The management of perioperative ischemia

Perioperative myocardial ischemia is insidious, difficult to diagnose, and must be treated immediately otherwise the ensuing myocardial infarction will result in a torrid perioperative course, higher early mortality, and poor cardiac function and reduced long-term survival. Myocardial ischemia may occur during the anesthetic and prebypass phase while handling the heart—especially in off-pump coronary surgery. It may become an evident post–cardiopulmonary bypass or in the intensive care unit. There are many potential causes that include hypotension, cardiac compression and displacement, technical graft and anastomotic problems, coronary artery, and graft spasm. It can also occur in non–coronary artery bypass graft surgery (CABG) cardiac surgery. Awareness, prompt diagnosis, and immediate correction are essential. Bypass graft flows and regional wall motion evaluation should always be performed and be satisfactory before finishing surgery. In the postoperative intensive care setting, myocardial ischemia should be managed by taking the patient promptly for cardiac catheterization for an objective assessment of the coronary arteries, grafts, and aorta to guide “rescue” interventions—most of which can be expeditiously accomplished there. Only a small minority will require return to the operating room. This chapter will explore perioperative myocardial ischemia in detail, especially in CABG, from a practical, surgical perspective.