ChEVAS: Exploring Off- the-Shelf Repair of Thoracoabdominal Aneurysms

E ndovascular aneurysm repair (EVAR) has revolutionized the treatment of abdominal aortic aneurysms (AAAs). EVAR’s advantages of lower perioperative morbidity and mortality compared with open repair are perhaps even more important when treating AAAs involving the visceral segment of the aorta.1-3 As such, having viable off-the-shelf device options for the endovascular treatment of these aneurysms is crucial in modern vascular surgery. The use of parallel or “chimney” grafts was first described in the context of salvaging aortic branch vessels that had been inadvertently or unavoidably covered during EVAR.4 More recently, chimney grafts have been used alongside aortic stent grafts to elongate the proposed sealing zone in the visceral segment of the aorta. They were first described in conjunction with conventional EVAR,5,6 and although the combination has been largely successful, there are concerns regarding gutters that may form between the aortic stent graft and the chimney grafts, potentially leading to the formation of type Ia endoleaks.7 Using chimney grafts in conjunction with an endovascular aneurysm sealing (EVAS) system (Nellix, Endologix) may reduce the risk of gutter endoleaks because the polymer-filled endobags can fill potential gutters between the main aortic endograft and the chimney grafts. In effect, this forms a motionless environment at the proximal seal zone after the polymer curing process is complete (Figure 1).8,9