Aneurysmal degeneration of a saphenous vein graft following the repair of a popliteal aneurysm: case report and literature review.

True aneurysm formation in arterialized autologous veins is an unusual complication. A saccular aneurysmal degeneration of 53 mm (maximal diameter) of a saphenous vein graft inserted for repair of a popliteal aneurysm, four years after implantation, is reported. The patient (with prior history of abdominal aortic aneurysm) had been initially treated through a posterior approach. A new saphenous vein bypass grafting (medial approach) was performed. Histological examination revealed myointimal fibrosis, medial degeneration and inflammation. In spite of the widespread use of the autologous saphenous vein as an arterial substitute, this complication is extremely rare and its etiology remains unclear. Atherosclerosis is considered to be the main cause of aneurysm formation in vein grafts, but current data suggest that additional etiopathogenic factors should be further investigated. We note the rarity of this finding and review the literature for true aneurysm formation within vein grafts used for bypass procedures.