The role of donor age and ischemic time on survival following orthotopic heart transplantation.
BACKGROUND
The advances in immunotherapy, along with a liberalization of eligibility criteria have contributed significantly to the ever increasing demand for donor organs. In an attempt to expand the donor pool, transplant programs are now accepting older donors as well as donors from more remote areas. The purpose of this study is to determine the effect of donor age and organ ischemic time on survival following orthotopic heart transplantation (OHT).


METHODS
From April 1981 to December 1996 372 adult patients underwent OHT at the University of Western Ontario. Cox proportional hazards models were used to identify predictors of outcome. Variables affecting survival were then entered into a stepwise logistic regression model to develop probability models for 30-day- and 1-year-mortality.


RESULTS
The mean age of the recipient population was 45.6 +/- 12.3 years (range 18-64 years: 54 < or = 30; 237 were 31-55; 91 > 56 years). The majority (329 patients, 86.1%) were male and the most common indications for OHT were ischemic (n = 180) and idiopathic (n = 171) cardiomyopathy. Total ischemic time (TIT) was 202.4 +/- 84.5 minutes (range 47-457 minutes). In 86 donors TIT was under 2 hours while it was between 2 and 4 hours in 168, and more than 4 hours in 128 donors. Actuarial survival was 80%, 73%, and 55% at 1, 5, and 10 years respectively. By Cox proportional hazards models, recipient status (Status I-II vs III-IV; risk ratio 1.75; p = 0.003) and donor age, examined as either a continuous or categorical variable ([age < 35 vs > or = 35; risk ratio 1.98; p < 0.001], [age < 50 vs > or = 50; risk ratio 2.20; p < 0.001], [age < 35 vs 35-49 versus > or = 50; risk ratio 1.83; p < 0.001]), were the only predictors of operative mortality. In this analysis, total graft ischemic time had no effect on survival. However, using the Kaplan-Meier method followed by Mantel-Cox logrank analysis, ischemic time did have a significant effect on survival if donor age was > 50 years (p = 0.009). By stepwise logistic regression analysis, a probability model for survival was then developed based on donor age, the interaction between donor age and ischemic time, and patient status.


CONCLUSIONS
Improvements in myocardial preservation and peri-operative management may allow for the safe utilization of donor organs with prolonged ischemic times. Older donors are associated with decreased peri-operative and long-term survival following. OHT, particularly if graft ischemic time exceeds 240 minutes and if these donor hearts are transplanted into urgent (Status III-IV) recipients.
Del Rizzo
D F
DF
London Health Sciences Centre, University of Western Ontario, London, Canada.
Menkis
A H
AH
Pflugfelder
P W
PW
Novick
R J
RJ
McKenzie
F N
FN
Boyd
W D
WD
Kostuk
W J
WJ
D000206:Actuarial Analysis; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D009202:Cardiomyopathies / Q000601:surgery; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D005544:Forecasting; D016027:Heart Transplantation / Q000502:physiology*; D006801:Humans; D007511:Ischemia / Q000503:physiopathology; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D017202:Myocardial Ischemia / Q000601:surgery; D016017:Odds Ratio; D009926:Organ Preservation; D011336:Probability; D016016:Proportional Hazards Models; D015996:Survival Rate; D013997:Time Factors; D014019:Tissue Donors; D016896:Treatment Outcome