Endovascular Coiling versus Surgical Clipping for Poor-Grade Ruptured Intracranial Aneurysms: Postoperative Complications and Clinical Outcome in a Multicenter Poor-Grade Aneurysm Study

BACKGROUND AND PURPOSE:Endovascular coiling is an alternative to surgical clipping for ruptured intracranial aneurysms. However, no large multicenter prospective study has compared coiling and clipping in patients with poor-grade ruptured aneurysms. We aimed to determine differences in postoperative complications and clinical outcome between the 2 treatments in this group of patients.MATERIALS AND METHODS:A Multicenter Poor-Grade Aneurysm Study was a prospective, multicenter, observational registry of consecutive patients who presented with poor-grade ruptured aneurysms. Three hundred sixty-six patients were enrolled from October 2010 to March 2012. “Poor-grade aneurysm” was defined as a World Federation of Neurosurgical Societies grade of IV or V at the time of aneurysm treatment. Two hundred sixty-two patients received aneurysm treatment within 21 days and were included. Clinical outcomes were assessed at discharge and at 6 and 12 months by the modified Rankin Scale.RESULTS:One hundred thirty-three (50.8%) patients underwent endovascular coiling. Unadjusted analysis showed that the outcome rate (mRS 0–1 or mRS 0–2) at 6 and 12 months in patients undergoing coiling was higher than that in patients undergoing clipping. In adjusted analyses, there was no statistically significant difference in outcomes at 6 and 12 months between the 2 groups. The risk of radiologic hydrocephalus was higher in patients treated with coiling than that in those treated with clipping (adjusted OR, 3.36; 95% CI, 1.13–10.01; P = .030).CONCLUSIONS:The long-term outcome in selected patients was similar between endovascular coiling and clipping for poor-grade ruptured aneurysms. The risk of radiologic hydrocephalus was higher after endovascular treatment of poor-grade aneurysms.

Intracranial aneurysm rupture leading to aneurysmal subarachnoid hemorrhage (aSAH) is a devastating condition. Poor-grade ruptured aneurysms account for approximately 30% of all cases of aSAH.^1,2 Traditionally, patients with poor-grade aneurysms have been managed medically. In the past 2 decades, aggressive treatment has been proposed to improve outcomes in selected patients.^1,3,4 Despite recent advances in the treatment of aSAH, patients with poor-grade aneurysms have high rates of long-term morbidity and mortality.^1,3–6The International Subarachnoid Aneurysm Trial (ISAT) has demonstrated that for ruptured aneurysms suitable for endovascular embolization and clipping, patients treated with coiling had better outcomes than those treated with clipping.^7,8 However, only a few patients (4.4%) in ISAT had poor-grade aneurysms. The results may not directly apply to poor-grade patients. Currently, case series have shown that endovascular coiling is a viable alternative to clipping for poor-grade aneurysms.^5,9,10 However, to date, no randomized, controlled study has been performed to evaluate the efficacy of coiling versus clipping for poor-grade ruptured aneurysms, to our knowledge. There has been no large multicenter prospective study regarding the effects of different treatments on postoperative complications and clinical outcome in these patients.A Multicenter Poor-Grade Aneurysm Study (AMPAS) was a prospective, multicenter, observational registry of consecutive patients who presented with poor-grade ruptured aneurysm.¹¹ The primary purpose of this report was to determine differences in postoperative complications and clinical outcome between patients treated with coiling and those treated with clipping in the AMPAS after adjustment for differences in baseline confounders.     

Safety and Efficacy of Stent-Assisted Coiling of Unruptured Intracranial Aneurysms Using Low-Profile Stents in Small Parent Arteries

BACKGROUND AND PURPOSE:Stent-assisted coiling of intracranial aneurysms arising from small vessels (≤ 2.0 mm) is a common procedure. However, data regarding its treatment outcomes are scarce. This study evaluated the clinical and radiologic outcomes of stent-assisted coiling using low-profile stents for aneurysms of small parent arteries.MATERIALS AND METHODS:From November 2015 to October 2020, sixty-four patients with 66 aneurysms arising from parent arteries of ≤2.0 mm were treated with stent-assisted coiling using a Low-Profile Visualized Intraluminal Support Junior (LVIS Jr) or the Neuroform Atlas stent in a single institution. The clinical and radiologic data were retrospectively reviewed, and the risk factors for procedure-related complications were evaluated.RESULTS:The LVIS Jr and Neuroform Atlas stents were used in 22 (33.3%) and 44 (66.7%) cases, respectively. Technical success was achieved in 66 cases (100%). Immediate postprocedural aneurysm occlusion grades assessed by the Raymond-Roy occlusion classification were I (57.6%), II (19.7%), and III (22.7%), respectively. Procedure-related complications occurred in 10 cases (15.2%), with 8 thromboembolic complications (12.1%) and 2 hemorrhagic complications (3.0%). Procedure-related morbidity was 4.5% without mortality. On multivariate analysis, current smoking (odds ratio = 7.1, P = .021) had a statistically significant effect on procedure-related complications.CONCLUSIONS:Stent-assisted coiling of intracranial aneurysms with low-profile stents in small vessels (≤ 2.0 mm) had a 100% success rate and a 15.2% overall complication rate with 4.5% morbidity. Current smoking was a significant risk factor associated with procedure-related complications.

In the past decade, development in neuroendovascular devices and techniques has facilitated the successful treatment of intracranial aneurysms that had been previously considered challenging or uncoilable lesions.¹ Above all, stent-assisted coiling (SAC) is widely accepted as an effective and safe treatment technique for wide-neck intracranial aneurysms^2,3 because it can also reduce recanalization and retreatment rates.⁴ However, previously used stent placement in small vessels was technically challenging due to the difficult navigation of larger (0.021- or 0.027-inch) delivery microcatheters to these small arteries.^5-7Recently, low-profile stents were introduced to improve the navigability and success rate of the procedure because they can be delivered via 0.0165- or 0.017-inch microcatheters to access tortuous and smaller vessels.^8-10 Although the recommended use of the low-profile stents is for a parent artery with a diameter of either ≥2.0  or ≥2.5 mm, their off-label use for the treatment of aneurysms arising from smaller parent arteries has become more common.^11,12 However, little is known about the efficacy and safety of SAC using low-profile stents in vessels smaller than 2.0 mm.In the present study, we aimed to investigate the clinical and radiologic outcomes of SAC using low-profile stents for the treatment of unruptured intracranial aneurysms arising from small vessels with a diameter of ≤2.0 mm.     

Treatment of Multiple Intracranial Aneurysms with 1-Stage Coiling

BACKGROUND AND PURPOSE:Although multiple intracranial aneurysms are frequent, determining treatment strategy and methods for them is often complicated. The aim of this study was to evaluate the safety and effectiveness of 1-stage coiling for multiple intracranial aneurysms.MATERIALS AND METHODS:All patients who underwent 1-stage coiling for ≥2 aneurysms were identified from a prospectively registered neurointerventional data base during 10 years. The patient characteristics and clinical and angiographic outcomes at discharge and follow-up were retrospectively evaluated.RESULTS:One hundred sixty-seven patients (male/female ratio, 30:137; mean age, 58 years) with multiple aneurysms (418 aneurysms; mean, 2.5 aneurysms/patient) underwent attempted 1-stage coiling for ≥2 aneurysms (359 aneurysms; mean, 2.1 aneurysms/patient). In 131 patients (78.4%), all detected aneurysms were treated with coiling only. Treatment-related morbidity and mortality at discharge were 1.8% and 0.6% per patient, respectively. Of the 132 patients without subarachnoid hemorrhage, 129 (97.7%) had favorable outcomes (mRS 0–2) at discharge; of the 35 patients with SAH, 27 (77.1%) had favorable outcomes at discharge. Of the 162 patients (97%) for whom clinical follow-up was available (mean, 35.8 months), 154 patients (95.1%) had favorable outcomes. Immediate posttreatment angiography showed complete occlusion in 186 (51.8%) aneurysms, neck remnants in 134 (37.3%), sac remnants in 33 (9.2%), and failure in 6 (1.7%). Of the 262 (73.9%) aneurysms that underwent follow-up imaging (mean, 24.8 months), 244 (93.1%) showed a stable or improved state, with 12 (4.6%) minor and 6 (2.3%) major recurrences.CONCLUSIONS:One-stage coiling of multiple aneurysms seems to be safe and effective, with low morbidity and mortality.

