Healthy arteries are smooth and flexible. In a person with CAD, the arteries are narrowed with a buildup of plaque. Blood cannot flow as easily through diseased arteries. When blood flow is restricted to the heart, the heart muscle cannot get enough oxygen and pain or discomfort occurs. This pain or discomfort, which can be felt in the chest, arms or lower jaw, is called angina, the AHA says. Sometimes, the blood flow in the narrowed arteries is blocked completely by a clot. If this happens, the heart muscle cannot get oxygen and the person suffers a heart attack. The area of the heart affected by the blockage dies and becomes scar tissue.

An electrocardiogram (ECG) shows the heart's electrical activity. An ECG is used to find out if a heart attack has occurred. It also shows which parts of the heart muscle may not be getting enough blood. The treadmill stress test also helps determine how blood is flowing through your arteries. It shows how your heart and body respond electrically during exercise. A radioactive dye may be injected into your bloodstream so that an X-ray camera can see the blood flow during the test. The main tool for diagnosing coronary artery disease, however, is cardiac catheterization and angiography. A dye is injected through a catheter placed in the coronary arteries and an X-ray is taken of the outline of the artery. This test can pinpoint where the arteries are narrowed or even blocked. In the future, however, CAD may be diagnosed using high-resolution magnetic resonance imaging (MRI).

It is also called balloon angioplasty. The balloon is placed in the artery by means of a fine tube called a catheter. The catheter usually is inserted into a blood vessel in an elbow or groin and travels to the heart. Once the end of the catheter reaches the blockage, the balloon is inflated and deflated several times to push the plaque against the artery wall and open and stretch the artery, the NHLBI says. This stretching helps improve the flow of blood through the artery. A variation on this procedure uses a laser instead of a balloon. The laser vaporizes plaque in an artery. Laser angioplasty has been used alone and along with balloon angioplasty. Angioplasty also can be used to open an artery in an arm, leg or neck. There are several benefits to angioplasty. It opens up an artery without the risks associated with major surgery. It retains the original artery instead of replacing it, as is done in bypass surgery. And it does not require general anesthesia.

The stent helps keep the artery open after the balloon is removed. The stent stays in place permanently. A stent is used in 70 to 90 percent of angioplasty procedures, the AHA says.

Arteries and other blood vessels that become narrow or blocked again can be reopened with a second angioplasty. Arteries with stents also can become blocked again in time. This occurs much less frequently than before stents were used. The doctor may choose to recommend a coronary artery bypass graft, the NHLBI says.

All these risk factors are very important to change. The most important one, however, is smoking. The AHA says that people who continue to smoke after having angioplasty have a much worse quality of life than those who quit or who are nonsmokers. Those who continue to smoke are at higher long-term risk for heart attack and death.