Clinical Study | Open Access
Shubha Srivastava, Indra Kumar, C. S. Ramesh Babu, K. K. Gupta, O. P. Gupta, "Clinical Insight into the Precaval Right Renal Artery: A Multidetector Row Computed Tomography Angiographic Study", International Scholarly Research Notices, vol. 2013, Article ID 250950, 6 pages, 2013. https://doi.org/10.5402/2013/250950
Clinical Insight into the Precaval Right Renal Artery: A Multidetector Row Computed Tomography Angiographic Study
Variations of course and number of renal vessels are not so uncommon and their knowledge is important for planning of minimally invasive renal surgeries. The earlier literature reports a prevalence of precaval right renal artery between 0.8% and 5%. Normally, the right renal artery passes posterior to the inferior vena cava, but it can also be precaval where it passes anterior to inferior vena cava. The multidetector row contrast enhanced computed tomography angiography allows precise evaluation of renal vasculature. The aim of this retrospective study is to determine the prevalence of precaval right renal artery. Amongst 73 MDCT scans studied, we identified 4 cases of precaval right renal artery with the prevalence being 5.48%, more than what is reported in the earlier literature. We also report a single and dominant precaval right renal artery in one of the cases, which is a rare finding. On the basis of these results, we conclude that precaval right renal artery appears to be more common and so the knowledge of this variant holds a major clinical implication in preventing misinterpretation of radiological images and proper planning of interventional procedures and minimally invasive surgeries.
A sound knowledge of variations of blood vessels is important during operative, diagnostic, and endovascular procedures in the abdomen. Precaval right renal artery (RRA), although rare, is an important variant of renal vascular anatomy and so identifying this anomaly is important for the planning of minimally invasive renal surgery . The knowledge of the renal vascular variations is of extreme importance for the surgeons who approach the kidneys from the retroperitoneal route or laparoscopically for renal transplants . The renal artery variations also show ethnic and racial differences . The occurrence of these variations holds importance because of the gradual increase of interventional radiological procedures, urological vascular, and transplantation surgeries .
Normally, the right kidney is supplied by the right renal artery passing posterior to inferior vena cava. A Precaval right renal artery (RRA) is defined as a tubular structure with attenuations similar to that of and arising from the aorta or iliac artery that passes anterior to the inferior vena cava (IVC) and terminates in the right kidney . When multiple arteries supply a kidney, the artery with the largest diameter that extends to a given kidney is defined as the dominant renal artery and all other renal arteries are considered as accessory. The present study takes an insight into the prevalence of this anatomical variation and thereby brings awareness to its clinical implications.
2. Materials and Methods
The present retrospective study was done at a single centre in Meerut. No written informed consent was required. The study group consisted of 73 contrast enhanced multidetector row computed tomography (MDCT) angiography scans performed for evaluation of malignancies, abdominal pain, haematuria, or urinary collecting system obstructions. Abdominal aortic dissection, prior urological and renal vascular surgeries, or poorly enhanced scans were not included in the study.
3. CT Technique
All 73 patients in the retrospective study underwent MDCT angiographic evaluation (GE optima 660, 64 channels) and received 90–100 mL of nonionic contrast (omnipaque) at the rate of 5 mL/sec intravenously. Scans were obtained from diaphragm to pubic symphysis and 0.625 mm thick sections were obtained. The scans were analyzed in a workstation (AW volume share 4.5). Volume rendered (VR) and maximum intensity projections (MIP) of axial and coronal scans were studied specifically for the presence of precaval RRA. Presence of other renal vascular anomalies, though noted, was not included in the study.
In this retrospective study, out of the total 73 randomly selected MDCT scans, only 4 patients had precaval right renal arteries giving a prevalence of 5.48%. Of these 4 patients, 2 were men and 2 were women. All precaval RRAs had origin from the aorta and in no case did the branches of the same renal artery passed both anterior and posterior to IVC. A total of 5 precaval right renal arteries were observed in 4 cases, three of them accessory and two dominant.
Case 1. A 29-year-old male has 2 precaval right renal arteries with one dominant and one accessory and a superior polar artery, all arising from abdominal aorta. Left kidney is supplied by a single artery (Figures 1(a), 1(b), 1(c), and 1(d)).
Case 2. A 38-year-old male has one accessory precaval right renal artery entering the lower pole and an accessory and a dominant artery entering the hilum. Left kidney is supplied by a single artery (Figures 2(a) and 2(b)).
During embryonic development, the renal arteries arise from reduction of a series of lateral splanchnic arteries stemming from the aorta supplying blood to the mesonephric kidney. During migration of kidneys from pelvis to lumbar region, kidneys are vascularized by those successive arteries and the final position of the kidney determines the position and number of renal arteries [12, 13]. A precaval RRA is likely to result from a persistent caudal vessel, arising ventrally from the aorta after formation of the inferior vena cava, but before the descent of the gonad .
Many studies have shown that volume rendering (VR), maximum intensity projection (MIP), and multiplanar reformation (MPR) can accurately demonstrate accessory renal arteries. Rubin et al.  showed that the 3D CT angiography is 100% sensitive in the visualization of accessory renal arteries.
