1Department of Pediatric Nephrology, McMaster University, Hamilton, Ontario, Canada
2Department of Pediatric Nephrology, University of California Davis, Sacramento, CA, USA
*Corresponding author:
Lavjay Butani, MD
Department of Pediatric Nephrology
University of California Davis, 2516 Stockton Blvd
Sacramento, CA 95817, USA Tel:
916-734-8118 Fax: 916-734-0629 E-mail: Lavjay.butani@ucdmc.ucdavis.edu
Received May 23, 2012; Accepted May 23, 2012; Published May 29, 2012
Citation: Lau KK, Butani L (2012) Expanding the Organ Donor Pool: Using En Bloc
Kidneys in Pediatric Recipients. J Nephrol Therapeut 2:e106. doi:10.4172/2161-0959.1000e106
The demand for renal allografts has so far outstripped the available
organ donor pool that the gap between patients awaiting a transplant
and those actually receiving a transplant seems to be forever widening.
Renal transplantation is the ultimate treatment of choice for patients
with end stage renal disease as it offers better long term survival and
quality of life compared to dialysis [1]. Children with end stage renal
disease are especially vulnerable to the organ shortage, since their
psychosocial and neurodevelopmental functioning is adversely affected
by the uremic environment and any delay in transplanting them can
have long term ramifications. Moreover, pre-emptive transplantation
has been shown to improve long term graft survival in children [2] .
These considerations have made it critical for health-care providers to
minimize wait times on dialysis. Among other strategies, expanding
the deceased donor organ pool by using organs from donors previously
thought of as unsuitable, has proven to be a successful strategy.
En Bloc Renal Transplantation is a Viable and Safe
Option to Reduce Wait Times
Retrieval of kidneys from young donors for transplantation,
either as single kidneys or in an ‘en bloc’ manner, allows utilization
of allografts that were previously abandoned and wasted. While the
transplantation of pediatric donor kidneys, especially from donors less
than 5 years old, is still limited to a few specialized centers, the practice
seems to be increasing as evidence of the successes of this strategy
grows [3-7].
Recent reports from various centers have consistently
demonstrated a positive experience using en bloc kidneys in pediatric
and adult recipients. The graft survival of en bloc kidneys has been at
least comparable to standard deceased donor kidneys [4,8-12]. Some
studies in fact have shown superior outcomes with en bloc transplants
compared to standard deceased donor and even live donor transplants
[13-15]. In a recent study from France, researchers compared the
graft survival among recipients of en bloc grafts (mean donor age of
15 months) to those receiving standard donor grafts (mean donor
age of 38 years); those who received en bloc kidneys fared better than
their counterparts, with a 10 year survival of 74% compared to 58%
[14]. The benefits of superior survival of en bloc grafts over the long
haul is especially salient in pediatric patients, as they have a longer
life expectancy and hence have more to gain from maximizing graft
survival [16].
Advantages of En Bloc over Solitary Grafts from Young
or Ideal Donors
Kidneys from small donors have largely been avoided by the
transplant community because of the low nephron mass and a higher
risk of vascular complications. Reduce nephron mass renders the graft
more prone to early hyper-filtration injury; en bloc grafts with twice the
number of nephrons and higher volume may mitigate this risk [17,18].
Based on animal studies and experience from clinical settings, en bloc
grafts but not ideal single kidney donor grafts, increase in size rapidly
to adapt to the host environment [5,15,19-21].
In recipients of pediatric donors kidneys, the absolute Glomerular
Filtration Rate (GFR) rose along with patient growth, and higher GFRs
were sustained when compared to recipients of adult donor kidneys
[22,23]. These observations support the use of young donor kidneys
into pediatric as opposed to adult recipients since pediatric grafts are
better able to acclimatise to the needs of growing children. Although
still somewhat contentious, reports, including one using the United
Network of Organ Sharing (UNOS) database, suggest an advantage of
using of en bloc over single kidneys from young donors [4,24-26].
While early reports of increased vascular complications with en
bloc transplantation were discouraging [27-30], recent reports have
shown more encouraging outcomes [5,11,26,31]. This is likely due to
increased experience and improvements in surgical techniques over
time, which should help further reduce the skepticism in using young
donors for transplantation.
Since follow-up remains relatively limited, many questions still
remain unanswered. Chief among these are the sustained ability of en
bloc kidneys to maintain GFR and the potential risk of hyperfiltration
injury leading to graft loss.
Conclusions
A growing experience from various transplant centers has
demonstrated excellent graft survival of en bloc renal transplants in
both children and adults. En bloc transplantation offers the advantages
of greater nephron mass compared to solitary allografts and rapid
growth in size to match recipient growth. Although this is still a
technically demanding procedure and has been performed mostly
in experienced transplant centers, recent success should increase the
willingness of other centers to follow suit.
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