Surgical management of blood blister-like aneurysms of the internal carotid artery

Computational hemodynamic pathophysiology of internal carotid artery blister aneurysms

OBJECTIVE

Blister aneurysms of the internal carotid artery (ICA) are rare and are primarily documented in the literature through small series and case reports. The intraoperative observation of a hemorrhage in the artery wall proximal to the aneurysmal bulge led to the hypothesis that some of these aneurysms might develop in a retrograde manner.

METHODS

We developed software to reconstruct the ICA with and without Type I and II blister aneurysms using patients' imagery as input to simulate hemodynamic conditions before and after their formation. Kinematic blood flow data before and after aneurysm formation were obtained using a finite volume solver. We compared the wall shear stress (WSS) distribution of the arterial wall prior to aneurysm formation.

RESULTS

In two out of four cases, WSS was significantly elevated on the dorsal wall of the supraclinoid segment of the ICA at the distal part of the future site of the aneurysm sac, suggesting that the aneurysm sac may ultimately develop in a retrograde fashion. Once the structural changes have been initiated, WSS gradient (WSSG) was significantly elevated at the proximal and distal boundaries of the bulging aneurysmal pouch. Low WSS and high WSSG at the proximal part of the aneurysm sac seem to contribute to the extension of the proximal intramural hematoma observed during blister aneurysm surgery.

CONCLUSIONS

By enabling assessment of the impact of elevated WSS and its gradient, our computational pipeline supports the hypothesis that the development of blister aneurysms may occur either in a retrograde or anterograde fashion.

Microsurgical treatment of blood blister-like aneurysms: efficacy of clip-on-wrapping with autologous dura mater

OBJECTIVE

To present a consecutive 20-year series of blood blister-like aneurysms (BBAs) to show that clip-on-wrapping with a Y-shaped autologous dura mater enables treatment of BBAs with a low complication rate and a satisfactory curative result.

METHODS

A retrospective review was performed from patients with BBAs of the internal carotid artery (ICA) at the Affiliated Hospital of Qingdao University from 1999 to 2019. Diagnosis and treatment options were analyzed. Outcome was assessed using the modified Rankin scale (mRS).

RESULTS

A total of 30 patients with BBAs of the ICA were included. Among these patients, 20 patients underwent microsurgical treatment (15 patients were treated by clip-on-wrapping with a Y-shaped autologous dura mater), the other 10 patients underwent endovascular treatment. All patients presented with subarachnoid hemorrhage (SAH). Four angiograms were initially negative. For all patients, intraoperative rupture occurred in five cases, but no postoperative aneurysm rupture occurred in this series. Three cases with clinical or radiologic cerebral infarctions were observed. The outcome was favorable in 26 patients.

CONCLUSIONS

Clip-reinforced wrapping technique using a Y-shaped autologous dura mater may be an effective method for treating BBAs.

Long-term follow up of surgical management of blood blister-like aneurysms at non-branching sites of the internal carotid artery

To describe long-term follow-up of 25 patients who presented with subarachnoid hemorrhages due to blood blister-like aneurysms (BBAs) treated with direct clipping or clip reinforcement with or without direct neck repair. Between June 1993 and July 2009, 25 consecutive patients with ruptured BBAs of the supraclinoid internal carotid artery were retrospectively reviewed. The mean age of patients was 39.5 ± 11.3 years. The mean duration of clinical follow-up was 128.9 months (range, 85-196 months). All aneurysms were located in the supraclinoid portion of the internal carotid artery. The mean aneurysm diameter was 4.04 ± 1.3 mm on intra-operative microscopic field. Tearing of the aneurysmal neck during dissection occurred in 8 (32%) patients. Six of 7 patients with neck tearing underwent direct neck repair. Surgeons treated aneurysms via direct clipping with a Bemsheet® in 5 (20%) patients or by clip reinforcement with a silicone sheet in 20 (80%) patients. Clinical outcomes were favorable (modified Rankin Scale [mRS]: 0-2) in 21 (84%) of 25 patients. Four (16%) patients had an unfavorable outcome (mRS: 3-6). The patient with severe disability (mRS: 4) was treated with clip reinforcement and direct neck repair. Mild stenosis, moderate stenosis, and total occlusion of the parent artery were confirmed in 10 (40%) patients, 6 (24%) patients, and 1 (4%) patient, respectively. Although surgical treatment of BBAs was associated with varying degrees of parent vessel patency loss, long-term follow-up results for more than 10 years showed that direct surgical clipping or clip reinforcement with a silicone sheet appeared to be a curative surgery.

