Histopathologic analysis of endovascular stent grafts from patients with aortic aneurysms: Does healing occur?

A, Preoperative aortic arch angiogram of an 83-year-old man with isolated descending thoracic aortic aneurysm. B, An Excluder device constructed from extended polytetrafluoroethylene (ePTFE) and nitinol metal wire. C, A computed tomography scan obtained postoperatively demonstrates successful aneurysm exclusion with contrast confined to endograft. D, The patient died 6 months later of myocardial infarction. During autopsy, intact aorta was removed en bloc. E, A window was created at site of proximal graft fixation. Note absence of intimal pannus across stent to artery interface at proximal attachment site. F, Light micrograph of endograft of cross section at level of proximal anastomosis. Two separate layers of ePTFE consistent with fabrication of the Excluder endograft can be identified. Compacted fibrin on luminal surface comprises the neointima.

A, En bloc aorta specimen from an 81-year-old man after endovascular repair of infrarenal abdominal aortic aneurysm. Aorto-uni-iliac device is seen within explanted aorta after successful aneurysm exclusion. He died on fourth postoperative day of acute myocardial infarction. B, Light micrograph of section through midportion of graft contains thick uniform layer of fibrin.

Electron microscopy performed on aortic endograft explanted 2 months after aortic endografting. Nodal pattern of ePTFE graft material is seen with adherent platelets and fibrin, but no organized cellular layer.