A New Aneurysm Occlusion Classification after the Impact of Flow Modification

Evaluation of flow diverters for cerebral aneurysm therapy: recommendations for imaging analyses in clinical studies, endorsed by ESMINT, ESNR, OCIN, SILAN, SNIS, and WFITN

BACKGROUND

Multiple studies and meta-analyses have described the technical and clinical outcomes in large cohorts of aneurysm patients treated with flow diverters (FDs). Variations in evaluation methodology complicate making comparisons among studies, hinder understanding of the device behavior, and pose an obstacle in the assessment of further advances in FD therapy.

METHODS

A multidisciplinary panel of neurointerventionalists, imaging experts, and neuroradiologists convened with the goal of establishing consensus recommendations for the standardization of image analyses in FD studies.

RESULTS

A standardized methodology is proposed for evaluating and reporting radiological outcomes of FD treatment of intracranial aneurysms. The recommendations include general imaging considerations for clinical studies and evaluations of longitudinal changes, such as neointimal lining and stenosis. They cover standards for classification of aneurysm location, morphology, measurements, as well as the assessment of aneurysm occlusion, wall apposition, and neck coverage. These reporting standards further define four specific braid deformation patterns: foreshortening, fish-mouthing, braid bump deformation, and braid collapse, collectively termed 'F2B2'.

CONCLUSIONS

When widely applied, standardization of methods of measuring and reporting outcomes will help to harmonize the assessment of treatment outcomes in clinical studies, help facilitate communication of results among specialists, and help enable research and development to focus on specific aspects of FD techniques and technology.

Magnetic resonance perfusion imaging findings following flow diversion in patients with complex middle cerebral artery bifurcation aneurysms: a single-center analysis regarding the jailed cortical branches

BACKGROUND

Flow diverter (FD) devices provide a safe and effective treatment option especially for wide-necked intracranial aneurysms. One of the main concerns in patients treated with FD devices is patency of arterial branches jailed by the stent. However, there are no long-term data from magnetic resonance perfusion (MRP) studies regarding jailed branches. In this study we aimed to reveal the MRP findings in patients with jailed middle cerebral artery (MCA) cortical branches during long-term follow-up after flow diversion.

METHODS

Patients who underwent FD stent treatment for MCA aneurysms with a resulting jailed cortical branch were included. Follow-up clinical, angiographic, and MRP examination findings were recorded. Different MRP parameters were measured in the MCA territory regarding the jailed branches.

RESULTS

Eighteen patients treated endovascularly with flow diversion for a total of 20 MCA aneurysms were included. At angiographic follow-up (median 35 months, range 7-95 months) complete occlusion was observed in 13 (65%) aneurysms and partial occlusion was observed in 6 (30%). The mean transit time (MTT) prolongation, MTT ratio, time-to peak (TTP) prolongation, and TTP ratio were 1.34, 1.20, 1.18, and 1.06 s, respectively, when compared with the contralateral side in the MCA territory. MTT, TTP, and cerebral blood volume values of the patients showed statistically significant differences compared with the contralateral side (P<0.05).

CONCLUSIONS

Flow diversion treatment of complex bifurcation aneurysms can be effective and safe. MRP examination may reveal perfusion changes in the territory vascularized via a jailed branch, and these changes are rarely accompanied by clinical findings.

Endovascular treatment of middle cerebral artery aneurysms: current status and future prospects

Middle cerebral artery (MCA) aneurysms are complex and widely distributed throughout the course of the MCA. Various types of aneurysms can occur in the MCA. Ruptured as well as unruptured MCA aneurysms may require treatment to avoid bleeding or rebleeding. Currently, clipping is regarded as the first-line choice for the treatment of MCA aneurysms. However, endovascular treatment (EVT) is emerging as an alternative treatment in selected cases. EVT techniques vary. Therefore, it is necessary to review EVT for MCA aneurysms. In this review, the following issues were discussed: MCA anatomy and anomalies, classifications of MCA aneurysms, the natural history of MCA aneurysms, EVT status and principle, deployments of traditional coiling techniques and flow diverters (FDs), and deployments and prospects of intrasaccular flow disruptors and stent-like devices. According to the review and our experience, traditional coiling EVT is still the preferred therapy for most MCA aneurysms. FD deployment can be used in selective MCA aneurysms. Parent artery occlusion (PAO) can be used to treat distal MCA aneurysms. In addition, new devices can be used to treat MCA aneurysms, such as intrasaccular flow disruptors and stent-like devices. In general, EVT is gaining popularity as an alternative treatment option; however, there is still a lack of evidence regarding EVT, and longer-term data are not currently available for most EVT devices.

Surpass Intracranial Aneurysm Embolization System Pivotal Trial to Treat Large or Giant Wide-Neck Aneurysms - SCENT: 3-year outcomes

BACKGROUND

To report the 3-year safety and effectiveness of the Surpass Streamline flow diverter in the SCENT trial (Surpass Intracranial Aneurysm Embolization System Pivotal Trial to Treat Large or Giant Wide-Neck Aneurysms).

METHODS

The Surpass Streamline flow diverter device was evaluated in a multicenter, prospective, single-arm, non-randomized interventional trial including patients with uncoilable or previously treated but failed aneurysms of the intracranial internal carotid artery. 3-year outcomes were tabulated with descriptive statistics and compared with 1-year outcomes.

RESULTS

Of 180 patients in the modified intent-to-treat (mITT) cohort, 36-month clinical and angiographic follow-up was available in 134 and 117 cases, respectively. Effectiveness endpoint of complete aneurysm occlusion without clinically significant stenosis or retreatment was met in 71.8% (79/110, 95% CI 62.4% to 80.0%) of cases. Safety composite endpoint was 12.2% (22/180) over the 3-year period, with two major safety events (ipsilateral ischemic strokes) occurring between 12-36 months. Complete aneurysm occlusion was noted in 77.8% (91/117), and 99.1% (116/117) of the patients demonstrated adequate aneurysm occlusion (complete occlusion or neck residual). There were four cases (2.2%) of aneurysm rupture, all occurring within the first month of the index procedure. Target aneurysm retreatment rate was 2.8% (5/180).

