Four flow diverter stents for the treatment of a giant unruptured vertebrobasilar dissecting aneurysm: A case report

Abstract

The use of four consecutive flow diverter stents to treat a giant unruptured fusiform vertebrobasilar dissecting aneurysm (VBDA) is extremely rare, and their safety and efficacy have not been fully established. This case report describes the case of a middle-aged Chinese male patient who underwent endovascular treatment for a giant unruptured fusiform VBDA using four flow diverter stents deployed in a bridging sequence. Digital subtraction angiography revealed a fusiform aneurysm extending from the V4 segment of the left vertebral artery to the mid-basilar artery, measuring approximately 7.90 mm × 64.5 mm. The procedure achieved complete aneurysm occlusion and satisfactory arterial remodeling without significant thrombosis. The patient successfully underwent endovascular treatment with four flow diverter stents, resulting in stable flow in the reconstructed parent artery. At 12-month follow-up, no new neurological deficits were observed. This case provides valuable insights into the management of giant unruptured posterior circulation fusiform aneurysms, particularly in patients with well-developed bilateral vertebral arteries and posterior inferior cerebellar arteries.

Background

Vertebrobasilar dissecting aneurysms (VBDAs) are rare, with an estimated incidence of 0.0001%–0.00015%. ¹ Clinical manifestations include ischemic stroke, cranial nerve or brainstem compression, intracranial hemorrhage, and hydrocephalus. ² Despite their low prevalence, VBDAs are associated with high mortality, morbidity, and recurrence rates, ³ emphasizing the need for prompt therapeutic intervention. ⁴ This report describes a rare case of a giant unruptured fusiform VBDA treated with four sequential flow diverter stents (FDS), providing insights into its clinical management.

Case presentation

Clinical presentation

A Chinese male patient, aged approximately 50 years, presented with dizziness persisting for over 2 months. In mid-2023, he received treatment at the Affiliated Hospital of Guizhou Medical University (28 Guiyi Road, Yunyan District, Guiyang City, Guizhou Province). Neurological examination revealed positive Babinski and Chaddock signs in the right lower limb. Cranial computed tomography (CT) and magnetic resonance imaging (MRI) demonstrated acute cerebral infarction in the right cerebellar hemisphere (Figure 1(a) to (c)). Preoperative digital subtraction angiography showed fusiform dilation of the V4 segment of the left vertebral artery (VA) and mid-to-lower basilar artery (BA), characterized by a dual-lumen sign and delayed filling of the contrast agent within a pseudocavity. These findings confirmed the diagnosis of VBDA with dimensions of approximately 7.90 mm × 64.5 mm (Figure 2(a)). The lesion was classified as a giant unruptured fusiform VBDA. The patient provided written informed consent, and the study was approved by the Ethics Committee of Guizhou Medical University (No.2024-266). The reporting of this study conforms to the Case Report (CARE) guidelines. ⁵

Figure 1.

Preoperative cranial imaging. (a) CT showing hypodense areas in the right cerebellar hemisphere (white arrow) and (b, c) MRI showing patchy abnormal signals in the right cerebellar hemisphere indicative of acute infarction (white arrows). CT: computed tomography; MRI: magnetic resonance imaging.

Figure 2.

Angiographic imaging during treatment. (a) DSA showing fusiform aneurysmal dilation involving the left VA V4 segment and mid-to-lower BA, with aneurysm dimensions of approximately 7.90 mm × 64.5 mm; proximal arterial diameter of 3.7 mm; and distal arterial diameter of 3.5 mm (white arrow) and (b, c) three-dimensional reconstruction showing stent deployment and aneurysm coverage (left black arrows and right white arrows). DSA: digital subtraction angiography; VA: vertebral artery; BA: basilar artery.

Treatment

After a 7-day antiplatelet regimen (0.1 g aspirin and 75 mg clopidogrel daily), the patient underwent endovascular treatment. Under ROADMAP guidance, a 6F guidewire was advanced over a loach guidewire to the V3 segment of the left VA. The PHENOM-27 stent guidewire was then deployed via an AVIGO microguidewire to the distal segment of the BA aneurysm, with microcatheter angiography confirming its placement within the true lumen. Angiography confirmed a fusiform aneurysm involving the left VA V4 segment and mid-to-lower BA. Four sequential FDS (NY42535, NY42530, NY42525, and NY4030; Nuanyang Medical Devices, Nantong, China) were deployed across the vertebrobasilar lesion. Post-deployment angiography confirmed complete coverage of the aneurysm, with satisfactory dilation and apposition of all stent segments. Intraoperatively, tirofiban was continuously infused to prevent intrastent thrombosis. Contrast agent retention was observed within the aneurysm cavity, while the distal left VA, BA, and bilateral posterior cerebral arteries remained patent. Final angiography revealed complete aneurysm occlusion with preserved distal arterial flow and no signs of thrombus formation or stent migration (Figure 2(b) and (c)). Postoperatively, the patient was administered dual antiplatelet therapy (0.1 g aspirin and 75 mg clopidogrel daily), which was adjusted after 21 days to clopidogrel (75 mg once daily) for ongoing antiplatelet management.

