LEO stent monotherapy for the endovascular reconstruction of fusiform aneurysms of the middle cerebral artery

Flow diversion effect of the leo braided stent for aneurysms in the posterior and distal anterior circulations: A multicenter cohort study

Background and purpose

The treatment of aneurysms located in the posterior and distal anterior circulations remains a challenge. Leo stents with a flow diversion (FD) effect may be a potential option, which needs to be clearly studied.

Methods

From January 2016 to October 2021, 133 patients with 145 aneurysms in the posterior and distal anterior circulations, treated with Leo stents, were retrospectively analyzed in three neurosurgical centers. Data on demographic information, aneurysm characteristics, procedural outcomes, postoperative course, and aneurysm occlusion were retrospectively analyzed.

Results

After immediate surgery, 90 aneurysms (60.1%) were in complete occlusion [Raymond-Ray Occlusion Class (RROC) 1 and O'Kelly Marotta (OKM) grade D], 29 aneurysms (20%) in good occlusion (RROC 2 and OKM grade C), 17.9% in incomplete occlusion (RROC 3a or OKM grade B), and no aneurysms in invalid occlusion (RROC 3b and OKM grade A). A total of 112 patients with 117 aneurysms received angiographic follow-up (mean 11.4 months), and the degree of occlusion showed a significant improvement (Z = 3.900, p < 0.001). The complete occlusion rate increased to 84.6% (99/117), while good and incomplete occlusion decreased to 6.8% (8/117) and 8.6% (10/117), respectively. A total of 14 cases (10.5%) presented narrowing of the parent artery, and nine cases (6.8%) had injured side branches. Cerebral hemorrhage occurred in four patients (3.0%), and symptomatic ischemic infarction occurred in six patients (4.5%). The final permanent morbidity (mCS ≥3) and mortality were 2.8% (3/133) and 0.8% (1/133), respectively. For 82 aneurysms treated by stent-assisted with coiling (SAC), large-sized, ruptured aneurysms (χ² = 7.767, p = 0.005) occurred. For 63 aneurysms treated by LEO stent monotherapy (LSM), multiple aneurysms, fusiform aneurysms (χ² = 18.958, p < 0.01), and/or small-sized aneurysms (Z = −2.692, p = 0.007) occurred.

Conclusions

Leo stents are safe and effective for aneurysms located in the posterior and distal anterior circulations. The overall degree of occlusion improved during a follow-up because of the FD effect of Leo stents. Aneurysms in these areas should be treated with personalized measures.

Characteristics and Clinical Course of Fusiform Middle Cerebral Artery Aneurysms According to Location, Size, and Configuration

OBJECTIVE

To analyze the angiographic features and clinical course, including treatment outcomes and the natural course, of fusiform middle cerebral artery aneurysms (FMCAAs) according to their location, size, and configuration.

METHODS

We reviewed the literature on adult cases of FMCAAs published from 1980 to 2018; from 25 papers, 112 FMCAA cases, for which the location, size, and configuration could be identified, were included in this study. Additionally, 33 FMCAA cases in our hospital were included, from which 16 were assigned to the observation group. Thus, a total of 145 adult FMCAA cases were included. We classified the FMCAAs according to their location (l-type 1, beginning from prebifurcation; l-type 2, beginning from bifurcation; l-type 3, beginning from postbifurcation), size (small, <10 mm; large, ≥10 mm; giant, ≥25 mm), and configuration (c-type 1, classic dissecting aneurysm; c-type 2, segmental ectasia; c-type 3, dolichoectatic dissecting aneurysm).

RESULTS

The c-type 3 was more commonly diagnosed with ischemic symptoms (31.8%) than hemorrhage (13.6%), while 40.9% were found accidentally. In contrast, c-type 2 was more commonly diagnosed with hemorrhagic symptoms (14.9%) than ischemic symptoms (10.6%), and 72.3% were accidentally discovered. According to location, ischemic symptoms and hemorrhage were the most frequent symptoms in l-type 1 (28.6%) and l-type 3 (34.6%), respectively. Most of l-type 2 FMCAAs were found incidentally (68.4%). Based on the size of FMCAAs, only 11.1% of small aneurysms were found to be hemorrhagic, while 18.9% and 26.0% of large and giant aneurysms were hemorrhagic, respectively. Although four aneurysms of the 16 FMCAAs in the observation group increased in size and one aneurysm decreased in size during the observation period, no rupture was seen in any case and there were no significant predictors of aneurysm enlargement. Of 104 FMCAAs treated, 14 cases (13.5%) were aggravated than before surgery and all the aggravated cases were l-type 1.

CONCLUSION

While ischemic symptoms occurred more frequently in l-type 1 and c-type 3, hemorrhagic rather than ischemic symptoms occurred more frequently in l-type 3 and c-type 2. In case of l-type 1 FMCAAs, more caution is required in determining the treatment due to the relatively high complication rate.

Endovascular coiling of proximal middle cerebral artery aneurysms: is it safe and durable?

