Risk stratification and survival in patients after liver transplantation: the role of right heart function and dimension
Authors: Deffke P O , Westphal J G , Settmacher U , Schulze P C 
Published: October 2021

Abstract

Background
Liver transplantation (LTx) is often the only treatment strategy in patients with advanced liver disease. Since the donor pool is limited, careful preoperative examination of the cardiac functional status is crucial. Especially the presence of pulmonary hypertension (PH) either coincidental or as part of porto-pulmonary hypertension (PoPHT) is known to play a prognostic role in post-transplant survival and graft durability. However, right heart function itself may play a role even in the absence of PH.

Purpose
We retrospectively evaluated right heart function data acquired during transthoracic echocardiography (TTE) in the evaluation process for LTx listing to identify patient populations at risk for poor long-term prognosis.

Methods
We performed a single-center retrospective cohort study of patients that underwent LTx between 2011 and 2020. All patients ultimately underwent LTx; Survival data were assessed at 90 days, 1 year and 3 years. The waiting period from time of cardiac assessment to the actual operation was blinded. We evaluated right heart end-diastolic diameter (RVEDd), tricuspid annular plane systolic excursion (TAPSE), as well as right atrial area (RAA). We pre-specified cut-offs for abnormal values with RVEDd above 39 mm, TAPSE below 18 mm and RAA above 16 cm2.

Results
We evaluated 351 patients who underwent LTx. 247 data sets were complete and could be included in the primary analysis (mean age 56.3±10.3 years, 75.7% male). Patients had a median Lab-MELD-Score of 14 points (IQR: 10–21 points). 23.8% of patients received a living donor transplant. The left ventricular ejection fraction was not compromised in any of the subjects (mean LVEF: 68.6±9.0%). The median waiting time in days between TTE and LTx was 142 days (IQR: 37–434 days) The primary end-point of mortality occurred in 44 or 17.8% of patients over a Period of three years.
In univariate Cox-regression the pre specified cut-offs for TAPSE and RAA were not associated with a statistically significant survival (HR 0.663, CI: 0.33–1.33, p: 0.25). However, univariate analysis revealed that increased RVEDd was associated with post-LTx survival (HR 1.98, CI: 1.09–3.58, p=0.025) as well as Log-Rank (Mantel-Cox) in the Kaplan-Meier-estimate (Chi2: 5.25, p:0.022). In multivariable analysis including several laboratory values as well as the Lab-Meld-Score (Figure 2), RVEDd group remained the only significant parameter predicting mortality (HR 2.12, CI: 1.02–4.41, p=0.04). The Kaplan Meier analysis showed a significant difference in survival at 3 years of follow-up. Combining right ventricle parameters in a secondary analysis did not provide any additional benefit in predicting survival

Conclusion
Analysis of right heart function and especially dilatation was able to provide additional information concerning long-term outcome post-LTx in this retrospective analysis even when taking into consideration that moderate to severe PH or PoPHT was ruled out beforehand.

Funding Acknowledgement
Type of funding sources: None.