[Coronary artery spasm during vascular surgery]

A 56-year-old male with arteriosclerosis obliterans was scheduled for aorto-biiliac artery bypass graft surgery. He had episodes of chest pain lasting for several minutes. Preoperative electrocardiogram (ECG) and myocardiac scintigram showed no abnormal findings. Anesthesia was induced with thiopental 225 mg, fentanyl 100 micrograms and tracheal intubation was facilitated with vecuronium 10 mg. Anesthesia was maintained with O2 2 l.min-1, N2O 4 l.min-1, sevoflurane 0.5-1% and epidural injection of 1% mepivacaine 6-10 ml.hr-1. Nitroglycerin was infused at a rate of 0.125 microgram.kg-1.min-1. During surgery, a transient elevation of the ST segment occurred three times in lead II of the ECG. For the first episode with decrease in blood pressure at declamping the external iliac artery, administration of phenyrephrine 100 micrograms improved ST segment elevation in ECG. For the second event with a slight decrease in blood pressure, an increased dose of nitroglycerin decreased ST segment elevation. The third incident with increased blood pressure and heart rate was alleviated by decreasing the dose of dopamine. Postoperative ECG and serum creatine kinase level were within normal limits. These three episodes of ST segment elevation might be due to coronary spasms induced by decreased blood pressure or increased blood pressure and heart rate.