Single lung transplantation in patients with severe secondary pulmonary hypertension

Abstract

Background: The optimal transplant strategy for patients with end-stage lung disease complicated by secondary pulmonary hypertension (PH) is controversial. The aim of this study is to define the role of single lung transplantation in this population.

Methods: We performed a retrospective study of lung transplant recipients using the Organ Procurement and Transplantation Network/United Network for Organ Sharing Standard Transplant Analysis and Research registry. Adult recipients that underwent isolated lung transplantation between May 2005 and June 2015 for end-stage lung disease because of obstructive or restrictive etiologies were identified. Patients were stratified by mean pulmonary artery pressure ([mPAP] ≥ or < 40 mm Hg) and by treatment-single (SOLT) or bilateral (BOLT) orthotopic lung transplantation. The primary outcome measure was overall survival (OS), which was estimated using the Kaplan-Meier method and compared by the log-rank test. To adjust for donor and recipient confounders, Cox proportional hazards models were developed to estimate the adjusted hazard ratio of mortality associated with elevated mPAP in SOLT and BOLT recipients.

Results: A total of 12,392 recipients met inclusion criteria. Of recipients undergoing SOLT, those with mPAP ≥40 were shown to have lower survival, with 5-year OS of 43.9% (95% confidence interval 36.6-52.7; p = 0.007). Of recipients undergoing BOLT, OS was superior to SOLT, and no difference in 5-year OS between mPAP ≥ and <40 was observed (p = 0.15). In the adjusted analysis, mPAP ≥40 mm Hg was found to be an independent predictor for mortality in SOLT, but not BOLT recipients. This finding remained true on multivariable analysis. In patients undergoing SOLT, mPAP ≥40 was associated with an adjusted hazard ratio for mortality of 1.31 (1.08-1.59, p = 0.07). In BOLT, mPAP was not associated with increased hazard (adjusted hazard ratio 1.04, p = 0.48).

Conclusions: There is a reduced survival when a patient with severe secondary PH undergoes SOLT. This increased mortality hazard is not seen in BOLT. It appears that a BOLT may negate the adverse effect that severe PH has on OS, and may be superior to SOLT in patients with mPAP over 40 mm Hg.

Keywords: chronic obstructive airway disease; pulmonary fibrosis; pulmonary hypertension; single lung transplant; survival.