Stent-assisted coiling of unruptured intracranial aneurysms: long-term follow-up in 164 patients with 183 aneurysms

Balloon-Assisted Stent Visualization: A Simple Technique for Precise Measurement of Previously Placed Stent Diameter

Stent-assisted coil embolization is effective for treating intracranial aneurysms, improving outcomes and reducing recurrence rates. However, accurately measuring the diameter of a previously placed stent during imaging can be challenging due to coil artifacts. This poses difficulties in determining the coil packing and size of additional stents needed during retreatment. In a reported case, the use of a balloon enabled precise assessment of stent deployment. A 50-year-old male with a history of basilar artery-left superior cerebellar artery aneurysm underwent coil embolization, direct clipping, and stent-assisted coil embolization (SAC) over a span of 14 years. However, the aneurysm showed reenlargement over time. To address the recurrence, a balloon was used to assess the previously placed Neuroform Atlas stent. Additional coils were inserted outside the stent, and a Low-profile Visualized Intraluminal Support Blue stent was added. Postoperatively, there were no new neurological issues, and a follow-up magnetic resonance imaging showed no ischemic lesions . Balloon-assisted stent visualization (BASV) may be a useful method in the retreatment of SAC. It has the potential to provide valuable information for treatment planning.

Intracranial aneurysms treated with stent-assisted coil embolization: evaluation with four-dimensional ultrashort-TE MR angiography

OBJECTIVES

As a novel follow-up method for intracranial aneurysms treated with stent-assisted coil embolization (SACE), we developed four-dimensional magnetic resonance angiography (MRA) with minimized acoustic noise utilizing ultrashort-echo time (4D mUTE-MRA). We aimed to assess whether 4D mUTE-MRA is useful for the evaluation of intracranial aneurysms treated with SACE.

METHODS

This study included 31 consecutive patients with intracranial aneurysm treated with SACE who underwent 4D mUTE-MRA at 3 T and digital subtraction angiography (DSA). For 4D mUTE-MRA, five dynamic MRA images with a spatial resolution of 0.5 × 0.5 × 0.5 mm3 were obtained every 200 ms. Two readers independently reviewed the 4D mUTE-MRA images to evaluate the aneurysm occlusion status (total occlusion, residual neck, and residual aneurysm) and the flow in the stent using a 4-point scale (from 1 [not visible] to 4 [excellent]). The interobserver and intermodality agreement was assessed using κ statistics.

RESULTS

On DSA images, 10 aneurysms were classified as total occlusion, 14 as residual neck, and 7 as residual aneurysm. In terms of aneurysm occlusion status, the intermodality and interobserver agreement was excellent (κ = 0.92 and κ = 0.96, respectively). For the flow in the stents on 4D mUTE-MRA, the mean score was significantly higher for single stents than multiple stents (p < .001) and for open-cell type stents than closed-cell type (p < .01).

CONCLUSIONS

4D mUTE-MRA is a useful tool with a high spatial and temporal resolution for the evaluation of intracranial aneurysms treated with SACE.

KEY POINTS

• In the evaluation of intracranial aneurysms treated with SACE on 4D mUTE-MRA and DSA, the intermodality and interobserver agreement in aneurysm occlusion status was excellent. • 4D mUTE-MRA shows good to excellent visualization of flow in the stents, especially for cases treated with a single or open-cell stent. • 4D mUTE-MRA can provide hemodynamic information related to embolized aneurysms and the distal arteries to stented parent arteries.

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.

Comparison of staged-stent and stent-assisted coiling technique for ruptured saccular wide-necked intracranial aneurysms: Safety and efficacy based on a propensity score-matched cohort study

Background

Application of stent-assisted coiling and FD in acute phase of ruptured wide-necked aneurysms is relatively contraindicated due to the potential risk of ischemic and hemorrhagic complications. Scheduled stenting after initial coiling has emerged as an alternative paradigm for ruptured wide-necked aneurysms. The objective of this study is to evaluate the safety and efficacy of a strategy of staged stent-assisted coiling in acutely ruptured saccular wide-necked intracranial aneurysms compared with conventional early stent-assisted coiling strategy via propensity score matching in a high-volume center.

Methods

A retrospective review of patients with acutely ruptured saccular wide-necked intracranial aneurysms who underwent staged stent-assisted coiling or conventional stent-assisted coiling from November 2014 to November 2019 was performed. Perioperative procedure-related complications and clinical and angiographic follow-up outcomes were compared.