BACKGROUND

Proximal middle cerebral artery (M1 segment) aneurysms are relatively deeply located in neighboring lenticulostriate arteries, which make them unsuitable for microsurgery. We aimed to investigate the clinical and radiological outcomes of endovascular coiling of M1 segment aneurysms.

METHODS

Between January 2003 and December 2014, we retrospectively reviewed the medical records of 52 patients (52 aneurysms) from four institutions who underwent endovascular coiling of M1 segment aneurysms. Patients who underwent clinical and radiologic follow-up for more than a year after the procedure were evaluated.

RESULTS

The aneurysms were located in the early frontal branch, early temporal branch, and lenticulostriate artery in 28, 15, and nine patients, respectively. Endovascular coiling was achieved in 51 cases and failed in one case. Of these 51 cases, 46 (90.2%) and five (9.8%) were non-ruptured and ruptured aneurysms, respectively. Initial angiographic results revealed complete occlusion in 26 (51.0%), residual neck in 16 (31.4%), and residual sac in nine (17.6%) cases. One failed case had a symptomatic procedural complication of thromboembolism. However, there was no permanent morbidity or mortality. Two major recanalization cases (3.9%) were retreated by endovascular coiling. On multivariable logistic regression analysis, aneurysmal recurrence was significantly related to aneurysm height (OR, 1.887; 95% CI, 1.107 to 3.217; p = 0.020), width (OR, 1.836; CI, 1.127 to 2.992; p = 0.015), and neck (OR, 4.017; CI, 1.220 to 13.232, p = 0.022).

CONCLUSION

Endovascular coiling of M1 segment aneurysms appeared to be a feasible treatment option with a relatively low-retreatment rate. Aneurysm size was statistically significantly associated with recurrence.

Surgical Treatment of Large or Giant Fusiform Middle Cerebral Artery Aneurysms: A Case Series

BACKGROUND

Management of large or giant fusiform middle cerebral artery (MCA) aneurysms represents a significant challenge.

OBJECTIVE

To describe the authors' experience in the treatment of large or giant fusiform MCA aneurysm by using various surgical techniques.

METHODS

We retrospectively reviewed a database of aneurysms treated at our division between 2015 and 2017.

RESULTS

Overall, 20 patients (11 males, 9 females) were identified, with a mean age of 40.7 years (range, 13-65 years; median, 43 years). Six patients (30%) had ruptured aneurysms and 14 (70%) had unruptured aneurysms. The mean aneurysm size was 19 mm (range, 10-35 mm). The aneurysms involved the prebifurcation in 5 cases, bifurcation in 4 cases, and postbifurcation in 11 cases. The aneurysms were treated by clip reconstruction (n = 5), clip wrapping (n = 1), proximal occlusion or trapping (n = 4), and bypass revascularization (n = 10). Bypasses included 7 low-flow superficial temporal artery-MCA bypasses, 2 high-flow extracranial-intracranial bypasses, and 1 intracranial-intracranial bypass (reanastomosis). Bypass patency was 90%. Nineteen aneurysms (95%) were completely obliterated, and no rehemorrhage occurred during follow-up. There was no procedural-related mortality. Clinical outcomes were good (modified Rankin Scale score ≤2) in 18 of 20 patients (90%) at the last follow-up.

CONCLUSIONS

Surgical treatment strategy for large or giant fusiform MCA aneurysms should be determined on an individual basis, based on aneurysm morphology, location, size, and clinical status. Favorable outcomes can be achieved by various surgical techniques, including clip reconstruction, wrap clipping, aneurysm trapping, aneurysm excision followed by reanastomosis, and partial trapping with bypass revascularization.

Long-term follow-up of aneurysms treated electively with woven stent-assisted coiling

Background

Preliminary short-term results for stent-assisted coil embolization (SACE) using woven/braided stents have been promising. However, evidence supporting mid- to long-term efficacy and durability is lacking.

Objective

To report the long-term results for the durability of elective intracranial aneurysms treated with woven stents.

Materials and methods

Between May 2012 and May 2015, 98 consecutive patients with 103 aneurysms underwent elective woven SACE across three Australian neurovascular centres. All patients had immediate, 6- and 18-month clinical and radiological follow-up. Radiological assessment was performed with modified Raymond–Roy occlusion scores based on angiography results, while clinical assessment was based on the modified Rankin Scale.

Results

Six-month follow-up was available in 100 aneurysms, and an 18-month follow-up in 97 aneurysms. Total occlusion rates of 82% were achieved at inception, 82% at 6 months, and 90% at 18 months. Satisfactory occlusion with small neck remnants was present in 17% at inception, 16% at 6 months, and 9% at 18 months. Good neurological outcomes were achieved in 95% at 18 months. Intraprocedural thromboembolic events were recorded in 3% and delayed events in 1% (all in patients taking clopidogrel). Aneurysm recurrence occurred in one patient (1%). Technical complications occurred in 5%. The total complication rate was 10%.

Conclusions

Woven SACE is safe, efficacious, and durable at long-term 18-month follow-up, with very low recurrence and re-treatment rates. Preliminary results appear better than those for traditional laser-cut stents.

