AbstractNew technical challenges involving the delivery of cardioplegia during the course of coronary artery bypass operation continue to be presented to the surgeon. Functioning saphenous grafts at reoperation that are at risk for distal embolization, are managed by altering the standard cardioplegia delivery techniques. Management of patent internal mammary artery (IMA) grafts depends upon the status of the native circulation and coronary collateral. The reoperation may be performed with a fibrillating heart, standard cardioplegia with a clamped mammary graft, or cardioplegia delivered during simultaneous circulatory arrest. Myocardial temperature measurements, during the course of more complex operations, are useful in choosing the appropriate technique for myocardial protection.