16.2

Coronary Artery Diseases

Coronary arteries of a physically fit person are normally smooth and elastic. The

endothelium lining protects the walls enabling effective working of the arteries and

thus permitting a free flow of blood through them. Coronary artery disease may

begin at a very young age with the appearance of streaks of fat in the walls of the

blood vessel which, in turn, may result in buildup of fat with passage of time

resulting in minor damage to the blood vessel walls. Other constituents of blood

streams, viz., proteins, calcium, inflammatory cells, and other cellular waste

products, stick to the vessel wall and combine with the fat to form a plaque as

shown in Fig. 16.1. These plaques could differ in size and softness and could be

covered with a hard fibrous cap which may eventually crack or tear with time.

Though excessive plaque ultimately restricts the blood flow in arteries, it is often

hard to diagnose early. Platelets migrate to these areas and build up blood clots

around the plaque. In addition, the endothelium too may get irritated and conse-

quently stop functioning and thus coercing artery to squeeze inconsistently resulting

in further narrowing down of the artery. At times these clots may break apart

resuming the blood flow in the region, and at other times the blood clot may

completely block the supply of blood to the heart muscle, initiating a severe disorder

known as acute coronary syndrome. Thus, coronary artery disease leads to athero-

sclerosis—narrowing of coronary arteries by plaque which is depicted in Fig. 16.2.

Arteries get clogged by formation of these plaques and hence get damaged by the

Plaque Build-Up

plaque build-up

platelets

clot

lining of coronary

artery

fatty matter starts

to build up

coronary artery wall

Fig. 16.1 Plaque buildup by combination of fat with constituents of blood stream

Normal Artery

Narrowing of Artery

Lipid deposit of

plaque

Fig. 16.2 Lipid deposit of

plaque in the artery

16

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