INTRODUCTION
Recurrent posterior communicating artery (PCOM) aneurysms following initial endovascular treatment pose a therapeutic challenge, particularly when prior flow diverter (FD) placement fails to achieve complete occlusion [1,2]. Antegrade access through the internal carotid artery (ICA) may be technically precluded when the aneurysmal neck is covered by a previously deployed FD, preventing further catheterization into the aneurysm [3]. We report a case in which a recurrent PCOM aneurysm was successfully treated via retrograde access through the posterior circulation, allowing for a Woven EndoBridge (WEB; Terumo Neuro) deployment. This approach resulted in early complete obliteration without complications. To the best of our knowledge, this is the first report of retrograde WEB deployment for a recurrent PCOM aneurysm following FD treatment.
CASE REPORT
Patient Information
A patient in their 60s underwent simple coil embolization for a ruptured cerebral aneurysm at an outside hospital in October 2023. The aneurysm had been previously treated with surgical clipping approximately 10 years earlier. Residual filling was observed after the procedure. In May 2024, she was referred to our institution for further management. As the aneurysm, located at the right PCOM, was associated with a prominent PCOM and an intact ipsilateral P1 segment—features consistent with a dominant-type PCOM configuration—we elected to place a Pipeline Flex with Shield Technology (Medtronic). Follow-up digital subtraction angiography (DSA) performed 1 year later demonstrated coil compaction and aneurysm regrowth, and additional treatment was scheduled.
Treatment Planning and Anatomical Considerations
As the aneurysmal neck was covered by the previously deployed FD, antegrade access for additional intrasaccular treatment was deemed technically unfeasible. Moreover, additional FD deployment may not be effective and requires prolonged dual antiplatelet therapy (DAPT). However, the presence of a narrow but patent P1 segment allowed for consideration of a retrograde approach via the posterior circulation. Vertebral artery angiography confirmed sufficient collateral flow from the posterior circulation to the distal right posterior cerebral artery (PCA). Based on this anatomical configuration, we planned retreatment via a retrograde approach with the intention of occluding the aneurysm together with the origin of the PCOM.
Procedural Details
Following the regional standard regimen, DAPT with aspirin (100 mg/day) and prasugrel (3.75 mg/day) was initiated 2 weeks before the subsequent treatment. The overall procedural steps are illustrated in Fig. 1. Under general anesthesia, an 8-Fr long sheath was inserted into the right femoral artery, and a 6-Fr slender sheath was placed into the right distal radial artery. A 6-Fr 95-cm RIST catheter (Medtronic) was advanced into the right ICA, and a Scepter XC balloon catheter (4×11 mm; Terumo Neuro) was positioned at the petrous segment of the right ICA. From the femoral access, an 8-Fr Fubuki XF (ASAHI INTECC) was navigated into the left vertebral artery. During imaging, temporary balloon occlusion of the right ICA was performed using the Scepter XC to visualize the retrograde route from the P1 segment to the PCOM. After confirming the retrograde route, a Vecta 46 (Stryker) distal access catheter was advanced to the top of the basilar artery, through which a Headway 21 microcatheter (Terumo Neuro) was guided into the aneurysmal sac. A WEB SL device (6×3 mm; Terumo Neuro) was deployed within the aneurysm with the intentional goal of occluding the aneurysm together with the origin of the PCOM [4]. The device was shaped to conform to the aneurysmal cavity while ensuring stable positioning. Final angiography immediately after WEB deployment demonstrated stagnation of intra-aneurysmal flow and reduced filling of the PCOM, consistent with effective flow disruption, while distal PCA territory perfusion was sufficiently maintained via vertebral artery. No procedure-related complications, including perforator infarction of PCOM, were observed. The patient remained neurologically intact and discontinued DAPT 1 month after the procedure. Follow-up DSA performed 3 months later confirmed complete obliteration of the aneurysm and persistent occlusion of the PCOM. Based on these findings, single antiplatelet therapy was subsequently discontinued. The endovascular procedure for this case is presented in Supplementary Video 1.
