Retrograde stenting through the posterior cerebral artery in coil embolization of the posterior communicating artery aneurysm

Introduction

Protection techniques using stents or balloons are occasionally limited in coil embolization of wide-necked posterior communicating artery (PcomA) aneurysms in which the PcomA originated from the aneurysm neck at an acute angle. Here, we present two cases undergoing retrograde stenting through the posterior cerebral artery in coil embolization of the PcomA aneurysms.

Methods

To perform retrograde stenting, a microcatheter used for stent delivery was advanced from the vertebral artery (VA) to the terminal internal carotid artery (ICA) via the ipsilateral P1 and the PcomA. The aneurysm sac was selected with another microcatheter for coil delivery through the ipsilateral ICA. Coil embolization was performed under the protection of a stent placed from the terminal ICA to the PcomA.

Results

Deployment of the stent was successful in both aneurysms treated using retrograde stenting by the VA approach. Coil deployment was performed through the jailed microcatheter at first. The microcatheter was repositioned through the stent struts later in one case and another microcatheter was inserted into the sac through the stent struts in the other case. Both aneurysms were occluded properly with the coils without procedure-related complications.

Conclusion

By providing complete neck coverage, retrograde stenting for coil embolization in wide-necked PcomA aneurysms seems to be a good alternative treatment strategy, when the aneurysms are incorporating extended parts of the PcomA, and the PcomA and P1 are big enough to allow passage of the microcatheter for delivery of the stent. However, this technique should be reserved for those cases with the specific vascular anatomy.     

Microguidewire protection of wide-necked aneurysms incorporating orifices of tortuous acute-angled vessels: a novel approach

Introduction

Protective/remodeling techniques for treating wide-necked intracranial aneurysms are constantly sought. However, their utility may be limited in lesions that incorporate the orifice of acute-angled efferent branch vessels. Furthermore, passage of a protective microcatheter may be challenging if a small branch is extremely tortuous. This study was conducted to explore a novel method of treating wide-necked aneurysms, utilizing microguidewire protection.

Methods

A microcatheter is first passed into parent artery (proximal to aneurysm) to position a microguidewire proximally in the involved branch. A second microcatheter is then inserted into aneurysmal sac. Advancement of the first microcatheter forces the microguidewire to shift, thus covering aneurysmal neck. A framing coil may then be placed within aneurysmal sac, under microguidewire protection. After completing initial coil insertion, easing of tension on the microcatheter allows separation of protective microguidewire and frame coil, confirming stability of the initial coil.

Results

This technique was applied to 11 intracranial saccular aneurysms of M1 segment (n?=?6), middle cerebral artery bifurcation (n?=?4), and anterior communicating artery (n?=?1) with success, combining stent protection in two patients. Coil embolization was thus facilitated, resulting in excellent outcomes for all patients. No morbidity or mortality was directly related to microguidewire protection.

Conclusion

Our small study suggests that microguidewire protection may be a safe alternative, if traditional remodeling or protective options are infeasible due to intrinsic vascular properties. This technique is particularly suited for treatment of wide-necked aneurysms where passage of protective microcatheters into involved branches is not achievable.     

Peri-stent aneurysm formation following a stent implant for stenotic intracranial vertebral artery dissection: a technical report of two cases successfully treated with coil embolization

Introduction

Although stenting for stenotic vertebral artery dissection (VAD) improves compromised blood flow, subsequent peri-stent aneurysm (PSA) formation is not well-known. We report two cases with PSA successfully treated with coil embolization.

Methods

Three patients with stenotic intracranial VAD underwent endovascular angioplasty at our institution because they had acute infarction in posterior circulation territory and clinical evidence of hemodynamic insufficiency. In two of three patients balloon angioplasty at first session failed to relieve the stenosis, and a coronary stent was implanted. Angiography immediately after stenting showed no abnormality in case 1 and minimal slit-like projection at proximal portion of the stent in case 2.

