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

Endovascular management of saccular aneurysms of the proximal A1 segment: technical particularities and long term outcomes

BACKGROUND

Saccular aneurysms of the proximal A1 segment (SAPA1) are rare, but their treatment is challenging and scarcely described in the literature. We report the immediate and long term outcomes of their endovascular management.

METHODS

We retrospectively analyzed all consecutive SAPA1 cases treated endovascularly at our center between 2003 and 2023. Per procedural complications and radioclinical outcomes were prospectively recorded.

RESULTS

Among 2468 patients followed up for aneurysms, 12 (0.49%) had an SAPA1 (average age 53.8±9.6 years, 9 women). The SAPA1 averaged 3.3 mm, all posteriorly oriented. Ten were ruptured (83.3%). Initial treatments included conventional coiling or balloon assisted coiling (CC/BAC) for nine aneurysms, and proximal A1 segment focal occlusion (PA1FO) for three. Initial occlusion was deemed satisfactory in all instances: total occlusion in eight cases (67%) and subtotal occlusion in four cases (33%). Four aneurysmal perforations occurred (33%), all during CC/BAC on ruptured aneurysms. Over a 10.2 year average follow-up, six recanalizations (50%) were noted, all after initial CC/BAC: three were early (≤14 days), with one causing fatal rebleeding. No recanalizations after PA1FO was observed (five in total, two as a complement after CC/BAC). Favorable clinical outcomes (modified Rankin Scale score of 0-2) were seen in 91% of cases (11/12) at the last follow-up.

CONCLUSIONS

Selective coiling of the aneurysmal sac is technically difficult due to their small size and the complex microcatheterization pathway. This method presents a significant risk of aneurysmal perforation, especially in ruptured cases, and a high rate of recanalization. PA1FO, when collateralization permits, appears to be a reliable therapeutic alternative offering favorable long term outcomes.

Surgery Versus Endovascular Treatment for Proximal Anterior Cerebral Artery Aneurysms: A Meta-Analysis

BACKGROUND

Proximal anterior cerebral artery (PACA) aneurysms account for less than 1% of all intracranial aneurysms. These aneurysms possess a challenge to surgeons due to their small size, wide base, fragile wall, and accompanying vascular anomalies. Surgery and endovascular treatment are both effective treatment options for PACA aneurysms but there is currently no consensus on which is the method of choice.

OBJECTIVE

A systematic review and meta-analysis was conducted to investigate treatment strategies for aneurysms at proximal anterior cerebral artery.

MATERIAL AND METHODS

The Cochrane Library, EMBASE, PubMed, and Web of Science databases were systematically searched for studies published between January 01, 2000 and December 01, 2020 that investigated surgery and/or endovascular treatment for patients with PACA.

RESULTS AND CONCLUSIONS

Nineteen retrospective studies involving 358 patients met the inclusion criteria. Among these patients, 150 were treated surgically and 208 were treated using an endovascular technique. Preoperative morbidity was significantly greater in the surgical patients compared with the endovascular treated patients but there was no difference between groups in procedural related morbidity. The rates of favorable clinical outcome at time of discharge and at follow-up were statistically significantly greater in the endovascular group compared with the surgical group. Procedural related mortality was 8.7% for the surgical group and 1% in the endovascular group. In summary, our meta-analysis emphasized the safety and efficiency of endovascular treatment, and concluded that it was superior to surgery in acquiring favorable clinical outcome and reducing the perioperative complications. However, surgery was still the preferred treatment strategy for ruptured PACA aneurysms. Preoperative evaluation seems to be of great vital.

Endovascular Treatment in Precommunicating Segment Aneurysms of Posterior Cerebral Artery

BACKGROUND

Precommunicating (P1) segment aneurysms of the posterior cerebral artery are rare, with few studies reported to date. Herein, we address the clinical and radiologic outcomes of their endovascular treatment.

METHODS

For this study, we retrieved prospectively collected data on 35 consecutive patients with 37 P1 aneurysms, analyzing the clinical ramifications and morphologic outcomes of treatment. All subjects received endovascular interventions between January 2001 and October 2021.

