Coronary-to-pulmonary artery shunts via the bronchial artery: analysis of cineangiographic studies.

Coronary-to-pulmonary artery shunts via the bronchial artery (CA-BA-PA shunts) were observed in 16 of 2,922 consecutive patients who underwent selective coronary cineangiography. Underlying diseases included Takayasu arteritis (n = 8), chronic pulmonary inflammatory diseases (n = 4), pulmonary thromboembolism (n = 2), pulmonary artery tumor (n = 1), and tetralogy of Fallot with pulmonary atresia (n = 1). Ventilation-perfusion scans were available in 15 of the 16 patients. Mismatched defects were identified in 11 patients, and matched defects were identified in four. Bronchial-to-pulmonary artery shunts were detected on selective bronchial angiograms and/or thoracic aortograms in 13 patients. Feeding arteries of the CA-BA-PA shunts included left atrial branches (n = 13), right sinus node branches (n = 7), left sinus node branches (n = 2), right conal branch (n = 1), left conal branch (n = 1), and posterolateral branches (n = 2). These coronary branches seemed to serve as collateral vessels from a coronary arterial system with a higher pressure to a pulmonary arterial system with a lower pressure in conditions of decreased pulmonary flow or in cases of chronic pulmonary inflammatory disease. The importance of the coronary artery along with other superior thoracic collateral networks in contributing to the development of shunts to the pulmonary artery is underscored.