CONCLUSION

The present findings support the long-term safety and effectiveness of the Surpass Streamline flow diverter device.

TRIAL REGISTRATION

NCT01716117.

Management of aneurysmal recurrence after Woven EndoBridge (WEB) treatment

BACKGROUND

Around 10% of Woven EndoBridge device (WEB)-treated intracranial aneurysms will need retreatment, and it is generally believed to be more challenging than retreatment after an initial coiling. We aim to report retreatment strategies and outcomes after initial WEB embolizations.

METHODS

Databases from four treatment centers, containing consecutive aneurysms treated with a WEB between 2013 and 2022, were reviewed. Demographics, aneurysm characteristics, retreatment strategies and outcomes were collected and analyzed.

RESULTS

From a 756 WEB database, 57 aneurysms were included. The global retreatment rate was 7.5% (95% CI 5.6% to 9.4%). The retreatment rate was significantly higher in the ruptured compared with the unruptured population (13% vs 3.9%, respectively, P<0.0001). Aneurysms were retreated on average 21.2 months after the initial WEB treatment (range 4.8-70 months). Surgery was performed in 11% and endovascular treatment in 89% of cases, consisting of flow diversion (48%), stent-assisted coiling (30%), coiling (12%), and second WEB placement (10%). Imaging follow-up was available in 88% of all WEB retreatments (50/57) (average 17 months, 49% digital subtraction angiography), demonstrating complete occlusion in 56% and 'adequate' occlusion in 88%. Morbidity was 5.3% (95% CI 0% to 12.0%) and mortality 0%. No patient experienced rebleeding during the follow-up period.

CONCLUSION

The retreatment rate after an initial WEB treatment seems to compare favorably with that of coiling. Endovascular treatment of recurrence following WEB implantation is feasible in most situations; it generally requires the use of a stent and leads to a high rate of satisfactory occlusion.

A comparison of treating physician versus independent core lab assessments of post-aneurysm treatment imaging outcomes: an analysis of prospectively collected data from a randomized trial

OBJECTIVE

Aneurysm occlusion has been used as surrogate marker of aneurysm treatment efficacy. Aneurysm occlusion scales are used to evaluate the outcome of endovascular aneurysm treatment and to monitor recurrence. These scales, however, require subjective interpretation of imaging data, which can reduce the utility and reliability of these scales and the validity of clinical studies regarding aneurysm occlusion rates. Use of a core lab with independent blinded reviewers has been implemented to enhance the validity of occlusion rate assessments in clinical trials. The degree of agreement between core labs and treating physicians has not been well studied with prospectively collected data.

METHODS

In this study, the authors analyzed data from the Hydrogel Endovascular Aneurysm Treatment (HEAT) trial to assess the interrater agreement between the treating physician and the blinded core lab. The HEAT trial included 600 patients across 46 sites with intracranial aneurysms treated with coiling. The treating site and the core lab independently reviewed immediate postoperative and follow-up imaging (3-12 and 18-24 months, respectively) using the Raymond-Roy occlusion classification (RROC) scale, Meyer scale, and recanalization survey. A post hoc analysis was performed to calculate interrater reliability using Cohen's kappa. Further analysis was performed to assess whether degree of agreement varied on the basis of various factors, including scale used, timing of imaging, size of the aneurysm, imaging modality, location of the aneurysm, dome-to-neck ratio, and rupture status.

RESULTS

Minimal interrater agreement was noted between the core lab reviewers and the treating physicians for assessing aneurysm occlusion using the RROC grading scale (k = 0.39, 95% CI 0.38-0.40) and Meyer scale (k = 0.23, 95% CI 0.14-0.38). The degree of agreement between groups was slightly better but still weak for assessing recanalization (k = 0.45, 95% CI 0.38-0.52). Factors that significantly improved degree of agreement were scales with fewer variables, greater time to follow-up, imaging modality (digital subtraction angiography), and wide-neck aneurysms.

CONCLUSIONS

Assessment of aneurysm treatment outcome with commonly used aneurysm occlusion scales suffers from risk of poor interrater agreement. This supports the use of independent core labs for validation of outcome data to minimize reporting bias. Use of outcome tools with fewer point categories is likely to provide better interrater reliability. Therefore, the outcome assessment tools are ideal for clinical outcome assessment provided that they are sensitive enough to detect a clinically significant change.

Safety and efficacy of flow diverter stents in the treatment of middle cerebral artery aneurysms: a single-center experience and follow-up data

PURPOSE

This study aims to evaluate the safety and efficacy of flow diverters (FDs) in the treatment of middle cerebral artery (MCA) aneurysms and share the follow-up (F/U) results.

METHODS

The treatment and F/U results of 76 MCA aneurysms treated with the flow re-direction endoluminal device (FRED), FRED Jr., and pipeline embolization device (PED) FD stents were evaluated retrospectively. The aneurysm occlusion rates were compared between FDs, and the integrated and jailed branches were evaluated through follow-ups. The oversizing of the stent was compared between occluded/non-occluded aneurysms and integrated branches.

