Double stent-assisted coiling with Neuroform Atlas stents for treating ruptured blood blister-like aneurysms

Hyoung Bin Kim; Lee Hwangbo; Young Ha Kim; Pil Soo Kim; Jun Kyeung Ko

doi:10.7461/jcen.2025.E2025.05.003

J Cerebrovasc Endovasc Neurosurg > Volume 27(4); 2025 > Article

Kim, Hwangbo, Kim, Kim, and Ko: Double stent-assisted coiling with Neuroform Atlas stents for treating ruptured blood blister-like aneurysms

Clinical Article

Journal of Cerebrovascular and Endovascular Neurosurgery 2025;27(4):327-337.

Published online: July 23, 2025

DOI: https://doi.org/10.7461/jcen.2025.E2025.05.003

Double stent-assisted coiling with Neuroform Atlas stents for treating ruptured blood blister-like aneurysms

Hyoung Bin Kim^1,^3,⁴, Lee Hwangbo^2,^3,⁴, Young Ha Kim^1,^3,⁴, Pil Soo Kim^1,^3,⁴, Jun Kyeung Ko^1,^3,⁴

¹Department of Neurosurgery, Pusan National University Hospital, Busan, Korea

²Department of Diagnostic Radiology, Pusan National University Hospital, Busan, Korea

³Biomedical Research Institute, Pusan National University Hospital, Busan, Korea

⁴School of Medicine, Pusan National University, Busan, Korea

Correspondence to Jun Kyeung Ko Department of Neurosurgery, Pusan National University Hospital, 179 Gudeok-ro, Seo-gu, Busan 49241, Korea Tel +82-51-240-7257 Fax +82-51-244-0282 E-mail redcheek09@naver.com

Received May 13, 2025 Revised July 6, 2025 Accepted July 13, 2025

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Objective

A ruptured blood blister-like aneurysm (BBA) of the supraclinoid internal carotid artery is a rare but surgically challenging vascular disease. Numerous endovascular approaches have been reported, but optimal management remains controversial. This study aimed to report on our experience and assess the safety and efficacy of our treatment strategy.

Methods

The treatment strategy basically involves stent-assisted coiling using semi-jailing technique followed by stent overlap with Neuroform Atlas stents. Angiographic results (modified Raymond scale), clinical outcomes (modified Rankin Scale), and technical feasibility were evaluated.

Results

A total of ten patients with ruptured BBAs were treated via this technique (8 women; mean age, 45.4 years). Procedures were successfully applied without any procedure-related symptomatic complications except one thromboembolism. The immediate angiographic results were complete occlusion in 6 aneurysms, residual neck in 1 aneurysm, and residual sac in 3 aneurysms. Early complementary treatment was required in one. Follow-up angiograms (mean, 9.6 months), which were available in 8 patients, showed complete resolution of BBAs in all, except one who was retreated with a flow diverter. At the end of the observation period (mean, 41.0 months), all patients had excellent clinical outcomes (modified Rankin Scale 0-1), except two with initial poor grade subarachnoid hemorrhage.

Conclusions

Double stent-assisted coiling using Neuroform Atlas stents offers a feasible and practical reconstructive option for ruptured BBAs, particularly in healthcare systems where flow diverters are not approved for acute-phase use.

Keywords: Endovascular procedure, Intracranial aneurysm, Internal carotid artery, Stents

INTRODUCTION

Despite advances in endovascular and microsurgical techniques, blood blister-like aneurysms (BBAs) frequently present a tremendous therapeutic challenge due to their unfavorable morphology and histology [9,15]. Although the efficacy of microsurgical treatment of BBA has been demonstrated, the endovascular intervention has gradually become the preferred alternative for BBA treatment, owing to its lower complication rate and better prognosis [10,13,14,17]. Numerous interventional techniques in the treatment of BBA, including stenting with or without coiling, endovascular trapping, and a combination of other procedures, have been suggested to treat BBAs, but a standard protocol has not yet been established [12,17]. Recently, more reports have focused on the invention of the flow diverter (FD) for BBA treatment [14,21]. However, the flow diverters also have critical issues of a low initial occlusion rate and early rebleeding [21]. In our country, FD is currently allowed for limited indications. FD is not allowed for treating ruptured aneurysms.

