[Rational radiologic after-care of endoluminal aortic bypass]

To identify essential and relevant diagnostic algorithms in the follow-up of stent-grafts placed for aortic dissections and aneurysms based on our 7 years experience including the use of more than 10 different devices.

Evaluation of conventional biplane imaging, angiography, sonography, CT and MR in the efficacy of demonstrating endoleaks, sac shrinkage, changes of stent-graft integrity and, with special reference to MR-compatibility of various stent-graft devices.

Endoleaks are found in 20-30% of patients after endovascular exclusion of abdominal aortic aneurysms. However, this rate neither necessarily reflects the clinical course nor the onset and course of sac shrinkage. Physical long-term integrity of the devices is seen best on conventional bi-plane radiographs. Sonography is helpful only in selected patients (non-obese, good compliance) otherwise not providing information precisely enough for sac control. As gold standard both CT (CTA) and MR (MRA) are equally effective in the follow-up of endovascular stent-grafts, allowing 3D control of sac geometry in aneurysmal disease or hemodynamic changes in stent-grafts for aortic dissection. MRI is considered to be more effective in the detection of small endoleaks. Angiography is inferior to CT and MRI in the diagnosis of endoleaks and thus is required only for intervention planning in patients with suspected endoleaks. Two of 8 evaluated stent-graft devices proved to be prohibitive for MRI because of their severe artifacts productions (Life-path, Zenith) as a result of their thick metallic meshwork.

CT including CTA with 2D and 3D reformatting is the method of choice for the follow up of stent-graft treatment of aortic disease. Depending on availability, MRI may be used alternatively. In young patients and for those with contraindications to iodinated contrast media MRI is a perfectly equivalent alternative. Especially in patients with known contraindications to iodinated contrast media the MR-compatibility should be taken into consideration in the choice of the endovascular device.