Flow-diverting stent for ruptured intracranial dissecting aneurysm of vertebral artery

Evaluation of flow diverter use in acutely ruptured vertebral artery dissecting Aneurysms: A focus on safety and efficacy for rapid Aneurysm obliteration

OBJECTIVE

Flow diverter device (FDD) has emerged as the reconstruction technique for treating ruptured dissecting vertebral artery Aneurysms (VADA), but data on feasibility regarding re-rupture risk and timing of Aneurysm obliteration following FDD treatment is still limited. Therefore, this study aimed to evaluate the safety and efficacy of FDD in the treatment of VADAs presenting with subarachnoid hemorrhage (SAH).

METHODS

We retrospectively reviewed patients with ruptured VADA presenting with subarachnoid hemorrhage who underwent FDD placement at our institution between 2015 and 2023. Patient demographic data, Aneurysm configuration, and occlusion status were analyzed.

RESULTS

Thirteen patients with SAH from VADA rupture underwent FDD implantation. The average size of the largest diameter of the Aneurysm was 11.2 mm (range 6.5-21 mm). Eight of 13 (61.5 %) patients had their Aneurysms completely obliterated within 2 weeks after the procedure. The small dissecting Aneurysm (d = 0.636, p = 0.002) and degree of intra-Aneurysmal contrast stasis (d = 0.524, p = 0.026) were associated with rapid Aneurysm occlusion, according to the Somer's d coefficient. There were no ischemic or hemorrhagic complications at the average clinical follow-up of 28.4 months (range 5-67 months) and average angiographic follow-up of 20.1 months (range 3-60 months). A favorable outcome (mRS 0-2) was achieved in 12 patients (92.3 %).

CONCLUSIONS

FDD is safe and effective for the reconstruction of acutely ruptured VADAs. In addition, our study emphasizes that small dissecting Aneurysms tend to be rapidly obliterated after flow diversion, which eliminates the risk of re-rupture during the acute phase of subarachnoid hemorrhage.

Flow alteration surgery using a radial artery graft for recurrent ruptured vertebral artery dissecting aneurysm after stent-assisted coil embolization: A case report

BACKGROUND

Ruptured vertebral artery dissecting aneurysm (VADA) is often treated surgically with coil embolization and sometimes recurs. We herein report a case of recurrent ruptured VADA after stent-assisted coil embolization (SAC) that was successfully treated with flow alteration surgery using a radial artery (RA) graft.

CASE DESCRIPTION

A 67-year-old woman presented with headache and coma. Enhanced CT revealed subarachnoid hemorrhage due to right VADA. Since the left VA was hypoplastic, the aneurysm was treated with SAC. However, follow-up angiography revealed recurrence of the aneurysm. Additional embolization was not considered due to the small size of the recurrent lesion and the presence of a stent; therefore, flow alteration surgery was performed using a RA graft. There were no neurological deficits after surgery or recurrence.

CONCLUSION

Flow alteration surgery using a RA graft is useful for recurrent VADA after SAC.

Hemodynamic factors of spontaneous vertebral artery dissecting aneurysms assessed with numerical and deep learning algorithms: Role of blood pressure and asymmetry

BACKGROUND AND OBJECTIVES

The pathophysiology of spontaneous vertebral artery dissecting aneurysms (SVADA) is poorly understood. Our goal is to investigate the hemodynamic factors contributing to their formation using computational fluid dynamics (CFD) and deep learning algorithms.

METHODS

We have developed software that can use patient imagery as input to recreate the vertebrobasilar arterial system, both with and without SVADA, which we used in a series of three patients. To obtain the kinematic blood flow data before and after the aneurysm forms, we utilized numerical methods to solve the complex Navier-Stokes partial differential equations. This was accomplished through the application of a finite volume solver (OpenFoam/Helyx OS). Additionally, we trained a neural ordinary differential equation (NODE) to learn and replicate the dynamical streamlines obtained from the computational fluid dynamics (CFD) simulations.

RESULTS

In all three cases, we observed that the equilibrium of blood pressure distributions across the VAs, at a specific vertical level, accurately predicted the future SVADA location. In the two cases where there was a dominant VA, the dissection occurred on the dominant artery where blood pressure was lower compared to the contralateral side. The SVADA sac was characterized by reduced wall shear stress (WSS) and decreased velocity magnitude related to increased turbulence. The presence of a high WSS gradient at the boundary of the SVADA may explain its extension. Streamlines generated by CFD were learned with a neural ordinary differential equation (NODE) capable of capturing the system's dynamics to output meaningful predictions of the flow vector field upon aneurysm formation.

CONCLUSION

In our series, asymmetry in the vertebrobasilar blood pressure distributions at and proximal to the site of the future SVADA accurately predicted its location in all patients. Deep learning algorithms can be trained to model blood flow patterns within biological systems, offering an alternative to the computationally intensive CFD. This technology has the potential to find practical applications in clinical settings.

Efficacy and predicting factors of multimodal treatment for ruptured intracranial vertebral artery dissecting aneurysms

We aimed to investigate the efficacy of our multimodal strategies and propose a treatment algorithm for ruptured vertebral artery dissecting aneurysms (VADAs). This study included 41 patients treated at a single institution between 2015 and 2022. The treatment modalities were justified based on the collateral circulation and aneurysm location related to the posterior inferior cerebellar artery (PICA). Treatment outcomes and complications of each treatment group were analyzed. The association between the collateral blood flow and the postoperative vertebrobasilar ischemia (VBI) was also investigated. There were 17 post-PICA, 10 PICA-involved, 7 pre-PICA, and 7 non-PICA types. Reconstruction techniques included flow diversion devices (n = 11) and stent-assisted coiling (n = 3). Deconstruction techniques included coil trapping (n=17) and microsurgical parent artery occlusion with (n = 8) or without PICA revascularization (n = 2). Five (18.5%) of the deconstruction group had postoperative VBI. Overall favorable outcomes in both groups were observed in 70.7% of patients with a mean follow-up time of 21.5 months. Poor World Federation of Neurosurgical Societies grade (IV-V) was identified as a predictor of unfavorable outcomes (p = 0.003). In addition, the VA4/BA4 ratio > 0.22, the presence of collateral blood flow from the posterior communicating artery (PcomA), and a contralateral VA diameter > 2.5 mm were associated with a lower risk of postoperative VBI. In summary, the proposed strategic treatment in this study is pragmatic, yielding satisfactory results where a deconstructive technique should be used with caution, particularly when there is a flow mismatch or the absence of collateral PcomA in the vertebrobasilar circulation.

Flow Diverter in Unruptured Intracranial Vertebral Artery Dissecting Aneurysm

Objective

Intracranial vertebral artery dissecting aneurysm (VADA) may present as aneurysmal dilation alone, dilation with coexisting stenosis, or, in some cases, as a recurrent aneurysm after previous reconstructive treatment. To date, the clinical utility of flow diverters in VADA has not been examined according to these various circumstances. This study aims to report the safety and efficacy of flow diverters in the treatment of various manifestations of intracranial VADA.

Methods

A total of 26 patients and 27 VADAs treated with flow diverting stents from November 2014 to September 2021 were included. Medical records and radiologic data were analyzed to assess the safety and efficacy of flow diverting stents.

Results

The results showed that 12 cases (44.4%) presented with aneurysmal dilation only, 7 (26.0%) with aneurysmal dilation and one or more associated stenotic lesions, and 8 (29.6%) as recurrence after previous treatment, including stent-assisted coil embolization (n = 5), single stent only (n = 1), and coil embolization without stent (n = 2). Among 27 lesions, 25 were treated with single flow diverters; additional flow diverting stents were required in 2 cases because of incomplete coverage of the aneurysm neck. There was one instance of incomplete expansion of the flow diverter. All cases showed contrast stagnation in the aneurysmal sac immediately after deployment of the flow diverting stent, and during a mean follow-up period of 18.6 months (range 6 to 60), the overall complete occlusion rate was 55.6%, with complete occlusion of 83.3% of aneurysmal dilation only lesions, 42.9% of aneurysms with stenosis, and 25% of the recurrent aneurysm. Only two patients (7.7%) had delayed ischemic complications.

