Coronary collateral blood flow in a patient with angiographically normal coronary arteries.

A 36-year-old man underwent coronary arteriography for evaluation of chest pain. His coronary arteries were smooth and free of obstructive disease. Selective right coronary injection revealed a large collateral vessel that opacified distal and proximal portions of the left circumflex coronary artery. Our case supports the view that coronary collateral vessels may occur in the absence of obstructive lesions.