Treating the paravisceral aorta with parallel endografts (chimneys and snorkels).

While excellent results can be achieved with the open repair of juxtarenal and suprarenal aortic aneurysms in good-risk patients, the outcomes in high-risk patients are less favorable. The use of standard infrarenal endografts to treat these patients has been limited due to the absence of a suitable proximal landing zone. Using infrarenal endografts outside the instructions for use has been shown to lead to poorer outcomes with a higher incidence of type I endoleaks and graft migration. Fenestrated and branched endografts are viable options, but until recently have not been commercially available within the United States. In addition, they require meticulous preoperative planning and 4 to 6 weeks to manufacture. This makes them unsuitable for use in the urgent setting. Others have looked at the use of parallel covered stents placed alongside the main endograft body, the "chimney" or "snorkel" graft technique, to allow for continued perfusion to visceral/renal vessels. This technique allows for proximal placement of the landing zone of the main body, while maintaining blood flow to critical branches. The purpose of this article is to review the current literature on chimney grafts, their efficacy, and associated morbidity and mortality.