Postoperative course

The patient continued dual antiplatelet therapy with aspirin and clopidogrel. Follow-up imaging at 6, 10, and 12 months (Figure 3(a) to (c)) demonstrated patent stents, complete aneurysm occlusion, and satisfactory remodeling of the affected artery (Figure 4(a) to (c)). The patient reported no new neurological deficits throughout the follow-up period.

Figure 3.

Postoperative cranial imaging. (a–c) MRI and DWI showing no new infarctions or hemorrhages after treatment. MRI: magnetic resonance imaging; DWI: diffusion-weighted imaging.

Figure 4.

Follow-up angiographic imaging. (a) At 6 months, the stents were patent and the aneurysm was occluded (proximal arterial diameter of 3.4 mm, distal arterial diameter of 3.2 mm) and (b, c) at 10 and 12 months, no significant contrast agent was observed between the stent and vessel wall; the contrast agent in the BA remained visible. BA: basilar artery.

Discussion and conclusion

Discussion

Treatment options for giant posterior circulation fusiform aneurysms include conservative medical management, surgical bypass, and endovascular intervention. Conservative therapy may be suitable for asymptomatic patients; ⁶ however, the natural course of VBDA carries a high risk of rupture and poor prognosis. ⁷ Surgical approaches, including high-flow bypass and aneurysm clipping, are often limited by the deep anatomical location and proximity to critical neurovascular structures.^8–10

Endovascular therapy, such as coil embolization, stent-assisted coiling, and flow diverter (FD) placement, provides a minimally invasive alternative with fewer complications, favorable clinical outcomes, and low mortality and is increasingly preferred for VBDA.^11–14 FDS provide hemodynamic stabilization by redirecting blood flow, promoting aneurysm thrombosis, and facilitating arterial remodeling.^15–20

This case demonstrates the use of multiple sequential FDS to treat a giant unruptured fusiform VBDA. The extensive aneurysmal segment and unique anatomical considerations necessitated deployment of four overlapping FDS to ensure complete coverage. The procedure resulted in successful aneurysm occlusion, satisfactory vascular remodeling, and no adverse events during follow-up.

Challenges and future perspectives

This treatment approach presents technical challenges, including stent deployment accuracy, selection of overlapping stent segments, and the risk of thromboembolic complications. In this case, the dissection segment was extensive, and a single blood flow guide device with uniform vascular diameter could not adequately cover the lesion, necessitating connection of multiple devices. Additionally, involvement of the vertebrobasilar artery increases the risk of severe complications, such as stent detachment or occlusion of major perforating vessels and the BA. To reduce the risk of perforator-related complications, precise preoperative assessment of perforating arteries and collateral circulation is critical. Deployment of a stent slightly oversized relative to the parent artery is recommended to prevent excessive expansion, which can lead to increased metal coverage or malapposition, thereby elevating the risk of thrombus formation. Direct coverage of perforating arteries should be avoided whenever possible. Standardized antiplatelet therapy, administered both preoperatively and postoperatively, is essential, and intravenous tirofiban should be used intraoperatively to prevent acute thrombus formation. Strict blood pressure control is also necessary to prevent hypoperfusion. The favorable outcome in this case highlights the potential efficacy of FD therapy for complex VBDA; however, larger studies are required to validate its safety and generalizability.

Conclusion

The use of multiple sequential FDS for treating giant unruptured fusiform VBDA represents a rare but instructive approach. This case demonstrates the feasibility of endovascular tandem deployment of multiple FDS in a giant unruptured VBDA with well-developed bilateral VAs and posterior inferior cerebellar arteries. These findings provide clinical evidence supporting the management of giant unruptured posterior circulation aneurysms and inform future applications of flow diversion technology. Further studies are warranted to optimize stent deployment strategies and antiplatelet regimens to improve clinical outcomes.