Isolated Iliac Artery Aneurysm: A Narrative Review of Natural History and Treatment in the Era of Iliac Branch Devices.

Isolated iliac artery aneurysm-defined as aneurysmal dilatation of the common, internal, or external iliac artery without a concurrent abdominal aortic aneurysm requiring simultaneous repair-accounts for approximately 2%-7% of intra-abdominal aneurysms. This narrative review examines its natural history and the relative merits of open and endovascular treatment, with particular attention to internal iliac artery management, drawing on literature published since 2007. Two features deserve greater attention. First, much of what is cited as evidence on isolated disease derives from mixed aorto-iliac cohorts: across 7 such series, isolated aneurysms accounted for 120 of 897 patients (13.4%). Second, the frequently repeated claim that Japanese patients experience rupture at smaller diameters rests on comparisons between treated referral cohorts and Western imaging-surveillance cohorts, whose denominators are not equivalent. Reported growth rates range from 0.2 to 1.6 mm/year and accelerate with increasing diameter. Endovascular repair offers consistent perioperative advantages, whereas open repair may prove more durable when internal iliac artery sacrifice would otherwise be required. Although iliac branch devices are widely used in clinical practice, only 97 patients with truly isolated disease have been reported in dedicated series. The positions on treatment thresholds and techniques presented in this review are therefore identified as the author's opinions.