Rapid Documented Growth of Aneurysm Bleb Led to Rupture of an Incidental Intracranial Anterior Communicating Artery Aneurysm

Background A major challenge in the management of patients with unruptured intracranial aneurysms (UIAs) is to identify criteria indicating a higher risk of future UIA rupture. We report a rare patient with documented short-term bleb growth of an UIA followed by a fatal aneurysm rupture supporting the high risk of rupture of short-term shape changes in UIAs. Case Description A 72-year-old man with an incidental unruptured anterior communicating artery aneurysm of 9 mm showed a bleb growth on the aneurysm sac at 6-week follow-up computed tomography angiography (CTA). Aneurysm treatment was recommended by the interdisciplinary board (PHASES score: 9 points; rupture risk 4.3% in 5 years). The patient wanted to discuss the treatment plan with his family before making a final decision. Two days after the CTA showing bleb growth, he was admitted emergently with a severe subarachnoid hemorrhage (SAH) (World Federation of Neurologic Surgeons grade 5; Fisher 3). The aneurysm was occluded with coils. However, the patient died on day 14 after SAH due to delayed ischemic neurologic deficits and multiple organ failure. Conclusions This case illustrates the high rupture risk of an UIA presenting a documented growth of an aneurysm bleb over a short follow-up time. In retrospect, this patient might have benefited from emergent aneurysm occlusion. The interest of this report comes from the proof that aneurysmal bleb growth constitutes a high risk for short-term aneurysm rupture.