[Correlation between the stenosis degree of aorto-iliac artery and superior mesenteric artery in patients with lower extremity atherosclerotic occlusive disease by CT angiography].

Objective: To investigate the correlation between the stenosis degree of superior mesenteric artery (SMA) and each artery within the scope of aorto-iliac artery in patients with lower extremity atherosclerotic occlusive disease (LEAOD).

Methods: Images of 70 patients who had undergone the aorta-iliac-femoral arteries CT angiography (CTA) examination and had a definite diagnosis of LEAOD due to intermittent claudication or resting pain admitted to Tianjin Hospital from January to December in 2017 were enrolled. The arteries in the aorta as well as iliac were surface-reconstructed, which were analyzed by advanced vascular analysis (AVA) combined with the original images, including SMA trunk, abdominal aorta (AA), left and right common iliac artery (LCIA, RCIA), left and right internal iliac artery (LIIA, RIIA), left and right external iliac artery (LEIA, REIA). The normal reference plane and the maximal stenosis plane were selected, and the stenosis rate of each artery in the reconstruction range was automatically calculated with software. The patient's imaging data were divided into groups with two methods: (1) according to the degree of SMA stenosis, the patients were divided into group I (stenosis degree ≤70%) and group II (stenosis degree > 70%); (2) LEAOD patients with different gender were respectively divided into three groups: middle-aged group (45-59 years old), pre-elderly group (60-74 years old) and elderly group (75-89 years old). The comparison between the stenosis degree of SMA and each artery within the scope of aorto-iliac artery was analyzed with Pearson simple correlation analysis.

Results: The incidence of SMA stenosis in all LEAOD patients was 100%. Correlation analysis showed that there was no correlation between the stenosis degree of SMA and AA, LCIA, RCIA, LIIA, RIIA, LEIA, or REIA in group I (n = 64) and group II (n = 6), respectively (r value was -0.021, 0.023, 0.023, -0.137, 0.182, -0.113, 0.141, respectively, in group I, and it was 0.020, -0.560, 0.010, 0.306, -0.204, -0.381, 0.393, respectively, in group II, all P > 0.05). In 52 male patients, there was no correlation between the stenosis degree of SMA and AA, LCIA, RCIA, LIIA, RIIA, LEIA, or REIA in middle-aged group (n = 16), pre-elderly group (n = 27) and elderly group (n = 9), respectively (r value was -0.032, 0.024, 0.324, 0.146, 0.312, 0.008, 0.344, respectively, in middle-aged group, it was -0.108, -0.116, -0.040, -0.249, -0.082, -0.052, 0.096, respectively, in pre-elderly group, and it was 0.182, 0.311, 0.400, 0.360, 0.688, 0.498, 0.406, respectively, in elderly group, all P > 0.05). In 18 female patients, there was also no correlation between the stenosis degree of SMA and above each artery within the scope of aorto-iliac artery in pre-elderly group (n = 11) and elderly group (n = 6), respectively (the r value was -0.170, 0.040, -0.019, 0.152, 0.508, 0.042, 0.456, respectively, in pre-elderly group, and it was -0.660, 0.008, -0.055, -0.056, -0.213, 0.344, 0.011, respectively, in elderly group, all P > 0.05). The correlation in middle-aged group was not analyzed because there was only 1 patient.

Conclusions: Although the atherosclerotic changes in LEAOD patients can affect SMA and aorto-iliac artery at the same time, there was no correlation between the stenosis degree of SMA and each artery within the scope of aorto-iliac artery which may due to the differences in the histological structure and hemodynamics among different arteries. SMA atherosclerotic stenosis and occlusion is a relatively independent disease process for LEAOD.