Anatomic variations of the renal arteries, as characterized by computed tomography angiography: rule or exception? Its usefulness in surgical plannning

David C. Shigueoka About the author

In his Traité d'Anatomie Humaine , the classical anatomist Testut noted that "the kidneys, as well as other organs that perform important functions, have an extremely rich and complex vasculature"(11 Sebben GA, Rocha SL, Quidigno EA, et al. Variações das artérias renais: estudo anatômico em cadáveres. Rev Med Res. 2011;13:245-50.). In the previous issue of Radiologia Brasileira, Mello Júnior et al.(22 Mello Júnior C, Araujo Neto SA, Carvalho Junior AM, et al. Multidetector computed tomography angiography of the renal arteries: normal anatomy and its variations. Radiol Bras. 2016;49:190-5.) described the normal appearance of the renal arteries and their most common anatomical variations, as observed with computed tomography (CT) angiography. The authors also discussed the technical aspects of implementing CT angiography, the post-processing of images, and the terminology involved, as well as the clinical and surgical implications.

In a recent study employing CT angiography, Çinar et al.(33 Çinar C, Türkvatan A. Prevalence of renal vascular variations: evaluation with MDCT angiography. Diagn Interv Imaging. 2016. pii: S2211-5684(16)30079-1. [Epub ahead of print].) identified polar renal arteries in 31.3% of the cases and early bifurcation of the hilar artery in 6.5%, which indicates that such anatomic variants are not merely exceptions, but rather are quite common. Therefore, knowledge of these variants is crucial to surgical planning in the treatment of various pathological conditions.

In the current state of the art, CT angiography is superior to magnetic resonance angiography in the evaluation of the renal vessels, as well as other branches of the aorta(44 Araujo Neto SA, Mello Júnior CF, Franca HA, et al. Multidetector computed tomography angiography of the celiac trunk and hepatic arterial system: normal anatomy and main variants. Radiol Bras. 2016;49:49-52.), particularly in the identification of vessels with a diameter of less than 2 mm(55 Arévalo Pérez J, Gragera Torres F, Marín Toribio A, et al. Angio CT assessment of anatomical variants in renal vasculature: its importance in the living donor. Insights Imaging. 2013;4:199-211.), although it may be used in the evaluation of renal arteries with acceptable results(66 Nacif MS, Santos AASMD, Marchiori E. Magnetic resonance angiography in the evaluation of renal arteries: imaging findings. Radiol Bras. 2006;39:253-8.)

Prior to kidney transplantation, the evaluation of a living donor who is a candidate for laparoscopic nephrectomy is one of the main indications for the preoperative study of the renal arteries. The left kidney is most often used because of the technical facility and its longer vascular pedicle, the left renal vein therefore being longer than the right(77 Chu LC, Sheth S, Segev DL, et al. Role of MDCT angiography in selection and presurgical planning of potential renal donors. AJR Am J Roentgenol. 2012;199:1035-41.). In rare cases, anatomic variations of the renal arteries are an absolute contraindication to performing the kidney transplantation, more than three aberrant arteries being considered a limiting factor. Early bifurcation of the renal artery (i.e., the emergence of segmental branches 1.5-2.0 cm from its origin), which was observed in 13% of the patients evaluated in a study conducted by Munnusamy et al., limits the vascular anastomosis in the recipient(88 Munnusamy K, Kasirajan SP, Gurusamy K, et al. Variations in branching pattern of renal artery in kidney donors using CT angiography. J Clin Diagn Res. 2016;10:AC01-3.), and, if necessary, a superior polar artery with a diameter of less than 2 mm can be ligated without significant graft ischemia(99 Sebastià C, Peri L, Salvador R, et al. Multidetector CT of living renal donors: lessons learned from surgeons. Radiographics. 2010;30:1875-90.).

Another important indication for the preoperative study of the renal arteries is the evaluation of candidates for the endovascular treatment of aortic aneurysms, using fenestrated or branched stent grafts. In addition to the location and caliber of the hilar arteries, the presence of polar arteries must be known in order to predict possible kidney injury, although the sacrifice of a small-caliber polar artery that could be obliterated by the prosthesis can be acceptable, provided that the ischemic segment kidney is minimal(1010 Mendes BC, Oderich GS, Reis de Souza L, et al. Implications of renal artery anatomy for endovascular repair using fenestrated, branched, or parallel stent graft techniques. J Vasc Surg. 2016;63:1163-9.e1.).

Mello Júnior et al.(22 Mello Júnior C, Araujo Neto SA, Carvalho Junior AM, et al. Multidetector computed tomography angiography of the renal arteries: normal anatomy and its variations. Radiol Bras. 2016;49:190-5.) also underscored the importance of characterizing any accessory inferior polar artery in the surgical treatment of stenosis at the ureteropelvic junction (UPJ). Although the polar artery is not always the cause of obstruction, its identification is useful in surgical planning, particularly when the procedure will be endoscopic, in which the long longitudinal incision made over the UPJ can injure any vessel in its path, laparoscopic pyeloplasty being an alternative when a polar artery is identified(1111 Liu PS, Platt JF. CT angiography of the renal circulation. Radiol Clin North Am. 2010;48:347-65, viii-ix.). Because UPJ stenosis is typically diagnosed in childhood, magnetic resonance imaging has been used to allow the concurrent assessment of the renal collecting system and of the vascular anatomy, avoiding the disadvantages of using ionizing radiation in this age group, as well as any potential kidney damage caused by the use of iodinated contrast media(1212 Weiss DA, Kadakia S, Kurzweil R, et al. Detection of crossing vessels in pediatric ureteropelvic junction obstruction: clinical patterns and imaging findings. J Pediatr Urol. 2015;11:173.e1-5.).

