Abstract
Introduction and importance
A1 dissection of the anterior cerebral artery (ACA) is difficult to treat with endovascular treatment (EVT). There are many EVT options for treating A1 aneurysms. However, the use of a flow diverter (FD) to cover the origin of the ACA is uncommon. We such a case.
Case presentations
A 51-year-old male experienced subarachnoid hemorrhage. The patient's Hunt–Hess scale score was Grade II. Angiography revealed a ruptured A1 dissecting aneurysm. Under general anesthesia, FD was used to cover the origin of the ACA. Postoperatively, the patient had no new neurological deficits. During the one-year follow-up, the patient recovered well and returned to normal life. Angiography revealed that the A1 dissecting aneurysm regressed, and the right ACA was patent and thinner than before. Follow-up magnetic resonance imaging did not reveal a brain infarction.
Clinical discussion
FD can be used to cover the origin of the ACA to remodeled the proximal ACA and A1 aneurysm by flow diverting effect. During follow-up, the ruptured A1 dissection can be remodeled and regressed.
Conclusion
Therefore, for ruptured A1 dissection, a FD to cover the origin of the ACA may be a feasible therapeutic option. After this, A1 dissecting aneurysms can regress due to reduced blood flow.
Keywords: Anterior cerebral artery, A1 segment, Dissection, Flow diverter, Case report
Highlights
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A1 dissection presents management challenges.
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FD coverage of ACA origin proves effective.
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A1 dissection may regress with flow reduction.
1. Introduction
Aneurysms of the A1 segment of the anterior cerebral artery (ACA) are rare, accounting for 1 % of all intracranial aneurysms [1]. Currently, endovascular treatment (EVT) is regarded as a reasonable treatment alternative. EVT is challenging because of the intricate positioning and stabilization of the microcatheter, as well as the risk of rupture from aneurysmal fragility. Traditional EVT includes coiling assisted by stenting. Occasionally, A1 aneurysms can be treated with a flow diverter (FD) covering the aneurysm neck. However, it is often difficult to use a FD to cover A1 aneurysms. When the FD covers the origin of the parent artery of the aneurysm, it can decrease the blood flow into the aneurysmal parent artery, gradually promoting aneurysm sac thrombosis; thus, deployment of the FD from the trunk of the middle cerebral artery (MCA) to the internal carotid artery and leaving the A1 aneurysm neck uncovered may be useful for treating A1 aneurysms. This technique has rarely been reported [2].
In this case report, a ruptured dissection of the A1 segment was successfully treated by an FD used to cover the origin of the A1 segment, and similar cases have never been reported. This case report has been reported in line with the 2025 SCARE checklist [3]. No any artificial intelligence was used in the manuscript development.
2. Case presentation
A 51-year-old male experienced severe headache for 8 h. He was previously healthy and had no history of stroke, systemic hypertension or diabetes mellitus. During a physical examination, the patient could obey the orders and had a stiff neck. His upper and lower limbs had grade V muscle strength. The patient's Hunt–Hess scale score was Grade II. Computed tomography (CT) revealed a subarachnoid hemorrhage (SAH) primarily on the right side (Fig. 1A). CT angiography (CTA) revealed a right ruptured A1 dissecting aneurysm; the aneurysm was located inside the SAH (Fig. 1B-D). EVT was performed.
Fig. 1.
Diagnostic images. A: CT image showing a subarachnoid hemorrhage (asterisk) focusing on the right suprasellar cistern. B: CT angiography image showing right A1 dissection (arrowhead); C: Maximum-intensity projection image showing the location of A1 dissection (arrowhead); D: CT image showing A1 dissection inside the hemorrhage. In panels B-D, long arrows indicate the location of A1 dissection, and rupture was confirmed. E: Upper panel: DSA of the right carotid artery showing A1 dissection (arrow) and a thin ACA; Lower panel: DSA of the left carotid artery showing the left thin ACA. F: Three-dimensional reconstructive DSA images showing A1 dissection (arrow with ACA) and a PcomA aneurysm (arrow with PcomA). Abbreviations: ACA: anterior cerebral artery; A1: first segment of the ACA; CT: computed tomography; DSA: digital subtraction angiography; L: left; PcomA: posterior communicating artery; R: right.