RESULTS

There were 16 aneurysms (43.2%) of P1 segment sidewalls and 21 (56.8%) at P1/posterior communicating artery junctions. Five (13.5%) were fusiform, and 14 (37.8%) were ruptured. In 14 patients (40%), 16 aneurysms (43%) were associated with intracranial arterial occlusive disease of the anterior circulation. Selective coiling was undertaken in 34 aneurysms (91.9%), using single (n = 24) or double (n = 4) microcatheters, microcatheter protection (n = 2), or stents (n = 4); and trapping was done in 3 (8.1%). No procedure-related morbidity or mortality resulted. Excluding the trapped lesions, angiographic follow-up of 29 aneurysms obtained >6 months after embolization (mean, 12.4 month) revealed stable occlusion in 21 (72.4%), with some recanalization in the other 8 (minor: 3/29, 10.4%; major: 5/29, 17.2%).

CONCLUSIONS

Aneurysms of P1 segment (vs. other locations) are strongly associated with intracranial arterial occlusive disease of the anterior circulation and thus are likely flow related. Endovascular treatment of such lesions seems safe and efficacious, despite the array of technical strategies that their distinctive anatomic configurations impose.

Navigating complexity: a comprehensive review of microcatheter shaping techniques in endovascular aneurysm embolization

The endovascular intervention technique has gained prominence in the treatment of intracranial aneurysms due to its minimal invasiveness and shorter recovery time. A critical step of the intervention is the shaping of the microcatheter, which ensures its accurate placement and stability within the aneurysm sac. This is vital for enhancing coil placement and minimizing the risk of catheter kickback during the coiling process. Currently, microcatheter shaping is primarily reliant on the operator's experience, who shapes them based on the curvature of the target vessel and aneurysm location, utilizing 3D rotational angiography or CT angiography. Some researchers have documented their experiences with conventional shaping methods. Additionally, some scholars have explored auxiliary techniques such as 3D printing and computer simulations to facilitate microcatheter shaping. However, the shaping of microcatheters can still pose challenges, especially in cases with complex anatomical structures or very small aneurysms, and even experienced operators may encounter difficulties, and there has been a lack of a holistic summary of microcatheter shaping techniques in the literature. In this article, we present a review of the literature from 1994 to 2023 on microcatheter shaping techniques in endovascular aneurysm embolization. Our review aims to present a thorough overview of the various experiences and techniques shared by researchers over the last 3 decades, provides an analysis of shaping methods, and serves as an invaluable resource for both novice and experienced practitioners, highlighting the significance of understanding and mastering this technique for successful endovascular intervention in intracranial aneurysms.

Microneurosurgical management of aneurysms of the A1 segment of the anterior cerebral artery: Anatomy and surgical technique

Background:

Aneurysms of the A1 segment of the anterior cerebral artery (ACA) are rare and have characteristics differentiating them from other intracranial aneurysms. Their microsurgical management is challenging and requires different strategies. In this article, we review the surgical anatomy of the A1 segment of the ACA with cadaveric dissections and describe the microsurgical management of complex A1 aneurysms with illustrative cases.

Methods:

A right pterional craniotomy and Sylvian dissection were performed on a formalin-fixed and silicone-injected cadaver head to depict the key anatomic structures and surgical corridors for microsurgical clipping of A1 segment aneurysms. The microneurosurgical management of ruptured and unruptured aneurysms of the A1 segment of the ACA is described with case illustrations.

Results:

The A1 segment of the ACA can be subdivided into proximal, middle, and distal subsegments, the former having abundant perforating branches. Both patients treated with microsurgical clipping had excellent and durable outcomes and postoperative cerebral angiograms showed complete aneurysm occlusion.

Conclusion:

Small A1 aneurysms may require early treatment as their rupture risk appears to be higher. A1 aneurysms are usually embedded in perforators, especially those arising from the proximal A1 subsegment, and require careful distal to proximal microdissection and strategic placement of the aneurysm clip blades. The approach, arachnoid dissection, and angles of attack are carefully planned after accounting for the aneurysm dome projection, precise location of the aneurysm neck and perforators, and the presence or absence of subarachnoid hemorrhage.

Hemodynamic impact of proximal anterior cerebral artery aneurysm: Mind the posteriorly projecting ones!