Results

A total of 69 patients with staged stent-assisted coiling and 138 patients with conventional stent-assisted coiling were enrolled after 1:2 propensity score matching. The median interval time between previous coiling and later stenting was 4.0 weeks (range 3.5-7.5 weeks). No rebleeding occurred during the intervals. The rate of immediate complete occlusion was lower with initial coiling before scheduled stenting than with conventional stent-assisted coiling (21.7 vs. 60.9%), whereas comparable results were observed at follow-up (82.5 vs. 72.9%; p = 0.357). The clinical follow-up outcomes, overall procedure-related complications and procedure-related mortality between the two groups demonstrated no significant differences (P = 0.232, P = 0.089, P = 0.537, respectively). Multivariate analysis showed that modified Fisher grades (OR = 2.120, P = 0.041) were independent predictors for overall procedure-related complications and no significant predictors for hemorrhagic and ischemic complications.

Conclusions

Staged stent-assisted coiling is a safe and effective treatment strategy for acutely ruptured saccular wide-necked intracranial aneurysms, with comparable complete occlusion rates, recurrence rates at follow-up and overall procedure-related complication rates compared with conventional stent-assisted coiling strategy. Staged stent-assisted coiling could be an alternative treatment option for selected ruptured intracranial aneurysms in the future.

Effects of stent-assisted coiling in comparison with flow diversion on intracranial aneurysms

Objective

The aim of this study was to investigate the efficacy and complications of stent-assisted coiling in comparison with flow diversion for wide-necked intracranial aneurysms.

Methods

Patients with wide-necked intracranial aneurysms who were treated with stent-assisted coiling or flow diversion were respectively, enrolled into the stent-assisted coiling or flow diversion treatment group. The clinical and angiographic data were analyzed.

Results

A total of 61 patients with intracranial aneurysms underwent stent-assisted coiling, including 35 (57.4%) female and 26 (42.6%) male patients with 21 (34.4%) ruptured and 40 (65.6%) unruptured aneurysms. Also, 53 patients underwent deployment of flow-diverting devices, including 30 (56.6%) female and 23 (43.4%) male patients with 25 (47.2%) ruptured and 28 (52.8%) unruptured aneurysms. Stent-assisted coiling was performed successfully in 60 patients with 63 stents deployed, and immediate aneurysm occlusion was complete occlusion in 38 (62.3%) aneurysms, residual neck in 12 (19.7%), and residual aneurysm in 10 (16.4%). Procedure-related complications included in-stent thrombosis in three (4.9%) patients, coil protrusion in three (4.9%), and re-rupture of one (1.6%) aneurysm, with a total complication rate of 11.5%. In the flow diversion group, a pipeline embolization device alone was deployed in each of the 24 (45.3%) patients, adjunctive coiling combined with a pipeline device in 29 (54.7%), and double pipeline devices in each of the 6 (11.3%) patients. Immediately after treatment, complete occlusion was achieved in 3 (5.7%) patients with adjunctive coiling, residual neck in 3 (5.7%), and residual aneurysm in 47 (88.7%). Procedure-related complications included aneurysm rebleeding in one patient (1.9%). Clinical and angiographic follow-up was performed 13–49 months (median 29) after the procedure for 49 (80.3%) patients with stent-assisted coiling, with complete aneurysm occlusion in 27 (55.1%) aneurysms, residual neck in 3 (6.1%), residual aneurysm in 5 (10.2%), and recurrence in 14 (28.6%). Follow-up was performed for 14–37 (median 25) months in 45 (84.9%) patients with flow diversion treatment, with complete occlusion in 39 (86.7%) patients, residual neck in 5 (11.1%), residual aneurysm in 1 (2.2%), and no aneurysm recurrence.

Conclusions

Stent-assisted coiling comes with more complications but fewer permanent aneurysm occlusions than flow diverters, and flow diverters are superior to stent-assisted coiling in the treatment of wide-necked intracranial aneurysms, especially in the long-term effect.

Characteristics of Unruptured Intracranial Aneurysms with Delayed Rupture Following Coil Embolization: Case Series and Review of the Literature

Objective

Long-term clinical outcomes including delayed rupture of unruptured intracranial aneurysms (UIAs) after coil embolization (CE) remain unclear. The purpose of this study was to evaluate the precise timing of re-treatment for recanalized UIAs before rupture.

Methods

From February 2012 to June 2020, a total of 197 patients with 207 UIAs underwent CE in our institution and were followed up for more than 6 months. The follow-up period, as well as morphological changes from treatment to recanalization, regrowth, and rupture, was retrospectively analyzed. Delayed rupture was defined as a rupture that occurred more than 1 month after CE.