In the present series, to achieve complete aneurysm exclusion and parent artery preservation, we attempted to treat ruptured BBAs with double stent-assisted coiling (SAC) using Neuroform Atlas stents (NASs) (Stryker Neurovascular, Kalamazoo, MI, USA). Our aim was to evaluate the efficacy of double SAC using NASs for the endovascular reconstructive treatment of ruptured BBAs by reviewing patients’ clinical and radiological data.

MATERIALS AND METHODS

The study was approved by the Research Ethics Board of our institution (IRB number 2310-007-131).

Study population

We performed a review of the clinical and radiological records of all patients between March 2018 and September 2023, in a prospective registry of patients who underwent double SAC using NASs for treating ruptured BBAs. Double SAC using NASs was attempted in almost all ruptured BBAs that were expected to be difficult to treat using conventional surgical or endovascular techniques. Digital subtraction angiography (DSA) was used to diagnose ruptured BBAs. BBAs were diagnosed using the following criteria: (1) the aneurysm was located at a non-branching segment of the supraclinoid internal carotid artery (ICA), and (2) there was evidence of morphological change over time, such as size enlargement or contour evolution, confirmed by serial DSA performed within one week. These lesions typically lacked a clearly defined neck and appeared as hemispherical bulges arising directly from the arterial wall. Exclusion criteria were the following: (1) BBAs in location other than supraclinoid ICA (i.e., basilar artery and anterior cerebral artery) and (2) other endovascular techniques performed (i.e., internal trapping and multiple overlapping stents without coiling). During this study, no other type of stent other than NAS was actually used for the treatment of ruptured BBAs in our institution.

General information on endovascular treatment

In general, endovascular treatment was administered as soon as possible after subarachnoid hemorrhage (SAH), regardless of the clinical condition of the patient. All procedures were performed via the unilateral or bilateral transfemoral approach under intravenous sedation with full anticoagulation using intravenous heparin. The activated clotting time was maintained at two to three times the baseline measurement throughout the procedure. All patients received subcutaneous administration of 2850 IU of low-molecular heparin (Fraxiparin, GlaxoSmithKline, Marly-le-Roi Cedex, France) twice or three times per day, for a duration of three days postoperatively, according to our protocol of SAC. Antiplatelet premedication was not given, but a loading dose of dual antiplatelet medication (clopidogrel 300 mg and acetylsalicylic acid 300 mg) was administered immediately after the procedure. Dual-antiplatelet drugs, which consisted of clopidogrel (75 mg) and acetylsalicylic acid (100 mg) each day, were also maintained for at least six months. A clopidogrel resistance test was performed approximately 24 hours after drug administration. In patients who were poor responders to clopidogrel, as indicated by the VerifyNow P2Y12 assay, cilostazol was added to the treatment regimen.

Double stent-assisted coiling using Neuroform Atlas stents

This treatment basically consisted of the following two steps: first, SAC using semi-jailing technique is performed, followed by stent overlap. A 6- or 7-Fr Shuttle guiding catheter (Cook Medical, Bloomington, IN, USA) was placed at the cervical ICA. The distal-access intermediate catheter was positioned in the petrous ICA for coaxial guiding. Cerebral angiography with three-dimensional rotational angiography was performed to determine the orientation, neck width, rupture point, and working view of the BBAs. Since 2018, when NAS was introduced in our country, it has been preferred for SAC of most aneurysms in our institution. A 0.017-inch microcatheter (Echelon, EV3, Irvine, CA, USA) for stent delivery was navigated beyond the BBA neck over a microwire to the M1 segment. The NAS was then advanced through the catheter and readied for deployment. A second microcatheter for coil delivery was then carefully placed into the BBA sac using a guidewire, and one or two loops of the first coil were deployed. The stent was partially deployed, approximately one-third, to reduce the effective neck size and to prevent distal coil migration. Because the microcatheter for coil delivery is not constrained by the stent, it remains freely maneuverable during the procedure and permits the passive kick-back movement of the microcatheter while decreasing the risk of aneurysm perforation during coil packing. Soft and short coils were selected and carefully inserted into the fragile BBA. The stent was then fully deployed to bridge the aneurysm neck when the dense coil packing was achieved or the coil herniation persisted. After the first stent deployment, the stent delivery microcatheter was re-advanced to the initial position over the stent-loading wire. A second stent was then introduced and partially deployed, overlapping the first stent in the funnel shape as described for the first stent. Coil embolization was then performed as compactly as possible with gradual stent deployment. The procedure is shown in Fig. 1.

