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Atheroma morphology and distribution in proximal left anterior descending coronary artery: in vivo observations
B J Kimura1, R J Russo, V Bhargava
1Division of Cardiovascular Medicine, University of California-San Diego Medical Center, California 92103, USA.
Insights
Atheromas in the proximal left anterior descending artery are eccentric, sparing the flow divider. These in vivo findings support fluid dynamics
Area of Science:
- Cardiovascular Research
- Medical Imaging
- Biomedical Engineering
Background:
- Atherosclerosis in the proximal left anterior descending artery is linked to disturbed shear forces.
- In vivo data on the shape and location of advanced atheromas in this region are lacking.
Purpose of the Study:
- To investigate the in vivo morphology, specifically the shape and position, of atheroma in the proximal left anterior descending coronary artery.
Main Methods:
- Analysis of 42 high-quality intravascular ultrasound images from patients with proximal left anterior descending artery atherosclerosis.
- Measurement of lesion percent area stenosis, intimal-medial thickness, and plaque angle relative to the flow divider.
Main Results:
- Atheromas demonstrated significant eccentricity, with maximal wall thickness (1.42 mm) differing from minimal thickness (0.17 mm).
- Maximal plaque thickness consistently spared the flow divider region (100% of cases) and was located at a mean angle of 193 degrees.
- Eccentric morphology persisted across a wide range of area stenoses (24%–80%).
Conclusions:
- Proximal left anterior descending artery atheromas are characteristically located opposite the circumflex takeoff, spare the flow divider, and maintain eccentricity.
- These in vivo findings support the role of fluid dynamics in atherogenesis.
- The observed morphology has implications for the success of catheter-based interventions at this site.
Objectives:
This study sought to examine, in vivo, the shape and position of atheroma in the proximal left anterior descending coronary artery.
Background:
The prevalence, shape and location of atheromas involving the proximal left anterior descending artery have implications regarding the role of disturbed shear forces in the genesis of atherosclerosis. However, no data are available regarding in vivo findings or advanced disease.
Methods:
Forty-two consecutive high quality intravascular ultrasound images were examined from patients with atherosclerotic disease in the proximal left anterior descending artery just distal to the left main bifurcation. Lesion percent area stenosis and maximal, minimal and flow divider intimal-medial thickness were measured at the region immediately after the circumflex takeoff. The angle formed by the midpoint of the flow divider, the human center of gravity and the maximal plaque thickness were determined.
Results:
Eccentricity of vessel wall atheroma was observed such that the maximal wall thickness (1.42 +/- 0.50 mm [mean +/- SD]) differed significantly from minimal wall thickness (0.17 +/- 0.098 mm). Further, the region of vessel wall manifesting maximal thickness was greater than the flow divider thickness (0.26 +/- 0.16 mm). Maximal plaque thickness spared the region of the flow divider in 100% of cases and was positioned at a mean angle of 193 +/- 49 degrees from the center of the flow divider. Eccentric morphology was maintained across the 24% to 80% range of area stenosis.
Conclusions:
Atheromas in the very proximal left anterior descending artery are located opposite the circumflex takeoff, spare the flow divider and maintain eccentricity across a wide range of vessel stenoses. These in vivo morphologic data support the potential role of fluid dynamic mechanical factors in atherogenesis and have implications regarding the success of catheter-based interventional procedures at the site.