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.

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.

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.

Surgical treatment of intracranial blister aneurysms: A systematic review

BACKGROUND

Intracranial blister aneurysms (BAs) are challenging vascular lesions related to high morbidity and mortality rates. Different surgical and endovascular techniques have been proposed to treat BAs; however, there is no consensus on a preferred treatment.

OBJECTIVE

To systematically review the pertinent literature on clinical and radiological outcomes of different surgical treatments for BAs management, to meta-analyze their clinical and radiological outcomes, and compare these results with those from recent meta-analyses on endovascular treatments for BAs.

METHODS

The present study was consistently conducted according to the PRISMA guidelines. Five different online medical databases (PubMed, Medline, EMBASE, Scopus, and Web-of-Science) were screened from 2010 through 2020. Papers reporting clinical and radiological outcomes of different surgical treatments for BAs were considered. Event rates were pooled across studies using random-effects meta-analysis.

RESULTS

A total of 35 studies reporting on 514 patients (534 aneurysms) were included. Aneurysm clipping in 223 patients (45.4%; 95% CI 21.9-53.8), bypass and trapping in 87 (17.7%; 95% CI 1.89-21.6), clipping and wrapping in 82 (16.7%; 95% CI 3.71-19.0), and wrapping in 33 (6.7%; 95% CI 0.0-4.87) were the mostly common performed treatments. Complete occlusion rate was reported in 90.7% of patients. The complication rate was as high as 61.1%, the mortality rate was 7.4%, and the mean mRS at follow-up was 2.5.

CONCLUSIONS

Our meta-analysis suggests that surgical treatments for BAs are related to higher occlusion, complications and mortality rate than endovascular strategies. However, there is a high-heterogeneity among the included studies and data are poorly reported; so comparing the two type of treatments is unreliable in order to establish which one is better.

Supraclinoid internal carotid artery blister-like aneurysms: hypothesized pathogenesis and microsurgical clipping outcomes

BACKGROUND

Blister-like aneurysms (BLAs) on the supraclinoid segment of the internal carotid artery (ICA) are an enigma of cerebrovascular disease. Neither has a definite pathogenesis been so far identified, nor have uniform treatment guidelines been established for them. Our aim was to develop a hypothesis regarding the evolution of BLAs according to their macroscopic morphologies and to evaluate the efficacy of microsurgical clipping.

METHODS

The clinical data and morphological features of 15 consecutive patients with 16 BLAs on the supraclinoid ICA were retrospectively reviewed. The treatment strategies were analyzed, and functional outcomes were evaluated using the modified Rankin scale (mRS). Favorable outcomes were defined as a mRS score of 0-2.

RESULTS

Morphologically, aneurysm growth with expansion of the aneurysm neck before the surgical procedure occurred in two ruptured and one unruptured aneurysm. Daughter bleb formation was observed in two ruptured and five unruptured aneurysms. A varied degree of parent artery sclerosis was observed in nine patients. Thirteen patients were treated with direct surgical clipping, one patient was treated with clipping and wrapping, and the remaining patient was treated with an encircling clipping graft. Favorable and unfavorable outcomes were observed in 13 and two cases, respectively. Follow-up angiograms revealed 4 cases of stenosis with respective degree of mild, 30%, 50%, and 80% without any neurological dysfunction.