Out of the 73 CT scans reviewed in the present study, 4 showed the presence of precaval RRA with a prevalence of 5.48% which is much higher than that reported by Petit et al. , according to whom the prevalence was 0.8% in a series of 380 cases evaluated by ultrasonography (USG) and/or contrast enhanced CT. Yeh et al.  with the help of spiral CT described a prevalence of 5% in 186 cases and suggested that most of the precaval RRAs were accessory lower pole arteries. This coincides with our study where we found precaval accessory RRAs in 3 out of 4 cases (Figures 1, 2, and 3). Meng et al.  identified three cases of precaval right renal arteries, all accessory lower polar arteries during laparoscopic and endourological procedures, the prevalence being 0.6%. Chai et al.  reported one case of precaval RRA in 153 live donors making a prevalence of 0.6%. Bouali et al.  retrospectively reviewed 120 arterial phase, contrast enhanced CT scans focusing specifically on the prevalence of precaval right renal artery and reported an incidence of 9.17%. In majority of their cases, lower pole accessory artery was precaval while the main right renal artery was retrocaval. Only in one case they found both main and accessory right renal arteries in precaval position. There was no case of single and main precaval right renal artery or upper pole precaval artery and there are very few cases of these variants in the literature . A study done on 65 Thai renal donors by CT angiography found an incidence of 4.6% . Gupta et al.  reported a prevalence of 6% precaval right renal arteries in a study of 50 cadavers which is very close to the incidence observed by us. They also observed the presence of a single and dominant precaval RRA . Single main RRA in a precaval position was observed by Holden et al.  in one case out of 100 live donors (1% prevalence) evaluated by MDCT. The findings and the prevalence of precaval RRAs reported in the literature are summarized in Table 1.
An incidental finding of the precaval single main RRA was observed in a contrast enhanced CT of a patient , while three RRAs in precaval position were noted intraoperatively . Babu and Gupta  also reported a case where the right kidney received two hilar additional renal arteries and both showed a precaval course. Radolinski et al.  described a case of a single right renal artery passing anterior to IVC. A cadaveric case report with two precaval RRAs was observed by Raheem et al. . In another case report, Gupta et al.  described the occurrence of double precaval right renal arteries in a male cadaver, one main and one accessory, entering the hilum with the accessory artery crossing in front of ureteropelvic junction. Wadhwa and Soni  in a cadaveric dissection showed the presence of double precaval right renal arteries entering the hilum. Four precaval right renal arteries of aortic origin with the association of double ureter have also been described in a cadaver .
It has been suggested that accessory renal arteries to the lower pole of either kidney that cross the ureteropelvic junction (UPJ) can contribute to obstruction of UPJ. Accessory lower pole right renal artery crossing in front of inferior vena cava and causing obstruction of UPJ has been reported by some authors [5, 22, 23].
The actual incidence of precaval right renal arteries may be higher than that reported in the literature because many such cases might have been missed by an unaware radiologist. It is also possible that the CT technique may have missed other very small accessory renal arteries less than 1-2 mm in diameter . Krishnaveni and Kulkarni  reported the presence of five right renal arteries in an ectopic kidney and other vascular anomalies in a single cadaver and all five right renal arteries were in a precaval position, but the authors failed to notice this anomaly and hence did not comment on it. Since renal vascular anomalies are commonly encountered, thorough knowledge of the variations will enhance the proper interpretation of radiological images and performance of safer surgical interventions.
Knowledge of renal vascular variations has major implication in the clinical practice and it contributes to safety of renal and retroperitoneal surgeries. The present study reported a higher prevalence of precaval right renal arteries (5.48%) than described in the earlier literature. We also report a single and dominant precaval RRA in one case. The occurrence and knowledge of precaval RRAs hold importance as they may be one of the causes for UPJ obstruction and they may be injured during endopyelotomy or may be confused with other vessels such as mesenteric or gonadal at laparoscopy.
Conflict of Interests
The authors declare that they have no conflict of interests.
The authors gratefully acknowledge thetechnical assistance rendered by Mr. Arjun Singh, Radiology Technician, and Mr. Tithender, Photographer, in preparation of the scans.
- H. S. Lee, H. C. Kim, H. C. Shin et al., “Incidental finding of a precaval right renal artery on CT: a case report,” Journal of Korean Radiology Society, vol. 52, no. 5, pp. 351–353, 2005.
- R. M. P. Fernandes, F. H. P. Conte, L. A. Favorito, M. Abidu-Figueiredo, and M. A. Babinski, “Triple right renal vein: an uncommon variation,” International Journal of Morphology, vol. 23, no. 3, pp. 231–233, 2005.
- E. Boijsen, “Renal angiography: techniques and hazards, anatomic and physiologic considerations,” in Abrams’ Angiography, S. Baum, Ed., pp. 1101–1131, Little Brown and Company, Philadelphia, Pa, USA, 4th edition, 1997.
- K. Khamanarong, P. Prachaney, A. Utraravichien, T. Tong-Un, and K. Sripaoraya, “Anatomy of renal arterial supply,” Clinical Anatomy, vol. 17, no. 4, pp. 334–336, 2004.
