Sunday, May 04, 2008

Higher Total Cholesterol May Increase The Risk of Plaque Rupture!

We always accuse LDL (so-called bad cholesterol) as the culprit that causes heart attack, stroke, high blood pressure, etc. Not so much attention is given to someone with higher than average total cholesterol level, provided the HDL (good cholesterol) level is at healthy level.

However, the findings of a new study conducted by a group of investigators from Johns Hopkins School of Medicine, Baltimore may change such perspective. Published in February 2008 in the medical journal Stroke, the report revealed that the total blood levels of cholesterol in individuals without symptoms but have thickened walls of the carotid arteries are strongly associated with the presence of a lipid (or fat-based) core within plaque, which can cause the arteries to rupture.

The carotid arteries are two major arteries located on each side of the neck that provide blood and oxygen to the brain.

Made up of fatty dead tissue deposits, a lipid core within an atherosclerotic plaque puts the plaque at risk for causing an adverse clinical event, such as a stroke if the plaque is in the carotid artery or a heart attack if the plaque is in the coronary artery.

By taking part in a study of atherosclerosis (also referred to as hardening of the arteries), the participants were examined by ultrasound to ensure they are free from cardiovascular disease and those with the thickest carotid artery walls were selected.

The researchers used MRI and analysis software to assess the composition of 214 plaques with a thickness of at least 1.5 millimeter and found a lipid core in 151 (71 percent) of these plaques.

Compared with patients with the lowest levels of total blood cholesterol, those with medium levels had a 2.8-fold increased risk of having a lipid core, after adjusting the possible effects of age, sex, high blood pressure and diabetes. Those with the highest cholesterol levels had a 4.6-fold increased risk of having a plaque with a lipid core. None of the cardiovascular risk factors other than high serum cholesterol was associated with having a lipid core.

The researchers concluded that a person’s total cholesterol level is the most important risk factor for developing the dangerous feature of plaque mentioned above. This indeed supports the claim that by lowering a person’s cholesterol level and hence the risk of the formation of lipid core might reduce his or her risk of the possible clinical events.

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