RESULTS

The mean F/U duration was 32 ± 6.3 months, and the mean aneurysm diameter was 4.45 mm. A total of 61 (80.3%) aneurysms were wide-necked; 73 (96.1%) were saccular; 52 (68.4%) were located at the M1 segment; and 36 (45.6%) FREDs, 23 (29.1%) FRED Jr.s, and 19 (24.1%) PEDs were used for treatment. The overall occlusion rates for the 6-, 12-, 24-, 36-, and 60-month digital subtraction angiographies were 43.8%, 63.5%, 73.3%, 85.7%, and 87.5% respectively. The last F/U occlusion rates were 67.6% for FRED, 66.7% for PED, and 60.6% for FRED Jr. (P = 0.863). An integrated branch was covered with an FD during the treatment of 63 (82.8%) aneurysms. A total of six (10%) of the integrated branches were occluded without any symptoms at the last F/U appointment. The median oversizing was 0.45 (0-1.30) for occluded aneurysms, and 0.50 (0-1.40) for non-occluded aneurysms (P = 0.323). The median oversizing was 0.70 (0.45-1.10) in occluded integrated branches and 0.50 (0-1.40) in non-occluded branches (P = 0.131). In-stent stenosis was seen in 22 (30.1%) of the stents at the 6-month F/U and in only 2 (4.7%) at the 24-month F/U. Thus, none of the patients had any neurological deficits because of the in-stent stenosis. Severe in-stent stenosis was seen in two stents.

CONCLUSION

MCA aneurysms tend to be complex, with integrated branches and potentially wide necks. FD stents are safe and effective in the treatment of MCA aneurysms, and the patency of the side and jailed branches is preserved in most cases. Higher occlusion and lower in-stent stenosis rates are seen with longer F/U durations.

Prospective study on embolization of intracranial aneurysms with the pipeline device (PREMIER study): 3-year results with the application of a flow diverter specific occlusion classification

BACKGROUND

The pipeline embolization device (PED; Medtronic) has presented as a safe and efficacious treatment for small- and medium-sized intracranial aneurysms. Independently adjudicated long-term results of the device in treating these lesions are still indeterminate. We present 3-year results, with additional application of a flow diverter specific occlusion scale.

METHODS

PREMIER (prospective study on embolization of intracranial aneurysms with pipeline embolization device) is a prospective, single-arm trial. Inclusion criteria were patients with unruptured wide-necked intracranial aneurysms ≤12 mm. Primary effectiveness (complete aneurysm occlusion) and safety (major neurologic event) endpoints were independently monitored and adjudicated.

RESULTS

As per the protocol, of 141 patients treated with a PED, 25 (17.7%) required angiographic follow-up after the first year due to incomplete aneurysm occlusion. According to the Core Radiology Laboratory review, three (12%) of these patients progressed to complete occlusion, with an overall rate of complete aneurysm occlusion at 3 years of 83.3% (115/138). Further angiographic evaluation using the modified Cekirge-Saatci classification demonstrated that complete occlusion, neck residual, or aneurysm size reduction occurred in 97.1%. The overall combined safety endpoint at 3 years was 2.8% (4/141), with only one non-debilitating major event occurring after the first year. There was one case of aneurysm recurrence but no cases of delayed rupture in this series.

CONCLUSIONS

The PED device presents as a safe and effective modality in treating small- and medium-sized intracranial aneurysms. The application of a flow diverter specific occlusion classification attested the long-term durability with higher rate of successful aneurysm occlusion and no documented aneurysm rupture.

TRIAL REGISTRATION

NCT02186561.

First clinical multicenter experience with the new Pipeline Vantage flow diverter

BACKGROUND

Flow diversion is an innovative and increasingly used technique for the treatment of intracranial aneurysms. New flow diverters (FDs) are being introduced to improve the safety and efficacy of this treatment. The aim of this study was to assess the safety, feasibility, and efficacy of the new Pipeline Vantage (PV) FD.

METHODS

Patients with intracranial aneurysms treated with the PV at 10 international neurovascular centers were retrospectively analyzed. Patient and aneurysm characteristics, procedural parameters, complications, and the grade of occlusion were assessed.

RESULTS

60 patients with 70 aneurysms (5.0% with acute hemorrhage, 90.0% located in the anterior circulation) were included. 82 PVs were implanted in 61 treatment sessions. The PV could be successfully implanted in all treatments. Additional coiling was performed in 18.6%, and in-stent balloon angioplasty (to enhance the vessel wall apposition) in 24.6%. Periprocedural technical complications occurred in 24.6% of the treatments, were predominantly FD deployment problems, and were all asymptomatic. The overall symptomatic complication rate was 8.2% and the neurological symptomatic complication rate was 3.3%. Only one symptomatic complication was device-related (perforator artery infarctions leading to stroke). After a mean follow-up of 7.1 months, the rate of complete aneurysm occlusion was 77.9%. One patient (1.7%) died due to aneurysmal subarachnoid hemorrhage which occurred before treatment, unrelated to the procedure.

CONCLUSIONS

The new PV FD is safe and feasible for the treatment of intracranial aneurysms. The short-term occlusion rates are promising but need further assessment in prospective long-term follow-up studies.

Triple therapy versus dual-antiplatelet therapy for dolichoectatic vertebrobasilar fusiform aneurysms treated with flow diverters

Background

Dolichoectatic vertebrobasilar fusiform aneurysms (DVBFAs) have poor natural history when left untreated and high morbimortality when treated with microsurgery. Flow diversion (FD) with dual-antiplatelet therapy (DAPT) is feasible but carries high risk of perforator occlusion and progression of brainstem compression. Elaborate antithrombotic strategies are needed to preserve perforator patency while vessel remodeling occurs. We compared triple therapy (TT (DAPT plus oral anticoagulation)) and DAPT alone in patients with DVBFAs treated with FD.

Methods

Retrospective comparison of DAPT and TT in patients with DVBFAs treated with FD at eight US centers.

Results

The groups (DAPT=13, TT=14) were similar in age, sex, clinical presentation, baseline disability, and aneurysm characteristics. Radial access use was significantly higher in the TT group (71.4% vs 15.3%; P=0.006). Median number of flow diverters and adjunctive coiling use were non-different between groups. Acute ischemic stroke rate during the oral anticoagulation period was lower in the TT group than the DAPT group (7.1% vs 30.8%; P=0.167). Modified Rankin Scale score decline was significantly lower in the TT group (7.1% vs 69.2%; P=0.001). Overall rates of hemorrhagic complications (TT, 28.6% vs DAPT, 7.7%; P=0.162) and complete occlusion (TT, 25% vs DAPT, 54.4%; P=0.213) were non-different between the groups. Rate of moderate-to-severe disability at last follow-up was significantly lower in the TT group (21.4% vs 76.9%; P=0.007).

