Types of Endoleaks

Blood flow into the aneurysm sac following endovascular repair can be classified as:

• Type I (seal failure): Blood flow is due to ineffective seal with the native vessel at the proximal (IA) or distal (IB) end of the graft. Usually occur early. A Type I endoleak is repaired immediately.
• Type II (retrograde flow): Blood is from retrograde from small vessels, such as lumbar arteries or the inferior mesenteric artery. Delayed images are sometimes needed, Most have a benign course, but increasing sac size is of concern. Management depends on the surgeon. Some follow the aneurysm and intervene if it increases, while others choose to intervene.
• Type III (defect): Rare. Blood flow due to ineffective sealing of overlapping grafts (IIIA) or rupture of the graft (IIIB). Usually occurs early due to technical issues. Late cases occur due to device breakdown. Associated with a sudden elevation of intrasac pressure. A Type III endoleak is repaired immediately.
• Type IV (porosity): Rare. Blood flow is due to porosity of the graft. No treatment is usually indicated as these resolve within a month.
• Type V (endotension): The exact cause of these is unknown.

References

• Agarwal PP, Chughtai A, Matzinger FR, Kazerooni EA. Multidetector CT of thoracic aortic aneurysms. Radiographics. 2009 Mar-Apr;29(2):537-52.
• Stavropoulos SW, Charagundla SR. Imaging techniques for detection and management of endoleaks after endovascular aortic aneurysm repair. Radiology. 2007 Jun;243(3):641-55.