Abdominal aortic aneurysm is operated when the size is more than:

Ref. Sabiston Textbook of Surgery. Pg. 1723   INDICATIONS FOR OPERATION Asymptomatic – Aneursym  >55mm in anteroposterior diameter. Patient fit for surgery (expected mortality rate <5%) Indications for endoluminal operation are the same as for open operation . Symptomatic . Aneursym of any size that is painful or tender Aneursym of any size that is causing distal embolisation . Indications are wider than for an asymptomatic lesion (expected mortality rate 5-20%)