Spontaneous delayed migration/shortening of the pipeline embolization device: report of 5 cases

Recanalization of a chronic occlusion flow-diverter device in a patient with a paraclinoid giant aneurysm recurrence. Clinical observation

Paraclinoid internal carotid artery (ICA) aneurysms are associated with a high mortality rate, which gradually increases without intervention. Surgical clipping or coiling of large aneurysms with inadequate neck and adductor artery expansion will not guarantee a successful outcome. Carotid surgical trapping or endovascular occlusion of the adductor artery can help to isolate the aneurysm from circulation, but it comes at the expense of sacrificing a major blood vessel responsible for significant cerebral perfusion. Currently, a technique has been developed to redirect blood flow and stimulate gradual thrombosis in the aneurysm cavity to reduce pressure on its walls. However, in cases of recurrent aneurysm and stent thrombosis in these patients, it is necessary to consider destructive surgery. The 65-year-old patient, who had a history of migraine, was diagnosed with a large aneurysm. He was initially treated with the Pipeline Flex stent from Medtronic, but after 5 months, he experienced 2 transient ischemic attacks. Subsequent CT scans revealed no signs of brain damage, but a brain CTA revealed the recurrence of an internal carotid artery paraclinoid aneurysm with the occlusion of the pipeline device and contrast flowing parallel to the aneurysm wall. This case is an example of successful recanalization of an occluded flow diverter device in a patient with recurrent internal carotid aneurysm.

Spontaneous delayed migration or shortening after pipeline embolization device treatment of intracranial aneurysm: incidence, management, and risk factors

BACKGROUND

Studies reporting spontaneous delayed migration or shortening (SDMS) after treatment with the Pipeline Embolization Device (PED) are limited. This study aimed to evaluate the incidence of SDMS after PED treatment, propose management strategies, and identify the risk factors contributing to its occurrence.

METHODS

We retrospectively reviewed consecutive patients with an intracranial aneurysm (IA) treated with PEDs at three institutions. SDMS was classified as type I or II based on whether the PED covered the aneurysm neck.

RESULTS

The total cohort comprised 790 patients. SDMS was identified in 24 (3.04%) patients. Eighteen of the 24 patients had type I SDMS and did not require retreatment, while the remaining six patients had type II SDMS and all received retreatment. Multivariate logistic regression showed that the difference between the proximal and distal parent artery diameters (DPAD) (adjusted OR 2.977; 95% CI 1.054 to 8.405; P=0.039) and device tortuosity index (DTI) (adjusted OR 8.059; 95% CI 2.867 to 23.428; P<0.001) were independent predictors of SDMS after PED treatment, while the difference in length (DL) (adjusted OR 0.841; 95% CI 0.738 to 0.958; P=0.009) and PED plus coiling (adjusted OR 0.288; 95% CI 0.106 to 0.785; P=0.015) were protective factors.

CONCLUSION

The incidence of SDMS after PED treatment of IA was 3.04%. For patients with type I SDMS with incomplete aneurysm occlusion we recommend continuous imaging follow-up while, for patients with type II SDMS, we recommend aggressive retreatment. The DPAD and DTI were independent risk predictors of SDMS after PED treatment, while the DL and PED plus coiling were protective factors.

Delayed rupture of a large intracranial internal carotid artery aneurysm after flow diverter placement

Background

Delayed rupture after flow diverter (FD) placement is a serious complication, and often it leads to death; however, the exact mechanism leading to the rupture remains unclear. Therefore, in this case, study, we report a case of delayed rupture after FD placement and discuss its causes.

Case Description

This study presents the case of a 69-year-old female with multiple aneurysms who underwent FD placement with coil embolization for a large intracranial internal carotid artery aneurysm. Postoperatively, the patient had no significant symptoms, and angiography and magnetic resonance imaging revealed decreased intra-aneurysmal blood flow. However, on the 3rd postoperative day, she developed a sudden disturbance of consciousness. Computed tomography revealed a massive subarachnoid hemorrhage, diagnosed as a delayed rupture. We decided to withhold therapy due to her serious condition. Previous studies have suggested that hemodynamic mechanisms can cause delayed aneurysm rupture. Based on the computational fluid dynamics (CFD) of the aneurysm, we suggest that an increase in intra-aneurysmal pressure after FD placement may have caused the delayed rupture.

Conclusion

Preoperative CFD analysis may help evaluate the risk of delayed rupture for large aneurysms with a high inflow from the parent vessel.

Comaneci stent-angioplasty for the optimization of inadequately deployed flow diverter stents

BACKGROUND AND PURPOSE

In endovascular procedures, inadequate deployment of a flow diverter stent is a highly concerning technical complication that can lead to acute parent vessel occlusion and ischaemic events. This study aimed to assess the off-label use of the Comaneci device in managing technical difficulties associated with flow diversion.

MATERIALS AND METHODS

We conducted an analysis of all flow diverter procedures documented in our prospectively collected database. Our objective was to identify patients with inadequately deployed implants who underwent Comaneci stent-angioplasty. Both Comaneci 17 and Comaneci 21 devices were utilized to address and remediate technical complications related to stent deployment. We reviewed anatomical features, technical details, intraprocedural complications, as well as clinical and angiographic outcomes.

RESULTS

Thirty-one Comaneci devices were employed to remediate 31 inadequately deployed flow diverter stents. Successful resolution of technical complications associated with flow diverter placement was achieved in all attempted cases. No clinically significant complications were attributed to the technique, and no mortality was observed during the study.

CONCLUSION

Technical issues arising from flow diverter stent deployment are formidable complications. Familiarity with appropriate corrective manoeuvres is essential to achieve successful outcomes. The Comaneci device can be safely and effectively incorporated into the range of techniques used to rectify inadequately deployed stents.

Acute Distal Migration and Shortening of the Flow-Redirection Endoluminal Device: A Case Report

Objective

The flow diverter (FD) is a promising device. Apart from two main complications, hemorrhagic and ischemic ones, stent migration is reportedly an unusual complication. In particular, distal migration of the FD has rarely been reported. We report a case of asymptomatic acute distal migration of the flow-redirection endoluminal device (FRED).

Case Presentation

A 50-year-old woman was incidentally diagnosed with an unruptured right internal carotid-ophthalmic artery aneurysm with a maximum diameter of 8.0 mm, and she subsequently underwent endovascular treatment with FRED. Based on the vessel diameter (3.8 mm proximal and 3.6 mm distal to the aneurysm), a 4.0-mm-diameter and 18-mm-long FRED was deployed without postoperative complications. However, on MRA 12 months after treatment, the aneurysm was not occluded; angiography showed distal migration of the FRED. The postoperative MRA and skull X-ray images were retrospectively reviewed to determine the period of the migration. The skull X-ray images and the signal loss area due to the FRED on MRA 1 day after the treatment had already demonstrated the migration of the FRED. In the second treatment, a 4.0-mm-diameter and 23-mm-long FRED was deployed in an overlapping fashion up to the proximal part of the carotid siphon. Prompt identification of distal migration of the FD without neurologic signs could be challenging.

Conclusion

It is important to follow up meticulously with MRA and skull X-ray images after FD treatment for detecting stent migrations as early as possible.

Silk + flow-diverter stent for the treatment of intracranial aneurysms associated with balloon angioplasty: A retrospective study

Background

The silk + flow-diverter stent is increasingly used to treat complex intracranial aneurysms including wide-neck and fusiform aneurysms. Balloon angioplasty has been used to better appose the flow diverter (FD) to the vessel wall and, thus, improve aneurysm occlusion rates and decrease periprocedural complications. Sparse data are available concerning the results of this technique. We report our experience with silk + FD associated with balloon angioplasty for the treatment of intracranial aneurysms.

Methods

A retrospective study was conducted on all patients treated by the silk + FD. Clinical charts, procedural data, and angiographic results were reviewed and compared between those treated with balloon angioplasty. A multivariate analysis was conducted to identify predictors of complications, occlusion, and outcome.

Results

Between July 2014 and May 2016, we identified 209 patients with 223 intracranial aneurysms. There were 176 (84.2%) women and 33 (15.8%) men. The most common stent size used was 4.5 mm in 101 patients (46.1%), followed by 4 mm in 57 patients (26%). Univariate analysis observed that stent diameter was significantly related to aneurysm occlusion (P < 0.05). Patients with more than 1 aneurysm treated with silk + stent have a 9.07 times greater chance of having complications in the procedure than patients with only 01 aneurysm (OR = 9.07; P = 0.0008). Patients who had angioplasty without the use of a balloon have a 13.69-times-higher risk of complications (OR = 13.69; P = 0.0003). Older age, larger aneurysms, and the use of more than 1 FD device were predictors of recanalization.

