Perioperative ischemia results from an imbalance of oxygen supply and demand of the myocardium during perioperative stress, rupture of a vulnerable plaque with subsequent thrombosis of a coronary artery, endothelial dysfunction, or some combination of all of these.
The history and physical examination, along with limited indicated tests, are often adequate to determine the general perioperative risk of a patient.
Preoperative cardiac testing is usually not needed in patients who have good functional status or are undergoing low-risk procedures. Further testing is unlikely to change management, and these patients may proceed directly to surgery.
Many interventions, such as control of diabetes, hypertension, stable coronary artery disease, congestive heart failure, and endothelial function, can be well within the scope of an anesthesiologist's skill set. If anesthesiologists wish to consider themselves perioperative clinicians, they must be active in these well-established aspects of medicine.
The attending anesthesiologist of a specific patient, not a consultant, is in the best position to balance the risks and determine the best anesthesia techniques for that case. Other clinicians and consultants are often needed to ensure optimization, although increasingly, the anesthesia team can do at least some of this.
Preoperative evaluation continues to change. In the distant past, the attending anesthesiologist would interview the hospitalized patient and family a day or two before surgery. All resources of the medical systems were mobilized to ensure that all aspects of the patient's health were assessed and treated. Surgery was delayed until any cardiac condition was fully addressed.
Practice changed; it then became common for any potentially complex patient to see a consultant to get “clearance” so surgery could proceed with some nebulous guarantee of acceptable risk, or surgery would be cancelled until such clearance could be provided.
Current practice includes surgery and anesthesia techniques that are numerous and changing. Anesthesiologists are able, if needed, to shepherd high-risk patients through high-risk surgery. Consideration is given to striking a balance between risks at either end of a spectrum, weighing the risk of postponing surgery versus proceeding. At one end, postponing surgery for investigations may be higher than the risk of proceeding. At the other end of the spectrum, some surgical procedures are unlikely to cause more stress than the activities of daily living. In essence, the paradigm of preoperative assessment is shifting from predicting risk to actively managing risk.1 The issue is less whether to cancel surgery and more whether indicated cardiac tests and management need to be done preoperatively under the supervision of the perioperative physician or postoperatively in a more elective fashion by primary care clinicians.
As medical therapy of cardiovascular disease improves, routine care is sometimes as effective as interventional therapy in reducing cardiac morbidity and mortality.2 This chapter reviews current understanding of the physiology of perioperative ischemia, followed by examination of how an individual patient's perioperative risk can be assessed. More importantly, it then discusses when and how more detailed risk ...