Intracranial aneurysm is the most important cause of subarachnoid hemorrhage, resulting in 8%–20% dependent morbidity and 37%–57% mortality.¹ Strategies and methods for treating intracranial aneurysms have been extensively studied. Multiple intracranial aneurysms are frequent, with a reported incidence of 19%–34% of patients who present with SAH.^2–5 Determining treatment strategy and methods for multiple aneurysms is often complicated. Coiling is currently accepted as a standard treatment for ruptured or unruptured intracranial aneurysms and has been increasingly used, regardless of the location of the intracranial aneurysm.⁶ Nevertheless, while many cases of clipping for multiple aneurysms have been reported,^7–12 there were only 2 small case series using coiling for multiple aneurysms.^13,14 The purpose of this study was to evaluate the safety and effectiveness of 1-stage coiling for multiple intracranial aneurysms.     

Comparative Effectiveness of Ruptured Cerebral Aneurysm Therapies: Propensity Score Analysis of Clipping versus Coiling

BACKGROUND AND PURPOSE:The relative merits of treating ruptured aneurysms with clipping versus coiling continue to be a topic of debate. We evaluated a national, multihospital patient data base to examine recent trends in ruptured aneurysm therapies and to compare peri-procedural outcomes between clipping and coiling treatments.MATERIALS AND METHODS:The Premier Perspective data base was used to identify patients hospitalized between 2006–2011 for ruptured aneurysm who underwent clipping or coiling therapy. A propensity score model, representing the probability of receiving clipping, was generated for each patient by use of relevant patient and hospital variables. After Greedy-type matching of the propensity score, the risk of in-hospital mortality and morbidity was compared between clipping and coiling cohorts.RESULTS:A total of 5229 patients with ruptured aneurysm (1228 clipping, 4001 coiling) treated at 125 hospitals were identified. Clipping therapy frequency decreased from 27% in 2006 to 21% in 2011. After propensity score adjustment, in-hospital mortality risk was similar between groups (OR = 0.94 [95% CI, 0.73–1.21]; P = .62). However, unfavorable outcomes were more common after clipping compared with coiling, including discharge to long-term care (OR = 1.32 [95% CI, 1.12–1.56]; P = .0006), ischemic complications (OR = 1.51 [95% CI, 1.24–1.83]; P = .0009), neurologic complications (OR = 1.64 [95% CI, 1.18–2.27]; P = .0018), and other surgical complications (OR = 1.55 [95% CI, 1.05–2.33]; P = .0240).CONCLUSIONS:This study of a data base of multiple hospitals in the United States demonstrates that clipping of ruptured cerebral aneurysms resulted in greater adjusted morbidity compared with coiling.

The relative merits of treating ruptured aneurysms with clipping versus coiling continue to be a topic of debate. The International Subarachnoid Aneurysm Trial (ISAT) demonstrated a 7.4% decrease in absolute risk of death or dependency (modified Rankin score, 4–5) at 1 year, with 23.5% of patients randomly assigned to coiling dependent or dead at 1 year compared with 30.9% randomly assigned to clipping.¹ However, because ISAT only enrolled patients who were deemed suitable to receive either clipping or coiling therapy, representing only 22% of patients who were screened,² the generalizability of the results has been called into question.³ Despite this criticism, multiple reports show a trend toward increasing use of coiling over clipping for patients with ruptured cerebral aneurysms.^4–7 Studies of large patient data bases that compared clipping and coiling treatments yielded mixed results, with some demonstrating worse outcomes after clipping^8,9 and others demonstrating worse outcomes after coiling.^6,10 In addition, the nonrandomized studies may have been affected by selection bias. To address this disparity in study findings and the concern of potential selection bias, we identified patients hospitalized for ruptured cerebral aneurysm between 2006–2011 by use of a large multihospital data base and performed a propensity score analysis to compare peri-procedural outcomes between patients of similar clinical and demographic characteristics who were treated with clipping or coiling.     

Pipeline Embolization Device in the Treatment of Recurrent Previously Stented Cerebral Aneurysms

BACKGROUND AND PURPOSE:The use of the Pipeline Embolization Device in the management of recurrent previously stented cerebral aneurysms is controversial. The aim of this study was to evaluate the efficacy and safety of the Pipeline Embolization Device in the treatment of recurrent, previously stented aneurysms.MATERIALS AND METHODS:Twenty-one patients with previously stented recurrent aneurysms who later underwent Pipeline Embolization Device placement (group 1) were retrospectively identified and compared with 63 patients who had treatment with the Pipeline Embolization Device with no prior stent placement (group 2). Occlusion at the latest follow-up angiogram, recurrence and retreatment rates, clinical outcome, complications, and morbidity and mortality observed after treatment with the Pipeline Embolization Device were analyzed.RESULTS:Patient characteristics were similar between the 2 groups. The mean time from stent placement to recurrence was 25 months. Pipeline Embolization Device treatment resulted in complete aneurysm occlusion in 55.6% of patients in group 1 versus 80.4% of patients in group 2 (P = .036). The retreatment rate in group 1 was 11.1% versus 7.1% in group 2 (P = .62). The rate of good clinical outcome at the latest follow-up in group 1 was 81% versus 93.2% in group 2 (P = .1). Complications were observed in 14.3% of patients in group 1 and 9.5% of patients in group 2 (P = .684).CONCLUSIONS:The use of the Pipeline Embolization Device in the management of previously stented aneurysms is less effective than the use of this device in nonstented aneurysms. Prior stent placement can worsen the safety and efficacy profile of this device.

Since the introduction of detachable coils, cerebral aneurysm management has shifted considerably toward endovascular treatment. One of the main weaknesses of cerebral aneurysm coiling lies in the treatment of patients with large^1,2 wide-neck or fusiform aneurysms.³ These aneurysms tend to have higher recurrence and retreatment rates after coiling. To make up for this deficiency, intracranial stents have emerged as an alternative in the management of this type of aneurysm. The most widely used stents include the Neuroform (Stryker Neurovascular, Kalamazoo, Michigan) and Enterprise self-expanding (Codman & Shurtleff, Raynham, Massachusetts) stents, which were approved for use as Humanitarian Use Devices in 2002 and 2007, respectively. Several techniques can be used with stents, including stent placement alone and stent-assisted coiling. Recanalization and retreatment rates are lower with stent placement and stent-assisted coiling than with coiling alone.^4–6 However, the initial occlusion rates are suboptimal, particularly in large aneurysms.^7,8The management of recurrent previously stented aneurysms remains controversial. There are no recommendations to indicate the most appropriate management strategy, to our knowledge. In 2011, the Pipeline Embolization Device (PED; Covidien, Irvine, California) was FDA-approved for the treatment of large and giant wide-neck aneurysms in the internal carotid artery, from the petrous to the superior hypophyseal segments.⁹ The PED belongs to a family of devices known as flow diverters, which work by acting as a scaffold for endothelial overgrowth of the aneurysm neck.¹⁰ The main structural differences from previous stents are the higher metal surface area coverage compared with previous stents and the low porosity, which allows more flow reduction into the aneurysm neck.^11,12 The overall use of the PED has gained popularity mainly because of its high success rate in achieving aneurysm occlusion and low aneurysm recurrence and retreatment rates, especially compared with other endovascular interventions.^13,14 Early reports have questioned the efficacy and safety of the PED in treating previously stented aneurysms.^15–17 The aim of this study was to evaluate the role of the PED, both its efficacy and safety, in the treatment of recurrent, previously stented cerebral aneurysms.     

Contrast-Enhanced and Time-of-Flight MRA at 3T Compared with DSA for the Follow-Up of Intracranial Aneurysms Treated with the WEB Device

BACKGROUND AND PURPOSE:Imaging follow-up at 3T of intracranial aneurysms treated with the WEB Device has not been evaluated yet. Our aim was to assess the diagnostic accuracy of 3D–time-of-flight MRA and contrast-enhanced MRA at 3T against DSA, as the criterion standard, for the follow-up of aneurysms treated with the Woven EndoBridge (WEB) system.MATERIALS AND METHODS:From June 2011 to December 2014, patients treated with the WEB in our institution, then followed for ≥6 months after treatment by MRA at 3T (3D-TOF-MRA and contrast-enhanced MRA) and DSA within 48 hours were included. Aneurysm occlusion was assessed with a simplified 2-grade scale (adequate occlusion [total occlusion + neck remnant] versus aneurysm remnant). Interobserver and intermodality agreement was evaluated by calculating the linear weighted κ. MRA test characteristics and predictive values were calculated from a 2 × 2 contingency table, by using DSA data as the standard of reference.RESULTS:Twenty-six patients with 26 WEB-treated aneurysms were included. The interobserver reproducibility was good with DSA (κ = 0.71) and contrast-enhanced-MRA (κ = 0.65) compared with moderate with 3D-TOF-MRA (κ = 0.47). Intermodality agreement with DSA was fair with both contrast-enhanced MRA (κ = 0.36) and 3D-TOF-MRA (κ = 0.36) for the evaluation of total occlusion. For aneurysm remnant detection, the prevalence was low (15%), on the basis of DSA, and both MRA techniques showed low sensitivity (25%), high specificity (100%), very good positive predictive value (100%), and very good negative predictive value (88%).CONCLUSIONS:Despite acceptable interobserver reproducibility and predictive values, the low sensitivity of contrast-enhanced MRA and 3D-TOF-MRA for aneurysm remnant detection suggests that MRA is a useful screening procedure for WEB-treated aneurysms, but similar to stents and flow diverters, DSA remains the criterion standard for follow-up.

