Ischemic heart disease

What is Ischemic heart disease/Coronary artery disease?

Coronary artery disease is the most common type of heart disease. Also known as coronary heart disease, it affects about 13 million Americans. The cause of coronary artery disease is atherosclerosis — the gradual buildup of plaques in blood vessels that feed your heart (your coronary arteries).
Over time, these plaques — deposits of fat, cholesterol, calcium and other cellular sludge from your blood — can narrow your coronary arteries, so less blood flows to your heart muscle. Diminished blood flow to your heart can cause chest pain (angina). A sudden, complete blockage can lead to a heart attack. Each year, more than 500,000 Americans die of complications of coronary artery disease.
The problem is that many people who have this form of heart disease aren’t aware they have it. Coronary artery disease develops slowly and silently over decades. It can go virtually unnoticed until it produces a heart attack.
You can prevent or slow coronary artery disease by taking steps to improve the health of your heart and blood vessels. Drugs and surgical techniques can repair narrowed coronary arteries, but the best long-term solution is to make lifestyle choices that can help control the risk factors for coronary artery disease.

Signs and symptoms of Ischemic heart disease

Coronary artery disease varies both in signs and symptoms and in severity. It may produce no symptoms, or it can produce chest pain of varying degrees as well as shortness of breath. It may also result in a heart attack.
Like any muscle, your heart needs a steady supply of oxygen-rich and nutrient-rich blood to function. Your coronary arteries encircle your heart like a crown and branch off into your heart muscle, supplying it with blood.
If your coronary arteries become narrowed, they can’t supply enough oxygenated blood to your heart when it’s beating hard, as when you exert yourself. An insufficient blood supply to the heart or other organs is called ischemia. When it affects the heart, it is known as cardiac ischemia. Cardiac ischemia can result in:

• No symptoms. This is referred to as silent ischemia. Blood supply to your heart may be restricted due to coronary artery disease, but you don’t feel any adverse effects.
• Chest pain. If your coronary arteries can’t supply enough blood to meet the oxygen demands of your heart, the result may be chest pain called angina. It’s often described as a pressure or tightness in the chest — as if someone were standing on your chest. Angina is usually brought on by physical or emotional stress. The pain typically goes away within minutes after stopping the stressful activity.
• Shortness of breath. Some people may not be aware they have coronary artery disease until they develop symptoms of heart failure — extreme fatigue with exertion, shortness of breath and swelling in their feet and ankles. Heart failure occurs when your heart becomes so weakened from insufficient blood supply or from a heart attack that it can’t pump enough blood to meet your body’s needs.
• Heart attack. A heart attack results when an artery to your heart muscle becomes completely blocked and the part of your heart muscle fed by that artery dies. This is usually caused by a blood clot or other blockage in an already narrowed coronary artery. Pain from a heart attack is often described as crushing and may feel similar to angina, but it lasts longer.

Causes of Ischemic heart disease

Arteries are blood vessels that carry oxygen-rich blood away from your heart, to all of the tissues of your body — including your heart itself.
Healthy arteries — including healthy coronary arteries — are clean, smooth and slick. The artery walls are flexible and can expand to let more blood through when necessary. Artery disease is thought to begin with an injury to the lining of the walls of arteries. This injury makes them susceptible to atherosclerosis.
Atherosclerosis is the slow, progressive buildup of deposits called plaques on the inner walls of your arteries. Plaques are deposits of fat, cholesterol, calcium and other cellular material from your blood.
These plaques both narrow and harden arteries. Plaques alone can significantly block your coronary arteries and arteries throughout your body. They can also become fragile and rupture, forming blood clots that can block blood flow to your heart or elsewhere in your body.
Atherosclerosis is a complex disease that starts in childhood and usually progresses as you age. In some people, atherosclerosis progresses rapidly, especially those with risk factors such as smoking, high blood pressure, diabetes and high cholesterol. Obesity and physical inactivity are other factors that can contribute to this disease.
A high blood level of low-density lipoprotein (LDL) cholesterol — so-called “bad” cholesterol — can lead to atherosclerosis. High blood cholesterol can be an inherited problem, but it’s also typically a byproduct of poor health habits — such as eating a high-fat, high-cholesterol diet, which is common in Western societies. When the level of LDL cholesterol in your blood is high, there’s a greater chance that it will be deposited onto your artery walls. Higher levels of the “good” cholesterol, high-density lipoprotein (HDL), seem to protect against heart disease.
Some research suggests that a bacterium, such as Chlamydia pneumoniae, may play a role in the narrowing of coronary arteries. But whether infectious agents play an important role in this process isn’t well-defined because other research has failed to confirm this link. It’s also unclear whether inflammation of the arteries caused by an infection or other factor underlies coronary artery disease or accelerates it.
How can you know whether you have this silent, potential killer? Your doctor can help answer that question based on test results and your level of risk.
If you have risk factors for coronary artery disease, your doctor may want to test you for coronary artery disease, even if you don’t have signs or symptoms of narrowed arteries. You may be referred to a cardiologist, a doctor who specializes in diagnosing and treating cardiovascular problems. The term cardiovascular refers to your body’s circulatory system — your heart, arteries and veins.
In addition to a physical examination, taking your medical history and routine blood tests, your doctor may recommend these tests to diagnose coronary artery disease:

• Electrocardiogram (ECG). In this test, which is sometimes called an EKG, patches with wires (electrodes) are attached to your skin to measure electrical impulses given off by your heart. This test can show evidence of a previous heart attack or one that’s in progress. It can also yield other useful information, such as the status of your heart’s electrical system. ECG readings taken continuously over a period of 24 hours or longer may help detect silent ischemia. This technique is called ambulatory electrocardiography monitoring, or Holter monitoring. Electrodes attached to your chest are connected to a portable monitor — about the size of a paperback book or smaller — that attaches to your belt or is carried by a shoulder strap. You wear the monitor for 24 hours as you go about your normal activities. Recorded abnormalities may show evidence of inadequate blood supply to your heart.
• Echocardiogram. This test uses sound waves to produce an image of your heart. An echocardiogram can help identify whether an area of your heart has been damaged from lack of blood supply by assessing how well that area moves during each heartbeat. When combined with a stress test, an echocardiogram can also help identify areas of diminished blood flow to your heart.
• Stress test. Stress tests help measure whether your heart is getting adequate blood supply. They may be used to evaluate symptoms such as chest pain or shortness of breath during exertion. Or if you have significant risk factors for coronary artery disease — even if you have no symptoms — a stress test can be used as a screening tool. There are several kinds of stress tests. During an exercise stress test, you walk on a treadmill or pedal a stationary bike while an ECG records your heart’s response to an increasing workload. For people who can’t exercise, a medication may be used to “stress” the heart and mimic the effects of exercise instead. Doctors also sometimes use imaging tests — an echocardiogram or a nuclear scan — to provide additional information by generating pictures of your heart during and after exercise or pharmacologic stress.
• Coronary angiography (or arteriography). This has long been considered the definitive test for coronary artery disease. It can show specific sites of narrowing in coronary arteries. A small tube (catheter) is inserted into an artery in your arm or groin and threaded to your heart. A dye is injected into the catheter. As the dye flows through your coronary arteries, your doctor can see narrow areas and blockages with the help of X-rays.
• Coronary magnetic resonance angiography. This technique uses magnetic waves to produce a three-dimensional image of your coronary arteries to check for narrowings or blockages. This technique is still being developed, but it has the advantage of producing images of your coronary arteries with a noninvasive procedure.
• Nuclear scan. This test also helps identify blood flow problems to your heart. Trace amounts of radioactive material, such as thallium or a compound known as Cardiolite, are injected into your bloodstream. Special cameras can detect areas in your heart that receive less blood flow.
• Electron beam computerized tomography (EBCT). This test, also called an ultrafast CT scan, can detect calcium within plaques that narrow coronary arteries. Most, but not all, plaques contain some calcium. If a substantial amount of calcium is discovered, coronary artery disease is likely.

If your doctor finds that you have coronary artery disease, several treatment approaches are possible, depending on the seriousness of the disease. Many people are able to manage coronary artery disease with lifestyle changes and medications. Other people with severe coronary artery disease may need coronary angioplasty or surgery.

Treating Ischemic heart disease

Lifestyle Changes
Although great advances have been made in treating coronary artery disease, changing your habits remains the single most effective way to stop the disease from progressing. Here are the most beneficial changes you can make:

• Don’t smoke. Smoking is a major risk factor for coronary artery disease. Quitting smoking dramatically lowers your risk of a first or second heart attack.
• Improve your diet. If you know that you have coronary artery disease, changing your diet to one low in fat — especially saturated fat — and cholesterol will help reduce high blood cholesterol, a primary cause of atherosclerosis. It’s important to keep your cholesterol low after a heart attack to help lower your risk of having another one. Eating less fat should also help you lose weight. If you’re overweight, losing weight can help you further lower blood cholesterol. Eating a diet rich in fruits and vegetables and having at least one to two servings of fish a week also can reduce your risk of a heart attack.
• Exercise regularly. Even moderate amounts of physical activity — 30 minutes a day — can lower your risk of death from coronary artery disease. However, people with severe coronary artery disease may need to restrict their exercise somewhat. If you have coronary artery disease, check with your doctor to find out what kinds of exercise are best for you.