CONCLUSIONS

We suggest a hypothesis that BLAs on the supraclinoid ICA may share different evolving mechanisms between ruptured and unruptured lesions. A majority of them can be reliably and safely obliterated by direct clipping technique, except for the aneurysms accompanied with severely atherosclerotic parent walls.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Endovascular Intervention with a Low-profile Visualized Intraluminal Support Stent Versus Surgical Clipping for Blood Blister-like Aneurysms : A Retrospective Study

PURPOSE

Blood blister-like aneurysms (BBAs) have a high risk of early recurrence and postoperative rebleeding. This study compared the clinical outcomes and complications between endovascular intervention with low-profile visualized intraluminal support (LVIS) stent-assisted coiling and the surgical clipping in patients with BBAs.

METHODS

This retrospective study enrolled 39 patients with BBAs who underwent endovascular intervention with LVIS stent-assisted coiling (n = 21) or surgical clipping (n = 18) between January 2013 and July 2018. Primary outcomes were mortality and modified Rankin scale (mRS). Secondary outcomes were hospital stay, intensive care unit (ICU) stay and operation parameters. Complications were also retrospectively collated.

RESULTS

At baseline, the two groups were well balanced in patient characteristics. The hospital stays, ICU stays, operation time and intraoperative infusion volume were all significantly lower in LVIS group than that in clipping group (p < 0.05). A second operation was performed in 6 cases in the clipping group but none in the LVIS group (p = 0.006). The mean mRS score in the LVIS group was significantly lower than that of the clipping group both at hospital discharge and final follow-up (p < 0.001). Adverse outcomes occurred in 1 case in LVIS group and 7 in clipping group, with significant difference (p = 0.015). Complications were reported in 8 cases in LVIS group and 16 cases in clipping group, with significant difference (p < 0.001).

CONCLUSION

The endovascular intervention with LVIS stent-assisted coiling has better prognosis than surgical clipping. It decreased the risk of a second operation and procedure-related complications compared with surgical clipping.

Concomitant ruptured anterior circulation and unruptured posterior circulation aneurysms: Treatment strategy and review of literature

Basilar artery apex or bifurcation is the most common location for aneurysms arising from posterior cerebral circulation. Reports of unruptured aneurysms of the basilar bifurcation associated with ruptured anterior circulation aneurysms are rare. The presence of multiple intracranial aneurysms poses a significantly high risk to management than a single aneurysm due several factors involved. Surgical management is considered the best treatment modality for most aneurysmal types and location with quite a few limitations when applicable. Authors have conducted a literature review of anterior and posterior circulation concomitant aneurysms and report their own experience with a case of anterior communicating artery blister type aneurysmal rupture presented with the symptoms and signs of subarachnoid hemorrhage concomitant with an unruptured basilar artery bifurcation aneurysm. Moreover, the anomalous origin of thalamoperforators at the basilar apex instead of the posterior cerebral artery makes it reasonably challenging for the microsurgical clipping. Discussed is the clinical presentation, radiological studies obtained, surgical approach utilized with an adequate exposure of the entire circle of Willis as well as the critical decision making when managing these challenging cases.

Blister aneurysms of the internal carotid artery: Surgical treatment and management outcome from a single center experience

OBJECTIVE

Blood-blister aneurysms (BBAs) of the internal carotid artery (ICA) are rare entities, but clinically important cause of subarachnoid hemorrhage (SAH). Several surgical and endovascular strategies have been attempted for these heterogeneous lesions. In this study, the authors analyzed the treatment strategy and outcomes in a series of cases of ICA blister aneurysms treated microsurgically.

PATIENTS AND METHODS

We retrospectively reviewed 15 consecutive cases of patients harboring ruptured BBAs, microsurgically treated at our institution between 2014 and 2018. We performed an analysis of the clinical and surgical aspects, as well as post-operative angiograms and outcomes.

