Endovascular stent grafting in the presence of aortic neck filling defects: Early clinical experience

Objective: Although endovascular grafts have been increasingly applied to t he treatment of abdominal aortic aneurysms, their use in clinical trials is limited by well-defined anatomical exclusion criteria. One such criterion is the presence of thrombus within the infrarenal neck of an aneurysm, whic h is thought to (1) prevent the creation of a permanent watertight seal bet ween the graft and the vessel wall, resulting in an endoleak; (2) contribut e to stent migration; and (3) increase the risk of thromboembolism. This ar ticle summarizes our experience with. endovascular abdominal aortic aneurys m exclusion in 19 patients with large aortic aneurysms, significant medical comorbidities, and apparent thrombus extending into the pararenal aortic n eck. Methods: Of 268 patients undergoing abdominal aortic aneurysm repair, 19 (7 %; 17 men; mean age, 71 years) demonstrated computed tomographic and angiog raphic evidence of intramural filling defects at the level of the aortic ne ck. In no instance did these filling defects extend above the renal arterie s. Endovascular grafting was performed through use of a balloon-expandable Palmaz stent and an expanded polytetrafluoroethylene graft, delivered and d eployed under fluoroscopic guidance. Follow-up at 3, 6, and 12 months and a nnually thereafter was performed with computed tomography and duplex ultras ound scan. Results: Spiral computed tomography and aortography revealed an irregular f low-limiting defect, occupying up to 75% of the aortic circumference, in ev ery case. The mean aneurysm size, aortic neck diameter, and neck length bef ore the procedure were 6.1, 2.43, and 1.4 cm, respectively; the mean aortic neck diameter after the procedure was 2.61 cm. No primary endoleaks were o bserved after graft insertion, and no delayed endoleaks have been detected during follow-up, which ranged from 7 to 48 months (mean, 23 months). In on e patient, an asymptomatic renal artery embolus was detected on immediate f ollow-up computed tomography, and in another patient, an asymptomatic poste rior tibial embolus occurred. Conclusion: No primary endoleaks, endograft migration, or significant dista l embolization were observed after endografting in patients with aortic nec k thrombus. The deployment of the fenestrated portion of the stent, above t he thrombus and across the renal arteries, allows for effective renal perfu sion, graft fixation, and exclusion of potential mural thrombus from the ci rculation. The presence of aortic neck thrombus may not necessarily be a co ntraindication to endovascular repair in select patients.