Analysis

Angiographic follow-up was typically performed at 1-2 weeks and 6 months postoperatively if the postoperative course was uneventful. Retreatment was usually performed for recurrent BBA at the same session. Angiographic results were categorized as the modified Raymond classification. Radiological data included geometrical measurements of the aneurysms, recurrence, and Raymond classification scale of the last follow-up DSA. Radiologic assessments were conducted by the author (J.K.K.) with 15 years of experience in neurointervention. Procedural data included the periprocedural thromboembolic or hemorrhagic complications. Clinical results were assessed upon discharge from the hospital and at the last clinical visit, using the modified Rankin Scale (mRS).

RESULTS

Patient population and aneurysm morphology

Patient demographic data and characteristics of aneurysms are provided in Table 1. This study involved 10 patients (8 women and 2 men) who had acute SAH due to BBA rupture. The mean age of the patients was 45.4 years (range, 34 to 64 years). The initial Hunt-Hess grade was II in six (60%) patients, III in two (20%) patients, and IV in two (20%) patients. The modified Fischer computed tomography grade was I in three (30%) patients, II in one (10%), III in five (50%) patients, and IV in one (10%) patient. External ventricular drainage was placed in one patient immediately after the procedure. Of the patients, eight (80%) were treated in the first 24 h after the ictus, and two (20%) were treated in the 24- to 72-h period. The average duration from disease onset to treatment was 1.3 days (range, 1-3 days). All BBAs were located at the supraclinoid ICA. All aneurysms were wide-necked with an average neck diameter of 3.17 mm (range, 1.9-4.2) and depth of 2.5 mm (range, 1.6-3.4).

Periprocedural complications

Periprocedural complications and results of treatment are shown in Table 2. Double SAC using NASs was technically successful in all ruptured BBAs. No cases of rebleeding or rerupture occurred during the procedure. Overall, periprocedural complications occurred in six (60%) patients: asymptomatic acute in-stent thrombosis in four (40%), asymptomatic aneurysm recurrence in one (10%), and symptomatic thromboembolic complications in one (10%). Therefore, one (10%) out of 10 patients experienced symptomatic periprocedural complications in this study. Four patients with acute in-stent thrombosis underwent intraarterial thrombolysis with a total amount of 1 mg of abciximab injection intra-arterially, and experienced successful recanalization without any symptoms (Fig. 2). Early follow-up DSA (mean, 6.4 days) was performed in 8 patients within 2 weeks after the procedure, and confirmed one case of recurrence including morphological change and enlargement of the lesion. Retreatment was performed at seven days and involved two additional NSAs placements without coiling. The lesion was confirmed to be completely occluded by 18-month follow-up DSA (Patient 7). In patient 5, she complained of left leg weakness on the 7^th day after procedure. An immediate magnetic resonance imaging showed acute cerebral infarction in the territory of the stented artery. Nonetheless, she was significantly improved to an mRS of 1 by six months. Thus, the periprocedural mortality in our cohort was 0% and morbidity was 10% (1 of 10 procedures).

Clinical and radiological outcomes

Immediate post-procedural angiograms showed complete occlusion in 6 aneurysms (60%), neck remnant in 1 aneurysm (10%), and aneurysm remnant in 3 aneurysms (30%). DSA follow-up was obtained in 8 out of 10 aneurysms at intervals ranging from 4 to 24 months (mean, 9.6 months), and showed complete resolution of BBAs except one. Parent arteries with stenting were patent with no evidence of definite intimal hyperplasia or in-stent stenosis in all cases. In patient 2, 11-month follow-up DSA showed that the BBA had recurred, and the coils were compressed and displaced. Recurrent aneurysm was uneventfully treated with an FD (Fig. 3). Two patients were discharged with an mRS score of 5-6 as a direct consequence of the initial SAH. The remaining 8 patients had excellent clinical outcomes (mRS 0-1) without rebleeding during the follow-up period of 18 to 90 months (mean, 41.0 months).

