Pulmonary artery pressure and benefit of lung transplantation in adult cystic fibrosis patients

Background The effect of lung transplantation (LTx) in patients afflicted with cystic fibrosis (CF) and pulmonary hypertension (PH) at placement on the waiting list is not well studied. Methods To predict the relationship between initial mean pulmonary artery pressure (MPAP) and hazard ratio (HR) of death after listing associated with LTx in adult patients with CF, the United Network for Organ Sharing database was queried for the years 2005 to 2013. Survival was assessed from waiting list entry until death on the waiting list, death after LTx, or censoring. A multivariate Cox model was performed to estimate the HR of LTx conditional on MPAP at listing. Results Of 1,841 patients with CF, 10% (177) died on the waiting list, 18% (325) were censored without undergoing LTx, and 73% (1,339) underwent transplantation, 361 of whom died after transplantation. A multivariate Cox model of survival since list entry including 1,336 patients found a protective but statistically insignificant benefit of LTx for patients whose MPAP at listing was 25 mm Hg (HR, 0.879; 95% confidence interval [CI], 0.657-1.177; p = 0.388), yet LTx was predicted to be more protective at higher initial MPAP levels, as indicated by the significant interaction term between LTx and MPAP (HR, 0.953; 95% CI, 0.928-0.978; p < 0.001). The predicted LTx HR and 95% CI were protective (HR < 1) at p < 0.05 for patients with MPAP greater than or equal to 30 mm Hg at listing. Conclusions Survival benefit of LTx in CF was increasingly protective at higher MPAP levels, with a severity level of PH established above which a survival advantage of LTx was found.