Results

The average length of follow-up was 48.7 months. Three of 207 UIAs (1.45%) ruptured after CE. The aneurysm locations were the middle cerebral artery (MCA), anterior communicating artery (AcomA), and internal carotid artery-posterior communicating artery (ICA-Pcomm). The annual rupture rate after CE was 0.36%. Immediately after the first CE, treated aneurysms were graded according to the Modified Raymond-Roy Classification with class II for MCA aneurysms and class IIIb for AcomA and ICA-Pcomm aneurysms. The ICA-Pcomm aneurysm was treated with two additional CEs and was finally graded as class I. In all cases, DSA or MRA before aneurysm rupture showed recanalization and regrowth of aneurysms. The average periods from final embolization to regrowth and from regrowth to rupture were 54.3 months (±16.8) and 2.3 months (±0.9), respectively.

Conclusion

UIAs with recanalization and regrowth after CE should undergo re-treatment as early as possible.

Usefulness of Silent MRA for Evaluation of Aneurysm after Stent-Assisted Coil Embolization

OBJECTIVE

To determine the usefulness of Silent MR angiography (MRA) for evaluating intracranial aneurysms treated with stent-assisted coil embolization.

MATERIALS AND METHODS

Ninety-nine patients (101 aneurysms) treated with stent-assisted coil embolization (Neuroform atlas, 71 cases; Enterprise, 17; LVIS Jr, 9; and Solitaire AB, 4 cases) underwent time-of-flight (TOF) MRA and Silent MRA in the same session using a 3T MRI system within 24 hours of embolization. Two radiologists independently interpreted both MRA images retrospectively and rated the image quality using a 5-point Likert scale. The image quality and diagnostic accuracy of the two modalities in the detection of aneurysm occlusion were further compared based on the stent design and the site of aneurysm.

RESULTS

The average image quality scores of the Silent MRA and TOF MRA were 4.38 ± 0.83 and 2.78 ± 1.04, respectively (p < 0.001), with an almost perfect interobserver agreement. Silent MRA had a significantly higher image quality score than TOF MRA at the distal internal carotid artery (n = 57, 4.25 ± 0.91 vs. 3.05 ± 1.16, p < 0.001), middle cerebral artery (n = 21, 4.57 ± 0.75 vs. 2.19 ± 0.68, p < 0.001), anterior cerebral artery (n = 13, 4.54 ± 0.66 vs. 2.46 ± 0.66, p < 0.001), and posterior circulation artery (n = 10, 4.50 ± 0.71 vs. 2.90 ± 0.74, p = 0.013). Silent MRA had superior image quality score to TOF MRA in the stented arteries when using Neuroform atlas (4.66 ± 0.53 vs. 3.21 ± 0.84, p < 0.001), Enterprise (3.29 ± 1.59 vs. 1.59 ± 0.51, p = 0.003), LVIS Jr (4.33 ± 1.89 vs. 1.89 ± 0.78, p = 0.033), and Solitaire AB stents (4.00 ± 2.25 vs. 2.25 ± 0.96, p = 0.356). The interpretation of the status of aneurysm occlusion exhibited significantly higher sensitivity with Silent MRA than with TOF MRA when using the Neuroform Atlas stent (96.4% vs. 14.3%, respectively, p < 0.001) and LVIS Jr stent (100% vs. 20%, respectively, p = 0.046).

CONCLUSION

Silent MRA can be useful to evaluate aneurysms treated with stent-assisted coil embolization, regardless of the aneurysm location and type of stent used.

Validity of PETRA-MRA for Stent-Assisted Coil Embolization of Intracranial Aneurysms

Objective

Pointwise encoding time reduction with radial acquisition (PETRA) using magnetic resonance angiography (MRA) is a non-enhanced MRA technique employing an ultrashort echo time, and is known to significantly reduce the magnetic susceptibility of coils and stents during post-embolization imaging. We evaluated the quality of PETRA-MRA images for use at the follow-up assessment of stent-assisted coil embolization procedures performed to treat aneurysms.

Methods

A total of six aneurysm patients who were treated by stent-assisted coil embolization were included. All patients underwent PETRA-MRA, time-of-flight (TOF)-MRA performed with MAGNETOM Skyra (Siemens), and digital subtraction angiography (DSA) performed with Infinix Celeve-i INFX-8000V (Canon Medical Systems) and Allura Clarity FD20/15 (Philips). The PETRA-MRA images were compared with those from DSA and TOF-MRA to validate the aneurysm occlusion status and visually assess the blood flow within the stent. Four independent specialists graded occlusion status and flow visualization through the stent using a four-point scale, where 4 points represented excellent visualization of flow within the stent.