RESULTS

Fifteen patients were identified; 9 (60%) were female. The mean age of presentation was 43,8 years. Most patients presented in good clinical conditions (Hunt-Hess 1-3 = 86%). The most common Fisher grade at presentation was 3 (60% of cases). All patients underwent digital subtraction angiography (DSA), revealing broad-based aneurysms at non-branching sites on the dorsal wall of the ICA. Intraoperatively, BBAs were confirmed in all cases. The lesions were approached through pterional (11-73%) or lateral supraorbital (4-27%) craniotomy. Direct clipping was performed in all but one lesion, in which case the clip-wrapping technique was used. Final angiographic control revealed complete occlusion in 14 cases. One patient required reoperation due to residual aneurysm filling. At discharge, a good outcome (Glasgow Outcome Scale [GOS] 4 or 5) was observed in 12 (80%) patients. Three patients were discharged with a GOS of 3.

CONCLUSION

Blood-blister-type aneurysms are rare and challenging lesions. Preoperative knowledge and careful surgical planning can prevent poor clinical outcomes. Surgical treatment remains an effective and safe option in this context.

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

Background

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

Methods

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

Results

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

Conclusions

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

Endovascular 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 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.

The unusual angiographic course of intracranial pseudoaneurysms

Although rare, traumatic intracranial pseudoaneurysms remain one of the most difficult vascular lesions to diagnose and treat. A 55-year-old male patient underwent endoscopic endonasal transphenoidal resection for a pituitary macroadenoma. The operation was complicated by an arterial bleed. The initial angiogram revealed pseudoaneurysm of the anterior choroidal artery. Although the pseudoaneurysm completely disappeared on the second angiogram, it was surprisingly found to have enlarged on the third angiogram. The lesion was successfully treated with flow-diversion using a pipeline embolization device. The present case demonstrates that the natural history of iatrogenic pseudoaneurysms may be unpredictable and misleading. Traumatic pseudoaneurysms should, therefore, be carefully followed when conservative treatment is elected or when the lesion seems to have spontaneously regressed. Flow-diversion seems to be a reasonable treatment option.

Morphological aspects of blister aneurysms and nuances for surgical treatment

OBJECT

Blister aneurysms of the supraclinoid part of the internal carotid artery (ICA) are known for their high morbidity and mortality rates related to treatment, regardless of whether the treatment is surgical or endovascular. However, this grim prognosis is based on results that indiscriminately group all blister aneurysms together without taking into account the heterogeneous appearance of these lesions. The goal of this study was 2-fold: to determine whether different blister aneurysm morphologies present different pitfalls, which would then require different surgical strategies, as well as to determine whether there are identifiable subgroups of these types of aneurysms based on morphology.

METHODS

The authors reviewed the charts, cerebral catheter angiograms, surgical reports, and intraoperative videos of all ICA blister aneurysms treated surgically at the Centre Hospitalier de l'Université de Montréal from 2005 to 2012 to investigate whether there was a relationship between morphology and pitfalls, and whether different surgical strategies had been used according to these pitfalls. During this review process the authors noted 4 distinct morphological aspects. These 4 aspects led to a review of the English and French literature on blister aneurysms in which imaging was available, to determine whether other cases could also be classified into the same 4 subgroups based on these morphological aspects.

RESULTS

The retrospective review of the authors' series of 10 patients allowed a division into 4 distinct subtypes: Type I (classic), Type II (berry-like), Type III (longitudinal), and Type IV (circumferential). These subtypes may at times be progressive stages in the arterial anomaly, and could represent a continuum. Each subtype described in this paper presented its own pitfalls and required specific surgical adaptations. Upon reviewing the literature the authors retained 35 studies involving a total of 61 cases of blister aneurysms, and all cases were able to be classified into 1 of these 4 distinct subtypes.

CONCLUSIONS

Although they share some common characteristics, blister aneurysms may be divided into distinct subtypes, suggestive of a continuum. Such a classification with a detailed description of each type of blister aneurysm would allow for better recognition to anticipate complications during intervention and better assess the different treatment strategies according to the subtypes.