Stent-Assisted Coiling of Ruptured and Incidental Aneurysms of the Intracranial Circulation Using Moderately Flow-Redirecting, Braided Leo Stents-Initial Experience in 39 Patients

Background

Flow diversion (FD)—a young technique using stents with highly increased surface coverage—was introduced to treat complex aneurysms without intra-aneurysmal material placement and has amended the spectrum of endovascular techniques such as stent-assisted coil occlusion considerably. However, ischemic complications, a common side effect in FD, occur more frequently compared with the conventional endovascular approaches and certainly limit the indication of this technique. Our study aimed to investigate the feasibility and efficacy of stent-assisted coiling using low profile self-expandable stents, which exhibit only moderate flow-redirecting properties and therefore represent a combination of hemodynamic endovascular and occlusive endosaccular therapy.

Materials and methods

39 Patients were included in our retrospective study. Occlusion rates were assessed 6 months after the procedure in a total of 27 cases using the Raymond scale.

Results

Complete occlusion (Raymond I) was achieved in 24/27 aneurysms. Small neck remnants (Raymond II) were evident in 3/27 aneurysms. There were no cases with sac remnant or complete persistence of aneurysmal filling (Raymond III and IV).

Conclusion

Our study demonstrates interventional treatment of intracranial aneurysms using flow-redirecting stent-assisted coiling to be technically feasible and highly effective in aneurysmal occlusion. We believe that this approach is outstanding in the prevention of long-term aneurysmal reperfusion and exhibits a more acceptable risk profile than highly efficient FD techniques.

Endovascular treatment of wide-neck intracranial bifurcation aneurysms with 'Y'-configuration, double Neuroform® stents-assisted coiling technique: Experience in a single center

Background Intracranial wide-neck aneurysms at the arterial bifurcations, especially in the aneurysms where the bifurcating branches emanate directly from the base of the aneurysm, have been particularly difficult on which to perform endovascular treatment. The 'Y'-configuration, double stent-assisted coil embolization is an option for the treatment of these difficult aneurysms, allowing the closure of the aneurysm, preserving the parent arteries. Material and methods In a nine-year period, 546 intracranial aneurysms in 493 patients were treated at our center by endovascular approach. We have reviewed the medical records and arteriographies from November 2007 to January 2017 of 45 patients who were treated using 'Y'-configuration double Neuroform® stent-assisted coil embolization. Results All patients were successfully treated. The location of the aneurysms were: middle cerebral artery (MCA) 20 (44.4%), anterior communicating artery (AComA) 17 (37.7%), basilar four (8.9%), internal carotid artery (ICA) bifurcation three (6.6%) and posterior communicating artery (PComA) one (2.2%). The mRS at hospital discharge was: mRS 0: 42 (93.3%), mRS 1: 1 (2.2%), mRS 2: 1 (2.2%) and mRS 5: 1 (2.2%). The Modified Raymond-Roy Occlusion Classification, in the control at six months, was: Class I: 41 (91.1%), Class II: 2 (4.4%), Class IIIa: 1 (2.2%) and Class IIIb: 1 (2.2%). Forty-four (97.8%) patients had a good outcome (mRS < 2) at six months. One (2.2%) patient had a poor outcome (mRS > 2) at six months that was due to sequelae of SAH. There was no mortality at six months. Conclusions This technique is safe and effective for the endovascular treatment of difficult wide-neck bifurcation aneurysms, allowing the stable closure of the aneurysm, preserving the parent arteries.

LEO Baby Stent Use following Balloon-Assisted Coiling: Single- and Dual-Stent Technique--Immediate and Midterm Results of 29 Consecutive Patients

BACKGROUND AND PURPOSE

We report our preliminary results in terms of safety and efficacy in using the low-profile LEO Baby stent for the treatment of large-neck and complex intracranial aneurysms with balloon-then-stent-assisted coiling and single- or dual-stent-assisted coiling.

MATERIALS AND METHODS

Clinical and radiologic data of all consecutive patients treated at our institution from September 2012 to October 2013 for an intracranial aneurysm by using a LEO Baby stent were retrospectively analyzed. Immediate and midterm clinical and anatomic follow-up of each patient is reported.

RESULTS

Twenty-nine patients with 29 aneurysms were treated with LEO Baby stents at our institution. The mean age of patients was 48 years; 20 patients were women (71%). One patient was treated in the acute phase of a subarachnoid hemorrhage. In 8 procedures, a double-lumen-catheter balloon was used for balloon-then-stent-assisted coiling. In 3 cases, a LEO Baby stent was used in a Y-, T-, and telescopic dual-stent configuration. In 18 cases, a single LEO Baby stent was used. In 2 cases, technical failure to deploy the stent resulted in acute parent artery thrombosis. In 3 further cases, thromboembolic complications occurred intraoperatively. MR imaging and angiographic midterm follow-up showed complete aneurysm occlusion for 96% of the followed patients (27/29). Clinical outcome was favorable for all patients followed up.