DISCUSSION

The present study demonstrates that Double SAC with NASs is a feasible and effective approach for treating ruptured BBAs of the supraclinoid ICA. Despite the small sample size, our findings indicate that this endovascular technique offers favorable angiographic and clinical outcomes with a relatively low rate of symptomatic complications.

BBAs are fragile, thin-walled aneurysms that pose significant treatment challenges due to their rapid morphological changes and high risk of rebleeding [9,15]. While microsurgical clipping has traditionally been used, endovascular treatment has gained popularity due to its less invasive nature. Several endovascular techniques have been proposed for BBA treatment, including simple coiling, SAC, flow diversion, and vessel occlusion [10,12,13,17]. However, each technique has its limitations. Simple coiling is often inadequate due to the wide-necked or nonexistent neck of BBAs. SAC provides a scaffold for coil embolization while preserving the parent artery. In this study, double SAC with NASs was employed to enhance the stability of the coil mass and promote aneurysm occlusion. The overlapping stents provide additional support to the fragile aneurysm wall and promote endothelialization. To treat ruptured BBAs in the acute stage, it is critical to block blood flow from the affected wall to prevent rebleeding and regrowth. Stent porosity is strongly correlated with hemodynamic changes, and an animal study confirmed that a higher metal coverage rate is positively associated with improved angiographic and clinical outcomes [13]. Overlapping stents may divert more blood flow from the affected segment than a single stent by decreasing stent porosity, further straightening the parent vessel, and increasing stent thickness. Greater strut density and thickness facilitate neointima formation [8]. Therefore, multiple stents not only provide immediate protection against hemorrhage by redirecting flow, disrupting intra-aneurysmal circulation, and dispersing the inflow jet, but also enhance angiographic outcomes and improve the long-term durability of coils by promoting further stent endothelialization and intravascular remodeling [5]. A proportion meta-analysis compared angiographic outcomes between single and multiple SACs in BBA treatment [12]. The study found that the complete occlusion rate was higher in the group with two or more stents (80.39%) compared to the single stent group (48.10%). Additionally, the recurrence rate was lower in the multiple stents group (14.29%) than in the single stent group (25.32%). These findings suggest that using multiple stents in SAC may lead to better angiographic outcomes. Several studies have investigated the use of multiple (three or more) overlapping stents combined with coiling for treating ruptured BBAs [10,18]. These studies suggest that multiple overlapping stents with coiling can be a feasible alternative for treating ruptured BBAs. Although overlapping stents may modify intra-aneurysmal flow by reducing overall porosity, we acknowledge that NASs are not designed as flow diverters and do not replicate the flow-diverting characteristics of dedicated FD devices. In this study, the suggestion of hemodynamic benefit remains hypothetical and is not supported by computational fluid dynamics or direct hemodynamic measurements. Therefore, any potential flow-disrupting effect should be interpreted with caution.

FD devices have emerged as a significant advancement in the endovascular treatment of intracranial aneurysms, including BBAs. Their unique mechanism focuses on reconstructing the parent artery and promoting aneurysm thrombosis by diverting blood flow away from the aneurysm sac. FDs have demonstrated substantial efficacy in achieving complete aneurysm occlusion. In a study involving 30 patients with ruptured BBAs treated with the Flow-Redirection Endoluminal Device (FRED), complete obliteration was achieved in 80% of patients at six months and 92% at a median follow-up of 22 months [2,14]. The structural design of FDs contributes to the long-term stability of aneurysm occlusion, reducing the likelihood of recanalization. A meta-analysis reported a complete occlusion rate of 72% for BBAs treated with FDs, indicating durable outcomes [21]. However, the use of FDs is associated with certain risks. In the aforementioned study with the FRED device, major stroke or death occurred in 17% of patients [14,21]. Immediate complete occlusion is not always achieved with FDs. In the same study, only 33% of patients had immediate complete aneurysm obliteration post-procedure, with others requiring extended periods to reach full occlusion [14]. Patients undergoing FD treatment need prolonged dual antiplatelet therapy to prevent thromboembolic events, which can complicate management, especially in cases of ruptured aneurysms where there is a risk of hemorrhagic complications. Therefore, further studies are needed to evaluate the safety and effectiveness of FD treatment for BBAs. A proportion meta-analysis compared SAC with FD in managing BBAs. The long-term complete occlusion rate was higher in the FD group (89.26%) than in the SAC group (70.26%). Additionally, the aneurysm recanalization rate was lower in the FD group (4.54%) versus the SAC group (25.38%). However, rates of mortality, favorable functional outcomes, procedural complications, and rebleeding showed no significant differences between the two procedures. These results indicate that while FD may offer more favorable angiographic outcomes, SAC remains a viable option, especially when considering individual patient factors [12]. In our country, the use of FD is not currently permitted for ruptured aneurysms, including BBAs, but is allowed for BBAs that recur after the acute phase. Therefore, in accordance with current insurance policies, we prioritize double SAC for ruptured BBAs and apply FD treatment for BBAs that recur during follow-up after the acute phase. In this study, using double SAC with easy-to-handle NASs, coils could be safely placed using the jailing technique and/or semi-jailing technique or through a stent strut within the fragile aneurysm wall. As a result, no reruptures of BBAs occurred during or after the procedure. Additionally, the deployment of NASs was technically easier than that of FDs, allowing for more accurate stent placement at the intended location.

