Acquired coronary-to-bronchial artery communication: a possible cause of coronary steal.

An unusual case of an acquired coronary-to-bronchial artery communication is presented. Collateral flow to the lung was provided by the right coronary circulation following obstruction of pulmonary blood flow by chronic pulmonary emboli. A coronary steal phenomenon may have caused an exacerbation of cardiac symptoms by further reducing already compromised coronary blood flow in a patient with atherosclerotic coronary artery disease.