Previously undiagnosed variant angina as a cause of chest pain after coronary artery bypass surgery.

Variant angina was diagnosed after coronary artery bypass surgery in six patients over a 22-month period. Although all six patients had at least occasional angina at rest preoperatively, all but one had predominantly exertional angina. After surgery, rest angina with transient ST-segment elevation appeared in all six after an asymptomatic interval of 1 week to 4 years. In two patients the involved artery had not been bypassed, in two patients it was perfused by a patent graft and in two patients the graft to the involved vessel was occluded. Treatment with calcium antagonist drugs (four cases) or isosorbide dinitrate (one case) eliminated symptoms; one patient spontaneously became asymptomatic. The diagnosis of variant angina should be considered when rest angina occurs after bypass surgery, particularly if exertional angina is absent and grafts are patent.