Association between Pulmonary Hypertension and Outcomes in Heart-Kidney Transplantation

Abstract

<h3>Purpose</h3> The prevalence and severity of pulmonary hypertension (PH) in heart-kidney (HK) transplant candidates are not well-characterized. Additional hemodynamic risk factors (i.e. arteriovenous fistula for hemodialysis access, intermittent volume reduction) are present in HK patients. The current study describes PH severity in this patient population to understand its impact on post-transplant outcomes when compared to isolated heart transplant (HT) patients. <h3>Methods</h3> We searched the UNOS database to identify adult HK and HT recipients who underwent de novo transplantation between 2010-2020. Propensity score matching was used to identify a balanced cohort of HK and HT recipients. Baseline characteristics and invasive hemodynamics were compared between HT and HK. Logistic regression models were constructed to quantify the association of PH with 1-year post-transplant mortality. PH was defined as a mean PA pressure >20 mmHg using the updated hemodynamic classification. <h3>Results</h3> We identified 1392 HK recipients and propensity-matched them with 1392 HT recipients. Clinical covariates except for wait-list time and creatinine were well-balanced <b>(Table 1A).</b> PH was more frequent in HK recipients than HT although both groups had mean PVR < 3 WU. HK recipients had significantly higher pre-transplant PA and wedge pressures, but lower PVR from higher circulating cardiac output. In the propensity-matched cohort, HK recipients had numerically higher 1-year mortality (11.2% vs. 8.5%, p=0.02). Multivariate logistic regression analysis identified PH (OR: 1.89 [1.22 - 2.92], p=0.004)<b>,</b> as an independent predictor of 1-year post-transplant mortality for both HT and HK, with HK PH patients experiencing worse outcomes <b>(Figure 1).</b> <h3>Conclusion</h3> HK recipients have greater PH severity and post-transplant mortality risk when compared with matched HT recipients. Further studies are warranted to better understand PH mechanisms and outcomes in the dual-organ populations.