CONCLUSIONS

Results obtained in our study by using the LEO Baby stent for balloon-then-stent and single- or dual-stent-assisted coiling of complex and distally located intracranial aneurysms are encouraging. Incomplete or inadequate opening of the device is a potential cause of laminar blood flow alteration and thrombus formation.

Balloons and stents in the endovascular treatment of cerebral aneurysms: vascular anatomy remodeled

Wide-neck intracranial aneurysms were originally thought to be either untreatable or very challenging to treat by endovascular means because of the risk of coil protrusion into the parent vessel. The introduction of the balloon remodeling technique (BRT) and later stents specifically designed for intracranial use has progressively allowed these lesions to be endovascularly treated. BRT and stent-assisted coiling technique (SACT) were first designed to treat sidewall aneurysms but, with gained experience and further technical refinement, bifurcation complex-shaped wide-neck aneurysms have been treated by coiling enhanced by BRT and SACT. In this article, we will review and describe the inherent benefits and drawbacks of BRT as well as SACT.

Endovascular treatment of middle cerebral artery aneurysms with flow modification with the use of the pipeline embolization device

BACKGROUND AND PURPOSE

The Pipeline Embolization Device was reported to be safe and effective in the treatment of sidewall aneurysms, preserving the patency of the vessels covered by the construct. However, to date, the safety and efficacy of this device in treating bifurcation aneurysms remains unknown. We report our preliminary experience with the use of the Pipeline Embolization Device in the management of MCA aneurysms located at the bifurcations, including mid- and long-term follow-up data.

MATERIALS AND METHODS

Wide-neck MCA aneurysms, which give rise to a bifurcating or distal branch in which other endovascular techniques are thought to be unfeasible or more risky, were included. Data including demographics, aneurysm features, antiplatelet therapy, complications, and angiographic follow-up results for up to 30 months were recorded.

RESULTS

Twenty-five aneurysms located at the MCA bifurcation (n = 21) or distal (n = 4) were treated. Of these, 22 were small and 3 were large. A single device was used in all but 2. No deaths occurred in the series. All patients had at least 1 control angiographic study, 21 of which were DSA (3-30 months), which showed that 12 of the rising branches were patent whereas 6 were filling in reduced caliber and 3 were occluded asymptomatically. According to the last angiographic follow-up, complete occlusion was revealed in 21 of 25 aneurysms (84%).

CONCLUSIONS

The Pipeline Embolization Device provides a safe and effective treatment alternative for wide-neck MCA aneurysms that give rise to a bifurcating or distal branch when other endovascular techniques are thought to be unfeasible or more risky.

Comparison Among Different High Porosity Stent Configurations: Hemodynamic Effects of Treatment in a Large Cerebral Aneurysm

Whether treated surgically or with endovascular techniques, large and giant cerebral aneurysms are particularly difficult to treat. Nevertheless, high porosity stents can be used to accomplish stent-assisted coiling and even standalone stent-based treatments that have been shown to improve the occlusion of such aneurysms. Further, stent assisted coiling can reduce the incidence of complications that sometimes result from embolic coiling (e.g., neck remnants and thromboembolism). However, in treating cerebral aneurysms at bifurcation termini, it remains unclear which configuration of high porosity stents will result in the most advantageous hemodynamic environment. The goal of this study was to compare how three different stent configurations affected fluid dynamics in a large patient-specific aneurysm model. Three common stent configurations were deployed into the model: a half-Y, a full-Y, and a crossbar configuration. Particle image velocimetry was used to examine post-treatment flow patterns and quantify root-mean-squared velocity magnitude (VRMS) within the aneurysmal sac. While each configuration did reduce VRMS within the aneurysm, the full-Y configuration resulted in the greatest reduction across all flow conditions (an average of 56% with respect to the untreated case). The experimental results agreed well with clinical follow up after treatment with the full-Y configuration; there was evidence of thrombosis within the sac from the stents alone before coil embolization was performed. A computational simulation of the full-Y configuration aligned well with the experimental and in vivo findings, indicating potential for clinically useful prediction of post-treatment hemodynamics. This study found that applying different stent configurations resulted in considerably different fluid dynamics in an anatomically accurate aneurysm model and that the full-Y configuration performed best. The study indicates that knowledge of how stent configurations will affect post-treatment hemodynamics could be important in interventional planning and demonstrates the capability for such planning based on novel computational tools.

Advances in Endovascular Approaches to Cerebral Aneurysms

Recent advancements in all phases of endovascular aneurysm treatment, including medical therapy, diagnostics, devices, and implants, abound. Advancements in endovascular technologies and techniques have enabled treatment of a wide variety of intracranial aneurysms. In this article, technical advances in endovascular treatment of cerebral aneurysms are discussed, with an effort to incorporate a clinically relevant perspective. Advancements in diagnostic tools, medical therapy, and implants are reviewed and discussed.

Bypass surgery for complex middle cerebral artery aneurysms: impact of the exact location in the MCA tree

Object

The object of this study was to describe the authors' institutional experience in the treatment of complex middle cerebral artery (MCA) aneurysms necessitating bypass and vessel sacrifice.

