Nitroglycerin-induced transient coronary artery occlusion.

Nitroglycerin induced a paradoxical disappearance of a stenosed coronary artery in a 57-year-old man with non-Q wave myocardial infarction. On the coronary angiogram, the left anterior descending coronary artery (with a 95% stenosis) became completely invisible 2 min after 0.3 mg sublingual nitroglycerin. Three minutes later, the artery was opacified again. This transient occlusion may have resulted from a passive collapse of the distal portion of the artery, due to insufficient access of nitroglycerin across the stenotic region.