Advanced endografting techniques: snorkels, chimneys, periscopes, fenestrations, and branched endografts

Abstract

The anatomy of aortic aneurysms from the proximal neck to the access vessels may create technical challenges for endovascular repair. Upwards of 30% of patients with abdominal aortic aneurysms (AAA) have unsuitable proximal neck morphology for endovascular repair. Anatomies considered unsuitable for conventional infrarenal stent grafting include short or absent necks, angulated necks, conical necks, or large necks exceeding size availability for current stent grafts. A number of advanced endovascular techniques and devices have been developed to circumvent these challenges, each with unique advantages and disadvantages. These include snorkeling procedures such as chimneys, periscopes, and sandwich techniques; "homemade" or "back-table" fenestrated endografts as well as manufactured, customized fenestrated endografts; and more recently, physician modified branched devices. Furthermore, new devices in the pipeline under investigation, such as "off-the-shelf" fenestrated stent grafts, branched stent grafts, lower profile devices, and novel sealing designs, have the potential of solving many of the aforementioned problems. The treatment of aortic aneurysms continues to evolve, further expanding the population of patients that can be treated with an endovascular approach. As the technology grows so do the number of challenging aortic anatomies that endovascular specialists take on, further pushing the envelope in the arena of aortic repair.

Keywords: Abdominal aortic aneurysm (AAA); branched endograft; endovascular; fenestrated; snorkel.

Figure 1

Eighty-five yo M with a history of a treated infrarenal abdominal aortic aneurysm with a growing sac. Patient underwent successful repair of a type 1a endoleak with Aptus^TM Heli-FX^TM EndoAnchor^TM (Medtronic Inc, Sunnyvale, CA, USA). However, on follow-up imaging patient had continued sac growth. (A,B) Patient underwent proximal extension of the seal zone with simultaneous stenting of the left renal artery using the chimney technique.

Figure 2

Sixty-five yo M with a small infrarenal AAA and large bilateral common iliac artery aneurysms who underwent endovascular repair with hypogastric snorkel technique. (A) Volume rendering of preoperative CT demonstrates bilateral common iliac artery aneurysms and a small infrarenal aneurysm; (B,C) intra-procedure spot images demonstrate endovascular aortic repair using an Endologix AFX^® (Endologix Inc, Irvine, CA, USA) endograft in combination with snorkeling of bilateral hypogastric arteries using Gore^® Viabahn^® stents to preserve hypogastric flow; (D) a 1 month postoperative CT at the level of the bilateral common iliac artery aneurysms demonstrates the parallel orientation of the stent grafts. AAA, abdominal aortic aneurysms.

Figure 3

Seventy yo F with a paravisceral aneurysm that underwent a two stage endovascular repair with a physician modified fenestrated Cook^® Zenith^® Alpha^TM endovascular device. (A) Fluoroscopic image demonstrates successful cannulation of the SMA and right renal artery through the physician created fenestrations. Each fenestration is outlined by a radiopaque marker to allow visualization under fluoroscopy. Of note, the left renal fenestration did not align properly making cannulation of a previously placed left renal iCAST^TM (Atrium Medical, Merrimack, NH, USA) stent not possible; (B) scout film shows Gore^® Viabahn^® stents through the SMA and right renal fenestration creating a branch into their respective target vessels; (C) digital subtraction angiogram of the right renal artery demonstrates adequate flow through the branch. Note the reflux into the aorta demonstrates no significant filling of the left renal artery via the left sided fenestration.

Figure 4

Sixty-five yo M with a thoracoabdominal aortic aneurysm that underwent a two-stage treatment. The infrarenal portion was treated prior to proximal extension with a physician modified branched endograft with a Cook^® Zenith^® TX2^TM main body and Gore^® Viabahn^® branches. A fenestration was cut to supply the left renal artery. (A) Lateral spot view from the procedure shows the physician modified branches for the celiac and superior mesenteric arteries; (B) lateral spot view shows each branch extended with additional Gore^® Viabahn^® stents into their target vessels; (C) an anteroposterior spot view shows placement of a Gore^® Viabahn^® stent through the left renal fenestration and into the left renal artery; (D,E) 3D and maximum intensity projection reformats show the main body and branch stent grafts; (F) picture demonstrating the modified graft as it appeared after its back table modification.

Figure 5

Compilation of available off the shelf branched devices. (A) Cook^® Zenith^® t-Branch^® TAAA Endograft has four branched limbs for stenting of the celiac, SMA, and bilateral renal arteries when treating thoracoabdominal aortic aneurysms. Permission for use granted by Cook Medical, Bloomington, Indiana, USA; (B) Medtronic Valiant^® TAAA Stent Graft system demonstrates its unique, proximal flow divider component with visceral and renal branches. Permission for use granted by Medtronic, Bloomington, Indiana and Sanford Health, Sioux Falls, South Dakota, USA

Figure 6

Graphic and gross images of the Gore^® Excluder^® Iliac Branch Endoprosthesis off the shelf branched device allows preservation of the hypogastric arteries. Permission for use granted by W. L. Gore, Flagstaff, Arizona, USA.