Related Experiment Videos
Therapeutic approaches to postoperative ischemia. The Study of Perioperative Ischemia Research Group
1Department of Medicine, Veterans Affairs Medical Center, San Francisco, California 94121.
Insights
Early postoperative ischemia, detected by ambulatory electrocardiographic monitoring (AEM), significantly increases cardiac complications and mortality after non-cardiac surgery. Identifying high-risk patients warrants closer monitoring and preventative strategies.
Area of Science:
- Cardiology
- Anesthesiology
- Critical Care Medicine
Background:
- Postoperative cardiac complications are a major cause of morbidity and mortality.
- Previous research focused on preoperative patient status.
- Early postoperative cardiac events are strongly linked to adverse outcomes.
Purpose of the Study:
- To identify predictors of cardiac complications after non-cardiac surgery.
- To investigate the correlation between early postoperative ischemia and cardiac outcomes.
- To establish guidelines for interpreting ambulatory electrocardiographic monitoring (AEM) in specific patient groups.
Main Methods:
- Continuous ambulatory electrocardiographic monitoring (AEM) in the early postoperative period.
- Identification of predictors for postoperative ischemia.
- Analysis of cardiac death, myocardial infarction, and angina rates.
- Development of interpretation guidelines for AEM in patients undergoing cardiopulmonary bypass.
Main Results:
- Early postoperative ischemia significantly increases in-hospital cardiac death, myocardial infarction, or unstable angina (9-fold risk).
- Ischemia also elevates long-term risk (2-year) of cardiac death, myocardial infarction, or angina requiring revascularization (2-fold risk).
- Key predictors of ischemia include left ventricular hypertrophy, diabetes, hypertension, coronary artery disease, and digoxin use.
Conclusions:
- Patients at high risk for postoperative myocardial ischemia require intensified monitoring.
- Strategies to prevent or manage postoperative ischemia are warranted.
- Guidelines for AEM interpretation in cardiopulmonary bypass patients are proposed for future studies.
Abstract:
Previous attempts to identify predictors of cardiac complications, an important cause of postoperative morbidity and mortality following non-cardiac surgery, have focused mainly on the patient's preoperative state. Our research group, however, has found that adverse cardiac outcome correlates most highly with the appearance of at least 1 ischemic episode determined by continuous ambulatory electrocardiographic monitoring (AEM) in the early postoperative period. Such early postoperative ischemia conferred (1) a greater than 9-fold increased risk of experiencing in-hospital cardiac death, nonfatal myocardial infarction, or postoperative unstable angina, and (2) a greater than 2-fold increased long-term (2-year) risk of cardiac death, myocardial infarction, or angina requiring coronary angioplasty or coronary artery bypass grafting (CABG). Additionally, 5 predictors of such postoperative ischemia were identified: left ventricular hypertrophy, diabetes mellitus, hypertension, definite coronary artery disease, and preoperative digoxin use. These findings suggest that patients who are at high risk for postoperative myocardial ischemia warrant more intensive postoperative monitoring. Moreover, since such ischemia is potentially reversible, the testing of strategies designed to prevent or manage postoperative ischemia appears warranted and is discussed. Our group also has established the usefulness of AEM for identifying ischemic episodes in patients undergoing CABG. However, patients who require cardiopulmonary bypass present unique problems regarding the interpretation of AEM recordings. We describe guidelines for the interpretation of AEM results obtained under these conditions and suggest criteria based on the degree of interpretability for patient inclusion in future studies.