Pipeline embolization for definitive endoluminal reconstruction of blister-type carotid aneurysms after clip wrapping

Background

Ruptured blister aneurysms of the carotid artery are difficult to safely treat. We present a novel strategy of microsurgical clip wrapping of internal carotid artery blister aneurysms in the setting of acute rupture, followed by delayed placement of a pipeline embolization device for definitive treatment.

Clinical presentation

We present two cases of ruptured blister aneurysms of the internal carotid artery treated by wrapping of the diseased segment of the vessel, followed by delayed deployment of a flow diverting stent once the patient was out of the vasospasm window but during the same hospitalization.

Results

Clip wrapping followed by flow diversion in a delayed fashion results in anatomic remodeling of the diseased artery without a high morbidity.

Conclusions

A combined approach of acute surgical stabilization followed by definitive endovascular reconstruction may reduce hemorrhagic complications while improving long term treatment durability.

Towards a new treatment paradigm for ruptured blood blister-like aneurysms of the internal carotid artery? A rapid systematic review

BACKGROUND AND PURPOSE

Owing to their peculiar features and rare occurrence, ruptured blood blister-like aneurysms (BBAs) of the internal carotid artery are challenging by both surgical and endovascular approaches and their proper management is uncertain. We therefore aimed to define the currently optimal treatment of ruptured BBAs in terms of mortality, outcome, rebleeding, and recurrence.

METHOD

An in-depth search of electronic databases, gray literature and internet resources for ruptured BBAs was performed and complemented by data retrieval during neurosurgical congresses. Clinical and radiological characteristics, intervention details, outcomes, and the impact factor of the source journal were pooled.

RESULTS

The pooled cohort comprised 311 patients. Neither surgical nor endovascular methods had an impact on clinical outcome, aneurysm regrowth, remote bleeding, or complication rate. By contrast, aneurysm clipping was a predictor of intraoperative bleeding (OR 6.5; 95% CI 1.2 to 34.3), and stent-assisted coiling increased the likelihood of a second treatment (OR 4.1; 95% CI 1.3 to 13.1), its conversion to another modality (OR 4.7; 95% CI 1.4 to 16.0), and incomplete aneurysm obliteration (OR 2.6; 95% CI 1.0 to 6.6). Higher impact journals were more likely to publish papers on endovascular techniques, particularly flow-diverter stents.

CONCLUSIONS

None of the methods is unequivocally superior. Considering its inefficiency, stent-assisted coiling should be undertaken with caution. A time-delimited systematic review is needed to establish the most accurate treatment for ruptured BBAs.

Endovascular treatment of supraclinoid internal carotid artery aneurysms

Endovascular management of intracranial aneurysms has advanced significantly over the last couple decades and continues to evolve, including aneurysms within the subgroup of supraclinoid internal carotid artery (ophthalmic, superior hypophyseal, posterior communicating, anterior choroidal, dorsal wall/blister, and carotid terminus).

Blood blister-like aneurysm with rupture point close to origin of anterior choroidal artery

If a ruptured blood blister-like aneurysm (BBA) arises from the lateral or superolateral wall of the internal carotid artery (ICA) at the level of the anterior choroidal artery (AChA), its proximity to the origin of the AChA presents a serious surgical challenge to preserve the patency of the AChA. Two such rare cases are presented, along with successful surgical techniques, including the application of a C-shaped aneurysm clip parallel to the ICA and a microsuture technique to repair the arterial defect. The patency of the AChA and ICA was successfully preserved without recurrence or rebleeding of the BBA during a 1-year follow-up after the operation.

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.

Stenting as monotherapy for uncoilable intracranial aneurysms

BACKGROUND

Small, blister-like aneurysms (BLAs), by virtue of their unique morphology, are difficult to treat with conventional modalities. The use of oversized self-expanding stents as monotherapy for BLAs is a relatively new and promising concept that warrants further investigation.

