The rebleeding risk for ruptured, unsecured aneurysms is around 12%; most rebleeding occurs within 24 h [74]—acknowledging heterogeneity in the timing of aneurysm securement and definition of rebleeding. Elevated systolic blood pressure (SBP), particularly above 160 mmHg [74], poorer clinical (i.e., higher World Federation of Neurosurgical Societies (WFNS) and Hunt-Hess grades) and radiological grades, and aneurysm characteristics are associated with a higher risk [75, 76].