Bronchial blood supply after lung transplantation without bronchial artery revascularization

Abstract

Purpose of review: This review discusses how the bronchial artery circulation is interrupted following lung transplantation and what may be the long-term complications of compromising systemic blood flow to allograft airways.

Recent findings: Preclinical and clinical studies have shown that the loss of airway microcirculations is highly associated with the development of airway hypoxia and an increased susceptibility to chronic rejection.

Summary: The bronchial artery circulation has been highly conserved through evolution. Current evidence suggests that the failure to routinely perform bronchial artery revascularization at the time of lung transplantation may predispose patients to develop the bronchiolitis obliterans syndrome.

Figure 1. The dual circulation of airways following lung transplantation

This figure models a single lung transplant recipient and how the normal circulation changes following lung transplantation. (a) Cartoon shows normal overlapping bronchial and pulmonary circulations in nontransplanted lung. Airways are normally supplied by a plexus of vessels receiving contribution from both pulmonary artery and bronchial artery circulations. (b) The highly oxygenated bronchial artery circulation is sacrificed at the time of transplantation. The pulmonary artery circulation may primarily supply airways at this time. The dashed line indicates the anastomosis line of a single lung transplant recipient. (c) Pre-BOS dropout of microvasculature is likely of pulmonary artery origin. (d) Return of small neovessels in established BOS. The small gray line extending beyond the anastomosis line represents a putative de-novo bronchial artery possibly growing into the airway in response to airway hypoxia. This regrowth is not radiologically evident within the first year of lung transplantation. Adapted from [1^••,10].