Intracranial aneurysm projected posteriorly is associated with high risk of aneurysm rupture. In order to investigate the biomechanical mechanisms for the adverse event, three-dimension intracranial cerebral aneurysms were constructed based on clinical data, and we numerically compared effect of location, position, size, and shape of aneurysm on hemodynamic conditions including velocity, pressure, and wall shear stress (WSS). The numerical results showed that the aneurysm projected posteriorly even at small sizes led to abnormal hemodynamic environment, which was featured by a local high pressure and stress concentration near aneurysm neck area. Moreover, the one located at the proximal A1 segment and ellipsoidal aneurysm would further worse local hemodynamic environment, causing high local stresses. These findings indicated the potential mechanical mechanism for high rupture rate of the aneurysms projected posteriorly, underscoring importance of early and accurate diagnosis and promptly treatment for improved the clinical outcome, even if these aneurysms are of small sizes.

Endovascular treatment for aneurysms at the A1 segment of the anterior cerebral artery: current difficulties and solutions

Aneurysms located at the A1 segment of the anterior cerebral artery are considered rare and unique entities. Endovascular treatment (EVT) is effective in preventing aneurysmal bleeding. However, EVT for A1 aneurysms is difficult due to their distinctive configurations. A current review of EVT for A1 aneurysms is lacking. Therefore, we focused on the available literature on this specific issue. To more clearly expound this entity, we also provided some illustrative cases. The A1 segment can be equally divided into the proximal, middle, and distal segments. Proximal aneurysms are most common and difficult to treat via EVT. The A1 segment has a complex anatomy and many important branches. Due to the small size, predominant posterior direction, and sharp upturn of the microcatheter from the parent artery, microcatheter positioning and support is difficult for A1 aneurysms. EVT for A1 aneurysms mainly includes reconstructive and deconstructive strategies. The complications of EVT for A1 aneurysms include aneurysmal perforation, thromboembolic events, and coil protrusion related to stent-assisted embolization. A1 aneurysms represent rare and difficult vascular lesions. EVT is quite challenging for A1 aneurysms due to their distinctive configurations. The outcomes are acceptable.

Management of Proximal Segment of the Anterior Cerebral Artery Aneurysms

ABSTRACT

The authors reported 2 cases with proximal anterior cerebral artery (A1) aneurysms, and one was treated with aneurysm clipping, whereas another was treated with coil embolization. The authors suggest both endovascular surgery and aneurysm clipping are good options for A1 aneurysms.

Contemporaneous Clipping of Unruptured Anterior Cerebral Artery Proximal A1 Segment Aneurysm and Resection of Dural-Based Brain Tumor

The coexistence of brain tumors and unruptured intracranial aneurysms is uncommon, so there is limited data regarding management strategies for these cases. Tumor, aneurysm, and patient factors must be considered in the decision-making process. We present a case of a dural-based left temporal brain tumor with an incidental ipsilateral unruptured anterior cerebral artery (ACA) proximal A1 segment aneurysm.

A 56-year-old female presented with progressive headaches and convulsions without focal neurological deficits. Neuroimaging showed a large dural-based left temporal tumor with adjacent vasogenic edema. The patient underwent a cerebral angiography for preoperative tumor embolization, which revealed a small, unruptured intracranial aneurysm arising from the left ACA proximal A1 segment. We performed a left frontotemporal craniotomy for concurrent resection of the dural-based tumor and clipping of the left A1 aneurysm. She elected to proceed, so she underwent a left-sided craniotomy for tumor resection and clipping of the aneurysm. Postoperatively, the patient developed transient, mild right-sided hemiparesis from a left anterior thalamic infarct that resolved before discharge. Follow-up brain magnetic resonance imaging and catheter cerebral angiography showed gross total resection of the tumor and complete aneurysm obliteration, respectively. Patients with dual diagnoses of a brain tumor and intracranial aneurysm can be challenging to manage. When intervention is indicated for each lesion and both can be safely accessed from the same operative approach, contemporaneous surgical treatment of the tumor and aneurysm is reasonable in appropriately selected cases.

