Pressure-controlled active CSF irrigation versus non-pressure-controlled management following aneurysmal subarachnoid hemorrhage: a systematic review and comparative meta-analysis of DCI and safety outcomes.

Delayed cerebral infarction (DCI) is a major cause of poor outcome after aneurysmal subarachnoid hemorrhage (aSAH) and is closely associated with intracranial blood burden. Pressure-controlled cerebrospinal fluid (CSF) irrigation techniques have been developed to actively accelerate blood clearance; however, their overall clinical effectiveness and safety profile have not been comprehensively evaluated in a comparative framework. Accordingly, we performed a systematic synthesis of the available evidence focusing on both clinical efficacy and treatment-related safety outcomes. A systematic review and meta-analysis were conducted in accordance with PRISMA guidelines to evaluate both safety and efficacy. PubMed/MEDLINE, Embase, and Scopus were searched from inception through October 15, 2025. Studies comparing pressure-controlled active CSF irrigation techniques (including stereotactic ventriculocisternostomy, cisterno-ventricular catheter systems, ventriculo-lumbar irrigation, and lumbo-lumbar irrigation) with non-pressure-controlled management were included. The primary radiographic outcome was delayed cerebral infarction. Secondary outcomes captured both additional efficacy endpoints and safety, including symptomatic vasospasm, in-hospital mortality, functional outcome, and procedure-related complications. Arm-specific outcome prevalences were pooled descriptively using random-effects models, while comparative treatment effects were synthesized as odds ratios from direct within-study comparisons between pressure-controlled and non-pressure-controlled management. Risk of bias was assessed using ROBINS-I and RoB 2. Nine studies comprising 2,033 patients were included; most evidence was observational and at serious risk of confounding. In direct within-study comparative meta-analyses, pressure-controlled irrigation was associated with lower odds of delayed cerebral infarction (OR 0.36, 95% CI 0.25-0.50), symptomatic vasospasm (OR 0.48, 95% CI 0.27-0.88), and imaging-defined vasospasm (OR 0.33, 95% CI 0.23-0.48). No statistically significant associations were observed for angiographic vasospasm (OR 0.59, 95% CI 0.30-1.17), in-hospital mortality (OR 1.19, 95% CI 0.83-1.69), shunt-dependent hydrocephalus (OR 1.03, 95% CI 0.48-2.22), or infectious complications (OR 0.75, 95% CI 0.46-1.21). Catheter-related hemorrhage was rare in descriptive intervention-group data, but adequate comparative analysis was unavailable. Comparative functional outcome analysis was not feasible because mRS data were insufficiently reported in non-pressure-controlled comparator arms. Direct comparative analyses showed no observed heterogeneity (I² = 0%), whereas descriptive prevalence estimates were substantially heterogeneous. Pressure-controlled active CSF irrigation was associated with lower odds of delayed cerebral infarction and symptomatic and imaging-defined vasospasm after aSAH. Effects on angiographic vasospasm, mortality, safety outcomes, and functional recovery remain uncertain. Interpretation is limited by predominantly nonrandomized evidence and residual confounding. Multicenter randomized trials are required to confirm comparative effectiveness and identify appropriate patients.