Results

The aneurysm was located in the internal carotid artery in two patients, the middle cerebral artery in two patients, the top of the basilar artery in one patient, and the vertebral artery-posterior inferior cerebellar artery (VA-PICA) in one patient. Three patients were treated using a Neuroform Atlas Stent system, one using an Enterprise2 VRD, one using two Neuroform Atlas stents for Y-stenting, and the remaining patient using a Neuroform Atlas and an Enterprise2 VRD for Y-stenting. With DSA, the postoperative aneurysm occlusion status was neck remnant (NR) in five cases and complete obliteration (CO) in one case. DSA and PETRA-MRA evaluations demonstrated an equal occlusion status in five of six cases, whereas DSA and TOF-MRA were equal in two of six cases. The mean visualization score for PETRA-MRA was 3.33 ± 0.82, whereas that for TOF-MRA was 2.17 ± 1.33. On the PETRA-MRA images, blood flow through the stent was well-visualized and produced an aneurysm occlusion status score comparable to DSA, especially in the three cases using the Neuroform Atlas Stent System where the visualization was scored 4 points. In the case of the VA-PICA aneurysm, for which an Enterprise2 VRD was used, PETRA-MRA images were insufficient for postoperative assessment.

Conclusion

PETRA-MRA can provide good visualization of the blood flow within a stent and displays a clear blood signal near the coils, barring small magnetic susceptibility artifacts. Therefore, PETRA-MRA may be an effective option for follow-up imaging after stent-assisted coil embolization.

Stent-Assisted Coiling of Unruptured Intracranial Aneurysms with Wide Neck

Objective:

Morbidity and mortality in patients experiencing the rupture of intracranial aneurysm ruptures are high. We conducted a systematic review and meta-analysis to investigate the role of stent-assisted coiling (SAC) for unruptured intracranial aneurysms (UIAs) with wide neck.

Materials and Methods:

The current meta-analysis was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Pooled proportions with 95% confidence intervals (CIs) of ten outcomes of interest were calculated.

Results:

We finally reviewed 13 studies, including 976 patients. The technical success of the method was 98.43% (95% CI: 95.62–99.95). Early outcomes included total periprocedural obliteration with a rate of 50.20% (95% CI: 36.09–64.30) and periprocedural rupture with zero rate. During the follow-up period, ranging from 6 months to 2 years, the total postprocedural obliteration rate was 63.83% (95% CI: 45.80–80.18) and the overall late rupture rate was 0.41% (95% CI: 0.00–2.38). The pooled in-stent stenosis rate was calculated at 1.24% (95% CI: 0.02–3.63). We also estimated a pooled rate of 0.02% (95% CI: 0.00–0.51) and 4.33% (95% CI: 2.03–7.23) for total mortality and overall neurological complications, respectively. A pooled rate of 3.94% (95% CI: 1.48–7.33) was found for stroke. Finally, the recanalization rate was recorded at 7.07% (95% CI: 4.35–10.26).

Conclusions:

SAC of UIAs with wide neck seems to be a safe and acceptable alternative to surgical clipping. Although early results concerning total periprocedural obliteration may be modest, follow-up outcomes may be indicative of adequate occlusion of treated UIAs.

Long-Term Rupture Risk in Patients with Unruptured Intracranial Aneurysms Treated with Endovascular Therapy: A Systematic Review and Meta-Analysis

BACKGROUND

Surveillance imaging of previously unruptured, coiled aneurysms remains routine even though reports of rupture of these aneurysms are extremely rare.

PURPOSE

We performed meta-analysis to examine long-term rupture risk over ≥1-year follow-up duration in patients with unruptured intracranial aneurysm who underwent endovascular therapy.

DATA SOURCES

Multiple databases were searched for relevant publications between 1995 and 2018.

STUDY SELECTION

Studies reporting outcome of long-term rupture risk over ≥1-year follow-up in treated patients with unruptured intracranial aneurysms were included.

DATA ANALYSIS

Random effects meta-analysis was used, and results were expressed as long-term rupture rate per 100 patient-year with respective 95% CIs. For ruptured aneurysms during follow-up, data were collected on size and completeness of initial Treatment.

DATA SYNTHESIS

Twenty-four studies were identified. Among 4842 patients with a mean follow-up duration of 3.2 years, a total of 12 patients (0.25%) experienced rupture of previous unruptured intracranial aneurysms after endovascular treatment. Nine of these 12 patients harbored aneurysms that were large, incompletely treated, or both. A total of 2 anterior circulation, small, completely coiled aneurysms subsequently ruptured. The long-term rupture rate per 100 patient-year for unruptured intracranial aneurysms treated with endovascular therapy was 0.48 (95% CI, 0.45-0.51). Retreatment was carried out in 236 (4.9%) of these 4842 patients.

LIMITATIONS

A limitation of the study is that a lack of systematic nature of follow-up and mean follow-up duration of 3.2 years are not sufficient to make general recommendations about aneurysm followup paradigms.