The terminology used in the description of the anatomical variations is one of the controversial issues in the literature, due to the diversity of terms used. In the literature, anatomic variations of the renal arteries are described variously as extra, additional, supernumerary, aberrant, anomalous, or incidental renal arteries, as well as (superior and inferior) polar arteries arising from the aorta or simply polar arteries. The nomina anatomica in Portuguese is silent on the topic of these structures. Mello Júnior et al.(22 Mello Júnior C, Araujo Neto SA, Carvalho Junior AM, et al. Multidetector computed tomography angiography of the renal arteries: normal anatomy and its variations. Radiol Bras. 2016;49:190-5.) recommended the Portuguese-language terminology proposed by Sampaio et al.(1313 Sampaio FJ, Passos MA. Renal arteries: anatomic study of surgical and radiological practice. Surg Radiol Anat. 1992;14:113-7.) and employed by Palmieri et al.(1414 Palmieri BJ, Petroianu A, Silva LC, et al. Study of arterial pattern of 200 renal pedicle through angiotomography. Rev Col Bras Cir. 2011;38:116-21.), both of whom conducted studies in Brazil and who used (the equivalents of) the denominations hilar artery, (superior and inferior) extra-hilar artery, (superior and inferior) polar artery, and early bifurcation, as well as providing a detailed description of each. It should be borne in mind that the Portuguese-language equivalent of the term accessory polar artery (artéria acessória polar) is also widely used in Brazil. A consensus on the anatomical terminology employed across the different specialties involved would certainly be well received.

Finally, Mello Júnior et al.(22 Mello Júnior C, Araujo Neto SA, Carvalho Junior AM, et al. Multidetector computed tomography angiography of the renal arteries: normal anatomy and its variations. Radiol Bras. 2016;49:190-5.) provided practical recommendations for the interpretation of CT angiography of the renal arteries, guiding the detailed description, plus measures, which promotes greater consistency in communicating the findings to the surgeon, as previously suggested by other authors(1515 Ghonge NP, Gadanayak S, Rajakumari V. MDCT evaluation of potential living renal donor, prior to laparoscopic donor nephrectomy: What the transplant surgeon wants to know? Indian J Radiol Imaging. 2014;24:367-78.).

In conclusion, the radiologist plays an important role in the diagnostic and preoperative evaluation of the renal vasculature, contributing to the reduction of complications, as well as promoting the success, of therapeutic interventions.

REFERENCES

  • 1
    Sebben GA, Rocha SL, Quidigno EA, et al. Variações das artérias renais: estudo anatômico em cadáveres. Rev Med Res. 2011;13:245-50.
  • 2
    Mello Júnior C, Araujo Neto SA, Carvalho Junior AM, et al. Multidetector computed tomography angiography of the renal arteries: normal anatomy and its variations. Radiol Bras. 2016;49:190-5.
  • 3
    Çinar C, Türkvatan A. Prevalence of renal vascular variations: evaluation with MDCT angiography. Diagn Interv Imaging. 2016. pii: S2211-5684(16)30079-1. [Epub ahead of print].
  • 4
    Araujo Neto SA, Mello Júnior CF, Franca HA, et al. Multidetector computed tomography angiography of the celiac trunk and hepatic arterial system: normal anatomy and main variants. Radiol Bras. 2016;49:49-52.
  • 5
    Arévalo Pérez J, Gragera Torres F, Marín Toribio A, et al. Angio CT assessment of anatomical variants in renal vasculature: its importance in the living donor. Insights Imaging. 2013;4:199-211.
  • 6
    Nacif MS, Santos AASMD, Marchiori E. Magnetic resonance angiography in the evaluation of renal arteries: imaging findings. Radiol Bras. 2006;39:253-8.
  • 7
    Chu LC, Sheth S, Segev DL, et al. Role of MDCT angiography in selection and presurgical planning of potential renal donors. AJR Am J Roentgenol. 2012;199:1035-41.
  • 8
    Munnusamy K, Kasirajan SP, Gurusamy K, et al. Variations in branching pattern of renal artery in kidney donors using CT angiography. J Clin Diagn Res. 2016;10:AC01-3.
  • 9
    Sebastià C, Peri L, Salvador R, et al. Multidetector CT of living renal donors: lessons learned from surgeons. Radiographics. 2010;30:1875-90.
  • 10
    Mendes BC, Oderich GS, Reis de Souza L, et al. Implications of renal artery anatomy for endovascular repair using fenestrated, branched, or parallel stent graft techniques. J Vasc Surg. 2016;63:1163-9.e1.
  • 11
    Liu PS, Platt JF. CT angiography of the renal circulation. Radiol Clin North Am. 2010;48:347-65, viii-ix.
  • 12
    Weiss DA, Kadakia S, Kurzweil R, et al. Detection of crossing vessels in pediatric ureteropelvic junction obstruction: clinical patterns and imaging findings. J Pediatr Urol. 2015;11:173.e1-5.
  • 13
    Sampaio FJ, Passos MA. Renal arteries: anatomic study of surgical and radiological practice. Surg Radiol Anat. 1992;14:113-7.
  • 14
    Palmieri BJ, Petroianu A, Silva LC, et al. Study of arterial pattern of 200 renal pedicle through angiotomography. Rev Col Bras Cir. 2011;38:116-21.
  • 15
    Ghonge NP, Gadanayak S, Rajakumari V. MDCT evaluation of potential living renal donor, prior to laparoscopic donor nephrectomy: What the transplant surgeon wants to know? Indian J Radiol Imaging. 2014;24:367-78.

Publication Dates

  • Publication in this collection
    Jul-Aug 2016
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