OBJECTIVE

To clarify the role of oversized self-expanding stents as monotherapy for BLAs.

METHODS

Five consecutive patients were treated for BLAs with oversized self-expanding stents alone by the senior author (K.R.B.). We report on their clinical and radiographic outcomes.

RESULTS

All 5 patients in our series were discharged in good clinical condition. Complete aneurysm occlusion was observed in all patients at the time of most recent radiographic follow-up. Mean follow-up time was 13.6 months (range, 1 month to 4.5 years).

CONCLUSION

The use of oversized self-expanding stents to redirect flow away from aneurysms is an effective option for patients with BLAs. This approach represents an alternative to the use of flow diverters.

Long-term clinical and angiographic outcomes of wrap-clipping strategies for unclippable cerebral aneurysms

PURPOSE

To evaluate the efficacy and stability of the wrap-clipping methods as a reconstructive strategy in the treatment of unclippable cerebral aneurysms.

MATERIALS AND METHODS

Twenty four patients who had undergone wrap-clipping microsurgery were retrospectively reviewed. Type and morphology of the treated aneurysm, utilized technique for wrap-clip procedure, and clinical outcome with angiographic results at their last follow-up were evaluated.

RESULTS

Of 24 patients, eleven patients had internal carotid artery (ICA) blister-like aneurysms, three had dissecting type aneurysms, and ten had fusiform aneurysms. The follow-up period for the late clinical and angiographic results ranged from 10 to 75 months (mean 35 months). Wrap-clipping was performed in eleven, wrap-holding clipping was in ten, and combination of wrap-clip and wrap-holding clip was in three cases. At the last angiographic follow-up study, twelve aneurysms (50%) were found to have completely healed, and nine aneurysms (38%) were at least stable. However, wrap-holding clip for the elongated blister type of ICA aneurysm was found failed, leading to fatal rebleeding in one case, and two cases of combination of wrap-clip-wrap-holding clip revealed delayed branch occlusion and marked regrowing, respectively.

CONCLUSION

Wrap-clipping strategy could be an easy and safe alternative for unclippable aneurysms. The wrapped aneurysm mostly disappeared, or at least remained stationary, after a long-term period. However, surgeons should be aware of that the wrapped aneurysm might become worse. Therefore, follow-up surveillance for an extended period should be mandatory.

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.

Blister-like aneurysms of the internal carotid artery - management considerations

Blood blister-like aneurysms (BBA) originate at non-branching sites of the internal carotid artery (ICA). These aneurysms present a fragile wall and a poorly defined broad-based neck. Recognition of the BBA is essential for proper management of these vascular lesions. Various surgical and endovascular strategies have been attempted for these heterogeneous lesions. These have been associated with significant morbidity and mortality including rebleeding, regrowth, ischemic and thromboembolic complications. The authors review the key elements important for diagnosis and management of BBA and review current treatment options.

Detection of blood blister-like aneurysm and intramural hematoma with high-resolution magnetic resonance imaging

Blood blister-like aneurysms (BBAs) tend to have a more precipitous clinical course, enlarging rapidly and rebleeding frequently. Nevertheless, they often present a diagnostic challenge because of the characteristic morphological features of a wide neck and shallow outpouching of the medial wall. The authors present the case of a 34-year-old woman who suffered a subarachnoid hemorrhage whose cause could not be determined on the initial imaging with digital subtraction (DS) angiography and CT angiography. Interestingly, MR imaging studies obtained on the 7th day revealed an intramural hematoma on the dorsal wall of the left internal carotid artery, which helped in the diagnosis of BBA on the third DS angiography study obtained on the 8th day, and in the surgical intervention on the 10th day. This case supports the hypothesis that focal dissection contributes to the formation of BBAs. Use of MR imaging in the subacute stage, in addition to DS and CT angiography, might be helpful in the diagnosis of BBAs.