Implications of triiodothyronine administration before cardiac and noncardiac operations

Before the potential for the use of a revolutionary new strategy such as administration of triiodothyronine before or during cardiac or noncardiac operations can be evaluated, previous aspects of anesthetic management of patients with coronary artery disease must be considered. In the late 1970s, efforts were made to minimize myocardial oxygen consumption to improve postsurgical mortality. These consisted of attempts to limit myocardial oxygen demand (eg, keeping heart rate low, preventing hypertension, maintaining coronary perfusion pressure). Subsequently, clinical findings indicated that nonhemodynamic ischemia was common during anesthesia. A second era of anesthetic management of patients with coronary disease was aimed at preventing reduced myocardial oxygen supply because coronary vasomotion was found to be related to myocardial ischemia. Because myocardial ischemia is still associated with apparently well-managed anesthesia and operation, investigators are now looking for new avenues to prevent morbid perioperative ischemic events. Investigational agents including intravenous triiodothyronine may serve as cardioprotective agents in the future if they are proven to prevent ischemia or enhance efficiency of contraction without tissue injury in ischemic or postischemic myocardium.