Results

Angiography obtained 16 months after the stenting revealed PSA in case 1. In case 2, angiography performed 3 months later showed that the projection at proximal portion enlarged and formed an aneurysm outside the stent. Because follow-up angiographies showed growth of the aneurysm in both cases, endovascular aneurysmal embolization was performed. We advanced a microcatheter into the aneurysm through the strut of existing stent and delivered detachable coils into the aneurysm lumen successfully in both cases. The post-procedural course was uneventful, and complete obliteration of aneurysm was confirmed on angiography in both cases.

Conclusion

Stenting for stenotic intracranial VAD may result in delayed PSA; therefore, follow-up angiographies would be necessary after stenting for stenotic intracranial arterial dissection. Coil embolization through the stent strut would be a solution for enlarging PSA.     

Coil embolization in precommunicating (A1) segment aneurysms of anterior cerebral artery

Introduction

Precommunicating (A1) segment aneurysms of the anterior cerebral artery are rare and often pose technical challenges for coil embolization due to their distinctive configurations. Clinical and radiologic outcomes of treating such aneurysms through endovascular coil embolization are presented herein.

Methods

Data accruing prospectively from May 2002 to August 2013 yielded 48 patients harboring 50 A1 segment aneurysms, each classified as proximal, middle, or distal by location. Clinical outcome of the patients and morphological outcome of the aneurysms were assessed, with emphasis on technical aspects of treatment.

Results

The aneurysms studied occupied either proximal (n?=?39), middle (n?=?6), or distal (n?=?5). Proximal aneurysms were largely directed posteriorly (80 %), and most (97 %) were devoid of branches. Middle and distal aneurysms were associated with the medial lenticulostriate artery, cortical branches, or fenestrations. The preshaped “S” and steam-shaped “S” microcatheters facilitated aneurysm selection in 60 % of lesions. Single-microcatheter technique was most commonly applied for coil embolization (62 %), followed by balloon protection (16 %). Successful aneurysmal occlusion could be achieved in 76 % of the patients, with no procedure-related morbidity and mortality. At final follow-up (mean interval, 29.9 months), stable aneurysmal occlusion was sustained in 93 % of the patients (40/43).

Conclusion

A1 segment aneurysms are amenable to safe and efficacious endovascular coil embolization by adjusting procedural strategy to accommodate distinctive anatomic configurations.     

Endovascular coil embolization of middle cerebral artery aneurysms of the proximal (M1) segment

Introduction

Proximal middle cerebral artery (M1 segment) aneurysms have various configurations and are distinct from middle cerebral artery bifurcation aneurysms. We present the clinical and radiological results of coil embolization of the M1 segment aneurysms.

Methods

From a prospective database, we retrieved the data for 59 consecutive patients harboring 60 M1 aneurysms that were treated with endovascular coil embolization from January 2006 to May 2012. We assessed the clinical outcomes of the patients and morphological outcomes of the aneurysms using the Raymond classification.

Results

The aneurysms were located on the superior wall of the M1 segment in 43 and on the inferior wall in 17. Superior-wall aneurysms were related to the frontal cortical artery and the lateral lenticulostriate perforator while inferior-wall aneurysms were to the temporal cortical artery. With coil embolization, complete aneurysmal occlusion or residual neck could be achieved in 52 aneurysms (86.7 %) and residual aneurysm in 8. The microcatheter protection technique was most commonly used for coil embolization (41.7 %) followed by single microcatheter (31.7 %), double microcatheter (23.3 %), and stent protection (3.3 %). There was no procedure-related morbidity or mortality. Follow-up angiography more than 6 months after embolization (n?=?46; mean 12.4 months) demonstrated stable occlusion in 40 (87.0 %), minor recanalization in 4 (8.7 %), and major recanalization in 2 (4.3 %). One patient experienced delayed cerebral infarction without permanent neurologic deficit.

