After an endoluminal graft repair all bloodflow is ideally excluded from the AAA allowing thrombosis of the AAA outside of the stent graft. An endoleak is an area of the AAA that has been excluded by the endoluminal graft that nonetheless continues to have bloodflow. With an endoleak a treated aneurysm may continue to grow and eventually rupture. Signs of an endoleak can include flow seen outside the graft lumen or an increasing size of the aneurysm post repair. However, ultrasound is not sensitive and the signs can be subtle. Pulsatility of the sac reduces post repair, but still occurs even without an endoleak.

A contrast enhanced multiphase CT examination is used to diagnose the specific type of endoleak and should be the initial choice of investigation if a postoperative complication is suspected. There are 4 types of endoleaks of which two require immediate treatment when diagnosed. Endoleaks occur in approximately a third of AAA’s treated with endoluminal grafts and generally patients have yearly routine imaging surveillance.