O-020 Comparative analysis of clinical outcomes after treatment of complex intracranial aneurysms of anterior circulation with flow diverters and PAO with bypass: prospective trial

Abstract

Background Complex intracranial aneurysms included giant aneurysms (maximum dome size exceeds 25 mm), fusiform or blister aneurysms, saccular aneurysms with wide neck (dome/neck ratio more than 1.5:1), aneurysms with major artery originating from the neck or sac, those with a significant thrombus in the lumen and considerable atherosclerotic changes in the neck. Despite the presence of an extensive data about microsurgical and endovascular techniques for treatment of complex intracranial aneurysms, there are still questions about feasibility and safety of parent vessel occlusion (PVO) with bypass and flow-diversion. Here we presented a result of trial, comparing clinical and surgical outcomes of patients with complex intracranial aneurysms, who underwent bypass or flow-diversion procedures. Methods Study of complex intracranial aneurysms treatment (SCAT) is open, prospective, parallel group, 1:1 trial with superiority design, conducted in 2 neurosurgical centers in Novosibirsk (Russia). The protocol of study was approved by Local Institutional Review Board and published on clinicaltrials.gov. (Identifier NCT03269942). Patients with complex intracranial aneurysms of anterior circulation with neck is more than 4 mm wide, dome/neck ratio is equal or less than 2:1, which is suitable for flow diversion and occlusion with bypass was included in the study. After enrollment of 111 patient the propensity score with 1-to-1 nearest neighbor caliper matching without replacement was used to minimize bias for all major clinical and angiographic characteristics. The number of patients accounted 40 in each group after PSM. Neurological deterioration was sought when increasing on more than 1 mRS grade had been achieved or worsening more or equal to mRS 3 had been occurred. Results The mean age of patients was 53.5 (95% CI, 47.5–59.25) in bypass group and 54.5 (95% CI, 47–58). The distribution of aneurysms by segments were as follows: A2 segment of ACA (1 patient), AcomA (3 patients), cavernous carotid (29 patients), ophthalmic segment of ICA (9 patients) communicating segment of ICA (11 patients), M1 segment (20 patients) and M2 segment of MCA (7 patients). The mean size of aneurysms by MRI was 12 (95% CI, 9–16.75) in bypass group and 15 (95% CI, 9–20.5) in group of flow diversion. After comparison of groups by χ2 test the difference on the basis of clinical outcomes was found to be statistically significant (p=0.014). The complete occlusion of aneurysms in 12 months occurred in 38 patients after PAO with bypass (95%) and in 26 patients after flow diversion procedure (65%). The statistical significance was found between groups in terms of angiographic outcomes (p=0.001). The rate of morbidity and mortality in groups was respectively: 5% and 0% in flow diversion group and 22.5% and 5% in group of PAO with bypass. Conclusion Despite the lower complete occlusion rate in comparison with PAO with bypass, an implantation of flow-diverting device is providing significantly better clinical outcome in 12 months in treatment of complex intracranial aneurysms. Disclosures R. Kiselev: None. A. Dubovoy: None. D. Kislitsin: None. A. Gorbatykh: None. A. Moskalev: None. K. Orlov: None.