Conclusion

Coil embolization in M1 aneurysms seems to be safe and efficacious, although it may require various technical strategies due to distinct anatomic configurations.     

Stent-assisted coil embolization of wide-necked posterior inferior cerebellar artery aneurysms

Introduction

Endovascular coil embolization of posterior circulation aneurysms has advantages over a surgical approach. However, the application of coil embolization is sometimes limited in wide-necked posterior inferior cerebellar artery (PICA) aneurysms, which are incorporating the origin of the branch. Presented here is a series of patients who were subjected to stent-supported coil embolization of PICA aneurysms.

Methods

From a prospective data repository, we retrieved records of seven consecutive patients with PICA aneurysms, all of whom were treated by stent-assisted coil embolization between January 2010 and November 2012. Outcomes were analyzed in terms of aneurysm morphology and clinical status.

Results

In all seven instances, the stents were placed from proximal PICA to vertebral artery (VA). A retrograde approach, via contralateral VA, was performed in five patients, where the origin of PICA from VA assumed an acute angle. In the other two patients, where the angles were obtuse, the stenting was done antegrade, via ipsilateral VA. Out of five patients with retrograde approach, single puncture and a single guiding catheter sufficed in three patients, whereas the remaining two patients required dual puncture and two guiding catheters. Endovascular treatments, as performed, resulted in excellent outcomes for all seven patients, although an asymptomatic thrombus developed in one patient with a ruptured aneurysm.

Conclusion

For coil embolization of PICA aneurysm requiring stent protection, either ipsilateral or contralateral VA access routes may be used, depending on the angle of PICA origin and the configuration of the aneurysm.     

Coil embolization of intracranial saccular aneurysms using the Low-profile Visualized Intraluminal Support (LVIS™) device

Introduction

The novel Low-profile Visualized Intraluminal Support (LVIS?, LVIS and LVIS Jr.) device was recently introduced for stent-supported coil embolization of intracranial aneurysms. Periprocedural and midterm follow-up results for its use in stent-supported coil embolization of unruptured aneurysms are presented herein.

Methods

In this prospective multicenter study, clinical and radiologic outcomes were analyzed for 55 patients with saccular aneurysms undergoing LVIS-assisted coil embolization between October 2012 and February 2013. Magnetic resonance angiography or digital subtraction angiography was performed to evaluate midterm follow-up results.

Results

The standard LVIS device, deployed in 27 patients, was more often used in internal carotid artery (ICA) aneurysms (n?=?19), whereas the LVIS Jr. (a lower profile stent, n?=?28) was generally reserved for anterior communicating artery (n?=?14) and middle cerebral artery (n?=?8) aneurysms. With LVIS-assisted coil embolization, successful occlusion was achieved in 45 aneurysms (81.8 %). Although no instances of navigation failure or stent malposition occurred, segmentally incomplete stent expansion was seen in five patients where the higher profile LVIS was applied to ICA including carotid siphon. Procedural morbidity was low (2/55, 3.6 %), limited to symptomatic thromboembolism. In the imaging of lesions (54/55, 98.2 %) at 6-month follow-up, only a single instances of major recanalization (1.9 %) occurred. Follow-up angiography of 30 aneurysms (54.5 %) demonstrated in-stent stenosis in 26 (86.7 %), with no instances of stent migration. Only one patient suffered late delayed infarction (modified Rankin Scale 1).

Conclusion

The LVIS device performed acceptably in stent-assisted coil embolization of non-ruptured aneurysms due to easy navigation and precise placement, although segmentally incomplete stent expansion and delayed in-stent stenosis were issues.     

Angiographic outcome after endovascular therapy for anterior communicating artery aneurysms: correlation with vascular morphological features

Purpose

The purpose of this study is to analyze the effect of morphological features on angiography after endovascular embolization for anterior communicating artery (AcoA) aneurysms.