Medications for Ischemic heart disease

In addition to lifestyle changes, your doctor may recommend drug therapy to treat coronary artery disease. Medications to prevent or treat coronary artery disease include:

• Cholesterol-lowering drugs. Cholesterol is a large part of the deposits that can narrow heart arteries. A high level of cholesterol in your blood increases your risk of coronary artery disease. Cholesterol-lowering drugs, also called lipid-lowering drugs, help lower the level of “bad” cholesterol in your blood while raising the level of “good” cholesterol. One type of cholesterol, HDL, actually helps protect against coronary artery disease. Examples of cholesterol-lowering drugs include statins, niacin, fibrates and bile acid sequestrants.
• Aspirin. Aspirin, as well as other blood thinners, can reduce the tendency of your blood to clot, which may help prevent obstruction of your coronary arteries.
• Beta blockers. These drugs slow your heart rate and decrease blood pressure, which in turn decreases your heart’s demand for oxygen. Beta blockers also have been shown to reduce the risk of death in people during and after a heart attack. In addition, they’re beneficial for people with a weakened heart muscle and congestive heart failure.
• Nitroglycerin. Nitroglycerin tablets, spray and patches can control chest pain (angina) by both opening up your coronary arteries and reducing your heart’s demand for blood.
• Calcium channel blockers. These medications cause the muscles that surround your coronary arteries to relax and the vessels to open more, increasing blood flow to your heart. They also control high blood pressure.
• Angiotensin-converting enzyme (ACE) inhibitors. These drugs allow blood to flow from your heart more easily, decreasing your heart’s workload. ACE inhibitors are the mainstay treatment for congestive heart failure, which can be a complication of coronary artery disease.
• Other drugs that lower blood pressure, such as diuretics. These medications help open up your blood vessels, including those to your heart, decreasing your heart’s workload.

You may need to take drugs for your heart indefinitely, or you may take medications temporarily until a risk factor for coronary artery disease is better under control.

Procedures to restore and improve blood flow

Types of procedures to improve coronary blood flow (revascularization) include:

• Percutaneous coronary intervention. Also known as angioplasty or stent placement, this is a common treatment for severe blockage of the coronary arteries. Only a small cut is required in your skin to put the catheter into the blood vessel. In this procedure, a doctor inserts a catheter with a small balloon at the tip into an artery in your groin or arm. The catheter is then threaded to the region of a coronary artery that’s narrowed. When the catheter reaches the blockage, the balloon is inflated to widen the artery and improve blood flow. Often small wire tubes (stents) are placed into the area where the blockage occurred to keep the artery from narrowing again. In 2003, the Food and Drug Administration approved the use of drug-eluting stents to help keep coronary arteries open. These stents are covered with a drug that has been shown to reduce the rate of new blockages. However, drug-eluting stents are not appropriate or necessary in all situations, and long-term results are still pending. If percutaneous coronary intervention doesn’t widen the artery or if complications occur, you may need bypass surgery.
• Coronary bypass surgery. This requires open heart surgery. It’s a procedure used to create a route for blood to go around a blocked stretch of a coronary artery. A blood vessel, usually taken from your leg or chest, is grafted directly onto a narrowed artery, bypassing the blocked area. If more than one artery is blocked, a bypass can be done on each. The blood can then go around the obstruction to supply your heart with enough blood to relieve chest pain.
• Atherectomy. In this procedure, a catheter is inserted into an artery. The catheter is equipped with a diamond-shaped device that rotates up to 200,000 times a minute to shave plaques off your artery walls.

Research into new ways to treat coronary artery disease is yielding possibilities. Here are some areas of current research:

• Radiation (brachytherapy) following coronary angioplasty. The majority of people who undergo coronary angioplasty for coronary artery disease receive small wire tubes (stents) to hold the arteries open longer. Generally, stents work well at keeping arteries open. However, in some people, blockage reoccurs following coronary angioplasty. Researchers are studying whether treating narrowed coronary arteries with radiation at the time of angioplasty prevents new blockages from forming.