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The underlying coronary lesion in myocardial infarction: implications for coronary angiography
W C Little1, T R Downes, R J Applegate
1Department of Medicine, Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, North Carolina 27157-1045.
Insights
Sudden coronary artery occlusion causing myocardial infarction (MI) often occurs without significant stenosis on angiography. Coronary angiography may not accurately predict where future heart attacks will happen.
Area of Science:
- Cardiology
- Vascular Biology
- Medical Imaging
Background:
- Myocardial infarction (MI) typically results from acute thrombotic occlusion of a coronary artery.
- Atherosclerotic plaque rupture is the primary cause of this occlusion.
- Current diagnostic methods like coronary angiography may have limitations.
Purpose of the Study:
- To evaluate the accuracy of coronary angiography in predicting sites of future myocardial infarction.
- To investigate the relationship between angiographically visible stenosis and thrombotic occlusion in MI.
Main Methods:
- Review of serial angiographic studies in patients with myocardial infarction.
- Analysis of quantitative angiography data post-thrombolytic therapy.
Main Results:
- Most myocardial infarctions occur in arteries without angiographically significant stenoses (>50%).
- Coronary lesions underlying thrombi are often not severely stenotic.
- Angiographically apparent stenosis is not a prerequisite for thrombotic occlusion leading to MI.
Conclusions:
- Coronary angiography may underestimate the risk of atherosclerosis.
- The presence of significant stenosis on angiography does not reliably predict the site of future occlusive events.
- Newer imaging modalities may be needed for accurate risk stratification.
Abstract:
Myocardial infarction is usually caused by sudden thrombotic occlusion of a coronary artery at the site of a fissured atherosclerotic plaque. Recent evidence suggests that coronary angiography may be insensitive in detecting and quantitating atherosclerosis. Serial angiographic studies demonstrate that the majority of myocardial infarctions occur due to occlusion of arteries that previously did not contain angiographically significant (greater than 50%) stenoses. Similarly, quantitative angiography performed after thrombolytic therapy indicates that the coronary lesion underlying the clot is frequently not severely stenotic. Thus, an angiographically apparent stenosis is not necessary for the development of a thrombotic occlusion resulting in an MI. These observations suggest that coronary angiography does not accurately predict the site of a subsequent occlusion that will produce a myocardial infarction.