Flow Diversion Versus Coiling in Small and Medium-sized Unruptured Aneurysms of Proximal Anterior Circulation with Complex Anatomy: a Matched-pairs Study.

BACKGROUND

The benefits of flow diversion (FD) versus endosaccular coiling (EC) in small and medium-sized proximal saccular aneurysms of anterior circulation, amenable to both methods, remain not well-established. This study aimed to compare the efficacy and safety of FD vs EC and evaluate the triggers of treatment modality choice in the aforementioned setting.

METHODS

The study had a retrospective design. Raw sample included 154 FD and 190 EC consecutively enrolled cases. All aneurysms were saccular, sized 4-14 mm, located at intradural ICA or A1/M1, not acutely ruptured and previously untreated. Median lesion size was 6.6 mm (90% < 10 mm), median neck diameter‑3.7 mm. Matched cohorts were 67 cases each, PS difference < 0.1 probit SD, all covariates: size, neck, location, shape, angle, multiplicity, rupture history, age, and incorporated arterial branch. Follow-up DSA available for 94.2% of raw sample at median 9 months.

RESULTS

In both raw and matched samples respectively, FD versus EC demonstrated higher rates of target aneurysm total occlusion (76.4% vs 53.2%, p < 0.001 and 80.3% vs 49.2%, p < 0.001), lower of rates of intraoperative technical adverse events (7.3% vs 21.4%, p < 0.001 and 9% vs 22.4%, p = 0.032) and retreatment (raw‑2.6% vs 15.4%, p < 0.001, matched‑1.5% equal). Rates of neurological morbidity and death were similar. The choice of FD was triggered by neck size and ratio, paraophthalmic location (OR = 2.57), multiplicity (OR = 4.1) and incorporated arterial branch (OR = 4.82), p < 0.001. Incorporated branch was associated with incomplete occlusion in both treatment modalities (p < 0.01).

CONCLUSION

In this study FD demonstrated higher rates of target aneurysm total occlusion, lower rates of intraoperative technical adverse events and similar rates of neurological morbidity and death, compared to EC.