In this study, we exclusively used NASs due to their superior deliverability and procedural flexibility, especially in the tortuous anatomy of ruptured BBAs. Compared to LVIS (Low-profile Visualized Intraluminal Support) stents, which require a larger microcatheter and limit coiling techniques, NASs allow for easier navigation and enable coiling through the stent struts or via semi-jailing. Although LVIS is available for use in ruptured aneurysms in our country, our institutional preference for NASs reflects their practical advantages in achieving safe and effective double SAC, despite the limitation of being non-retrievable once partially deployed.

Based on our experience, double SAC using NASs is particularly suitable in the following indications: (1) ruptured BBAs at the non-branching site of the supraclinoid ICA, (2) wide-neck morphology with shallow sac depth, (3) poor response to conventional SAC or coil instability after initial embolization, and (4) contraindications to FD due to local regulations or bleeding risks.

Periprocedural complication rates in our study were comparable to or lower than those reported for other endovascular techniques. Asymptomatic in-stent thrombosis occurred in 40% of cases, but all were successfully managed with intra-arterial thrombolysis without clinical deterioration. Only one patient (10%) experienced symptomatic thromboembolic events, which occurred seven days after the procedure and improved significantly over time. Prior SAC series have indicated that thromboembolism rates are approximately 4-8% [4,6]. In a series of 19 cases of Y-SAC reported by Spiotta and colleagues, intraprocedural thromboembolism occurred in 3 cases (16%), while delayed thromboembolism was observed in 2 cases (11%) [19]. They reported that the Y-stent design, which involved two overlapping stents in the distal basilar artery—one telescoped over the other—along with additional intraluminal “hardware” (stent overlap), was less amenable to endothelialization without the scaffolding provided by adjacent intima. However, overlapping stenting in a telescoping fashion, as used in this study, does not interfere with the main blood flow, unlike Y- or X-stenting in a crossing fashion. Thus, the risk of thromboembolism is expected to be lower. The author of the present study previously proposed endovascular reconstruction using a filland-tunnel technique, a type of multiple overlapping stenting, for fusiform vertebral artery dissecting aneurysms with ipsilateral dominance, reporting excellent outcomes [11]. Additionally, he documented 23 cases of rescue stenting with NASs during stent-assisted coiling of saccular aneurysms, demonstrating favorable clinical and angiographic outcomes [3]. No intraoperative ruptures or periprocedural rebleeding events were observed, highlighting the technical safety of the procedure when performed under careful anticoagulation management. All but two patients with poor-grade SAH achieved favorable clinical outcomes (mRS 0-1) at a mean follow-up of 41.0 months, indicating that double SAC with NASs can lead to good long-term functional results. Our study showed a high rate of technical success with double SAC using NASs. Immediate angiographic results demonstrated complete occlusion in 60% of aneurysms, with progressive occlusion observed during follow-up. The use of double SAC with NASs allowed for both immediate aneurysm protection and vessel reconstruction. Additionally, stent overlap reinforced the aneurysm neck, promoting long-term occlusion and parent artery preservation. Our results showed a high rate of complete aneurysm occlusion at follow-up, with only one patient requiring retreatment with FD due to recurrence. These findings align with previous reports suggesting that NASs, with their open-cell design and improved conformability, contribute to enhanced vessel wall reconstruction and aneurysm stability [7]. Although various types of stents have been used in previous studies on BBA treatment, the present study is notable for achieving favorable treatment outcomes using only two NASs within a consistent treatment strategy, despite its retrospective design.

