Introduction:
Analysis of the coexistence of multiple renal arteries and veins is a rare subject in the literature. There are few studies in which the arterial and venous systems of the human kidney are evaluated simultaneously. Aim of the research: The aim of the study was to analyse and correlate variations in the arterial and venous vascularisation of the kidneys in patients diagnosed using computed tomography.

Material and methods:
The study group (1196 patients) included women (592) and men (604), aged from 19 to 92 years, who had imaging scans performed using contrast-enhanced computed tomography. The statistical analysis was performed using Statistica 12.0 software. The relationships were verified with the c2 test. The level of statistical significance was p = 0.05. The mean age of the patients was 58.78 ±15.31 years; the mean age for men was 57.18 ±14.74 years, and for women 60.41 ±15.72 years (p < 0.001).

Results:
As for arterial vascularisation, it was demonstrated that the presence of multiple renal arteries was more common in left kidneys (11.71%) compared with right kidneys (9.95%), whereas multiple renal veins more often occurred in right kidneys (9.03%) than in left kidneys (4.43%). It was generally concluded that there is a correlation between the number of coexisting arteries and veins in the kidneys, which was confirmed statistically (c2 = 55.47; p < 0.001). In the context of anatomic variation regarding the extrarenal arteriovenous system of the kidneys, there is a statistical relationship between the number of coexisting arteries and veins in the kidneys (r = 0.9472; p < 0.001), which has been confirmed by the results of this study.