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Silent myocardial ischemia during coronary angioplasty
M Dellborg1, H Emanuelsson, K Swedberg
1Department of Medicine, Ostra Hospital, University of Göteborg, Sweden.
Insights
Silent myocardial ischemia, often without chest pain during cardiac events, is linked to diabetes and collateral circulation. This suggests a less severe ischemic event may be protected by collaterals.
Area of Science:
- Cardiology
- Ischemic Heart Disease
Background:
- Silent myocardial ischemia is a significant indicator in coronary artery disease patients, predicting future cardiac events.
- Some patients with angina pectoris experience myocardial ischemia without chest pain during provoked events.
Purpose of the Study:
- To investigate clinical, angiographic, and electrocardiographic differences between patients with and without chest pain during provoked myocardial ischemia.
- To explore the characteristics of silent ischemia during coronary angioplasty.
Main Methods:
- 114 patients with angina pectoris were monitored using dynamic, computerized vectorcardiography during coronary angioplasty.
- Comparison of patient characteristics and ischemic responses between those with and without chest pain during balloon inflation.
Main Results:
- 33 out of 114 patients experienced silent ischemia during angioplasty.
- Silent ischemia was associated with a history of diabetes, presence of collateral circulation, less severe prior angina, and fewer ST segment changes.
- No significant differences were found in reasons for exercise test termination or anti-ischemic drug regimens.
Conclusions:
- Silent myocardial ischemia during coronary angioplasty may be associated with a less severe ischemic burden.
- The presence of collateral circulation might offer a protective effect, mitigating ischemia and pain perception.
Abstract:
Silent myocardial ischemia is a marker in patients with coronary artery disease identifying those at high risk for subsequent cardiac events. During provoked myocardial ischemia some patients with angina pectoris do not develop chest pain. Are there clinical, angiographic or electrocardiographic differences between patients with chest pain as compared with patients without chest pain during provoked myocardial ischemia? Coronary angioplasty is a well-established method for the treatment of coronary stenosis, but it is also an interesting model for the study of myocardial ischemia as a result of coronary occlusion. We monitored 114 patients with angina pectoris during coronary angioplasty with dynamic, computerized vectorcardiography. During inflation of the balloon 33 of 114 patients had silent ischemia. Patients with silent myocardial ischemia had similar reasons for terminating the preangioplasty exercise test and where on similar anti-ischemic drug regimes. Silent myocardial ischemia was significantly associated with a history of diabetes, presence of collaterals, a history of less severe previous angina and less ST segment changes during angioplasty as compared with patients with painful ischemia. It is suggested that during coronary angioplasty silent ischemia may be caused by a less severe degree of ischemia, possibly as a result of the protective effect of collaterals.