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How and why does the heart pump blood to itself?

Angioplasty, Bypass Surgery and Stents: Helping Hungry Hearts
Pictured is a digital representation of what your heart might look like after bypass surgery. This surgery is bypassing a coronary artery.
Pictured is a digital representation of what your heart might look like after bypass surgery. This surgery is bypassing a coronary artery.
3D Clinic/Getty Images

Your heart receives its blood from the coronary arteries. These arteries begin life big, soft and smooth inside. As we grow older, we damage those once-supple arteries with stress, fast food, not enough exercise and age. Over decades, they collect plaque (or fatty deposits) along their inner walls, causing them to harden and narrow. This condition is known as atherosclerosis. Unchecked, atherosclerosis may worsen and become coronary artery disease (also known as coronary heart disease). Doctors tend to shorten it to just CAD or CHD.

As CAD advances, a number of things can happen. For example, if a portion of your heart muscle is receiving some -- but not enough -- oxygen due to partially blocked arteries, it won't be permanently damaged, but the muscle won't like the situation one bit. It files a formal complaint with you in the form of chest pain called angina. Stable angina is the lesser of two evils; it's predictable and reversible. Unstable angina, however, could signal an unstable plaque that could cause a heart attack.

You may not feel this chest pain when you're relaxing because your heart doesn't require much blood when you're sunning yourself by the pool. If you start swimming laps, however, it needs more than your narrowed arteries can deliver, and this hurts.

Blockages lower the amount of oxygen getting to the heart muscle. If one of these obstacles breaks open, a clot forms at the site of the rupture in the plaque. This little clot can totally block the artery within minutes. When heart tissue is cut off from oxygen, it quickly begins to die. This, typically, is your heart attack (or myocardial infarction).

If your coronary arteries become dangerously blocked, doctors may discuss one of the following procedures with you.

Angioplasty: This procedure uses a tiny balloon to open a clogged artery. A balloon catheter is inserted into an incision near the groin and threaded up through an artery into the heart. Then doctors inject dye and search for blockages. Once found, they put the catheter through the blockage narrowing and inflate the balloon. This procedure won't stop the arteries from hardening again, but it will lessen the pain and other symptoms of CAD by increasing the blood flow.

Stenting: Sometimes, in addition to or instead of angioplasty, a metal or plastic tube called a stent may be inserted into a blocked artery to prop it open. Doctors may perform angioplasty and stenting on a patient before, after or during a heart attack. Some cardiologists prefer just stenting without angioplasty. The drawback of this procedure is that stents can clog, just like your arteries.

Coronary artery bypass graft (CABG): During a "traditional" CABG, your heart is stopped, and you're placed on artificial respiration. A vein or artery that won't be missed too much is taken from somewhere else, possibly your arm or leg. Surgeons attach one end of the graft to the aorta and the other end to the troubled artery on the far side of the blockage. This detour enables blood to bypass the blockage and flow unobstructed from the aorta to the heart. Most grafts continue working properly for 10 or 15 years [source: Medline Plus]. When you hear the terms double-, triple- or even quadruple-bypass surgery, it refers to the number of arteries receiving bypass grafts.

The main thing your heart needs is the same thing it distributes to the rest of your body: oxygen-rich blood. By living a heart-healthy lifestyle, your heart should get the natural resources it needs to do what it does best, without the help of balloons, tubes or relocated veins or arteries. See the next page for lots more information about the heart.