Abstract 15865: Diastolic Pulmonary Artery Pressure to Pulmonary Capillary Wedge Pressure Gradient (DPG) in Over 5700 Patients With an Elevated Transpulmonary Gradient Does Not Predict Survival After Cardiac Transplantation

Background: The transpulmonary gradient (TPG) has been commonly used to differentiate those patients with true pulmonary vascular disease from those with more passive pulmonary hypertension (PH). However, TPG is influenced by elevations in left atrial pressure as well as cardiac output, and therefore, elevation in the TPG may not always reflect pre-capillary PH. Recently, it has been suggested an elevated diastolic pulmonary artery pressure to pulmonary capillary wedge pressure gradient (DPG) may be better indicator of pulmonary vascular remodeling, and therefore, may be of added prognostic value in patients with PH and an elevated TPG. METHODS: Utilizing the United Network for Organ Sharing (UNOS) database, we retrospectively reviewed all primary adult (age >17 years) orthotropic heart transplant recipients between 1998-2011. All patients with available pre-transplant hemodynamic data measured by right heart catheterization were included (n=25,450). We assessed the prognostic value of DPG on post-transplant graft survival in all patients with PH (mean pulmonary artery pressure ≥ 25mmHg) and an elevated TPG. Survival was assessed by Kaplan-Meier analysis. RESULTS: In patients with PH and a TPG > 12mmHg (n=5,777), there was no difference in survival at up to 5 years post-transplant between high (defined as > 3, >5, >7, or >10mmHg) and low DPG groups (≤ 3, ≤5, ≤7, or ≤10mmHg), p = 0.94, 0.76, 0.29, 0.66, respectively (Figure). Similarly, there was no difference in survival between low and high DPG groups if an elevated TPG was defined as > 15mmHg (n=3,037). Pulmonary capillary wedge pressure was higher in the low DPG groups compared to the high DPG groups. CONCLUSIONS: In the largest analysis to date investigating the prognostic value of DPG, an elevated DPG had no impact on post-transplant survival in patients with PH and an elevated TPG. Although retrospective, these findings urge caution before DPG is incorporated into pre-transplant or PH-related clinical decision making.