Pre-Heart Transplant Spirometry Predicts Post-Transplant Survival

Abstract

Lung disease is common in the advanced heart failure population. While pulmonary function testing (PFT) is typically performed as part of a heart transplant evaluation, little is known regarding the prognostic utility of PFTs for outcomes after transplantation. We evaluated whether PFT parameters correlated with survival, length of stay, or time on ventilator following heart transplantation. International Society for Heart and Lung Transplantation (ISHLT) Thoracic Organ Transplant (TTX) registry data was combined with single-center data from the University of Nebraska Medical Center. Cox proportional hazard modeling was used to evaluate univariate and multivariate predictors of survival. A total of 1083 patients (802 from a total of 62,327 from the TTX registry, 281 from the UNMC database) had pre-transplant PFT data available for evaluation. At the time of transplant, the mean age was 50.6 (± 14.5) years, 24.2% were female, 51% had a history of tobacco use, and 8% had a history of chronic obstructive pulmonary disease. Forced expiratory volume in 1 second (FEV1) < 50% of predicted and forced vital capacity (FVC) < 50% of predicted each had significantly higher mortality within the first 5 years post-transplant (p < 0.0001 and p=0.0001, respectively) compared to patients with FEV1 or FVC 50-70% or > 70% (Figure 1). FEV1/FVC < 0.7 and DLCO < 60% predicted were not associated with increased mortality. FEV1 and FVC below 50% of predicted both had longer lengths of stay (p=0.0005 for FEV1 and <0.0001 for FVC), but were not associated with more time on the ventilator. After adjusting for male gender, age, body mass index, smoking history, COPD, creatinine, albumin, and total bilirubin, either FEV1 or FVC < 50% remained independent predictors of mortality with a hazard ratio of 2.65 (p < 0.0001, 95% CI 1.6, 4.3). Abnormal pulmonary function (FEV1 or FVC < 50% prior to transplantation is associated with increased mortality and longer length of stay following transplant.