- B. M. Yeh, F. V. Coakley, M. V. Meng, R. S. Breiman, and M. L. Stoller, “Precaval right renal arteries: prevalence and morphologic associations at spiral CT,” Radiology, vol. 230, no. 2, pp. 429–433, 2004.
- P. Petit, C. Chagnaud, P. Champsaur, and F. Faure, “Precaval right renal artery: have you seen this?” The American Journal of Roentgenology, vol. 169, no. 1, pp. 317–331, 1997.
- M. V. Meng, B. M. Yeh, R. S. Breiman, B. F. Schwartz, F. V. Coakley, and M. L. Stoller, “Precaval right renal artery: description and embryologic origin,” Urology, vol. 60, no. 3, pp. 402–405, 2002.
- J. W. Chai, W. Lee, H. Y. Yong et al., “CT angiography for living kidney donors: accuracy, cause of misinterpretation and prevalence of variation,” Korean Journal of Radiology, vol. 9, no. 4, pp. 333–339, 2008.
- A. Holden, A. Smith, P. Dukes, H. Pilmore, and M. Yasutomi, “Assessment of 100 live potential renal donors for laparoscopic nephrectomy with multi-detector row helical CT,” Radiology, vol. 237, no. 3, pp. 973–980, 2005.
- A. Gupta, R. Gupta, and R. Singhal, “Precaval right renal artery: a cadaveric study. Incidence and clinical implications,” International Journal of Biological and Medical Researchs, vol. 2, no. 4, pp. 1195–1197, 2011.
- P. Apisarntharanak, V. Suvannarerg, K. Muangsomboon, T. Taweemonkongsap, and N. S. Hargrove, “Renal vascular variants in living related renal donors: evaluation with CT angiography,” Journal of the Medical Association of Thailand, vol. 95, no. 7, pp. 941–948, 2012.
- O. Bouali, D. Labarre, F. Molinier et al., “Anatomical variation of the renal vessels: focus on the precaval right renal artery,” Surgical and Radiologic Anatomy, vol. 34, pp. 441–446, 2012.
- S. W. Gray and J. E. Skandalakis, “The kidney and ureter,” in Embryology For Surgeons: the Embryological Basis for the Treatment of Congenital Defects, pp. 443–518, WB Saunders Company, Philadelphia, Pa, USA, 1972.
- G. D. Rubin, E. J. Alfrey, M. D. Dake et al., “Assessment of living renal donors with spiral CT,” Radiology, vol. 195, no. 2, pp. 457–462, 1995.
- G. Tulunay, I. Ureyen, A. Karalok, T. Turan, and N. Boran, “A ptotic kidney with multiple arteries, one from a common renal artery stem,” Asian Pacific Journal of Reproduction, vol. 1, no. 4, pp. 318–319, 2012.
- C. S. R. Babu and O. P. Gupta, “MDCT angiographic evaluation of multiple renal arteries: a case report,” International Journal of Anatomical Variations, vol. 5, pp. 1000–1003, 2012.
- B. Radolinski, E. K. Diner, and S. R. Ghasemian, “Precaval right renal artery during laparoscopic donor nephrectomy,” Transplantation, vol. 82, no. 11, pp. 1554–1555, 2006.
- O. Raheem, P. Glacken, M. O'Brien, D. Hickey, and P. Mohan, “A single male cadaver with multiple renal arteries,” Irish Journal of Medical Science, vol. 177, no. 3, pp. 265–267, 2008.
- A. Gupta, P. Kumar, G. Soni, and L. Shukla, “Double precaval right renal artery associated with multiple left renal arteries: a rare case report,” International Journal of Anatomical Variations, vol. 4, pp. 137–138, 2011.
- A. Wadhwa and S. Soni, “Double precaval right renal arteries: its clinical implications,” International Journal of Medical and Health Science, vol. 1, no. 4, pp. 76–79, 2012.
- S. Madhyastha, R. Suresh, and R. Rao, “Multiple variations of renal vessels and ureter,” Indian Journal of Urology, vol. 17, pp. 164–165, 2001.
- S. Corey, R. Bechtold, and R. Dyer, “Radiological case of the month,” Applied Radiology, vol. 34, no. 2, pp. 33–37, 2005.
- I. Y. Yun, S. Lee, K. P. Kang et al., “A case of hydronephrosis caused by a precaval right lower polar artery,” Clinical Nephrology, vol. 68, no. 1, pp. 61–63, 2007.
- J. F. Platt, J. H. Ellis, M. Korobkin, and K. Reige, “Helical CT evaluation of potential kidney donors: findings in 154 subjects,” The American Journal of Roentgenology, vol. 169, no. 5, pp. 1325–1330, 1997.
- C. Krishnaveni and R. Kulkarni, “A right ectopic kidney with bilateral multiple anomalies of the renal vasculature: a case report,” Journal of Clinical and Diagnostic Research, vol. 7, no. 1, pp. 150–153, 2013.
Copyright © 2013 Shubha Srivastava et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.