Safety and efficacy of different therapeutic strategies in the endovascular treatment of anterior cerebral artery aneurysms with different features: A single centre experience

BACKGROUND

Outcomes of endovascular treatment of anterior cerebral artery (ACA) aneurysms are still not well-characterized.

OBJECTIVE

The study aimed to review the clinical effect, procedure-related complications and follow-up outcomes and to evaluate the safety and efficacy of endovascular treatment of ACA aneurysms in our center experience.

METHODS

From August 2014 to August 2018, a total of 75 consecutive patients with 77 ACA aneurysms were treated via the endovascular approach after providing informed consent. A retrospective review of the clinical, radiological, and endovascular details of these patients was conducted.

RESULTS

The mortality and the morbidity in this study were 4% and 9.3%, respectively. Compared with A1 and A2 aneurysms, intraoperative rupture was more common in A3 aneurysms (P = 0.029). Difference between the ruptured and unruptured aneurysms in the distribution of therapeutic strategy (P = 0.003) and immediate embolization degree (P = 0.004) was also significant. Statistical analysis demonstrated that the larger aneurysm (P = 0.031) was, the greater the ratio of aneurysm size to parent artery diameter (P = 0.029) was, the more likely the unruptured aneurysms were to occur ischemic events. Higher Hunt-Hess grade (P = 0.0066) was an independent risk factor for poor clinical outcome.

CONCLUSION

Endovascular treatment is feasible and effective for ACA aneurysms.

Radiological and clinical outcomes of endovascular coiling of proximal A1 aneurysms

Aneurysms of the proximal anterior cerebral artery (A1) are rare. Of these A1 aneurysms, proximal A1 aneurysms are among the most challenging for endovascular coiling. This study aimed to evaluate the angiographic features and radiological and clinical outcomes of endovascular coiling of proximal A1 aneurysms. We recruited 38 patients with 38 proximal A1 aneurysms treated with endovascular coiling between September 2005 and April 2016. Baseline patient characteristics, aneurysm morphology, endovascular treatment techniques, immediate post-procedural radiological outcome, and follow-up clinical and radiological outcomes were evaluated, as were risk factors for recurrence. Sixteen proximal A1 aneurysms ruptured (42.1%). Six procedural complications (15.8%), including 5 thromboembolisms and 1 coil migration, were noted. There was no procedural morbidity or mortality. Immediate post-procedural radiological outcomes showed complete occlusion in 23, residual necks in 12, and residual sacs in 3 lesions. Follow-up angiographic outcomes were possible for 28 lesions (73.7%). Follow-up angiography showed sac recurrence in 3 (10.7%) and neck recurrence in 3 (10.7%) lesions. Retreatment was performed in 4 lesions (14.3%); all were treated by endovascular coiling. The presence of aneurysmal ruptures was only significant regarding recurrence in univariate logistic regression analysis. In our study, endovascular coiling of proximal A1 aneurysms was associated with a relatively high rate of procedural complications but not with procedural morbidity and mortality. The recurrence and retreatment rates of endovascular coiling of proximal A1 aneurysms were relatively high, and presence of rupture was significant for recurrence.

Endovascular Treatment of Ruptured Proximal Segment of the Anterior Cerebral Artery Aneurysms: Single-Center Experience and Literature Review

BACKGROUND

Proximal anterior cerebral artery (A1) aneurysms are rare among all intracranial aneurysms and are regarded as difficult to treat endovascularly. Treatment is even more challenging in patients with ruptured aneurysms and acute subarachnoid hemorrhage owing to the small size and proximity to perforators. Though challenging, endovascular treatment can provide favorable outcomes in such patients. We report our case series of endovascular treatment in ruptured proximal A1 aneurysms.

METHODS

Between January 2010 and December 2017, 1200 aneurysms were treated endovascularly at our center. There were 15 patients with 15 ruptured proximal A1 aneurysms who presented with subarachnoid hemorrhage. Five patients underwent simple coiling, 9 underwent balloon-assisted coiling, and 1 underwent catheter protective coiling. Medical records and angiographic results were obtained retrospectively.

