Treatment of unruptured distal anterior circulation aneurysms with flow diverter stents: A meta-analysis

Background The safety and efficacy of FD among distal AC aneurysms must be proved. Purpose To analyze the outcomes after FD among MCA, AcomA, and DACA aneurysms. Data sources A systematic search of three databases was performed for studies published from 2005 to 2018. Study selection According to PRISMA guidelines, we included studies reporting FD of distal AC aneurysms. Data analysis Random-effects meta-analysis was used to pool aneurysm occlusion and complication rates. From the individual patient data, univariate and multivariate analysis were used to test predictors of occlusion and complications. Data synthesis We included 27 studies (484 aneurysms). Long-term adequate occlusion rate (OKM C-D) was 82.7 % (295/364, 95 % CI = 77.4 %–87.9 %, I2 = 52 %). Treatment-related complications were 12.5 % (63/410, 95 % CI = 9 %–16 %%, I2 = 18.8 %), with 5.4 % (29/418, 95 % CI = 3.2–7.5 %, I2 = 0 %) of morbidity. MCA location was an independent factor associated with lower occlusion (OR = 0.5, P = 0.03) and higher complication rates (OR = 1.8, P = 0.02), compared to AcomA and DACA aneurysms. PED (vs other stents) gave better occlusion rates (OR = 2.6, P = 0.002), whereas large/giant aneurysms were associated with higher odds of complications (OR = 2.2, P = 0.03). The rates of occlusion and narrowing of arteries covered by flow-diverter stents were 6.3 % (29/283, 95 % CI = 3.5 %–9.1 %, I2 = 4.2 %) and 23.8 % (69/283, 95 % CI = 15.7 %–32 %, I2 = 80 %), respectively. Symptoms related to occlusion and narrowing of the jailed arteries were 3.5 % (6/269, 95 % CI = 1.1 %–5 %, I2 = 0 %) and 3 % (6/245, 95 % CI = 1 %–4 %, I2 = 0 %), respectively. Limitations Small and retrospective series. Conclusions FD among distal AC aneurysms is effective, leading to adequate aneurysm occlusion in 83 % of cases. However, this strategy presents some limitations among MCA, and for larger lesions especially related to the higher rate of complications. Compared to the other devices, PED seems to be associated with a higher occlusion rate.