Conclusion

Flow diverters have proven safe and effective in unruptured VADA. However, the complete occlusion rate with the flow diverter is relatively lower in VADA with stenosis or with previous stent placement than in dilation-only lesions. Further study with a larger cohort would be needed to confirm these results.

Diagnostic Performance of High-Resolution Vessel Wall Magnetic Resonance Imaging and Digital Subtraction Angiography in Intracranial Vertebral Artery Dissection

Purpose: Intracranial vertebral artery dissection (VAD) is being increasingly recognized as a leading cause of Wallenberg syndrome and subarachnoid hemorrhage. Conventional angiography is considered the standard diagnostic modality, but the diagnosis of VAD remains challenging. This study aimed to compare the diagnostic performance of high-resolution vessel wall imaging (HR-VWI) with digital subtraction angiography (DSA) for intracranial VAD. Materials and methods: Twenty-four patients with 27 VADs, who underwent both HR-VWI and DSA within 2 weeks, were consecutively enrolled in the study from March 2016 to September 2020. HR-VWI and DSA were performed to diagnose VAD and to categorize its angiographic features as either definite dissection or suspicious dissection. Features of HR-VWI were used to evaluate direct arterial wall imaging. The reference standard was set from the clinicoradiologic diagnosis. Two independent raters evaluated the angiographic features, dissection signs, and interrater agreement. Each subject was also dichotomized into two groups (suspicious or definite VAD) in each modality, and diagnosis from HR-VWI and DSA was compared with the final diagnosis by consensus. Results: HR-VWI had higher agreement (90.6% vs. 53.1%) with the final diagnosis and better interrater reliability (kappa value (κ) = 0.91; 95% confidence interval (CI) = 0.64–1.00) compared with DSA (κ = 0.58; 95% CI = 0.35–1.00). HR-VWI provided a more detailed identification of dissection signs (77.7% vs. 22.2%) and better reliability (κ = 0.88; 95% CI = 0.58–1.00 vs. κ = 0.75; 95% CI = 0.36–1.00), compared to DSA. HR-VWI was comparable to DSA for the depiction of angiographic features for VAD. Conclusions: HR-VWI may be useful to evaluate VAD, with better diagnostic confidence compared to DSA.

Subarachnoid Hemorrhage Due to Rupture of Vertebral Artery Dissecting Aneurysms: Treatments, Outcomes, and Prognostic Factors

BACKGROUND

Mortality rate after subarachnoid hemorrhage due to rupture of vertebral artery dissecting aneurysms (VADAs) is high; endovascular coil trapping is the first-line therapy to prevent rerupture. To select optimal treatments, the positional relationship between the VADA and posterior inferior cerebellar artery (PICA) and the morphology of the contralateral vertebral artery must be considered, and outcome predictors of different treatment methods and their possible complications must be identified.

METHODS

We retrospectively studied 44 patients with ruptured VADAs who had undergone endovascular or surgical treatment. VADA morphology was assessed on conventional preoperative angiograms, and VADAs were categorized based on their site in relation to the PICA. VADA site, treatment method, and complications were used to identify prognostic factors.

RESULTS

The sites of the 44 VADAs were PICA-proximal (n = 3), PICA-distal (n = 22), PICA-absent (n = 7), and PICA-involved (n = 12). Treatments included internal coil trapping (n = 30), proximal coil occlusion (n = 5), and stent placement (n = 3); surgical flow alteration via an occipital artery-PICA bypass and ligation at the proximal vertebral artery and the PICA origin was performed in 6 patients. Periprocedural rebleeding was associated with a poor outcome. Internal coil trapping prevented the rerupture of PICA-proximal and PICA-absent VADAs, and flow alteration prevented rerupture of PICA-involved VADAs; there were no complications directly attributable to these procedures.

CONCLUSIONS

Periprocedural rebleeding was a poor prognostic factor. Internal trapping of PICA-proximal and PICA-absent VADAs and flow alteration in PICA-involved VADAs prevented rerupture.

Endovascular treatment of vertebral artery dissecting aneurysms : a 20-year institutional experience

BACKGROUND

The ideal treatment for unruptured vertebral artery dissecting aneurysms (VADAs) and ruptured dominant VADAs remains controversial. We report our experience in the management and endovascular treatment of patients with VADAs.

METHODS

Patients treated endovascularly for intradural VADAs at a single institution from January 1, 1999, to December 31, 2019, were retrospectively reviewed. Primary neurological outcomes were assessed using modified Rankin Scale (mRS) scores, with mRS >2 considered a poor neurological outcome. Additionally, any worsening (increase) in the mRS score from the preoperative neurological examination was considered a poor outcome.

RESULTS

Ninety-one patients of mean (SD) age 53 (11.6) years (48 (53%) men) underwent endovascular treatment for VADAs. Fifty-four patients (59%) presented with ruptured VADAs and 44 VADAs (48%) involved the dominant vertebral artery. Forty-seven patients (51%) were treated with vessel sacrifice of the parent artery, 29 (32%) with flow diversion devices (FDDs), and 15 (17%) with stent-assisted coil embolization (stent/coil). Rates of procedural complications and retreatment were significantly higher with stent/coil treatment (complications 4/15; retreatment 6/15) than with vessel sacrifice (complications 1/47; retreatment 2/47) or FDD (complications 2/29; retreatment 4/29) (p=0.008 and p=0.002, respectively). Of 37 patients with unruptured VADAs treated, only two (5%) had mRS scores >2 on follow-up.

CONCLUSION

Endovascular FDD treatment of VADAs appears to be associated with lower retreatment and complication rates than stenting/coiling, although further study is required for confirmation. Endovascular treatment of unruptured VADAs was safe and was associated with favorable angiographic and neurological outcomes.

Treatment of pediatric intracranial dissecting aneurysm with clipping and angioplasty, and next-generation sequencing analysis: A case report and literature review

BACKGROUND

Large intracranial dissecting aneurysm (IDA) in the anterior cerebral circulation is rare in children. There has been no consensus on the diagnosis and treatment for IDA in children.

CASE SUMMARY

We report a 3-year-old boy with a large ruptured IDA in the right middle cerebral artery (16 mm × 14 mm). The IDA was successfully managed with clipping and angioplasty. Next-generation sequencing of the blood sample followed by bioinformatics analysis suggested that the rs78977446 variant of the ADAMTS13 gene is a risk for pediatric IDA. Three years after surgery, the boy was develop-mentally normal.

CONCLUSION

Clipping and angioplasty are effective treatments for ruptured IDA in the anterior cerebral circulation. ADAMTS13 rs78977446 is a risk factor for pediatric IDA.

Endovascular Treatment of Intracranial Vertebral Artery Dissection

Intracranial vertebral artery dissection (VAD) is the most common arterial dissection in intracranial arteries. Some types of VAD can heal spontaneously after reconstitution of the vessel lumen with excellent prognosis, whereas others can progress to stroke that needs treatment. Recently, endovascular treatment (EVT) has emerged and is suggested as a treatment option for VADs due to perceived low rates of procedure-related morbidity with good efficacy. In the last decade, we have accumulated our strategies to treat those VADs. Here, we try to share our experiences about VADs, including indications and methods of treatment of VADs using EVT. We perform EVT for ruptured VADs presenting with SAH and some of unruptured VADs such as VAD with recurrent or progressive ischemia, dissecting aneurysm larger than 7 mm or with mass effect, early ugly change of VADs in shape and size during follow-up period, involving the basilar artery (BA) and bilateral VADs. We present how we have done in our real practice for the last decade for treating VADs by EVT rather than reviewing and organizing so-far-published literature. We tended to occlude the rupture point by vertebral artery (VA) occlusion in non-dominant VA or stent-assisted coiling in dominant VA for ruptured VADs. We tended to reconstruct original hemodynamics using various stents for unruptured VADs. To decide what to treat and how to treat are very complicated for VADs. However, we believe that EVT is the current mainstay for treating VADs. Each technique of EVT should be determined on a case-by-case basis at the discretion of endovascular neurosurgeons and/or interventional neuroradiologists according to presenting symptoms, hemodynamic status, including sufficiency of the collateral supply and anatomic features of the vertebrobasilar artery as well as the posterior inferior cerebellar artery, anterior spinal artery, and medullary perforators.