RESULTS

All aneurysms were successfully treated with endovascular techniques. Multiplicity rate was 53.3% (n = 8). Initial complete obliteration rate was 93.3% (n = 14), with a 13.3% recurrence rate (n = 2). One patient experienced intraoperative bleeding; this was the only procedure-related complication. Eleven patients (73.3%) had a good clinical outcome. When excluding Hunt and Hess grade 4 patients, the good outcome rate was 81.8%.

CONCLUSIONS

Ruptured proximal A1 aneurysm is a rare condition and is highly associated with multiple aneurysms. Despite being a more difficult and complicated technique, endovascular coiling performed in high-volume, experienced medical centers is an effective modality with excellent clinical outcomes.

Aneurysms of the Proximal (A1) Segment of the Anterior Cerebral Artery: A Clinical Analysis of 31 Cases

OBJECTIVE

This study aimed to investigate the characteristics of A1 aneurysms according to their locations and to compare their imaging appearances so as to identify factors associated with their rupture.

METHODS

We retrospectively reviewed the medical records of 31 patients harboring 32 A1 aneurysms diagnosed and treated between March 2009 and September 2018 at our institute.

RESULTS

Thirteen (41.9%) of the patients had vascular abnormalities, and multiple aneurysms were found in 13 (41.9%) patients. A total of 16 (53.3%) aneurysms were located on the proximal A1 segment, whereas the middle segments were affected in 7 (23.3%) and the distal segments in 7 (23.3%). Altogether, 93.8% of proximal A1 aneurysms projected posteriorly, 85.7% of middle aneurysms projected superiorly, and 85.7% of distal aneurysms projected inferiorly (P = 0.000). Four (33.3%) of the 12 total ruptured aneurysms were located on the distal A1 segment. Nine (69.2%) ruptured aneurysms were elongated or irregular in shape (P = 0.004). The aspect and height-width ratios of the ruptured aneurysms were higher than those of the unruptured aneurysms (P = 0.001, P = 0.018, respectively).

CONCLUSIONS

Most A1 aneurysms showed a directional predilection according to the location of the A1 segment. Additionally, A1 aneurysms with elongated or irregular shapes, high aspect or height-width ratios, and distal locations of the A1 segment showed high risks of rupture. Therefore, a thorough assessment of the characteristics of A1 aneurysms can enhance the selection of proper treatment strategies.

Characteristics of Peri-Internal Carotid Artery Bifurcation Aneurysms According to a New Anatomic Classification: How to Overcome Difficulties in the Microsurgical Treatment of Posteroinferiorly Projecting Carotid-A1 Junctional Aneurysms

OBJECTIVE

Based on our clinical experience, posteroinferiorly projecting carotid-A1 junctional aneurysms are often difficult to treat microsurgically. Our objective was to classify peri-internal carotid artery (ICA) bifurcation aneurysms according to their location and analyze their characteristics.

METHODS

From January 2008 to October 2017, microsurgical or endovascular treatment of 6777 aneurysms were performed at our hospital. We identified 199 peri-ICA bifurcation aneurysms (2.94%) classified into true ICA bifurcation aneurysm, carotid-A1 junctional aneurysm, and carotid-M1 junctional aneurysm according to the anatomic location. Medical records including patient characteristics, aneurysm location, surgical method, any neurologic deficits, clinical outcomes, medical history, and radiologic findings were retrospectively reviewed. The anatomic position of the aneurysm was defined from the virtual surgical, anteroposterior, and lateral views, and the degree of agreement was calculated.

RESULTS

There were 103 true ICA bifurcation aneurysms, 92 carotid-A1 junctional aneurysms, and 4 carotid-M1 junctional aneurysms. Carotid-A1 junctional aneurysms tended to be smaller, elongated, and more often posteroinferiorly projecting than true ICA bifurcation aneurysms. Posteroinferiorly projecting carotid-A1 junctional aneurysms tended to require complex aneurysm surgery. The virtual surgical view had an almost perfect degree of agreement with the actual surgical view.

CONCLUSIONS

The characteristics of carotid-A1 junctional aneurysms and true ICA bifurcation aneurysms differ. In particular, carotid-A1 junctional aneurysms tend to have a posteroinferior projection and that causes difficulty in surgical treatment. We recommend the virtual surgical view for preoperative planning. Furthermore, an adequate Sylvian fissure opening and a strategic approach using appropriate devices to inspect blind spots should be considered for a successful treatment outcome.

