Currently there is huge variation in the number patientsreceiving a kidney transplant at the time of their liver transplant across the
US; Combined Liver Kidney Transplant (CLK). The rate of good quality (standard
criteria) kidneys being transplanted at the time of liver transplant varies
from about 20% in the Midwest to about 6% in centers on the east coast, for
example. The reasons for this disparity are varied and there is a real worry
that many Liver transplant patients are receiving a kidney when one is not
really needed. This reduces the number of good kidneys in the kidney alone
pool. In 2012 liver-kidney transplants were the highest of all combined liver
transplantations in the US.
Liver wait list patients are frequently very sick and renal
dysfunction is common in this population of patients. Elevated creatinine can
significantly raise the MELD score placing candidates towards the top of the
liver wait list. There is a survival advantage of CLK vs Liver Transplant alone
(LTA). This puts
pressure on physicians and surgeons to consider transplanting a kidney with the
liver. There may also be financial and statistical reasons for a center to
transplant a kidney with a liver. The outcome data favoring CLK over LTA in
renal failure patients is all retrospective, non-randomized and does not take
into account the cause of peri-transplant renal failure and whether the patient
truly had established ESRD or CKD4 at the time of transplant. Another factor putting pressure on medical
professionals to perform CLK transplants is the fear of ‘getting it wrong’.
Survival is very poor in patients who do not recover renal function after LTA
vs those who do.
Currently a patient put onto the kidney alone list after LTA will have to wait
the average 5 years for their kidney (average kidney alone wait list time in SE
USA). Given the poor outcomes described by Northrup, these patients are likely
to die with a functioning liver waiting for a kidney.
dysfunction is common in this population of patients. Elevated creatinine can
significantly raise the MELD score placing candidates towards the top of the
liver wait list. There is a survival advantage of CLK vs Liver Transplant alone
(LTA). This puts
pressure on physicians and surgeons to consider transplanting a kidney with the
liver. There may also be financial and statistical reasons for a center to
transplant a kidney with a liver. The outcome data favoring CLK over LTA in
renal failure patients is all retrospective, non-randomized and does not take
into account the cause of peri-transplant renal failure and whether the patient
truly had established ESRD or CKD4 at the time of transplant. Another factor putting pressure on medical
professionals to perform CLK transplants is the fear of ‘getting it wrong’.
Survival is very poor in patients who do not recover renal function after LTA
vs those who do.
Currently a patient put onto the kidney alone list after LTA will have to wait
the average 5 years for their kidney (average kidney alone wait list time in SE
USA). Given the poor outcomes described by Northrup, these patients are likely
to die with a functioning liver waiting for a kidney.
So can we predict who who will develop ESRD after LTA? A
number of studies have looked at this using various prediction parameters.
number of studies have looked at this using various prediction parameters.
In summary:
– RRT for less than 30days pre-LTA are likely to recover renal
function
function
– RRT for greater than 90days preLTA are unlikely to recover
– Patients with eGFR consistently less than 30ml/min/1.73m2 (MDRD)
for 90days prior to LTA had an increased risk of ESRD.
for 90days prior to LTA had an increased risk of ESRD.
– ATN vs HRS as a cause of renal failure at time of LTA increases the risk of post LTA CKD 4/5.
So how can we improve the allocation of kidneys in CLK
patients?
patients?
Dr Carl Berg is the Chairman of the OPTN/UNOS policy
oversight committee, incoming UNOS Vice President and a Liver Transplant Physician
at Duke University Medical Center. He recently presented a talk that
highlighted the issues described above. He and others (Richard Formica and
Bertram Kasiske) are working on proposals that will:
oversight committee, incoming UNOS Vice President and a Liver Transplant Physician
at Duke University Medical Center. He recently presented a talk that
highlighted the issues described above. He and others (Richard Formica and
Bertram Kasiske) are working on proposals that will:
– Avoid giving kidneys to liver transplant patients with a
high likelihood of renal recovery
high likelihood of renal recovery
– Provide fail-safe mechanism to provide less penalty for
“guessing wrong” and not putting in a kidney with a liver
“guessing wrong” and not putting in a kidney with a liver
– Create a system that is not easily manipulated.
Some of the proposed ideas are as follows (these are not
official UNOS/OPTN proposals but are proposals based on the expert opinions of
the three mentioned authors CB, RF, BK):
official UNOS/OPTN proposals but are proposals based on the expert opinions of
the three mentioned authors CB, RF, BK):
Fail safe:
1) The patient receives a time credit of the 25th percentile
of waiting time for the center they are listed in.
of waiting time for the center they are listed in.
2) In addition, the patient receives credit for the time
spent from transplant of the primary organ (time of arterial anastomosis to
time of listing).
spent from transplant of the primary organ (time of arterial anastomosis to
time of listing).
This time credit should encourage doctors to allow time for
the kidney to recover but not discourage living donation.
the kidney to recover but not discourage living donation.
Proposed criteria for offering a kidney at the time of Liver
transplant
transplant
•ESRD (as defined by the Form 2728)
•Metabolic disease requiring CLK
•Acute renal failure with ≥8 weeks of dialysis
•CKD with eGFR or CrCl ≤30 mL/min
The duration and time of CKD first documentation needs to be
assessed.
assessed.
This is an interesting and difficult area for the transplant
physician. I certainly agree that clearer guidelines are needed to ensure our
limited pool of good kidneys is used wisely and no ‘game playing’ occurs. With
regard to Dr Berg’s proposals; the AKI and CKD criteria are most troublesome.
We all know kidneys can recover function weeks after an AKI event. Clinical
diagnosis of AKI or even diagnosing CKD in these patients in difficult and
requires great clinical skill from the nephrologist. Performing a kidney biopsy
to gauge likelihood of recovery and cause of AKI sounds attractive but is risky
and costly in this patient group.
physician. I certainly agree that clearer guidelines are needed to ensure our
limited pool of good kidneys is used wisely and no ‘game playing’ occurs. With
regard to Dr Berg’s proposals; the AKI and CKD criteria are most troublesome.
We all know kidneys can recover function weeks after an AKI event. Clinical
diagnosis of AKI or even diagnosing CKD in these patients in difficult and
requires great clinical skill from the nephrologist. Performing a kidney biopsy
to gauge likelihood of recovery and cause of AKI sounds attractive but is risky
and costly in this patient group.
Posted by Andrew Malone
Thanks for sharing your perspective. Very well written and informative.
Memon suggests retrieving renal transplants from patients who recover native renal function after combined liver and kidney transplants. There is a number of problems associated with this. First that comes to my mind would be the difficulty to establish the relative contribution of renal function by the native kidneys vs the transplanted kidney. Second, remember some of these patients have chronic infections, and probably malignancy risk that will be carried with the transplanted kidney. Third: remember that transplant nephrectomy is a surgically difficult procedure. Forth, even if the above problems did not exist, the most important issue would be the ethical problem of having to take this transplant recipient back to the operating room to perform yet another surgical procedure, that carries high risk for renal impairment and potential risks to his/her life. Add to that, that no matter how much recovery there is from the native kidneys, exposure to CNI's and other potential causes of renal impairment make the presence of this already transplanted kidney a potential plus to the survival of the liver transplant recipient.
what about considering recipients who have received CLK, once their GFR improves and suggest their native kidneys are functioning, then donate back their transplant kidney to a potential matched recipient in a controlled environment as a Living donor.