Conclusion

Endovascular treatment of intracranial aneurysms with the silk + FD associated with balloon angioplasty is a safe and effective therapeutic option. Balloon angioplasty in combination with FD lowers the risk of complications. Higher complication rates and worse outcomes are associated with older age and large aneurysms.

The Rationale Behind Transcirculation Neuroendovascular Interventions: Literature Review Through a Case-Series Approach

BACKGROUND

With the development of advanced endovascular techniques and materials, neurointerventionalists can perform challenging and complex cases that were previously difficult to perform. Transcirculation approaches could be a useful tool used in complicated cases, providing access to the target vessel, through the contralateral or opposite circulation, when anterograde access is difficult or nonachievable.

OBJECTIVE

To retrospectively review cerebrovascular interventions performed through a transcirculation approach performed by staff at our Institution.

METHODS

English-language studies, published until August 2022, reporting transcirculation interventions in the cerebrovascular circulation were retrospectively collected. Type of intervention, number of cases, rationale, and complications were analyzed. Furthermore, similar cases performed by staff currently at our institution were also reviewed and described.

RESULTS

Including our cases, a total of 273 transcirculation treatment approaches have been reported. Intracranial aneurysm embolization, stroke thrombectomies, intra-arterial ophthalmic chemotherapy, arteriovenous malformationss, arteriovenous fistulas embolizations, and intracranial angioplasty and stenting are common indications. Reason for using a retrograde approach were stent/balloon-assisted coiling of wide neck aneurysm in 116 cases, difficult angulation of branch in 91 cases, occlusion of parent vessel in 55 cases, and bailout/other in 11 cases.

CONCLUSION

Transcirculation approaches can be considered for cases where conventional anterograde treatment options are not feasible or as a bailout strategy in failed or complicated treatment attempts. They represent a strategy to consider when facing challenging cases, and if performed by experienced and dedicated neurointerventionalists, they can represent a safe alternative.

Effects of different stent size selection on pipeline embolization device treatment of intracranial aneurysms

Background

Pipeline embolization device (PED) is becoming increasingly common in therapeutic practice. In idealized model studies, treatment effectiveness may vary with different stent sizes in the same vasculature. The true effect of stent size selection in the clinical setting remains unknown, however.

Objective

To determine the true effect of stent size selection in the clinical setting.

Design

It is a retrospective review.

Methods

A retrospective review was conducted on consecutive patients with aneurysms treated with a PED at our institution. The primary exposures were the difference between the diameter of the stent and the parent artery (DD) and the difference between the length of the stent and the aneurysm neck (DL). The outcomes were the clinical and angiographic results, perioperative complications, balloon application, and in-stent stenosis. The results were generated using univariable and multivariable logistic regression and restricted cubic spline (RCS) curves.

Results

A larger DD was significantly associated with incomplete occlusion [odds ratio (OR) = 2.37; 95% confidence interval (CI) = 1.43-3.98; p < 0.001], while a larger DL was significantly associated with balloon application (OR = 1.12; 95% CI = 1.02-1.23; p = 0.021) and in-stent stenosis (>25%) (OR = 1.07; 95% CI = 1.01-1.16; p = 0.042). The RCS curve indicated that the risk of incomplete occlusion increased as the DD became larger, the possibility of balloon application increased as the DL increased when the DL was >5.7 mm, and the risk of in-stent stenosis (>25%) increased as the DL increased.

Conclusion

In the clinical setting, stent selection was associated with treatment effectiveness and may add to the treatment burden. These occurrences should be considered for aneurysms treated with PED.

Endovascular treatment of unruptured intracranial aneurysms with flow diverters: A retrospective long-term single center analysis

PURPOSE

The introduction of flow diverters (FDs) in 2007 greatly enhanced the treatment of intracranial aneurysms. Here, we present our long-term clinical experience in treating unruptured intracranial aneurysms with FDs.

METHODS

107 patients with unruptured aneurysms and treated with an FD between 2010 and 2019 were retrospectively reviewed. Aneurysm occlusion, procedural complications, and clinical outcome were evaluated.

RESULTS

Angiographic follow-up was available for 93 patients with a mean long-term follow-up time of 28.4 ± 21.6 months. Additional coiling was performed in 15.1% of patients (n = 14). Adequate aneurysm occlusion (Kamran grades 3 and 4) at long-term follow-up was achieved in 94.6% of patients (n = 88). 3.2% (n = 3) required endovascular retreatment since the last follow-up showed a lack of aneurysm occlusion (Kamran grade 0) due to a foreshortening of the FD. Incomplete opening of the FD and parent vessel occlusion was seen in 1.1% (n = 1) and 3.2% (n = 3) of patients, respectively. In-stent stenosis was observed in 57% (n = 53) of cases at short-term follow-up and 22.6% (n = 21) at long-term, which were moderate and asymptomatic overall. In-stent stenosis decreased significantly between short- and long-term follow-ups (31.4 ± 17.0% vs 9.7 ± 13.6%, respectively; p ≤ 0.001). Thromboembolic and hemorrhagic events occurred in 7.5% (n = 7) and 1.1% (n = 1) of patients, respectively. Good clinical outcome (modified Rankin scale: 0-2) was obtained in 97.8% (n = 91) leading to an overall treatment-related morbidity of 2.2% (n = 2). There was no procedural mortality.

CONCLUSION

Our study shows that FD treatment of unruptured intracranial aneurysms is effective and safe with high occlusion rates and low rates of permanent morbidity at long-term follow-up.

Mechanical property analysis and design parameter optimization of a novel nitinol nasal stent based on numerical simulation

Background: A novel braided nasal stent is an effective alternative to nasal packing after septoplasty that can be used to manage the mucosal flap after septoplasty and expand the nasal cavity. This study aimed to investigate the influence of design parameters on the mechanical properties of the nasal stent for optimal performance. Methods: A braided nasal stent modeling method was proposed and 27 stent models with a range of different geometric parameters were built. The compression behavior and bending behavior of these stent models were numerically analyzed using a finite element method (FEM). The orthogonal test was used as an optimization method, and the optimized design variables of the stent with improved performance were obtained based on range analysis and weight grade method. Results: The reaction force and bending stiffness of the braided stent increased with the wire diameter, braiding density, and external stent diameter, while wire diameter resulted as the most important determining parameter. The external stent diameter had the greatest influence on the elongation deformation. The influence of design parameters on von-Mises stress distribution of bent stent models was visualized. The stent model with geometrical parameters of 25 mm external diameter, 30° braiding angle, and 0.13 mm wire diameter (A3B3C3) had a greater reaction force but a considerably smaller bending stiffness, which was the optimal combination of parameters. Conclusion: Firstly, among the three design parameters of braided stent models, wire diameter resulted as the most important parameter determining the reaction force and bending stiffness. Secondly, the external stent diameter significantly influenced the elongation deformation during the compression simulation. Finally, 25 mm external diameter, 30° braiding angle, and 0.13 mm wire diameter (A3B3C3) was the optimal combination of stent parameters according to the orthogonal test results.

Clinical outcomes of pipeline embolization devices with shield technology for treating intracranial aneurysms

INTRODUCTION

As a common endovascular treatment for intracranial aneurysms, the pipeline embolization device (PED) is considered a standard treatment option, especially for large, giant, wide-necked, or dissecting aneurysms. A layer of phosphorylcholine biocompatible polymer added to the surface of the PED can substantially improve this technology. This PED with shield technology (pipeline shield) is relatively novel; its early technical success and safety have been reported. We conducted a systematic literature review with the aim of evaluating the efficacy and safety of the pipeline shield.

METHODS

We searched the PubMed, Embase, and Cochrane databases, following the preferred reporting items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines.

RESULTS

We selected five prospective and two retrospective studies for review. A total of 572 aneurysms were included; of these, 506 (88.5%) were unruptured. The antiplatelet regimens were heterogeneous. The rate of perioperative and postoperative complications was 11.1% [95% confidence interval (CI): 6.5-18.9%]. The adequate occlusion rate at 6 months was 73.9% (95% CI: 69.1-78.7%). The adequate occlusion rate of more than 12 months was 80.9% (95% CI: 75.1-86.1%). The mortality rate was 0.7% (95% CI: 0.2-1.5%). Subgroup analyses showed that aneurysm rupture status had no effect on aneurysm occlusion rate, patient morbidity, or mortality.

CONCLUSION

This review demonstrates the safety and efficacy of the pipeline shield for treating intracranial aneurysms. However, direct comparisons of the pipeline shield with other flow diverters are needed to better understand the relative safety and effectiveness of different devices.

