Introduction

TThe renal arteries are the principal blood supply to the kidneys, arising from the abdominal aorta and branching into segmental arteries that perfuse renal parenchyma. While the classical description includes a single renal artery supplying each kidney, numerous anatomical variations are well documented. These variations hold immense clinical significance, particularly in renal transplantation, vascular surgery, urology, and interventional radiology. A comprehensive understanding of renal arterial anatomy is crucial to prevent iatrogenic injuries, ensure adequate renal perfusion, and optimize surgical outcomes. One of the most common variations is the presence of accessory or supernumerary renal arteries. These are additional vessels that may arise from the aorta, iliac arteries, or other nearby sources. Accessory arteries often supply the renal poles, particularly the inferior pole, and are end arteries without collateral circulation. Injury or ligation of these vessels during surgery can result in ischemia and segmental infarction of renal tissue, underscoring their surgical importance [1].

Description

Another frequent variation involves early branching of the renal artery. Normally, the renal artery divides into segmental branches near the renal hilum. However, in some individuals, branching occurs much earlier, even close to the aortic origin. This anatomical configuration complicates vascular anastomosis in renal transplantation and increases the risk of inadvertent injury during laparoscopic nephrectomy or endovascular procedures. Variations in the origin of the renal arteries are also noteworthy. While most renal arteries arise between the first and second lumbar vertebrae, aberrant origins may occur higher (from the thoracic aorta) or lower (from the iliac arteries). Such variations may be encountered during aortic aneurysm repair or angiographic studies, where unexpected vascular anatomy can affect surgical access and stent placement. The diameter and length of renal arteries also show individual variability. Short renal arteries are commonly associated with high renal mobility and may complicate donor nephrectomy, as limited vessel length poses challenges for anastomosis [2].

Polar arteries, which specifically supply the superior or inferior renal poles, represent another clinically significant variant. Inferior polar arteries often cross anterior to the ureteropelvic junction, potentially causing obstruction and hydronephrosis. In such cases, surgical correction of UPJ obstruction requires careful preservation or revascularization of the crossing vessel to prevent renal ischemia. Renal artery variations are also important in endovascular interventions. Procedures such as angioplasty, stenting, and embolization rely on precise vascular mapping. Failure to recognize accessory or anomalous arteries may lead to incomplete treatment of renal artery stenosis or ineffective embolization of renal tumors. Preoperative imaging with CT angiography or MR angiography is therefore indispensable in identifying vascular variants [3].

In renal transplantation, arterial variations are especially critical. Donor kidneys with multiple renal arteries require meticulous dissection and complex vascular reconstruction to ensure adequate perfusion post-transplantation. Although kidneys with multiple arteries were once considered unsuitable, advances in surgical techniques have made their use feasible, provided that vascular anatomy is thoroughly evaluated preoperatively. Similarly, in partial nephrectomy, preserving renal function depends on precise knowledge of segmental vascular anatomy. Since renal arteries are end arteries, damage to a branch can lead to loss of perfusion in the corresponding renal segment. Understanding variations in segmental arterial distribution thus allows for targeted resections with maximal preservation of healthy renal parenchyma [4].

From an embryological perspective, these variations arise due to the persistence of fetal mesonephric arteries. Normally, redundant vessels regress as the definitive renal arteries establish their origin from the abdominal aorta. Failure of regression or persistence of multiple channels explains the diversity of adult renal arterial patterns observed in clinical practice. With the advent of advanced imaging modalities, especially multidetector computed tomography angiography, non-invasive and accurate preoperative mapping of renal vascular anatomy has become routine [5].

Conclusion

Anatomical variations of the renal arteries are common and carry profound clinical implications across multiple surgical and interventional disciplines. Variants such as accessory arteries, early branching, aberrant origins, and polar arteries influence the success of renal transplantation, partial nephrectomy, endovascular procedures, and urological surgeries. Thorough preoperative imaging and detailed anatomical knowledge are indispensable to minimize complications, preserve renal function, and improve patient outcomes. Recognizing the embryological basis and clinical relevance of these variations ensures that surgeons and clinicians can anticipate challenges and adapt surgical strategies accordingly.

Acknowledgement

None.

Conflict of Interest

None.

References

1. Park D, Southern W, Calvo M, Kushnir M, Solorzano C, et al. (2016). Treatment with dalteparin is associated with a lower risk of bleeding compared to treatment with unfractionated heparin in patients with renal insufficiency. J Gen Intern Med31: 182-187. 

                          Google Scholar   Cross Ref   Indexed at

2. Lazrak HH, René E, Elftouh N, Lafrance JP. (2018). Association between low-molecular-weight heparin and risk of bleeding among hemodialysis patients: A retrospective cohort study. Can J Kidney Health Dis5: 2054358118792010. 

                          Google Scholar   Cross Ref   Indexed at

3. Kaul S, Shah PK. (2000). Low molecular weight heparin in acute coronary syndrome: evidence for superior or equivalent efficacy compared with unfractionated heparin?. J Am Coll Cardiol35: 1699-1712. 

                          Google Scholar   Cross Ref   Indexed at

4. Verhave G, Weijmer MC, Van Jaarsveld BC. (2015). Anticoagulation with dalteparin and nadroparin in nocturnal haemodialysis. Neth J Med73: 270-275. 

                          Google Scholar   Indexed at

5. Wang Q, Xie X, Xu, G. (2020). The risk of bleeding for antiplatelet agents in haemodialysis patients: A meta-analysis. BMC Nephrol21: 106. 

                          Google Scholar   Cross Ref   Indexed at