Digital subtraction angiography (DSA) performed under general anesthesia confirmed a right ruptured A1 dissecting aneurysm and an unruptured aneurysm of the posterior communicating artery (PcomA) (Figs. 1E-F). Then, it was determined that the PcomA aneurysm would be coiled with FD assistance, and the ACA origin would be covered by the FD to reduce blood flow to prevent rebleeding of the A1 aneurysm.
After the Excelsior XT-27 microcatheter (Stryker Neurovascular, Fremont, California, USA) was positioned in the MCA under the guidance of a Synchro-14 guidewire (Stryker Neurovascular, Fremont, California, USA), the PcomA aneurysm was catheterized with an Echelon-10 microcatheter (Medtronic, Irvine, CA, USA). A lattice FD (AccuMedical, Beijing, China) (4.1–20 mm) was then semi-deployed to cover the origin of the ACA and the PcomA aneurysm neck. Prism coils 3–6 cm and 2–4 cm in size were used to pack the aneurysm. The lattice FD was then completely released (Fig. 2A).
Fig. 2.
Treatment and follow-up images. A: Left panel: Unsubtracted DSA image showing that the FD covered the A1 origin. Middle panel: Unsubtracted DSA image showing that the PcomA aneurysm (arrow) was coiled. Right panel: X-ray image showing the FD and coils. B: Postoperative one-week CT angiography image showing that the FD covered the A1 origin. C: Panels 1–2: One-year follow-up DSA and three-dimensional reconstructed images showing that the right A1 segment became thinner after one year, and the dissection appeared to have regressed slightly. Panel 3: DSA image showing that the left ACA was thin. Panel 4: Three-dimensional reconstructive DSA image showing complete occlusion of the PcomA aneurysm. D: Magnetic resonance T1-weighted (upper panel) and T2-weighted (lower panel) images showing no abnormalities. Abbreviations: ACA: anterior cerebral artery; A1: first segment of the ACA; CT: computed tomography; DSA: digital subtraction angiography; FD: flow diverter; L: left; PcomA: posterior communicating artery; R: right.
Postoperatively, the patient had no new neurological deficits. CTA performed one week postoperatively revealed patency of the supraclinoid internal carotid artery and ACA (Fig. 2B). At the one-year follow-up, the patient recovered well and returned to normal life. DSA revealed that the A1 dissecting aneurysm had regressed, the right ACA was patent and thinner than before, and the PcomA aneurysm was completely occluded (Figs. 2C and 3). Magnetic resonance imaging revealed no infarction.
Fig. 3.
Comparison of A1 dissection pre- and post-EVT. Three-dimensional reconstructed DSA images showing that A1 dissection regressed one year after EVT. The frames and long arrows indicate the region with A1 dissection. Abbreviations: ACA: anterior cerebral artery; A1: first segment of the ACA; DSA: digital subtraction angiography; EVT: endovascular treatment.
3. Discussion
EVT is a useful option for treating A1 aneurysms. Many EVT methods can be used to treat saccular A1 aneurysms (Fig. 4). However, owing to the anatomical site of the aneurysm, coiling is considered technically unfavorable. In recent years, FDs have become a popular option for treating intracranial aneurysms. FDs work by reconstructing the parent artery, redirecting blood flow, and occluding the aneurysm. The FD structure is subsequently endothelialized, forming a permanent biological seal together with the parent artery. FDs can cure A1 aneurysms by covering the aneurysm neck (Fig. 5).
Fig. 4.