DISCUSSION
Clinical Significance and Novelty of the Present Case
In this case, we successfully achieved early and complete obliteration of a previously treated cerebral aneurysm using retrograde deployment of a WEB device. The aneurysm had persisted despite prior treatment with a FD, and anatomical constraints made antegrade access unfeasible. By leveraging the presence of a patent P1 segment and acceptable flow from the posterior circulation, which indicated that PCOM occlusion would be tolerated [5], a retrograde approach enabled safe and effective intrasaccular treatment with a WEB device. While retrograde approaches have been reported [6,7], this case is unique in demonstrating retrograde deployment of a WEB device for a recurrent PCOM aneurysm after prior FD placement.
Comparison with Conventional Retreatments and Advantages of WEB
FD placement is generally considered effective for previously untreated PCOM aneurysms with a dominant configuration, defined as a PCOM diameter greater than that of the P1 segment [8]. In addition, stent-assisted coil embolization for this aneurysm subtype has shown suboptimal treatment outcomes and may involve technically complex procedures [1]. Therefore, we selected FD placement in the initial retreatment. However, when the aneurysm persists despite FD treatment, retreatment becomes challenging. Although adding a second FD or attempting retrograde coil embolization to achieve PCOM occlusion are possible options, the former does not necessarily guarantee effective occlusion, and the latter carries a risk of perforator infarction due to thrombus formation resulting from flow stagnation at the blind stump [5,9]. Moreover, coil embolization requires high packing density within the confined space of the aneurysm and the PCOM to achieve immediate occlusion of both structures, a process that often demands advanced technical skills. In contrast, the WEB device can achieve high metal density within a confined aneurysmal cavity with less operator dependency and may promote gradual thrombosis. This property may prevent thrombus formation at the blind stump resulting from abrupt PCOM occlusion and thereby reduce the risk of thromboembolic complications involving perforating branches such as the premamillary artery. In this context, retrograde WEB deployment may serve as a more controlled and effective alternative, particularly in anatomically suitable cases where PCOM occlusion is acceptable.
Technical Considerations for Retrograde WEB Deployment
In retrograde approach, it is crucial to confirm the curvature of the P1 segment of the PCA and the PCOM. Depending on the angle of the curvature, there is a risk of perforator avulsion injury due to stretching as the device passes through this segment. Three-dimensional DSA performed during temporary ICA balloon occlusion is effective for confirming the P1–PCOM junction and evaluating the feasibility of a retrograde approach. In this case, we selected a Headway 21 microcatheter over the VIA 21 (Terumo Neuro) for WEB delivery because of its narrower tip diameter and softer distal end compared to the dedicated VIA catheter for WEB [10]. These characteristics offer superior trackability and are better suited for navigating the often sharply angled P1–PCOM junction. In addition, to occlude both the aneurysm and the PCOM, the WEB was carefully deployed into the aneurysm so that its tail protruded into the proximal third of the PCOM, without extending beyond this segment, because excessive protrusion might risk compromising important perforators. Among these, the premamillary artery is the largest and most clinically significant, and its occlusion can lead to memory disturbance and hemiparesis due to infarction of the genu of the internal capsule [5,11]. This artery typically originates from the caudal portion of the PCOM, which is near the PCA, or between the caudal and middle third segments [5]. Therefore, in retrograde WEB deployment, slight protrusion into the proximal PCOM is essential, provided that appropriate positioning within the aneurysm is ensured to achieve early and safe aneurysm occlusion.
This strategy is technically demanding and requires favorable vascular anatomy, including a patent P1 segment and sufficient posterior circulation access. Furthermore, its applicability is limited to cases in which occlusion of the PCOM is clinically acceptable. Finally, no definitive conclusions can be drawn from a single case regarding the potential advantages of retrograde WEB deployment over conventional techniques such as retrograde coiling.
Clinical Implication
Retrograde WEB deployment may be a useful retreatment option for recurrent PCOM aneurysms after FD placement, particularly in cases where the antegrade approach is not suitable. In selected cases, WEB can achieve effective intrasaccular occlusion and facilitate intentional PCOM closure, even in anatomically constrained situations.
PDF Links
PubReader
ePub Link
XML Download
Full text via DOI
Full text via PMC
Download Citation
Supplement
Print