Methods

Cases in which patients with MCA aneurysms were treated with a combination of bypass and parent artery sacrifice were reviewed retrospectively.

Results

The authors identified 24 patients (mean age 46 years) who were treated with bypass and parent artery sacrifice. The aneurysms were located in the M1 segment in 7 patients, MCA bifurcation in 8, and more distally in 9. The mean aneurysm diameter was 30 mm (range 7–60 mm, median 26 mm). There were 8 saccular and 16 fusiform aneurysms.

Twenty-one extracranial-intracranial and 4 intracranial-intracranial bypasses were performed. Partial or total trapping (only) of the parent artery was performed in 17 cases, trapping with resection of aneurysm in 3, and aneurysm clipping with sacrifice of an M2 branch in 4.

The mean follow-up period was 27 months. The aneurysm obliteration rate was 100%. No recanalization of the aneurysms was detected during follow-up.

There was 1 perioperative death (4% mortality rate) and 6 cerebrovascular accidents, causing permanent morbidity in 5 patients. The median modified Rankin Scale score of patients with an M1 aneurysm increased from 0 preoperatively to 2 at latest follow-up, while the score was unchanged in other patients. Most of the permanent deficits were associated with M1 aneurysms. Twenty-one patients (88%) had good outcome as defined by a Glasgow Outcome Scale score of 4 or 5.

Conclusions

Bypass in combination with parent vessel occlusion is a useful technique with acceptable frequencies of morbidity and mortality for complex MCA aneurysms when conventional surgical or endovascular techniques are not feasible. The location of the aneurysm should be considered when planning the type of bypass and the site of vessel occlusion. Flow alteration by partial trapping may be preferable to total trapping for the M1 aneurysms.

Flow diverter effect on cerebral aneurysm hemodynamics: an in vitro comparison of telescoping stents and the Pipeline

INTRODUCTION

Flow diverting devices and stents can be used to treat cerebral aneurysms too difficult to treat with coiling or craniotomy and clipping. However, the hemodynamic effects of these devices have not been studied in depth. The objective of this study was to quantify and understand the fluid dynamic changes that occur within bifurcating aneurysms when treated with different devices and configurations.

METHODS

Two physical models of bifurcating cerebral aneurysms were constructed: an idealized model and a patient-specific model. The models were treated with four device configurations: a single low-porosity Pipeline embolization device (PED) and one, two, and three high-porosity Enterprise stents deployed in a telescoping fashion. Particle image velocimetry was used to measure the fluid dynamics within the aneurysms; pressure was measured within the patient-specific model.

RESULTS

The PED resulted in the greatest reductions in fluid dynamic activity within the aneurysm for both models. However, a configuration of three telescoping stents reduced the fluid dynamic activity within the aneurysm similarly to the PED treatment. Pressure within the patient-specific aneurysm did not show significant changes among the treatment configurations; however, the pressure difference across the untreated vessel side of the model was greatest with the PED.

CONCLUSION

Treatment with stents and a flow diverter led to reductions in aneurysmal fluid dynamic activity for both idealized and patient-specific models. While the PED resulted in the greatest flow reductions, telescoping high-porosity stents performed similarly and may represent a viable treatment alternative in situations where the use of a PED is not an option.

Simple coiling using single or multiple catheters without balloons or stents in middle cerebral artery bifurcation aneurysms

Introduction

We evaluated the outcomes of middle cerebral artery bifurcation (MCAB) aneurysms treated with simple coiling using single or multiple catheters without stents or balloons.

Methods

This study included 100 patients with 103 MCAB aneurysms who underwent a simple coiling procedure without the adjuvant use of stents or balloons. The angiographic clinical outcomes and recurrence of these aneurysms were evaluated.

Results

Of the 103 aneurysms, 102 (99.0 %) aneurysms were successfully treated with simple coiling. One patient died from the consequences of a procedural aneurysm rupture. The treatment-associated permanent morbidity and mortality rates were 0 and 1.0 %, respectively. Post-coiling angiograms showed 28 complete occlusions (27.2 %), 60 neck remnants (58.3 %), and 14 partial occlusions (13.6 %). A follow-up angiography (median duration, 30 months; range, 3–73 months) was performed in 80 lesions. Recanalisation was found in 28 lesions (35.0 %), of which 6 were complete occlusions, 18 were neck remnants, and 4 were partial occlusions, as determined by post-coiling angiograms. Among these lesions, 14 major recurrences were retreated with coiling (n = 12) and clipping (n = 2) without complications. Age (odds ratio [OR], 0.93; 95 % confidence interval [CI], −0.11 to −0.01; p = 0.03), the presence of a rupture (OR, 3.89; 95 % CI, 0.12 to 2.60; p = 0.03), and a wide aneurysm neck (OR, 6.40; 95 % CI, 0.57 to 3.14; p = 0.005) were significantly associated with the aneurysm recurrence, as determined by multivariable analyses.

