Dynamic predictors of perioperative risk. Study of Perioperative Ischemia (SPI) Research Group

Reduction in perioperative cardiac morbidity requires new approaches to the management of cardiac surgery patients or high-risk noncardiac surgery patients. Studies that have addressed the perioperative dynamic predictors of risk suggest a number of conclusions. Intraoperative hypotension and tachycardia appear to be risk factors for perioperative cardiac morbidity, whereas the role of hypertension remains controversial. It has recently been shown that ischemia occurring prior to bypass doubles or triples the risk of subsequent myocardial infarction. Electrocardiographic determination of ST segment depression is used as an indicator of ischemia, as are changes in ventricular filling pressure. Although increases in left ventricular end-diastolic pressure have proved to be reliable indicators of ischemia, changes in pulmonary capillary wedge pressure or pulmonary artery diastolic pressure have not. Perioperative segmental wall-motion or wall-thickening abnormalities appear to provide the most sensitive clinical measure of ischemia. Preliminary data also suggest that transesophageal echocardiographic wall-motion abnormalities may predict adverse outcome following cardiac surgery. Recent information regarding dynamic predictors of perioperative cardiac morbidity stresses the importance of the postoperative period.