Materials and methods

We conducted a retrospective case review of 32 consecutive patients (19 males and 13 females) with AcoA aneurysms treated by endovascular coil embolization between February 2003 and August 2011. Mean age was 61?years (range 36?C90?years). Twenty-eight aneurysms were ruptured and 4 were unruptured. We evaluated morphological features included direction of the dome, dome size, dome to neck ratio, presence of irregularity, and angle between A1 segment of the anterior cerebral artery and C1 segment of the internal carotid artery. Immediate angiographic results (complete or incomplete occlusion) and the occurrence of procedural complications (aneurysmal rupture and thromboembolic events) were correlated with morphological features. Fisher??s exact test was used for statistical analysis.

Results

A single factor significantly associated with incomplete occlusion was superior dome direction (p?=?0.037). Other morphological features did not correlate with angiographical results. There was no correlation between morphological features and procedural complications.

Conclusion

Incomplete occlusion after coil embolization for AcoA aneurysms is more common in cases of superior dome direction.     

Woven Endobridge (WEB) Device for endovascular treatment of ruptured intracranial wide-neck aneurysms: a single-center experience

Introduction

Endovascular treatment of ruptured wide-neck bifurcation aneurysms presents a challenge. While still under evaluation, the Woven Endobridge (WEB) aneurysm embolization system has so far shown promising results in the treatment of complex bifurcation aneurysms. We aimed to evaluate the feasibility and short-term follow-up of endovascular treatment of ruptured wide-neck aneurysm with the WEB device.

Methods

Six patients referred to our institution for acute symptomatic subarachnoid hemorrhage (SAH) and treated with the WEB device were enrolled in this study. Clinical presentations, technical details, intraoperative and postoperative complications, and outcomes were recorded. Immediate and 3-month angiographic results were also evaluated.

Results

Three middle cerebral artery (MCA) and three anterior communicating artery aneurysms were treated between 1 and 14 days after rupturing. Average dome width was 5.8 mm (range 5–7), average neck size was 4.5 mm (range 4–5), and average dome-to-neck ratio was 1.3 (range 1–1.7). The WEB system was the exclusive treatment and was successfully deployed in all cases. Per procedural thromboembolic events occurred in two cases and were treated with intra-arterial administration of antiplatelet agents without any clinical consequences. The modified Rankin Scale (mRS) score at discharge was 0 for all patients. The 3-month angiographic follow-up showed adequate occlusion in four of our six patients (67 %).

Conclusion

From this preliminary study, the high feasibility rate and lack of need for systematic antiplatelet agents favor the WEB device providing a solution for endovascular treatment of ruptured wide-neck bifurcation aneurysms during the acute phase. However, further studies are needed to evaluate the complication rate and long-term efficiency.     

Treatment of elastase-induced intracranial aneurysms in New Zealand white rabbits by use of a novel neurovascular embolization stent device

Introduction

This study aims to test a novel balloon expandable stent covered with a polytetrafluoroethylene membrane (neurovascular embolization cover (NEC), NFocus Neuromedical, Palo Alto, California) regarding angiographic and histologic aneurysm occlusion. Radiopacity, stent placement, navigation, flexibility, and intimal proliferation were also evaluated.

Methods

Eight aneurysms were induced in New Zealand white rabbits. Digital subtraction angiography (DSA) was performed directly after stent placement and after 5 and 10 min. Four and 8 weeks after stent placement, an intra-arterial DSA control was performed. The animals were then sacrificed and the aneurysms histologically evaluated.

Results

The radiopaque markers were clearly visible. Although all the stents were easily navigated into the subclavian artery, the limited flexibility of the stent resulted in straightening of the vessel in four cases. As a result, exact stent placement was achieved and acutely confirmed in only two cases. However, at sacrifice, angiographic and histologic occlusion was noted at follow-up in five aneurysms.

