Atherosclerosis is a disease of the arteries in which fatty material
is deposited in the vessel wall, resulting in narrowing and eventual
impairment of blood flow. Severely restricted blood flow in the arteries
to the heart muscle leads to symptoms such as chest pain.
Atherosclerosis shows no symptoms until a complication occurs.

Atherosclerosis is hardening of a blood vessel from a build up of plaque. Plaque is made of fatty deposits, cholesterol, and calcium. It builds on the inside lining of arteries. This causes the artery to narrow and harden. It affects large and medium-sized arteries.

As plaque builds up it can slow and even stop blood flow. This means the tissue supplied by the affected artery is cut off from its blood supply. This often leads to pain or decreased function. This condition can cause a number of serious health problems. Depending on the location of the blockage, it can cause:

• Coronary heart disease —loss of blood to areas of the heart
• Stroke —loss of blood to areas of the brain
• Peripheral vascular disease —characterized by leg pain with walking

In addition, a hardened artery is more likely to be damaged. Repeated damage to the inner wall of an artery causes blood clots often form. The clots are called thrombi. They can lead to a further decrease in blood flow. In some cases, a thrombus may become so large that it completely closes off the artery. It could also break into clumps, called emboli. These clumps travel through the bloodstream and lodge in smaller arteries, blocking them off. In these cases, the tissue supplied by the artery receives no oxygen. It quickly dies. When this occurs in the heart, it is called a heart attack . In the brain, it is called a stroke .

Long-term atherosclerosis can also cause arteries to weaken. In response to pressure, they may bulge. This bulge is called an aneurysm. If untreated, they can rupture and bleed.

Causes

Atherosclerosis is caused by plaque. Plaque is created by high levels of cholesterol and fat in the blood. Scar tissue and calcium from vessel injury can also add to the plaque build up.

The process leading to this may begin in childhood. It takes decades before it causes serious health problems.

Risk Factors

There are two types of factors that increase your chance of atherosclerosis:

• Risk factors you cannot control:
• Father or brother who developed complications of atherosclerosis before age 55 or mother or sister who developed complications of atherosclerosis before age 65
• Age: 45 and older for men; 55 and older for women
• Sex: men have a greater risk of heart attack than women
• Risk factors you can control:
• High cholesterol —especially LDL ("bad") cholesterol and low HDL (“good”) cholesterol
• High blood pressure
• Cigarette smoking
• Diabetes, type 1 and type 2
• Overweight and obesity
• Lack of physical activity
• Metabolic syndrome —a combination of three out of the following five findings:
• Low HDL-cholesterol—also called good cholesterol
• High triglycerides
• Elevated blood sugar
• Elevated blood pressure
• Increased waist circumference (greater than 40 inches in men and 35 inches in women)

Symptoms

There are none in early atherosclerosis. As the arteries become harder and narrower, symptoms may begin to appear. If a clot blocks a blood vessel or a large embolus breaks free, symptoms can occur suddenly.

Symptoms depend on which arteries are affected. For example:

• Coronary (heart) arteries—may cause symptoms of heart disease, such as chest pain
• Arteries in the brain—may cause symptoms of a stroke such as weakness or dizziness
• Arteries in the lower extremities—may cause pain in the legs or feet and trouble walking

Diagnosis

Most people are diagnosed after they develop symptoms. However, people can be screened and treated for risk factors.

If you have symptoms, your doctor will ask you questions. These will help to determine what arteries might be affected. The doctor will also need to know your full medical history. A physical exam will be done. Tests will depend on which arteries may be involved. Test will be decided based on your symptoms, physical exam, and/or risk factors. Many of these tests detect problems with the tissue that is not getting enough blood. Two common tests that directly evaluate the atherosclerotic arteries are:

• Angiography —a tube-like instrument is inserted into an artery. Dye is injected into the vessel to help determine the degree of blood flow. When done in the heart, this test is called cardiac catheterization .
• Ultrasound —a test that uses sound waves to examine the inside of the body. In this case, the test examines the size and shape of arteries.

Treatment

An important part of treatment is reducing risk factors. To do so, see the steps in the prevention section below. Beyond that, treatment depends on the area of the body most affected.

Treatment may include:

Medications

These include:

• Drugs to interfere with the formation of blood clots, such as aspirin or clopidogrel (Plavix)
• Drugs to control blood pressure if elevated
• Drugs to lower cholesterol if elevated
• Drugs that improve the flow of blood through narrowed arteries, such as cilostazol (Pletal) or pentoxifylline (Trental)

Catheter-based Procedures

These procedures involve a thin tube, called a catheter. It is inserted into an artery. They are most often done for arteries in the heart. They may be used to treat atherosclerosis elsewhere in the body as well. These procedures include:

• Balloon angioplasty —a balloon-tipped catheter is used to press plaque against the walls of the arteries. This increases the amount of space for the blood to flow.
• Stenting—usually done after angioplasty. A wire mesh tube is placed in a damaged artery. It will support the arterial walls and keep them open.
• Atherectomy —instruments are inserted via a catheter. They are used to cut away and remove plaque so that blood can flow more easily. This procedure is not done often these days.