Conclusion

Our study suggests that simple coiling of MCAB aneurysms is feasible and safe; however, it has limitations in durability, particularly in ruptured or wide-necked aneurysms and in young patients.

Y-stent-assisted coil embolisation of wide-necked aneurysms using a new fully retrievable and detachable intracranial stent: report of two cases

Endovascular treatment of wide-necked aneurysms poses a challenge for the endovascular therapist. The Y-stent-assisted technique has been used for stent-assisted coil embolisation for wide-necked bifurcation aneurysms. This technique has been described for basilar tip aneurysms and middle cerebral artery bifurcation aneurysms using Neuroform and Enterprise stents. We report 2 cases of wide-necked bifurcation aneurysms that were treated with Y-stent-assisted coil embolisation using a new, fully retrievable and detachable intracranial stent (Solitaire AB™). We describe the advantages of a fully retrievable and detachable stent and its feasibility of forming a Y configuration.

Potential advantages and limitations of the Leo stent in endovascular treatment of complex cerebral aneurysms

OBJECTIVE

The Leo self-expandable stent is a new retractable stent that is delivered via a conventional catheter. The aim of this study was to evaluate the use of this stent for endovascular treatment of complex aneurysms.

METHODS

Twenty-eight complex cerebral aneurysms (27 saccular and 1 fusiform) in 28 patients were treated electively. They were located at the internal carotid artery (17), basilar trunk (3), anterior cerebral artery (1), anterior communicating artery (3), vertebral artery (2) and middle cerebral artery (2). One aneurysm exhibited recanalization after primary endovascular treatment without stent. Clinical outcome was assessed with the modified Glasgow Outcome Scale.

RESULTS

Deployment of Leo stent was successful in 26 lesions, and difficulties in stent positioning due to tortuous cerebral circulation in 2 cases, which were treated with Neuroform stent. Additional coil embolization was performed in 26 lesions. No permanent neurological deficits were encountered consequent to endovascular procedure. Complete or partial occlusion immediately after stent deployment was achieved in all aneurysms. There was no immediate coil embolization was chosen in 3 cases because of subsequent reduced filling of the aneurysms with contrast agent on angiograms. There were 3 asymptomatic parent artery occlusion related to the deployment of the Leo stent, one stent migration. Follow-up revealed patent stents in the remaining cases. No angiographic recurrences arose.

CONCLUSION

The Leo stent is very useful for endovascular treatment of complex cerebral aneurysms because it is easy to navigate and place precisely. A drawback is that in-stent thrombosis caused by stent placement and stiffer delivery catheters to place larger stents.

A novel "Y" stent flow diversion technique for the endovascular treatment of bifurcation aneurysms without endosaccular coiling

BACKGROUND AND PURPOSE

Stent-assisted endovascular treatment and flow diversion techniques are increasingly used for the management of wide-neck intracranial aneurysms. We report our initial clinical experience using a new flow diversion technique for the endovascular management of bifurcation aneurysms.

MATERIALS AND METHODS

Eight bifurcation aneurysms were treated by placing 2 stents in Y-configuration with no accompanying endosaccular packing. This treatment technique aimed at flow diversion was selected in these cases because 1) the aneurysm was giant and causing mass effect, 2) the emanating branches were incorporated within the sac, or 3) the aneurysm was too small. Aneurysms were located at middle cerebral (5 aneurysms) and basilar artery bifurcations (3 aneurysms). Five aneurysms were small, 1 was large, and 2 were partially thrombosed giant. Closed-cell stents were used in all Y-stent placement procedures.

RESULTS

In all aneurysms, both stents could be placed at the intended locations without any procedural complication. Follow-up angiograms obtained at 3 months to 2 years demonstrated that all stents were patent except for one with asymptomatic P1 occlusion. Complete occlusion with remodelled bifurcation was observed in all middle cerebral artery bifurcation aneurysms and the large basilar tip aneurysm. Residual filling despite reduction in size was observed in both of the partially thrombosed giant aneurysms at 2-year and 3-month follow-up angiograms, respectively.

CONCLUSIONS

Flow diversion with double stent placement in Y-configuration provided successful and stable aneurysm occlusion. The technical and clinical results achieved are highly encouraging that this technique may contribute to the endovascular treatment of these complex bifurcation aneurysms.

Y-stent-assisted coil embolization of wide-neck intracranial aneurysms. A single center experience

This report evaluated the short and midterm results of the safety and effectiveness of the treatment technique with hybrid and non-hybrid Y-configured, dual stent-assisted coil embolization of wide-neck intracranial aneurysms, and reviewed the literature concerning this technique. Nine patients, eight with unruptured and one with ruptured aneurysms were included in the study. Of aneurysms embolized with a hybrid (with two different stents) and non-hybrid (with two identical stents) technique, three were located in the anterior communicating artery, three at the tip and one at the distal site of basilar artery, and two in the middle cerebral artery. All aneurysms included the orifices of bifurcation vessels. All aneurysms were stented and embolized during the same session. While Neuroform and Enterprise stents were used in the hybrid technique, two Enterprise stents were used in the non-hybrid technique. Dual Y-stent assisted coil embolization was performed successfully in eight of nine patients (88.9%), including five patients (55.6%) with hybrid and three patients (33.3%) with non-hybrid technique. No procedural complication, no mortality and no minor or major neurological complications were seen during the angiographic or clinical follow-up. When an attempt was made at passing the second stent through the first Enterprise stent, the stent protruded inside the aneurysm in one patient (11.1%). Hybrid or non-hybrid dual Y-stent-assisted coil embolization in the treatment of ruptured or unruptured wide-neck and complex intracranial aneurysms is a safe and effective method from the viewpoint of short and midterm results.

