Introduction:
The shortage of available donor organs means we must re-consider our current policies on donor selection. There is a broad variation in practice between centers as to the acceptable limit to ischaemia time (IT) in pediatric cardiac transplantation, with no recommendations in international guidelines.
Hypothesis:
We hypothesised that a prolonged ischaemia time was not associated with impaired post-transplant outcomes.
Methods:
Data from the Pediatric Heart Transplantation Society was analysed for all pediatric patients receiving heart transplants (Jan 1993 - June 2019). Transplants were separated into 5 categories depending on the IT (hours):
<
2.4, 2.5-3.4, 3.5-4.4, 4.5-6.0, >6. Risk-adjusted outcomes were assessed by multivariable analysis, adjusting for donor, recipient, and peri-operative characteristics.
Results:
Data for 6,903 transplants were assessed (IT < 2.4 in 980, 2.5-3.4 in 2032, 3.5-4.4 in 2310, 4.5-6.0 in 1162, >6 in 281). In univariate analysis, increasing IT was associated with reduced 1-year survival (90.1%, 87.7% and 84.6%; p<0.001) for the 3.5-4.4, 4.5-6.0 and >6 groups, respectively. Similar findings, of a deleterious association with prolonged IT, were observed for freedom from infection (73.0%, 66.8% and 56.4%; p<0.001), freedom from first rejection (67.4%, 62.6% and 61.0%; p = 0.01) and freedom from haemodynamically compromising rejection (89.1%, 85.4% and 85.3%; p=0.004) at 1-year. No significant differences in the risk of malignancy (p=0.2) and time to first CAV (p=0.08) between the IT groups were noted. We separately analysed the risk of graft failure by multiphase hazards modelling. In adjusted analysis, increasing IT was found to be a risk factor for graft failure (HR: 1.08, 95% CI: 1.00-1.16, p=0.04). Within this model, primary diagnosis was a predictor of the outcome (p<0.001). Exploring this association, an IT of > 6 hours was associated with graft failure in cardiomyopathy (HR: 2.87, 95% CI: 1.34 - 6.15, p=0.007), but not congenital heart disease patients.
Conclusions:
In this large multi-centre cohort study, we found a deleterious association between prolonged IT and post-transplant outcomes. We recommend that an IT greater than 6 hours should be avoided in pediatric cardiac transplantation.
Pre-heart transplantation ECMO support achieved favorable post-transplant outcomes in selected patients.