Low-Dose Valganciclovir for Primary Cytomegalovirus Prophylaxis After Heart Transplant: A 10-Year Experience

Due to the hematologic toxicities associated with standard-dose valganciclovir (VGCV), low-dose (LD) VGCV has been proposed as an alternative, primarily in abdominal transplant recipients. Data on LD VGCV outcomes in heart transplant recipients (HTR) remain limited.

This single-center, retrospective, stimulating cohort study describes adult, cytomegalovirus (CMV) D+/R- and R+ HTR transplanted between January 1, 2013 and September 30, 2022 and maintained on, at most, VGCV 450 mg daily for primary CMV prophylaxis.

A total of 338 HTR were reviewed, of whom 80 CMV D+/R- and 154 R+ HTR met criteria for inclusion. Of the 234 HTR, the median age was 56 years, the mean body mass index (BMI) was 26.9 kg/m², and 93 (39.7%) had an estimated glomerular filtration rate ≥60 mL/min/1.72 m² at post-transplant month 12. Breakthrough (BT) CMV occurred in six (2.6%) individuals, exclusively among CMV D+/R- HTR. Two cases were complicated by CMV end-organ disease (retinitis, colitis) with ganciclovir (GCV) resistance. Leukopenia occurred in 67.1% of the total cohort, necessitating frequent VGCV and mycophenolate adjustments.

This is the largest report of LD VGCV use in HTR. Despite reduced VGCV exposure, HTR remain at high risk for cytopenias. Regardless of potential risk factors, including a high prevalence of overweight BMI and adequate renal function, LD VGCV was associated with expected rates of BT CMV and CMV resistance, suggesting LD VGCV could be considered in HTR. Identification of CMV end-organ disease and GCV resistance suggests that LD VGCV could be considered cautiously in CMV D+/R- HTR.