Assessment of Heart Transplant Waitlist Time and Pre- and Post-transplant Failure: A Mixed Methods Approach

Abstract

Background: Over the past two decades, there have been increasingly long waiting times for heart transplantation. We studied the relationship between heart transplant waiting time and transplant failure (removal from the waitlist, pretransplant death, or death or graft failure within 1 year) to determine the risk that conservative donor heart acceptance practices confer in terms of increasing the risk of failure among patients awaiting transplantation.

Methods: We studied a cohort of 28,283 adults registered on the United Network for Organ Sharing heart transplant waiting list between 2000 and 2010. We used Kaplan-Meier methods with inverse probability censoring weights to examine the risk of transplant failure accumulated over time spent on the waiting list (pretransplant). In addition, we used transplant candidate blood type as an instrumental variable to assess the risk of transplant failure associated with increased wait time.

Results: Our results show that those who wait longer for a transplant have greater odds of transplant failure. While on the waitlist, the greatest risk of failure is during the first 60 days. Doubling the amount of time on the waiting list was associated with a 10% (1.01, 1.20) increase in the odds of failure within 1 year after transplantation.

Conclusions: Our findings suggest a relationship between time spent on the waiting list and transplant failure, thereby supporting research aimed at defining adequate donor heart quality and acceptance standards for heart transplantation.

Figure 1

Relationship between heart transplant candidate blood type and time to transplantation, stratified on priority status. Type AB candidates receive a heart faster than Type O candidates.

Figure 2

Kaplan-Meier curves for death on the waitlist. Curves are adjusted for transplantation using inverse probability censoring weights, Type 1A patients (the sickest) experience the fastest drop in survival during the first 60–90 days after being listed.