The Chimney and Periscope Graft Technique: Emergent Endovascular Solutions for Rupture of the Visceral Abdominal Aorta

Papazoglou and colleagues ¹ reported in this issue of JEVT their version of a Greek bailout solution: successful repair of spontaneous rupture of the abdominal aorta with the periscope graft technique. Because the periscope technique was not initially planned, the authors used this procedure as a bailout maneuver to treat a type lb endoleak, along with stenting of an unintentionally covered celiac trunk. The article opens a new horizon in the emergent treatment of rupture of the visceral aorta.

Endovascular repair of the infrarenal aorta has developed into a less invasive treatment, with good results compared to open surgery.^2–4 With currently available endografts, this is, however, effective only if several anatomical characteristics fulfill strict criteria. To further expand the applicability of the less invasive endovascular approach to patients with challenging anatomy, fenestrated or branched endografts have been used. However, these devices are custom-made, which frequently requires over six weeks, so they cannot be used in emergent situations. Additionally, these procedures are relatively complex and are performed only in a limited number of institutions.

An alternative that can be used is the “chimney graft” technique, ⁵ which has also been described as the “double barrel” ⁶ or “snorkel” ⁷ technique. A variation is the “terrace configuration” ⁸ or “sandwich graft” ⁹ technique, which consists of deploying one or more chimney stent-grafts between main body stent components. Another variant is the “periscope graft” technique, ¹ which has also been known as the “reversed chimney.” ¹⁰ In the “periscope graft” technique, the side branch stent-graft is not directed proximally but caudally. All these different procedures involve placement of adjunctive stents in the side branches of the aorta alongside the main aortic stent-graft.

There are currently no published data available comparing chimney and periscope graft techniques. Only a limited number of case reports and case series regarding these procedures are available in the literature, including the experience of our team with chimney graft repair for visceral aortic aneurysm rupture. ⁵ In this case, stents were placed in the celiac artery and superior mesenteric artery alongside the endograft. The renal arteries were covered in this patient, who had pre-existing renal failure and was on hemodialysis preoperatively. The patient required another chimney procedure 2 weeks after the initial one to treat a type la endoleak. Subsequent computed tomographic angiography at 1 and 6 months confirmed a good result, with no endoleaks or graft migration.

A recent meta-analysis of published reports on the chimney graft technique for aortic pathology involving the visceral vessels by Moulakakis et al. ¹¹ provided more insight into the current global experience with this procedure. They described implantation of 134 chimney grafts in 93 patients, of which 8 were periscope grafts. Perioperative mortality was 4.3%. Patency of the chimney grafts was 97.8% after a mean follow-up of 9 months. Type la endoleaks, which have been considered the “Achilles' heel” of this technique by some authors, occurred in 14%. The majority of these endoleaks sealed spontaneously, however, within the first postoperative month and did not require a reintervention.

It seems counterintuitive that the cylindrical chimney grafts and aortic stent-grafts can create a good proximal seal and control the flow into the stent-graft lumens and not into the “gutters” between the stent-grafts and the aorta. However, the previously described meta-analysis and a recently published retrospective cohort study by Lee et al. ⁸ reported a surprising lack of type la endoleaks. Hypothetical explanations for this observed phenomenon are the interaction between blood and graft, the low flow of the outer layer of blood, clot formation, low outflow within the aneurysm sac, and conformability and deformation of the native aorta. Technical factors that have been suggested to further improve proximal sealing include increased oversizing, minimizing the number of chimney grafts, and increased length of coverage of the proximal landing zone.^5,11,12

The chimney and periscope graft techniques provide a viable alternative for emergency patients unfit for open repair and have the advantage of using stents that are already available in most institutions. Considering the anatomical challenges of the visceral aorta, the chimney and periscope graft technique can provide emergent endovascular solutions for rupture of the visceral abdominal aorta and may serve as bailout solutions for unintentionally covered visceral side branches. Long-term data are needed to provide more information regarding safety and durability.