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Assessment of aortocoronary bypass grafting using exercise ST segment/heart rate relation
Insights
The maximal ST/HR slope accurately identifies coronary heart disease severity and graft patency after bypass surgery. This exercise test reliably assesses myocardial blood supply restoration and detects graft issues.
Area of Science:
- Cardiology
- Exercise Physiology
- Diagnostic Testing
Background:
- Coronary heart disease (CHD) diagnosis and management are critical.
- Aortocoronary bypass surgery is a common intervention for severe CHD.
- Accurate assessment of surgical outcomes and disease progression is essential.
Purpose of the Study:
- To evaluate the maximal ST/HR slope as an index for assessing CHD severity.
- To determine the utility of the maximal ST/HR slope in patients undergoing aortocoronary bypass surgery.
- To assess the test's ability to detect graft patency and post-operative CHD progression.
Main Methods:
- Maximal ST/HR slope measurements were taken before and after aortocoronary bypass surgery.
- Coronary angiography was used to assess coronary artery disease and graft status.
- Data from 46 patients before surgery and 26 patients at six months post-surgery were analyzed.
Main Results:
- The maximal ST/HR slope showed no overlap between patients with no significant disease and those with single, double, or triple vessel disease.
- Post-surgery, the maximal ST/HR slope decreased, indicating improvement in myocardial blood supply.
- The test accurately identified the number of patent grafts and detected graft narrowing or occlusion.
Conclusions:
- The maximal ST/HR slope is a reliable non-invasive index for assessing CHD severity.
- This exercise test effectively indicates successful revascularization and detects post-operative graft complications.
- The maximal ST/HR slope aids in monitoring long-term outcomes after aortocoronary bypass surgery.
Abstract:
The maximal rate of progression of ST segment depression relative to increases in heart rate (maximal ST/HR slope) has recently been shown to be an accurate index of the presence and the severity of coronary heart disease in patients with angina. The value of this new exercise test was assessed in patients undergoing aortocoronary bypass. The maximal ST/HR slope and the results of coronary angiography were obtained in each of 46 patients before aortocoronary bypass surgery and in 26 of the 46 patients six months after the operation. At each stage of the investigation the maximal ST/HR slope detected without false results the absence and the number of significantly diseased vessels as shown by angiocardiography. As in previous findings the ranges of the maximal ST/HR slope showed no overlap between the four groups of patients: those with no significant disease and those with single, double, or triple vessel disease. In each of the 46 patients in whom the maximal ST/HR slope was determined before operation and three months afterwards the slope was lower after operation than before, indicating improvement. Follow up examinations showed that the maximal ST/HR slopes accurately detected the number of patent grafts used to bypass significantly diseased coronary arteries. Furthermore, the development of a significant narrowing or occlusion in any vein graft caused an increase in the maximal ST/HR slope which was equivalent to the value of single vessel disease. It is suggested that the maximal ST/HR slope may be used reliably in individual patients to indicate restoration of adequate blood supply to the myocardium after successfully aortorcoronary bypass surgery and the to detect in the period of six months after the operation the degree of severity of coronary heart disease whether it is caused by occlusion of the graft of significant disease of the coronary arteries.