Endovascular treatment for cerebral aneurysms using stents

Endovascular stent placement combined with coil embolization is an established procedure for the treatment of intracranial aneurysms. We describe lesion outcome using stents for the treatment of intracranial aneurysms. Sixty-nine patients (30 females and 39 males; age range 12-78 years) treated with stent placement at Beijing Tiantan Hospital over a six-year period. Seventy- six cerebral aneurysms were encountered and 74 lesions were treated with 79 stents. Outcome was evaluated using the Glasgow Outcome Scale (GOS) score during a mean follow-up period of 32 months. Of the 74 stented aneurysms, 34 (45.9%) were located in the anterior circulation and 40 (54.1%) in the posterior circulation. Forty-eight (64.9%) aneurysms were small and 26 (35.1%) were large or giant. In 67 (90.5%) aneurysms embolization was completed by packing the aneurysm sac with platinum coils. In five small fusiform and four saccular aneurysms, the stent was used alone. Six procedure-related complications were observed and a cause of death in 7.2% of the patients. Follow-up angiography obtained at three months to one year in 68 (91.9%) aneurysms demonstrated complete occlusion in 43 aneurysms with a progressive thrombosis rate of 19.4% (six out of 31 aneurysms). Aneurysm recurrence occurred in four (5.8%) patients, three were treated with coil embolization and one with placement of another stent. Overall long-term outcome was good (GOS Score 4 or 5) in 92.8%, and fatal (GOS Score 1) in 7.2% of the patients. Intracranial stents can be a useful addition to coil embolization for complex broad-based aneurysms. Favorable overall long-term outcome can be achieved in 92.8% of patients when using endovascular stent placement techniques.

Treatment of a giant basilar artery aneurysm with a bridging stent and subsequent coil occlusion of the stent: case report

OBJECTIVE AND IMPORTANCE

To report the treatment of a symptomatic giant basilar artery aneurysm in a child.

CLINICAL PRESENTATION

A 7-year-old girl presented with a 2-month history of progressive right hemiparesis caused by a huge fusiform aneurysm of the basilar artery with compression of the brainstem. INTERVENTION OR TECHNIQUE: The patient was treated with a bridging bare stent and occlusion of the stent lumen with detachable coils.

CONCLUSION

The patient experienced immediate total occlusion of the aneurysm with almost total recuperation after 1 year.

The effect of stents on intra-aneurysmal hemodynamics: in vitro evaluation of a pulsatile sidewall aneurysm using laser Doppler anemometry

INTRODUCTION

Hemodynamic modification by means of flow diversion is increasingly used for treatment of intracranial aneurysms. Despite of promising results, there is still a paucity of methods to reliably predict long-term success of this technique. Laser Doppler anemometry (LDA) can be used to quantify the influence of stents on intra-aneurysmal flow in vitro.

METHODS

All experiments were performed with a pulsatile model of a sidewall aneurysm. A physiologic flow was created with a circulatory experimental setup, and a transparent non-Newtonian glycerol-water solution was used to substitute human blood. Flow velocity was measured with a one-component LDA system, recording flow components parallel and perpendicular to the parent vessel. Three different stents (Solitaire, Silk, Phenox flow diverter) were deployed over the aneurysm neck, respectively.

RESULTS

Flow reduction was 67.59% (inflow zone), 9.65% (dome) and 37.94% (outflow zone) by the Solitaire stent. The Silk stent reduced the flow by 58.15% (inflow zone), 89.06% (dome) and 90.06% (outflow zone). The Phenox flow diverter reduced the flow by 96.76% (inflow zone), 90% (dome) and 90.91% (outflow zone) when positioned with narrow stent struts but increased the velocity of up to seven times compared to the unstented model when placed with loose strut packing in the proximal part of the aneurysm.

CONCLUSION

LDA is a feasible method to quantify intra-aneurysmal flow and flow reduction efficacy of stents in vitro. Flow reduction was negligible with a standard self-expanding stent. For dedicated flow diverters, it depended both on stent design and on appropriate positioning.

Intracranial aneurysms: endovascular treatment

The incidence of subarachnoid hemorrhage is estimated at 5 to 10 per 100,000 per year. In patients who survive the initial hemorrhage, the repeat hemorrhage rate is 15% to 20% in the first 2 weeks after presentation and is associated with devastating clinical outcomes even graver than the initial rupture. The current options for aneurysm treatment are surgical clipping and, since the mid-1990s, neuroendovascular coil embolization. The former was at one time the gold standard of care, but consistent with the trend in modern medicine toward less-invasive procedures, the latter has steadily gained prominence. Although there is still controversy as to its long-term durability and safety, it is now the preferred procedure. This article describes the procedure's antecedents, rationale, and essential components. Mt Sinai J Med 77:279-285, 2010. (c) 2010 Mount Sinai School of Medicine.

