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Coronary artery stenoses. Relationship between angiographic severity and impact on mean diastolic pressure gradient
Insights
Coronary angiography can suggest hemodynamic impact of coronary artery stenosis, but precise assumptions are not always possible. A good correlation was found between angiographic stenosis and pressure gradients, especially in the left anterior descending artery.
Area of Science:
- Cardiology
- Interventional Cardiology
- Vascular Surgery
Background:
- Coronary angiography is a key tool for assessing coronary artery stenosis anatomy.
- The correlation between angiographic appearance and hemodynamic significance remains an area of investigation.
Purpose of the Study:
- To investigate the relationship between the angiographic severity of coronary stenoses and the measured mean diastolic pressure gradient.
- To determine if hemodynamic impact can be reliably inferred from angiographic assessment.
Main Methods:
- Studied 29 coronary stenoses during coronary bypass surgery.
- Correlated angiographic percent stenosis with directly measured mean diastolic pressure gradients.
- Analyzed data based on lesion location (left anterior descending, right coronary, left circumflex arteries) and severity.
Main Results:
- A good correlation (r = 0.78, p = 0.001) was observed between mean diastolic gradient and percent stenosis.
- Correlation was stronger for lesions in the left anterior descending artery (r = 0.84, p = 0.001).
- Lesions >90% showed variable gradients, while <90% had more predictable gradients. Collaterals and history of myocardial infarction were associated with major gradients.
Conclusions:
- Angiographic assessment can provide some generalizations about the hemodynamic impact of coronary stenoses in defined situations.
- Precise functional assumptions based solely on angiographic appearance are not always possible.
- Direct pressure gradient measurement provides valuable hemodynamic information during surgery.
Abstract:
Coronary angiography provides important anatomic information about coronary artery stenoses. However, it is unclear whether specific assumptions about hemodynamic impact can be made from the angiogram. We therefore studied the relationship between angiographic severity of coronary stenoses and the mean diastolic pressure gradient measured directly at coronary bypass operation. We studied 29 stenoses selected because they were the only lesions in a given vessel, they were well seen in two angiographic views, and there was no change in clinical status of the patient between angiographic and surgical procedures. Fourteen stenoses were in the left anterior descending artery, nine were in the right coronary artery, and six were in the left circumflex artery. Correlation between mean diastolic gradient and percent stenosis was good (r = 0.78, p = 0.001) and especially so for lesions in the left anterior descending artery (r = 0.84, p = 0.001). Lesions over 90% had a wide range of gradients, while lesions less than 90% tended to have more predictable gradients. Collaterals invariably identified vessels with stenoses causing major pressure gradients. History of myocardial infarction was associated with major gradients in supplying vessels. Length of stenosis was not an important influence on gradient over a stenosis. We conclude that in some defined instances, generalizations about hemodynamic (and presumed functional) impact of stenoses can be made from the angiographic assessment, but precise assumptions are not possible.