Endovascular Treatment for Thoracoabdominal Aortic Aneurysm and Complex Abdominal Aortic Aneurysm Using Fenestrated and Branched Grafts

Abstract

Fenestrated and branched endovascular aneurysm repair (F/B-EVAR) is a less invasive treatment for thoracoabdominal aortic aneurysm (TAAA) and complex abdominal aortic aneurysm. Fenestrated and branched (cuff) grafts facilitate safe and durable repair, and bail-out maneuvers for target vessel cannulation and stenting have been established; however, the available bridging stent grafts have differences. The present article discusses the optimal selection of fenestrated or branched grafts, the cannulation of target vessels that have difficult anatomies, and the advantages and disadvantages of various bridging stents. We review the causes and risk factors of spinal cord injury (SCI), the protocol for prevention of SCI, and the outcomes of target vessel stent grafting, including patency and endoleak. Although conventional open surgery is the gold standard for the repair of thoracoabdominal aortic aneurysm (TAAA), it is highly invasive. To reduce invasiveness, hybrid surgery that combines open surgery and endovascular therapy has been developed [1, 2], and fenestrated and branched endovascular aneurysm repair (F/B-EVAR) is frequently performed at centers in the USA, Europe, and Japan [3-5]. Additionally, a hostile neck may be an independent factor for sac enlargement after EVAR for abdominal aortic aneurysm (AAA) [6], but a previous study reported that 41% of AAA cases presented with neck lengths outside the range prescribed by the traditional instruction for use [7]. Stark et al. showed that extending the graft above the highest renal artery would create an augmented neck length in 90% of patients with AAA [7]. F/B-EVAR is based on this principle. However, there are some technical tips for, and limitations of, fenestrated and/or branched graft. F/B-EVAR for TAAA and complex AAA will be reviewed in the present article.