Treatment of Unruptured Distal Anterior Circulation Aneurysms with Flow-Diverter Stents: A Meta-Analysis

Abstract

BACKGROUND: The safety and efficacy of flow diversion among distal anterior circulation aneurysms must be proved. PURPOSE: Our aim was to analyze the outcomes after flow diversion among MCA, anterior communicating artery, and distal anterior cerebral artery aneurysms. DATA SOURCES: A systematic search of 3 databases was performed for studies published from 2005 to 2018. STUDY SELECTION: According to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we included studies reporting flow diversion of distal anterior circulation aneurysms. DATA ANALYSIS: Random-effects meta-analysis was used to pool aneurysm occlusion and complication rates. From the individual patient data, univariate and multivariate analyses were used to test predictors of occlusion and complications. DATA SYNTHESIS: We included 27 studies (484 aneurysms). The long-term adequate occlusion rate (O'Kelly-Marotta scale, C-D) was 82.7% (295/364; 95% CI, 77.4%-87.9%; I 2 ϭ 52%). Treatment-related complications were 12.5% (63/410; 95% CI, 9%-16%%; I 2 ϭ 18.8%), with 5.4% (29/418; 95% CI, 3.2%-7.5%; I 2 ϭ 0%) morbidity. MCA location was an independent factor associated with lower occlusion (OR ϭ 0.5, P ϭ .03) and higher complication rates (OR ϭ 1.8, P ϭ .02), compared with anterior communicating artery and distal anterior cerebral artery aneurysms. The Pipeline Embolization Device (versus other stents) gave better occlusion rates (OR ϭ 2.6, P ϭ .002), whereas large/giant aneurysms were associated with higher odds of complications (OR ϭ 2.2, P ϭ .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%; I 2 ϭ 4.2%) and 23.8% (69/283; 95% CI, 15.7%-32%; I 2 ϭ 80%), respectively. Symptoms related to occlusion and narrowing of the jailed arteries were 3.5% (6/269; 95% CI, 1.1%-5%; I 2 ϭ 0%) and 3% (6/245; 95% CI, 1%-4%; I 2 ϭ 0%), respectively. LIMITATIONS: We reviewed small and retrospective series. CONCLUSIONS: Flow diversion among distal anterior circulation aneurysms is effective, leading to adequate aneurysm occlusion in 83% of cases. However, this strategy has some limitations among MCA and larger lesions, especially related to the higher rate of complications. Compared with the other devices, the Pipeline Embolization Device seems to be associated with a higher occlusion rate.

Review of current intracranial aneurysm flow diversion technology and clinical use

“…56 Previous authors have recommended to slightly oversize FD selection for highly tortuous vessels to account for device foreshortening 44 ; however, this can lead to lengthening of the FD, decreasing its metal coverage and increasing porosity, thus decreasing its effectiveness. This was observed in a meta-analysis by Cagnazzo et al for distal aneurysms using previous generations of FDs, in which a higher occlusion trend was observed with the use of multiple FD than single FD in 484 treated aneurysms (OR 2.3, 95% CI 0.8 to 7.2; p=0.08), 55 likely associated with device oversizing.…”

“…The small size of parent vessels (diameter ≤3 mm) and the presence of important divisions and branches represent a risk for ischemic complications when using FD. 38 53 54 Although promising results have been observed with the use of FD in distal aneurysms with occlusion rates up to 82%, 55 clinical and technical complications still exist. In a single center experience, 8.3% of patients developed postoperative ischemic stroke following PED placement in the A1 segment.…”

Iatrogenic pericallosal artery aneurysm after endovascular procedure

“…In our case, endovascular stent-assisted coiling allowed safe exclusion of pericallosal dissecting aneurysm from circulation, and the implanted stent enabled reconstruction of the parent artery, restoring the normal lumen diameter. The second considered endovascular treatment option was implantation of a flow-diverted stent into the pericallosal artery [ 8 , 9 ]. However, we found this method to be riskier, causing more potential complications due to the need to use greater force to deliver a larger microcatheter and flow diverter stent into the pericallosal artery with coexisting artery stenosis and not completely cured ACoA aneurysm.…”

The p48 MW flow modulation device for treatment of unruptured, saccular intracranial aneurysms: a single center experience from 77 consecutive aneurysms

“…The authors reported a procedural complication rate of 7.7% and 95% rate of good clinical outcome among 60 patients with available clinical follow-ups. Two systematic reviews and meta-analyses reported the feasibility and high efficacy of FDS for the treatment of aneurysms on small or distal vessels but with non-negligible complication rate (Cagnazzo et al, 2019 ; Yan et al, 2018 ). The results of these systematic reviews are, however, limited by the selection and publication bias of the included studies.…”

“…Flow diverter stents (FDS) are now important tools in the neurointerventional armamentarium expanding the spectrum of treatable aneurysms by endovascular means. Although initially developed for the treatment of side-wall aneurysms of the internal carotid artery (ICA), their use has been increasingly expanding to include lesions involving smaller and more distal vessels, bifurcation aneurysms and also for treatment of challenging pathologies such as dissecting, fusiform, and blood-blister aneurysms (Puri et al, 2016 ; Cagnazzo et al, 2019 ; Bhogal et al, 2018 ; Saleme et al, 2014 ; Gawlitza et al, 2016 ; Rouchaud et al, 2015 ; Bhogal et al, 2017 ; Limbucci et al, 2020 ). This expansion of the spectrum of treatable lesions was invariably associated with the need for technical improvement of FDS such as better navigability, lower profile and the compatibility with small microcatheters to enable better and safer distal navigation.…”