Interventional Versus Medical Management of Infectious Intracranial Aneurysms

Infectious intracranial aneurysms (IIAs) are rare vascular lesions carrying high risks of rupture, intracranial hemorrhage, and mortality. Their low incidence and the absence of randomized controlled trials leave the optimal management strategy uncertain.

To systematically review and synthesize comparative observational evidence on interventional (surgical or endovascular) versus medical management of IIAs.

PubMed, Embase, and the Cochrane Library were searched from inception to August 4, 2025, using controlled vocabulary and free-text terms. Reference lists of relevant reviews and included articles were manually screened.

Comparative observational cohort studies reporting outcomes between at least one interventional strategy (surgical or endovascular) and medical management alone in patients with IIAs were included. Case reports, small case series without a comparator group, conference abstracts, and review articles were excluded.

Comparative outcomes were synthesized using random-effects pairwise meta-analysis. Effect estimates were expressed as risk ratios (RRs) with 95% confidence intervals. Heterogeneity was assessed using Cochran's Q test and the I² statistic. Sensitivity analyses were conducted using leave-one-out methods. Risk of bias was assessed with ROBINS-I; certainty of evidence was evaluated using the GRADE framework.

Thirteen retrospective observational studies (748 patients) were included. Interventional management was associated with higher treatment success (RR 1.36; 95% CI 1.13-1.65), lower mortality (RR 0.56; 0.36-0.88), fewer overall complications (RR 0.28; 0.13-0.59), and lower rupture/re-rupture risk (RR 0.42; 0.22-0.79). Recurrence, aneurysm enlargement, and permanent neurological deficits were infrequently reported and characterized by substantial imprecision. Most studies carried moderate or serious risk of bias, primarily due to confounding and non-randomized treatment allocation.

All included studies were retrospective and non-randomized, with substantial confounding by indication. Individual-patient data were unavailable, precluding adjusted or subgroup analyses. Outcome definitions and follow-up durations were inconsistently reported across studies. Publication bias cannot be excluded.

In observational cohorts, interventional management of IIAs was consistently associated with more favorable short-term clinical and angiographic outcomes compared with medical management alone. However, substantial risk of bias and confounding by indication limit these findings, which do not support causal inference and should be regarded as hypothesis-generating.