Conclusions

Patients with DVBFAs treated with FD in the TT group had fewer ischemic strokes, less symptom progression, and overall better outcomes at last follow-up than similar patients in the DAPT group.

Predictors of incomplete aneurysm occlusion after treatment with the Pipeline Embolization Device: PREMIER trial 1 year analysis

BACKGROUND

Flow diverters have revolutionized the treatment of intracranial aneurysms. Nevertheless, some aneurysms fail to occlude with flow diversion. The Prospective Study on Embolization of Intracranial Aneurysms with the Pipeline Device (PREMIER) was a prospective, multicenter and single-arm trial of small and medium wide-necked unruptured aneurysms. In the current study, we evaluate the predictors of treatment failure in the PREMIER cohort.

METHODS

We analyzed PREMIER patients who had incomplete occlusion (Raymond-Roy >1) at 1 year angiographic follow-up and compared them with those who achieved Raymond-Roy 1, aiming to identify predictors of treatment failure.

RESULTS

25 aneurysms demonstrated incomplete occlusion at 1 year. There was a median reduction of 0.9 mm (IQR 0.41-2.43) in maximum diameter between pre-procedure and 1 year measurements, with no aneurysmal hemorrhage. Patients with incomplete occlusion were significantly older than those with complete occlusion (p=0.011). Smoking (p=0.045) and C6 segment location (p=0.005) were significantly associated with complete occlusion, while location at V4 (p=0.01) and C7 (p=0.007) and involvement of a side branch (p<0.001) were significantly associated with incomplete occlusion. In multivariable logistic regression, significant predictors of incomplete occlusion were non-smoker status (adjusted OR 4.49, 95% CI 1.11 to 18.09; p=0.03) and side branch involvement (adjusted OR 11.68, 95% CI 3.84 to 35.50; p<0.0001), while C6 location had reduced odds of incomplete occlusion (adjusted OR 0.29, 95% CI 0.10 to 0.84; p=0.02).

CONCLUSIONS

The results of our study are consistent with previous retrospective series and warrant consideration for technique adaptations to achieve higher occlusion rates. Further follow-up is needed to assess progression of aneurysm occlusion and clinical behavior in these cases.

Safety and Efficacy of the FRED Jr Flow Re-Direction Endoluminal Device for Intracranial Aneurysms: Retrospective Multicenter Experience With Emphasis on Midterm Results

Background and Purpose: Flow diversion is increasingly used as an endovascular treatment for intracranial aneurysms. In this retrospective multicenter study, we analyzed the safety and efficacy of the treatment of intracranial, unruptured, or previously treated but recanalized aneurysms using Flow Re-Direction Endoluminal Device (FRED) Jr with emphasis on midterm results.

Materials and Methods: Clinical and radiological records of 150 patients harboring 159 aneurysms treated with FRED Jr at six centers between October 2014 and February 2020 were reviewed and consecutively included. Clinical outcome was measured by using the modified Rankin Scale (mRS). Anatomical results were assessed according to the O'Kelly-Marotta (OKM) scale and the Cekirge-Saatci Classification (CSC) scale.

Results: The overall complication rate was 24/159 (16%). Thrombotic-ischemic events occurred in 18/159 treatments (11%). These resulted in long-term neurological sequelae in two patients (1%) with worsening from pre-treatment mRS 0–2 and mRS 4 after treatment. Complete or near-complete occlusion of the treated aneurysm according to the OKM scale was reached in 54% (85/158) at 6-month, in 68% (90/133) at 1-year, and in 83% (77/93) at 2-year follow-up, respectively. The rates of narrowing or occlusion of a vessel branch originating from the treated aneurysm according to the CSC scale were 11% (12/108) at 6-month, 20% (17/87) at 1-year, and 23% (13/57) at 2-year follow-up, respectively, with all cases being asymptomatic.

Conclusions: In this retrospective multicenter study, FRED Jr was safe and effective in the midterm occlusion of cerebral aneurysms. Most importantly, it was associated with a high rate of good clinical outcome.

Feasibility and Efficacy of Low-profile Visual Intraluminal Support Device: a Single Center Five-year Experience

INTRODUCTION

The Low-Profile Visualized Intraluminal Support (LVIS) devices are a new generation of self-expandable, high-porosity stents approved for the treatment of large to giant wide-necked intracranial aneurysms via stent-assisted coiling. Here we report the radiographic and clinical outcomes seen with LVIS, LVIS Jr. and LVIS Blue from a single institution over a five-year period.

METHODS

Patients with intracranial aneurysms treated by LVIS, LVIS Jr. and LVIS Blue technology over a five-year period (2012 - 2017) at our institution were retrospectively reviewed.

RESULTS

Seventy-four patients (55 females and 19 males; average age = 59.2) with 74 aneurysms underwent embolization of intracranial aneurysms using LVIS (N =10), LVIS Jr. (N = 47) or LVIS Blue (N =12) devices at our institution over the study period. The most common location of treated aneurysms was the anterior communicating artery (31%), followed by the basilar artery (19%), and the middle cerebral artery (13%). The mean neck and dome sizes were 3.9±1.5mm and 6.6±3.2mm, respectively. The median follow-up time was 6 months. At the last radiographic follow-up, 93.1% of patients had complete occlusion (RR-I or OKM-D). In 5 cases (7%), the LVIS stent failed to open, requiring balloon angioplasty (N=3) or stent recapture and use of a non-LVIS branded device (N=2). Five patients had post-embolization infarcts, and 1 patient had an intra-operative dome rupture.