Flow diversion covering the M1 origin as a last resort

Introduction

Internal carotid artery termination (ICAT) and proximal A1 aneurysms can be challenging for open surgical clipping or endovascular coiling. Treatment with flow diversion covering the middle cerebral artery (MCA), an end vessel supplying a terminal circulation, has not been reported.

Methods

A prospective, Institutional Review Board-approved database was analysed for patients with pipeline embolisation device (PED) placement from the anterior cerebral artery (ACA) to the ICA during cerebral aneurysm treatment.

Results

Nine cases were identified, including five proximal A1, three posterior communicating artery and one ICAT aneurysm locations. Average aneurysm size was 8.3 mm (range 3-17), with 67% saccular and 78% right-sided. Primary indication for treatment was significant dome irregularity (44%), recurrence or enlargement (33%), underlying collagen vascular disorder (11%) and traumatic pseudoaneurysm (11%). Preservation of the ipsilateral ACA (with PED placed in A1) was performed when the anterior communicating artery (67%) or contralateral A1 (33%) were absent on angiography. Adjunctive coiling was done in four cases (44%). There was one major stroke leading to mortality (11%) and one minor stroke (11%). Clinical follow-up was 27 months on average. Follow-up digital subtraction angiography (average interval 15 months) showed complete aneurysm obliteration (88%) or dome occlusion with entry remnant (12%). The jailed MCA showed minimal or mild delay (primarily anterograde flow) in 75% of cases and significant delay (reliance primarily on ACA and external carotid artery collaterals) in 25%.

Conclusions

Covering the MCA with a flow diverting stent should be reserved for select rare cases. Strict attention to blood pressure augmentation during the periprocedural period is necessary to minimise potential ischaemic compromise.

Contralateral Approach to Coil Embolization of Proximal A1 Aneurysms Using the Anterior Communicating Artery

BACKGROUND AND PURPOSE

Aneurysms arising from the proximal A1 segment of the anterior cerebral artery are rare, and their distinctive configurations often pose technical challenges during endovascular embolization. Herein, we present 11 patients with proximal A1 aneurysms requiring a contralateral approach (via the anterior communicating artery) to coil embolization.

MATERIALS AND METHODS

From a prospectively collected data repository, we retrieved records of 11 patients consecutively treated for proximal A1 aneurysms between January 2011 and March 2018. In each instance, coil embolization was performed by the contralateral route. Outcomes were analyzed in terms of morphologic features and clinical status.

RESULTS

Aneurysms in all 11 patients were directed posteriorly and were small (<5 mm). A contralateral approach (via the anterior communicating artery) was used after ipsilateral attempts at aneurysm selection failed in each instance, despite using a variety of microcatheters. Single punctures and single guiding catheters sufficed in 9 patients, but 2 patients required dual punctures and 2 guiding catheters. All endovascular treatments ultimately yielded excellent outcomes. Although 1 symptomatic infarct was manifested in the course of ipsilateral treatment, no morbidity or mortality resulted from the contralateral access.

CONCLUSIONS

Due to angio-anatomic constraints, a contralateral strategy for coil embolization of proximal A1 aneurysms is acceptable if ipsilateral access is technically prohibitive and the vessels (contralateral A1 and anterior communicating artery) are amenable to the passage of microdevices.

Radiographic and microsurgical characteristics of proximal (A1) segment aneurysms of the anterior cerebral artery

BACKGROUND

Proximal A1 segment aneurysms of the anterior cerebral artery (ACA) radiologically resemble internal carotid artery bifurcation (ICBIF) aneurysms because of their anatomical proximity. However, proximal A1 aneurysms exhibit distinguishing features, relative to ICBIF aneurysms. We report our experience of managing proximal A1 aneurysms, then compare them to ICBIF aneurysms.