Endovascular treatment is now the first-line treatment for the management of ruptured and unruptured intracranial aneurysms.^1–4 However, the limitations of standard coiling for complex aneurysms (large, wide-neck, or developed in a bifurcation) have contributed to the development of new endovascular approaches, including balloon-assisted coiling, stent-assisted coiling, flow diversion, and flow disruption.⁵The Woven EndoBridge (WEB) aneurysm embolization system (Sequent Medical, Aliso Viejo, California) is an intrasaccular device designed to disrupt the intra-aneurysmal flow at the level of the neck.^6,7 Initial experience with the WEB–Dual-Layer (DL) showed the clinical utility of this device in wide-neck bifurcation aneurysms with high technical success and low acute morbidity and mortality.^6–16 Several WEB devices are now available, including Single-Layer (WEB-SL), Single-Layer Sphere (WEB-SLS), and WEB-DL subtypes.^12,13 Recently, Enhanced-Visualization (EV) versions were developed to improve fluoroscopic visualization of the devices during treatment.Because of the potential risk of aneurysm recanalization after endovascular treatment, regular imaging follow-up is recommended. Digital subtraction angiography is the criterion standard for the follow-up of intracranial aneurysms after endovascular treatment but has some disadvantages, including potential neurologic complications, iodinated contrast injection, and radiation exposure. With the goal of avoiding DSA drawbacks, several MR angiography techniques have been tested to follow intracranial aneurysms. 3D-TOF-MRA and contrast-enhanced MRA (CE-MRA) at 3T are appropriate techniques for the follow-up of coiled aneurysms but have some limitations for the aneurysms treated with stents or flow diverters.^17–23 Because the WEB is a relatively new device, the value of 3D-TOF-MRA and CE-MRA for the follow-up of WEB-treated intracranial aneurysms has been evaluated in a small number of patients at 1.5T.²⁴The aim of this single-center prospective study was to assess the diagnostic accuracy of 3D-TOF-MRA and CE-MRA at 3T against DSA, as the criterion standard, for the evaluation of aneurysm occlusion after WEB treatment.     

Preliminary Experience with Stent-Assisted Coiling of Aneurysms Arising from Small (<2.5 mm) Cerebral Vessels Using The Low-Profile Visualized Intraluminal Support Device

BACKGROUND AND PURPOSE:The Low-Profile Visualized Intraluminal Support (LVIS) stent is a new device recently introduced for the treatment of wide-neck intracranial aneurysms. This single-center study presents the authors'' preliminary experience using the LVIS stent to treat saccular aneurysms with parent arteries smaller than 2.5 mm.MATERIALS AND METHODS:Aneurysms with a LVIS stent used in a small parent vessel (<2.5 mm in diameter) between October 2014 and April 2016 were included. Procedure-related complications, angiographic results, clinical outcomes, and midterm follow-up data were analyzed retrospectively.RESULTS:A total of 22 patients was studied, including 5 ruptured and 17 unruptured aneurysms. Most of the aneurysms were located in the anterior circulation (90.9%). Stent placement in the parent arteries measuring 1.7–2.4 mm in diameter (mean, 2.1 mm) was successful in 100% of cases. Procedure-related complication developed in 1 patient (4.5%) who presented with aneurysm rupture. No permanent morbidity and mortality occurred. Immediate angiographic outcome showed complete occlusion in 8 aneurysms (36.4%), neck residual in 8 (36.4%), and residual aneurysm in 6 (27.3%). All patients underwent angiographic follow-up at a mean of 8.3 months, which revealed complete occlusion in 18 (81.8%) patients, neck remnant in 3 (13.6%), and residual sac in 1 (4.5%). No recanalization of the target aneurysm was observed. There was 1 case with asymptomatic in-stent stenosis.CONCLUSIONS:Our preliminary results show that the deployment of LVIS stents in small vessels is feasible, safe, and effective in the midterm. Larger studies with long-term follow-up are needed to validate our promising results.

The introduction of stent devices has greatly advanced the endovascular treatment options of intracranial aneurysms. Many aneurysms that had been previously considered untreatable because of their morphology, including those with unfavorable dome-to-neck ratios and/or location, are now amenable to coiling with the use of stents.^1,2 However, the use of stents for treating wide-neck distal intracranial aneurysms with small parent vessels remains challenging. Several previous studies reported relatively high rates of periprocedural thromboembolic events and in-stent stenosis.^3–11The Low-Profile Visualized Intraluminal Support (LVIS) device (MicroVention, Tustin, California), a new device offering an option between conventional stents and flow diverters, is designed for the stent-assisted coil embolization of wide-neck intracranial aneurysms. There is an increasing number of publications on the use of the LVIS device.^12–16 However, to our knowledge, no studies to date have specifically investigated the placement of the LVIS device in small vessels. Hence, we conducted this retrospective study to examine the LVIS device in terms of its safety, deployment feasibility, and treatment effectiveness in intracranial aneurysms with parent vessels measuring <2.5 mm in diameter.     

Association between Postprocedural Infarction and Antiplatelet Drug Resistance after Coiling for Unruptured Intracranial Aneurysms

BACKGROUND AND PURPOSE:Procedure-related thromboembolism is a major limitation of coil embolization, but the relationship between thromboembolic infarction and antiplatelet resistance is poorly understood. The purpose of this study was to verify the association between immediate postprocedural thromboembolic infarction and antiplatelet drug resistance after endovascular coil embolization for unruptured intracranial aneurysm.MATERIALS AND METHODS:This study included 338 aneurysms between October 2012 and March 2015. All patients underwent postprocedural MR imaging within 48 hours after endovascular coil embolization. Antiplatelet drug resistance was checked a day before the procedure by using the VerifyNow system. Abnormal antiplatelet response was defined as >550 aspirin response units and >240 P2Y12 receptor reaction units. In addition, we explored the optimal cutoff values of aspirin response units and P2Y12 receptor reaction units. The primary outcome was radiologic infarction based on postprocedural MR imaging.RESULTS:Among 338 unruptured intracranial aneurysms, 134 (39.6%) showed diffusion-positive lesions on postprocedural MR imaging, and 32 (9.5%) and 105 (31.1%) had abnormal aspirin response unit and P2Y12 receptor reaction unit values, respectively. Radiologic infarction was associated with advanced age (65 years and older, P = .024) only with defined abnormal antiplatelet response (aspirin response units ≥ 550, P2Y12 receptor reaction units ≥ 240). P2Y12 receptor reaction unit values in the top 10th percentile (>294) were associated with radiologic infarction (P = .003). With this cutoff value, age (adjusted odds ratio, 2.29; 95% confidence interval, 1.28–4.08), P2Y12 receptor reaction units (>294; OR, 3.43; 95% CI, 1.53–7.71), and hyperlipidemia (OR, 2.05; 95% CI, 1.04–4.02) were associated with radiologic infarction in multivariate analysis.CONCLUSIONS:Radiologic infarction after coiling for unruptured aneurysm was closely associated with age. Only very high P2Y12 receptor reaction unit values (>294) predicted postprocedural infarction. Further controlled studies are needed to determine the precise cutoff values, which could provide information regarding the optimal antiplatelet regimen for aneurysm coiling.

Endovascular coil embolization is a well-established treatment method for intracranial aneurysms. Recent evidence suggests that this procedure can be considered a first-line treatment for both ruptured and unruptured intracranial aneurysms.^1,2 However, endovascular coil embolization still has major drawbacks, including procedural rupture, thromboembolic complications, and durability issues. Among these shortcomings, thromboembolism is the most common problem.^3–5 To reduce thromboembolic complications, many studies investigated the association between thromboembolism and aneurysm and/or patient factors.^5–8 Previous studies have demonstrated that 30%–60% of endovascular coil embolizations for unruptured aneurysms show ischemic lesions on postprocedural diffusion-weighted images. Although most of the lesions seem to be benign, some could result in permanent neurologic sequelae. Recent studies demonstrated that antiplatelet resistance was associated with ischemic complications after coil embolization and that drug adjustment could lower the risk.^9,10 Still, these results are controversial, and the association between antiplatelet drug resistance and diffusion lesions has not yet been fully elucidated.^11,12Therefore, the purpose of this study was to verify the association between thromboembolic infarction and antiplatelet drug resistance after endovascular coil embolization for unruptured intracranial aneurysms. We also explored other risk factors for thromboembolic complications.     