CONCLUSION

LVIS brand of stents is a safe, effective, and technically feasible treatment strategy for wide-neck intracranial aneurysms, with high deployment success and aneurysm obliteration rates.

A novel score for evaluating cerebral aneurysms treated with flow diversion: 4F-flow diversion predictive score

Background and purpose

Although grading scales for angiography outcomes following cerebral aneurysm treatment with flow diversion have been published, physicians have not widely adopted these scales in practice. The aim of this study is to propose and validate a novel Flow diversion Predictive Score (4F-FPS) grading scale based on previously established scales that is simple and reliable.

Methods

We retrospectively analyzed consecutive patients who underwent endovascular treatment for cerebral aneurysms with flow diversion between January 2014 and September 2019. The included patients were randomly divided into the derivation and validation group in a 70/30 ratio, respectively. Aneurysms were classified as incomplete or complete occlusion based on final angiography outcomes. 4F-FPS was derived to predict aneurysm occlusion from multivariate logistic regression analyses in the derivation group and validated with previously published grading scales in the validation group.

Results

Overall, 662 patients [mean age, 53.8 years; 72.5% (480/662) female] with 662 aneurysms treated with the Pipeline^TM flow diverter were included [69.9% (463/662) derivation group, 30.1% (199/662) validation group]. The incidence of aneurysm occlusion was 82.7%. 4F-FPS demonstrated significant discrimination in 10-fold cross validation [mean receiver operating characteristic (ROC) area, 0.862 ± 0.055] and calibration (Cox & Snell R ², 0.251; Nagelkerke R ², 0.413) in the derivation group. The ROC area of 4F-FPS score in both the derivation and validation groups is the largest compared with previously published grading scales/scores (p < 0.05), which shows better sensitivity and specificity. The 4F-FPS score showed excellent prediction, discrimination, and calibration properties.

Conclusion

The 4F-FPS score is a simple and reliable tool to predict angiography outcome after flow diversion treatment. If widely adopted, it may provide a common language to be used in future reporting of flow diversion results for clinical trials and daily practice.

Clinical trial registration

http://www.clinicaltrials.gov. Unique identifier: NCT03831672.

"Trapped labelled spins"-related signal on arterial spin labelling in the assessment of flow-diverted aneurysms: preliminary experience

PURPOSE

To investigate ASL-MRI features of flow-diverted aneurysms, review their haemodynamic surrogates, and discuss their pertinent clinical implications.

METHODS

Retrospective single institutional analysis was performed on the clinical and imaging data of patients who underwent digital subtraction angiography (DSA) and ASL-MRI after endovascular flow diversion for cerebral aneurysms. Pseudo-continuous ASL-MRI was performed with post-label delays of 1525-1800 ms. Intra-aneurysmal "trapped labelled spins" (TLS)-related hypersignal, as seen on cerebral blood flow (CBF)-weighted maps of ASL-MRI, was investigated. Intermodality equivalence with DSA [O'Kelly-Marotta (OKM) grading for occlusion], 3D-TOF-MRA, and 3D spin-echo T1-weighted ("black-blood") images was assessed.

RESULTS

Ten cases were included. "TLS" signal was demonstrable in 7/8 (87.5%) of the DSA-visible flow-diverted aneurysms (OKM grade B3, n = 6; OKM grade A3, n = 2). No TLS was seen in both OKM-D (excluded) aneurysms. TLS was not visualised in an OKM-B3 aneurysm with < 3 mm opacifying remnant. 3D-TOF-MRA and ASL-MRI were discordant at 5 instances (45.4%; TOF-MRA false negative, n = 4; false positive, n = 1). Loss of flow void on black-blood images corresponded to the absence of TLS and vice versa in all cases but one.

CONCLUSION

"Trapped labelled spins"-related signal on ASL-MRI occurs in patent large aneurysms that have undergone successful endovascular flow diversion. This phenomenon likely represents an interplay of a multitude of haemodynamic factors including decelerated intra-aneurysmal inflow and outflow restriction. Serial intra-saccular TLS signal changes may hold diagnostic value, including contexts where 3D-TOF-MRA interpretation becomes dubious. "Trapped labelled spins"-related signal as a non-invasive proxy marker of aneurysm patency can possibly obviate unnecessary DSA.

Long-term clinical and angiographic follow-up results of the dual-layer flow diverter device (FRED) for the treatment of intracranial aneurysms in a multicenter study

PURPOSE

Our aim was to determine the long-term safety and efficacy of the Flow Re-Direction Endoluminal Device (FRED) in this multicenter study with prospective design.

MATERIALS-METHOD

This study included 136 consecutive patients with 155 aneurysms treated between March 2013 and June 2016 in 10 centers. Twenty-two (16.2%) patients presented with rupture of the index aneurysm. Large/giant aneurysms comprised 1/3 of the cohort. Adjuvant coil use during the treatment was 15.5%. The effectiveness measure in the study was the percentage of aneurysms with stable occlusion at follow-up.

RESULTS

Vascular imaging follow-up was performed at least once in 131/136 (96.3%) patients with 148/155 (95.5%) aneurysms up to 75 months (mean: 37.3 months; median: 36 months according to latest follow-up), and 102/155(65.8%) aneurysms in 90/136 (66.2%) patients had ≥ 24-month control. According to the latest controls, the overall stable occlusion rate was 91.9% (95% CI, 87.5 to 96.3%). Three out of 148 aneurysms with follow-up were retreated (2%, 95% CI 0.0 to 4.3%). Adverse events were noted in 19/136 (14%, 95% CI, 9 to 21%) patients with a morbidity of 1.5% (95% CI, 0.0 to 3.5%). Mortality was 1/136 (0.7%, 95% CI, 0.02 to 2.2%) and was unrelated to aneurysm treatment. In-stent stenosis (ISS) was detected in 10/131 of the patients with follow-up (7.6%, 95% CI; 3.1 to 12.2%), only one being symptomatic. No adverse events have occurred in any of the patients with follow-up after 24 months, except the one resulting from ISS.

