The body’s arterial system carries oxygenated blood from the heart to the rest of the body. The aorta, the largest artery in the body, arches upward from the top of the heart and then descends through the middle of the torso. Smaller arteries branch off from the aorta and distribute blood to muscles, organs and other body tissues.

THE IMPACT OF ATHEROSCLEROSIS

As people age, the normal flow of blood through the arteries can be affected by the buildup of plaque inside the arteries. The plaque is made up of cholesterol or lipids, calcium and fibrous tissue. This buildup of atherosclerotic plaque is more likely to occur at sites where arteries divide and give off into branches. These areas, called bifurcations, are subject to greater turbulence in the flow of the blood.

Over time, plaques continue to grow on arterial walls as cholesterol circulates in the blood, and as the plaques enlarge the arteries become narrow and stiffened. This process is called atherosclerosis, commonly known as ‘hardening of the arteries’ because the plaque buildup thickens the walls of the arteries, narrowing the space through which blood flows. When this narrowing occurs in an artery, the circulation of blood through the area of the body that gets its blood from the artery is reduced. Poor circulation in turn can cause ischemia, or a decrease in blood flow that causes insufficient oxygen levels in body tissues.

RESTORING THE FLOW OF BLOOD

Angioplasty is a procedure during which doctors inflate a small balloon inside a blood vessel to eliminate or reduce areas of narrowing inside the blood vessel. The goal of angioplasty is revascularization, or the restoration of an adequate flow of blood in a part of the body. Angioplasty accomplishes this restoration of blood flow by actually enlarging from within a blood vessel the area through which blood may flow.

Arteries have three layers: a thin, smooth inner layer, a muscular, elastic middle layer and an external layer of connective tissue. Inflating an angioplasty balloon inside an artery affected by atherosclerotic buildup causes a kind of controlled, helpful injury to the artery. As doctors inflate the balloon, the smooth inner layer, which typically covers any plaque buildup inside the artery, stretches and tears as the balloon inflates. When the balloon continues to inflate, plaque deposits are compressed, and any fluid in the plaque deposit is squeezed out. The plaque may break, or fracture, and the muscular middle layer of the artery begins to stretch. Usually, the external layer of an artery is not stretched during angioplasty.

The compression and break-up of plaque deposits enlarges the area inside an artery through which blood may flow. Also, when the inner layer of an artery is stretched and torn, the body’s natural healing process is triggered, which also helps the process of breaking down and reducing the size of the plaque and smoothing the internal surface of the vessel.