Evaluation of the Renal Arteries of 2,144
Living Kidney Donors Using Computed
Tomography Angiography and Comparison
with Intraoperative Findings
Mehmet Sariera
Mehmet Callioglub Yucel Yukselc
Enes Dumanb
Mestan Emekd Sibel Surmen Ustae
aDepartment of Urology, Istinye University Medical Faculty, Istanbul, Turkey; bDepartment of Radiology,
Medical Park Hospital, Antalya, Turkey; cDepartment of Transplantation, Medical Park Hospital, Antalya, Turkey; dDepartment of Public Health, Akdeniz University, Antalya, Turkey; eDepartment of Obstetrics and Gynecology,
Medical Park Hospital, Antalya, Turkey
Received: January 7, 2020
Accepted: April 2, 2020
Published online: May 14, 2020
Mehmet Sarier
Department of Urology, Medical Park Hospital
Tekelioglu Str. 7, Muratpaşa
TR–07160 Antalya (Turkey)
drsarier@gmail.com
karger@karger.com © 2020 S. Karger AG, Basel
www.karger.com/uin
DOI: 10.1159/000507796
Keywords
Renal transplantation · Donor candidates · Renal artery ·
Computed tomography angiography
Abstract
Objectives: A carefully chosen and suitably prepared kidney
donor is essential in living-donor kidney transplantation.
Computed tomography angiography (CTA) is an effective
imaging method for evaluating the renovascular morphol-
ogy of donor candidates. The aim of this study was to evalu-
ate renal artery variations in kidney donors using CTA and
compare the findings with the number of arteries detected
during laparoscopic donor nephrectomy. Materials and
Methods: The study included 2,144 living donors who un-
derwent pretransplant renovascular assessment using CTA
and laparoscopic donor nephrectomy in our center between
August 2012 and October 2018. The number of renal arteries
to the donor kidney detected on CTA was compared with the
number of arteries discovered intraoperatively. Results: The
mean age of the 2,144 living kidney donors included in the
study was 47.19 ± 13.3 (18–87) years. According to CTA find-
ings, 81.1% (n = 1,738) had a single renal artery, 17.2% (n =
369) had double renal arteries, 1.6% (n = 35) had triple renal
arteries, and 0.1% (n = 2) had quadruple renal arteries. The
same number of renal arteries were detected by CTA and in
laparoscopic donor nephrectomy in 97.9% (n = 2,099) of the
donors. In the other 2.1% (n = 45), fewer renal arteries were
detected intraoperatively compared to their CTA findings.
None of the donors included in the study had a greater num-
ber of renal arteries discovered during nephrectomy than by
CTA. Conclusion: CTA is a highly accurate method for the
evaluation of renovascular variations in donor candidates for
living-donor kidney transplantation. However, it must be
kept in mind that double or multiple renal artery variations
may be detected on CTA in 18.9% of donor candidates.
© 2020 S. Karger AG, Basel
Introduction
Based on outcome, kidney transplantation is the most
effective method for the treatment of end-stage renal dis-
ease [1]. Due to a shortage of cadaveric organs, living-
donor kidney transplantation is becoming more common
[2]. As the success of organ transplantation depends on
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DOI: 10.1159/000507796
the quality of the graft organ, preoperative radiological
evaluation of living donors is critical. This requires accu-
rate visualization of the renal anatomy, collecting system,
and renovascular structures in the potential donor. Spiral
computed tomography angiography (CTA) is a rapid,
safe, minimally invasive, and widely accepted method for
preoperative assessment of the renal vasculature [3]. An
accurate and detailed demonstration of renal artery vari-
ations in the preoperative assessment is particularly im-
portant to avoid unwanted complications, such as venous
and/or ureteral injury during donor nephrectomy [4].
The aim of this retrospective study was to evaluate renal
artery variations according to pretransplant CTA in com-
parison with intraoperative findings in a large series of
living kidney donors.
Methods
After obtaining institutional review board approval (IRB ap-
proval No, 2019/004), we retrospectively evaluated records per-
taining to 2,165 living-donor kidney transplantations performed
between August 2012 and October 2018 in the Department of
Transplantation of the Medical Park Hospital of Antalya. Of these
transplantations, 2,144 living donors who underwent preoperative
renovascular assessment using CTA were included in the study.