Delayed aneurysm rupture in a patient treated with flow redirection endoluminal device: A case report and literature review

Background:

Delayed aneurysm rupture after flow-redirection endoluminal device (FRED) implantation is rare. We report a case of internal carotid-cavernous fistula (CCF) caused by a delayed aneurysm rupture of the cavernous portion of the internal carotid artery (ICA) after FRED implantation.

Case Description:

A 75-year-old woman had a gradually enlarging aneurysm at the C4 portion of the left ICA. We performed FRED implantation for the same. The FRED implantation procedure was smooth and the FRED expanded well and attached to the vessel wall. Five days after surgery, the patient developed a strong headache, hyperemia of the left eye, and disturbance of the left eye movement. Magnetic resonance imaging and angiography revealed a left CCF with cortical venous reflux. We performed transarterial aneurysmal and transvenous cavernous sinus embolization. Postoperatively, angiography showed no fistula and complete occlusion of the aneurysm; however, minor eye movement disorder persisted.

Conclusion:

To prevent the development of delayed aneurysm rupture in patients treated with FRED, preoperative consideration of whether to add coil embolization is important, even if the aneurysm is located in the C4 portion of the ICA and there is no risk of subarachnoid hemorrhage, including the size of aneurysm. In this report, we have tried to alert surgeons regarding the risk of delayed aneurysm rupture due to FRED implantation.

How precise is PreSize Neurovascular? Accuracy evaluation of flow diverter deployed-length prediction

OBJECTIVE

The use of flow-diverting stents has been increasingly important in intracranial aneurysm treatment. However, accurate sizing and landing zone prediction remain challenging. Inaccurate sizing can lead to suboptimal deployment, device waste, and complications. This study presents stent deployment length predictions offered in medical software (PreSize Neurovascular) that provides physicians with real-time planning support, allowing them to preoperatively "test" different devices in the patient's anatomy in a safe virtual environment. This study reports the software evaluation methodology and accuracy results when applied to real-world data from a wide range of cases and sources as a necessary step in demonstrating its reliability, prior to impact assessment in prospective clinical practice.

METHODS

Imaging data from 138 consecutive stent cases using the Pipeline embolization device were collected from 5 interventional radiology centers in the United Kingdom and retrospectively analyzed. Prediction accuracy was calculated as the degree of agreement between stent deployed length measured intraoperatively and simulated in the software.

RESULTS

The software predicted the deployed stent length with a mean accuracy of 95.61% (95% confidence interval [CI] 94.87%-96.35%), the highest reported accuracy in clinical stent simulations to date. By discounting 4 outlier cases, in which events such as interactions with coils and severe push/pull maneuvers impacted deployed length to an extent the software was not able to simulate or predict, the mean accuracy further increases to 96.13% (95% CI 95.58%-96.69%). A wide discrepancy was observed between labeled and measured deployed stent length, in some cases by more than double, with no demonstrable correlation between device dimensions and deployment elongation. These findings illustrate the complexity of stent behavior and need for simulation-assisted sizing for optimal surgical planning.

CONCLUSIONS

The software predicts the deployed stent length with excellent accuracy and could provide physicians with real-time accurate device selection support.

Surpass Evolve Flow Diverter for the Treatment of Intracranial Aneurysm: A Systematic Review

PURPOSE

This systematic review aims to summarize the evidence investigating the effectiveness and safety of the Surpass Evolve-Flow Diverter (SE-FD) to treat brain aneurysms.

METHOD

We searched MEDLINE, EMBASE, CINAHL, Web of Science, and Cochrane Library from January 2019 to 29 March 2022. Terms related to the "intracranial aneurysm" and "surpass evolve flow diverter" concepts were used to search the databases; Medical Subject Headings (MeSH) and reference hand search were also utilized.

RESULTS

The searches primarily identified 1586 documents. A total of five studies (four case series and one cohort) were included in this review. In the included studies, 192 (74 male and 118 females) patients with 198 aneurysms were involved. In total, 153 SE-FDs were used to treat 145 aneurysms. Complete occlusion was achieved in 69/145 (48%) cases and near-complete occlusion in 24/145 (17%) cases from aneurysms treated with SE-FD. Reported postoperative complications included stent thrombosis (n = 4 patients), hemorrhage (n = 5 patients), ischemia (n = 9 patients), and neurological complications (n = 12 patients). In total, four deaths were reported with only one related to the SE-FD procedure.

CONCLUSION

The results of this review are based on observational data, due to the absence of clinical trials. The findings of the included studies suggest that the effectiveness of the SE-FD procedure is lower than previous FDs but the safety is similar. The included studies also suggested that SE-FD has navigability and resistance to twisting, which makes the procedure an easier method to treat aneurysms that are proximal and distal to the circle of Willis deployment. This review highlights the urgency to conduct clinical trials to confirm these suggestions.

Effects of different stent wire mesh densities on hemodynamics in aneurysms of different sizes

Background

Intracranial stents are used to treat aneurysms by diverting the blood flow from entering into the aneurysmal dome. Although delayed rupture is rare, clinical outcomes are extremely poor in such cases. Hemodynamics after stent deployment may be related to delayed rupture and a better understanding of the basic characteristics of pressure changes resulting from stent deployment is needed; therefore, this study investigated the relationships between hemodynamics in aneurysms of different sizes treated using stents of different wire mesh densities.

Methods

Using computational fluid dynamics analysis, parameters related to velocity, volume flow rate, pressure, and residual volume inside the aneurysm were evaluated in digital models of 5 basic aneurysms of differing sizes (Small, Medium, Medium-Large, Large, and Giant) and using 6 different types of stent (varying number of wires, stent pitch and wire mesh density) for each aneurysm.

Results

Regardless of the aneurysm size, the velocity inside the aneurysm and the volume flow rate into the aneurysm were observed to continuously decrease up to 89.2% and 78.1%, respectively, with increasing stent mesh density. In terms of pressure, for giant aneurysms, the pressure on the aneurysmal surface elevated to 10.3%, then decreased to 5.1% with increasing stent mesh density. However, in smaller aneurysms, this pressure continuously decreased with increasing stent mesh density. The flow-diverting effect of the stents was limited when a stent with low mesh density (under 20%) was used with a giant aneurysm.

Conclusions

The present results indicate that the selection of appropriate stents according to aneurysm size may contribute to reduced risks of hemodynamic alternations related to stent deployment, which could reduce the incidence of delayed rupture.

A case of delayed foreshortening and disconnection of pipeline embolization device detected by chronological cone-beam computed tomography fusion image

OBJECTIVE

The morphological changes of the pipeline embolization device (PED; Medtronic, Minneapolis, MN, USA), such as delayed migration or foreshortening, can relate to the incomplete occlusion of aneurysms.

CASE PRESENTATION

A 30-year-old man with a giant cavernous carotid artery aneurysm was treated with two PEDs using the overlapping technique. Six months after treatment, follow-up angiography showed morphological changes of the PEDs and residual flow into the aneurysm. Chronological cone-beam computed tomography fusion imaging clearly revealed the dynamic foreshortening of the first PED and the disconnection of both PEDs, so we decided to implant an additional PED.

CONCLUSION

This case illustrates that a three-dimensional understanding can be useful for assessing the cause of treatment failure or recurrence.

Rupture of an adjacent cerebral aneurysm following the deployment of a Pipeline embolization device: illustrative case

BACKGROUND

Although the Pipeline embolization device (PED) is effective for intracranial aneurysm treatment, its impact on the surrounding vascular structure is unknown.

OBSERVATIONS

A 71-year-old woman was incidentally found to have a simultaneous large posterior communicating artery aneurysm and an ipsilateral small anterior choroidal artery aneurysm. She underwent flow diversion therapy for both aneurysms with a PED, but the distal shortening of the PED after deployment led to the exposure of the anterior choroidal artery aneurysm. Follow-up angiography revealed complete obliteration of the posterior communicating artery aneurysm, but the anterior choroidal artery aneurysm remained. Three years after the endovascular surgery, the patient experienced a subarachnoid hemorrhage due to the rupture of the anterior choroidal artery aneurysm. Retrospective analysis of angiographic images revealed a change in the vascular geometry surrounding the ruptured aneurysm after PED deployment; this was further accompanied by an increase in the flow velocity inside the aneurysm.

LESSONS

Because PED use might induce the adverse effects on the adjacent uncovered aneurysm by changing the vascular geometry and hemodynamic stress, a cautious therapeutic strategy, such as proper placement of the stent and using a longer and appropriate-sized PED, should be chosen when deploying the PED.