Autosomal Dominant Polycystic Kidney Disease and Intracranial Aneurysms: Is There an Increased Risk of Treatment?

BACKGROUND AND PURPOSE:Autosomal dominant polycystic kidney disease is associated with an increased risk of intracranial aneurysms. Our purpose was to assess whether there is an increased risk during aneurysm coiling and clipping.MATERIALS AND METHODS:Data were obtained from the National Inpatient Sample (2000–2011). All subjects had an unruptured aneurysm clipped or coiled and were divided into polycystic kidney (n = 189) and control (n = 3555) groups. Primary end points included in-hospital mortality, length of stay, and total hospital charges. Secondary end points included the International Classification of Diseases, Ninth Revision codes for iatrogenic hemorrhage or infarction; intracranial hemorrhage; embolic infarction; and carotid and vertebral artery dissections.RESULTS:There was a significantly greater incidence of iatrogenic hemorrhage or infarction, embolic infarction, and carotid artery dissection in the patients with polycystic kidney disease compared with the control group after endovascular coiling. There was also a significantly greater incidence of iatrogenic hemorrhage or infarction in the polycystic kidney group after surgical clipping. However, the hospital stay was not longer in the polycystic kidney group, and the total hospital charges were not higher. Additional analysis within the polycystic kidney group revealed a significantly shorter length of stay but similar in-hospital costs when subjects underwent coiling versus clipping.CONCLUSIONS:Patients with polycystic kidney disease face an increased risk during intracranial aneurysm treatment, whether by coiling or clipping. This risk, however, does not translate into longer hospital stays or increased hospital costs. Despite the additional catheterization-related risks of dissection and embolization, coiling results in shorter hospital stays and similar mortality compared with clipping.

Autosomal dominant polycystic kidney disease (ADPCKD) is a genetic disorder affecting 1 in 1000 individuals worldwide and is associated with an increased risk of intracranial aneurysms, ranging from 4% to 23%^1–6 compared with the general population risk of 2%–3%.^7–10 Patients with ADPCKD are also at increased risk for aneurysm rupture earlier in life (mean age, 35–45 years),^1,11–13 compared with the general population (mean age, 50–54 years).^14,15There is evidence that the associated vascular defects in ADPCKD may be due to mutations in the PKD1 and PKD2 genes, located on the short arm of chromosomes 16 and 4.^16,17 Abnormalities of these genes in mouse models correspond with increased rates of arterial dissection, arterial rupture, and intracranial vascular abnormalities.¹⁸ To our knowledge, only 1 study to date has investigated whether these issues engender an increased risk when treating intracranial aneurysms (whether by endovascular coiling or surgical clipping).² The purpose of this investigation was to assess whether ADPCKD confers an increased peri- and immediate postprocedural risk of aneurysm coiling and clipping.     

Effects of Circle of Willis Anatomic Variations on Angiographic and Clinical Outcomes of Coiled Anterior Communicating Artery Aneurysms

BACKGROUND AND PURPOSE:Anterior communicating artery aneurysms account for one-fourth of all intracranial aneurysms and frequently occur in the context of A1 vessel asymmetry. The purpose of this study was to correlate circle of Willis anatomic variation association to angiographic and clinical outcomes of anterior communicating aneurysm coiling.MATERIALS AND METHODS:The Cerecyte Coil Trial provides a subgroup of 124 cases with anterior communicating artery aneurysms after endovascular coiling. One hundred seventeen of 124 anterior communicating artery aneurysms had complete imaging and follow-up for clinical outcome analysis, stability of aneurysm coil packing, and follow-up imaging between 5 and 7 months after treatment. Clinical outcomes were assessed by the mRS at 6 months.RESULTS:Anterior cerebral artery trunk-dominance was seen in 91 of 124 (73%) anterior communicating artery aneurysms and codominance in 33 of 124 (27%) anterior communicating artery aneurysms. There was no significant difference (P > .5) in treatment success at 5–7 months for anterior communicating artery aneurysms between the anterior cerebral artery trunk-dominant (49 of 86, 57%) and anterior cerebral artery trunk-codominant (19 of 31) groups. Angiographic follow-up demonstrates a statistically significant increase in neck remnants and progressive aneurysm sac filling with the A1 dominant configuration (n = 21, 24% at follow-up versus n = 11, 12% at immediate posttreatment, P = .035). There was no statistically significant difference in clinical outcomes between types of anterior cerebral artery trunk configuration (P > .5).CONCLUSIONS:Anterior communicating artery aneurysms with anterior cerebral artery trunk-dominant circle of Willis configurations show less angiographic stability at follow-up than those with anterior cerebral artery trunk-codominance similar to other “termination” type aneurysms. This supports the hypothesis that anterior cerebral artery trunk-dominant flow contributes to aneurysm formation, growth, and instability after coiling treatment.

The most common site of intracranial aneurysms is the anterior communicating artery (AcomA). AcomA aneurysms account for approximately one-fourth of all intracranial aneurysms.¹ Also very common in the setting of AcomA aneurysms is unilateral anterior cerebral artery trunk (A1) dominance where 1 side supplies both pericallosal artery (A2) arteries, a well-known phenomenon previously shown to be a potent risk factor for AcomA aneurysm formation and rupture.^1–3To what extent vessel dominance influences the long-term result of endovascular packing of these aneurysms with detachable platinum coils and the patients'' clinical outcome is less well known.^4–6 One previous study indicates that vessel dominance is not a major factor in predicting short-term treatment outcome; however, the methodology and definition of vessel dominance as used in this instance was not stated.⁷ Yet, anterior communicating aneurysms are commonly “termination type” with the aneurysm forming with a relatively wide neck at the site of the inferred jet of flowing blood dynamics, with main branches nearly perpendicular to the parent vessel, also commonly seen for basilar tip, internal carotid tip, and middle cerebral bifurcations.⁸The Cerecyte Coil Trial (CCT) was a prospective, randomized, controlled study that entered 500 cases comparing endovascular coiling of ruptured and unruptured cerebral aneurysms with either Cerecyte or bare platinum coils that showed no difference between groups.^9,10 There was an expected large subset of AcomA aneurysms within the CCT cohort (n = 124).⁹ Therefore, data from this trial provided a unique opportunity to obtain a large number of AcomA aneurysm cases for determination of A1 dominance in relation to coiling treatment and angiographic outcomes immediately posttreatment and at follow-up. Our goal was to determine the impact of A1 dominance on treatment success, stability, and clinical outcomes of endovascularly coiled AcomA aneurysms.     

Generalized versus Patient-Specific Inflow Boundary Conditions in Computational Fluid Dynamics Simulations of Cerebral Aneurysmal Hemodynamics

BACKGROUND AND PURPOSE:Attempts have been made to associate intracranial aneurysmal hemodynamics with aneurysm growth and rupture status. Hemodynamics in aneurysms is traditionally determined with computational fluid dynamics by using generalized inflow boundary conditions in a parent artery. Recently, patient-specific inflow boundary conditions are being implemented more frequently. Our purpose was to compare intracranial aneurysm hemodynamics based on generalized versus patient-specific inflow boundary conditions.MATERIALS AND METHODS:For 36 patients, geometric models of aneurysms were determined by using 3D rotational angiography. 2D phase-contrast MR imaging velocity measurements of the parent artery were performed. Computational fluid dynamics simulations were performed twice: once by using patient-specific phase-contrast MR imaging velocity profiles and once by using generalized Womersley profiles as inflow boundary conditions. Resulting mean and maximum wall shear stress and oscillatory shear index values were analyzed, and hemodynamic characteristics were qualitatively compared.RESULTS:Quantitative analysis showed statistically significant differences for mean and maximum wall shear stress values between both inflow boundary conditions (P < .001). Qualitative assessment of hemodynamic characteristics showed differences in 21 cases: high wall shear stress location (n = 8), deflection location (n = 3), lobulation wall shear stress (n = 12), and/or vortex and inflow jet stability (n = 9). The latter showed more instability for the generalized inflow boundary conditions in 7 of 9 patients.CONCLUSIONS:Using generalized and patient-specific inflow boundary conditions for computational fluid dynamics results in different wall shear stress magnitudes and hemodynamic characteristics. Generalized inflow boundary conditions result in more vortices and inflow jet instabilities. This study emphasizes the necessity of patient-specific inflow boundary conditions for calculation of hemodynamics in cerebral aneurysms by using computational fluid dynamics techniques.

