Venospastic phenomena of saphenous vein bypass grafts: possible causes for unexplained postoperative recurrence of angina or early or late occlusion of vein bypass grafts.

Angina recurred in a 54 year old white man after multivessel coronary artery bypass surgery. Fourteen months after operation the frequency and intensity of his mixed angina increased and cardiac stress testing was positive. Repeat cardiac catheterisation showed that all the bypass grafts were widely patent; however, spasms of a vein graft to right coronary artery system were clearly seen. Treatment with calcium blocking agents and long acting nitrates abolished the symptoms during 16 months of clinical follow up.