Impact of intervention timing on outcomes in aneurysmal subarachnoid hemorrhage: a systematic review and meta-analysis of surgical, endovascular, and pharmacological strategies in 3069 patients

Abstract Background Aneurysmal subarachnoid hemorrhage (aSAH) is a devastating neurological emergency with high mortality and disability rates. The optimal timing for interventions (surgical clipping, endovascular coiling, decompressive craniectomy, and tranexamic acid [TXA]) remains controversial, with conflicting evidence on early (≤ 72 h) versus delayed (> 72 h) treatment strategies. This systematic review and meta-analysis evaluates the impact of intervention timing on mortality, rebleeding, functional outcomes, and complications in aSAH patients. Methods Following PRISMA guidelines, we analyzed seven studies (n = 3069 patients) from PubMed, Embase, and Cochrane CENTRAL (2002–2024). Included studies compared early (≤ 72 h) versus delayed (> 72 h) interventions. Primary outcomes were mortality and rebleeding; secondary outcomes included functional recovery (modified Rankin Scale [mRS]/Glasgow Outcome Scale [GOS]), vasospasm, infarction, and shunt dependency. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using random-effects models. Results Early intervention was associated with lower mortality (OR 0.66, 95% CI 0.47–0.93, p = 0.02), with clipping most effective within 48 h or after 7 days, although the observed effect reflected a pooled time-dependent association across heterogeneous intervention modalities rather than a unified treatment effect. Endovascular coiling within 24 h improved survival in poor-grade patients (OR 0.39, 95% CI 0.13–1.12). Early decompressive craniectomy (≤ 24 h) lowered mortality by 12% ( p = 0.031). TXA reduced rebleeding (2.4% vs. 10.8%, p < 0.01) but did not improve functional outcomes ( p = 0.78). Early clipping increased procedural infarction risk (24% vs. 8.7%, p = 0.003), while vasospasm rates were unaffected by timing. Functional recovery favoured early intervention (OR 1.77, 95% CI 1.02–3.05, p = 0.04). Conclusion Early intervention within 72 h after aneurysmal subarachnoid hemorrhage was associated with lower mortality and improved functional outcomes, with effects varying by intervention modality. Endovascular coiling and decompressive craniectomy showed the most consistent early survival benefit, particularly in poor-grade patients, whereas surgical clipping demonstrated a time-dependent U-shaped risk profile. Ultra-early TXA reduced rebleeding without improving long-term functional outcomes. Given substantial heterogeneity in intervention types, timing definitions, and study designs, these findings should be interpreted as associative rather than definitive or prescriptive.