Conclusion

In tortuous anatomy, the relative stiffness of the stent makes exact stent placement challenging. This may have been exacerbated by the movement of the vessels due to proximity to the heart in this model. Future studies should evaluate whether existing residual flow into an aneurysm lumen might lead to embolization without any additional treatment. Anticoagulation remains a very important part of aneurysm treatment with stents. The trend toward aneurysm occlusion by excluding it from the blood circulation seems a promising method in future endovascular therapy. The NEC device shows good potential.     

The sheeping technique or how to avoid exchange maneuvers

Introduction

The arteries of bifurcation aneurysms are sometimes so angulated or tortuous that an exchange maneuver is necessary to catheterize them with a balloon or stent delivery catheter. Because of the risk of distal wire perforation associated with exchange maneuvers, we sought to find an alternative technique.

Methods

Our experience shows that a microcatheter tends to preferentially follow a previously placed microcatheter, even if the initial catheterization might be challenging. Accessing an artery with two microcatheters simultaneously may thus be an alternative to an exchange maneuver. Because of this tendency for catheters to behave like sheep following one another, we named this method the sheeping technique (ST). The ST consists of (a) first placing a 1.7 French microcatheter into the division branch requiring balloon or stent protection to straighten the course of the arteries in order to facilitate and (b) positioning in the same artery of a larger and stiffer balloon or stent microcatheter. Once the second balloon or stent microcatheter is in place, the first microcatheter can be pulled back and used to coil the aneurysm.

Results

Between January 2009 and December 2012, The ST was successfully used in 208/246 procedures (85 %). Conversion to an exchange maneuver was necessary in 38/246 (15 %). There were no arterial perforations or ischemic events related to the handling of both microcatheters.

Conclusion

The sheeping technique may improve safety by replacing the need for an exchange maneuver during difficult balloon- or stent-assisted coiling.     

Leo stent for endovascular treatment of intracranial aneurysms: very long-term results in 50 patients with 52 aneurysms and literature review

Introduction

The Leo stent was the first retrievable stent for endovascular treatment of intracranial aneurysms (IAs). We report our experience with this device with emphasis on very long-term follow-up.

Methods

This study was approved by authors’ ethical committee. A retrospective review of our prospectively maintained database identified all patients treated for a saccular IA with this stent in our institution. Technical issues and immediate and long-term outcomes (at least 12 months) were evaluated.

Results

Between 2004 and 2015, 50 patients with 52 IAs were identified. In two patients, the stent could not safely be placed (failure rate = 3.8%). Among 48 treated patients with 50 IAs, there were 44 women and 4 men (mean age, 53 years). Mean aneurysm diameter was 7.2 mm. All IAs but six were wide-necked. There was no immediate morbidity or mortality. Anatomical results included 76% complete occlusions, 22% neck remnants, and 2% incomplete occlusions. Mean follow-up was 50.2 months (range, 12–139 months). Two patients had delayed TIAs but long-term morbidity rate remained = 0%. At follow-up, occlusion was stable in 68% IAs, showed thrombosis in 12%, and recanalization in 20% IAs. Complementary treatment was required in 8% IAs. Final results showed 70% complete occlusions, 24% neck remnants, and 6% incomplete occlusions. Asymptomatic stent occlusion and significant stenosis occurred in one and two cases, respectively.

Conclusion

The Leo stent is safe and effective for treatment of wide-necked saccular IAs. Very long-term results show high rates of adequate and stable occlusion. Moreover, the stent is well tolerated.

     

Does stent type impact coil embolization outcomes in extended follow-up of small-sized aneurysms (< 10 mm)?

Purpose

Self-expandable stents have enabled endovascular treatment of wide-necked aneurysms (ordinarily viewed as technically prohibitive), with favorable outcomes. However, the impact of stent type on occlusive stability has not been adequately investigated. In small-sized unruptured saccular aneurysms, we generated estimates of stent-assisted coil embolization outcomes during follow-up monitoring. Stent type and other risk factors linked to recanalization were analyzed.

