Abstract
Small unruptured aneurysms (SUAs) are generally considered to be at a low risk of rupture and subsequent subarachnoid hemorrhage. However, they are considered high risk if they have an irregular shape, an associated bleb is present, or they are located at a critical site such as the anterior communicating artery or internal carotid-posterior communicating artery. In addition, patients with SUAs often choose surgery owing to extreme anxiety regarding rupture, or severe restriction of activities of daily living. Stroke physicians have not yet reached a consensus regarding surgical indications for patients with SUAs concerned about such occurrences. The annual crude death rate in men is 3.4% at 75 to 79 years and 6.3% at 80 to 84 years, and rapidly increasing thereafter. Considering patients with unruptured aneurysms who visit our outpatient services and receive non-surgical treatment, 132 of 172 aneurysms (77%) were less than 5 mm in diameter, and the persistence rate at subsequent patient visits was 82% at 60 months and 62% at 120 months, with a low rupture rate (0.5%/year). Clinicians need to be cautious when explaining the risks of SUAs, and consider preemptive surgery for asymptomatic SUAs in the elderly, even if treated using minimally invasive procedures. We should reconsider strategies for management of asymptomatic SUAs based on the crude death rate and evidence of cause of death in long-term observational cohorts. Assuming shared decision-making between the medical staff and patients, risk control with medical care and follow-up by MRI are equally feasible options as the treatment of choice for unruptured aneurysms as surgery, especially for elderly patients with SUAs. Stroke physicians and neurosurgeons who are not involved in surgery might be eligible for patient care and long-term follow-up of SUAs. Studies focusing on medical management of such patients should be conducted.
