National Trends in Heart Donor Usage Rates: Are We Efficiently Transplanting More Hearts?

Abstract

Background It is unclear whether the recent increase in the number of heart transplants performed annually in the United States is only because of higher availability of donors and if it affected recipients' survival. Methods and Results We examined characteristics of donors and recipients from 2008 to 2012 (n=11 654) and 2013 to 2017 (n=14 556) and compared them with 2003 to 2007 (n=10 869). Cox models examined 30-day and 1-year risk of recipients' death post transplant. From 2013 to 2017, there was an increase in the number of transplanted hearts and number of donor offers but an overall decline in the ratio of hearts transplanted to available donors. Donors between 2013 and 2017 were older, heavier, more hypertensive, diabetic, and likely to have abused illicit drugs compared with previous years. Drug overdose and hepatitis C positive donors were additional contributors to donor risk in recent years. In Cox models, risk of death post transplant between 2013 and 2017 was 15% lower at 30 days (hazard ratio [HR] 0.85; 95% CI, 0.74-0.98) and 21% lower at 1 year (HR, 0.79; 95% CI, 0.73-0.87) and between 2008 and 2012 was 9% lower at 30 days (HR, 0.91; 95% CI, 0.79-1.05) and 14% lower at 1 year (HR, 0.86; 95% CI, 0.79-0.94) compared with 2003 to 2007. Conclusions Despite a substantial increase in heart donor offers in recent years, the ratio of transplants performed to available donors has decreased. Even though hearts from donors who are older, more hypertensive, and have diabetes mellitus are being used, overall recipient survival continues to improve. Broader acceptance of drug overdose and hepatitis C positive donors may increase the number and percentage of heart transplants further without jeopardizing short-term outcomes.

Keywords: cardiac failure; cardiac transplantation; donor exclusion; donor screening.

Figure 1. Trends in all heart donor allocation by year.

A, counts over time. B, percentages over time. Results are differentiated based on total donors (black line), transplanted donors (green line), denied donors (blue line), or “other” (eg, used for research; red line) and total number of waitlisted patients (purple line) during the years 1995 to 2018. RR in the trend test represents the relative risk per year from the Poisson regression of counts and the odds ratio per year was calculated from the logistic regression model. OR indicates odds ratio.

Figure 2. Trends in use of HCV‐positive donor hearts by year.

Graphs examining use of total HCV‐positive donor hearts from the years 1995 to 2018. A, the total number of donors who were HCV positive (black line), and number of HCV‐positive hearts transplanted (green line) have increased whereas HCV‐positive hearts declined for transplant (blue line) has leveled off since 2015. B, the percentage of donor hearts accepted for transplant (green line) and declined for transplant (blue line), and since 2015, the percentage of HCV‐positive hearts accepted for transplant has increased. RR represents the relative risk per year from the linear trend parameter of the Poisson model. OR indicates odds ratio.

Figure 3. Trends in use of overdose‐death donors by year.

Graphs examining use of overdose‐death donors (ODD) from the years 1995 to 2018. A, total drug overdose (black line) donors, transplanted donors (green line), and those declined from transplant (blue line). Out of all ODD, number of HCV‐positive hearts transplanted (dotted green line) have increased as well since 2015. B, the percentage of transplanted ODD hearts (green line), ODD hearts declined for transplant (blue line), and in recent years, the percentage of accepted ODD hearts has increased. RR represents the relative risk per year from the linear trend parameter of the Poisson model. OR indicates odds ratio.

Figure 4. Kaplan‐Meier curve examining the different eras.

Kaplan‐Meier curves examining 1‐year all‐cause mortality across the different eras. The referent era (2003–2007) was found to have the worst mortality with the more recent eras having significantly lower 1‐year mortality in comparison.

Figure 5. Risk of death among heart transplant recipient according to donor characteristics and by different time periods.

Forest plot examining the risk of death for recipient associated with each individual donor characteristic in 2008 to 2012 and 2013 to 2017 comparing with 2003 to 2007 is displayed. All models were adjusted with the same covariates used primary adjusted models. Bold P values assess the omnibus 3‐era comparison. Other P values asses the relevant era to the 2003 to 2007 reference era. CV indicates cardiovascular.