior cerebellar artery aneurysms using flow-diverter stents: A single-center experience

INTRODUCTION

The effectiveness and reliability of flow-diverter stents, which are commonly used in aneurysms of the anterior circulation, have been demonstrated previously. However, the use of these devices is associated with higher rates of perforator and branch ischemia following the treatment of aneurysms of the posterior circulation.

METHODS

This work involved a single-center; retrospective study reviewing eight patients who had aneurysms related to the posterior inferior cerebellar artery (PICA) and who were treated with flow-diverter stents from September 2013 to May 2017.

RESULTS

The mean aneurysm diameter was 7.6 mm (range, 5 to 11 mm). The types of aneurysm included five aneurysms that were saccular, two that were fusiform, and one that was dissecting. All saccular aneurysms in the neck involved the PICA origin, and one dissecting aneurysm was localized in the proximal part of the PICA. Procedural success was 100% (8/8), and there were no ischemic complications. One patient with subarachnoid hemorrhage died because of rebleeding (modified Rankin Scale (mRS), 6). Other than this patient all of the patients' mRS scores were zero at discharge and at the clinical follow-up period (mean, 2.5 years). All of the aneurysms were completely occluded according to the latest angiographic controls (mean follow-up period of 19.5 months).

CONCLUSIONS

Treatment of PICA aneurysms with flow-diverter stents showed positive results with a high rate of technical success and low complication and mortality rates. The use of flow-diverter stents in the treatment of PICA aneurysms should be considered a safe and effective endovascular treatment option.

Endovascular Metal Devices for the Treatment of Cerebrovascular Diseases

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

Microsurgical clipping and endovascular flow diversion of ruptured anterior circulation blood blister-like aneurysms

BACKGROUND

Detection and treatment of blister-like intracranial aneurysms as a source of subarachnoid hemorrhage (SAH) can be challenging. In the past the results of both microsurgical and endovascular treatment were difficult. We present our experience with the treatment of blister-like aneurysms in the acute phase of SAH using microsurgical clipping, endovascular parent vessel occlusion or flow diversion.

METHODS

A retrospective analysis of the cases of eight consecutive patients presenting in the acute phase after SAH from an intracranial blister aneurysm was performed. The demographic data of the patients, aneurysm characteristics, the clinical results of the treatment and the follow-up examinations were recorded. Procedural safety margins and aneurysm occlusion on follow-up digital subtraction angiography were the main interest of this evaluation.

RESULTS

Between January 2012 and November 2017 a total of eight ruptured blister aneurysms were treated in our center, six patients endovascularly. Five patients were treated in the acute phase of SAH, four by flow diversion. All endovascular procedures were feasible and no procedure-related complications were observed, especially no recurrent hemorrhage. In the first angiographic follow-up all blood blister-like aneurysms were completely occluded; two of the six patients treated by flow diverter implantation showed mild, transient intimal hyperplasia without clinical symptoms or the need for treatment.

CONCLUSIONS

Endovascular flow diversion is a viable option in the acute phase after SAH due to the rupture of a blister aneurysm. Implants with reduced thrombogenicity, obviating dual-platelet function inhibition, and flow diverters for vessel bifurcations would extend the indications for this treatment modality.

Acutely Ruptured Intracranial Aneurysms Treated with Flow-Diverter Stents: A Systematic Review and Meta-Analysis

BACKGROUND

The implantation of flow-diverter stents for the treatment of ruptured intracranial aneurysms required further investigation.

PURPOSE

Our aim was to analyze the outcomes after flow diversion of ruptured intracranial aneurysms.

DATA SOURCES

A systematic search of 3 databases was performed for studies published from 2006 to 2018.

STUDY SELECTION

According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we included studies (from 2010 to 2018) reporting acutely ruptured intracranial aneurysms treated with flow diversion.

DATA ANALYSIS

Random-effects meta-analysis was used to pool the following: aneurysm occlusion rate, complications, rebleeding, and factors influencing the studied outcomes.

DATA SYNTHESIS

We included 20 studies evaluating 223 patients with acutely ruptured intracranial aneurysms treated with flow-diverter stents. Immediate angiographic occlusion was obtained in 32% (29/86; 95% CI, 15.4%-48%; I² = 79.6%) of aneurysms, whereas long-term complete/near-complete aneurysm occlusion was 88.9% (162/189; 95% CI, 84%-93.5%; I² = 20.9%) (mean radiologic follow-up of 9.6 months). The treatment-related complication rate was 17.8% (42/223; 95% CI, 11%-24%; I² = 52.6%). Complications were higher in the posterior circulation (16/72 = 27%; 95% CI, 14%-40%; I² = 66% versus 18/149 = 11.7%; 95% CI, 7%-16%; I² = 0%) (P = .004) and after treatment with multiple stents (14/52 = 26%; 95% CI, 14%-45%; I² = 59%) compared with a single stent (20/141 = 10%; 95% CI, 5%-15%; I² = 0%) (P = .004). Aneurysm rebleeding after treatment was 4% (5/223; 95% CI, 1.8%-7%; I² = 0%) and was higher in the first 72 hours.

LIMITATIONS

Small and retrospective series.

CONCLUSIONS

Flow-diversion treatment of ruptured intracranial aneurysms yields a high rate of long-term angiographic occlusion with a relatively low rate of aneurysm rebleeding. However, treatment is associated with a complication rate of 18%. When coiling or microsurgical clipping are not feasible strategies, anterior circulation ruptured aneurysms can be effectively treated with a flow-diversion technique, minimizing the number of stents deployed. Given the 27% rate of complications, flow diversion for ruptured posterior circulation aneurysms should be considered only in selected cases not amenable to other treatments.