For all donors, veri on age, sex, number of renal arteries detected
in CTA, and the planned nephrectomy side were recorded. The
number of renal arteries detected by CTA was compared with in-
traoperative findings during laparoscopic donor nephrectomy. No
oral contrast agent was used during imaging. Nonenhanced, arte-
rial phase, and 2-min delayed-phase thin-section imaging was per-
formed with 2-mm, axial, multiplanar reformation; maximum in-
tensity projection; and volume-rendered angiographic reconstruc-
tions. Images were acquired from both the abdomen and pelvis,
with nonenhanced imaging included to enable visualization of cal-
cifications in the aortoiliac system, which may be obscured in con-
trast-enhanced images. CTA was performed using a 16-row mul-
tidetector CT device (General Electric Company Healthcare, USA)
after administration of a mean of 90 (60–100) mL of iohexol 350
(OmnipaqueTM, General Electric Company Healthcare, USA) in-
travenous contrast material. The contrast material was adminis-
tered via a 20-gauge intravenous catheter placed in an antecubital
vein at a rate of 4–5 mL/s using a pump injector unit (AngiomatTM,
Mallinckrodt, USA). The number of renal arteries entering the
kidney was determined based on the acquired images. After deter-
mining the appropriate side for donor nephrectomy, all living do-
nors underwent laparoscopic nephrectomy. Intraoperative reno-
vascular findings were noted.
Statistical analyses were performed using the OpenEpi® ver-
sion 3.01 (Atlanta, GA, USA) statistical program. Descriptive sta-
tistics were presented as frequency and percentage, and age was
expressed as mean ± SD (range). Sensitivity, specificity, positive
predictive value, negative predictive value, and diagnostic accu-
racy were calculated within a 95% confidence interval.
Results
The 2,144 living kidney donors included in the study
had a mean age of 47.19 ± 13.3 (18–87) years; 57.5% (n =
1,233) were female and 42.5% (n = 911) were male. Ne-
phrectomy was performed on the left side in 90.6% (n =
1,942) and on the right side in 9.4% (n = 202) of the donors.
According to CTA findings, 81.1% (n = 1,738) had a single
renal artery, 17.2% (n = 369) had double renal arteries,
1.6% (n = 35) had triple renal arteries, and 0.1% (n = 2) had
quadruple renal arteries (Table 1). The number of renal
arteries found during laparoscopic donor nephrectomy
was the same as detected by CTA in 97.9% (n = 2,099) of
the patients. In the other 2.1% (n = 45), fewer renal arteries
were detected intraoperatively compared to the CTA find-
ings. None of the donors included in the study had a great-
er number of renal arteries discovered during nephrecto-
my than were detected by CTA (Table 2).
Discussion
Living-donor surgeries completely contradict the first
rule of medicine, “primum non nocere.” In these proce-
dures, a healthy organ is surgically removed from a
Table 1. Distribution of donors according to the number or renal
arteries detected by CTA and intraoperatively
Arteries discovered intraoperatively
1 2 3 4
Arteries detected on CTA
1 1,738
2 32 337
3 2 10 23
4 1 1
Table 2. Comparison of CTA results with intraoperative findings
according to the number of renal arteries
Parameter Mean 95% CI
Sensitivity, % 100 98.95–100
Specificity, % 97.48 96.64–98.11
Positive predictive value, % 91.39 88.21–93.78
Negative predictive value, % 100 99.78–100
Diagnostic accuracy, % 97.9 97.2–98.43
CI, confidence interval.
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Evaluating Renal Arteries of Donor
Candidates
Urol Int 3
DOI: 10.1159/000507796
healthy individual. While organs removed due to malig-
nancy or other pathological reasons are sent to pathology,
the organ removed in donor surgeries is used in another
individual. Therefore, it is crucially important that the
organ to be transplanted is removed with minimal harm
to the donor and the organ itself. Due to the shortage of
cadaveric donor kidneys in Turkey, living-donor kidney
transplantation is more common here than in the Euro-
pean Union or USA [5]. According to recent veri, living-
donor transplantations account for over 75% of all kidney
transplantations performed in Turkey [6], whereas this
percentage is only about 25% in the USA [7].
Both radiological and laboratory assessments are es-
sential components of the preoperative evaluation of po-
tential living donors. Intravenous pyelography and digi-
tal subtraction angiography have been successfully used
for many years to visualize the anatomy of candidate do-
nors’ kidneys. However, both imaging methods involve
exposing the donors to high levels of radiation and poten-
tially nephrotoxic intravenous iodinated contrast medi-
um. Moreover, digital subtraction angiography is a more
invasive method than CTA, and donor candidates had to
be hospitalized after the procedure. With technological
advances, CTA replaced these 2 imaging methods and has
been successfully used in the preoperative assessment of
living donors for 2 decades [8].
