Outcomes after listing with a requirement for a prospective crossmatch in pediatric heart transplantation

Allosensitization is associated with inferior waitlist outcomes in pediatric heart transplant candidates, presumably because of the requirement for a negative prospective crossmatch. However, there are no reports of heart transplant candidate outcomes according to prospective crossmatch requirements.

We analyzed data on all children listed for isolated heart transplantation from 1995 to 2009 in the USA according to prospective crossmatch requirement (PXMR). Primary objectives were to describe the prevalence of PXMR at and during listing and to compare waitlist and post-transplant survival for patients based on PXMR. Patients with a PXMR during listing include those with a PXMR at the time of listing as well as those who were designated by the listing center as needing a prospective crossmatch at some point after being placed onto the waitlist.

Among 6,343 listed children, 7.7% had a requirement for a prospective crossmatch at the time of listing and 11.8% had a requirement for a prospective crossmatch during listing. After controlling for risk factors associated with inferior survival, PXMR at listing was associated with increased waitlist mortality (HR 1.32, 95% CI 1.10 to 1.56; p = 0.003). Recipients with a PXMR during listing more commonly had a positive DSXM (22.1% vs 10.3%, p < 0.0001), as did recipients who carried a PXMR throughout listing (21.7% vs 11.3%, p = 0.004). However, there was no significant difference in post-transplant survival on the basis of a PXMR during listing (HR 1.04, 95% CI 0.87 to 1.25; p = 0.67). Nearly 30% of recipients with a PXMR during listing had a peak pre-transplant PRA ≤ 10%.

PXMR increases the likelihood of death while awaiting, but not after, pediatric heart transplantation. Further study is necessary to understand how PXMR is applied, and changes, after listing for pediatric heart transplantation.