Pulmonary Vascular Resistance Predicts Mortality and Graft Failure in Transplantation Patients With Portopulmonary Hypertension

Portopulmonary hypertension (POPH) is a pulmonary vascular disease associated with significant morbidity and mortality in those with liver disease, conferring a higher mortality in patients awaiting liver transplantation (LT). Although not a transplant indication, patients with POPH can experience significant clinical improvement following LT, and those maintaining a mean pulmonary artery pressure (MPAP) <35mm Hg and a pulmonary vascular resistance (PVR) <5 Woods units (WU) are granted additional listing points to expedite LT. The effect of POPH on posttransplant outcomes such as mortality and graft failure, however, is not well defined. We performed a retrospective cohort study of the US Organ Procurement and Transplantation Network database of all adult patients who underwent LT between January 1, 2006, and December 1, 2020. Using adjusted accelerated failure time models, we examined the relationship between a diagnosis of POPH and outcomes following LT and the relationship between pre-LT hemodynamics and post-LT survival (alive with a functioning graft) in patients with POPH. Compared with those undergoing transplants without exception points, patients with POPH had comparable post-LT survival rates but were significantly more likely to have graft failure. Both pre-LT MPAP and PVR predicted post-LT survival in POPH, with a pre-LT PVR of ≥1.6 WU, more than doubling the hazard for mortality (death or a nonfunctioning graft; coefficient, 2.01; standard error, 0.85; hazard ratio, 2.21; P = 0.02). POPH may confer a significantly higher risk of post-LT graft failure compared with patients with cirrhosis without POPH, and a pre-LT PVR of ≥1.6 WU may predict post-LT survival. Further investigation into the relationship between pre-LT hemodynamics, right ventricular function, and post-LT outcomes of mortality and graft failure in POPH is needed.

High early cardiovascular mortality after liver transplantation

Cardiovascular disease (CVD) contributes to excessive long-term mortality after liver transplantation (LT); however, little is known about early postoperative CVD mortality in the current era. In addition, there is no model for predicting early postoperative CVD mortality across centers. We analyzed adult recipients of primary LT in the Organ Procurement and Transplantation Network (OPTN) database between February 2002 and December 2012 to assess the prevalence and predictors of early (30-day) CVD mortality, which was defined as death from arrhythmia, heart failure, myocardial infarction, cardiac arrest, thromboembolism, and/or stroke. We performed logistic regression with stepwise selection to develop a predictive model of early CVD mortality. Sex and center volume were forced into the final model, which was validated with bootstrapping techniques. Among 54,697 LT recipients, there were 1576 deaths (2.9%) within 30 days. CVD death was the leading cause of 30-day mortality (40.2%), and it was followed by infection (27.9%) and graft failure (12.2%). In a multivariate analysis, 9 significant covariates (6 recipient covariates, 2 donor covariates, and 1 operative covariate) were identified: age, preoperative hospitalization, intensive care unit status, ventilator status, calculated Model for End-Stage Liver Disease score, portal vein thrombosis, national organ sharing, donor body mass index, and cold ischemia time. The model showed moderate discrimination (C statistic = 0.66, 95% confidence interval = 0.63-0.68). In conclusion, we provide the first multicenter prognostic model for the prediction of early post-LT CVD death, the most common cause of early post-LT mortality in the current transplant era. However, evaluations of additional CVD-related variables not collected by the OPTN are needed in order to improve the model's accuracy and potential clinical utility.

Program-specific reports: implications and impact on program behavior

PURPOSE OF REVIEW

Measuring and monitoring transplant center performance is vital to ongoing quality assessment and performance improvement initiatives geared toward ensuring optimal care for patients with end-stage organ failure. The impact of regulatory oversight on transplant center behavior and programmatic decision-making is complex.

RECENT FINDINGS

Program-specific reports (PSRs) are published by the Scientific Registry for Transplant Recipients (SRTR) and are publically available for use by a variety of stakeholders, including patients, regulators, insurers, and care providers. PSRs have been both groundbreaking and controversial. The principal areas of concern relate to potential unintended consequences of PSRs, limitations in both the data collected by the registry and the currently used statistical methodology employed by the SRTR for risk adjustment, and the subsequent impact on transplant program behavior.

SUMMARY

PSRs, which serve the purposes of fueling ongoing performance improvement initiatives and informing consumers and payers by fostering transparency in the communication of risk, also involve trade-offs because of their unintended use for regulatory oversight and subsequent impact on transplant center behavior. Future research is necessary to improve data integrity and risk-adjustment methodologies which will enhance regulation and preserve access to transplantation among vulnerable patient populations.