Thromboembolic complications are a significant concern in SAC for the treatment of SAH. Managing these complications and determining the optimal antiplatelet therapy to prevent them are key considerations in treating patients with ruptured intracranial aneurysms. The use of antiplatelet therapy in SAH patients undergoing SAC must balance the risk of thromboembolic events with the potential for bleeding complications. A DELPHI consensus among neurointerventional experts suggests a periprocedural dual-antiplatelet regimen, typically involving intravenous aspirin and a glycoprotein IIb/IIIa inhibitor, followed by a transition to oral antiplatelet agents within 24 hours post-procedure [16]. This approach aims to mitigate the risks associated with antiplatelet therapy in the acute setting of SAH. Multiple SAC carries a higher risk of thromboembolic complications compared to single SAC; however, this difference may be mitigated when adjusting for aneurysm characteristics. Despite the higher complication rates, the overall morbidity and mortality associated with SAC for ruptured aneurysms may be lower than expected [1,20]. While multiple SAC for ruptured aneurysms presents inherent risks, appropriate antiplatelet management can help reduce thromboembolic complications. The optimal antiplatelet regimen remains an active area of research, with recent evidence suggesting that shorter dual antiplatelet treatment durations may be sufficient in some cases.

We fully acknowledge the limitations of our small sample size. With only ten cases included, this study lacks sufficient statistical power to draw definitive conclusions regarding complication rates or treatment efficacy. As such, we present our findings as preliminary and observational, emphasizing the need for larger, multicenter prospective studies to validate our treatment strategy.

CONCLUSIONS

Double SAC with NASs may represent a technically feasible and safe option for managing ruptured BBAs in selected cases. However, due to the limited sample size and the lack of direct hemodynamic validation, our results should be interpreted as preliminary. Further studies with larger cohorts and comparative analyses, including hemodynamic modeling, are necessary to establish the role of this approach relative to FD therapy.

NOTES

ACKNOWLEDGEMENT

This work was supported by clinical research grant from Pusan National University Hospital in 2025.

Disclosures

The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper.

Fig. 1.

Patient No. 6. Serial angiographic images demonstrating the entire procedure of double stent-assisted coiling using NASs. (A) Initial right internal carotid artery angiography demonstrates a small, hemispherical bulge arising from the anterior wall of the right internal carotid artery (arrow), consistent with a blood blister-like aneurysm. (B) After aneurysm selection with a microcatheter and partial deployment of the first coil, the first NAS is partially deployed to begin covering the aneurysm neck. The coil delivery catheter, not jailed to the vessel wall, remains freely navigable within the aneurysm sac, allowing precise control of coil positioning. Black arrows indicate the distal markers of the first NAS, and the white arrow indicates the distal marker of the stent delivery microcatheter. (C) The first NAS is then fully deployed to fully bridge the aneurysm neck, particularly in response to persistent coil herniation. The stent delivery microcatheter is re-advanced over the pre-positioned microwire to its original location for second stent delivery. Arrows indicate proximal and distal markers of the stent delivery microcatheter. (D) Additional coil packing is performed through the jailed microcatheter. A small portion of the coil herniates out of the sac (arrow), indicating the need for reinforcement. (E) A second NAS is deployed within the first stent in a telescoping manner to reinforce the construct. The herniated coil loop is successfully repositioned back into the aneurysm sac by gentle manipulation through the stent struts. (F) Coiling is continued using the jailed microcatheter until homogeneous and dense coil packing is achieved, confirming stability within the fragile sac. (G) Final postprocedural angiography confirms complete obliteration of the aneurysmal bulge and preservation of parent artery patency without stenosis or thrombus formation. NASs, Neuroform Atlas stents

Fig. 2.