CONCLUSIONS

Given a 5% retreatment rate, postcoil embolization spontaneous rupture of previously unruptured, small- and medium-sized, well-treated aneurysms is exceedingly rare.

Application of zero echo time MR angiography in follow-up of intracranial aneurysm remnant and in-stent lumen after embolization: a comparison study with digital subtraction angiography

Background

Intracranial aneurysm with endovascular treatment needs to be followed-up with a proper imaging method.

Purpose

To evaluate the performance of magnetic resonance angiography (MRA) with zero echo time at 1.5-T in assessing the intracranial aneurysm remnant and in-stent lumen as compared with time-of-flight MRA, with digital subtraction angiography as the gold standard.

Material and Methods

A total of 46 patients (17 men; mean age = 56.6±13.7 years) with 54 aneurysms who underwent coil embolization with or without stent were enrolled in this study. The presence of aneurysm remnant and the visualization of in-stent lumen were evaluated. The agreement of remnant identification between MRA with zero echo time and time-of-flight MRA with digital subtraction angiography was evaluated using Cohen’s kappa analysis. The performance of in-stent lumen visualization between MRA with zero echo time and time-of-flight MR angiography was compared with Chi-square test.

Results

Of 54 aneurysms, 27 were found to have remnants by digital subtraction angiography. The kappa value in identification of remnant of aneurysm was 0.852 between MRA with zero echo time and digital subtraction angiography and 0.741 between time-of-flight MRA and digital subtraction angiography. In detecting remnant of aneurysm, the sensitivity, specificity, positive predictive value, and negative predictive value were 96.3%, 88.9%, 89.7%, and 96.0% for MRA with zero echo time and 91.7%, 83.3%, 81.5%, and 92.6% for time-of-flight MRA, respectively. In visualizing in-stent lumen, MRA with zero echo time had better performance than time-of-flight MRA ( P < 0.001).

Conclusion

MR angiography with zero echo time might be a better non-invasive approach in assessing remnant of aneurysms and in-stent lumen as compared with time-of-flight MRA.

Evaluation of clinical and anatomical outcome of staged stenting after acute coiling of ruptured intracranial aneurysms

INTRODUCTION

Stent-assisted coiling has widened indications and improved stability of endovascular treatment of intracranial aneurysms. However, stent-assisted coiling is usually not used to treat acutely ruptured intracranial aneurysms to avoid antiplatelet therapy. The objective of this study is to evaluate a strategy of staged endovascular treatment of ruptured intracranial aneurysms including coiling at the acute phase with complementary stenting with or without coiling at the subacute phase.

MATERIAL AND METHODS

Between 2012 and 2017, we retrospectively identified, in our prospectively maintained database, all patients treated for a ruptured intracranial aneurysm based on this staged stenting strategy. Clinical charts and imaging follow-up were analyzed to assess the procedural safety and feasibility as well as clinical and anatomical outcome.

RESULTS

We identified 23 patients with 23 intracranial aneurysms including 15 (65.2%) women with a mean age of 50 years (range 24-69 years). No rebleeding occurred during the mean delay of 24.3 days between initial coiling and stenting. All procedures were successful and additional coiling was performed in 5/23 procedures (21.7%). Clinical status was unchanged in all patients. At follow-up, the modified Rankin scale was graded 0 in 19/23 (82.6%), 1 in 2/23 (8.7%), and 2 in 2/23 (8.7%) patients, respectively. The rate of complete occlusion rose from 30.4% before the stenting procedure to 52.2% immediately after and 72.7% at follow-up.

CONCLUSION

This strategy of early staged stenting in selected patients is safe and improves immediate intracranial aneurysm occlusion and long-term stability in this population at high risk of intracranial aneurysm recurrence with coiling alone.

Cerebral aneurysm neck diameter is an independent predictor of progressive occlusion after stent-assisted coiling

BACKGROUND

Some intracranial aneurysms treated by stent-assisted coiling (SAC) with incomplete occlusion undergo progressive occlusion (PO) during follow-up period. We analyzed the predictors for the occurrence of PO.

METHODS

Among 74 cerebral aneurysms treated by SAC using the Enterprise or Neuroform stents from 2010 to 2015, we included 43 aneurysms with occlusion grade of neck remnant (NR, n = 36) or residual aneurysm (RA, n = 7) at the post-procedure. We defined PO as improvement in occlusion grade from RA to NR, or from NR or RA to complete occlusion on angiographic follow-up imaging at 6 months after the procedure. We analyzed the independent predictors for PO using a multivariate logistic regression model and receiver operating characteristic (ROC) curve analysis.

