Thrombus formation in aortic endografts

Purpose: To examine the incidence of intraprosthetic thrombotic deposits in aortic endografts. Methods: Transfemoral implantation of tube or bifurcated stent-grafts was p erformed in 82 patients (75 men; average age 67.7 years, range 25-88) for t reatment of aneurysms of the abdominal (n=73) or thoracic (n=9) aorta in a 3.5-year period. Patients underwent 3-phase helical computed tomographic (C T) examinations at 3-month intervals. The length and cross-sectional area o f any thrombotic deposits were measured from axial and 3-dimensional CT ima ges. Results: Over a 12.1-month mean follow-up, intraluminal deposits of thrombo tic material were observed in 19 (23.2%) patients, all with infrarenal endo grafts that were predominately of a bifurcated design. The first signs of t hrombus formation occurred on average 7 months postoperatively (range 1 wee k to 20 months). In 16 patients, nonocclusive deposits of thrombotic materi al were seen in the aortic segment of the endograft; a graft limb was invol ved in 5 patients. Three graft limbs occluded owing to kinking; no thrombus was seen on CT scans taken prior to occlusion. In 3 cases the thrombotic d eposits disappeared completely from the prosthesis lumen during follow-up. Conclusions: Based on this small experience, nearly 1 in 5 patients may exp erience some degree of intraluminal thrombus following endovascular treatme nt of aortic aneurysms. Whether the deposition of thrombus is influenced by the geometry of the aortic stent-graft or by flow conditions within the pr osthetic lumen must be determined in future studies.