‘Plug and pipe’ strategy for treatment of ruptured intracranial aneurysms

Background

Aneurysmal subarachnoid hemorrhage is a potentially devastating condition, and among the first priorities of treatment is aneurysm occlusion to prevent re-hemorrhage. An emerging strategy to treat patients whose aneurysms are not ideal for surgical or endovascular treatment is subtotal coiling followed by flow diversion in the recovery phase or ‘plug and pipe’. However, data regarding the safety and efficacy of this strategy are lacking.

Methods

A retrospective cohort study was performed to evaluate the efficacy and safety of ‘plug and pipe’. All patients with a ruptured intracranial aneurysm intentionally, subtotally treated by coiling in the acute stage followed by flow diversion after recovery, were included. The primary outcome was re-hemorrhage. Secondary outcomes included aneurysm occlusion and functional status. Complications were reviewed.

Results

22 patients were included. No patient suffered a re-hemorrhage, either in the interval between coiling and flow diversion or in follow-up. The median interval between aneurysm rupture and flow diversion was 3.5 months. Roy–Raymond (R-R) class I or II occlusion was achieved in 91% of target aneurysms at the last imaging follow-up (15/22(68%) R-R 1 and 5/22(23%) R-R 2). Complications occurred in 2 (9%) patients, 1 of which was neurological.

Conclusions

Overall, these data suggest that subtotal coiling of ruptured intracranial aneurysms followed by planned flow diversion is both safe and effective. Patients who may most benefit from ‘plug and pipe’ are those with aneurysms that confer high operative risk and those whose severity of medical illness increases the risk of microsurgical clip ligation.

Stent and flow diverter assisted treatment of acutely ruptured brain aneurysms

OBJECTIVE

We present our experience with stent techniques in the management of acutely ruptured aneurysms, focusing on aneurysm occlusion rates, intraprocedural complications, and late outcomes.

METHODS

We retrospectively reviewed the clinical records of patients treated by stent techniques during the early acute phase of aneurysmal rupture, from June 2011 to June 2016. Patients who underwent stenting for the management of unruptured aneurysms, or in a delayed fashion for a ruptured lesion, were excluded.

RESULTS

47 patients met inclusion criteria, including 46 with subarachnoid hemorrhage (SAH). There were 27 men and 20 women, mean age 38 years (range 23-73). They harbored 71 aneurysms, including 56 treated in the acute phase. Aneurysmal dome and neck width averaged 4.7 mm (range 1.7-12.1) and 3.2 mm (range 1.5-7.1), respectively. Single stent techniques were used in 39 patients and dual stent techniques in 17. External ventricular drains (EVDs) were placed before embolization in 35 patients (92%) and after in 3. Intraprocedure thromboembolic complications due to a hyporesponse to antiplatlets in 4 patients (8.5%) were successfully managed with intra-arterial antiplatelet agents. In 45 surviving patients (96%), there was complete aneurysm occlusion at the 9-12 month follow-up in 26/29 aneurysms treated by stent-assisted coiling (90%), in 2/3 aneurysms treated by flow diverter-assisted coiling (66%), and in 19/22 aneurysms treated by flow diverter alone (86%); 42/45 patients (93%) presented with a modified Rankin Scale score of 0-2.

CONCLUSION

Stenting techniques in ruptured aneurysms can be performed with good technical success; however, procedural thromboembolic complications related to the antiplatelet strategy merit investigation. EVD placement before stenting must be considered.

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.

Evaluation of Enterprise Stent-Assisted Coiling and Telescoping Stent Technique as Treatment of Supraclinoid Blister Aneurysms of the Internal Carotid Artery

BACKGROUND

Supraclinoid blister aneurysms (BAs) of the internal carotid artery are uncommon and deadly, and appropriate treatment is controversial. Endovascular reconstruction may allow treatment through aneurysm isolation. We report a single-institution experience in the use of Enterprise stent-assisted coiling (ESAC) for treating BAs to appraise the safety and efficacy of this technique.

METHODS

Patients treated with ESAC for a BA at our institution between 2013 and 2016 were retrospectively included in this study. Patients' aneurysm characteristics, progression status, aneurysm occlusion on follow-up angiography, and modified Rankin Scale (mRS) score were recorded and analyzed. Occlusion rates and neurologic outcomes were compared between patients treated with a single stent and those treated with multiple telescoping stents.

RESULTS

Forty-four patients were included (17 males; average age, 47.3 years), and ESAC was successfully performed in all patients. Immediate postprocedure angiography revealed complete occlusion in 23 patients (52.3%), residual neck in 15 (34.1%), and residual aneurysm in 6 (13.6%). Twenty patients (45.5%) suffered perioperative cerebral vasospasm, and 3 (6.8%) died of secondary ischemic stroke. The duration of follow-up ranged from 2.5 to 27 months (mean, 11.59 ± 5.76 months). One patient with recurrence was treated with additional coiling, and another patient was treated with a covered stent. The use of telescoping stents was associated with a better complete aneurysm occlusion rate compared with the use of single stents (84.4% [27 of 34] vs. 44.4% [4 of 9]; P = 0.04). Follow-up mRS score was ≤1 for 32 of 41 patients (78.4%).

CONCLUSIONS

ESAC to treat BAs is safe, effective, and provides good clinical outcomes. ESAC with telescoping stents has a higher follow-up complete occlusion rate compared with ESAC with single stents.