Using high resolution B–mode ultrasound it was possible to identify and categorize plaques into the following two categories:
- Echolucent plaques have a lipid and macrophage rich core with a thin fibrous cap. They do not cause a narrowing of the arterial wall (stenosis) due to compensatory elasticity, and are therefore not associated with symptoms of stable angina or unstable angina. However, they are defined as vulnerable plaques prone to rupture. Several studies have shown that echolucent carotid plaques are predictors of acute coronary events.
Upon rupture, atheroma material spills into the blood causing the formation of clots that are either dissolved or are passed downstream to the capillaries causing slow but steady damage. Since echolucent plaques in the arteries exist throughout the body, rupture can cause damage to the eyes, toes, fingers, brain, kidneys, lungs, et cetera. In more severe cases the results are heart attacks and strokes.
- Echogenic plaques have a high tissue and calcium core with a thick fibrous cap. They are associated with the hardening and narrowing of the arterial wall (stenosis), and are easily detected in clinical studies by standard angiograms. Advance stages can restrict the flow of blood, however, the plaque tends to be stable.
The main results of the study are “that oxidized LDL is independently associated with echolucent carotid plaques after taking into effect systolic blood pressure” and is predictive of acute coronary events and corresponding damage to key body organs.
Considerable work needs to be done, but the malondialdehyde (MDA)-modified LDL assay may play a key role in the identification and treatment of unstable plaque. Applications would be for patients entering the emergency room with chest pains and the determination of the stages of coronary artery disease and its affect throughout the body. Since atherosclerosis is a body-wide process, plaque rupture and the corresponding formation of blood clots may cause damage to the kidneys, lungs, brain, eyes, etc.
As a side note, it is interesting that “several systemic inflammatory markers such as hsCRP have been shown to predict future cardiovascular events, but whether they are associated with early atherosclerosis is uncertain. Chapman et al. showed that the monocyte count, but not hsCRP or interleukin-6, was an independent marker for subclinical carotid atherosclerosis. Museari et al. found no association between hsCRP and echolucent carotid plaques. This is in line with our findings showing no significant association between hsCRP and echolucent plaques in the carotid artery”