Distal migration of the flow-redirection endoluminal device immediately after treatment: A case report and literature review

Background:

A flow diverter (FD) has been a promising endovascular therapeutic modality for challenging intracranial aneurysms. However, stent migration has been an unusual complication. Until recently, among some types of FDs, the migration of the flow-redirection endoluminal device (FRED; MicroVention Inc., Aliso Viejo, CA, USA) has almost never been reported. Herein, we report a case of acute distal migration of a single FRED secondary to in-stent thrombi with symptomatic ischemic stroke and review the literature on the distal migration of FDs.

Case Description:

A 35-year-old woman was diagnosed with a left unruptured internal carotid-ophthalmic artery aneurysm. A 3.5 mm diameter and 17 mm long FRED was adequately deployed. The patient awoke from general anesthesia without neurological deficits. However, shortly after the procedure, the patient presented with conjugate deviation toward the left side, right severe hemiparesis, and total aphasia. Although the symptoms gradually improved, angiography was performed. Angiography revealed some in-stent thrombi and distal migration of the FRED, and initially, one of the left M2 inferior trunk branches was occluded by an embolic thrombus. However, the thrombus spontaneously migrated distally without any specific treatment. Finally, despite leaving the migrated stent in situ, the flow almost completely improved, and the patient’s neurologic deficits disappeared. Magnetic resonance imaging following treatment revealed only a small cerebral infarction in the left temporo-occipital area.

Conclusion:

Distal migration of an FD in an acute setting, including the FRED, may occur even following appropriate placement. In-stent thrombosis can cause distal stent migration and thromboembolic stroke.

Staged hybrid treatment for giant thrombosed fusiform aneurysm

Partially thrombosed intracranial aneurysm was difficult to treat because of higher recurrence rate compared to non-thrombosed saccular aneurysm. The author reports a case of partially thrombosed intracranial aneurysm causing transient ischemic symptom. A 40-year-old man presented with transient right hemiparesis. Brain magnetic resonance imaging (MRI) depicted low-signal intensity target-like mass lesion on left sylvian fissure, and magnetic resonance angiography (MRA) showed aneurysm on left middle cerebral artery bifurcation (MCBF), suggested thrombosed aneurysm. On operative finding, aneurysm wall had thick and atherosclerotic change, and it was fusiform aneurysm not saccular type. We initially planned direct clip for the aneurysm, but it was failed due to collapse of parent artery after clipping on aneurysm neck. To prevent ischemia, extracranial-intracranial bypass was performed and then thrombectomy with clip reconstruction. To remodeling the fusiform aneurysm, stent-assisted coiling was performed for remnant portion of aneurysm. With staged hybrid technique, giant thrombosed fusiform aneurysm was completely obliterated and the patient did not suffer any neurologic symptoms no longer.

Standardized post-catheter nursing intervention reduces incidence of catheter complications in the disabled elderly and improves their quality of life

OBJECTIVE

The aim of this study was to determine the effect of standardized post-catheter nursing intervention on awareness rate of clinical knowledge and behavior, treatment compliance, and incidence of catheter complications in the disabled elderly.

METHODS

A total of 84 elderly patients with indwelling catheters treated in our hospital from September 2019 to March 2020 were retrospectively analyzed. Based on different nursing methods, 39 cases treated by routine nursing intervention were included in the control group (CG), and 45 cases receiving standardized post catheter nursing intervention were assigned to the experimental group (EG). The two groups were compared in terms of the following items: awareness rate of knowledge and behavior, treatment compliance, incidence of catheter complications before and after nursing, hospitalization time, nursing satisfaction and quality of life (QOL).

RESULTS

The EG exhibited significantly shorter hospitalization time and lower incidence of catheter complications than CG. The awareness rate of knowledge and behavior, treatment compliance and nursing satisfaction were significantly higher in the EG than in the CG. Furthermore, the QOL scores were not significantly different between CG and EG before nursing intervention, but were significantly higher in the EG than the CG after nursing intervention.

CONCLUSIONS

Standardized post-catheter nursing intervention for the disabled elderly can better enhance the awareness rate of knowledge and behavior, improve treatment compliance and QOL of patients, and reduce the incidence of catheter complications.

Comparison of Pipeline Embolization and Coil Embolization for the Treatment of Large Unruptured Paraclinoid Aneurysms

The efficacy of flow diversion (FD) in the treatment of paraclinoid aneurysms has been established. The pipeline embolization device (PED) is one of the most commonly used FD devices. Coil embolization is also useful for treating paraclinoid aneurysms. This study aimed to compare the efficacy and safety of PED treatment and coil embolization for large unruptured paraclinoid aneurysms. This was a single-center, retrospective study of large unruptured paraclinoid aneurysms treated endovascularly between 2009 and 2019 (coil embolization between 2009 and 2015, and PED between 2015 and 2019). Cases with a follow-up period of less than 1 year and recurrence after coil embolization were excluded. The treatment outcomes between coil embolization and PED were compared. We investigated 45 patients with 45 large unruptured paraclinoid aneurysms treated by endovascular surgery in our institution. Twenty-four patients were treated with coil embolization and 21 with PED. In the PED group, the device cost was significantly lower (2,770.4 ± 699.5 vs. 1941.2 ± 552.8 [1000 yen], P = 0.03), procedure duration was significantly shorter (155.4 ± 66.7 vs. 95.1 ± 35.4 min, P <0.01), and the numbers of re-treatments were lower than those in the coil embolization group (41.7 vs. 14.3%, P = 0.05). Both PED and coil embolization were effective and safe for large unruptured paraclinoid aneurysms, and their treatment results were similar. The PED is more beneficial because of its lower cost, shorter procedure duration, and fewer retreatments, and is therefore more useful for the treatment of large unruptured paraclinoid aneurysms.

Development of a Virtual Stent Deployment Application to Estimate Patient-Specific Braided Stent Sizes

A virtual stent deployment application was developed to estimate the appropriate and patient-specific size of a braided stent for patients who undergo endovascular treatment for intracranial aneurysms. Comparing between the simulated deployed and the actual stents, we evaluated the accuracy of the simulation results. Our results indicated that lengths of the virtual and actual stents matched well despite the actual stent being affected by a geometrical change of the parent artery.Clinical Relevance-Surgeons need to be well-experienced to select an appropriate braided stent size for endovascular treatment of intracranial aneurysms, because the actual length of the deployed stent changes. This simulation will be helpful to make tailor-made surgical planning regardless of the surgeons' individual skill level.

First Experience of Three Neurovascular Centers With the p64MW-HPC, a Low-Profile Flow Diverter Designed for Proximal Cerebral Vessels With Antithrombotic Coating

Background: In the last decade, flow diversion (FD) has been established as hemodynamic treatment for cerebral aneurysms arising from proximal and distal cerebral arteries. However, two significant limitations remain—the need for 0.027” microcatheters required for delivery of most flow diverting stents (FDS), and long-term dual anti-platelet therapy (DAPT) in order to prevent FDS-associated thromboembolism, at the cost of increasing the risk for hemorrhage. This study reports the experience of three neurovascular centers with the p64MW-HPC, a FDS with anti-thrombotic coating that is implantable via a 0.021” microcatheter.

Materials and methods: Three neurovascular centers contributed to this retrospective analysis of patients that had been treated with the p64MW-HPC between March 2020 and March 2021. Clinical data, aneurysm characteristics, and follow-up results, including procedural and post-procedural complications, were recorded. The hemodynamic effect was assessed using the O'Kelly–Marotta Scale (OKM).

Results: Thirty-two patients (22 female, mean age 57.1 years) with 33 aneurysms (27 anterior circulation and six posterior circulation) were successfully treated with the p64MW-HPC. In 30/32 patients (93.75%), aneurysmal perfusion was significantly reduced immediately post implantation. Follow-up imaging was available for 23 aneurysms. Delayed aneurysm perfusion (OKM A3: 8.7%), reduction in aneurysm size (OKM B1-3: 26.1%), or sufficient separation from the parent vessel (OKM C1-3 and D1: 65.2%) was demonstrated at the last available follow-up after a mean of 5.9 months. In two cases, device thrombosis after early discontinuation of DAPT occurred. One delayed rupture caused a caroticocavernous fistula. The complications were treated sufficiently and all patients recovered without permanent significant morbidity.

Conclusion: Treatment with the p64MW-HPC is safe and feasible and achieves good early aneurysm occlusion rates in the proximal intracranial circulation, which are comparable to those of well-established FDS. Sudden interruption of DAPT in the early post-interventional phase can cause in-stent thrombosis despite the HPC surface modification. Deliverability via the 0.021” microcatheter facilitates treatment in challenging vascular anatomies.

