Endovascular treatment of brain aneurysms under conscious sedation: a systematic review of procedural feasibility and safety

Over the last decades, minimally invasive techniques have revolutionized the endovascular treatment (EVT) of brain aneurysms. In parallel, the development of conscious sedation (CS), a potentially less harmful anesthetic protocol than general anesthesia (GA), has led to the course optimization of surgeries, patient outcomes, and healthcare costs. Nevertheless, the feasibility and safety of EVT of brain aneurysms under CS have yet to be assessed thoroughly. Herein, we systematically reviewed the medical literature about this procedure. In accordance with the PRISMA guidelines, four databases (PubMed, EMBASE, SCOPUS, and Cochrane Library) were queried to identify articles describing the EVT of brain aneurysms under CS. Successful procedural completion, complete aneurysm occlusion outcomes, intraoperative complications, clinical outcomes, and mortality rates assessed the feasibility and safety. Our search strategy yielded 567 records, of which 11 articles were included in the qualitative synthesis. These studies entailed a total of 1142 patients (40.7% females), 1183 intracranial aneurysms (78.4% in the anterior circulation and 60.9% unruptured at presentation), and 1391 endovascular procedures (91.9% performed under CS). EVT modalities under CS included coiling alone (63.2%), flow diversion (17.7%), stent-assisted coiling (10.6%), stenting alone (6.5%), onyx embolization alone (1.7%), onyx + stenting (0.2%), and onyx + coiling (0.2%). CS was achieved by combining two or more anesthetics, such as midazolam, fentanyl, and remifentanil. Selection criteria for CS were heterogenous and included patients’ history of pulmonary and cardiovascular diseases, outweighing the benefits of CS versus GA, a Hunt and Hess score of I–II, a median score of 3 in the American Society of Anesthesiology scale, and patient’s compliance with elective CS. Procedures were deemed successful or achieving complete aneurysm occlusion in 88.1% and 9.4% of reported cases, respectively. Good clinical outcomes were described in 90.4% of patients with available data at follow-up (mean time: 10.7 months). The procedural complication rate was 16%, and the mortality rate was 2.8%. No complications or mortality were explicitly attributed to CS. On the other hand, procedure abortion and conversion from CS to GA were deemed necessary in 5% and 1% of cases, respectively. The present study highlights the feasibility of performing EVT of brain aneurysms under CS as an alternative anesthetic protocol to GA. However, the limited nature of observational studies, methodological quality, the predominant absence of a comparative GA group, and clinical data during follow-up restrict a conclusive statement about the safety of EVT under CS. Accordingly, further research endeavors are warranted toward a higher level of evidence that can be translated into surgical practice.