Plasma Volume Score for Early Risk Stratification Following Heart Transplantation: An Exploratory Observational Study

Background/Objectives: Plasma volume score (PVS) is a simple integrative surrogate marker derived from body weight and hematocrit that may capture plasma volume expansion, congestion, and overall disease severity. Previous studies have demonstrated its prognostic value in patients with heart failure and other cardiovascular populations. However, the clinical relevance of pre-transplant PVS in heart transplant recipients remains unknown. Methods: We retrospectively analyzed 375 adult heart transplant recipients. Baseline PVS was calculated before transplantation and analyzed as both a continuous and categorical variable using a predefined cut-off of 3.1. The primary endpoint was 1-year all-cause mortality. Secondary endpoints included overall survival, 30-day mortality, and post-transplant dialysis. Results: Median baseline PVS was -5.4 (interquartile range -12.4 to 2.6), and 88 patients (23.5%) had a PVS ≥ 3.1. In multivariable linear regression analysis, elevated PVS was independently associated with lower estimated glomerular filtration rate, ventricular assist device support, pre-transplant infection, clinical congestion, admission status, bilirubin levels, and body mass index (all p < 0.05). Patients with PVS ≥ 3.1 had significantly lower 1-year survival compared with patients with PVS < 3.1 (81.8% vs. 90.9%; log-rank p = 0.017). Higher PVS was associated with increased 1-year mortality (hazard ratio [HR] 1.028 per PVS unit, 95% confidence interval [CI] 1.001-1.055; p = 0.044). Elevated PVS was additionally associated with post-transplant dialysis (OR 1.14 per 5-point increase, 95% CI 1.01-1.28; p = 0.036). No significant association was observed between PVS and overall long-term survival or PGD. Conclusions: Elevated pre-transplant PVS is associated with impaired 1-year survival and increased risk of post-transplant dialysis after heart transplantation. As an inexpensive and readily available marker of congestion and disease severity, PVS may provide useful information for pre-transplant risk stratification.