Delineability and anatomical variations of perforating arteries from normal vertebral artery on 3D DSA: implications for endovascular treatment of dissecting aneurysms

BACKGROUND AND PURPOSE

Endovascular trapping of the vertebral artery dissecting aneurysms (VADAs) carries a risk of medullary infarction due to the occlusion of the perforating arteries. We evaluated the detectability and anatomical variations of perforating arteries arising from the vertebral artery (VA) using three-dimensional DSA.

METHODS

In 120 patients without VA lesions who underwent rotational vertebral arteriography, the anatomical configurations of perforating arteries from the VA were retrospectively evaluated on the bi-plane DSA and reconstructed images to reach the consensus between two experienced reviewers. The images were interpreted by focusing on the numbers and types of perforating arteries, the relationships between the number of perforators and the anatomy of the VA and its branches.

RESULTS

Zero, 1, 2, 3, 4, and 6 perforators were detected in 2, 51, 56, 9, 1, and 1 patient, respectively (median of 2 perforators per VA). The 200 perforators were classified into 146 terminal and 54 longitudinal course types and into 32 ventral, 151 lateral, and 17 dorsolateral distribution types. All ventral type perforators were also terminal type. In contrast, the longitudinal type was seen in 28.5% of lateral types and in 65% of dorsolateral types. Regarding the difference in the origin of the posterior inferior cerebellar artery (PICA), non-PICA type VAs gave off larger number of perforators than the other types of VAs.

CONCLUSIONS

Non-PICA type VAs give off a significantly larger number of perforators than other types, indicating that the trapping of non-PICA type VAs is associated with a risk of ischemic complications.

Endovascular Management of Intracranial Vertebral Artery Dissection: Technical Nuances for the Preservation of Posterior Inferior Cerebellar Artery and Basilar Artery

BACKGROUND

The treatment of intracranial vertebral artery dissection (VAD) can be challenging.

OBJECTIVE

To evaluate the clinical presentation, endovascular treatment techniques, and prognostic outcome of patients diagnosed with intracranial VAD at our institution.

METHODS

A retrospective analysis of 35 patients who were diagnosed with VAD at our institution over 17-yr period (2001-2017) is presented. A total of 27 patients with a total of 30 affected arteries underwent endovascular treatment, and their outcome was evaluated.

RESULTS

Of the 35 total patients with VAD, 15 presented with headache, 12 with focal neurological deficits, 2 with neck pain, 2 with dizziness, 1 with syncope, and 3 after trauma. Of the 30 dissected arteries, 18 were treated with deconstruction and 12 were treated with stent reconstruction. Treatment method was determined by the dominance of the affected artery and location relative to the ipsilateral posterior inferior cerebellar artery (PICA) and the basilar artery. Deconstructive techniques were utilized in all cases of hypoplastic artery dissection and the majority of codominant artery dissections, whereas reconstruction was performed on the majority of dominant artery dissections. Rupture did not impact treatment technique. Four patients demonstrated post-treatment infarcts, and another 1 patient died because of intraparenchymal bleed. The remaining 22 patients demonstrated favorable clinical outcome. None of the patients developed recanalization or needed retreatment till the last follow-up.

CONCLUSION

This study suggests that endovascular treatment of intracranial VAD with deconstruction or stent reconstruction based on the patients anatomy, particularly vessel dominance and location with respect to PICA, is feasible and effective though the revascularization procedures still has its role in selected cases.

Reconstructive treatment of symptomatic vertebral artery dissecting aneurysms with Willis covered stent: Initial experience

Background

Symptomatic vertebral artery dissecting aneurysm (VADA) is a challenging disease with controversy on treatment strategy due to anatomic configuration and their nature. Moreover, the outcomes of reconstructive treatment have not been well established.

Objective

To evaluate the safety and efficacy of reconstructive endovascular treatment (EVT) for symptomatic VADAs with Willis covered stent.

Methods

We evaluated retrospectively 13 patients with symptomatic VADAs who treated with Willis covered stent, compared with stent-assisted coiling (SAC) on the characteristics, posttreatment course, angiographic and clinical follow-up outcomes at an average of 14.4 months (range, 3–48 months).

Results

A total of 33 patients with symptomatic VADAs were reviewed, 23 of these patients with ruptured VADAs. The technical successful rate is 100% respectively in Willis covered stent (Group A) and SAC (Group B, n ​= ​20). The initial complete occlusion rate was significant higher in group A (100%) than group B (30%) (p ​< ​0.01). Major procedure-related complications were not significant different in the two groups. Serial follow-up angiograms revealed 5 recurrent VADAs in group B and no recurrence in group A (p ​> ​0.05). No obvious in-stent stenosis and no re-hemorrhage and delayed ischemic symptoms during the follow-up period. The final angiograms of all survived patients demonstrated the complete occlusion rate was higher in group A (100%) than group B (80%), but no significant statistical difference (p ​> ​0.05). Clinical outcomes were favorable in 31 (93.9%), severe disability occurred in one in group B, and only one death in group A. The final clinical outcomes were also not significant difference in the two groups (p ​> ​0.05).

Conclusions

Our initial result demonstrated reconstructive EVT with Willis covered stent provides a viable approach for selected symptomatic VADAs involving the intracranial and extracranial segments, which is similar to favorable results with SAC. However, an expanded clinical experiences and larger cohort studies are needed.

Rerupture Following Flow Diversion of a Dissecting Aneurysm of the Vertebral Artery: Case Report and Review of the Literature

BACKGROUND

Dissecting aneurysms of the posterior cerebral circulation can wield significant treatment challenges with devastating clinical outcomes. Despite an expanded therapeutic armamentarium, these vascular lesions remain relatively difficult to diagnose and portend high associated morbidity and mortality.

METHODS

A ruptured, fusiform, dissecting aneurysm of the mid V4 segment of the right vertebral artery (VA) distal to the posterior inferior cerebellar artery origin resulted in a Hunt and Hess grade 5, Fisher scale score 4 subarachnoid hemorrhage. The lesion incorporated 360 degrees of the vessel wall and extended across an area measuring 11 mm in length and 6.8 mm in width at maximum dimension. The vascular lesion was treated with 2 overlapping Pipeline Embolization Devices.

RESULTS

Digital subtraction angiography demonstrated an origin of the right posterior inferior cerebellar artery mildly stenosed by the dissecting aneurysm. The left VA was markedly hypoplastic. After deployment of 2 overlapping Pipeline Embolization Devices, the aneurysm neck was well covered with appropriate positioning of the stent construct with good apposition to the vessel wall. There was contrast stasis within the aneurysm. The patient was managed with dual antiplatelet therapy. He demonstrated initial clinical and radiographic improvement. However, on the night of the second postprocedure day, the patient succumbed to rerupture of the aneurysm.

CONCLUSIONS

The literature posits that nonsaccular, fusiform, and dissecting aneurysms of the vertebrobasilar circulation can be occluded with consistency and success using flow diversion techniques. Endovascular treatment of a ruptured dissecting aneurysm of the VA is technically feasible and can be performed with or without parent artery occlusion. Outcomes following flow diversion of the posterior circulation may depend on the location of the dissection and viability of collateral circulation. In the present case, adequate coverage of the aneurysm did not portend a positive outcome.

A Case of Brainstem Infarction That Was Found to Be Vertebral Artery Dissection in a Short Period after the Diagnosis of Atherothrombotic Infarction

Objective

We report a case of vertebral artery dissecting aneurysm that caused right lateral medullary infarction, which was treated by endovascular therapy.

