Influence of pulmonary hypertension on patients with advanced chronic obstrnctive pulmonary disease prior to lung transplantation

Abstract

Objective To study the influence of pulmonary artery hypertension (PAH) on survival of patients with advanced chronic obstructive pulmonary disease (COPD) on the waiting list of lung transplantation. Methods The characteristics of 143 patients with COPD receiving lung transplantation evaluation from January 2014 to August 2016 were queried. Mild PAH was defined as mean pulmonary artery pressure (mPAP) ≥25 mmHg and severe ≥35 mmHg by right heart catheterization measurements. The incidence of PAH was studied, and the patients were divided to different groups to determine the effect of PAH on survival prior to transplantation on the basis of different definitions of PAH. Kaplan Meier method was used to draw survival curves, and a log-rank test was used to analyze the effect of PAH on survival of COPD patients on the waiting list of pulmonary transplantation. Univariate and multivariate Cox proportional hazard models were performed to test the relationship between each main covariate and the hazard of mortality. The waiting time was tracked from wait list entry date until death or censoring, and the censoring issues were as follows: receiving lung transplantation, removing from the waiting list without transplant, and still wating for donor until the last follow-up day (2016-08-30). Results Of 143 COPD patients, there were 119 males and 24 males, with mean age of 61.73 years old; 46 patients received lung transplantation, and the remaining 97 not; 50 had mPAP ≥25 mmHg and 21 had mPAP ≥35 mmHg. A total of 23 cases (22.88%) died on the waiting list. Thirty-eight patients were removed from the list prior to transplantation, and 36 were still on the waiting list. Kaplan-Meier survival function showed suvival of patients with mild PAH or severe PAH was significantly shorter than that of patients without PAH (P<0.001). Using Cox proportional hazards models, univariate analysis revealed significant differences in survival for mild PAH (HR=2.147, 95%CI 1.429-3.157, P<0.001) and severe PAH (HR=3.458, 95%CI 2.518-4.859, P<0.001). Multivariate Cox models identified significant risk for death for mild PAH (HR=2.518, 95%CI 1.728-3.364, P<0.001) and severe PAH HR=4.027, 95%CI 3.257-4.703, P<0.001). Conclusion The incidence of PAH among COPD patients waiting for lung transplantation was high. PAH is associated with significantly increased risk of death among COPD patients waiting for lung transplantation. Key words: Lung transplantation; Pulmonary hypertension; Chronic obstructive pulmonary disease; Prognosis