Safety Evaluation and Flow Modification in the Anterior Cerebral Artery after Pipeline Embolization Device Deployment across the Internal Carotid Artery Terminus

Method

The clinical and imaging data of PEDs in the postmarket multicenter registry study (PLUS) in China were retrospectively analyzed, and patients were divided into two groups on the basis of the follow-up angiographic results: group 1 (no significant change in A1 blood flow) and group 2 (A1 occlusion or decreased blood flow). We collected patients' baseline data and evaluated the following imaging indicators: diameter and ratio of bilateral A1, M1, and internal carotid artery (ICA) vessels before stenting and the ratio of the PED size (sPED) to the ipsilateral ICA (I-ICA) diameter on the implantation side.

Results

A total of 1171 patients were included, of whom 48 met the inclusion criteria (17 in group 1 and 31 in group 2). In group 2, three patients experienced neurological deterioration at follow-up. From the univariate analysis of outcomes, single PED without coils, incomplete aneurysm occlusion (IAO), maximum aneurysm diameter, aneurysms involving the ICA bifurcation (ICAb), and large sPED/I-ICA diameter ratio were included in the multivariate analysis (P < 0.20). The multivariate regression analysis results showed that the ratio of sPED/I-ICA diameter was the factor influencing A1 vessel occlusion. The area under the ROC curve was 73.2%. When the sPED/I-ICA diameter ratio was 1.14, sensitivity was 70.6%, and specificity was 77.4%.

Conclusion

When an oversized PED is placed from M1 to the ICA, the higher porosity formed at the covered A1 orifice is conducive to maintaining stable A1 blood flow and reducing the risk of A1 vessel occlusion. This trial is registered with ClinicalTrials.gov identifier: NCT03831672.

Early clinical experience of using the Surpass Evolve flow diverter in the treatment of intracranial aneurysms

PURPOSE

Here, we presented our early experience with flow diversion procedures using the Surpass Evolve flow diverter (SE, Stryker) and reported the feasibility and safety profile compared to those of a control group treated with other types of flow diverters.

METHODS

We included 31 and 53 consecutive flow diversion procedures performed using the SE and other commercial flow diverters, respectively, to treat intracranial aneurysms at our institution. We used two commercial flow diversion systems in the comparison group: the pipeline embolization device and Surpass Streamline.

RESULTS

In the SE group, technical failures occurred in three (9.7%) cases, due to either incomplete wall apposition (n = 1, 3.2%) or stent migration (n = 2, 6.5%). Major complications occurred in four (12.9%) cases: delayed rupture of the target aneurysm (n = 1, 3.2%), major ischemic stroke (n = 1, 3.2%), sudden death from an unidentified cause (n = 1, 3.2%), and parent artery occlusion with stent thrombosis (n = 1, 3.2%). Balloon angioplasty was performed in eight (25.8%) cases. On post-procedure MRI, a DWI-positive lesion was detected in three (9.7%) cases. After multivariate adjustment, the SE group was independently associated with less procedural time of ≥ 90 min (adjusted OR, 0.09; 95% CI, 0.03-0.29; p < 0.001), balloon angioplasty (adjusted OR, 0.22; 95% CI, 0.07-0.75; p = 0.015), and DWI-positive lesions (adjusted OR, 0.04; 95% CI, 0.01-0.19; p < 0.001).

CONCLUSION

The SE is safe and easy to deploy.

Cerebral vasospasm resulted in "stent shortening" after pipeline assisted coil embolization for blood blister aneurysms

Blood blister aneurysms (BBAs) are intracranial arterial lesions appearing in nonbranching sites of the supraclinoid internal carotid artery as well as the basilar artery. Endovascular treatment of BBAs is still not well established because of the rarity of these lesions. We report incidences of BBAs with associated vasospasms. Treatment of the BBAs and associate vasospasms with single Pipeline Flex embolization device (PLED) assisted coiling resulted in seemly shorting of the PLEDs in 3 patients.A retrospective analysis of patients with BBAs who were treated with single PLED assisted coiling from July 2018 to October 2019 was conducted. Patients' ethnic and medical records, aneurysmal characteristics, intraoperative-rupture, cerebral vasospasm (CVS), postprocedure contrast filling, follow-up imaging, and results were analyzed. Neurological examination at baseline and outcome based on modified Rankin scale (mRS) at discharge as well as follow-ups were also documented.Six patients consisting of 5 females and 1 male, with a mean age of 48.3 years (range from 34-67) were identified during our analysis. All the BBAs were located in nonbranching site of supra-clinoidal segment of internal carotid artery with a mean neck width of 4.5 mm and mean aneurysm size of 4.23 mm. PLED assisted coiling's were performed in all of them. CVS was observed in 3 patients while 1 patient had an intraoperative-rupture of the BBA. Postprocedure contrast filling was still present in 1 patient. All the patients had good outcomes with discharge and follow-up mRS scores ≤ 2 except 1 patient with mRS score = 3 with aphasia.PLED assisted endovascular coiling is very safe and efficient in treating patients with BBAs. Resolution of CVSs after treatment made the PLEDs seemly shorter. Furthermore, a combination of arterial lengthening after gaining their tensile strength back and radical expansion of the PLED could account for the shortening.

Treatment of Intracranial Aneurysms Using the New Silk Vista Flow Diverter: Safety Outcomes at Short-Term Follow-Up

Background: Flow diverters are widely used as the first endovascular treatment option for complex brain aneurysms due to their high percentage of occlusion and low morbi-mortality. The Silk Vista device is a new generation of flow diverters designed to facilitate full visibility, improve apposition to the vessel wall, and enhance navigability. Indeed, its greatest advantage is that it enables the easier navigation of stents between 3.5 and 4.75 mm through a 0.021 microcatheter. The objective of this study was to evaluate the safety and effectiveness of Silk Vista systems for treating cerebral aneurysms.

Methods: This prospective observational study included 25 consecutive patients with 27 wide-necked unruptured aneurysms treated with SILK Vista who were retrospectively analyzed for safety and efficacy.

Results: Endovascular treatment was successfully performed in all patients. The final morbidity and mortality rates were both 0.0%. Short-term (3–5 months) angiographic follow-up revealed 21 complete occlusions and 6 near-complete occlusions. No significant parent artery stenosis was observed.

Conclusions: This report demonstrates the efficacy of Silk Vista in treating brain aneurysms, although longer experiences should be carried out to confirm our results.

Triggering of Carotid Sinus Reflex during Deployment of the Flow-diverter Device

The carotid sinus reflex (CSR) is a rare complication of the Pipeline Embolization Device (PED) deployment. No study has assessed the potential risk factors in a case series. The purpose of this study was to examine CSR triggering during PED deployment. Thirty-seven consecutive patients who underwent PED deployment were included. All procedures were performed under local anesthesia with mild sedation. We retrospectively analyzed patient characteristics, PED deployment time, and vital signs during the procedure. The vital signs included the pulse rate (PR) and systolic blood pressure (SBP) obtained at three timepoints (pre-deployment, during deployment, post-deployment). We examined the triggering of the CSR during PED deployment by comparing the vital signs at the three timepoints. Moreover, risk factors for CSR were analyzed with univariate analysis. The patients’ average age was 66.3 years. The average size of the aneurysm was 18.0 mm. Six patients (16.2%) showed a decline in the SBP or PR defined as CSR. One patient had a transient cardiac arrest and two had severe transient bradycardia. Deployment into the ophthalmic segment of the internal carotid artery (C2 segment) aneurysm (p = 0.022), prolonged PED deployment time more than 14.5 minutes (p = 0.005), and an acute angle of the anterior genu less than 51.5 degrees (p = 0.005) were risk factors in triggering CSR. CSR may be triggered during PED deployment under local anesthesia with mild sedation. Deployment to the C2 segment aneurysm, prolonged PED deployment time, and an acute angle of the anterior genu were associated with CSR triggering.

Retrospective analysis of intracranial aneurysms after flow diverter treatment including color-coded imaging (syngo iFlow) as a predictor of aneurysm occlusion

PURPOSE

Flow Diverters (FD) have immensely extended the treatment of cerebral aneurysms in the past years. Complete aneurysm occlusion is a process that often takes a certain amount of time and is usually difficult to predict. Our aim was to investigate different syngo iFlow parameters in order to predict aneurysm occlusion.

METHODS

Between 2014 and 2018 patients with unruptured cerebral aneurysms treated with a FD were reviewed. Aneurysm occlusion and complication rates have been assessed.In addition, various quantitative criteria were assessed using syngo iFlow before, after the intervention, and after short and long-term digital subtraction angiography (DSA).

