Clinical Nutrition

Lesson 26: Cardio Vascular Disease- Risk factors, Lipo and Apo proteins

Atherosclerosis

Atherosclerosis causes the major pathologic process in coronary heart disease. The characteristic lesions are raised, fibrous plaques on the innermost surface of the blood vessel, the intima. The plaque contains fatty material like lipo proteins, dead cells, crystals of cholesterol etc. as this plaque thickens, it narrows the vessel lumen. Because it projects into the blood vessel, it irritates the blood flowing in the vessel and causes blood clots to be formed. Eventually this ‘embolus’ may cut off the blood flow in the involved artery. Thus the area serviced by the artery is deprived of vital oxygen and nutrients and the cells die. The dead cells/tissue is called an infarct. If the artery involved is one supplying the cardiac muscle, it leads to myocardial infarction. If the artery supplies blood to the brain it leads to cerebro vascular accident or stroke. Thus in coronary heart disease the focus is on the fatty plaque or atheromas. The atheromas may be caused by damage to the intima of the blood vessel leading to formation of blood clots. The damage may be due to high blood pressure or from carbonmonoxide in the blood as a result of cigarette smoking. Serum lipids, especially serum cholesterol in high levels could also lead to atheroma formation and heart disease. In fact high serum lipids could be the main factor leading to plaque formation.

Atheriosclerosis: Thickening of arterial walls with loss of elasticity.
Intima : innermost layer of a blood vessel.
Ischemia: Deficiency of blood to a body part resulting from constriction or obstruction of a blood vessel.
Infarct: Death of tissue due to lack of blood flow.
Coronary arteries: Arteries that carry blood to the heart.

There are five stages to atherosclerosis Phase I: Asymptomatic phase which consists of fatty streaks which are non-obstructive lipid filled cells Phase II: Consists of plaque with high lipid content and prone to rupture with main lipid being LDL Phase III: Acute complicated phase with rupture of non-occlusive thrombus Phase IV: Acute complicated lesions with occlusive thrombuswhich are associated with angina/myocardial infarction. Phase V: Fibrotic or occlusive lesions.

Angina pectoris: Chest discomfort if often reported by most patients especially those which are chronic cases of dyslipidemia and/or hypertension.