Case Presentations

A 57-year-old man developed right-side headache and dysarthria on the day before presentation, and exhibited mouth dropping and dysphagia the following day. Initial MRI demonstrated right lateral medullary infarction with atherothrombotic change with no vessel lesion, and we started infusion and medication administration. Later MRI revealed bilateral vertebral artery dissection, and we treated the growing right vertebral artery dissecting aneurysm by stenting and coils.

Conclusion

The possibility of dissecting lesions should be considered in cases of medullary infarction. Stenting and coil treatment is a useful option for bilateral dissecting vertebral aneurysms.

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.

First clinical experience with the new Surpass Evolve flow diverter: technical and clinical considerations

Objective

To describe the results in patients treated with the Surpass Evolve (SE) device, the new generation of Surpass flow diverters.

Methods

Twenty-five consecutive patients (20 women, average age 58 years), with anterior or posterior circulation aneurysms treated with SEs in two early-user centers, were included. Device properties and related technical properties, imaging and clinical follow-up data, and intraprocedural, early (<30 days) and delayed (>30 days) neurological complications, further divided into minor (silent/non-permanent) and major (permanent) complications, were recorded and analyzed.

Results

Twenty-nine SEs were successfully implanted in all subjects to treat 26 aneurysms using an 0.027" microcatheter with an average of 1.2 stents per patient. No intraprocedural thromboembolic or hemorrhagic complications were seen. At clinical follow-up, 24/25 (96%) patients had a modified Rankin Score of 0–2. Mortality was 0%. Imaging follow-up, available in 22/25 (88%) patients (median follow-up time 4 months), showed a complete aneurysm occlusion in 13/23 (57%) imaged lesions. Minor, transitory neurological deficits were recorded in 5/25 (20%) patients. One (4%) major complication was seen in one patient (4%) with a left-sided hemispheric stroke on postprocedural day 4 due to an acute stent thrombosis.

Conclusions

Preliminary experience in patients demonstrates a good performance of the SE. This newly designed implant maintains the engineering characteristics of Surpass flow diverters, including precise placement due to its lower foreshortening and a high mesh density, yet can be deployed through a significantly lower-profile delivery system.

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.

Endovascular treatment of vertebral artery dissecting aneurysm: A single-center experience

The aim of the present study was to explore the optimal treatment strategy for patients with vertebral artery dissecting aneurysms via the endovascular approach. A total of 47 patients (50 aneurysms, including 28 ruptured and 22 unruptured) underwent endovascular treatment between January 2012 and March 2018. Of these aneurysms, 18 were treated by parent artery occlusion, 11 by stent implantation and 21 by stent-assisted coiling. The complete occlusion rate was 100% (18/18) in aneurysms treated by parent artery occlusion and 46.9% (15/32) for stent implantation with or without coiling. External drainage was performed in 8 patients with ruptured aneurysms. Post-operative bleeding occurred in 2 patients treated by stent-assisted coiling. Ventriculo-peritoneal shunt was performed in 4 patients due to delayed hydrocephalus. Post-operative frontal hematoma occurred in one patient treated by stent-assisted coiling. The mortality was 6.4% (3/47) prior to discharge. The recurrence rate was 8.3% (1/12) in aneurysms treated by parent artery occlusion and 13.6% (3/22) in those treated by stent implantation with or without coiling. A total of 39 patients were followed up for 14.56±14.91 months. The good outcome rates were 100% (28/28) in patients with unruptured aneurysms and a Hunt-Hess grade of 1–3, and 72.7% (8/11) in patients with a Hunt-Hess grade of 4 or 5. In conclusion, the present study indicated that endovascular treatment is a safe and efficient method for patients with vertebral artery aneurysm. The treatment strategy should be based on the patient's condition and aneurysmal characteristics. Parent artery occlusion may be suitable for selected patients with ruptured vertebral artery aneurysms.

Pipeline Embolization Device for Treatment of Craniocervical Internal Carotid Artery Dissections: Report of 3 Cases

BACKGROUND

Dissecting pseudoaneurysms of the craniocervical circulation are uncommon, accounting for only 3% of all cerebral aneurysms. These aneurysms pose a challenge due to their location and anatomic configuration. The Pipeline Embolization Device (PED) is a flow diversion technique that successfully treats aneurysms by diverting blood flow away from the aneurysm and reconstructing the diseased parent artery by altering its hemodynamics.

CASE DESCRIPTION

We report 3 cases in which the PED was used to treat craniocervical carotid artery dissection with associated pseudoaneurysms. A single PED was used in the first case, 4 PEDs were used in the second case, and 3 PEDs and a PRECISE PRO RX carotid stent were placed in the third case. All 3 patients achieved full neurologic recovery postoperatively. Cerebral angiography performed postoperatively demonstrated revascularization, good laminar flow, and no in-stent or adjacent stenosis.

CONCLUSIONS

PED placement offers a safe and effective method of treating spontaneous or traumatic craniocervical carotid artery dissections with excellent neurologic outcomes postoperatively and complete long-term aneurysmal occlusion.

Reconsiderations on the use of pipeline embolization device in the treatment of intracerebral aneurysms with special angioarchitecture: fetal PCA, AVM, V-B junction and DAVF

Background

Pipeline embolization device (PED) has proved its safety and efficacy in the treatment of intracranial large and giant side-wall aneurysms. With the accumulation of treatment experience, it is an inevitable trend to expand its off-label use on aneurysms. Whether flow diversion is safe and efficient in cases with special angioarchitecture has rarely been explored.

Methods

We performed a retrospective analysis of 210 consecutive patients treated by PED for intracerebral aneurysms in our center. Except for aneurysm, those patients also presented with special angioarchitecture: Fetal PCA, AVM, V-B junction and DAVF.

Results

Nine patients were qualified for the study. 1 was with fetal PCA, the aneurysm remained patent on 4-month follow-up. 2 with ipsilateral AVMs, one patient died due to brain hemorrhage 20 days after the operation, the other one was only partially embolised on 6 month follow up. 3 aneurysms located at V-B junction, angiographic follow up on 3 months demonstrated no complete occlusion of both the aneurysms, the other patients were still on follow up. All of the 3 cases with concomitant DAVF are completely occluded during short to midterm follow up.

Conclusions

PED for aneurysms incorporated the fetal PCA and V-B junction might meet a high propensity for incomplete occlusion during short term follow up. Aneurysm with ipsilateral AVM is not suitable for PED treatment due to the risk of hemorrhage and incomplete occlusion during midterm follow up. For aneurysm with concurrent DAVF, PED treatment is safe and efficient relatively in one session or by staged operation.

Dissecting aneurysm of vertebral artery involving the origin of posteroinferior cerebellar artery treated with retrograde stent placement and coil embolization in the era of flow diverter

Ruptured vertebral artery (VA) dissecting aneurysm carries high risk of rerupture and mortality if not treated immediately. Dissecting aneurysm of the VA involving the posteroinferior cerebellar artery (PICA) origin is difficult to treat by surgical and endovascular route. With the availability of flow diversion device for reconstructive procedure, endovascular treatment has now become easy to treat difficult aneurysm while maintaining the patency of the PICA. However, instead of using flow diverter (FD) in our case, we successfully treated dissecting VA aneurysm involving the PICA origin with retrograde stent placement from distal right VA to the left PICA to maintain the patency of PICA and occlusion of dissecting aneurysm of VA with detachable coils instead of performing surgical bypass and FD placement.