Patient No. 9. (A) A 47-year-old woman presenting with a ruptured blood blister-like aneurysm located at the right carotid-ophthalmic segment of the internal carotid artery. (B) Unsubtracted angiographic image after treatment shows overlapping Neuroform Atlas stents deployed across the aneurysm neck with dense coil packing. (C) Immediate post-procedural angiography demonstrates a filling defect along the stent wall and non-visualization of the anterior cerebral artery, consistent with acute in-stent thrombosis. (D) Following intra-arterial administration of 1 mg of abciximab, a glycoprotein IIb/IIIa inhibitor, repeat angiography at 15 minutes shows complete resolution of thrombus with restored antegrade flow in all distal branches.

Fig. 3.

Patient No. 2. Long-term outcome following recurrence and retreatment of a BBA. (A) Initial angiography shows a ruptured BBA (arrow) arising from the supraclinoid segment of the right internal carotid artery. (B) Unsubtracted angiogram reveals double Neuroform Atlas stents deployed across the aneurysm neck with coil embolization. (C) Immediate post-treatment angiography confirms complete occlusion of the BBA with preserved parent vessel flow. (D) Follow-up imaging at 8 months reveals recurrence of the aneurysm with coil compression and displacement, indicating treatment failure. (E) Retreatment is performed using a 5.0×20-mm Pipeline Vantage flow diverter (arrows), deployed to span the entire previously stented segment and re-cover the aneurysm neck. (F) Six-month follow-up angiography after flow diverter placement demonstrates complete aneurysm occlusion and full patency of the internal carotid artery without evidence of stenosis or recurrence. BBA, blood blister-like aneurysm.

Table 1.

Baseline clinical and imaging characteristics of the patients

Patient No.	Age/Sex	Hunt and Hess grade	Modified Fisher scale	Aneurysm location	Aneurysm size (depth × neck, mm)	EVD	Time to treatment (days)
1	64/F	2	2	L ICA	2.2 × 1.9	No	1
2	42/M	3	4	L ICA	3.4 × 4.0	Yes	1
3	50/F	4	3	R ICA	1.6 × 2.5	No	1
4	34/F	2	1	L ICA	2.3 × 3.8	No	1
5	48/F	3	1	R ICA	1.7 × 3.3	No	1
6	41/M	4	3	R ICA	2.9 × 3.4	No	1
7	38/F	2	1	R ICA	1.6 × 3.5	No	2
8	34/F	2	3	L ICA	3.3 × 2.2	No	1
9	47/F	2	3	R ICA	3.2 × 4.2	No	1
10	56/F	2	3	R ICA	2.8 × 2.9	No	3

EVD, external ventricular drainage; ICA, internal carotid artery; L, left; R, right.

Table 2.

Summary of the endovascular treatments with clinical and angiographic outcomes

Patient No.	Treatment modality	Used stents (number of deployed stents)	Intraoperative complication	Initial Raymond grade	Periprocedural complication (days)	Retreatment (days)	mRS at discharge (days)	Latest follow-up angiography (months)	mRS at latest (months)
1	DSAC	NAS (2)	No	3	No	No	1 (15)	CR (24)	0 (90)
2	DSAC	NAS (2)	No	1	No	No	2 (46)	Regrowth (11)	0 (22)
3	DSAC	NAS (2)	IST	1	No	No	6 (15)	NA	NA
4	DSAC	NAS (2)	IST	3	No	No	1 (25)	CR (4)	0 (52)
5	DSAC	NAS (2)	No	1	TE (7)	No	2 (24)	CR (44)	1 (54)
6	DSAC	NAS (2)	No	2	No	No	5 (180)	NA	NA
7	DSAC	NAS (2)	No	3	Regrowth (7)	2 NASs (7)	1 (15)	CR (18)	0 (44)
8	DSAC	NAS (2)	IST	1	No	No	1 (13)	CR (12)	0 (24)
9	DSAC	NAS (2)	IST	1	No	No	1 (15)	CR (7)	0 (18)
10	DSAC	NAS (2)	No	1	No	No	1 (15)	CR (6)	0 (24)

CR, complete resolution; DSAC, double stent-assisted coiling; IST, in-stent thrombosis; mRS, modified Rankin Score; NA, not applicable; NAS, Neuroform Atlas stent; TE, thromboembolism

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