Abstract
Use of last generation stent-grafts in the endovascular repair of aortic aneurysms is associated with promising clinical results. The design of the endografts aims to expand their applicability in challenging anatomies. This includes the placement of low-profile flexible devices which are beneficial in case of severe iliac calcification and stenosis, kinking of the neck and thrombus formation in the renal arteries. The present chapter demonstrates step by step the standard endovascular approach with additional tips to overcome anatomical obstacles which can influence the results.
Since the first publication of endovascular aneurysm repair (EVAR) by Volodos et al. and Parodi et al., a remarkable evolution in device design, components, and delivery systems has ushered in the applicability of EVAR to challenging anatomies. The main goals remain the optimization of the apposition of the proximal stent-graft to the aortic wall and the improvement of the system’s ability to track through hostile iliac anatomies, as occurs in cases of severe calcification and angulation.
Procedural Steps
The Endurant stent-graft system (Medtronic, Santa Rosa, California, USA) was designed to overcome anatomic limitations, expanding the EVAR population suitable for endovascular repair. The Endurant device is the primary abdominal endograft for infrarenal abdominal aortic aneurysms (AAAs) in Münster, Germany, centers. The short, proximal M-shaped stents, the absence of a longitudinal bar, and the hydrophilic coating of the delivery system represent notable features of this latest-generation endograft. The device received Conformité Européenne (CE) mark approval in July 2008.
The EVAR procedure consists of five steps:
- 1.
After bilateral puncture of the common femoral artery, 8-French (8F) sheaths are inserted in each groin with the Seldinger technique; 5000 units of heparin is administered. In addition, bilateral femoral placement of the Prostar system allows percutaneous access and closure (see Chapter 1 ).
- 2.
The Terumo wire is inserted in the descending aorta and a pigtail catheter advanced over the aortic arch and into the ascending aorta. This is followed by insertion of the Lunderquist double-curved stiff wire into the ascending aorta. The contralateral side will be used for angiography, and therefore a pigtail catheter will be placed at the origin of the renal arteries for administration of contrast.
- 3.
The bifurcated endograft is evaluated, especially the position of the contralateral limb extracorporeally by fluoroscopy. The main body will be advanced over the Lunderquist wire at the level of the renal arteries. After repeated angiographic scans to identify the exact origin of the lowest renal artery, the endograft is deployed. It is important to minimize the parallax effect of the endograft markers by craniocaudal movement of the C-arm.
- 4.
The pigtail catheter is removed and the contralateral limb cannulated with a stiff Terumo wire. Alternative catheters for a successful cannulation of the contralateral limb include the Headhunter Shepherd Hook. The next step is testing of the correct position of the pigtail catheter in the endovascular limb of the endoprosthesis. After this, the contralateral limb will be deployed exactly at the iliac bifurcation, preserving the flow to the hypogastric artery.
- 5.
Lastly, the top cap is removed. After deployment of the limb of the bifurcated endograft is completed, a graduated pigtail catheter is advanced and can be helpful to estimate the exact length of the ipsilateral iliac limb. After this step, the iliac limb is deployed just above the iliac bifurcation.
Procedural Issues
Some challenging and technically demanding issues can arise during EVAR. Challenging Access
Fig. 2.1 illustrates an AAA with severe calcification and stenosis of the iliac arteries and the aortic bifurcation. Several treatment options can be used to overcome this challenging access issue. The first step is to improve the conditions to insert the low-profile endograft by “plain old balloon angioplasty” (POBA). In this case the artery can be predilated with a 7- or 8-mm balloon catheter ( Fig. 2.2 ).
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