Model May Help Predict Survival After Liver Transplant

[Guest guest]

Model May Help Predict Survival After Liver Transplant

Laurie Barclay, MD

November 3, 2006 — A new model may help predict survival after liver

transplant, according to a report in the November issue of Liver

Transplantation. The model may predict the length of posttransplant survival

when a given donor is offered and may be particularly helpful for marginal

or high-risk donors.

" One way to increase the availability of organs for liver transplantation is

to expand the criteria that are used to determine whether an organ from a

potential liver donor is acceptable for liver transplantation, " write

N. Ioannou, from the the Veterans Affairs Puget Sound Health Care System in

Seattle, Washington, and colleagues.

" Unfortunately, no such universally accepted criteria exist, " according to

Dr. Ioannou. " Instead, individual transplant programs use different, and

often poorly defined, criteria to determine whether to use the liver of a

potential liver donor for transplantation. Such criteria include donor age,

donor high-risk behavior, the degree of steatosis on liver biopsy, cold

ischemia time, down time, and the macroscopic appearance of the liver. "

The objective of this study was to develop and validate a comprehensive

model that predicts survival after liver transplantation, based on

pretransplant donor and recipient characteristics. The United Network for

Organ Sharing had complete data available for 20,301 patients who underwent

liver transplantation in the United States between 1994 and 2003, including

6477 patients infected with hepatitis C virus (HCV). Using

proportional-hazards regression, the investigators identified the donor and

recipient characteristics that best predicted survival and incorporated

these characteristics in a multivariate model.

Exclusion criteria were patients who had donors younger than 10 years or

older than 75 years, living donors, split-liver donors, non–heart beating

donors, donors with serum sodium concentration greater than 170 mmol/L, as

well as patients with multiple organ transplants, previous liver

transplants, and incomplete information.

To best predict survival after liver transplantation in patients without HCV

infection, the model used 4 donor characteristics (age, cold ischemia time,

sex, and race/ethnicity) and 9 recipient characteristics (age, body mass

index, model for end-stage liver disease score, United Network for Organ

Sharing priority status, sex, race/ethnicity, diabetes mellitus, cause of

liver disease, and serum albumin). A slightly different model was used for

patients with HCV infection, including the same donor characteristics, and

all recipient characteristics except cause of liver disease and serum

albumin.

" The models illustrate that variations in both pretransplant donor and

recipient characteristics have a large effect on posttransplant survival, "

the authors write. " The models presented here can be used to derive scores

that are proportional to the excess risk of graft loss after liver

transplantation for potential donors, recipients, or donor/recipient

combinations. The models may be used to inform liver transplant candidates

and their doctors what posttransplant survival would be expected when a

given donor is offered and may be particularly helpful for marginal or

high-risk donors. "

Study limitations include inability to adjust for each individual center;

inability to verify the accuracy of the data; exclusions of persons with

missing data; and the possibility that predictors of survival might have

changed slightly during the 10-year study period.

" Ultimately, risk scores and predicted survivals determined from such models

may be an objective

way to assess the risk of a given liver donor, recipient, or donor/recipient

combination, " the authors conclude. " If two donors are expected to be

available at approximately the same time, it would be more equitable for the

recipient with worse predicted post-transplant survival to receive the donor

with the better predicted survival and vice versa since that would make the

post-transplant survival of the two recipients more similar. "

The American College of Gastroenterology Junior Faculty Development Award,

Veterans Affairs Northwest Hepatitis C Resource Center, Veterans Affairs

Puget Sound Health Care System Research Enhancement Award Program, and the

Health Resources and Services Administration helped fund this study.

In an accompanying editorial, Ignazio R. Marino, MD, FACS, from the

Jefferson University Hospital in Philadelphia, Pennsylvania, recommends a

large prospective study of liver transplant candidates to help optimize

allocation criteria and to define when a prospective donor should not be

used for a prospective recipient.

" If candidates for [liver transplant] can be stratified into different risk

categories at the time of the actual organ allocation, the inevitable

question arises: Should we try to match donors and recipients? " Dr. Marino

writes. " In addition, should we try to implement rules to assess when a

patient is too sick for [liver transplant] and have uniform delisting

criteria?.... We might not be ready to match donors and recipients yet, but

this procedure should be our ultimate goal. "

Liver Transplantation. 2006;12(11):1574-1576, 1594-1606

Laurie Barclay, MD is a freelance reviewer and writer for Medscape.

