Iliac Artery Tortuosity Index in Chinese Patients with or without Aortic Artery Aneurysms and Related Influencing Factors

Iliac artery tortuosity is an important anatomical factor that influences the endovascular repair of aortic artery aneurysms. The influencing factors of the iliac artery tortuosity index (TI) have not been well studied. TI of iliac arteries and related factors in Chinese patients with and without abdominal aortic aneurysm (AAA) were studied in this study.One hundred and ten consecutive patients with AAA and 59 patients without AAA were included. For patients with AAA, the diameter of the AAA was 51.9 ± 13.3 mm (24.7-92.9 mm). Those without AAA had no history of definite arterial diseases and came from a cohort of patients diagnosed with urinary calculi. The central lines of the common iliac artery (CIA) and external iliac artery were depicted. The actual length and the straight distance were measured and used to calculate the TI (actual length/straight distance). Common demographic factors and anatomical parameters were analyzed to identify any related influencing factors.For patients without AAA, the total TI of the left and right side was 1.16 ± 0.14 and 1.16 ± 0.13, respectively (P = 0.48). For patients with AAAs, the total TI in the left and right side was 1.36 ± 0.21 and 1.36 ± 0.19, respectively (P = 0.87). The TI in external iliac artery was more severe than that in CIA both in patients with and without AAAs (P < 0.01). Age was the only demographic factor found to be associated with TI in patients with AAA (Pearson's correlation coefficient r ≈ 0.3, P < 0.01) and without AAA (r ≈ 0.6, P < 0.01). For anatomical parameters, the diameter was positively associated with the total TI (left side: r = 0.41, P < 0.01; right side: r = 0.34, P < 0.01). The ipsilateral CIA diameter was also associated with the TI (left side: r = 0.37, P < 0.01; right side: r = 0.31, P < 0.01). The length of the iliac arteries was not associated with age or AAA diameter. Reduction of the vertical distance of the iliac arteries may be a common underlying reason for age and AAA.Tortuosity of the iliac arteries was probably an age-related problem in normal individuals. It was also positively correlated with the diameter of the AAA and the ipsilateral CIA in patients with AAA. Attention should be paid to the evolution of iliac artery tortuosity and its influence when treating AAAs.