Dynamic intercoronary collateral flow in a patient with variant angina and coronary artery spasm

Intermittent intercoronary collateral flow was observed in a patient with coronary vasospasm associated with variant angina. Collateral flow began almost immediately after total occlusion of the right coronary artery, but did not prevent pain or S-T segment elevation. Some collateral vessels may pre-exist ischemic conditions and flow across these channels may be immediately dependent on the pressure gradient across them.