Endovascular treatment of «mirror» aneurysms of the middle cerebral artery
Authors: Shchehlov D.V. , Hnelytsia O.P. , Svyrydiuk O.Je. , Gudym M.S. , Vyval M.B. , Mamonova M.YU. 
Published: May 2023

Objective ‒ to analyze the results of endovascular treatment of the «mirror» MCA aneurysms.Materials and methods. A retrospective analysis of the 172 patients with multiple cerebral aneurysms, who were treated between the period from April 2016 to February 2022 at Scientific and Practical Center of Endovascular Neuroradiology of the National Academy of Medical Sciences of Ukraine was conducted. «Mirror» MCA aneurysms were found in 20 (11.6 %) patients. Twenty patients had 54 aneurysms (8 patients had 12 aneurysms except MCA and 2 patients had 2 MCA aneurysms at one side). In one patient, a combination of «mirror» aneurysms of MCA and internal carotid artery was found. The group included 8 (40 %) men and 12 (60 %) women. The average age of the patients was (47.11 ± 11.73) years; range 23‒64 years. 8 (40 %) patients had subarachnoid hemorrhage due to MCA aneurysm rupture, in another 3 (15 %) patients another aneurysm was the cause of rupture, and 9 (45 %) of patients underwent surgery for unruptured aneurysms. The choice of treatment strategy and its staging, peri-procedural (bleeding, migration of coils, thrombus formation) and postoperative complications and the result of the treatment at the time of discharge and 3–6 months after the final treatment were analyzed. Qualitative assessment of aneurysm occlusion was performed intraoperatively and during follow-up angiographic examinations according to the modified Raymond‒Roy scale.Results. Of all 54 aneurysms in 20 patients, 49 aneurysms (40 MCA aneurysms and 9 aneurysms in other localization) were excluded endovascularly, 1 MCA aneurysm was clipped, and 4 aneurysms due to their small size were left for observation with regular follow-up examinations due to the low risk of rupture. Bilateral one-session endovascular occlusion of the «mirror» MCA aneurysms was performed in 11 patients, and staged procedure was performed in 9. Among 40 surgically treated «mirror» MCA aneurysms, 24 (60 %) were excluded with only coiling, 7 (17.5 %) with stent assistance coiling, 7 (17.5 %) with balloon assistance coiling, 1 aneurysm (2.5 %) was treated with parent artery occlusion, and 1 aneurysm (2.5 %) was clipped. Intraoperative complications occurred in 2 patients. One patient had an intraoperative rupture of an ICA aneurysm combined with «mirror» MCA aneurysms, which could not be stopped and ICA sacrifice was performed. In another, the coils migrated into the artery. In the first patient, the course of the disease was complicated with brain infarction in the left ICA region. Another patient was prescribed antiplatelet therapy in postoperative period, which was uneventful. Follow-up angiography studies were available in 16 patients. At the follow-up examination, significant recanalization of one of the MCA aneurysm was detected in two patients, who were successfully occluded during the second procedure without negative clinical outcome. In 15 patients at the control examination, the evaluation of the result according to the mRS was 1 – 2 points, and in 1 patient ‒ 3 points.Conclusions. Our series demonstrates that the outcomes of endovascular treatment of the «mirror» MCA aneurysms have comparable risks of periprocedural and post-procedural complications, with the general population of patients with both ruptured and unruptured MCA aneurysms. Best treatment strategy must be individualized with careful planning, considering which aneurysm should be excluded first, the possible sequence of treatment, depending on the clinical presentation, type of intervention, age, patient preference and available options. It is also necessary to assess the traumatic nature of treatment methods. In our opinion, endovascular interventions have obvious advantages over bilateral craniotomies or extended combined unilateral approaches, which in turn has the potential to improve the results of treatment, both in the short and long term, and to reduce its duration and cost.