RESUMO
OBJECTIVE: Right ventricular (RV) donor-recipient sizing has been demonstrated to be a sensitive predictor for mortality after heart transplantation. We sought to understand the relationship between donor-recipient RV mass (RVM) ratio and pulmonary vascular resistance (PVR) on outcomes after heart transplantation. METHODS: Adult heart transplant recipients from the United Network for Organ Sharing database were included (N = 42,594). The influence of RVM ratio and PVR on 1-year mortality was assessed by logistic regression after multivariable adjustment. RESULTS: Among transplant recipients, median PVR was 2.4 Wood units (WU) (range, 1.7-3.3 WU) and median RVM ratio was 1.2 (1.0-1.3). Without considering PVR, RVM ratio was highly associated with postoperative dialysis (odds ratio [OR], 0.49; P < .001) and 1-year mortality (OR, 0.64; P < .001). Without considering RVM ratio, PVR was highly associated with 1-year mortality (OR, 1.05; P < .001), but not postoperative dialysis (OR, 0.98; P = .156). When considering both RVM ratio and PVR, the risk associated with each remained significant, but PVR did not modify the effect of RVM ratio on 1-year mortality (RVM ratio × PVR: OR, 0.99; P = .858). To maintain a consistent predicted 1-year mortality, RVM ratio would need to increase by 0.12 for each WU increase in PVR. Secondary analyses found that a 1 WU change in PVR was associated with an 11% increase in mortality risk in RVM ratio mismatched patients (RVM ratio < 1; P = .001), but only a 5% increase in RVM ratio matched patients (RVM ratio ≥ 1; P = .003). CONCLUSIONS: RVM ratio and recipient PVR are independent predictors of 1-year mortality. Still, a larger RV mass may be utilized to mediate the effects of an elevated PVR.
RESUMO
Objective: Implantation of an appropriately sized donor heart is critical for optimal outcomes after heart transplantation. Although predicted heart mass has recently gained consideration, there remains a need for improved granularity in size matching, particularly among small donor hearts. We sought to determine if indexed donor cardiac output is a sensitive metric to assess the adequacy of a donor heart for a given recipient. Methods: A retrospective analysis was performed (2003-2021) in isolated orthotopic heart transplant recipients from the United Network for Organ Sharing database. Donor cardiac output was divided by recipient body surface area to compute cardiac index (donor cardiac index). Predicted heart mass ratio was computed as donor/recipient predicted heart mass. The primary outcome was mortality 1 year after transplant. Results: Among transplant recipients, median donor cardiac output was 7.3 (5.8-9.0) liters per minute and donor cardiac index was 3.7 (3.0-4.6) liters per minute/m2. Predicted heart mass ratio was 1.01 (0.91-1.13). After multivariable adjustment, higher donor cardiac index was associated with lower 1-year mortality risk (odds ratio, 0.92, P = .042). Recipients with predicted heart mass ratio less than 0.80 (n = 255) had a lower median donor cardiac index than those with a predicted heart mass ratio of 0.80 or greater (3.2 vs 3.7, P < .001). As predicted, heart mass ratio became smaller and the association between donor cardiac index and 1-year mortality became progressively stronger. Conclusions: Higher donor cardiac index was associated with a lower probability of 1-year mortality among patients undergoing heart transplantation and served to further quantify mortality risk among those with a small predicted heart mass ratio. Donor cardiac index appears to be an effective tool for size matching and may serve as an adjunctive strategy among small donor hearts with a low predicted heart mass ratio.