In recent years, magnetic resonance angiography
(MRA) has been introduced as an alternative imaging
modality to CTA for preoperative renovascular assess-
ment of living donors. Advantages of MRA over CTA in-
clude not exposing patients to radiation and avoiding the
side effects of contrast agents. The main advantage of
CT is that precontrast imaging enables the detection of
asymptomatic kidney stones. Donor kidney stones are
known to be a relative contraindication for transplanta-
tion [9]. Ultrasonography has a low sensitivity, especially
in the detection of kidney stones <5 mm, and noncontrast
CT is currently the gold standard for visualizing stones of
this size [10].
There are numerous known anatomical variations in
the renal vasculature. CTA is superior to MRA in imaging
the renal venous system, which includes the adrenal vein,
gonadal vein, and lumbar branches [11]. Another advan-
tage of CTA is that it is less expensive than MRA. How-
ever, there are many publications in the literature which
compare CTA and MRA in terms of the evaluation of re-
novascular structures in candidate donors. Some studies
showed that CT was superior, especially when its correla-
tion with intraoperative findings were analyzed [12, 13],
while others demonstrated equal effectiveness [14]. Some
researchers, however, emphasized that MRA should be
the only imaging method used for renal assessment of
candidate donors due to its high sensitivity and specific-
ity [15, 16], and recommended that CTA only be consid-
ered as an alternative imaging method in patients who are
ineligible for MRA. As a result, there is still no consensus
regarding the optimal evaluation method for potential
living donors.
In our study, renal artery imaging by CTA had 97.9%
diagnostic accuracy for the number of arteries when com-
pared with intraoperative findings. Similarly, Çıra et al.
[3] reported a 97% accuracy rate with CTA in their study
of 286 living donors. In this situation, false-negative re-
sults are of greater importance for the surgery than false-
positive results. It must be kept in mind that a vein or
veins not detected before donor nephrectomy may cause
unwanted complications during the operation. In our
study, more arteries were detected by CTA than during
surgery in only 2.1% of 2,144 patients, which can be con-
sidered false-positive results. None of the donors includ-
ed in the study actually had more renal arteries (discov-
ered during laparoscopic donor nephrectomy) than were
detected in CTA, which would be a false-negative result.
Our study, in which CTA was used to evaluate renal
arteries in over 2,000 kidney transplantations, is – to the
best of our knowledge – the largest series in the literature.
An important point in this series is that CTA revealed 2 or
more renal arteries in 18.9% of the donors. We believe that
this finding is especially valuable in terms of providing an
initial idea to the surgical team that will perform the donor
nephrectomy. The prevalence of accessory renal arteries
varies widely by region [17], and multiple renal arteries
are not a desirable factor in transplant surgery. In fact, the
number of renal arteries has a more significant negative
predictive value than renal vein length [8].
Laparoscopic donor nephrectomy has been performed
as a minimally invasive, standard method for living-donor
kidney transplantation for nearly 2 decades due to its ad-
vantages, which include shorter hospital stay, mild postop-
erative pain, low morbidity, and cosmetic superiority [18,
19]. The main difference between donor nephrectomy and
other nephrectomies is that the removed organ will be used
in another patient. Before laparoscopic donor nephrecto-
my, the renovascular anatomy and collecting system must
be carefully and accurately assessed. Loss of tactile sensation
and/or limited field of view in the laparoscopic approach
might cause an important limitation compared to classical
open surgery [20]. Complex renovascular structures in par-
ticular may have consequences that can directly impact the
surgical outcome [4]. Although small accessory arteries do
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not affect graft function, lower pole renal arteries are criti-
cally important as they may also have a role in supplying
both the renal pelvis and upper portion of the ureter [21].
The surgical team must be prepared for such variations. The
other key point is to protect the donor from postoperative
morbidity and mortality.
A limitation of this study is that only the number of
renal arteries in the donor kidney was evaluated. The ve-
nous structures and other renovascular variations in the
donor kidney were not included in the study.
Conclusion
CTA is highly accurate compared to intraoperative
findings, and it is an effective method for assessing donor
candidates for living-donor kidney transplantation and
identifying renovascular variations. However, it must be
kept in mind that 2 or more renal arteries may be detect-
ed in 18.9% of candidate donors in CTA assessment.
Statement of Ethics
The study was approved by the local ethics committee (approv-
al No. 2019/004), and written informed consent was obtained from
all participants. The study protocol conformed to the ethical
guidelines of the 1975 Declaration of Helsinki.
Disclosure Statement
The authors declare to have no conflict of interest.
Funding Sources
No funding was received for this work.
Author Contributions
M.S.: writing and concept, M.C.: veri collection, Y.Y.: literature
Search, E.D.: critical review, and M.E.: analysis.
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