RESULTS

Forty-three aneurysms were analyzed, with mean volume embolization ratio of 30.3 ± 6.7%. Twenty aneurysms (47%) achieved PO. Univariate analysis found that the median neck diameter of the aneurysms was smaller in aneurysms with PO than others. Multivariate logistic regression analysis also found that the odds ratio of neck diameter of the aneurysm for PO was 0.44 (95% CI, 0.19-0.82, p < 0.01). Moreover, ROC curve analysis for PO found that the optimal cut-off value of the neck diameter was 5.5 mm, with a sensitivity of 95%, specificity of 57% (p < 0.01).

CONCLUSIONS

Incompletely occluded aneurysms with a neck diameter of 5.5 mm or less might be more likely to develop PO within 6 months after SAC by using Enterprise or Neuroform stents.

Prasugrel versus clopidogrel in stent-assisted coil embolization of unruptured intracranial aneurysms

Background Thromboembolic complications are the main problem in stent-assisted coil embolization of unruptured intracranial aneurysms. The combination of aspirin and clopidogrel is generally used to decrease these complications, but some patients do not respond to clopidogrel and have a higher risk of stent thrombosis. In cardiology, clinical trials have shown that prasugrel reduced the incidence of ischaemic events in patients with acute coronary syndrome compared with clopidogrel but, according to several authors, prasugrel would produce an increased risk of cerebral haemorrhagic complications. Objective The purpose of this study was to determine whether prasugrel would be more effective than clopidogrel in reducing procedural events in patients with an unruptured aneurysm treated endovascularly with coils and stent. Materials and methods Two hundred consecutive patients with intracranial aneurysms were treated using coiling and stenting procedures. The first 100 patients were administered a dual antiplatelet of aspirin and clopidogrel, while the remaining 100 patients were administered a dual antiplatelet of aspirin and prasugrel. In each group data were collected on procedural and periprocedural haemorrhagic and ischaemic complications. Results Aneurysmal occlusion and haemorrhagic complications rates were identical in both groups. The number of thromboembolic events observed in the two groups of our study did not differ significantly, but the prasugrel group included more wide-neck aneurysms and more flow-diverted stents. Moreover, complications in the prasugrel group were more benign, explaining the significant difference in clinical outcomes between the two groups on Day 30. Conclusions Prasugrel reduces the clinical consequences of thromboembolic complications of endovascular treatment with stenting and coiling of unruptured intracranial aneurysms.

The Silk flow-diverter stent for endovascular treatment of intracranial aneurysms

Flow diverter (FD) stents represent a new endovascular technique developed for the treatment of complex intracranial aneurysms (wide neck, fusiform, large, and giant aneurysms) that are challenging for classic endovascular techniques such as coiling, balloon-assisted coiling and stent-assisted coiling. Low porosity, high metal coverage, and high pore density are the main properties of FD stents. These properties induce hemodynamic changes redirecting the blood flow away from the aneurysm and into the parent artery leading to gradual thrombosis of the aneurysm. FD stents also provide scaffolding for subsequent neoendothelial proliferation, and vessel wall remodeling. This is considered as a paradigm shift compared to prior endovascular methods, which predominantly aimed at providing treatment inside the aneurysmal sac. This paper describes in detail the first released FD stent, the Silk flow-diverter stent (Balt Extrusion, Montmorency, France), its mechanism of action and deployment technique. It reviews the pertinent literature regarding safety, efficacy and potential risks and complications associated with the use of this stent.

Complications in Stent-Assisted Endovascular Therapy of Ruptured Intracranial Aneurysms and Relevance to Antiplatelet Administration: A Systematic Review

BACKGROUND AND PURPOSE

Despite the increasing use of stent-assisted coiling for ruptured intracranial aneurysms, there is little consensus regarding the appropriate antiplatelet administration for this. The objectives of this systematic review were to provide an overview of complications and their association with the method of antiplatelet administration in stent-assisted coiling for ruptured intracranial aneurysms.

MATERIALS AND METHODS

A comprehensive search of the literature in the data bases was conducted to identify studies reporting complications of stent-assisted coiling for ruptured intracranial aneurysms. The pooled event rate of preprocedural thromboembolisms, hemorrhages, and mortality was estimated from the selected studies. Subgroup analyses were performed by the method of antiplatelet administration (pre-, postprocedural, and modified). Meta-analysis was conducted to compare periprocedural complications and mortality between ruptured intracranial aneurysms and unruptured intracranial aneurysms.

