Planned exploratory analyses of DCI and favourable outcomes will include multivariate logistic regression using presentation SAH grade, age and the presence or absence of immediate post-procedural neurological deficits as the key covariates. Additional exploratory analyses with similar multivariate logistic regressions are planned, with the extra post-randomisation variables of the development of hydrocephalus, timing of hydrocephalus treatment and timing of aneurysm treatment.