RESULTS

A total of 66 patients hosting 66 cerebral aneurysms were included in this study. 87.9% (n = 58) aneurysms in the anterior and 12.1% (n = 8) in the posterior circulation were treated. Adequate aneurysm occlusion at long-term follow-up (19.05 ± 15.1 months) was achieved in 90.9% (n = 60). Adequately occluded aneurysm revealed a significantly greater peak intensity delay (PI-D, p = 0.008) and intensity decrease ratio (ID-R, p < 0.001) compared to insufficiently occluded aneurysms. Increased intra-aneurysmal contrast agent intensity (>100%) after FD implantation resulted in an ID-R < 1, which was associated with aneurysm growth during follow-up DSA. Retreatment with another FD due to foreshortening and/or aneurysm growth was performed in 10.6% (n = 7). Overall morbidity and mortality rates were 1.5% (n = 1) and 0%.

CONCLUSION

The applied syngo iFlow parameters were found to be useful in predicting adequate aneurysm occlusion and foresee aneurysm growth, which might indicate the implantation of another FD.

Torsional Characterization of Braided Flow Diverter Stents : A New Method to Evaluate Twisting Phenomenon

PURPOSE

In the interventional treatment of cerebral aneurysms, flow diverter (FD) stents have played a significant role for more than a decade. Many studies have shown good aneurysm occlusion rates and low complication profiles. However, feared complications include acute thrombotic vessel occlusion due to stenotic deformation of the FD during release, the so-called twisting. This work investigates the behavior of different stent types to causative torsion forces in a mechanical model.

MATERIALS AND METHODS

Torsion characterization equipment was custom built, and two different FD stents (Derivo, Acandis and P64, Phenox) with n = 3 were tested. One end of the FD was fixed while the other end was twisted while measuring the torsion force.

RESULTS

In torsional force vs. the twisting angle graph, a very sharp decrease and increase in force was recorded when the stent collapsed or reopened, respectively, making it possible to characterize for twisting. All six devices showed partial/complete collapse on torsion and showed significant delayed reopening on untwisting. Interestingly on repeated testing, the stent collapsed at earlier angles, probably due to microscopic material defects. Slight variations between stents of the same type suggest that more extensive data sets are needed.

CONCLUSIONS

We report a new method to characterize torsion for braided FD stents, which is reliable and reproducible. Additionally, the delayed reopening and the tendency to collapse at earlier angles on consequent testing maneuvers can be significant for clinical usage.

Delayed rupture of intracranial aneurysms after placement of intra-luminal flow diverter

BACKGROUND

Though flow diverter is a safe and efficient modality, some patients can experience delayed aneurysmal rupture. The mechanism of delayed rupture is still obscure to us.

METHODS

We performed a systematic search in the PubMed database for patients with delayed rupture of intracranial aneurysms after flow diverter placement.

RESULTS

A total of 36 articles reporting on 60 patients were included in the final analysis. Of the 49 patients with description of presenting symptoms, six (12.2%) patients were incidentally diagnosed, 39 (87.8%) patients were admitted for aneurysmal rupture or mass effect. Multiple flow diverters were used in 38.3% (18/47) of the patients. Coil assistance was applied in 13.0% (7/54) of the patients. Delayed aneurysmal rupture led to intracranial hemorrhage or carotid-cavernous sinus fistula (CCF) in 76.8% (43/56) and 23.2% (13/56) of the patients, respectively. Of the 55 patients with description of outcome, 14 (25.5%) patients achieved good recovery, one (1.8%) patient was severely disabled, 40 (72.7%) patients died. All of the patients in the CCF group survived and experienced good recovery.

CONCLUSION

Increased intra-aneurysmal pressure, destabilization of the aneurysm wall by intra-aneurysmal thrombus, persistent residual intra-aneurysmal flow, characteristics of the specific aneurysm, and mechanical injury by the flow diverter might conjointly contribute to the final delayed rupture. There has been no established preventive measure to decrease the incidence of delayed rupture yet. The treatment and outcome depend on the presentation of delayed rupture. Patients presenting with aneurysm-related intracranial hemorrhage have a dismal outcome. Those presenting with CCFs usually have a satisfactory recovery.

Failure of Flow Diverter Therapy: Predictors and Management Strategies

Flow diversion is a safe and effective treatment for many types of brain aneurysms. Even so, there remain some aneurysms that persist despite initial treatment. In studies with the longest follow-up (5 yr), at least 5% of aneurysms persist with this treatment modality. As the cumulative experience and clinical indications for flow diversion continue to expand, the anatomic and functional characteristics that are associated with aneurysm persistence are increasingly described. Identification of these factors preoperatively can help to guide initial treatment decisions, enhance monitoring protocols in the follow-up period, and establish best practices for re-treatment when necessary. Herein, we review published clinical series and provide examples to highlight variables implicated in aneurysm persistence after treatment with flow diversion.

Pipeline Embolization Device With Adjunctive Coils for the Treatment of Unruptured Large or Giant Vertebrobasilar Aneurysms: A Single-Center Experience

Objective: To evaluate effectiveness and safety of Pipeline embolization device (PED) for large or giant verterbrobasilar aneurysms (LGVBAs), and to compare the therapeutic effects of PED with and without adjunctive coils. Methods: We retrospectively analyzed 21 cases of unruptured LGVBAs who were treated in our hospital with PED. These cases were divided into "PED group" and "PED with adjunctive coils group." We compared the aneurysm characteristics and treatment outcomes between the two groups. Results: The overall neurological complication rate was 28.6% (6/21) and the mortality rate was 4.8% (1/21). There were 12 patients in the PED group and nine in the PED with adjunctive coils group. There were no significant differences in age, smoking, hypertension, aneurysm size, aneurysm location, or operation time between the two groups. The complete aneurysm embolization rate and favorable outcome rate (modified Rankin Scale = 0,1) of the PED with adjunctive coils group was 78% (7/9) and 100% (9/9), respectively, which were both better compared with the PED group with 63.6% (7/11) and 83% (10/12), respectively. However, these differences were not statistically significant. Conclusion: The effectiveness and safety of PED for LGVBAs is acceptable. Treatment results did not differ between the PED and PED with adjunctive coils groups; therefore, whether coils should be used may depend the operator. Our results suggest that correct use of the coils does not increase complications. We suggest that PED with adjunctive coils should be used for some selected LGVBAs.

Delayed Proximal Flow Diverting Stent Migration in a Ruptured Intracranial Aneurysm: A Case Report

A flow diverter can be used to treat a ruptured aneurysm, especially during complicated cases for endovascular or open microsurgical procedures. However, some complications have been reported such as occlusion of side branches or perforating arteries, stent migration or improper stent position, re-rupture of the aneurysm, and in-stent thrombosis. A 38-year-old man diagnosed with a ruptured left supraclinoid aneurysm was treated with a Pipeline embolization device. Despite adequate stent coverage of the aneurysmal neck, delayed proximal migration was seen in follow-up imaging. To our knowledge, proximal migration of the stent mostly happens intraoperatively due to an undersized stent or excessive stretching. We report a case of delayed proximal flow diverter stent migration.

Use of Contralateral Trans-Anterior Communicating Artery Snare to Rescue Lost Access to a Pipeline Embolization Device Unsheathed in an Aneurysm

Objective

A pipeline embolization device (PED; Medtronic, Minneapolis, MI, USA) is a new vascular reconstruction device used to treat large internal carotid artery (ICA) aneurysms in Japan. We herein present a PED-related complication and describe its rescue strategy. Rescue therapy using a snare via the posterior communicating artery from the contralateral side has already been reported. However, this is the first report of therapy via the anterior communicating artery (AcomA).

Case Presentation

A 49-year-old woman underwent vascular reconstruction with a PED for a large cavernous ICA aneurysm. During the placement of the PED, the proximal side of the PED slipped into the aneurysm. It was impossible to enter the true lumen of the PED from the proximal side because the orifice of the stent faced the aneurysmal wall. Contralateral trans-AcomA access to the PED was obtained through the distal ICA. The microwire from the distal ICA was connected with Goose Neck snares (Medtronic) from the proximal ICA. Pulling the snares to the proximal side, the PED was straightened and distal access was regained. Another PED was deployed such that it overlapped with the first PED to achieve vascular reconstruction. The patient finally recovered from aphasia, but paralysis of the right upper limb remained after rehabilitation.

Conclusion

If the stent slips into the aneurysm, distal access through the true stent lumen may be very difficult. We presented a rescue technique for this complication, through the AcomA from the contralateral side.

The POP (Pull on Pipe) Maneuver: A Technical Note for Rescuing a Prolapsed Pipeline Device

BACKGROUND

Flow diverters have revolutionized the treatment of large aneurysms. However, prolapse of the device into the aneurysm is a known complication that may have fatal consequences.