It has been estimated that the prevalence of intracranial aneurysms in the adult population is between 1% and 5%.¹ Although most aneurysms go undetected, acute rupture resulting in subarachnoid hemorrhage is associated with high morbidity and fatality rates.^2,3 Ruptured aneurysms are treated by coiling or clipping to prevent rebleed. The indication for preventive treatment of unruptured aneurysms is, however, not straightforward.^4,5 The risk of treatment has to be carefully balanced against the risk of rupture. At present, rupture-risk assessment of unruptured intracranial aneurysms and the decision to treat or wait and scan are mainly based on size, location, and growth of the aneurysm.⁶ It is, however, clear that the predictive value of these characteristics is limited.^1,6–8 It is therefore crucial to search for additional and more predictive parameters for aneurysm rupture risk assessment.Aneurysmal hemodynamics, in particular wall shear stress (WSS) and vortex instability, have been proposed as additional risk factors for aneurysm growth and rupture.^9,10 It has been shown that the combination of vortex instability and high or low WSS within the aneurysm is more prevalent in ruptured cases.^11–13In many studies, computational fluid dynamics (CFD) is used to simulate aneurysmal hemodynamics. CFD is traditionally performed by using generalized inflow boundary conditions based on typical flow rates in a healthy adult.^14–27 Recently, several studies have replaced these generalized inflow boundary conditions by patient-specific velocity measurements in the vessels proximal to the aneurysm.^{10,12,28–32} In these studies, either 2D phase-contrast MR imaging (PC-MR imaging) or transcranial Doppler sonography was used to measure the flow. So far, only 3 studies have compared patient-specific with generalized inflow boundary conditions in a total of 14 aneurysms.^28–30 Evidently, the necessity of using patient-specific inflow boundary conditions has not been elucidated to the full extent. In this study, we assessed the effects of patient-specific inflow boundary conditions in a group of 36 patients.     

Dual Stenting Using Low-Profile LEO Baby Stents for the Endovascular Management of Challenging Intracranial Aneurysms

BACKGROUND AND PURPOSE:Endovascular treatment of wide-neck, complex, and distally located cerebral aneurysms is a challenging issue. This study evaluated the safety and efficacy of dual stent placement by using a low-profile stent system (LEO Baby) for the treatment of challenging distal intracranial aneurysms.MATERIALS AND METHODS:We retrospectively reviewed patients in whom at least 1 LEO Baby stent was used in the context of dual stent placement for the treatment of intracranial aneurysms. Patients who were treated with dual stent-assisted coil embolization and telescopic implantation of LEO Baby stents were included in the study. Clinical and angiographic findings, procedural data, and follow-up are reported.RESULTS:Twelve patients were included in this study. Three patients presented with subarachnoid hemorrhage in the subacute-chronic phase, and the remaining patients had unruptured aneurysms. Nine patients were treated by using the dual stent-assisted coiling method. X- (nonintersecting), Y- (intersecting and reversible), T-, and parallel-stent configurations were performed for the dual stent-assisted coiling procedures. Three patients were treated by using telescopic stent placement for a flow diverter–like effect. The procedures were successful in all cases. Technical complications without a significant clinical adverse event developed in 2 patients. The 3- and 6-month control MRAs and DSAs demonstrated complete occlusion of the aneurysms in all patients except 1. All patients had good clinical outcomes on follow-up (mRS ≤1).CONCLUSIONS:The results of this small study showed the feasibility of dual stent placement by using low-profile LEO Baby stents to treat distally located complex intracranial aneurysms.

Coiling of intracranial aneurysms is safe and effective, but endovascular treatment of wide-neck and anatomically complex aneurysms remains challenging.¹ Self-expandable intracranial stents have been used in the past decade to achieve successful and durable coil embolizations of these aneurysms.^2–4 The placement of a stent bridging the ostium of a wide-neck aneurysm creates a scaffold, which prevents the protrusion or herniation of coils into the parent artery and results in denser coil packing. In addition to the mechanical effect, intracranial stents have hemodynamic and biologic effects.^5–8 Stent deployment across the orifice of an aneurysm is thought to redirect blood flow from the sac of the aneurysm toward the distal parent artery and decrease the hemodynamic stress that contributes to thrombosis of the aneurysmal sac.⁹ Furthermore, stent-induced neointimal overgrowth leads to the healing of the neck of the aneurysm.¹⁰ On the basis of these effects, stent monotherapy has been proposed as an alternative strategy for the endovascular treatment of uncoilable and complex intracranial aneurysms.^9–11 The telescopic placement of self-expandable intracranial stents can adequately divert the blood flow, especially for the treatment of blisterlike aneurysms.¹²Recently, low-profile, self-expandable, braided intracranial stents (LEO Baby [Balt, Montmorency, France] and LVIS Jr. [MicroVention, Tustin, California]) have been available for the endovascular treatment of complex and/or distal aneurysms.^13,14 These low-profile intracranial stents can be deployed into arteries with diameters of <3.5 mm and delivered through microcatheters with an internal diameter of 0.0165 inches, which allows easier navigation in small-sized, delicate vessels.A single stent may not suffice for the endovascular treatment of wide-neck and geometrically complex bifurcation aneurysms with involvement of 1 or both side branches. Endovascular treatment of these complex aneurysms often necessitates the implantation of 2 stents (ie, dual stent placement) in various configurations, such as Y-, X-, or parallel configurations.^14–16This retrospective study evaluated the safety and efficacy of dual stent placement by using a low-profile stent system (LEO Baby) for the treatment of challenging intracranial aneurysms.     

Flow Diversion versus Traditional Endovascular Coiling Therapy: Design of the Prospective LARGE Aneurysm Randomized Trial

BACKGROUND AND PURPOSE:The goal of aneurysm treatment is occlusion of an aneurysm without morbidity or mortality. Using well-established, traditional endovascular techniques, this is generally achievable with a high level of safety and efficacy. These techniques involve either constructive treatment of the aneurysm (coils with or without an intravascular stent) or deconstruction (coil occlusion) of the aneurysm and the parent artery. While established as safe and efficacious, the constructive treatment of large and giant aneurysms with coils has typically been associated with relatively lower rates of complete occlusion and higher rates of recurrence. Parent artery deconstruction, though immediately efficacious in achieving complete and durable occlusion, does require occlusion of a major intracranial blood vessel and is associated with risk of stroke.MATERIALS AND METHODS:Flow diversion represents a new technology that can be used to constructively treat large and giant aneurysms. Once excluded successfully, the vessel reconstruction and aneurysm occlusion appears durable. The ability to definitively reconstruct cerebral blood vessels is an attractive approach to these large and giant complex aneurysms and allows the treatment of some aneurysms which were previously not amenable to other therapies. By comparison, conventional coiling techniques have traditionally been used for endovascular treatment of large aneurysms. Large and giant aneurysms that are amenable to either flow diversion or traditional endovascular treatment will be randomized to either therapy with FDA (or appropriate regulatory body) approved devices.RESULTS:The trial is currently enrolling and results of the data are pending the completion of enrollment and follow-up.CONCLUSIONS:This paper details the trial design of the LARGE trial, a blinded, prospective randomized trial of large anterior circulation aneurysms amenable to either traditional endovascular treatments using coils or reconstruction with flow diverters.

