Upload
magnus-ford
View
216
Download
2
Tags:
Embed Size (px)
Citation preview
Characteristics Associated with Liver Graft Failure:
The Concept of a Donor Risk Index
American Journal of Transplantation 2006; 6: 783–790S. Fenga, N.P. Goodrich,
J.L. Bragg-Gresham, D.M. Dykstra,J.D. Punch, M.A. DebRoy, S.M. Greenstein
R.M. Merion
Ri 張立禹
Introduction
Increasing organ utilization / Progressive shortage of donor organs
Increasing awareness of potential impact of aggressive organs utilization
The Model for End-Stage Liver Disease (MELD): solely based upon transplant candidate
Quantitative descriptions of organ quality, solely based upon donor characteristics
Materials & Methods (Data source)
Data source: the Scientific Registry of Transplant Recipients (SRTR)
Duration: 1998/1/1-2002/12/31
20,023 transplants
Deceased donor
Multiple organ transplants: excluded
Materials & Methods (Analytic methods)
Cox regression models
Time to graft failure: Transplantation to Retransplantation/ Recipient death
The median follow-up time: 3 years
Age, sex, race, ethnicity……
Recipient and transplant factors: adjusted to isolate the impact of donor characteristics.
Results -Donor and recipient characteristics-
Results -Risk factors for graft failure-
7 risk factors has significant association with liver graft failure:
1. Age
2. Race
3. Height
4. Cause of death (COD): CVA
5. COD: Other (not trauma/ CVA/ anoxia)
6. Donation after cardiac death (DAD)
7. Split/ Partial graft
“Donor Demographic Characteristics”
Age:
>40 years- increased risk of graft failure
>60 years– the strongest risk factor for graft failure
Race:
African-American– 19% higher than white donor
Height:
Stronger than body weight
“Cause and Type of Donor Death”
COD CVA:
COD Other:
Both have higher risk of graft failure (16% and 20%)
DCD:
51% higher risk of graft failure
Split/ Partial graft:52% higher risk of graft failure
--Two Transplant Factors--
Cold ischemia time:
↑1% risk of graft failure/ addition hour
Sharing outside of the local donor service area:
Outside the local area: ↑11%
Nationally shared: ↑28%
Results -Transplants according to donor risk index-
RR of graft failure vs donor factor alone
Donor risk index = exp[(0.154 if 40≤ age <50) + (0.274 if 50≤ age <60) + (0.424 if 60≤ age <70) + (0.501 if 70 ≤ age) +(0.079 if COD = anoxia) + (0.145 if COD = CVA) + (0.184 if COD = other) + (0.176 if race = African American) + (0.126 if race = other) +(0.411 if DCD)+(0.422 if partial/split)+(0.066 ((170–height)/10))+(0.105 if regional share)+(0.244 if national share)+(0.010×cold time)].
Results -Recipient characteristics associated with utilization
of grafts with higher donor risk index -More likely to receive higher risk donor index organs
Older
Youngest
Woman
Recipient without HCV
Low disease severity (MELD score 10-14)
Results -Liver disposition by donor risk index categories-
↑Risk index ,↑Higher discard rate
Discard rate:Risk index > 1.5 twice than risk index ≤ 1.1
Discussion
7 donor & graft characteristics are significantly and independently associated with graft failure.
Could compare the relative risk and the candidate’s disease severity at the time of organ offer
Age:
A negative factor
Donor age > 40 years are increasing (1988: 13%; 2003: 54%)
Reflect the increasing disparity of organ demand and supply
Split/partial or DCD grafts:
Associated with >50% risk of graft failure
Only 2.0% and 1.1% of all transplantation now, but will likely continue to increase
-Other Risk Factor-
Not achieve significance in this study:Female sex, Obesity,↑Liver function test (AST/ALT), hypotension/ increased pressor use, and ↑[Na+]
Macrosteatosis and Cold ischemia timeBoth strongly associate with outcome in other study
Macrosteatosis:
Not easily detect while organ offering (frozen section)
Not significantly associate with outcome in this study
Cold ischemia time
Estimated while organ offer
Included in this study’s donor risk index
Ideal graft (ex: from donor <40 years, brain death secondary to trauma or anoxia)
A relatively homogenous outcome group
Non-ideal graftA heterogeneous outcome group
The multitude of possible risk factor combinations presented by the donor pool
The risk continues to increase:
Age of donor↑, Frequency of DCD donor↑, Split/ partial grafts↑
Ironic, split graft have been seen as ideal if transplanted as a whole organ
Split graft: increased the patient transplanted & the net gain of life year
-The candidate who have the greatest risk without graft transplantation-
Have the greatest survival benefit form transplantation
May have disproportionately poorer outcomes with higher risk graft
Compare to delayed transplantation, immediate transplantation with graft bearing a 50% risk of primary liver failure provide a higher 1-year survival rate
-Discard Rate-
Higher discard rate for organs with higher donor risk index, but modest (3.1% in risk index of 1.0 to 12.5% in risk of 2.0 or greater)
→ the willingness to accept increased risk from suboptimal donor quality (more imminent consideration of candidate mortality in the absence of transplantation)
The decision to accept either the risk of transplantation or the risk of waiting must be decide rationally.
The risk posed by the graft offering
The risk of death from progressive liver disease
This study provides an important quantitative assessment of relative risk of every potential graft, based upon donor and graft characteristics
Thanks For Your Attention