Impact of combined heart and lung transplantation on bronchiolitis obliterans syndrome, cardiac allograft vasculopathy, and long-term survival

BACKGROUND: Evidence from animal studies and small case series suggests that primary graft dysfunction occurs less often following combined organ transplantation than following isolated organ transplantation. In this large-scale national registry study, we aimed to investigate whether survival and the rates of bronchiolitis obliterans syndrome (BOS) and coronary allograft vasculopathy (CAV) are affected by simultaneous heart and/or lung transplantation (HLTx). METHODS: Clinical data from the United Network of Organ Sharing database were retrospectively reviewed to identify transplant-naive patients who had undergone heart and/or lung transplantation between 1987 and 2016. The comparisons were conducted for isolated vs combined organ transplant. The outcomes included all-cause mortality, as well as the incidence of BOS and CAV RESULTS: Of the 98,310 patients reviewed, 63,976, 1,189, and 33,145 had received isolated heart transplantation (iHTx) (65%), HLTx (1%), and isolated lung transplantation (iLTx) (34%), respectively. In the early post-operative period, the mortality rates were higher after HLTx than after iHTx or iLTx (on crude and propensity score–matched analyses). However, the adjusted hazard risk for mortality associated with HLTx was significantly lower relative to the iLTx-associated risk beyond 3 years postoperatively, and similar relative to the iHTx-associated risk beyond 7 years postoperatively. On both crude and adjusted analyses, the incidence of BOS and CAV was significantly lower after HLTx than after iHTx or iLTx (p < 0.001 for all comparisons). CONCLUSIONS: Combined (rather than single) organ transplantation may provide immunoprotective benefits enhancing long-term survival and attenuating the risk of BOS and CAV.