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A clinical method for detecting subendocardial ischemia after cardiopulmonary bypass
Insights
Subendocardial ischemia, a common cause of death after cardiopulmonary bypass, can now be detected early. A new method uses the endocardial viability ratio (EVR) to identify this risk before other vital signs change.
Area of Science:
- Cardiology
- Biomedical Engineering
- Critical Care Medicine
Background:
- Subendocardial ischemia and necrosis frequently cause mortality following cardiopulmonary bypass.
- This ischemia arises from an imbalance between the subendocardium's oxygen demand and its blood supply.
- Early detection of subendocardial ischemia is crucial for improving patient outcomes after cardiac surgery.
Purpose of the Study:
- To develop and validate a method for early detection of subendocardial ischemia in the postperfusion period.
- To introduce the endocardial viability ratio (EVR) as a sensitive indicator of myocardial oxygen supply-demand mismatch.
- To demonstrate the clinical utility of EVR measurement using commonly available equipment.
Main Methods:
- Development of an analogue computer system to calculate the endocardial viability ratio (EVR).
- Monitoring of EVR in patients during the postperfusion period after cardiopulmonary bypass.
- Comparison of EVR changes with traditional hemodynamic parameters like systemic and central venous pressure.
Main Results:
- The endocardial viability ratio (EVR) was found to decrease prior to significant changes in systemic or central venous pressure.
- This early decrease in EVR effectively indicates the onset of subendocardial ischemia.
- The method proved reliable and utilized equipment standard in coronary care units.
Conclusions:
- The endocardial viability ratio (EVR) is a valuable and sensitive marker for the early detection of subendocardial ischemia after cardiopulmonary bypass.
- This non-invasive technique allows for timely intervention, potentially reducing mortality associated with post-bypass ischemia.
- The accessibility of the required equipment facilitates widespread clinical application of EVR monitoring.
Abstract:
Subendocardial ischemia with consequent subendocardial necrosis is a frequent cause of death after cardiopulmonary bypass. The problem is caused by an inequity in the oxygen requirements of the subendocardium and the available blood supply. We have developed a means of detecting ischemia early in the postperfusion period. Using an analogue computer, we determine the endocardial viability ratio (EVR). This value may decrease before either systemic or central venous pressure changes. Thus the ratio can reflect early the danger of subendocardial ischemia. Another advantage is that equipment now common in coronary care units can be used to determine the EVR.