[Coronary artery spasm during coronary artery bypass surgery].

We report two cases of coronary artery spasm during coronary artery bypass surgery. As one of the complications during cardiac surgeries, coronary vasoconstriction occurs mainly after coming off cardiopulmonary bypass. The factors responsible for the spasm include high endogenous catecholamine levels due to inadequate anesthesia and hypothermia, exogenous catecholamines for circulatory support, various chemical mediators and combination of these factors. Coronary artery spasm was suspected strongly because of sudden ischemic change in electrocardiography and simultaneous aggravation of circulatory parameters, which improved immediately after direct injection of coronary vasodilators into vein graft. This method, popular in coronary angiography and catheterization, is effective for release of coronary-artery spasm observed particularly after cardiopulmonary bypass. Then mechanical circulatory assist is readily available to treat possible systemic side effect of the vasodilators.