Cerebral aneurysms (ie, intracranial aneurysms [IAs]) are a relatively common cerebrovascular abnormality that has been reported to occur in 0.8%–10.0% of the population.^1–4 The risk of IA rupture has been shown to increase with increasing size.^5,6 The most common presentation of IAs is subarachnoid hemorrhage, the annual incidence of which varies by geographic region from 10 to 20 per 100,000 with a case-fatality rate of 51%.^7,8 For these reasons, most physicians recommend treatment for large (>10 mm), intradural IAs.Historically, the treatment of very large and giant aneurysms has focused on deconstructive approaches in which the parent artery bearing the aneurysm is occluded, or complex microsurgical procedures requiring flow arrest with clip reconstruction or entailing bypass strategies to distal-downstream cerebral circulation.^9–11 This requires that a patient has ample collateral channels to compensate for the occlusion of the artery supplying the aneurysm and typically this must be confirmed by a test balloon occlusion.^12,13 This method of aneurysm treatment yields an immediate and durable cure of the lesion treated and has been shown to have an acceptable safety profile with morbidity and mortality rates ranging from 0%–16%. These rates appear to be dependent upon rigorous physiologic assessment of collateral circulation reserve using intraprocedural hypotensive challenges and or postprocedural imaging with CBF assessment using SPECT or other modalities. When parent vessel deconstruction is used for the treatment of symptomatic aneurysms, the presenting clinical symptoms have been reported to resolve in 75% of cases, improve in 10%, and remain unchanged in 15% of cases.⁹ When feasible, deconstructive treatment remains a viable treatment strategy for these lesions.Currently, the most common endovascular treatment approach to IAs has been constructive endosaccular coil embolization. Despite the popularity of coil embolization for the treatment of IAs, incomplete occlusion of the target IA is surprisingly common, approaching 65% in aneurysms larger than 10 mm.^14–16 Several factors are known to predict the likelihood of complete IA occlusion after constructive treatment with coil embolization. The most important factors predicting incomplete occlusion are overall lesion diameter and neck size. Large and giant IAs and those with wide necks are even less likely to have complete occlusion after coil embolization.^16,17 The presence of intraluminal thrombus is also highly associated with repeated incidences of recurrence and retreatment. Other accepted morphologic predictors of incomplete IA occlusion include aneurysm shape and location. Complete or near complete IA occlusion is the goal of endosaccular aneurysm treatment. Several studies have shown that incomplete occlusion of the target IA is a risk factor for subsequent IA regrowth and retreatment and it is believed that incompletely occluded aneurysms retain their risk for rupture and subarachnoid hemorrhage.¹⁸ The evolution of coil technology and the advent of adjunctive devices such as stents and balloons have greatly facilitated the constructive treatment of large and giant, wide-neck IAs. With modern constructive techniques, peri-procedure morbidity rates for the treatment of these challenging aneurysms has declined from 25% to 2%–11%.¹⁹ Moreover, there are some data to suggest that the application of these adjunctive devices, particularly endoluminal stents, may improve the rates of complete aneurysm occlusion and support the durability of treatment.²⁰Endoluminal aneurysm reconstruction using flow diverters represents a new endovascular approach to IA treatment. Emerging clinical data have shown that this approach may yield considerably higher rates of complete aneurysm occlusion in comparison with traditional endosaccular approaches.²¹ The prospective, multicenter, Pipeline for Uncoilable or Failed Aneurysms (PUFS) study that trialed the treatment of large and giant wide-neck carotid aneurysms with the Pipeline embolization device (Covidien, Irvine, California) flow diverter reported complete angiographic occlusion rates approaching 90% at 1-year follow-up.²²The recent PUFS data reported a 15% major neurologic adverse event rate and 44% minor adverse event rate with flow diverters. Particularly of concern are unexplained incidences of catastrophic delayed spontaneous ipsilateral intracranial parenchymal hemorrhage and delayed aneurysmal ruptures that have been reported in up to 5% of cases after flow diversion and have not been typically associated with standard endosaccular coil embolization or parent artery deconstruction.^23–25To date, no study has directly compared the safety and efficacy of flow diverters with conventional endovascular coil-based techniques for the treatment of large and giant, wide-neck IAs that are amenable to either treatment approach. In this article, we describe the design and methods of a large, ongoing randomized clinical trial ({"type":"clinical-trial","attrs":{"text":"NCT01762137","term_id":"NCT01762137"}}NCT01762137) to assess efficacy and safety of traditional endovascular therapy using coils with or without adjunctive devices in a reconstructive or deconstructive manner versus approved flow-diversion technologies in the treatment of large anterior circulation intracranial aneurysms.     

Diffusion-Weighted Imaging–Detected Ischemic Lesions following Endovascular Treatment of Cerebral Aneurysms: A Systematic Review and Meta-Analysis

BACKGROUND AND PURPOSE:Endovascular treatment of intracranial aneurysms is associated with the risk of thromboembolic ischemic complications. Many of these events are asymptomatic and identified only on diffusion-weighted imaging. We performed a systematic review and meta-analysis to study the incidence of DWI positive for thromboembolic events following endovascular treatment of intracranial aneurysms.MATERIALS AND METHODS:A comprehensive literature search identified studies published between 2000 and April 2016 that reported postprocedural DWI findings in patients undergoing endovascular treatment of intracranial aneurysms. The primary outcome was the incidence of DWI positive for thromboembolic events. We examined outcomes by treatment type, sex, and aneurysm characteristics. Meta-analyses were performed by using a random-effects model.RESULTS:Twenty-two studies with 2148 patients and 2268 aneurysms were included. The overall incidence of DWI positive for thromboembolic events following endovascular treatment was 49% (95% CI, 42%–56%). Treatment with flow diversion trended toward a higher rate of DWI positive for lesions than coiling alone (67%; 95% CI, 46%–85%; versus 45%; 95% CI, 33%–56%; P = .07). There was no difference between patients treated with coiling alone and those treated with balloon-assisted (44%; 95% CI, 29%–60%; P = .99) or stent-assisted (43%; 95% CI, 24%–63%; P = .89) coiling. Sex, aneurysm rupture status, location, and size were not associated with the rate of DWI positive for lesions.CONCLUSIONS:One in 2 patients may have infarcts on DWI following endovascular treatment of intracranial aneurysms. There is a trend toward a higher incidence of DWI-positive lesions following treatment with flow diversion compared with coiling. Patient demographics and aneurysm characteristics were not associated with DWI-positive thromboembolic events.

Coil embolization and flow diversion have proved highly efficacious options for the endovascular treatment of intracranial aneurysms. However, both techniques are associated with potential periprocedural complications, including aneurysm rupture, transient ischemic attacks, and ischemic stroke. Small, silent infarcts caused by thromboemboli are often seen on postprocedural diffusion-weighted imaging. While many of these lesions remain ostensibly asymptomatic, the long-term effects of such tiny infarcts remain unclear.^1–3Previous studies have reported that the rate of ischemic lesions on postoperative DWI ranges from 10% to 77% following coil embolization^4–15 and 51% to 63% following therapy with flow diversion.^16–19 However, baseline clinical and angiographic risk factors for postoperative DWI lesions, to our knowledge, have not been fully elucidated previously. We performed a systematic review and meta-analysis for the following: 1) to determine the overall incidence of perioperative infarcts on DWI in patients undergoing endovascular treatment of intracranial aneurysms; and 2) to demonstrate the relationship between treatment type, patient demographics, and aneurysm characteristics with postoperative infarcts on DWI.     

Flow Diversion with Low-Profile Braided Stents for the Treatment of Very Small or Uncoilable Intracranial Aneurysms at or Distal to the Circle of Willis

BACKGROUND AND PURPOSE:The endovascular treatment of aneurysms located at or distal to the circle of Willis and not amenable to coiling remains a challenge. We report our experience with flow-diversion treatment using low-profile braided stents as a stent monotherapy procedure for treating distally located very small or uncoilable aneurysms.MATERIALS AND METHODS:We retrospectively reviewed our data bases to identify patients with aneurysms located at or distal to the circle of Willis who were treated with stent monotherapy using low-profile braided stents. The immediate and follow-up angiographic findings and clinical status of the patients were assessed.RESULTS:Twenty aneurysms in 19 patients were included in the study. The mean size of the aneurysms was 4.7 ± 2.4 mm. Patients were treated via telescopic implantation of 2 stents for 11 aneurysms; single-stent placement was used for the remaining aneurysms. The technical success rate was 95%. We observed a technical complication in 1 case (5.3%) and a late ischemic event in another (5.3%). The final angiographies during a mean follow-up of 14.7 months showed complete aneurysm occlusion in 73.7%. The complete occlusion rate of the aneurysms treated with telescopic stent placement was 81.8%. The modified Rankin scale scores of all patients at the last follow-up were between 0 and 2.CONCLUSIONS:Flow diversion with low-profile braided stents as a stent monotherapy procedure for very small or uncoilable intracranial aneurysms located at or beyond the circle of Willis is a promising, relatively safe, and durable endovascular procedure.