Flow Alteration Therapy for Ruptured Vertebral Artery Dissecting Aneurysms Involving the Posterior Inferior Cerebellar Artery

Surgery for- and endovascular treatment of vertebral artery (VA) dissecting aneurysms involving the origin of the posterior inferior cerebellar artery (PICA) remain challenging. Their ideal treatment is complete isolation of the aneurysm by surgical or endovascular trapping plus PICA reconstruction. However, postoperative lower cranial nerve palsy and medullary infarction are potential complications. We report four patients with VA dissecting aneurysms involving the PICA origin who were treated by occipital artery (OA)-PICA bypass followed by proximal occlusion of the VA and clip ligation of the PICA origin instead of trapping. There were no procedural or ischemic complications. In all patients, angiography performed 2–3 weeks later showed good patency of the bypass graft and complete obliteration of the aneurysm. During the follow-up period ranging from 1 to 14 years, none experienced bleeding. Although retrograde blood flow to the dissecting aneurysm persisted in the absence of trapping, iatrogenic lower cranial nerve injury could be avoided. The decrease in aneurysmal flow might elicit spontaneous thrombosis and prevent aneurysmal rerupture. Our technique might be less invasive than aneurysmal trapping and help to prevent rebleeding.

Treatment outcomes in cerebral artery dissection and literature review

Methods Patients with cerebral artery dissections were reviewed in a hospital setting from 2008 to 2015. Clinical presentations, lesion locations, treatment modalities, functional outcomes, and mortality were reviewed. Parent artery occlusion was the first choice for surgery or endovascular treatment of a hemorrhagic dissecting cerebral artery. Endovascular or surgical reconstructive treatment was indicated in patients whose parent artery could not be occluded. Favorable functional outcomes were determined using modified Rankin Scale (mRS) scores of 0-2. Results In total, 61 patients with cerebral artery dissections were admitted to the hospital. Seven (11.5%) had traumatic dissections. All traumatic dissections were located in the internal carotid arteries. Overall favorable outcome rate was about 57% (4/7). Spontaneous cerebral artery dissections were found in 54 patients. No difference in favorable outcomes was observed between parent vessel occlusion and selective occlusion with parent vessel preservation (or vessel reconstruction) (70% and 63%, respectively, p = 1.000). Patients who presented with spontaneous dissection without intracranial hemorrhage had more favorable outcomes than those with intracranial hemorrhage (79% and 52%, respectively, p = 0.045). The mortality rate of patients with spontaneous dissection was 7.4%. Conclusions Most of the traumatic dissections were located on the internal carotid arteries and spontaneous dissections were commonly located on vertebral arteries. Nonhemorrhagic spontaneous cerebral dissections had better functional outcomes after treatment. Endovascular and surgical management were effective treatments by parent vessel occlusion or reconstructions.

The Role of Hemodynamics in Intracranial Bifurcation Arteries after Aneurysm Treatment with Flow-Diverter Stents

BACKGROUND AND PURPOSE

Treatment of intracranial bifurcation aneurysms with flow-diverter stents can lead to caliber changes of the distal vessels in a subacute phase. This study aims to evaluate whether local anatomy and flow disruption induced by flow-diverter stents are associated with vessel caliber changes in intracranial bifurcations.

MATERIALS AND METHODS

Radiologic images and demographic data were acquired for 25 patients with bifurcation aneurysms treated with flow-diverter stents. Whisker plots and Mann-Whitney rank sum tests were used to evaluate if anatomic data and caliber changes could be linked. Symmetry/asymmetry were defined as diameter ratio 1 = symmetric and diameter ratio <1 = asymmetric. Computational fluid dynamics was performed on idealized and patient-specific anatomies to evaluate flow changes induced by flow-diverter stents in the jailed vessel.

RESULTS

Statistical analysis identified a marked correspondence between asymmetric bifurcation and caliber change. Symmetry ratios were lower for cases showing narrowing or subacute occlusion (medium daughter vessel diameter ratio = 0.59) compared with cases with posttreatment caliber conservation (medium daughter vessel diameter ratio = 0.95). Computational fluid dynamics analysis in idealized and patient-specific anatomies showed that wall shear stress in the jailed vessel was more affected when flow-diverter stents were deployed in asymmetric bifurcations (diameter ratio <0.65) and less affected when deployed in symmetric anatomies (diameter ratio ∼1.00).

CONCLUSIONS

Anatomic data analysis showed statistically significant correspondence between caliber changes and bifurcation asymmetry characterized by diameter ratio <0.7 (P < .001). Similarly, computational fluid dynamics results showed the highest impact on hemodynamics when flow-diverter stents are deployed in asymmetric bifurcations (diameter ratio <0.65) with noticeable changes on wall sheer stress fields. Further research and clinical validation are necessary to identify all elements involved in vessel caliber changes after flow-diverter stent procedures.

The Use of Flow Diverter in Ruptured, Dissecting Intracranial Aneurysms of the Posterior Circulation

OBJECTIVE

Acute dissecting aneurysms of the posterior circulation are a rare cause of subarachnoid hemorrhage. Established endovascular treatment options include parent artery occlusion and stent-assisted coiling, but appear to be associated with an increased risk of ischemic stroke. Vessel reconstruction with flow diverters is an alternative treatment option; however, its safety and efficacy in the acute stage remains unclear.

METHODS

This is a multicentric retrospective analysis of 15 consecutive acutely ruptured dissecting posterior circulation aneurysms treated with flow diverters. The primary end point was favorable aneurysm occlusion, defined as OKM C1-3 and D (O'Kelly Marotta scale). Secondary end points were procedure-related complications and clinical outcome.

RESULTS

Nine of 15 aneurysms (60%) arose from the intradural portion of the vertebral artery, 3 were located on the posterior inferior cerebellar artery and 1 each on the anterior inferior cerebellar artery, posterior cerebral artery, and basilar artery. Flow diverter placement was technically successful in 14 of 15 cases (93%). After endovascular treatment, none of the ruptured aneurysms rebled. Median clinical follow-up was 217 days and median angiographic follow-up was 203 days. Favorable occlusion was observed in 7 of 14 aneurysms (50%) directly after flow diverter placement; of those, 5 were completely occluded (36%). Seven patients (47%) with poor-grade subarachnoid hemorrhage died in the acute phase. Favorable clinical outcome (modified Rankin scale ≤2) was observed in 4 of 15 patients (27%) and a moderate outcome (modified Rankin scale 3/4) was observed in 5 of 15 patients (33%). All aneurysms showed complete occlusion at follow-up.

CONCLUSIONS

Flow diverters might be a feasible, alternative treatment option for acutely ruptured dissecting posterior circulation aneurysms and may effectively prevent rebleeding. Larger cohort studies are required to validate these results.

Predictive factors of medullary infarction after endovascular internal trapping using coils for vertebral artery dissecting aneurysms

OBJECTIVE The first choice of treatment in cases of vertebral artery dissecting aneurysms (VADAs) is endovascular internal trapping (EIT) of the dissecting segment using coils. However, this procedure carries the risk of medullary infarction, and the risk factors for this complication are not well understood. This study investigated the risk factors causing medullary infarction. METHODS One hundred patients who underwent EIT for VADAs were included in this study. Ninety-three patients presented with subarachnoid hemorrhage. In cases involving the posterior inferior cerebellar artery (PICA), partial internal trapping targeting the ruptured site was performed to preserve the PICA. The VADAs were classified into the distal VA stump group, proximal VA stump group, and entire VA stump group, according to the location of VA segments without adequate flow-out vessels (such as the PICA [VA stump]) at risk of delayed thrombosis. The occurrence of medullary infarction was examined in each group using diffusion-weighted MRI and/or clinical symptoms. Various measurements were performed on digital subtraction angiography, and the risk factors for medullary infarction were analyzed. RESULTS Medullary infarction occurred in 30 patients, affecting the posterolateral medulla in 27 patients and the anteromedial medulla in 3 patients. Medullary infarction occurred in 3 of 47 patients (6%) in the distal VA stump group, 10 of 19 patients (53%) in the proximal VA stump group, and 17 of 34 patients (50%) in the entire VA stump group. The length of trapping was significantly longer in the infarction group than in the noninfarction group but did not differ among the 3 groups. Total length (length of trapping plus VA stump) was a risk factor for medullary infarction in the proximal VA stumps. CONCLUSIONS The primary risk factor for medullary infarction after EIT is not the length of trapping; rather, it is the anatomical location of the VADAs. The risk of medullary infarction is low in cases with distal VA stumps, but the symptoms are severe. Preservation of the origin of the anterior spinal artery can reduce the risk of medullary infarction. The risk of medullary infarction is high in cases with proximal VA stumps, but the symptoms are mild. A shorter length of trapping, although less likely to lead to complications, cannot prevent medullary infarction because the total length depends on the anatomical location of the PICA and not on the surgical technique. Reconstructive therapy should be indicated for patients with ruptured VADAs at high risk of severe ischemic complications (e.g., patients with hypoplasia of the contralateral VA or cases involving the PICA or anterior spinal artery, which are inappropriate for partial internal trapping) or for patients with unruptured VADAs.