METHODS

Among 2191 aneurysms treated between 2000 and 2016 in a single institution, we retrospectively reviewed 100 cases categorized as ICBIF or A1 aneurysms. We included aneurysms originating from the ICBIF and ACA, proximal to the anterior communicating artery (A1 segment) and divided them into two groups: proximal A1 (n = 32) and ICBIF (n = 50). If any portion of the aneurysm involved the ICBIF, it was classified as ICBIF. Aneurysms wholly located in the A1 segment were classified as proximal A1. Patient factors and angiographic factors were evaluated and compared.

RESULTS

The proximal A1 group exhibited differences in aneurysm size (p = 0.013), posterior aneurysm direction (p = 0.001), and A1 perforators as incorporating vessels (p = 0.001). The proximal A1 group tended to rupture more frequently when the aneurysm was smaller (p = 0.046). One case of morbidity occurred in the proximal A1 group.

CONCLUSION

Compared to ICBIF aneurysms, proximal A1 aneurysms were smaller and directed posteriorly, with incorporating perforators. Because of these characteristics, it may be difficult to perform clipping with 360° view in microsurgical field. Therefore, when planning to treat proximal A1 aneurysms, different treatment strategies may be necessary, relative to those used for ICBIF aneurysms.

Aneurysms of the Proximal Segment of the Anterior Cerebral Artery: A New Classification System with Corresponding Therapeutic Options

OBJECTIVE

This study aims to establish a new classification system for proximal anterior cerebral artery (A1) aneurysms and to offer treatment strategies, based on the lessons learned by studying the case reports of 41 patients with A1 aneurysms.

METHODS

A total of 2332 consecutive patients with intracranial aneurysms were treated at a single medical center between June 2005 and May 2015. Forty-one patients with 42 A1 aneurysms were treated by surgical clipping or endovascular coiling. Clinical data, radiographic results, treatments, and patient outcomes were later collected and analyzed.

RESULTS

Of 2332 intracranial aneurysm patients, 1.76% (n = 41) had a total of 42 A1 aneurysms. Twenty-six of these (62%) were proximal A1 segment aneurysms, 9 (21%) were distal A1 segment aneurysms, and 7 (17%) were fusiform A1 aneurysms. A1 aneurysms can be classified into 3 main types. Types IA and IB originate from the posterior wall of the proximal A1 segment. Type IA projects posterior-inferiorly, whereas type IB projects posterior-superiorly. Type IIA originates from the distal trunk of the A1 artery. Type IIB originates from an angle of an abnormal cortical branch or a ring of an A1 arterial fenestration. Type III consists of fusiform or dissecting aneurysms located anywhere along the A1 segment. After studying the range of treatments and outcomes, when treating these complex morphologies, we recommend clipping type I and II A1 aneurysms and embolizing type III A1 aneurysms.

CONCLUSIONS

A1 artery aneurysms are a rare type of aneurysm with unique characteristics. The classification system proposed here accurately summarizes these characteristics to better guide treatment strategies.

Angiographic Characteristics and Endovascular Treatment of Anterior Cerebral Artery A1 Segment Aneurysms

OBJECTIVE

This report aimed to review the angiographic characteristics and evaluate the safety and feasibility of endovascular treatment of A1 aneurysms.

METHODS

Nineteen ruptured and 13 unruptured A1 aneurysms treated endovascularly were evaluated in this study. The angiographic and clinical records were retrospectively reviewed.

RESULTS

Endovascular treatments were successfully applied in all 32 aneurysms. Conventional coiling was performed in 24 aneurysms, stent-assisted coiling in 7, and solo stenting in 1. The immediate angiographic result was 1 aneurysm in 15, two aneurysms in 10, and 3 in 7 aneurysms according to the Raymond grade. Intraoperative rupture was detected in 1 case without clinical consequence, and no other procedure-related complication occurred. Angiographic follow-up (mean, 12 months; range, 2-42 months) of 25 aneurysms showed total occlusion in 20, improvement in 1, stability in 3, and recurrence in 1. The only recurrence was detected in a case treated using conventional coiling, and it was retreated with stent-assisted coiling. Clinical follow-up (mean, 25 months; range, 6-93 months) was available in 24 of 30 patients, and the modified Rankin Scale score was 0-1 in 22 patients.

CONCLUSIONS

Endovascular treatment is technically feasible and safe for A1 aneurysms.