Endovascular Management of Partially Thrombosed Intracranial Aneurysms: Single Center Experience and Systematic Review of Literature

Introduction: Partially thrombosed intracranial aneurysms (PTIAs) are reported to have highly variable natural history and response to current treatments available. Endovascular treatment (EVT)is generally considered the first line in the treatment of PTIA. Various EVTs can be used, ranging from deconstructive strategies like parent vessel occlusion to reconstructive strategies like stent-assisted coiling and flow diversion. There is a lack of clarity as to which is the ideal endovascular modality in the treatment of PTIAs.

Methods: This is a single institute retrospective review of all intracranial aneurysms treated from January 1, 2018 to February 28, 2023. 433 patients underwent EVT of their intracranial aneurysms. 18 of these patients had a PTIA. Additionally, a systematic review of the literature was conducted adhering to the PRISMA guidelines. A search on three databases was performed (MedLine via Pubmed, Scopus, and Embase). Search terms “[(endovascular treatment OR coiling embolization OR flow diverter OR WEB embolization) AND (partially thrombosed intracranial aneurysms)]”. The reference list of selected articles was reviewed with a selection of patients with PTIAs treated with endovascular therapy.

Results: Eleven studies in addition to present series resulted in a pool of 233 patients with PTIA treated endovascularly. Mass effect was the most common symptom leading to diagnosis (n = 104). Coil embolization was the most frequent treatment in 48.9% of patients (n = 114), followed by flow diversion (FD) in 27% (n = 63). Parent vessel occlusion (PVO) was used in 19.7% (n=46) while Woven-Endo-bridge device (WEB) in 4.2% (n=10). Occlusion rate was 78.3% for FD, 62.3% for coil embolization, 30% for WEB and 100% for PVO. Retreatment was required in 50% of the coiled patients, 15% of patients further treated with FD, 90% of patients treated with WEB , and 3% with PVO.

Conclusion : This retrospective study and systematic review demonstrate that deconstructive treatment had more successful results, however, they can only be applied to selected patients. Among the reconstructive techniques, FD showed the highest occlusion rates, whereas WEB devices showed the lowest occlusion rates.