EVT for A1 aneurysms by coiling or FD coverage. A: Single coiling: Upper panel: DSA image showing an A1 aneurysm (arrow). Middle panel: Unsubtracted DSA image showing the coil in the aneurysm (arrow). Lower panel: DSA image showing that the aneurysm was embolized. B: Coiling with the assistance of stenting: Upper panel: Roadmap showing that the A1 aneurysm was catheterized (arrow). Middle panel: Unsubtracted DSA image showing the coil in the aneurysm (arrow) and the baby Leo stent covering the aneurysm. Lower panel: DSA image showing that the aneurysm was embolized. C: FD coverage: Upper panel: DSA image showing an A1 aneurysm (arrow) and an anterior communicating aneurysm. Middle panel: Vascular reconstructive DSA image showing that the A1 aneurysm was covered by the FD. Lower panel: Six-month follow-up DSA image showing that the aneurysm was cured. D: Coiling via the contralateral approach: Upper panel: DSA image showing that the A1 aneurysm (arrow) was catheterized via the contralateral ACA. Middle and lower panels: Unsubtracted DSA images showing that the aneurysm was coiled (arrows) and that A1 was occluded (arrowheads). E: Coiling by the waffle-cone technique: Upper panel: DSA image showing multiple aneurysms, including an A1 aneurysm (arrow). Middle panel: X-ray image showing that the A1 aneurysm was coiled with the assistance of a Solitaire stent using the waffle-cone technique. Lower panel: DSA image showing that all the aneurysms were embolized. Abbreviations: ACA: anterior cerebral artery; A1: first segment of the ACA; DSA: digital subtraction angiography; EVT: endovascular treatment; FD: flow diverter.
Fig. 5.
EVT for A1 aneurysms by using an FD to cover the origin of the ACA. A-B: Progressive ACA atrophy after FD coverage: A: Left panel: DSA image showing a supraclinoid ICA aneurysm (arrow) and a normal-sized ACA. Right panel: After the ACA was covered by the FD, the six-month follow-up DSA image showing the stenotic and thin ACA (arrow). B: Left panel: Unsubtracted DSA image showing coiling for the PcomA aneurysm and the deployed FD. Right panel: DSA image showing the intima lining of the origins of the ACA and PcomA (arrows), indicating the forthcoming occlusions of the ACA and PcomA. C: Panel 1: Computed tomography angiography image showing an aneurysm (arrow) at the internal carotid artery bifurcation. Panel 2: DSA image showing contrast agent retention in the aneurysm after the origin of the ACA was covered by the FD. Panel 3: X-ray image showing the FD. Panel 4: Six-month follow-up DSA image showing the intimal line across the origin of the ACA. D: Left panel: DSA image showing a supraclinoid ICA aneurysm and an A1 aneurysm (arrow). Middle panel: Unsubtracted DSA image showing that the supraclinoid ICA aneurysm was coiled and that the A1 aneurysm was covered by the FD. Right panel: DSA image showing contrast retention in the A1 aneurysm (arrow). E: Upper panel: DSA image showing that the A1 aneurysm was coiled and that the origin of the ACA was covered by the FD. Lower panel: X-ray image showing the coil and FD. F: Left panel: Unsubtracted DSA image showing that the FD covered the supraclinoid ICA dissection; the arrow indicates the A1 dissecting aneurysm. Middle panel: Roadmap image showing that the A1 aneurysm was catheterized (arrow) via the contralateral approach. Right panel: Unsubtracted DSA image showing that the A1 dissection was coiled loosely (arrow). Abbreviations: ACA: anterior cerebral artery; A1: first segment of the ACA; DSA: digital subtraction angiography; EVT: endovascular treatment; FD: flow diverter; ICA: internal carotid artery.
A new EVT choice for the treatment of A1 aneurysms is to use an FD to cover the origin of the ACA. After the origin of the ACA is covered by the FD, the blood flow can be diverted into the MCA to reduce the hemodynamic stress in the diseased aneurysmal ACA to promote A1 aneurysm thrombosis. In 2022, Giorgianni et al. reported the case of a 60-year-old woman with an unruptured A1 aneurysm. An FD was placed from the trunk of the MCA to the internal carotid artery without directly covering the A1 aneurysm neck. Angiography at the 24-month follow-up confirmed the resolution of the aneurysm [2]. Mahmoud et al. explained the A1 aneurysm healing process through two mechanisms: 1) proximal ACA occlusion and reperfusion by the anterior communicating artery (AcomA) and 2) hemodynamic modification, in which slowing of the flow across the ACA may alter the intra-aneurysmal environment and progress to aneurysm thrombosis [4]. However, although it is effective, when this approach is used to treat A1 aneurysms, healing may take a long time (Fig. 6).
