Changes in bloodstream infections in heart transplant recipients following the allocation guidelines change.

In 2018, the orthotopic heart transplant (OHT) allocation policy in the United States changed to prioritize more critically ill candidates, including those supported with temporary mechanical circulatory support (tMCS). This study evaluated changes in posttransplant bloodstream infection (BSI) rates following the OHT allocation change. We conducted a retrospective cohort study of OHT recipients at 2 large United States transplant centers from January 1, 2015, to December 31, 2022. Recipients were followed 90 days post-OHT for BSIs. The association between policy era and BSIs was evaluated using multivariable Cox regression with mediation analysis to explore the effect of tMCS. There were 895 OHT recipients with a >2.5-fold increase in pretransplant tMCS after the policy change. Ninety-five recipients developed BSIs (10.6%). OHT in the postpolicy era was associated with a 2.3-fold increased hazard of BSI (P = .002). Mediation analysis showed tMCS explained some, but not all, of the increased BSI risk after change. One-year mortality and graft failure were similar across the 2 policy eras, although there was a significant decrease in 1-year rejection following the change (P < .001). Overall, post-OHT BSI risk doubled following the allocation change, which is not fully explained by tMCS. Additional studies are needed to further investigate factors contributing to BSI risk.