Delayed aneurysm rupture after flow-diverter deployment in unruptured aneurysms: a systematic review and meta-analysis

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.