Joost Felius

Background Little is known about the relationship between cytomegalovirus (CMV) infections and donor‐derived cell‐free DNA (dd‐cfDNA) in heart transplant recipients. Methods In our study, CMV and dd‐cfDNA results were prospectively collected on single‐organ heart transplant recipients. If the CMV study was positive, a CMV study with dd‐cfDNA was repeated 1‐3 months later. The primary aim was to compare dd‐cfDNA between patients with positive and negative CMV results. Results Of 44 patients enrolled between August 2022 and April 2023, 12 tested positive for CMV infections, 25 were included as controls, and seven patients with a viral infection without CMV were excluded. Baseline characteristics did not differ significantly between CMV‐positive and CMV‐negative patients with the exception of a later median time post‐transplant in the CMV‐positive group (253 days vs. 120 days, p = .03). Dd‐cfDNA levels were significantly higher in patients with CMV infections compared to those without ( p < .001) with more patients in the CMV positive group showing dd‐cfDNA results ≥.12% (75% vs. 8%, p < .001) and ≥.20% (58% vs. 8%, p = .002). Each 1 log 10 copy/ml reduction in CMV viral load from visit 1 to visit 2 was associated with a.23% reduction in log 10 dd‐cfDNA ( p = .002). Conclusion Our findings suggest that active CMV infections may raise dd‐cfDNA levels in patients following heart transplantation. Larger studies are needed to validate these preliminary findings.