CASE

We present a case of a 21-year-old male with a giant aneurysm located in the cavernous segment of the right internal carotid artery. After Pipeline Embolization Device (PED) deployment, while retrieving the PED wire, the proximal end of the stent shortened, resulting in prolapse of the device into the aneurysm. We utilized the Pull on Pipe (POP) maneuver, characterized by the deployment of a second PED inside the lumen of the prolapsed device and gentle traction to restore the initial flow diverter into its proper position. The maneuver also allows for the immediate deployment of the second PED to improve proximal purchase and overall construct stability.

CONCLUSION

The POP maneuver is a novel strategy for salvaging herniated flow diverters and establishing a more stable PED construct.

Flow diverter stent for treatment of cerebral aneurysms: A report of 130 patients with 134 aneurysms

Background

This study aims to report our experience with cerebral aneurysms, which may improve in the treatment with the flow-diverter stent and follow up.

Methods

This study was conducted in a consecutive series of 130 patients. 134 procedures were performed for treating these patients in Hanoi Medical University Hospital and Bach Mai Hospital from January 2012 to April 2017. 143 flow diverter stents (Pipeline, FRED and SILK) were used. Aneurysm morphology, stent patency and cerebral parenchyma before and after intervention were analyzed on images of digital subtraction angiography (DSA), computed tomography (CT) and magnetic resonance (MR). The follow-up data after 3-6 months and 12 months were recorded.

Results

In 130 patients (31 men, 99 women), aneurysms of internal carotid artery were mostly common (92.6%), especially in cavernous (35.1%) and in para-ophthalmic (40.3%) segments. 83 cases (61.9%) had wide-neck aneurysms, and 16 cases (11.9%) had multiple aneurysms, and only 5 cases (3.7%) had blister-liked aneurysms. Endovascular treatment was successfully performed at rate of 94.8%. In 3 patients, the stent could not be delivered. Mortality and morbidity rates were 1.5% and 3.7%, respectively. MRI and MSCT follow-up at 3 months showed complete or incomplete occlusions of aneurysms was 7.4% or 17.5%, respectively. 3 patients experienced a thromboembolic event (4.3%).

Conclusions

Intracranial aneurysms of cavernous and para-ophthalmic segments of internal carotid artery are mostly common with wide-neck and multi aneurysms. Deployment of flow diverter stent is safe and effective with high rate of successful and low procedural complications.

Pipeline Embolization Device for Treatment of Extracranial Internal Carotid Artery Pseudoaneurysms: A Multicenter Evaluation of Safety and Efficacy

BACKGROUND

There is a paucity of literature regarding treatment options for extracranial pseudoaneurysms of the internal carotid artery (ICA). To date, Pipeline Embolization Device (PED; Medtronic Inc) use for the treatment of extracranial pseudoaneurysms of the ICA has only been reported from single-center case series.

OBJECTIVE

To evaluate the safety and efficacy of PED for the treatment of extracranial ICA pseudoaneurysms.

METHODS

This is a multicenter retrospective study involving 6 high-volume tertiary academic institutions in the United States. We analyzed patients with extracranial ICA pseudoaneurysms treated with PED between January 1, 2011, and January 1, 2019. Clinical assessment was performed pre- and postintervention using the modified Rankin Scale (mRS) and National Institution of Health Stroke Scale (NIHSS) at a minimum of 4-mo follow-up.

RESULTS

A total of 28 pseudoaneurysms with a mean diameter of 17.7 mm (range: 4.1-52.5 mm) were treated with PED in 24 patients at 6 participating centers. The mean age was 52.1 yr (17-73) ± 14.3 with 14 females and 10 males. At a mean of 21-mo (range 4-66 mo) follow-up, complete occlusion was achieved in 89% (n = 25/28), with near-complete occlusion (&gt;90% occlusion) in the remainder. There were no periprocedural complications. Postprocedure NIHSS was 0 in 88% (n = 21/24) and 1 in 12% (n = 3/24) of patients, and mRS was 0 in 83% (n = 20/24) and 1 in 17% (n = 4/24) of patients.

CONCLUSION

The treatment of extracranial ICA pseudoaneurysms with PED is safe and effective in selected patients. Randomized controlled trials and prospective cohort studies are needed to establish the role of flow diversion for ICA pseudoaneurysms.

The Importance of Wall Apposition in Flow Diverters

BACKGROUND

It is assumed that high pore densities in flow diverters (FDs) are beneficial for intracranial aneurysm (IA) healing. However, various animal studies are not conclusive on the issue, suggesting that other factors are in play. One important factor might be wall apposition.

OBJECTIVE

To (1) determine the relationship between FD pore density and aneurysm occlusion, and (2) determine the relationship between FD wall apposition and aneurysm occlusion.

METHODS

Saccular aneurysms were microsurgically created in the aorta of 36 Wistar rats. Twelve rats received a low pore density FD (10 pores/mm2), 12 rats received a high pore density FD (23 pores/mm2), and the remaining 12 rats served as a control group. Six animals from each group were sacrificed 1 and 3 mo after surgery. We determined aneurysm occlusion, the number of struts not in contact with the aorta wall, and the average distance from malapposed struts to aorta wall through histology.

RESULTS

No significant differences were found in aneurysm occlusion between the low pore density and high pore density groups (P > .05) after 1 and 3 mo of follow-up. The average number of malapposed struts was lower for the occluded aneurysm group (4.4 ± 1.9) compared to the nonoccluded aneurysm group (7.7 ± 2.6, P < .01). The average distance between malapposed struts and parent artery wall was lower for the occluded aneurysm group (33.9 μm ± 11.5 μm) than for the nonoccluded aneurysm group (48.7 μm ± 18.8 μm, P < .05).

CONCLUSION

Wall apposition is more important than pore density for aneurysm occlusion.

Introduction: History and Development of Flow Diverter Technology and Evolution

The introduction of flow diverter technology to the field of neurointervention has revolutionized the treatment of intracranial aneurysms. The therapy approach has shifted from intrasaccular aneurysm treatment to exclusion of the aneurysm from the blood circulation with remodeling of the parent artery. Previously, “difficult”-to-treat aneurysms including fusiform and blister aneurysms, but also aneurysms arising from a diseased vessel segment, can now be safely and permanently treated with flow diverters.

 A little over a decade ago, after extensive bench testing and refinement of the flow diverter concept, the device was eventually available for clinical use and today it has become a standard treatment for intracranial aneurysms. Currently, United States Food and Drug Administration (FDA)-approved flow diverters are the Pipeline Embolization Device (Medtronic) and the Surpass Streamline Flow Diverter (Stryker).

 The devices can either be delivered or deployed via a standard femoral artery approach or a radial artery approach. Other considerations for catheter setup and device deployment strategies depending on aneurysm location or vessel anatomy are described.

Efficacy and safety of the dual-layer flow-diverting stent (FRED) for the treatment of intracranial aneurysms

Purpose

To describe the efficacy and complications of treating cerebral aneurysms with the Flow Re-direction Endoluminal Device (FRED) and to identify predictors for aneurysm occlusion.

Methods

A prospective observational registry including all consecutive aneurysms treated with FRED between December 2015 and July 2018 was designed in one therapeutic neuroangiography department. The primary endpoint for treatment efficacy was complete or near-complete occlusion (O’Kelly–Marotta (OKM) C–D), assessed by three-dimensional digital subtraction angiography. Major (all symptomatics) and minor complications were described and those with modified Rankin Scale scores 3–6 were considered clinically relevant. Univariate and multivariate analyses were performed to identify predictors of efficacy.

Results

A total of 185 aneurysms were analyzed in 150 patients (mean age 54.3±11.5 years). Mean follow-up was 18.99±11.32 months (range 0–43). Efficacy was evaluated in 156 (84.32%) cases: 132 (84.6%) had OKM C–D occlusion, 31/47 (66%) within the first year and 101/109 (92.7%) later on. Major complications were observed in 12 (6.5%) cases: three strokes (one transient ischemic accident, two minor strokes), six intra-stent thrombosis, and three with bleeding, but only one (0.5%) was clinically relevant. Minor complications (all asymptomatic) were observed in 10 (5.4%) cases: three shortening/repositioning of stent; two arterial dissection, two arterial occlusion, and three intra-stent stenosis. Independent predictors of occlusion were immediate OKM grade B–C–D (OR 4.01, 95% CI 1.51 to 10.62), single aneurysm (OR 3.29, 95% CI 1.05 to 10.32), and small size aneurysm (OR 4.74, 95% CI 1.57 to 14.30).

Conclusion

The FRED stent fully complied with efficacy and safety requirements for treatment of intracranial aneurysms. Three predictors of aneurysm occlusion were identified.

