Transpulmonary gradient as a predictor for outcomes after lung transplantation

Abstract

Background: End stage lung disease (ESLD) is commonly associated with pulmonary hypertension (PHTN). In a donor restrictive environment, offering patients single over double lung transplants could increase organ utilization. However, there isn't a clinical consensus on how severe PHTN must be to preclude single lung transplant (SLT) due to poor outcomes. We sought to investigate the predictive value of the transpulmonary gradient (TPG) in SLT in patients with ESLD and PHTN. Methods: We performed a retrospective analysis of the United Network for Organ Sharing database and identified all patients who underwent lung transplantation (LT) from May 2005 to March 2021. Patients were stratified based on their TPG score above or below 25 mmHg. Primary outcomes include 1-year survival assessed by generalized linear mixed modeling.Results: Our analysis showed TPG was associated with 1-year survival but this relationship depended on transplant type (P=0.002) with TPG ≥25 being associated with higher mortality in single (P=0.004), but not double LT (P=0.95). This association was maintained when covarying for numerous clinical factors, as well as when excluding deaths within 90 days of LT (P=0.04).Conclusions: A preoperative TPG >25 was associated with decreased 1-year survival in SLT recipients.The use of preoperative TPG combined with other marks of clinical status can help transplant centers in their decision of offering single vs. double lung transplant in patients with ESLD and PHTN.