Methods

A cohort of 286 patients harboring 312 small-sized unruptured aneurysms (<?10 mm) was subjected to mid-term and extended follow-up monitoring after stent-assisted coiling. Three types of stents (Enterprise, 192; Neuroform, 27; LVIS, 93) were deployed in this population; all medical records and radiologic data of which were reviewed. Mid-term recanalization rates and related risk factors were assessed using binary logistic regression analysis.

Results

A total of 49 aneurysms (15.7%) displayed recanalization at 6 months postembolization, with 34 and 15 instances of minor and major recanalization, respectively. Multivariate analysis indicated that wide-necked aneurysms (>?4 mm) (HR?=?2.362; p?=?0.017), incomplete occlusion at time of coiling (HR?=?2.949; p?=?0.002), and stent type (p?=?0.048) were significant factors in mid-term recanalization, whereas hypertension (p?=?0.095) and packing density ≤?30% (p?=?0.213) fell short of statistical significance. Compared with Enterprise (HR?=?2.828) or Neuroform (HR?=?4.206) stents, outcomes proved more favorable with use of LVIS.

Conclusions

Above findings demonstrate that in addition to occlusive status at time of coil embolization and neck size, stent type may affect follow-up outcomes of stent-assisted coil embolization in small-sized aneurysms. LVIS (vs Enterprise or Neuroform stents) performed best during follow-up monitoring in terms of limiting recanalization.

     

Low rates of recanalization for wide-necked aneurysms treated with stenting after balloon-assisted coiling: combination of techniques delivers stable and improved results during follow-up

Purpose

In the treatment of wide-necked aneurysms, stenting may be required after balloon-assisted coiling (BAC) for reconstructing the lumen/flow of the parent artery in cases of coil herniation. The potential benefits and complications of both techniques remain unclear when used together. Our aim was to assess the safety and long-term angiographic outcomes of stenting after BAC.

Methods

Retrospective review of 87 unruptured wide necked aneurysms (in 80 patients) treated with BAC and requiring stent placement at the final stage of the procedure due to coil prolapse. Aneurysm characteristics, technical issues, clinical records, and MR results were assessed. Post-treatment and follow-up angiograms were evaluated by two independent reviewers and categorized as “stable,” “further thrombosis,” or “recanalization.”

Results

The mean maximum diameter was 9.1 ± 4.7 mm and aspect ratio 1.20?±?0.47. Complete and near-complete initial occlusion were observed in 53 (60.9%) and 28 (32.2%) of all treated aneurysms, respectively. Angiographic follow-up (80 aneurysms; mean, 34.68 ± 25.26 months) revealed stability and further thrombosis in 92.4% (74/80). Recanalization was observed in six cases (7.5%, 6/83), four of which were retreated. No significantly different outcomes were found in terms of aneurysm size (p?=?0.641). Transient and reversible procedure-related complications occurred in eight (9.2%), minor permanent deficits in 2.3%, and major deficits, including death, in four cases (4.6%).

Conclusion

Our results suggest that treatment of wide-necked aneuryms with stent placement after BAC yields low recanalization rates and enhanced angiographic outcomes in long-term follow-up.

     

Solitaire AB stent-assisted coiling of wide-necked intracranial aneurysms: short-term results from a prospective, consecutive, European multicentric study

Introduction

Solitaire AB stent-assisted coiling facilitates the endovascular treatment of wide-necked intracranial aneurysms. Solitaire Aneurysm Remodeling is the first prospective, consecutive, European multicentric study whose main objective was to evaluate the safety, short-, and long-term efficacy of the Solitaire AB stent. This first analysis is focused on the short-term results.

Methods

After exclusion of one patient, 66 Solitaire AB stents were used to treat via endovascular approach 64 aneurysms (63 patients) in seven European centers. Technical and clinical complications were recorded. A core laboratory evaluated the angiographic efficacy by using the Raymond classification scale.

