Rodriguez‐Erazú, Fernanda

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 AND OBJECTIVES: Embolization is part of multidisciplinary brain arteriovenous malformations (AVMs) treatment, yet safety data for novel liquid embolization agents (LEAs) such as Squid and PHIL remain limited. This study reports complications and outcomes from curative embolization using Onyx, Squid, PHIL, and Glue. METHODS: Adult patients with brain AVMs treated with LEAs from July 2015 to December 2022 were reviewed for intraprocedural technical issues, postoperative hemorrhagic, and ischemic complications. Minor (modified Rankin Scale ≤2) and major complication rate (morbidity/modified Rankin Scale >2), mortality, and 6-month angiographic cure rate were evaluated. RESULTS: In total, 135 patients (62.2% male, mean age 41.7 ± 15.1 years) with 206 embolizations (34% Onyx, 18.9% Squid, 17.5% PHIL, 28.2% Glue) were included. Overall, 87.4% procedures were in ruptured AVMs and 84% treated by the transarterial technique (84%). The 6-month angiographic cure rate was 53.3%, higher when nonadhesive LEAs were used than Glue (65.3% vs 17.6%, P < .001). In adjusted analysis, only eloquent location (odds ratio [OR] = 4.4; P = .007) and Glue (OR = 9.1; 95% CI 2.9-28.9, P < .001) were predictors of lower angiographic occlusion rate, whereas size had an inverse correlation (OR = 0.67; P = .019). Technical procedural complications, hemorrhagic, and ischemic rates were 10.2% (2.2% morbidity), 13.1% (3.7% morbidity and 2.2% mortality), and 9.2% (2.2% morbidity, 0% mortality), respectively, regardless of the preferred LEA. Minor, major complications, and mortality rates were 3.7%, 4.4%, and 2.2%, respectively. Hemorrhage was the major contributor to morbidity and mortality, whereas deep venous drainage was an independent predictor of hemorrhage and mortality. CONCLUSION: PHIL and Squid demonstrated complication and angiographic cure rates comparable with Onyx. However, curative embolization of brain AVMs resulted in only moderate angiographic occlusion. Larger multicenter studies with standardized operator protocols, cost-effectiveness assessments, and extended follow-up are warranted to validate these findings.

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 .

Background Although flow diverters (FDs) have benefited from several technical improvements, recently concerns have arisen regarding the braid stability after implantation. Thus, we investigated frequency, predictive factors, and clinical impact of the phenomenon of FD braid deformation (FDBD). Methods Consecutive intracranial aneurysms (IAs) treated with various FDs, between January 2018 and July 2023, were reviewed to identify FDBD (defined as the deformation of a FD without any external force applied to it). Patient, aneurysm, procedural, and FD characteristics were retrieved and analyzed using univariate and multivariable analyses. Morbidity is defined as a score of +1 in the modified Rankin Scale at 3 months. Results In total, 245 FD procedures (271 FDs implanted; 25 multiple IAs treated with 1 FD) in 228 patients; FDBD was observed in 36/245 cases (14.7%), mainly at follow-up angiography (32/36, 88.9%); fish-mouthing was the most frequent FDBD. Morbidity was related to fish-mouthing and braid collapse and was significantly higher in the FDBD group after retreatment (p=0.04). Drawn filled tubing with platinum (DFT) (adjusted odds ratio (aOR)=7.0, 95% CI 3.0 to 17.5; p<0.001) and FD diameter (aOR=2.2, 95% CI 1.3 to 4.1; p<0.01) were identified as independent predictors of FDBD. The metal alloy composing the FD (p=0.13) and coated surfaces were not significantly associated with FDBD (p=0.54 in multivariable analysis). Conclusions FDBD is a frequent phenomenon observed in about 15% of cases, and it was responsible for higher morbidity. Only FD characteristics (DFT and FD diameter) were independent determinants of FDBD. Future research should focus on the impact of novel braid configurations and materials on braid stability.

Background Sealing of the aneurysm neck with a Woven EndoBridge (WEB) device is recommended for disrupting the blood flow inside the aneurysm. This study investigates the relationship between WEB neck apposition and aneurysm occlusion rates. Methods Aneurysms treated with a WEB from March 2017 to May 2022 at a single center were included. WEB neck apposition (poor/good) and WEB protrusion (yes/no) were evaluated on post-detachment high resolution cone beam CT images. Angiographic occlusion was assessed with the Bicêtre Occlusion Scale score (BOSS). Univariate and multivariable analysis tested the association between neck apposition and occlusion rates. Results The study included 159 aneurysms in 141 patients (mean age 55.8±11.2 years; 64.2% women). Good neck apposition and protrusion were noted in 123 (77.4%) and 30 (18.9%) cases, respectively. Inter-rater agreements were good for neck apposition (κ=0.75) and protrusion (κ=0.78). Complete and adequate occlusion was achieved in 104 (65%) and 130 (82%) cases, respectively (median follow-up 18 months). Good neck apposition was a strong independent predictor for both adequate (adjusted OR (aOR)=5.9, 95% CI 2.4 to 14.9; P<0.001) and complete occlusion (aOR=7.1, 95% CI 3.0 to 18.1; P<0.001). Protrusion was more frequent in the adequate occlusion group versus the aneurysm recurrence group without reaching statistical significance (P=0.06), but was associated with more thromboembolic complications (9/30 (30%) vs 12/129 (9%); P<0.01). WEB shape modification was significantly greater in poor apposition cases (P=0.03). Conclusions Achieving good neck apposition of the WEB strongly predicts aneurysm occlusion during follow-up. WEB protrusion should be minimized due to the increase in thromboembolic risk with limited impact on aneurysm occlusion.