A pathologic analysis of the outcome following heart-lung transplantation: an autopsy study of 22 recipients

Pathologic correlates of bronchiolitis obliterans syndrome in pulmonary retransplant recipients

RATIONALE

The main hindrance to long-term success of lung transplantation is bronchiolitis obliterans syndrome (BOS), generally thought to be a manifestation of chronic allograft rejection. BOS is associated histologically with epithelial injury, bronchocentric mononuclear inflammation, and fibrosis of small airways known as bronchiolitis obliterans (BO). Few studies have directly compared clinical, radiographic, and histologic findings of BOS and BO, particularly in the era of improved immunosuppression and infection prophylaxis. Patients undergoing pulmonary retransplantation for BOS provide a unique opportunity to investigate these relationships.

METHODS

All patients who underwent pulmonary retransplantation for BOS from 1992 to 2004 at Duke University Medical Center were reviewed. Pathology findings in explanted lung allografts were compared with clinical, radiographic, and transbronchial biopsy data.

RESULTS

Over the 12-year study period, 12 patients underwent pulmonary retransplantation for BOS. The median time to BOS was 517 days (intraquartile range, 396 to 819.8 days). BOS scores prior to retransplantation were 2 in 2 patients and 3 in 10 patients. We developed a semiquantitative scoring system for epithelial, inflammatory, and fibrotic changes in affected airways to permit better comparison between BO and BOS. Somewhat surprisingly, only 50% (6 of 12 patients) had severe fibrotic changes, although all had some degree of epithelial injury, fibrosis, or inflammation centered around the bronchi and bronchioles. Furthermore, pathology findings other than BO were present in most explanted allografts and included cholesterol clefts (n = 4), focal invasive aspergillosis (n = 1), interstitial fibrosis (n = 2), and chronic vascular rejection (n = 1).

CONCLUSIONS

In this series of patients with advanced BOS undergoing retransplantation, at least some degree of BO was present in all explanted allografts. However, the degree of epithelial changes, fibrosis, and inflammation present among affected bronchi varied considerably. Furthermore, a wide range of pathologic processes of potential clinical significance were evident in half of the patients. We conclude that significant histologic heterogeneity exists among patients undergoing retransplantation for BOS, potentially contributing to the variability of patient responses to treatment.

Pulmonary embolism on postmortem examination: an under-recognized complication in lung-transplant recipients?

INTRODUCTION

Postmortem reports highlight the importance of factors that individually or collectively limit survival. The prevalence of pulmonary embolism (PE) at autopsy in lung-transplant recipients has not been characterized previously.

OBJECTIVE

We aimed to describe the prevalence of PE, infection, and acute and chronic rejection at autopsy and their respective contributions to death in lung-transplant recipients according to survival posttransplantation.

METHODS

We retrospectively reviewed 126 autopsy reports performed in lung-and heart-lung-transplant recipients between June 1990 and September 2002.

RESULTS

PE was identified at autopsy in 34 (27.0%) of 126 lung- and heart-lung-transplant recipients. The prevalence of autopsy-established PE was highest, at 36.4%, in the early group (1-30 days) compared with 20.0% and 23.8% in the intermediate (31-365 days) and late (>365 days) groups, respectively. Although fungal and viral pneumonia were noted most frequently in the early and intermediate groups, bacterial pneumonia was noted in 32% to 45% of autopsies over the posttransplant period. Acute cellular rejection and bronchiolitis obliterans were present in 29.5% and 2.3%, 40.0% and 17.5%, and 35.7% and 42.9% of patients in the early, intermediate, and late groups, respectively. The most frequent cause of death was bacterial infection.

CONCLUSIONS

The prevalence of PE was highest in mechanically ventilated lung-transplant recipients in the early postoperative period. Heart-lung recipients were at lower risk for PE compared with double- and single-lung recipients. PE may be an under-appreciated complication contributing to respiratory failure in the early postoperative period.