Flow diverter treatment of intracranial vertebral artery dissecting pseudoaneurysms

INTRODUCTION

Intracranial vertebral dissecting pseudoaneurysms are a rare, but increasingly recognized, cause of subarachnoid hemorrhage and ischemic stroke. The risks of aneurysm re-rupture and associated morbidity are high. The use of flow diverter stents for the treatment of these aneurysms has not been well studied.

OBJECTIVE

To report our data and provide a summarized review of literature using flow diverter stents for the treatment of intracranial vertebral artery dissecting pseudoaneurysms.

METHODS

We performed a retrospective analysis of flow diverter stents used for the treatment of intracranial vertebral artery dissecting pseudoaneurysms. Clinical, imaging, procedural, and follow-up data were collected.

RESULTS

We identified eight vertebral dissecting pseudoaneurysms in seven patients (5 (71.4%) female; median age 47 years (IQR 46-52)) who had undergone treatment with flow diverter stents. In 4/7 patients (57.1%) the aneurysm had ruptured; however, only one was treated in the acute phase. Median size of the largest diameter of the aneurysm was 6.3 mm (IQR 4.2-8.8), and 7/8 aneurysms (87.5%) were treated with a single flow diverter device. Three aneurysms were concurrently coiled. Angiographic complete occlusion was seen in 6/8 (75%) aneurysms at a median follow-up of 14 months (IQR 7.7-20.2). Two patients had periprocedural strokes with transient neurologic deficits. All patients had a good clinical outcome (modified Rankin Scale score ≤2). There were no re-treatments or aneurysm ruptures during the follow-up period.

CONCLUSIONS

Our experience suggests that flow diverter stent treatment of intracranial vertebral artery dissecting pseudoaneurysms is safe, and associated with good occlusion rates and favorable clinical outcomes.

Ruptured intracranial vertebral artery dissecting aneurysms: An evaluation of prognostic factors of treatment outcome

Objective Intracranial spontaneous vertebral artery dissecting aneurysms commonly occur in the third to fifth decades of life, and are mostly associated with hypertension. Patients present with intracranial haemorrhage or thromboembolic events. Patients who present with intracranial haemorrhage carry about a 70% risk of recurrent bleeding. Patients with a posterior-inferior cerebellar artery (PICA) or ipsilateral dominant vertebral artery involve selecting which parent vessel could not be sacrificed. Recent reconstructive techniques such as stent-assisted coiling embolisation and flow-diverting stents are effective treatments of choice. Methods Seventeen patients presented subarachnoid haemorrhage and nine patients with other symptoms. Sacrificing the parent vertebral artery was the first choice for surgical or endovascular methods. Endovascular reconstructive treatment by stent-assisted coiling embolisation was indicated in dissecting vertebral artery aneurysms with ipsilateral dominant vertebral artery or PICA involvement. Clinical outcomes were determined using the modified Rankin Score (mRS) at 90 days, with favourable outcomes defined as 0 to 2. Results Of the patients presenting with ruptured aneurysms, 11 (61.1%) had a good clinical outcome, with a mRS of 0-2. Favourable Hunt and Hess grading (65%), mild to moderate GCS (65%) and total occlusion of aneurysms after treatment (65%) were significantly good prognostic factors in patients with ruptured vertebral artery dissecting aneurysms. Conclusion Endovascular parent vessel sacrifice could be the first choice to treat a ruptured vertebral artery dissecting aneurysm. Stent-assisted coiling to preserve the patency of the parent artery and its branches is a promising treatment for vertebral artery dissections.

Ophthalmic artery occlusion after Pipeline Embolization Device placement with reconstitution of flow via an endoleak: a report of two cases

The Pipeline Embolization Device (PED) is a flow diverting stent used in the treatment of a wide variety of intracranial aneurysms. The device differs from traditional stents used in stent-assisted coil embolization in that it has a tighter lattice structure with smaller cell sizes designed specifically to disrupt blood flow into aneurysms rather than only to retain coils within aneurysms. While the PED has been shown to be safe and effective, it has a unique risk profile that includes side branch and perforator vessel occlusion. Side branch occlusion in particular has been noted in several articles to occur at a relatively high rate with coverage of the ophthalmic artery origin by the PED. In this series, we present two cases of ophthalmic artery occlusion after PED placement with reconstitution of flow via an endoleak.

Pipeline embolization device as primary treatment for cervical internal carotid artery pseudoaneurysms

Background:

Limited data exists on the durability and occlusion rate of treating extracranial cervical internal carotid artery pseudoaneurysms using the pipeline embolization device (PED) flow-diverting stent.

Methods:

Three patients presenting with dissecting cervical internal carotid artery pseudoaneurysms were treated with the PED as the sole treatment modality.

Results:

In all three patients, successful aneurysmal occlusion and parent vessel reconstruction occurred on immediate angiography and continued on 6-month follow-up. No immediate or delayed complications were seen, and all patients remained neurologically intact.

Conclusion:

Complete aneurysmal occlusion and long-term angiographic occlusion can occur after PED treatment of cervical carotid pseudoaneurysms. In select patients, the PED can be a suitable primary treatment modality with good neurological outcome for cervical carotid pseudoaneurysms.

Treatment of posterior circulation non-saccular aneurysms with flow diverters: a single-center experience and review of 56 patients

BACKGROUND AND PURPOSE

Non-saccular aneurysms of the posterior fossa are an uncommon pathology with no clear treatment strategy. The use of flow-diverting stents (FDS) has had mixed results. We sought to evaluate our experience of FDS for the treatment of this pathology.

METHODS

We retrospectively reviewed our database of prospectively collected information for all patients treated only with flow diversion for an unruptured non-saccular aneurysm of the posterior circulation between February 2009 and April 2016. The aneurysms were classified as dolichoectasia, fusiform or transitional, and imaging characteristics including maximal diameter, disease vessel segment, MRI features (intra-aneurysmal thrombus, T1 hyperintensity in the aneurysmal wall, infarctions in the territory of the posterior circulation, and mass effect) were recorded alongside clinical and follow-up data.

RESULTS

We identified 56 patients (45 men) with 58 aneurysms. The average age of the patients was 63.5 years. Twenty-two patients were symptomatic from the aneurysms at presentation. The majority of the lesions were vertebrobasilar in location (44.8%) with isolated vertebral lesions representing 29.3% of aneurysms. Transitional aneurysms were the most common (48.2%). The mean maximal diameter of the aneurysms was 11 mm. Angiographic exclusion of the aneurysms was seen in 57.4% of aneurysms with follow-up (n=47). During the follow-up period nine patients died.

CONCLUSIONS

Treatment of non-saccular aneurysms of the posterior fossa is technically possible. Early treatment, particularly of the fusiform and transitional subtypes, is recognized, as is treatment prior to the development of symptoms. A 'watch and wait' strategy with regular imaging follow-up could be employed for asymptomatic dolichoectasia.