In the past decade, several self-expandable stents dedicated to intracranial use have been introduced to treat wide-neck and complex aneurysms previously not amenable to coiling.^1–4 Stents create a mechanical scaffold, which prevents coil protrusion into the parent artery. In addition to this mechanical scaffolding effect, the implantation of stents also produces hemodynamic and biologic effects in the parent arteries that promote aneurysm occlusion. Stent deployment across the orifice of an aneurysm redirects the blood flow in the parent artery to decrease hemodynamic stress, which facilitates thrombosis in the aneurysmal sac.⁵ Furthermore, stents induce neointimal proliferation in the parent artery, which eventually leads to healing of the aneurysm neck.⁶ The hemodynamic and biologic effects of stents promote the progressive occlusion of partially coiled aneurysms and impede their recanalization.On the basis of the hemodynamic and biologic effects of stents, flow-diversion treatment as a stent monotherapy procedure using conventional stents has been proposed for the endovascular treatment of intracranial aneurysms not amenable to coiling or alternative open surgical procedures.⁷ Flow diversion as a stent monotherapy procedure consists of the implantation of a self-expandable stent or stents across the neck of an aneurysm, without coiling the aneurysm sac. A limited number of previous case series reported the application of stent monotherapy with balloon-expandable or conventional self-expandable stents and focused on the treatment of aneurysms located proximal to the circle of Willis.^7–10Low-profile braided stents have been recently introduced to treat aneurysms located at small-sized, distal parent arteries. Low-profile intracranial stents can be deployed into arteries with diameters between 1.5 and 3.5 mm, and they can be delivered through microcatheters with an internal diameter of 0.0165 inches, which allows easier navigation in small-sized, delicate vessels.¹¹ In this report, we present our experience with flow-diversion treatment as a stent monotherapy procedure for treating very small or uncoilable intracranial aneurysms located at or beyond the circle of Willis using low-profile braided stents. In this retrospective study, we investigated the feasibility, efficacy, and midterm durability of the stent monotherapy procedure with LEO Baby stents (Balt, Montmorency, France).     

Coiling of Large and Giant Aneurysms: Complications and Long-Term Results of 334 Cases

BACKGROUND AND PURPOSE:Large and giant intracranial aneurysms are increasingly treated with endovascular techniques. The goal of this study was to retrospectively analyze the complications and long-term results of coiling in large and giant aneurysms (≥10 mm) and identify predictors of outcome.MATERIALS AND METHODS:A total of 334 large or giant aneurysms (≥10 mm) were coiled in our institution between 2004 and 2011. Medical charts and imaging studies were reviewed to determine baseline characteristics, procedural complications, and clinical/angiographic outcomes. Aneurysm size was 15 mm on average. Two hundred twenty-five aneurysms were treated with conventional coiling; 88, with stent-assisted coiling; 14, with parent vessel occlusion; and 7, with balloon-assisted coiling.RESULTS:Complications occurred in 10.5% of patients, with 1 death (0.3%). Aneurysm location and ruptured aneurysms predicted complications. Angiographic follow-up was available for 84% of patients at 25.4 months on average. Recanalization and retreatment rates were 39% and 33%, respectively. Larger aneurysm size, increasing follow-up time, conventional coiling, and aneurysm location predicted both recurrence and retreatment. The annual rebleeding rate was 1.9%. Larger aneurysm size, increasing follow-up time, and aneurysm location predicted new or recurrent hemorrhage. Favorable outcomes occurred in 92% of patients. Larger aneurysm size, poor Hunt and Hess grades, and new or recurrent hemorrhage predicted poor outcome.CONCLUSIONS:Coiling of large and giant aneurysms has a reasonable safety profile with good clinical outcomes, but aneurysm reopening remains very common. Stent-assisted coiling has lower recurrence, retreatment, and new or recurrent hemorrhage rates with no additional morbidity compared with conventional coiling. Aneurysm size was a major determinant of recanalization, retreatment, new or recurrent hemorrhage, and poor outcome.

Large and giant intracranial aneurysms (≥10 mm) have a poor natural history and usually warrant intervention. A recently published study from Japan reported an annual rupture rate of 4.37% for 10- to 24-mm aneurysms and 33.4% for aneurysms larger than 24 mm.¹ Treatment options for large and giant aneurysms include open surgery or endovascular techniques. Surgical treatment is often challenging and can be associated with significant morbidity.^2,3 Endovascular therapy has emerged as a minimally invasive alternative to open surgery in most neurovascular centers.^4,5 Available endovascular modalities include endosaccular coiling with or without stent/balloon assistance, endovascular parent vessel deconstruction, Onyx HD-500 (ev3, Irvine, California) embolization, and, recently, flow diversion.⁶ Endosaccular coiling is currently the most commonly used treatment technique for large and giant aneurysms, especially in the setting of subarachnoid hemorrhage. Parent vessel occlusion, when tolerated, is also a reliable and durable treatment typically considered in giant aneurysms.⁴Despite increasing and widespread use of endovascular techniques, little is known about the morbidity rates, rehemorrhage rates, and long-term angiographic results of coiling in large and giant aneurysms. In addition, predictors of treatment outcome have not been identified. In this study, we analyzed the complications and long-term results of coiling in the largest series of large and giant aneurysms (≥10 mm) to date. In addition, a multivariate logistic regression analysis was conducted to identify predictors of complications, recurrence, retreatment, new or recurrent hemorrhage, and clinical outcome.     

Endovascular Coiling of Wide-Neck and Wide-Neck Bifurcation Aneurysms: A Systematic Review and Meta-Analysis

BACKGROUND AND PURPOSE:We present the results of a systematic review and meta-analysis examining outcomes of endovascular coiling of wide-neck and wide-neck bifurcation aneurysms with and without stent assistance. The aim of our study was to assess angiographic and clinical outcomes.MATERIALS AND METHODS:We performed a comprehensive literature search for all articles on the endovascular coiling of wide-neck and wide-neck bifurcation aneurysms. Studies meeting our inclusion criteria and abstracted data were selected by 2 independent reviewers. Primary outcomes were >6-month complete or near-complete angiographic occlusion, aneurysm recanalization, and aneurysm retreatment. Secondary outcomes included initial complete or near-complete occlusion, long-term good neurologic outcome, procedure-related morbidity, and procedure-related mortality. Data were analyzed by using random-effects meta-analysis.RESULTS:In total, 38 studies including 2446 patients with 2556 aneurysms were included. For all wide-neck aneurysms, immediate complete or near-complete occlusion rate was 57.4% (95% CI, 48.1%–66.8%). Follow-up near-complete occlusion rate was 74.5% (95% CI, 68.0%–81.0%). Recanalization and retreatment rates were 9.4% (95% CI, 7.1%–11.7%) and 5.8% (95% CI, 4.1%–7.5%), respectively. Long-term good neurologic outcome was 91.4% (95% CI, 88.5%–94.2%). For wide-neck bifurcation aneurysms, initial complete or near-complete occlusion rate was 60.0% (95% CI, 42.7%–77.3%), long-term complete or near-complete occlusion rate was 71.9% (95% CI, 52.6%–91.1%), and the recanalization and retreatment rates were 9.8% (95% CI, 7.1%–12.5%) and 5.2% (95% CI, 1.9%–8.4%), respectively.CONCLUSIONS:Our study of angiographic and clinical outcomes for patients with wide-neck aneurysms demonstrates that endovascular coiling with or without stent-assisted coiling is safe, with low rates of perioperative morbidity and mortality. Initial and long-term angiographic outcomes were generally satisfactory, but not ideal. These data provide some baseline comparisons against which emergent technologies can be assessed.

With the advent of stent-assisted and balloon-assisted coiling, wide-neck and wide-neck bifurcation intracranial aneurysms are increasingly treated with endovascular techniques to prevent hemorrhage or recurrent bleeding. Both stent-assisted and balloon-assisted coiling have been shown to be safe and effective in the treatment of these aneurysms by allowing for increased packing density and lower rates of parent artery occlusion compared with conventional coiling alone.^1–5 Even in the era of endoluminal and intrasaccular flow diverters, many wide-neck and wide-neck bifurcation aneurysms will continue to be treated with conventional coiling, particularly with stent assistance.^6–8We present the results of a systematic review and meta-analysis examining outcomes of endovascular coiling of wide-neck and wide-neck bifurcation aneurysms with and without stent-assisted coiling. The aim of our study was to assess both angiographic and clinical outcomes in order to provide overall data against which current and future emergent techniques can be compared.     

