Aortoiliac angulation and the need for secondary procedures to secure stent graft fixation: Which angle is important?

Background. The purpose of this study was to quantify the degree of aortoiliac tortuosity and determine the relationship between aortoiliac angulation and the need for a secondary procedure following endovascular repair. Methods. Among 206 patients treated with the AneuRx stent graft, 3-year follow up data were available in 71 patients. Twenty eight patients without duplex and CT angiograms (CT angiography) on follow-up were excluded. The anatomy of the preoperative proximal aortic neck was evaluated using 3D-CT angiography reconstructed images in: a) Group I: 15 patients who required secondary procedures and b) Group II: 18 patients without any endovascular leak during follow up. The groups did not differ in age (72.9±6.1 versus 73.3±9.1) or aneurysm diameter (60.1±9.1 versus 60.5±10.1). In order to determine the aortoiliac tortuosity, we measured: a) the suprarenal aorta-infrarenal aortic neck angle: angle of the aorta at the level of the renal arteries, b) infrarenal aortic neck-aneurysm angle: angle of the aorta at the start of aneurysm, c) right iliac angle, d) left iliac angle, e) aortic neck length, f) aortic neck diameter. Results. Computer-based measurements on 3D-CT angiography reconstructed images were: a) suprarenal aorta-infrarenal aortic neck angle: group I: (22.6±16.2), group II: (11.9±6.9), p<0.05; b) infrarenal aortic neck-aneurysm angle: group I: 17.6±12.4, group II: 18.8±9.4, p=NS; c) right iliac angle: group I: 22.9±12.6, group II: 20.4±9.5, p=NS; d) left iliac angle: group I: 22.4±10.5, group II: 19.1±12.2, p=NS; e) aortic neck length: group I: 18.9±5.3 mm, group II: 20.4±5.3 mm, p=NS; f) aortic neck diameter: group I: 24.1±1.0 mm, group II: 23.3±1.6, p=NS. Conclusions. Aortoiliac angulation can be defined and quantified. In patients requiring secondary procedures, there is an increased angulation at the proximal aortic neck angle.