Anatomic Patterns of Distribution of the Renal Arteries' Origin from the Aorta.

Background: To characterize the variation of the renal arteries' origin from the aorta, through examination of computed tomography angiographies (CTAs) in a cohort of patients, and to evaluate any gender-related difference.

Methods: CTA of the thoracoabdominal district in patients with a nondilated aorta (group A), patients with aortic aneurysm involving the origin of splanchnic and/or renal vessels (group B), and patients with abdominal aortic aneurysm (group C), were retrospectively analyzed. The diameter and angles of emergence (axial and craniocaudal) of the renal arteries were measured, as well as their mutual distance, and the distance between the renal vessels and the superior mesenteric artery/the aortic bifurcation. Shapiro-Wilk, one-way analysis of variance and bivariate Pearson's Correlation tests were performed as appropriate. A P value <0.05 was considered statistically significant.

Results: Six-hundred CTA of patients (452 males) were examined, being 286 in group A, 119 in group B, and 195 in group C. When examining the whole population and also the subgroup of female patients, the clock position of the right renal artery (RRA) was the only parameter that followed a Gaussian distribution, and its ostium raised from the aorta with a mean axial angle of -61.5° ± 16.6°. There was a negative correlation between left renal artery (LRA) and RRA's coronal angle and aortic diameter at the same level, as well as between the LRA's clock position and the aortic diameter at the same level. The longitudinal distances between established landmarks and both renal arteries positively correlated to the aortic diameter.

Conclusions: The LRA showed a high anatomic variability, both in males and in females. With the increase of the aortic diameters in the juxtarenal/infrarenal portion of the aorta, the renal vessels tended to have a more horizontal course in the coronal view, a more acute "clock-position" and longer longitudinal distances between their ostia and the aortic bifurcation.