Endovascular Treatment of Wide-Neck Anterior Communicating Artery Aneurysms Using WEB-DL and WEB-SL: Short-Term Results in a Multicenter Study

BACKGROUND AND PURPOSE:Endovascular treatment of wide-neck anterior communicating artery aneurysms can often be challenging. The Woven EndoBridge (WEB) device is a recently developed intrasaccular flow disrupter dedicated to endovascular treatment of intracranial aneurysms. The aim of this study was to investigate the feasibility, safety, and efficacy of the WEB Dual-Layer and WEB Single-Layer devices for the treatment of wide-neck anterior communicating artery aneurysms.MATERIALS AND METHODS:Patients with anterior communicating artery aneurysms treated with the WEB device between June 2013 and March 2014 in 5 French centers were analyzed. Procedural success, technical complications, clinical outcome at 1 month, and immediate and 3- to 6-month angiographic follow-up results were analyzed.RESULTS:Ten patients with unruptured anterior communicating artery aneurysms with a mean neck diameter of 5.4 mm were treated with the WEB. Treatment failed in 3 of the 10 aneurysms without further clinical complications. One patient developed a procedural thromboembolic event, and the other 6 had normal neurologic examination findings at 1-month follow-up. Immediate anatomic outcome evaluation showed adequate occlusion (total occlusion or neck remnant) in 6 of 7 patients. Angiographic control was obtained in all patients, including 6 adequate aneurysm occlusions (3 complete occlusions and 3 neck remnants) at short-term follow-up.CONCLUSIONS:In our small series, treatment of wide-neck anterior communicating artery aneurysms with the WEB device was feasible and safe. However, patient selection based on the aneurysm and initial angiographic findings in the parent artery is important due to the limitations of the WEB device navigation.

Coiling of intracranial aneurysms is now a well-established endovascular treatment option.^1,2 Nevertheless, in cases of wide-neck aneurysms, coiling alone has often been proved unsuitable. Balloon-assisted and stent-assisted coiling may be therapeutic options.^3–5 However, low rates of initial angiographic occlusion and high rates of recurrence are reported in such situations.^5–7 In addition, bifurcation aneurysms often require an X- or Y-configuration double-stent treatment technique that carries a higher rate of procedural complications^8–13 in addition to the complications linked to the mandatory use of dual antiplatelet therapy.^11–13The Woven EndoBridge (WEB) aneurysm embolization system (Sequent Medical, Aliso Viejo, California) is a recently developed intrasaccular flow disruptor dedicated to intracranial wide-neck aneurysm management; to date, WEB Dual-Layer (WEB-DL) feasibility, safety, and short-term angiographic findings have only been reported in a few studies, mostly in aneurysms of the middle cerebral artery, while its feasibility and results in treatment of anterior communicating artery aneurysms are not well-known.^14–18 The characteristics of the WEB device combining a large-diameter microcatheter and a relatively stiff device may hamper its placement in this location.The goal of this study was to analyze the feasibility, safety, and efficacy of WEB-DL and WEB Single-Layer (WEB-SL) flow disruptors for the treatment of wide-neck anterior communicating artery aneurysms.     

Flow Diversion in Ruptured Intracranial Aneurysms: A Meta-Analysis

BACKGROUND:Flow diversion is now an established technique to treat unruptured intracranial aneurysms not readily amenable to endovascular coil embolization or open microsurgical occlusion. The role of flow-diverting devices in treating ruptured aneurysms is less clear.PURPOSE:To estimate rates of angiographic occlusion and good clinical outcome in patients with ruptured intracranial aneurysms treated with flow-diverting devices.DATA SOURCES:Systematic review of Ovid MEDLINE, PubMed, Cochrane databases, and EMBASE from inception to December 2015 for articles that included ruptured aneurysms treated with flow diversion.STUDY SELECTION:One hundred seventy-two records were screened, of which 20 articles contained sufficient patient and outcome data for inclusion.DATA ANALYSIS:Clinical and radiologic characteristics, procedural details, and outcomes were extracted from these reports. Aggregated occlusion rates and clinical outcomes were analyzed by using the Fisher exact test (statistical significance, α = .05).DATA SYNTHESIS:Complete occlusion of the aneurysm was achieved in 90% of patients, and favorable clinical outcome was attained in 81%. Aneurysm size greater than 7 mm was associated with less favorable clinical outcomes (P = .027). Aneurysm size greater than 2 cm was associated with a greater risk of rerupture after treatment (P < .001).LIMITATIONS:Observational studies and case reports may be affected by reporting bias.CONCLUSIONS:Although not recommended as a first-line treatment, the use of flow diverters to treat ruptured intracranial aneurysms may allow high rates of angiographic occlusion and good clinical outcome in carefully selected patients. Aneurysm size contributes to treatment risk because the rerupture rate following treatment is higher for aneurysms larger than 2 cm.

Endovascular treatment of intracranial aneurysms with detachable coils was first described in 1991¹ and has since become an established method of aneurysm treatment. The International Study of Unruptured Intracranial Aneurysms² and Analysis of Treatment by Endovascular Approach of Nonruptured Aneurysms (ATENA)³ demonstrated the effectiveness and relative safety of endovascular coiling for unruptured aneurysms. Similarly, the International Subarachnoid Aneurysm Trial (ISAT), the Barrow Ruptured Aneurysm Trial, and other trials^4–7 have demonstrated the effectiveness and relative safety of endovascular coiling in ruptured aneurysms.In recent years, flow diverters (FDs) have emerged as a new endovascular treatment option for intracranial aneurysms. FDs are a reconstructive treatment in which altered flow within an aneurysm induces gradual remodeling and eventual thrombosis of the aneurysm. Several studies have demonstrated good safety and efficacy of FDs for the treatment of unruptured intracranial aneurysms,^8–17 though the safe use of these devices requires the use of dual antiplatelet therapy.^18–20Understandably, the need for antiplatelet medications and the delayed nature of aneurysm thrombosis have tempered enthusiasm for using FDs for ruptured aneurysms. Nevertheless, several reports have described the use of FDs to treat recently ruptured aneurysms, particularly those that are difficult to treat by other endovascular or open microsurgical techniques.In this meta-analysis, we review the outcomes associated with the use of FDs for the treatment of ruptured intracranial aneurysms. Specifically, we review aneurysm characteristics and endovascular treatment strategies in relation to the rates of angiographic occlusion and good clinical outcome, with the overall goal of guiding FD use in ruptured aneurysms when other treatment options are not viable.     

The Success of Flow Diversion in Large and Giant Sidewall Aneurysms May Depend on the Size of the Defect in the Parent Artery

BACKGROUND AND PURPOSE:Flow diverters are designed to occlude aneurysms while preserving flow to jailed arterial branches. We postulated that treatment success depended on the size of the aneurysm ostium or defect in the parent artery.MATERIALS AND METHODS:Flow diverter expansion and deformation were studied in silicone tubes with wall apertures of various sizes. Large and giant canine sidewall aneurysms, featuring a branch located immediately opposite the aneurysm, and a smaller 6- to 8-mm (group A, n = 6) or a larger 10- to 16-mm (group B, n = 6) ostium were created to study the effects of ostium size on aneurysm or branch occlusion by flow diverters. Angiographic results after deployment and at 3 months were scored by using an ordinal scale. The amount of neointima formation on the segment of the device overlying the aneurysm or the branch ostia was determined by specimen photography.RESULTS:The fusiform deformation of flow diverters was maximal with larger defects in silicone tubes. At 3 months, group B aneurysms showed worse angiographic results than group A aneurysms, with larger residual aneurysm volumes (P = .002). Neointimal coverage of the aneurysm ostia was more complete in group A compared with group B (P = .002).CONCLUSIONS:The effects of flow diversion may vary with the size of the aneurysm ostium.

Flow diverters are increasingly used to treat large, giant, and, more recently, bifurcation aneurysms.^1–8 Successful treatment of the aneurysm with a flow diverter (FD) requires protecting the patient from rupture by reducing aneurysm flow, promoting thrombosis, and perhaps even repairing the defect in the parent artery, without occluding arterial branches covered by the device. The optimal device porosity and pore density to successfully occlude aneurysms while sparing jailed branches remain unknown and most likely differ from case to case. While FDs have been introduced in the market as if 1 porosity would be appropriate for all cases, previous studies, in a modular carotid aneurysm model, have shown that some FDs are capable of occluding straight sidewall aneurysms but fail when implanted across curved sidewall, bifurcation, or giant fusiform aneurysms with multiple side branches.^9–12The capacity for a particular FD to occlude an aneurysm may correlate with the size of the defect in the parent vessel or ostium of the aneurysm. In the present investigation, we explored how flow diverters become deformed in silicone tubes in which wall defects of variable sizes have been created. Deformation of the device may change its capacity to divert flow. In vivo, we used a straight sidewall aneurysm model, a configuration previously shown to be favorable to flow diversion,⁹ but modified to obtain large or giant aneurysms with variable-sized ostia (small or wide), to study how the size of the defect of the parent artery could influence device expansion, deformation, shortening, and angulation and how it could affect the efficacy of aneurysm occlusion at 3 months.