CONCLUSION

In the treatment of cerebral aneurysms which were candidates for flow diversion technique, this study showed long-term efficacy of FRED with good safety and occlusion rates.

Long-term safety and efficacy of distal aneurysm treatment with flow diversion in the M2 segment of the middle cerebral artery and beyond

BACKGROUND

Indications for flow diversion stent (FDS) treatment are expanding. However, there is still a lack of evidence for the long-term outcome in distally located aneurysms in the M2 segment of the middle cerebral artery (MCA) and beyond.

METHODS

Consecutive subjects (from June 2013 to August 2020) with MCA aneurysms in the M2 segment or beyond treated with FDS were reviewed retrospectively. The primary endpoints for clinical safety were the absence of mortality, stroke event, re-rupture of the aneurysm, and worsening of clinical symptoms. The primary endpoint for treatment efficacy was complete/near-complete occlusion at follow-up after 12 months.

RESULTS

23 patients were identified: 7 aneurysms were located in the M2 segment of the MCA, 4 in the M2-M3 bifurcation, 2 in M3, 3 in M3-4 branching, and 2 in M4; 5 aneurysms were located in M2 with extension into the M1-M2 bifurcation. 13 aneurysms were of fusiform morphology, 8 sacculofusiform, and 2 saccular. 16 aneurysms were of highly suspected dissecting etiology. The median diameter of the parent vessel was 2.1 mm proximally and 2 mm distally. The median time of the follow-up was 30 months (range 16 months to 6 years). Complete/near complete occlusion was observed in 14/20 patients (70%) and one stable remodeling (5%) was seen at 12 months. 22 patients (95.6%) had an excellent clinical outcome (mRS 0-1) at 6 months. Technical challenges associated with the deployment of FDS occurred in 8.7% of cases. Severe complications, intraparenchymal hemorrhage and re-rupture of the aneurysm occurred in 2 patients (8.7%).

CONCLUSION

Flow diversion of distally located aneurysms is technically feasible with low morbidity and mortality.

p64 flow diverter: Results in 108 patients from a single center

BACKGROUND AND PURPOSE

Flow diverters are increasingly used to treat intracranial aneurysms. We report the safety and efficacy of the p64 flow diverter, a resheathable and detachable device for intracranial aneurysms.

MATERIALS AND METHODS

We retrospectively reviewed 108 patients with 109 aneurysms treated with the p64 between March 2014 and July 2019. There were 87 women and 21 men, mean age 57 years. Of 109 aneurysms, 74 were discovered incidentally, 12 were symptomatic, 18 were previously treated, and five were ruptured dissection aneurysms. A total of 10 aneurysms were located in the posterior circulation. The mean aneurysm or remnant size was 8.1 mm.

RESULTS

Hemorrhage by perforation with the distal guidewire occurred in two patients with permanent neurological deficits in one. In one patient, acute in-stent occlusion caused infarction with a permanent deficit. Permanent morbidity was 1.9% (2 of 108, 95%CI 0.1-6.9%); there was no mortality. During follow-up, three in-stent occlusions occurred, all asymptomatic. There were no delayed hemorrhagic complications. At six months, 77 of 96 aneurysms (80.2%) were completely occluded, and at last follow-up, this increased to 93 of 96 aneurysms (96.9%). In-stent stenosis at any degree occurred in 11 patients, progressing to asymptomatic complete occlusion in one. In the other patients, stenosis resolved or improved at further follow-up.

CONCLUSION

The p64 offers an effective and safe treatment option. Aneurysm occlusion rate was 97% at last follow-up, mostly achieved with a single device. There were no delayed hemorrhagic complications. Delayed in-stent stenosis infrequently progresses to occlusion but remains a matter of concern.

Is Contrast Stasis After Pipeline Embolization Device Deployment Associated with Higher Aneurysm Occlusion Rates?

OBJECTIVE

To assess the association of degree of contrast stasis in intracranial aneurysms (IAs) immediately after Pipeline embolization device (PED; Medtronic, Dublin, Ireland) deployment with 6- and 12-month angiographic occlusion rates.

METHODS

This retrospective cohort study included consecutive patients undergoing PED deployment for saccular IA treatment at a large-volume cerebrovascular center over a 4-year 9-month period. Angiographic images obtained immediately after PED deployment were graded according to amount of intra-aneurysmal contrast flow during the late venous phase: 0 = no stasis; 1 = <50% contrast stasis; 2 = 50%-75% stasis; and 3 = >75%-99% stasis. Follow-up occlusion rates were determined by digital subtraction angiography, computed tomographic angiography, or magnetic resonance angiography.

RESULTS

The study included 119 patients in whom 182 PEDs were deployed to treat 141 aneurysms. A single PED was deployed in 105 (74.5%) aneurysms. The internal carotid artery was the commonest aneurysm site (119 [85%]). Fifty-two (36.9%) aneurysms were grade 0; 33 (23.4%) were grade 1; 46 (32.6%) were grade 2; and 10 (7.1%) were grade 3 immediately post-treatment. A 6-month follow-up angiogram available for 101 aneurysms showed complete occlusion (no flow into the aneurysm) in 74 (73.3%) aneurysms. A 12-month follow-up study available for 132 aneurysms showed complete occlusion in 79.5%. At last follow-up, occlusion rates were not significantly different for different contrast stasis grades (P = 0.60). Mean angiographic follow up for all IAs was 23v±v17.7 months. IA size, sex, age, and smoking were not significant predictors of occlusion.

CONCLUSIONS

The degree of aneurysm contrast stasis immediately after PED deployment is not statistically associated with 6- and 12-month angiographic occlusion rates.

