Morphological Characterization of the Renal Arteries in the Pig: Comparative Analysis with the Human

Abstract

SUMMARY:In spite of its importance as an experimental model, information on the renal artery in pigs is scarce. The objective of this work was to determine the morphological characteristics of the renal artery (RA) and its branches in pigs. One hundred and twenty one (121) pairs of kidneys of pigs destined to slaughter by stunning were studied. The RA and its branches were perfused with polyester resin (Palatal 85 % t Styrene 15 %) and subjected to KOH infusion (potassium hydroxide) for total corrosion. Calibers were measured, and trajectories and relations with adjacent arterial structures were evaluated. Continuous variables were assessed with Student's t test, and discrete variables with Pearson's chi square test. The significance level used was p<0.05. The origin of the RA was symmetric in 57 specimens (50.4 %), with the right renal artery being more cranial in 55 % of the cases. Single renal arteries were seen in 98.4 %, without significant side differences (p=0.31). The caliber and length of the RA were 5.11 mm (SD 1.35) and 30.1 mm (SD 8.63), respectively. A pattern of RA expression that causes one cranial and one caudal polar branch (Type I) was observed in 97.1 % of the cases. The distribution of the RA in cranial and caudal polar branches was found to be higher than what is described in the literature, since these morphometric features have not been reported in prior studies. These findings contribute to a better knowledge in the field of the compared anatomy of the kidney, and allow for applying the pig model in procedural and hemodynamic applications.

Image-guided study of swine anatomy as a tool for urologic surgery research and training

“… 16 in the following types: pattern Ia, with the division of the renal artery into cranial and caudal polar branches, which branch into anterior and posterior segmental branches; pattern Ib, resembles Ia, but has a short cranial polar branch, with the emission of segmental branches directly from the renal artery; pattern II, similar to Ib, but the caudal polar branch gives a branch that irrigates the cranial pole; in pattern III there are multiple renal arteries. The most frequent pattern, as in this study, is the Ia, detected in 77–97% 4 , 16 .…”

“…The results showed that, as in humans, swine renal vascularization is provided by a single renal artery 4 . Although anatomical variations may occur from 30 to 40% in humans, being the accessory polar renal artery the most frequently observed 30 , such variations are rarely observed in pigs (1.7%) 4 and were not detected in this study.…”

“…In pigs, the numbering of the vertebrae may vary, as different breeds may differ in the number of vertebrae 35 . The asymmetry in the level of origin of these arteries is described in pigs and humans 4 , 5 . In this study, only one animal presented such asymmetry, being the origin of the right renal artery 8.5 mm caudal to the left renal artery.…”

“…The renal artery diameter in adult humans varies between 4.0 and 5.9 mm and between 5.1 and 5.4 mm in pigs 4 , 25 , 34 , 36 . In pigs, this data was collected using surgical dissection, plastination and angiography in animals of different breeds between 51 and90 kg 4 , 25 . In contrast to the literature, the present study showed a mean diameter of 4.45 mm on the right and 5.31 mm on the left, being the left renal artery diameter statistically larger than the right renal artery.…”

“…The literature presents anatomical descriptions of the swine urinary system, addressing the pyelocaliceal system 7 , 13 , extra and intrarenal vascularization 4 , 5 , the ureters 14 and the urethra 15 , as well as studies of comparative anatomy. Most of these descriptions were based on surgical dissection, plastination and invasive exams, such as angiography, with a few studies using more modern noninvasive imaging methods, like multislice computed tomography (CT).…”