Results

The mean width of aneurysm sac was 7.5 mm, and the mean diameter of aneurysm neck was 4.7 mm. Complete occlusion was achieved in 27 aneurysms (42.2 %); neck remnant was seen in 25 aneurysms (39.1 %) and aneurysm remnant in 12 aneurysms (18.7 %). Technical and clinical complications related to the procedure were encountered in eight patients (12.7 %). Postprocedural modification of the clinical status was observed in one patient (1.6 %). No patients died (0 %); one had a permanent deficit (1.6 %), and one had a transient deficit (1.6 %). Treatment-related mortality was 0 %, and permanent morbidity was 1.6 %.

Conclusion

The Solitaire AB stent has an excellent rate of technical success navigation with the absence of dislodgement. The safety and short-term efficacy are comparable to those previously reported with coiling alone. Mid- and long-term follow-up will be required to elucidate the impact of the Solitaire AB stent on recanalization rate.     

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.     

Infundibular dilation and aneurysm at the origin of the posterior communicating artery: differential diagnosis by CT angiography

Introduction

Infundibular dilation (ID) and aneurysm at the internal carotid artery (ICA)–posterior communicating artery (PComA) junction can be difficult to distinguish but may differ in clinical significance. The aim of this study was to evaluate the utility of CT angiography (CTA) in differentially diagnosing IDs and small unruptured aneurysms at the ICA–PComA junction.

Methods

This retrospective study comprised 88 patients diagnosed with 107 protrusions (70 IDs and 37 aneurysms <5 mm; 19 bilateral lesions) at the ICA–PComA junction who underwent both CTA and digital subtraction angiography (DSA). Two neuroradiologists independently reviewed CTA and DSA images according to these criteria: (a) size (maximum dimension <3 or ≥3 mm), (b) shape (triangular or round/oval/irregular), (c) aneurysmal neck (absent or present), (d) horizontal direction (posteriomedial or posteriolateral), and (e) PComA origin (apex, no PComA, or base). The intermodality (between CTA and DSA) and interobserver (between the two readers) agreement were determined for each finding. We also evaluated the sensitivity and specificity of CTA for distinguishing ID and aneurysm, using DSA as the reference standard.

Results

The mean κ values of intermodality agreement for the size, shape, aneurysmal neck, horizontal direction, and PComA origin were 0.88, 0.87, 0.84, 0.71, and 0.56, respectively. All interobserver agreements of CTA and DSA were excellent. The sensitivity, specificity, and accuracy of CTA for differentiating aneurysms from IDs were 94.6, 100, and 98.0 %, respectively.

Conclusion

CTA may be a useful noninvasive modality for differential diagnosis of ID and aneurysm at the ICA–PComA junction.     

Use of Triple Microcatheters for Endovascular Treatment of Wide-Necked Intracranial Aneurysms: A Single Center Experience

Objective

The dual microcatheter technique is common practice for coil embolization of a wide-necked aneurysm, due to safety and efficacy. However, technical limitations of some complex configurations may necessitate additional microcatheters to bolster coil stability, compact the coil, or for protection. Described herein is a triple microcatheter technique for endovascular management of wide-necked intracranial aneurysms.

Materials and Methods

Data accruing prospectively between January 2006 and October 2014 on simultaneously executed triple microcatheter coil embolization procedures done in 38 saccular aneurysms were reviewed. Clinical and morphological outcomes were assessed, with emphasis on technical aspects of treatment.

Results

The triple microcatheter technique was successfully applied to all 38 saccular aneurysms, involving the posterior communicating artery (n = 13), the middle cerebral artery (n = 10), the basilar tip (n = 7), the anterior cerebral artery (n = 5), and the internal carotid artery (n = 3). Stent protection was added in four patients and balloon remodeling in one. Dual microcatheters (n = 24) were usually deployed to deliver the coil within sacs of aneurysms, with the additional microcatheter used for protection. Otherwise, triple microcatheters were deployed for coil delivery (n = 11) or coils were delivered via a single microcatheter, with dual microcatheters deployed for protection (n = 3). Successful occlusion of aneurysms was achieved in 89.5% of cases, with no procedure-related morbidity or mortality. Stable occlusion was maintained in 72.2% (26/36) of the aneurysms at the final follow-up (mean interval, 30.2 ± 22.7 months).