Preliminary Experience with Cangrelor for Endovascular Treatment of Challenging Intracranial Aneurysms

BACKGROUND AND PURPOSE

Cangrelor is a P2Y12 inhibitor that presents the advantage of having a short half-life. Its use may be helpful in the management of antiplatelet therapy for patients with intracranial aneurysms treated by stent-assisted coiling or flow-diverter stents. The purpose of this study was to report early experiences in using cangrelor for such indications.

MATERIAL AND METHODS

From October 2017 to November 2018, 7 consecutive patients (5 females, 2 males, mean age = 56 years) were managed with cangrelor as antiplatelet therapy, combined with aspirin, for stent-assisted coiling embolization and flow-diverter embolization of challenging intracranial aneurysms. Anti-aggregation protocols, including cangrelor, were systematically recorded. Treatment-related complications (minor/major hemorrhagic complications, ischemic complications) as well as clinical and angiographic outcomes (evaluated at 8.7 ± 4.2 and 8.75 ± 10 months, respectively) were retrospectively analyzed.

RESULTS

Of the aneurysms 71.4% (5 out of 7) were ruptured and treated in the acute phase. In one case cangrelor was used as an alternative to clopidogrel in an asymptomatic hemorrhagic complication after stent-assisted coiling for better control of a possible worsening of the intracranial bleeding. Of the patients, 1 (14%) with a complex ruptured MCA aneurysm treated with a flow-diverter stent experienced a severe intracranial hemorrhage, which occurred after switching the cangrelor to ticagrelor and eventually led to death. No hemorrhagic complications under cangrelor were recorded for the six remaining patients. No mRS worsening was observed at discharge, except for the patient who died and six out of the seven patients had a mRS ≤2 at follow-up.

CONCLUSION

Cangrelor is a new antiplatelet therapy with a P2Y12 inhibiting effect, with a rapid onset and offset of action, owing to its short half-life. This cases series presents a pilot experience with promising results in terms of antiplatelet management for challenging intracranial aneurysms treated by stent assisted coiling or flow-diverter stents.

Stent-Assisted Coil Embolization of MCA Bifurcation Aneurysms at a Hypoplastic M1 Branch by Use of Hook Technique

BACKGROUND

We describe the Hook technique enabling coil embolization in unfavorable M1 bifurcation aneurysms and analyze the morphologic variations in M1 bifurcation to evaluate how often such aneurysms can be seen.

METHODS

Among 42 MCA aneurysms treated by stent-assisted coil embolization, aneurysms arising at the acute-angled hypoplastic M1 branch (n = 14) were treated by the Hook technique, in which a short stent was deployed only to protect the aneurysm neck after microcatheter selection of the hypoplastic M2, followed by subsequent coiling of the aneurysm. Outcome was evaluated, including Raymond classification, coil packing density, final modified Rankin Scale (mRS), and recurrence. Separately, 100 middle cerebral artery (MCA) bifurcation aneurysms were analyzed to assess the proportion of such unfavorable aneurysms.

RESULTS

Procedural success of the Hook technique was obtained in 13 of 14 patients (93%). A mean packing density of 30% was achieved. Magnetic resonance angiographic follow-up at a median 4 months (range, 1-26 months) showed complete occlusion in 11 patients and residual neck filling in 3 patients. There was no clinical event (mRS = 0) over a median 17 months (range, 2-26 months) of clinical follow-up. One patient had a thrombotic occlusion during the procedure, which was resolved after tirofiban infusion, without evidence of an infarct or deficit. Of the 100 MCA bifurcation aneurysms, aneurysm arising in asymmetric hypoplastic M2 division was the most common type (48%).

CONCLUSIONS

The Hook technique enabled stent-assisted coiling of M1 bifurcation aneurysm with extension along the asymmetric hypoplastic M2 division and also securing the M2 branch.

Flow diversion treatment of complex bifurcation aneurysms beyond the circle of Willis: complications, aneurysm sac occlusion, reabsorption, recurrence, and jailed branch modification at follow-up

OBJECTIVE

The purpose of this study is to present the authors' medium-term results, with special emphasis on complications, occlusion rate of the aneurysm sac (digital subtraction angiography [DSA] and MRI), and the fate of cortical branches and perforating arteries covered ("jailed") by the flow diverter (FD) stent.

METHODS

Between January 2010 and September 2017, 29 patients (14 female) with 30 aneurysms were treated with an FD stent. Twenty-one aneurysms were at the middle cerebral artery bifurcation, 8 were in the anterior communicating artery region, and 1 was a pericallosal artery bifurcation. Thirty-five cortical branches were covered. A single FD stent was used in all patients. Symptomatic and asymptomatic periprocedural and delayed complications were reported. DSA and MRI controls were analyzed to evaluate modification of the aneurysm sac and jailed branches.

RESULTS

Permanent morbidity was 3.4% (1/29), due to a jailed branch occlusion, with a modified Rankin Scale (mRS) score of 2 at the last follow-up. Mortality and permanent complication with poor prognosis (mRS score > 2) rates were 0%. The mean follow-up time for DSA and MRI (mean ± SD) was 21 ± 14.5 months (range 3-66 months) and 19 ± 16 months (range 3-41 months), respectively. The mean time to aneurysm sac occlusion (available for 24 patients), including stable remodeling, was 11.8 ± 6 months (median 13, range 3-27 months). The overall occlusion rate was 82.1% (23/28), and it was 91.7% (22/24) in the group of patients with at least 2 DSA control sequences. One recanalization occurred at 41 months posttreatment. At the time of publication, at the latest follow-up, 7 (20%) of 35 covered branches were occluded, 18 (51.4%) showed a decreased caliber, and the remaining 10 (28.5%) were unchanged. MRI T2-weighted sequences showed complete sac reabsorption in 7/29 aneurysms (24.1%), and the remaining lesions were either smaller (55.2%) or unchanged (17.2%). MRI revealed asymptomatic and symptomatic ischemic events in perforator territories in 7/28 (25%) and 4/28 (14.3%) patients, respectively, which were reversible within 24 hours.

