Endovascular treatment of aneurysms arising from the proximal segment of the 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.

Application of Computational Fluid Dynamic Simulation of Parent Blood Flow in the Embolization of Unruptured A1 Aneurysms

OBJECTIVE

To investigate the effect of microcatheter shaping based on the parent artery mainstream line of blood flow simulated using the computational fluid dynamics (CFD) technique on embolization of unruptured aneurysms on the posterior wall of the anterior cerebral artery (ACA) A1 segment.

METHODS

Patients with unruptured cerebral aneurysms on the posterior wall of the ACA A1 segment were retrospectively enrolled and treated with endovascular embolization after microcatheter shaping. The clinical, embolization, and follow-up data were analyzed.

RESULTS

Eight patients were enrolled and treated with endovascular embolization. 8 microcatheters were steam-shaped in vitro and were all successfully navigated to the right location in the in vitro experiment. During the embolization procedure, 7 microcatheters were successfully navigated to the right location for embolization. In the remaining 1 patient who had tortuous cerebral arteries, reshaping of the microcatheter based on the parent artery mainstream of blood flow made successful navigation of the microcatheter to the right place. Complete occlusion was obtained in 7 (87.5%) aneurysms and residual aneurysm neck in the remaining 1 (12.5%). At angiographic follow-up in 6 (75%) patients, the Raymond grade was I in 5 (83.3%) and II in the rest 1 (16.7%).

CONCLUSIONS

Use of computational fluid dynamics simulation of parent artery blood flow for microcatheter shaping in the embolization of unruptured aneurysms on the posterior wall of the ACA A1 segment is safe and effective in navigating the microcatheter to the right location for embolization, resulting in good stability and support for the embolization.

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.

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.

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.

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.

Microcatheter shaping using three-dimensional printed models for intracranial aneurysm coiling

Background and purpose

Microcatheterization is an important, but also difficult, technique used for the embolization of intracranial aneurysms. The purpose of this study was to investigate the application of three-dimensional (3D) printing technology in microcatheter shaping.

Methods

Nine cases of internal carotid artery posterior communicating artery aneurysm diagnosed by CT angiography were selected, and 3D printing technology was used to build a 3D model including the aneurysm and the parent artery. The hollow and translucent model had certain flexibility; it was immersed in water and the microcatheter was introduced into the water to the target position in the aneurysm, followed by heating the water temperature to 50°C. After soaking for 5 min, the microcatheter was taken out and the shaping was completed. After sterilization, the shaped microcatheter was used for arterial aneurysm embolization and evaluation was conducted.

Results

Nine cases of microcatheter shaping were satisfactory and shaping the needle was not necessary; no rebound was observed. The microcatheter was placed in an ideal position, and the stent-assisted method was used in three cases of wide-neck aneurysm. There were no complications related to surgery.

Conclusion

A new microcatheter shaping method using 3D printing technology makes intracranial artery aneurysm embolization more stable and efficient.

The Special Considerations in the Surgical Management of Proximal Anterior Cerebral Artery Aneurysms

BACKGROUND

Proximal anterior cerebral artery (A1) aneurysms are difficult to clip because of their frequent proximity to perforators, location behind the parent artery, or adherence to surrounding structures.

METHODS

We retrospectively reviewed a consecutive series of patients with A1 aneurysms and report the clinical status, radiologic findings, treatment methods, and outcome.

RESULTS

This series included 19 male and 12 female patients with a mean age of 50 years. The morphology of the A1 aneurysms was fusiform in 2 patients and saccular in the remaining 29 patients. Multiple aneurysms were presented in 9 patients (29.0%). On admission, 26 patients (83.9%) presented with subarachnoid hemorrhage, 3 of whom had an additional intracerebral hematoma. All surgeries were performed with a standard pteriomal craniotomy. The mean Glasgow Outcome Scale score at final follow-up was 4.8 (interquartile range, 5, 5), with 26 patients (83.9%) rated as 5. The mean follow-up time was 38.5 months (range, 12-60 months).

CONCLUSIONS

A1 aneurysms are rare but have their own complex characteristics and are difficult to treat. Meticulous analysis of the relevant angiographs is needed for their diagnosis. An important consideration in surgery is the preservation of perforators and prevention of rupture. Wide opening of the sylvian fissure and temporary control of the parent artery can facilitate dissection of the A1 aneurysms dome. Multiple intraoperative monitoring methods, such as microvascular Doppler ultrasonography and somatosensory and motor evoked potential monitoring, can reduce the relevant complications of surgery.

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.

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.