RESULTS

Of the 8476 studies identified, 33 with 1090 patients were included. The event rates of thromboembolism and intra- and postprocedural hemorrhage were 11.2% (95% CI, 9.2%-13.6%), 5.4% (95% CI, 4.1%-7.2%), and 3.6% (95% CI, 2.6%-5.1%), respectively. Subgroup analyses of thromboembolism showed a statistically significant difference between groups (P < .05). In the preprocedural and modified antiplatelet groups, the risk for thromboembolism in stent-assisted coiling for ruptured intracranial aneurysm was not significantly different from that for unruptured intracranial aneurysm, though this risk of the postprocedural antiplatelet group was significantly higher in ruptured intracranial aneurysms than in unruptured intracranial aneurysms.

CONCLUSIONS

On the basis of current evidence, complications of stent-assisted coiling for ruptured intracranial aneurysm may be affected by the method of antiplatelet administration.

Differences in tissue proliferation and maturation between Matrix2 and bare platinum coil embolization in experimental swine aneurysms

BACKGROUND AND PURPOSE

Recanalization of post-embolization cerebral aneurysms remains a serious problem that influences treatment outcomes. Matrix2 is a bioactive, bio-absorbable, detachable coil that was developed to reduce the risk of recanalization. We examined the short-term efficacy of the Matrix2 coil system, and evaluated the temporal profile of tissue proliferation in a swine experimental aneurysm model compared with the bare platinum (BP) coil.

MATERIALS AND METHODS

Thirty-six experimental aneurysms were created in 18 swine. All aneurysms were tightly packed with Matrix2 or BP coils. Comparative histologic and morphologic analyses were undertaken 1, 2 and 4 weeks post-embolization.

RESULTS

Endothelial-like cells were observed partially lining the aneurysmal opening one week post-embolization with both coil types. At two and four weeks post-embolization, the aneurysms treated with Matrix2 coils had more extensive areas of organized thrombus than those packed with BP coils, but the numbers of functional proliferating endothelial cells identified by immunohistochemistry in the tissue were broadly comparable between the groups. Moreover, morphological analysis suggested there were more mature endothelial cells in aneurysms treated with bare platinum rather than Matrix2 coils.

CONCLUSIONS

Our results indicate that aneurysms embolized with Matrix2 coils build thicker scaffolds for endothelialization, but this is not necessarily evidence of earlier tissue proliferation and maturation than those embolized with BP coils. Matrix2 coils may not be superior to BP coils for preventing aneurysmal recanalization after endovascular treatment of cerebral aneurysms.

Stent-assisted Coil Placement for the Treatment of 211 Acutely Ruptured Wide-necked Intracranial Aneurysms: A Single-Center 11-Year Experience

PURPOSE

To evaluate the safety and angiographic and clinical outcome of stent-assisted coil placement (SACP) for acutely ruptured wide-necked intracranial aneurysms treated in a single center during an 11-year period.

MATERIALS AND METHODS

According to an institutional review board-approved protocol, the angiographic and clinical data of 211 patients (52 men, 159 women; median age, 56 years; age range, 31-83 years) with acutely ruptured wide-necked intracranial aneurysms (neck > 4 mm and/or dome-to-neck ratio ≤ 2) treated with SACP from September 2000 to December 2011 were reviewed retrospectively. Baseline characteristics, procedure-related complications, angiographic follow-up results, and clinical outcome were analyzed statistically. A Mann-Whitney U test was performed for non-normally distributed continuous variables. A Pearson χ(2) or Fisher exact test was performed for categorical variables. Univariate analysis and logistic regression analysis were performed to determine the association of procedure-related complications and clinical outcome with potential risk factors.

RESULTS

Procedure-related complications occurred in 30 patients (14.2%). They were more common in the anterior communicating artery (26.7%, 12 of 45) and middle cerebral artery bifurcation (40%, four of 10) aneurysms than in aneurysms at other locations (9.0%, 14 of 156). Clinical outcome (median, 33 months) was good in 175 patients (82.9%) with a modified Rankin Scale score of up to 2. Older age (P = .013, odds ratio = 1.054) and higher Hunt and Hess grade (P < .001, odds ratio = 15.876) were independent risk factors for unfavorable outcome. One hundred fifty-two of 190 patients who survived (80%) underwent angiographic follow-up at least once (median, 12 months). The complete occlusion rate improved from an immediate 45.5% to 75.7% at follow-up (115 of 152 patients).

CONCLUSION

Angiographic and clinical outcomes in our series were comparable to those reported by using coil placement alone or balloon-assisted coil placement techniques. SACP for the treatment of acutely ruptured middle cerebral artery bifurcation and anterior communicating artery aneurysms was associated with a significantly higher incidence of complications than was the case for treatment of aneurysms at other locations.

