Endovascular treatment of intracranial aneurysms: current status.

In a recent systematic review and meta-analysis, the overall prevalence of unruptured intracranial aneurysms (IAs) is estimated as 3.2%.1 The prevalence of IAs is higher in patients with autosomal dominant polycystic kidney disease or a positive family history of IAs of subarachnoid hemorrhage (SAH).1 From the same review, the size of unruptured IAs is <5 mm in 66%, 5 to 9 mm in 27%, and ≥10 mm in 7%; the site of IAs is internal carotid artery, including posterior communicating artery in 42%, middle cerebral artery in 35%, and anterior cerebral artery and anterior communicating artery in 18%. Most IAs are clinically silent until rupture, which is unpredictable and sometimes associated with SAH, intraparenchymal hematoma, and an intraventricular hemorrhage. The case fatality of IA rupture is high (from 27% to 44%), but has decreased during the past 3 decades because of the introduction of improved management strategies, including neurocritical care.2 The International Study of Unruptured Intracranial Aneurysms (ISUIA) showed an increased risk of IA rupture with aneurysm size and for posterior circulation aneurysms.3 Although treatment of a ruptured aneurysm is accepted as an emergency, indication for treatment of unruptured IAs is still being discussed. Decision for treatment is based on clinical and anatomic factors; among them, the most important being patient’s age, family history of IA(s), associated conditions (autosomal dominant polycystic kidney disease), symptomatic aneurysms, aneurysm size, and location. The randomized International Subarachnoid Aneurysm Trial (ISAT) study has clearly demonstrated the superiority of endovascular treatment (EVT) of ruptured aneurysms using coil technology over surgery.4 Since the publication of these results, EVT has rapidly evolved. Although for unruptured aneurysms a direct comparison between EVT and surgery is not available, EVT has been widely used in this subgroup as well.5 In fact the population presenting with …