CONCLUSIONS

Flow diversion of bifurcation aneurysms is feasible, with low rates of permanent morbidity and mortality and high occlusion rates; however, recurrence may occur. Caliber reduction and asymptomatic occlusion of covered cortical branches as well as silent perforator stroke are common. Ischemic complications may occur with no identified predictable factors. MRI controls should be required in all patients to evaluate silent ischemic lesions and aneurysm sac reabsorption over time.

Endovascular Treatment of Wide Neck Aneurysms

BACKGROUND

An aneurysm is an abnormal focal dilatation of an artery. Most of the unruptured aneurysms are asymptomatic and discovered incidentally or some of them symptomatic with mass effect or nerve palsy, but rupture of aneurysm results in a potentially life-threatening subarachnoid haemorrhage. Aneurysms with wide necks are defined by neck diameters greater than 4 mm or dome-to-neck ratios less than 2 and are the most difficult to treat with the endovascular method.

AIM

This study aimed to analyse the endovascular treatment of intracranial aneurysms with a wide neck.

METHODS

The study population included 37 patients with 46 aneurysms referred to the University Clinic of Radiology in Skopje, the Republic of Macedonia for endovascular treatment during the period January 2013 to May 2018. This study included 24 females and 13 males, ranging in age from 25 to 74 years.

RESULTS

From total 46 treated aneurysms 13 were ruptured and 33 unruptured. Six patients were with multiple aneurysms. In these study complex aneurysms were treated with combined technique, 5 with balloon-assisted coiling, 25 with stent-assisted coiling, 6 stents, 2 with flow diverter assisted coiling, 6 FD and 2 with partial coil filling without assistance device.

CONCLUSION

Aneurysms with wide neck remain a challenge for endovascular treatment. But the development of new techniques and materials in the treatment of aneurysms makes endovascular treatment of intracranial aneurysms safe and feasible.

Low-profile Visualized Intraluminal Support Junior Device for the Treatment of Intracranial Aneurysms

Objective: Early case series suggest that the recently introduced Low-profile Visualized Intraluminal Support Junior (LVIS Jr.) device (MicroVention-Terumo, Inc., Tustin, CA) may be used to treat wide-necked aneurysms that would otherwise require treatment with intrasaccular devices or open surgery. We report our single-center experience utilizing LVIS Jr. to treat intracranial aneurysms involving 1.8-2.5 mm parent arteries.

Methods: We retrospectively reviewed records of patients treated with the LVIS Jr. device for intracranial aneurysms at a single center. A total of 21 aneurysms were treated in 18 patients. Aneurysms were 2-25 mm in diameter; one was ruptured, while three had recurred after previous rupture and treatment. Lesions were distributed across the anterior (n=12) and posterior (n=9) circulations. Three were fusiform morphology.

Results: Stent deployment was successful in 100% of cases with no immediate complications. Seventeen aneurysms were treated with stent-assisted coil embolization resulting in immediate complete occlusion in 94% of cases. Two fusiform aneurysms arising from the posterior circulation were further treated with elective clip ligation after delayed expansion and recurrence; no lesions required further endovascular treatment. Four aneurysms were treated by flow diversion with stand-alone LVIS Jr. stent, and complete occlusion was achieved in three cases. Small foci of delayed ischemic injury were noted in two patients in the setting of antiplatelet medication noncompliance. No in-stent stenosis, migration, hemorrhage, or permanent deficits were observed. Good functional outcome based on the modified Rankin Scale score (mRS ≤ 2) was achieved in 100% of cases.

Conclusion: Our midterm results suggest that the LVIS Jr. stent may be used for a variety of intracranial aneurysms involving small parent arteries (1.8-2.5 mm) with complete angiographic occlusion, parent vessel preservation, and functional clinical outcomes. This off-label expansion would increase the number of aneurysms amenable to endovascular treatment. Future studies may build upon our experiences with flow diversion and treatment of complex or multiple lesions.

Middle Cerebral Artery Bifurcation Aneurysms Treated by Extrasaccular Flow Diverters: Midterm Angiographic Evolution and Clinical Outcome

BACKGROUND AND PURPOSE

Flow diverters have been increasingly used lately in off-label, distal intracranial aneurysm treatments. Our aim was to evaluate the effectiveness of flow diverters in the treatment of middle cerebral artery bifurcation aneurysms and to analyze midterm angiographic patterns of regional flow modifications for safety and clinical outcomes.

MATERIALS AND METHODS

Consecutive patients treated from January 2010 to December 2014 by the authors by using endovascular flow-diverting stents for MCA bifurcation aneurysms were evaluated retrospectively with prospectively maintained data. All patients had been followed for at least 12 months after treatment, with at least 2 control angiograms; regional flow-related angiographic modifications were registered by using a new angiographic outcome scale for flow diverters. Data were analyzed with emphasis on procedure-related events, angiographic results, and clinical outcome.

RESULTS

Fifty-eight patients were included in the study, with 63 MCA bifurcation aneurysms; 13 of these were large and giant. Pretreatment mRS was 0 for 12 patients (20.7%), 1 for 41 (70.7%), and 2 for 5 patients (8.6%). Six-month control revealed mRS 0-2 for 57 (98.3%) patients and 3 for 1 (1.7%) patient. Procedure-related morbidity and mortality were 8.6% (5/58) and 0%, respectively. From 95% of still circulating immediate postprocedure angiographic outcomes, 68% progressed to aneurysm occlusion at 6 months and 95%, to occlusion at 12 months, with a 0% aneurysm rupture rate.

CONCLUSIONS

Flow diverters seem to be an effective treatment alternative for complex MCA bifurcation aneurysms, with reasonable complication rates. Longer angiographic follow-ups are needed to assess the morphologic outcome; immediate subtotal occlusions do not seem to be related to rupture.