Conclusion

The outcomes of this limited study suggest that the triple microcatheter technique may be an effective and safe therapeutic option for wide-necked aneurysms, using technical strategies tailored to complex angio-anatomic configurations.     

Frequency and predictors of endoleaks and long-term patency after covered stent placement for the treatment of intracranial aneurysms: a prospective, non-randomised multicentre experience

Objective

We investigated immediate/late endoleaks and long-term patency following stent-graft placement for treatment of intracranial aneurysms located within the distal internal carotid artery (ICA) or vertebral artery (VA).

Methods

Forty-five aneurysms in 41 patients receiving covered stents in three centres were followed. Outcome measures included aneurysm occlusion rate, endoleaks, late in-stent stenosis rate, clinical improvement, neurological deficiencies and death.

Results

Total aneurysm exclusion was achieved in 69.2% (n?=?27), with 30.8% (n?=?12) experiencing immediate residual endoleaks. Angiographic follow-up (mean 43.5?±?14.3 months) revealed that 87.2% (n?=?34) were completely occluded with only 12.8% (n?=?5) showing residual endoleaks. Predictors of immediate endoleaks in our patient group were stent number (P?=?0.023) and stent diameter (P?=?0.022), while predictors of late endoleaks in our patient group were stent diameter (P?=?0.035) and stent angulation (P?=?0.021). Late in-stent stenosis rates were 18.0?±?13.3 and 29.0?±?18.5% compared with the period immediately following implantation at 2- and 6-year follow-ups respectively. Smoking (P?=?0.017) and stent angulation (P?=?0.020) were predictors of late in-stent stenosis.

Conclusion

Treating intracranial aneurysms with Willis stent-grafts has an acceptable immediate and late occlusion rate and long-term stented artery patency rate.

Key Points

? Covered stents can be a treatment option for intracranial aneurysms. ? Technical success for treating distal ICA and VA aneurysms can reach 97.6%. ? However immediate and late endoleaks occur in 30.8 and 12.8% respectively. ? The number, diameter and angulation of stents are possible predictors of endoleaks. ? Smoking and stent angulation seem to predict late in-stent stenosis.     

Treatment of carotid siphon aneurysms by use of the Willis stent graft: an angiographic and histopathological study

Objective

We designed a carotid siphon (CS) aneurysm model in dogs to test a new stent graft (the Willis covered stent) and compared tissue reaction over 12-month follow-up versus a comparison group with stents implanted in straight vessels.

Methods

Twenty-four saccular sidewall aneurysms (group A) and 12 CS aneurysms (group B) were created surgically. A Willis stent graft was implanted in each aneurysm. Angiography was performed immediately and at 1-, 3-, 6- and 12-month post-implantation to investigate aneurysm isolation, endoleak, stent angulation, parent artery (PA) patency and restenosis. Light and scanning electron microscopy were used to identify aneurysmal sac thrombi, intima hyperplasia and endothelial progress.

Results

Immediate angiography demonstrated mild endoleak in two aneurysms and three stent angulations in group B. Follow-up at 12 months revealed resolved endoleaks, occlusion in one PA and mild stenosis in three in group B. In group A, occlusion occurred in one PA and mild stenosis in two. Light microscopy revealed new intima, and all aneurysm sacs were filled with thrombi. In group B, endothelial progress was complete at 12 months, and closely correlated with haemodynamic changes.

Conclusions

Application of a Willis stent graft is a feasible method of treating CS aneurysms, and it exhibits a prolonged endothelial progress compared with that in straight vessels.