Bypass surgery for complex middle cerebral artery aneurysms: an algorithmic approach to revascularization

OBJECT Management of complex aneurysms of the middle cerebral artery (MCA) can be challenging. Lesions not amenable to endovascular techniques or direct clipping might require a bypass procedure with aneurysm obliteration. Various bypass techniques are available, but an algorithmic approach to classifying these lesions and determining the optimal bypass strategy has not been developed. The objective of this study was to propose a comprehensive and flexible algorithm based on MCA aneurysm location for selecting the best of multiple bypass options. METHODS Aneurysms of the MCA that required bypass as part of treatment were identified from a large prospectively maintained database of vascular neurosurgeries. According to its location relative to the bifurcation, each aneurysm was classified as a prebifurcation, bifurcation, or postbifurcation aneurysm. RESULTS Between 1998 and 2015, 30 patients were treated for 30 complex MCA aneurysms in 8 (27%) prebifurcation, 5 (17%) bifurcation, and 17 (56%) postbifurcation locations. Bypasses included 8 superficial temporal artery-MCA bypasses, 4 high-flow extracranial-to-intracranial (EC-IC) bypasses, 13 IC-IC bypasses (6 reanastomoses, 3 reimplantations, 3 interpositional grafts, and 1 in situ bypass), and 5 combination bypasses. The bypass strategy for prebifurcation aneurysms was determined by the involvement of lenticulostriate arteries, whereas the bypass strategy for bifurcation aneurysms was determined by rupture status. The location of the MCA aneurysm in the candelabra (Sylvian, insular, or opercular) determined the bypass strategy for postbifurcation aneurysms. No deaths that resulted from surgery were found, bypass patency was 90%, and the condition of 90% of the patients was improved or unchanged at the most recent follow-up. CONCLUSIONS The bypass strategy used for an MCA aneurysm depends on the aneurysm location, lenticulostriate anatomy, and rupture status. A uniform bypass strategy for all MCA aneurysms does not exist, but the algorithm proposed here might guide selection of the optimal EC-IC or IC-IC bypass technique.

Surgical Management of Intracranial Artery Dissection

Intracranial artery dissection (IAD) is a relatively rare cause of stroke, but it has been recognized increasingly with recent advances of the neuroimaging technique. Since rebleeding occurs frequently in the acute stage in the ruptured IAD, urgent surgical treatment should be performed to prevent rebleeding. On the other hand, surgical treatment for unruptured IAD is controversial because it has little risk for bleeding. However, surgical treatment for unruptured IAD may be considered if the formation or enlargement of the aneurysmal dilatation has been confirmed. Since there are several proposed surgical strategies for IAD, it is important to select an appropriate strategy on a case-by-case basis. If the risk of infarction due to vessel occlusion is high, combined bypass surgery should be considered.

State-of-art in surgical treatment of dissecting posterior circulation intracranial aneurysms

Vertebrobasilar (VB) intracranial dissecting aneurysms (IDAs) pose difficult therapeutic issues and are especially among the most difficult to manage surgically. There are, however, some cases where selective aneurysm obliteration by endovascular approach is impossible or is associated with an unacceptable risk of morbidity. This is particularly true when the aneurysm is dissecting, giant, or has a large neck. In such cases, surgical treatment may be the only alternative. Optimal management of these lesions is therefore challenging and treatment decisions have to be made on a case-by-case basis. Ideal treatment should be a complete surgical excision of the lesion; however, this procedure might only be possible after distal and proximal vessel wall occlusion which might not be tolerated by the patient depending on the location of the aneurysm. Therefore, formulation of recommendations concerning the surgical strategy remains still difficult due to inconsistency of surgical outcomes. The literature describing surgical strategy of VB IDAs is varying in quality and content, and many studies deal with only a few patients. In the presented review, the authors summarize the current knowledge on the incidence, pathogenesis, clinical presentation, and diagnostic procedures with special emphasis on surgical treatment of IDAs in posterior circulation.

Endovascular treatment for ruptured and unruptured vertebral artery dissecting aneurysms: a meta-analysis

Background

Different endovascular modalities have been applied to the treatment of vertebral artery dissecting aneurysms, the most commonly used being internal trapping and stent-assisted coiling, although the ideal treatment remains controversial.

Objective

To perform a meta-analysis to study clinical outcomes of patients with vertebral artery dissecting aneurysms who were treated with internal trapping or stent-assisted coiling.

Materials and methods

We conducted a meta-analysis of eight retrospective studies that compared internal trapping with stent-assisted coiling for the treatment of vertebral artery dissecting aneurysms. The primary outcomes of this study were immediate occlusion, long-term occlusion, good outcome ratio, perioperative mortality, and angiographic recurrence. Subgroup analyses were conducted of patients with ruptured versus unruptured vertebral artery dissecting aneurysms.

Results

Eight studies comprising a total of 188 patients were included in the analysis. For ruptured cases, in comparison with stent-assisted coiling groups, the patients treated with trapping techniques had a higher rate of immediate postoperative occlusion (OR=0.165; 95% CI 0.067 to 0.405; p<0.01), although there was no significant difference in long-term occlusion (OR=1.059; 95% CI 0.033 to 34.121; p=0.974), good clinical outcome rates, recurrence rates, and perioperative mortality. For unruptured cases, patients in the trapping groups also had higher immediate occlusion rates than those who underwent stent-assisted coiling (OR=0.175; 95% CI 0.043 to 0.709; p=0.015), while rates of both recurrence and good clinical outcome were similar between the two groups.

Conclusions

Both internal trapping and stent-assisted coiling are technically feasible for ruptured vertebral artery dissecting aneurysms, with high rates of good long-term neurologic outcomes and low recurrence and mortality rates. For unruptured aneurysms, conservative treatment is recommended. When a posterior inferior cerebellar artery (PICA) origin is involved, bypass surgery or vertebral artery-to-PICA stent placement plus coil embolization should be considered.

The Use of Flow Diversion for the Treatment of Intracranial Aneurysms: Expansion of Indications

Flow diversion is a novel concept for treating anatomically challenging intracranial aneurysms and has gained increasing acceptance. Flow diverter stents, such as the Pipeline Embolization Device (PED) (ev3-Covidien, Irvine, CA, USA), are approved for treating unruptured large and giant aneurysms from the internal carotid artery between the superior hypophyseal and cavernous segments. However, technological advances and recent clinical results suggest that flow diversion can be safely and effectively used in treating ruptured aneurysms, posterior circulation aneurysms, and distal anterior circulation aneurysms. In this brief review, we aim to investigate the recent evidence on the utilization of PEDs in these controversial vascular territories and to discuss whether the indications for flow diversion can be expanded.

Flow-diverting stents allow efficient treatment of unruptured, intradural dissecting aneurysms of the vertebral artery: An explanatory approach using in vivo flow analysis

OBJECT

Our study aimed to evaluate the efficiency of flow-diverting stents (FDS) in treating unruptured, intradural dissecting aneurysms of the vertebral artery (VADAs). Additionally, the effect of FDS on the aneurysmal flow pattern was investigated by performing in vivo flow analysis using parametric color coding (PCC).

METHODS

We evaluated 11 patients with unruptured, intradural VADAs, treated with FDS. Pre- and postinterventional DSA-series were postprocessed by PCC, and time-density curves were calculated. The parameters aneurysmal inflow-velocity, outflow-velocity and relative time-to-peak (rTTP) were calculated. Pre- and postinterventional values were compared and correlated with the occlusion rate after six months.

RESULTS

Follow-up DSA detected 10 aneurysms occluded, meaning an occlusion rate of 91%. No procedure-related morbidity and mortality was found. Flow analyses revealed a significant reduction of aneurysmal inflow- velocity and prolongation of rTTP after FDS deployment. Concerning aneurysm occlusion, the postinterventional outflow-velocity turned out to be a marginally statistically significant predictor. A definite threshold value (-0.7 density change/s) could be determined for the outflow-velocity that allows prediction of complete aneurysm occlusion with high sensitivity and specificity (100%).

CONCLUSIONS

Using FDS can be considered an efficient and safe therapy option in treating unruptured, intradural VADA. From in vivo flow analyses the postinterventional aneurysmal outflow-velocity turned out to be a potential predictor for later complete aneurysm occlusion. Here, it might be possible to determine a threshold value that allows prediction of aneurysm occlusion with high specificity and sensitivity. As fast, applicable and easy-to-handle tool, PCC could be used for procedural monitoring and might contribute to further treatment optimization.

