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. 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. This can severely affect how the heart functions. Sometimes the damage can be so great that it stops the heart. This is known as cardiac arrest.

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. But the main tool for diagnosing coronary artery disease 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. Your doctor may then use a procedure such as angioplasty or coronary artery bypass grafting to help open up these blockages. The procedures may be done during catheterization. CAD may be diagnosed using high-resolution MRI and cardiac CT, which uses an X-ray machine to take detailed pictures of the heart.

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 a wrist or the groin and travels to the heart. Once the end of the catheter reaches the blockage, the doctor inflates and deflates the balloon several times to push the plaque against the artery wall and open and stretch the artery. This stretching helps improve the flow of blood through the artery. There are several benefits to angioplasty. It opens up an artery without the risks of major surgery, and it does not need general anesthesia. A stent may be placed to hold the artery open after a balloon has expanded the blockage.

The stent is a small metal coil or mesh tube that is placed in a narrowed artery. It helps keep the artery open after the balloon is removed. The stent stays in place permanently. A stent is used in many angioplasty procedures.

Arteries and other blood vessels that become narrow or blocked again can be reopened with a second angioplasty. This occurs much less often now that stents are commonly used. But arteries with stents can still sometimes become blocked again over time. Some stents are coated and slowly release medicine over a period of time. This reduces the amount of scar tissue that forms inside the artery. It helps prevent restenosis. Your doctor will give you medicine to prevent blood clots from forming on the new stent. You will continue to take this medicine until the stent and artery have healed. Your healthcare team will tell you how long you should take this medicine.

All of these risk factors are very important to change. The American Heart Association 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.