Coiling as a Rescue Strategy for Flow Diverter Prolapse into a Giant Intracranial Aneurysm

BACKGROUND

Up to 3.2% of the adult population has an unruptured intracranial aneurysm (IA). Flow diversion is a relatively new treatment technique that is especially useful for large and morphologically unfavorable IAs.

METHODS

A previously healthy woman aged 32 years presented with a 6-month history of ptosis and ophthalmoplegia of the left eye. A magnetic resonance imaging scan revealed a giant left internal carotid artery aneurysm. She was admitted for treatment using flow diversion. After delivery of the flow diverter (FD), prolapse of the proximal end of the stent into the aneurysmal sac was observed. FD stabilization was achieved by deploying multiple coils through a previously placed microcatheter to push the prolapsed end away from the aneurysmal lumen.

RESULTS

The patient had a favorable outcome, with reduction of preoperative mass effect symptoms and complete obliteration of the aneurysm persisting at the 3-month follow-up.

CONCLUSIONS

Giant IAs remain one of the most daunting clinical problems to treat. FD displacement is a rare (0.5%-0.75%) and possibly fatal complication. Currently, no clinical guidelines exist for its management. Adjunctive coiling is a possible rescue strategy for stabilizing an FD that foreshortened and prolapsed into the aneurysmal sac. Further studies are needed to identify the best approach to this complication.

Regrowth of a Large Intracranial Aneurysm after On-Label Use of the Pipeline Embolization Device

Despite the widespread use of the pipeline embolization device (PED), no complete aneurysm regrowth after its placement has been reported in the literature. We report the first case of aneurysm regrowth after the initial follow-up angiography demonstrating near-complete occlusion of the aneurysm and remodeling of the vessel with on-label PED use for a large 20 mm × 24 mm × 22 mm (width × depth × height) cavernous segment internal carotid artery (ICA) aneurysm. The patient was treated with two overlapping PED (4.5 mm × 20 mm and 5 mm × 20 mm). Follow-up angiogram at 4 months after treatment demonstrated remodeling of the ICA with a small residual component measuring approximately 7 mm × 8 mm × 7 mm. However, at 10 months after treatment, there was a complete regrowth of the aneurysm with interval growth, now measuring 25 mm × 28 mm × 18 mm. Despite the high aneurysm occlusion rates reported with the PED, persistent aneurysm filling and aneurysm regrowth, although rare, should not be overlooked.

Deployment of flow diverter devices: prediction of foreshortening and validation of the simulation in 18 clinical cases

PURPOSE

Flow diverter (FD) devices show severe shortening during deployment in dependency of the vessel geometry. Valid information regarding the geometry of the targeted vessel is therefore mandatory for correct device selection, and to avoid complications. But the geometry of diseased tortuous intracranial vessels cannot be measured accurately with standard methods. The goal of this study is to prove the accuracy of a novel virtual stenting method in prediction of the behavior of a FD in an individual vessel geometry.

METHODS

We applied a virtual stenting method on angiographic 3D imaging data of the specific vasculature of patients, who underwent FD treatment. The planning tool analyzes the local vessel morphology and deploys the FD virtually. We measured in 18 cases the difference between simulated FD length and real FD length after treatment in a landmark-based registration of pre-/post-interventional 3D angiographic datasets.

RESULTS

The mean value of length deviation of the virtual FD was 2.2 mm (SD ± 1.9 mm) equaling 9.5% (SD ± 8.2%). Underestimated cases present lower deviations compared with overestimated FDs. Flow diverter cases with a nominal device length of 20 mm had the highest prediction accuracy.

CONCLUSION

The results suggest that the virtual stenting method used in this study is capable of predicting FD length with a clinically sufficient accuracy in advance and could therefore be a helpful tool in intervention planning. Imaging data of high quality are mandatory, while processing and manipulation of the FD during the intervention may impact the accuracy.

A rare complication of flow diverter: delayed migration causing aneurysm expansion and brainstem compression

Flow-diverting stents (FD) are admitted therapeutic devices for challenging aneurysms. Delayed migrations of FD remain exceptional, particularly with brainstem compression. We report a case of delayed migration of pipeline embolization device (PED) responsible of medulla oblongata compression due to expansion of posterior inferior cerebellar artery (PICA) aneurysm. This is the first report of brainstem compression due to delayed migration of FD. Among the seven previously reported cases of FD delayed migration, two led to death. Our case illustrates the importance of technical issues of stenting and the role of surgery facing the clinical emergency of vascular compression of lower brainstem. We wanted to warn neurosurgeons of this rare and delayed complication, which likely could become less exceptional with the increase of indications and utilizations of FD.

Endovascular management of spontaneous delayed migration of the flow-diverter stent

BACKGROUND AND PURPOSE

Spontaneous delayed migration of the flow-diverter stent (FD) is an unusual complication that can be fatal. The purpose of this study is to report our experience and review the literature for the management of delayed FD migration.

MATERIALS AND METHODS

Between November 2013 and June 2017, 122 patients treated by FD at our institution were enrolled. We also performed a comprehensive review of the literature.

RESULTS

Six patients (4.9%) were found to have spontaneous delayed migration of their FD. The device migrated proximally in 4 patients and distally in 2 patients. One patient had temporal lobe infarction due to stent migration, and another had subarachnoid haemorrhage (SAH). Three patients were treated with a 2nd or 3rd FD, while 2 were treated with stent-assisted coiling, and one was treated with sacrifice of the parent internal carotid artery. According to our results and the literature, the prevalence rate of delayed FD migration ranges from 2.2% to 4.9%, and the mortality and morbidity rate of delayed FD migration is 40%.

CONCLUSIONS

Neuro-interventionalists should be aware of this complication and be familiar with risk factors, preventive methods and treatment options. If there is any concern regarding the size or position of the FD, early imaging follow-up and endovascular treatment should be indicated.

Endovascular techniques for achievement of better flow diverter wall apposition

Flow diverter malapposition has been described as a technical complication during endovascular procedures and can be associated with, potentially delayed, life-threatening aneurysm rupture or ischemic events. We performed a retrospective review of our flow diverter database to identify all patients in whom device malapposition was detected on follow-up angiogram immediately after device deployment. Feasibility and technical success of different endovascular approaches aiming to correct the inadequate vessel wall apposition were evaluated. Successful endovascular techniques for manipulation of the flow diverter included use of wires, catheters and additional flow diverter/stent devices. In our practice, we found six successful endovascular techniques for device manipulation, which allowed us to safely achieve good flow diverter wall apposition.

A case of pipeline migration in the cervical carotid

Since its emergence in 2011, the pipeline flow diversion (PFD) has gained recognition in the treatment of certain intracranial aneurysms. However, early or delayed pipeline migration (PM) and micro-catheter/guidewire retention have been infrequently reported. We report a case of PM and shortening in the treatment of a left cervical internal carotid artery (LICA) aneurysm. A middle-aged African-American patient presents for an off-label PFD treatment of an incidental 21 × 23 mm aneurysm at the sub-petrous segment of the left ICA. While the patient remained completely neuro-intact, a 6 months follow-up angiogram revealed a persisting filling of the cervical aneurysm with a foreshortening of the pipeline by 1/3 of its original 30 mm size and proximal migration into the aneurysmal sac. We opted to watch the aneurysm within 6 months especially that the aneurysm was extra-cranial and because of the potential risks involved in trying to re-access the device.

Early Results in Flow Diverter Sizing by Computational Simulation: Quantification of Size Change and Simulation Error Assessment

BACKGROUND

Sizing of flow diverters (FDs) stent in the treatment of intracranial aneurysms is a challenging task due to the change of stent length after implantation.

OBJECTIVE

To quantify the size change and assess the error in length prediction in 82 simulated FD deployments.

METHODS

Eighty-two consecutive patients treated with FDs were retrospectively analyzed. Implanted FD length was measured from angiographic images and compared to the nominal sizes of the implanted device. Length change was obtained by subtracting the nominal length from the real length and dividing by the nominal length. Implanted devices were simulated on 3-dimensional models of each patient. Simulation error was obtained by subtracting real length from simulated length and dividing by the real length of the FD. Subanalysis was done using ANOVA. Statistical significance was set to P < .05, and bootstrap resampling was used.

RESULTS

When assessing the length change of the FD after implantation, changes of 30% in average and up to 80% with reference to the nominal length of the device were observed. The simulation results showed a lower error of 3.52% in average with a maximum of 30%. Paired t-test showed nonsignificant differences between measured and real length (P = .07, with the mean of differences at 0.45 mm, 95% confidence interval [-0.950 0.038]).

CONCLUSION

Nominal length is not an accurate sizing metric when choosing the size of an FD irrespective of the brand and manufacturer. Good estimation of the final length of the stent after deployment as expressed by an error of 3.5% in average.