Lara-Velazquez, Montserrat

Abstract Stroke thrombi are heterogeneous; their composition influences their mechanical properties, including stiffness, elasticity, and adhesiveness, which in turn affect their response to therapy. Systemic characterization of the thrombi components could help select therapeutic techniques and anticipate outcomes. We conducted a systematic review and meta-analysis to evaluate associations between thrombi composition and angiographic and functional outcomes in acute ischemic stroke (AIS). Up to May 2025, relevant studies were sourced from four databases: PubMed, Web of Science, Scopus, and Embase. We included cohort studies whose populations are patients with AIS in relation to thrombi composition. Thirty-six studies involving 5,462 patients matched our eligibility criteria. Angiographic success (Thrombolysis in Cerebral Infarction ≥ 2b/3) did not differ significantly between red blood cell (RBC)-rich and fibrin-rich thrombi (risk ratio [RR] 1.02, 95% confidence interval [CI] 0.85–1.22; p = 0.84; I 2 = 63.8%; very low certainty). However, thrombi from patients with good angiographic outcomes had a significantly higher RBC content compared to patients with poor outcomes (mean difference = 7.22%, 95% CI 3.31–11.13; p < 0.001; low certainty). No significant difference was observed between RBC-rich and fibrin-rich thrombi regarding functional independence at 90 days (modified Rankin Scale 0–2) (RR = 1.22, 95% CI 0.73–2.05; p = 0.31; low certainty). While RBC-rich thrombi are associated with more favorable angiographic performance, thrombus composition alone does not predict functional outcomes. Stroke outcomes remain multifactorial, dominated by time to reperfusion, collateral circulation, and baseline severity. Preinterventional assessment of clot composition via imaging or biomarkers may support individualized therapy but should complement, not replace, other prognostic determinants.

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.