Bronchial circulation in asthma.

Whereas the anatomical changes of the bronchial circulation in response to a wide variety of congenital and acquired cardiopulmonary diseases have been well described, little is known about its functional response. There is growing evidence that the bronchial circulation plays a major role in the pathophysiology of hyperreactive airway disease. The bronchial vascular system appears to be involved in mediator transport to and from target tissues in the airway wall, in the development of airway wall edema which may contribute to airflow obstruction, and in heat and water exchange in the tracheobronchial tree. Although our current understanding of these functions is rather sketchy, enough is known to outline the contributions of the bronchial, i.e. the systemic circulation to the mechanisms of bronchial asthma.