Predictors of Survival in Patients with Primary Pulmonary Hypertension Wait-listed for Lung Transplantation
Roger D. Yusen, M.D., M.P.H.
Study Question: What is the association between baseline characteristics of patients with PPH evaluated for lung transplantation and survival after wait-listing for lung transplantation?
Primary pulmonary hypertension (PPH) is a disease of unclear etiology in which patients progressively deteriorate and eventually die from right heart failure. A 1987 NIH registry demonstrated that the median survival after diagnosis was 2.8 years. Though medical therapy has been shown to have a significant impact on the short-term quality of life and survival of patients with PPH, the long-term outcomes are poor. A few studies have indirectly suggested that lung transplantation prolongs survival in patients with PPH. Unfortunately, the median wait-time for lung transplantation in the United States is approaching two years. Thus, a significant proportion of patients with PPH die while awaiting lung transplantation. In addition, lung transplantation has had less favorable outcomes for patient with PPH when compared to patients with other end-stage lung diseases.
The United Network for Organ Sharing (UNOS) sets policies and criteria for organ allocation, manages the national transplant waiting list, and assigns donor lungs to recipients. Currently, allocation of donor lungs to recipients is based mainly on recipient time spent on the lung transplant wait-list, in addition to matching of donors to recipients in terms of height and blood type. The Federal Government has mandated that UNOS create status categories for medical urgency. In other words, sicker patients should undergo transplantation before more healthy patients, with an overall goal of improving overall survival. This mandate has not been implemented because the research to date has been inadequate.
In order to develop a new organ allocation system for patients wait-listed for lung transplantation, variables predictive of survival need to be identified. The impact of each variable on survival, while controlling for the effects of other variables, needs to be quantified. Models are needed to assess the impact of changing the organ allocation system in order to decrease mortality of patients awaiting lung transplantation. In addition, it will be important to assess whether transplanting sicker patients on the wait-list will lead to improved outcomes following transplantation. Research leading to a change in the organ allocation policy will have a high impact in terms of quality of life and survival. This study will provide key data from the largest lung transplant program in the United States to answer the following question.
Primary pulmonary hypertension (PPH) is a disease of unclear etiology in which patients progressively deteriorate and eventually die from right heart failure. A significant proportion of patients with PPH die while awaiting lung transplantation. This study aimed to assess the association between baseline characteristics of patients with PPH evaluated for lung transplantation and survival after wait listing for lung transplantation ... Read the full Final Report.