Evolving Trends and Impact of Waitlist Transfusion on Recipient Outcomes Following Heart Transplantation

Background

This study evaluates the clinical trends, risk factors, and impact of waitlist blood transfusion on outcomes following isolated heart transplantation.

Methods

The UNOS registry was queried to identify adult recipients from January 1, 2014, to June 30, 2022. The recipients were stratified into two groups depending on whether they received a blood transfusion while on the waitlist. The incidence of waitlist transfusion was compared before and after the 2018 allocation policy change. The primary outcome was survival. Propensity score-matching was performed. Multivariable logistic regression was performed to identify predictors of waitlist transfusion. A sub-analysis was performed to evaluate the impact of waitlist time on waitlist transfusion.

Results

From the 21 926 recipients analyzed in this study, 4201 (19.2%) received waitlist transfusion. The incidence of waitlist transfusion was lower following the allocation policy change (14.3% vs. 23.7%, p < 0.001). The recipients with waitlist transfusion had significantly reduced 1-year posttransplant survival (88.8% vs. 91.9%, p < 0.001) compared to the recipients without waitlist transfusion in an unmatched comparison. However, in a propensity score-matched comparison, the two groups had similar 1-year survival (90.0% vs. 90.4%, p = 0.656). Multivariable analysis identified ECMO, Impella, and pretransplant dialysis as strong predictors of waitlist transfusion. In a sub-analysis, the odds of waitlist transfusion increased nonlinearly with longer waitlist time.

Conclusion

There is a lower incidence of waitlist transfusion among transplant recipients under the 2018 allocation system. Waitlist transfusion is not an independent predictor of adverse posttransplant outcomes but rather a marker of the patient's clinical condition. ECMO, Impella, and pretransplant dialysis are strong predictors of waitlist transfusion.