Fig. 6.
Short-term outcomes of an A1 aneurysm treated by an FD covering the origin of the ACA. Panel 1: Three-dimensional reconstructive DSA image showing an A1-origin aneurysm and a PcomA aneurysm. Panel 2: Ten-month follow-up DSA image showing the regressed PcomA aneurysm (long arrow from Panel 1), the occluded distal ACA (long arrow from Panel 1), and the intimal line of the ACA origin (long arrow from Panel 1). Panel 3: Three-dimensional reconstructive DSA showing that the A1 aneurysm did not regress (long arrow from Panel 1); a longer follow-up time may be needed. Panel 4: X-ray image showing the FD. Abbreviations: ACA: anterior cerebral artery; A1: first segment of the ACA; AN: aneurysm; DSA: digital subtraction angiography; FD: flow diverter; PcomA: posterior communicating artery.
The A1 aneurysm in our case was different from that reported by Giorgianni et al.; it was a ruptured and dissecting aneurysm with severe stenosis of the parent artery. The patient's treatment was challenging. Among the types of EVT that can be chosen in our case, coiling was impossible due to the thin ACA. Owing to the isolated ACA without a competent AcomA, it was unacceptable to occlude the ACA. It was also impossible to deploy the FD to reconstruct the ACA due to severe stenosis of the proximal ACA. Therefore, an FD can be considered to cover the origin of the ACA, by which remodeling of the proximal ACA and A1 aneurysm can be expected. In our patient, after one year of follow-up, the ruptured A1 dissection had remodeled and regressed, and the ACA was patent (Fig. 3). The healing of the aneurysm in our case can be explained by the second mechanism (hemodynamic modification) that was proposed by Mahmoud et al. because the ACA was not occluded.
Certainly, for our patient, after the FD covered the origin of the ACA, during the follow-up, the occlusion of both the ACA and A1 dissection was the best expected outcome. However, FDs have varying effects on the covered branches. The collateral circulation determines the fate of covered branches [5]. For branches without sufficient collateral flow, the occlusion rate is low due to the high-pressure gradient. However, for branches with sufficient collateral flow, the occlusion rate is high [6].
Hemodynamic and anatomic plasticity and reorganization of the ACA can occur when an FD covers the ACA. If the AcomA is competent, the ACA covered by the FD can progress to progressive stenosis or even occlusion, the contralateral ACA can take over the ACA covered by the FD, and the contralateral ACA diameter can even increase [[7], [8], [9]]. In our case, not only was there no competent AcomA, but the contralateral ACA was also hypoplastic. Therefore, the ACA with A1 dissection was not occluded. However, ACA remodeling occurred, and the ruptured dissection regressed due to the reduced blood flow.
4. Conclusion
For ruptured A1 dissection, when treatment is difficult with other EVT options, An FD may be a feasible therapeutic option to cover the origin of the ACA. After an FD covers the ACA, A1 dissection can regress due to reduced blood flow.
Author contribution
Jinlu Yu contributed to data collection, writing-original draft, the manuscript review and revision.
Consent for publication
Written informed consents were obtained from the patients for publication in this case report and any accompanying images. Written consents are available for review by the Editor-in-Chief of this journal.
Ethical approval
Ethical approval is not needed for case reports in our institution (The First Hospital of Jilin University).
Guarantor
Jinlu Yu.
Research registration number
Not applicable. This is a case report not a research study.
Funding
No funding.
Conflict of interest statement
The authors declare that they have no competing interests.
Acknowledgements
None.
Data availability
Data will be made available on request.
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
Data will be made available on request.