In an almost 20-year evolution, parallel-graft techniques have emerged as part of the effort to rescue or preserve inadvertently excluded aortic branches during endograft aortic aneurysm repair. Currently, planned vessel-branch revascularization in complex pathologies, including aortic side branches, is more frequently cited as the main reason for their use. Simultaneously, persistent issues related to availability, sizing, procedural complexity, and cost of fenestrated endografts led to wide and expanded use of parallel grafts as a total endovascular solution to complex aortic diseases.

Multiple names have been given to these techniques, including chimneys, snorkels, CHIMPS, periscopes, and sandwich grafts. “Parallel grafts” should be considered as the all-encompassing term that best captures the one feature all branch-preserving conduits share—their intra-aortic parallel course, external to but alongside the main aortic endograft. However, use of the term chimney graft was preferred to popularize the technique worldwide.