Effect of coil packing proximal to the dilated segment on postoperative medullary infarction and prognosis following internal trapping for ruptured vertebral artery dissection

INTRODUCTION

Medullary infarction is an important complication of internal trapping for vertebral artery dissection. This study investigated risk factors for medullary infarction following internal trapping of ruptured vertebral artery dissection.

METHODS

We retrospectively studied 26 patients with ruptured vertebral artery dissection who underwent endovascular treatment and postoperative magnetic resonance imaging between April 2001 and March 2013. Clinical and radiological findings were analyzed to identify factors associated with postoperative medullary infarction.

RESULTS

Ten of the 26 patients (38%) showed postoperative lateral medullary infarction on magnetic resonance imaging. Multivariate logistic regression analysis revealed that medullary infarction was independently associated with poor clinical outcome (odds ratio (OR) 17.01; 95% confidence interval (CI) 1.68-436.81; p=0.032). Univariate analysis identified vertebral artery dissection on the right side and longer length of the entire trapped area as risk factors for postoperative medullary infarction. When the trapped area was divided into three segments (dilated, distal, and proximal segments), proximal segment length, but not dilated segment length, was significantly associated with medullary infarction (OR 1.55 for a 1-mm increase in proximal segment length; 95% CI 1.15-2.63; p=0.027). Receiver operating characteristic analysis showed that proximal segment length offered a good predictor of the risk of postoperative medullary infarction, with a cut-off value of 5.8 mm (sensitivity 100%; specificity 82.3%).

CONCLUSIONS

Longer length of the trapped area, specifically the segment proximal to the dilated portion, is associated with a higher incidence of medullary infarction following internal trapping, indicating that this complication may be avoidable.

Endovascular parent vessel sacrifice in ruptured dissecting vertebral and posterior inferior cerebellar artery aneurysms: clinical outcomes and review of the literature

Background

Ruptured intracranial dissecting aneurysms must be secured quickly to prevent re-hemorrhage. Endovascular sacrifice of the diseased segment is a well-established treatment method, however postoperative outcomes of symptomatic stroke and re-hemorrhage rates are not well reported, particularly for the perforator-rich distal vertebral artery or proximal posterior inferior cerebellar artery (PICA).

Methods

We retrospectively reviewed cases of ruptured distal vertebral artery or PICA dissecting aneurysms that underwent endovascular treatment. Diagnosis was based on the presence of subarachnoid hemorrhage on initial CT imaging and of a dissecting aneurysm on catheter angiography. Patients with vertebral artery aneurysms were selected for coil embolization of the diseased arterial segment based on the adequacy of flow to the basilar artery from the contralateral vertebral artery. Patients with PICA aneurysms were generally treated only if they were poor surgical candidates. Outcomes included symptomatic and asymptomatic procedure-related cerebral infarction, recurrent aneurysm rupture, angiographic aneurysm recurrence, and estimated modified Rankin Scale (mRS).

Results

During the study period, 12 patients with dissecting aneurysms involving the distal vertebral artery (n=10) or PICA (n=2) were treated with endovascular sacrifice. Two patients suffered an ischemic infarction, one of whom was symptomatic (8.3%). One patient (8.3%) died prior to hospital discharge. No aneurysm recurrence was identified on follow-up imaging. Ten patients (83%) made a good recovery (mRS ≤2). Median clinical and imaging follow-up periods were 41.7 months (range 0–126.4 months) and 14.3 months (range 0.03–88.6 months), respectively.

Conclusions

In patients with good collateral circulation, endovascular sacrifice may be the preferred treatment for acutely ruptured dissecting aneurysms involving the distal vertebral artery.

Epidemiology, pathophysiology, diagnosis, and management of intracranial artery dissection

Spontaneous intracranial artery dissection is an uncommon and probably underdiagnosed cause of stroke that is defined by the occurrence of a haematoma in the wall of an intracranial artery. Patients can present with headache, ischaemic stroke, subarachnoid haemorrhage, or symptoms associated with mass effect, mostly on the brainstem. Although intracranial artery dissection is less common than cervical artery dissection in adults of European ethnic origin, intracranial artery dissection is reportedly more common in children and in Asian populations. Risk factors and mechanisms are poorly understood, and diagnosis is challenging because characteristic imaging features can be difficult to detect in view of the small size of intracranial arteries. Therefore, multimodal follow-up imaging is often needed to confirm the diagnosis. Treatment of intracranial artery dissections is empirical in the absence of data from randomised controlled trials. Most patients with subarachnoid haemorrhage undergo surgical or endovascular treatment to prevent rebleeding, whereas patients with intracranial artery dissection and cerebral ischaemia are treated with antithrombotics. Prognosis seems worse in patients with subarachnoid haemorrhage than in those without.

Treatment of vertebrobasilar fusiform aneurysms with Pipeline embolization device

OBJECT

Treatment of complex intracranial aneurysms with Pipeline embolization device (PED) (ev3/Covidien Vascular Therapies) has gained recent popularity. One application of PEDs that is not well described in the literature is the utility and long-term safety in treatment of vertebrobasilar fusiform (VBF) aneurysms. Despite the advancements in endovascular therapy, VBF aneurysms continue to challenging pathology. The authors provide long-term follow-up of VBF aneurysms treated with PEDs.

METHODS

We retrospectively reviewed four patients that were treated at Louisiana State University Health Sciences Center in Shreveport with PEDs for VBFs from 2012 to 2014. Each patient was discussed in a multidisciplinary setting between neurosurgeons and neurointerventionalists. Each patient underwent platelet function tests to ensure responsiveness to anti-platelet agents and was treated by one neurointerventionalist (HC). All patients were placed on aspirin and Plavix and were confirmed for therapeutic response prior to discharge.

RESULTS

Follow-up ranged from 12 to 25 months, with a mean of 14.25 months. Two cases presented with a recurrence after the initial treatment, both of which required subsequent treatment. Of the four patients treated, one patient developed hemiparesis and three died.

CONCLUSION

Despite reports describing successful treatment of VBF aneurysms with PEDs, delayed complications after obliteration and remodeling can occur. We describe our institutional experience of VBFs treated with PEDs. Treatment of holobasilar fusiform aneurysms may carry a worse prognosis after treatment. Further long-term follow-up will provide a better understanding of this pathology.

Treatment of unruptured vertebral dissecting aneurysms: internal trapping or stent-assisted coiling

PURPOSE

Endovascular treatment is an attractive approach for the treatment of unruptured vertebral dissecting aneurysms, and includes internal trapping and stent-assisted coil embolization. However, the optimal therapy remains debatable. We reviewed our experience with both endovascular treatment modalities and compared the safety, efficacy, and short-term outcomes for each approach.

MATERIALS AND METHODS

We retrospectively reviewed 65 consecutive patients with unruptured vertebral dissecting aneurysms who underwent endovascular treatment between January 2003 and January 2014. 24 patients underwent endovascular internal trapping (group A) while 41 patients underwent stent-assisted coiling (group B). Thirteen patients underwent single stent with coiling while 28 patients underwent double or three stent-assisted coiling. Short-term outcomes were evaluated using the modified Rankin Scale.

RESULTS

A favorable clinical outcome was achieved in 58 of 65 patients. Procedure-related complications included ischemic symptoms (n = 6) and recurrence (n = 4). There was no statistical difference in modified Rankin Scale scoring between groups. Group A patients had more ischemia symptoms compared with group B patients (p = 0.043), Group B patients had higher recurrence rates compared with group A patients, but the difference had no statistical significance (p = 1.00). However, recurrence only occurred in patients who underwent stent-assisted coiling alone (p = 0.046).

CONCLUSION

Stent-assisted coiling for unruptured vertebral dissecting aneurysms may maintain artery patency. Multilayer disposition of stents with coils may decrease complications and facilitate aneurysm occlusion. Larger, prospective studies are necessary to determine the long-term outcomes of reconstructive therapy.