Introduction

Fenestrated-branched endovascular aortic repair (F-BEVAR) has rapidly developed since the 1990s. The first fenestrated repair was performed in 1996 by Park, using a modified device with a single fenestration to incorporate an accessory renal artery for infrarenal abdominal aortic aneurysm (AAA) [1]. A year later, a research team in Perth, Australia, led by Tom Browne, Michael Lawrence-Browne, and David Hartley, also demonstrated target-vessel preservation in an animal model with a single fenestration. In 1998, Dr. John Anderson performed the first clinical fenestrated repair for a juxtarenal AAA in Adelaide, Australia, without placement of an aligning stent. Anderson later partnered with the research team from Perth, adding a balloon-expandable stent to the technique in order to fix the fenestration to the target-vessel orifice [2]. The technology rapidly spread through Australia, Asia, and Europe, before it was adopted and subsequently popularized in the United States by Roy Greenberg [3]. The technology was first applied to thoracoabdominal aortic aneurysms (TAAA) by Michael Denton, with incorporation of the celiac axis (CA) and superior mesenteric artery (SMA) [1].

Many adjuncts and improvements have been added to the technique, including nitinol rings for reinforcement of the fenestrations, radiopaque markers to facilitate orientation of the main body and identification of the fenestrations, as well as diameter-reducing ties to allow for intracorporeal maneuvering of the device (Fig. 32.1). This led to the development of the Cook Zenith Fenestrated AAA Endovascular stent-graft (Cook Medical Inc., Bloomington, IN), which was commercially approved in the USA by the Food and Drug Administration (FDA) in 2012 [4]. Advances in the technology have continued, with the addition of preloaded catheters/wires, directional branches, inner branches, upper extremity access, and off-the-shelf devices. Application of this technology has also progressed, from juxtarenal AAA to TAAA, chronic post-dissection aneurysms, and more recently, to aortic arch pathologies [1].

Stent-Graft Designs

It is important to note that some of the stent-grafts discussed in this section are still in clinical trials and are not commercially available.

Cook Zenith Fenestrated Stent-Graft

The Cook Zenith Fenestrated was approved by the FDA for use in the United States for aneurysms with short infrarenal necks, measuring >4 and < 15 mm. The components of the device include a proximal fenestrated main body, with a universal bifurcated distal device and contralateral limb extension. The device is constructed of woven polyester, sewn to self-expandable stainless steel Cook Z-stents. The fenestrated component is patient-specific, custom-made for each patient’s anatomy. Designs may include up to three fenestrations, of which two can be of the same type. Options include small fenestrations (6 × 6 mm or 6 × 8 mm) that are reinforced with nitinol, with no stent struts crossing through the fenestration. Large fenestrations (8–12 mm) are not nitinol-reinforced and may have struts crossing through the fenestration, making placement of alignment stents more difficult. Scallops are openings in the cephalad edge of the graft fabric, which measure 10 mm wide by 6–12 mm high (Fig. 32.2) [4].

Preoperative Planning

The most important aspect of preoperative planning is identification of a healthy proximal and distal sealing zone (Fig. 32.3). Preoperative CT angiography (CTA) should be evaluated with centerline of flow (CLF) imaging. This will provide the greatest amount of information on the extent of disease. Aortic dilatation can be readily identified, compared with adjacent segments, and evaluated for specific vessel involvement. Generally, a minimum of 2 cm of length is preferred for sealing zones, with a segment of parallel aortic walls. Segments with a reverse conic configuration, or those with significant calcium or thrombus, are not suitable necks and should be considered part of the pathology [9].

Supra-celiac sealing zones are preferred whenever feasible. Our practice is to treat pararenal aneurysms with at least three fenestrations and a CA scallop, whereas paravisceral and extent IV TAAAs are typically repaired with four fenestrations. The authors favor a sealing length of 2.5 cm for TAAAs, and if there are no paired intercostal arteries cephalad to this, the sealing zone is extended for 3–4 cm [9].

The method of target vessel incorporation is largely based on anatomy. Fenestrations are selected when the vessels originate from narrower aortic diameters (<30 mm). This is the method most often used for pararenal and extent IV TAAAs. Additionally, fenestrations are preferred for renal artery incorporation if possible, because of their excellent 5-year patency rates. Transversely oriented or up-going vessels—frequently seen in extent I TAAAs—are also well suited for fenestrations. Directional branches are utilized for more extensive aneurysms, in which the inner aortic diameter is >30 mm. They are advantageous particularly for caudally oriented vessels such as the CA and SMA, or when renal arteries are down-going. Directional branches are typically deployed 2 cm cephalad to their intended target, resulting in the need for higher sealing zones.

Repair is usually performed with access via one or both iliofemoral arteries. The CTA should be scrutinized for small-caliber iliac arteries, severe calcification, occlusion, or tortuosity. In these cases, iliofemoral conduits may be required. Upper extremity access is an important adjunct in complex cases that involve directional down-going branches, or when target vessels are caudally oriented. The CA frequently can demonstrate stenosis due to median arcuate ligament compression, and efficient cannulation in these cases is also facilitated by an upper extremity approach. Many operators prefer left-sided upper extremity access to avoid crossing the aortic arch. The authors’ practice has evolved away from selecting the left side whenever feasible, moving to the right side because of evidence of equivalent cerebroembolic complications. In addition, the right arm can be tucked at the patient’s side to simulate femoral access, decreasing operator radiation exposure and improving ergonomics and workflow. Aortic arch anatomy should always be assessed, including arch type and thrombus and calcium burden, as well as disease of the supra-aortic trunks. Type III and some type II arches are better suited for left-sided access to prevent undue strain and manipulation of the arch.