De Toledo, Otavio Frederico

Background Delayed aneurysm rupture (DAR) is a potentially devastating complication after flow-diverters (FD) deployment and their exact mechanisms are still unclear. The purpose of this meta-analysis is to synthesize the latest evidence on DAR after FD treatment and identify predictive factors. Methods A systematic review and meta-analysis were conducted according to established protocols. Searches were conducted in PubMed, Scopus, Web of Science, and Embase databases up to June 2024 using variations of “aneurysm “and “delayed aneurysm rupture” terms. Original studies reporting DAR and including more than five patients were included. All analyses were conducted in R software (version 4.4.2), employing the “meta” and “tableone” packages. Results 64 studies with 9820 patients were included, large aneurysm size (OR=1.08, 95% CI (1.02, 1.14), P value=0.008), intra-aneurysmal thrombus (OR=1.05, 95% CI (1.01, 1.09), P value=0.010) and posterior circulation location (OR=1.02, 95% CI (1.00, 1.04), P value=0.014) were significant risk factors for DAR. The pooled prevalence of DAR was 1.40%, with a rate of 1.18% after removing outliers. DAR occurred within 30 days in 66.7% of cases, with a mortality rate of 73.3% at discharge. Conclusion DAR following flow diversion treatment is an uncommon but devastating complication and remains a limitation of the technique. It is influenced by factors such as large aneurysm size, intra-aneurysmal thrombosis, and posterior circulation involvement. The first 30 days post-procedure represent a particularly high-risk period. Despite advancements in FD technology, significant gaps remain, highlighting the need for further research to improve risk assessment and treatment strategies.

Background The pipeline embolization device (PED) has been increasingly used to treat brain aneurysms; however, concerns have been raised about braid stability with newer drawn filled tubing technology devices. Objective To evaluate braid stability of PED early generations using data from the PREMIER trial. Methods All consecutive intracranial aneurysms treated with PED (Classic and Flex) within the PREMIER trial were reviewed for braid stability (fish mouthing, foreshortening, braid bump, braid collapsing). Immediate postprocedure cone-beam CT and angiography were compared with 1- and 2- years' follow-up. Analyses included safety, measured with the modified Rankin Scale (mRS) score, including +1 mRS point and a good clinical outcome (mRS score 0–2), vessel stenosis ≥50%, effectiveness measured with Raymond-Roy Scale, and re-treatment rates. Results 133/141 aneurysms had a complete dataset. 8/133 (6%) aneurysms showed braid deformations. Inter-reader agreement was excellent (κ=0.83). Braid deformations were statistically significantly associated with in-stent vessel stenosis >50% (P=0.029), without impact on effectiveness or safety. Fish mouthing was found in 1/133 (0.75%) at 1 year, causing >50% vessel stenosis. Foreshortening occurred in 6/133 (4.5%), and braid bump in 1/133 (0.75%) associated with severe in-stent stenosis. Four other cases (3.0%) of asymptomatic in-stent stenosis due to neointimal hyperplasia were seen without braid changes. No new braid stability deformations were found at the 2-year follow-up. Conclusion Our study demonstrates excellent braid stability among patients treated with the PED Classic and Flex in the PREMIER trial. Within the uncommon braid changes observed, none affected the PED safety or efficacy. Trial registration number NCT02186561 .