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What have we learned about coronary artery disease from high-frequency epicardial echocardiography?
R E Kerber1, D D McPherson, S J Sirna
1Department of Internal Medicine, University of Iowa College of Medicine, Iowa City.
Insights
High-frequency epicardial echocardiography accurately visualizes coronary artery atherosclerosis in real-time. This in-vivo method reveals diffuse disease missed by angiography and details lesion morphology and arterial remodeling.
Area of Science:
- Cardiovascular Imaging
- Medical Ultrasound
- Cardiac Surgery
Background:
- Coronary artery disease assessment traditionally relies on angiography.
- Angiography may underestimate the extent and severity of atherosclerosis.
- In-vivo visualization of coronary artery pathology is limited.
Purpose of the Study:
- To evaluate high-frequency epicardial echocardiography for visualizing and measuring coronary artery lumens and walls.
- To compare echocardiographic findings with angiographic and pathological data.
- To assess the accuracy of echocardiography in detecting diffuse atherosclerosis and lesion characteristics.
Main Methods:
- Utilized a 12 MHz epicardial echocardiographic probe on exposed coronary arteries during cardiac surgery.
- Obtained transverse cross-sectional views of the right coronary artery and left anterior descending coronary artery.
- Validated measurements against histological data from animal and human autopsy specimens.
Main Results:
- Echocardiography accurately measured coronary artery lumen and wall dimensions.
- Coronary arteries appearing normal or minimally diseased by angiography often showed severe, diffuse atherosclerosis.
- Identified diverse lesion shapes (oval, circular, complex) and locations (eccentric vs. concentric).
- Demonstrated arterial remodeling, with compensatory enlargement of total vessel area to maintain lumen patency.
Conclusions:
- High-frequency epicardial echocardiography provides accurate, real-time, in-vivo anatomical and functional evaluation of coronary atherosclerosis.
- This technique surpasses limitations of angiography by detecting diffuse disease.
- Offers insights into lesion morphology and compensatory remodeling, extending pathological study findings.
Abstract:
We have used a high frequency epicardial echocardiographic technique to visualize and measure coronary artery lumens and walls in patients undergoing cardiac surgery. A 12 MHz probe (Surgiscan, Biosound Corp.) is sterilized and placed on the exposed epicardial coronary arteries. Transverse cross-sectional views are obtained from the arteries on the anterior surface of the heart: the right coronary artery to the cardiac margin and the left anterior descending coronary artery to the cardiac apex. Numerous echocardiographic-angiographic-pathological correlations have been obtained from this work. We have validated the echocardiographic lumen and wall measurements by comparing the echo measurements to histological material from pressure-distended coronary arterial segments (from animals and fresh human autopsy specimens). We have shown by comparison with angiography that coronary arteries which appear normal or only minimally diseased by angiograms are often diffusely and severely atherosclerotic. We have also evaluated the shape of atherosclerotic lesions and demonstrated a wide range of lumen shapes (oval, circular, complex) and location within the residual coronary lumen (eccentric vs. concentric). Highly eccentric lesions are characterized by relative preservation of portions of the arterial wall, and this may preserve vasoreactivity of the atherosclerotic vessel. We have also demonstrated remodeling of atherosclerotic lesions: enlargement of the total arterial area (wall plus lumen) as a compensatory mechanism to preserve the arterial lumen in the face of encroaching atherosclerosis. High frequency epicardial echocardiography offers an accurate, real-time, in-vivo method for the anatomic and functional evaluation of coronary atherosclerosis. This dynamic, in-vivo technique supports and extends information previously obtainable only from pathologic studies.(ABSTRACT TRUNCATED AT 250 WORDS)