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A Mayo Clinic study suggests that using kidneys with stones for living donor transplant has little impact on the organ's
ROCHESTER, Minn. -- Results from a Mayo Clinic study
suggest that using kidneys which have kidney stones for
living donor transplant has little impact on the organ's
function one year later.
"This shows that a small kidney stone should not preclude people
from being donors," says George Chow, M.D., Mayo Clinic urologist
and senior investigator of the study. "It's not likely for the
stones to grow if transplanted."
His colleague investigator, Khai-Linh Van Ho, M.D, Mayo Clinic
urology fellow, agrees. "This is good news. We found the stones did
not affect the function of the kidney. As far as we know with 26
months of follow-up, we've had no loss of kidneys from obstruction.
The grafted kidney survival rate was 97 percent -- the same as the
national survival rate for living kidney donation. That's relatively
In the Mayo study, a retrospective chart and radiograph review of
710 donor kidneys, 44 had stones. Of these, 86 percent had 1- to
2-millimeter stones and 14 percent had 3- to 6-millimeter stones. CT
scans performed an average of 10.5 months after transplant surgery
in 14 patients showed no stones in six patients, stable stone size
in four patients and increase in stone size averaging 2.9
millimeters in four patients. No loss of the transplanted kidneys
occurred due to stone obstruction in the patients studied.
The question of how patients fare when transplanted with a kidney
containing stones has arisen due to shortage of available kidneys,
indicate Drs. Chow and Ho. Due to the scarcity, study of
transplantation of more "marginal" kidneys has become relevant, they
"It's a matter of supply," says Dr. Ho. "Demand has so far
outpaced supply of kidneys that we're now considering use of all
kinds of kidneys. We're expanding the criteria with transplant.
Thus, donors with, say, a very small stones or hypertension are now
Helping patients is the reason for investigating transplant of
kidneys that previously would have been considered questionable,
explain Dr. Ho and Dr. Chow. "Our motivation is to save lives and
improve quality of life," Dr. Ho says. "The idea is that patients
would do better off dialysis and mortality rates would decrease.
There would also be fewer burdens on the economy if more patients
were transplanted and off dialysis."
Mortality rates are high for patients on kidney dialysis,
according to the Mayo researchers. They cite a 50 percent mortality
rate within five years of starting dialysis.
Transplantation of a kidney which has stones occurs with full
consent of the donor, recipient and transplant surgeon, and only
after all parties undergo in-depth discussion about the kidney and
any potential risks, says Dr. Ho.
Although risks of transplanting a kidney with stones would
potentially include obstruction from the stone, the Mayo researchers
did not see this issue in the patients they studied. A stone in one
patient grew and he developed urinary tract infections, which were
The investigators recommend that any patients transplanted with a
kidney which has stones should have close follow up with tests
dedicated to kidney stone detection. They also advise that the
patient should be vigilant in looking out for stone obstruction
symptoms like nausea and vomiting; bloody, cloudy or foul-smelling
urine; or a persistent urge to urinate.
The Mayo study was undertaken due to lack of published literature
regarding long-term outcomes with transplanting kidneys which have
One out of 10 Americans develops kidney stones. Ten percent of
those with kidney stones do not have symptoms.
The abstract of the study, No. 1622, entitled "Prevalence and
Early Outcome of Donor Graft Lithiasis in Living Renal Transplants
at the Mayo Clinic," will be presented in a poster session at the
American Urological Association meeting in San Antonio.
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