Medscape Medical News 2006

http://www.medscape.com/viewarticle/547221?src=mp

_________________________________________________________________

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[Guest guest]

Model May Help Predict Survival After Liver Transplant

Laurie Barclay, MD

November 3, 2006 — A new model may help predict survival after liver

transplant, according to a report in the November issue of Liver

Transplantation. The model may predict the length of posttransplant survival

when a given donor is offered and may be particularly helpful for marginal

or high-risk donors.

" One way to increase the availability of organs for liver transplantation is

to expand the criteria that are used to determine whether an organ from a

potential liver donor is acceptable for liver transplantation, " write

N. Ioannou, from the the Veterans Affairs Puget Sound Health Care System in

Seattle, Washington, and colleagues.

" Unfortunately, no such universally accepted criteria exist, " according to

Dr. Ioannou. " Instead, individual transplant programs use different, and

often poorly defined, criteria to determine whether to use the liver of a

potential liver donor for transplantation. Such criteria include donor age,

donor high-risk behavior, the degree of steatosis on liver biopsy, cold

ischemia time, down time, and the macroscopic appearance of the liver. "

The objective of this study was to develop and validate a comprehensive

model that predicts survival after liver transplantation, based on

pretransplant donor and recipient characteristics. The United Network for

Organ Sharing had complete data available for 20,301 patients who underwent

liver transplantation in the United States between 1994 and 2003, including

6477 patients infected with hepatitis C virus (HCV). Using

proportional-hazards regression, the investigators identified the donor and

recipient characteristics that best predicted survival and incorporated

these characteristics in a multivariate model.

Exclusion criteria were patients who had donors younger than 10 years or

older than 75 years, living donors, split-liver donors, non–heart beating

donors, donors with serum sodium concentration greater than 170 mmol/L, as

well as patients with multiple organ transplants, previous liver

transplants, and incomplete information.

To best predict survival after liver transplantation in patients without HCV

infection, the model used 4 donor characteristics (age, cold ischemia time,

sex, and race/ethnicity) and 9 recipient characteristics (age, body mass

index, model for end-stage liver disease score, United Network for Organ

Sharing priority status, sex, race/ethnicity, diabetes mellitus, cause of

liver disease, and serum albumin). A slightly different model was used for

patients with HCV infection, including the same donor characteristics, and

all recipient characteristics except cause of liver disease and serum

albumin.

" The models illustrate that variations in both pretransplant donor and

recipient characteristics have a large effect on posttransplant survival, "

the authors write. " The models presented here can be used to derive scores

that are proportional to the excess risk of graft loss after liver

transplantation for potential donors, recipients, or donor/recipient

combinations. The models may be used to inform liver transplant candidates

and their doctors what posttransplant survival would be expected when a

given donor is offered and may be particularly helpful for marginal or

high-risk donors. "

Study limitations include inability to adjust for each individual center;

inability to verify the accuracy of the data; exclusions of persons with

missing data; and the possibility that predictors of survival might have

changed slightly during the 10-year study period.

" Ultimately, risk scores and predicted survivals determined from such models

may be an objective

way to assess the risk of a given liver donor, recipient, or donor/recipient

combination, " the authors conclude. " If two donors are expected to be

available at approximately the same time, it would be more equitable for the

recipient with worse predicted post-transplant survival to receive the donor

with the better predicted survival and vice versa since that would make the

post-transplant survival of the two recipients more similar. "

The American College of Gastroenterology Junior Faculty Development Award,

Veterans Affairs Northwest Hepatitis C Resource Center, Veterans Affairs

Puget Sound Health Care System Research Enhancement Award Program, and the

Health Resources and Services Administration helped fund this study.

In an accompanying editorial, Ignazio R. Marino, MD, FACS, from the

Jefferson University Hospital in Philadelphia, Pennsylvania, recommends a

large prospective study of liver transplant candidates to help optimize

allocation criteria and to define when a prospective donor should not be

used for a prospective recipient.

" If candidates for [liver transplant] can be stratified into different risk

categories at the time of the actual organ allocation, the inevitable

question arises: Should we try to match donors and recipients? " Dr. Marino

writes. " In addition, should we try to implement rules to assess when a

patient is too sick for [liver transplant] and have uniform delisting

criteria?.... We might not be ready to match donors and recipients yet, but

this procedure should be our ultimate goal. "

Liver Transplantation. 2006;12(11):1574-1576, 1594-1606

Laurie Barclay, MD is a freelance reviewer and writer for Medscape.

Medscape Medical News 2006

http://www.medscape.com/viewarticle/547221?src=mp

_________________________________________________________________

Add a contact to Windows Live Messenger for a chance to win a free

trip!

http://www.imagine-windowslive.com/minisites//default.aspx?locale=en-us & hmt\

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