Aortic aneurysm morphology in Asians: Features affecting stent-graft application and design

Purpose: To determine the morphological features of abdominal aortic aneurysms (AAA) in an Asian cohort in order to identify unique features relevant to stent-graft planning and application. Methods: Spiral computed tomography (CT) and angiographic assessment of AAA morphology was performed on 65 ethnic Chinese (58 men; mean age 74 years, range 50-87) who underwent endovascular AAA repair. Morphological parameters were compared with published data from American and European patients. The eligibility and potential concerns referable to 4 current stent-graft designs were addressed. Results: Both common iliac arteries (CIA) measured significantly shorter in Asians, particularly on the right side. The mean RCIA and LCIA lengths were 29.9 mm and 34.2 mm, respectively (25.7 and 34.1 mm for CIAs <20 mm in diameter), compared to >50-mm in Caucasians (p<0.001). The distance between the lowest renal artery and the CIA bifurcation averaged 20 mm shorter in Asians: 148 mm on the right side and 153 mm for the left. The CIAs were also wider, averaging 20.2 mm for the right and 17.9 mm for the left. Other linear measurements did not show a population difference. The AAAs in this series were slightly larger (p<0.001), with a shorter neck (mean 23 mm, p<0.001). No correlation was found between the morphological parameters and body build. Internal iliac artery coverage with or without embolization was necessary in 51% of endovascular repairs due to short or aneurysmal CIAs. Conclusions: These differences in AAA morphology pose unique challenges for endovascular repair in Asians. Preoperative angiography is more often necessary. The need for an accurate landing in a short CIA and insufficient length for maneuvering placed constraints on 2-piece graft designs with long main body lengths. A 3-piece endograft with wider aortic and iliac diameters is currently the most attractive option.