Renal artery entrapment - anatomical risk factors rating.

BACKGROUND Cases of renal artery entrapment (RAE) by extrinsic compression have been infrequently reported in the literature. We aimed to describe RAE and elucidate anatomical factors that may be related to renal artery stenosis. MATERIALS AND METHODS Two hundred and four patients' computed tomography scans made for various reasons in Radiology Department from 2011 to 2015 were retrospectively analysed and 7 cases of RAE were found. Authors studied the level of origin of renal arteries vs. coeliac trunk (CT), superior mesenteric artery (SMA) and vertebrae. Diameter of renal arteries, distance between main left renal artery (LRA) and right renal artery (RRA) as well as renal arterial patterns were also investigated. RESULTS The origin of main renal arteries off the aorta was between the upper margin of L1 and lower margin of L2 vertebra, with the predominant lower 1/3 of L1 vertebra and L1 intervertebral disc. However, in patients with highest range of stenosis of renal artery the origin was most commonly located at the level of Th12 intervertebral disc and upper part of L1. Statistically significant relationships were proven between range of stenosis and level of origin of stenotic renal artery vs. vertebrae (Pearson's correlation coefficient: -0.393, p < 0.01), distance between main LRA and RRA (Pearson's correlation coefficient: 0.398, p < 0.0001), renal artery-CT distance (Pearson's correlation coefficient: -0.263, p < 0.0001), renal artery-SMA distance (Pearson's correlation coefficient: -0.149, p < 0.033). CONCLUSIONS Analysis of RAE allowed finding anatomical factors of renal artery stenosis and classifying them regarding to their importance. Relationship of renal artery origin vs. vertebrae and distance between main LRA and RRA were proven the most important. However, distances between higher originated renal artery and CT, higher originated renal artery and SMA should also be taken into consideration.