Endovascular treatment of wide-neck middle cerebral artery aneurysms with stents: a review of 16 cases

BACKGROUND AND PURPOSE

MCA aneurysms are common and often pose technical challenges to interventionalists. Intracranial stents are widely used in treating wide-neck aneurysms in other locations. To evaluate the feasibility, effectiveness, and safety of stent placement in MCA aneurysms, we performed this retrospective study.

MATERIALS AND METHODS

Between October 2003 and May 2009, 16 patients with 16 wide-neck MCA aneurysms were treated with stents at our institution. We retrospectively collected and analyzed the data for these patients, including demographics, morphologic features of the aneurysms, treatment results, and follow-up.

RESULTS

Seventeen stents, including 12 Neuroform, 4 LEO, and 1 Enterprise, were successfully deployed in this series. Of the 13 aneurysms treated with stent-assisted embolization, complete occlusion was achieved in 9 aneurysms; residual neck remained in 1, and residual aneurysm was present in 3. Contrast stasis in the aneurysm sac was observed in the other 3 aneurysms treated with stent alone. Procedure-related complication occurred in 1 patient, leading to no permanent effect. The mRS score at discharge was 0-2 in 14 patients and 3-6 in 2. The angiographic follow-up results of 9 patients (mean, 5.6 months) showed that all aneurysms remained stable or improved; there was no in-stent stenosis, recurrence, or retreatment. The clinical follow-up (mean, 20.1 months) demonstrated no neurologic deterioration or rebleeding.

CONCLUSIONS

Our preliminary experience demonstrates that stent placement for the treatment of selected wide-neck MCA aneurysms is feasible. However, its safety and efficacy should be further evaluated by larger case series and more adequate follow-up.

Sole stenting technique for treatment of complex aneurysms

OBJECTIVE

Complex aneurysms such as fusiform and very small aneurysms (< 3 mm) are challenging in neurovascular and endovascular surgery. Author reports follow-up results of 9 cases treated by sole stent technique with pertinent literature review.

METHODS

A retrospective study was made of 9 patients who were treated by sole stenting technique for cerebral aneurysm between January 2003 and January 2009. Two of them had fusiform aneurysm, 5 had very small aneurysm, and 2 had small saccular aneurysm. Five patients had ruptured aneurysms and four had unruptured aneurysms. Seven aneurysms were located in the internal carotid artery (ICA), 1 in the middle cerebral artery (MCA) and 1 in the basilar artery. Follow-up cerebral angiography was performed at post-procedure 3 months, 6 months, and 12 months. Mean follow-up period is 30 months (ranged from 3 days to 30 months).

RESULTS

Aneurysm size was decreased in 6 of 9 cases on follow-up images and was not changed in 3 cases. Although total occlusion was not seen, patients had stable neurological condition and angiographic result. The procedural complication occurred in 2 cases. One was coil migration and the other was suboptimal deployment of stent, and both were asymptomatic. Re-bleeding and thromboembolic complication had not been occurred.

CONCLUSION

Sole stenting technique is relatively effective and safe as an alternative treatment for fusiform and very small aneurysms.

A combined approach to treatment of the dissecting middle cerebral artery fusiform aneurysm. A case report

SUMMARY

A fusiform aneurysm in the terminal M1 middle cerebral artery (MCA) segment was treated by a construction of a high-flow arterial extracranial-intracranial (EC-IC) bypass. Due to severe bypass vasospasms, local vasodilating agents together with percutaneous angioplasty and stent implantation were applied, but failed due to subsequent bypass occlusion. To remedy this complication a new bypass was created from a segment of the saphenous vein, followed by MCA aneurysm embolization and parent artery occlusion. One year after the surgery, the venous bypass remains patent and the aneurysm occluded, with the patient fully active, without any neurological sequelae.

Advances in Interventional Neuroradiology

In 2008 we witnessed a rapid advancement in stent technology, which is reflected in the high number of case reports, publications of case series, and randomized trials. Stents not only served for a combined intrasaccular and extrasaccular treatment of challenging aneurysms but also assisted the revascularization in acute and chronic ischemic conditions of the neurovascular system. Although a self-expanding nitinol semiopen cell stent is currently used for intracranial occlusive disease, a new retrievable closed-cell designed stent is widely used for aneurysms because of its easy delivery through a microcatheter in frequently tortuous head and neck as well as cerebrovascular circulation ( Figure 1 ). However, despite numerous publications in the field, the widespread acceptance of the use of stents to routinely treat carotid stenosis awaits the results of the multicenter randomized clinical trials that should be available in 2009. The role of interventional neuroradiology in the treatment of acute ischemic stroke continues to expand and excite interest.