Enterprise stent-assisted coiling for wide-necked intracranial aneurysms during ultra-early (48hours) subarachnoid hemorrhage: a single-center experience in 59 consecutive patients

BACKGROUND AND OBJECTIVE

Accumulated experience and improvement of stents dedicated to intracranial use have significantly widened the applicability of stent-assisted coiling (SAC) to ruptured wide-necked aneurysms. This retrospective study was designed to evaluate the safety and efficacy of SAC using the Enterprise stent for ruptured wide-necked intracranial aneurysms during ultra-early subarachnoid hemorrhage.

METHOD

We reviewed data from 59 consecutive patients with ruptured wide-necked aneurysms who had SAC using the Enterprise stent performed within 48hours of onset. Data collected and analyzed included: patient demographics; morphologic features of the aneurysm; treatment results and follow-up results. Clinical outcomes were evaluated by modified Rankin Scale (mRS).

RESULTS

In all 59 cases, SAC using the Enterprise stent was performed successfully, with no significant technical difficulties. Initial angiographic results were: complete occlusion in 38 cases; near occlusion in 17; and partial occlusion in four. Angiographic follow-up of 48 patients showed that 46 (95.8%) remained stable or improved, without regrowth, while regrowth was imaged in two patients. Medium-term clinical follow-up of 54 patients (mean, 26.9months) showed that 88.9% had a good outcome (mRS: 0 in 34; 1 in eight; and 2 in six), and 11.1% poor outcomes (mRS: 3 in four; and 4 in two).

CONCLUSION

Enterprise SAC is a safe and viable option for treatment of ruptured wide-necked aneurysms within 48hours of ictus.

Assessing Blood Flow in an Intracranial Stent: A Feasibility Study of MR Angiography Using a Silent Scan after Stent-Assisted Coil Embolization for Anterior Circulation Aneurysms

BACKGROUND AND PURPOSE

Blood flow in an intracranial stent cannot be visualized with 3D time-of-flight MR angiography owing to magnetic susceptibility and radiofrequency shielding. As a novel follow-up tool after stent-assisted coil embolization, we applied MRA by using a Silent Scan algorithm that contains an ultrashort TE combined with an arterial spin-labeling technique (Silent MRA). The purpose of this study was to determine whether Silent MRA could visualize flow in an intracranial stent placed in the anterior circulation.

MATERIALS AND METHODS

Nine patients treated with stent-assisted coil embolization for anterior circulation aneurysms underwent MRAs (Silent MRA and TOF MRA) and x-ray digital subtraction angiography. MRAs were performed in the same session on a 3T unit. Two neuroradiologists independently reviewed the MRA images and subjectively scored flow in a stent as 1 (not visible) to 4 (excellent) by referring to the latest x-ray digital subtraction angiography image as a criterion standard.

RESULTS

Both observers gave MRA higher scores than TOF MRA for flow in a stent in all cases. The mean score for Silent MRA was 3.44 ± 0.53, and for TOF MRA, it was 1.44 ± 0.46 (P < .001).

CONCLUSIONS

Silent MRA was able to visualize flow in an intracranial stent more effectively than TOF MRA. Silent MRA might be useful for follow-up imaging after stent-assisted coil embolization, though these study results may be only preliminary due to some limitations.

Assisted coiling of saccular wide-necked unruptured intracranial aneurysms: stent versus balloon

BACKGROUND AND PURPOSE

Assisted coiling with stents or balloons enables a higher percentage of complete occlusions of saccular unruptured intracranial aneurysms to be achieved with a reasonable complication rate. The aim of this study was to compare stent-assisted coiling and the balloon remodeling technique in terms of efficacy, stability, and safety for the treatment of comparable unruptured saccular intracranial aneurysms.

MATERIALS AND METHODS

268 patients with 286 saccular unruptured wide-necked intracranial aneurysms were treated at our institution with stent- or balloon-assisted coiling and retrospectively reviewed. Statistical analysis was performed to assess significant differences between the two groups.

RESULTS

The rate of complete occlusion at the end of the procedure was higher with stent-assisted coiling than with balloon-assisted coiling (86.8% vs 78%) and the same results were also observed after 6 months (92.1% vs 77.6%; p=0.05). About 50% of major recurrences occurred in large to giant aneurysms (p<0.001). The overall complication rate was similar in the stent-assisted and balloon-assisted groups (10.3% vs 9.3%). Independently of the technique, a higher complication rate was observed with bifurcational aneurysms, particularly in the middle cerebral artery (p=0.016).

CONCLUSIONS

Stent-assisted coiling achieved better results in terms of complete occlusion and stability than balloon-assisted coiling with a lower rate of recurrence without being associated with a higher risk of intraprocedural complications. Bifurcational and large to giant aneurysms were associated with higher complication rates and higher recurrence rates, respectively, and still represent a challenge for both techniques.