Surgery

Surgical options include:

• Endarterectomy —removal of the lining of an artery obstructed with large plaques. This is often done in carotid arteries of the neck. These arteries bring blood to the brain.
• Arterioplasty— repair of an aneurysm . It is usually done with synthetic tissue.
• Bypass —creation of an alternate route for blood flow. The procedure uses a separate vessel for blood to flow.

Prevention

There are a number of ways to prevent, as well as reverse, atherosclerosis. They include:

• Eat a healthful diet. It should be low in saturated fat and cholesterol. It should also be rich in whole grains, fruits, and vegetables.
• Exercise regularly.
• Maintain a healthy weight. If you are overweight, lose weight.
• Don't smoke. If you smoke, quit .
• Control diabetes.
• If your doctor recommends it, take medication to reduce your risk factors. This may include medicine for high blood pressure or high cholesterol.
• Talk to your doctor about screening tests for atherosclerotic disease of the heart (coronary artery disease) if you have risk factors.

Resources

American Heart Association
http://www.americanheart.org/

National Heart, Lung, and Blood Institute
http://www.nhlbi.nih.gov/

Canadian Cardiovascular Society
http://www.ccs.ca/

References:

American College of Radiology website. Available at: http://www.acr.org/ . Accessed July 7, 2009.

Beers MH, Berkow R. The Merck Manual of Diagnosis and Therapy. Whitehouse Station, NJ: Merck Research Laboratories; 1999.

Heart and stroke facts, 2003. American Heart Association website. Available at: http://www.americanheart.org/presenter.jhtml?identifier=3000333 . Accessed July 7, 2009.
Heart and Stroke Foundation of Canada
http://ww2.heartandstroke.ca/splash/ read more

An atrial septal defect is a congenital heart defect
where the wall between the right and left atria
does not close properly, leaving a hole between the two atria.

Atrial septal defect (ASD) is a congenital birth defect. It is an abnormality in the atria (the upper chambers of the heart). In ASD, the wall between the left and right chambers is not completely closed.

In a developing fetus, there is an opening between the left and right atrium. This opening allows the blood to bypass the lungs. When the baby is born, that opening is normally closed, and blood will flow to the lungs.

In babies born with ASD, blood passes from the left atrium to the right atrium. This eventually can cause problems in the lungs.

ASD occurs in about four out of every 100,000 babies. Those with minor-to-moderate defects may not suffer any complications or symptoms. Very small ASDs close on their own about 90% of the time. Those with more severe defects may have disabilities later in life.

Causes

ASD is a congenital defect. This means that it occurs during fetal development and is present at birth. Some cases may be caused by a genetic defect or abnormality inherited from a parent. Others can be caused by illnesses suffered by the mother during pregnancy.

Most of the time, the cause is unknown.

Risk Factors

Because the cause is largely unknown, there are no known risk factors for this condition.

Symptoms

Symptoms include:

• Fatigue and tiring easily during activity
• Sweating
• Rapid breathing, difficulty breathing, or shortness of breath
• Persistent respiratory infections
• Poor growth
• Heart palpitations
• Poor appetite
• Heart murmur

People with minor-to-moderate defects may show no symptoms. Or, they may not begin to show symptoms until later in life.

Diagnosis

Your doctor will ask about your symptoms and medical history. You will also be examined. Tests may include the following:

• Chest x-ray—a test that uses radiation to take a picture of structures inside the body, especially bones
• Echocardiogram—a test that uses high-frequency sound waves (ultrasound) to examine the size, shape, and motion of the heart
• Doppler image of the heart
• Cardiac catheterization—a tube-like instrument inserted into the heart through a vein or artery (usually in the arm or leg) to detect problems with the heart and its blood supply
• Coronary angiography (patients over age 35 only)—x-rays taken after a dye is injected into the arteries, allows the doctor to look for abnormalities in the arteries
• MRI of the chest—a test that uses magnetic waves to make pictures of structures inside the chest
• Electrocardiogram (ECG, EKG)—a test that records the heart’s activity by measuring electrical currents through the heart muscle

Treatment

ASD may not need treatment if there are few or no symptoms, or if the defect is small. Surgery to close the defect is recommended if the defect causes a large amount of shunting, the heart is swollen, or symptoms occur.

A procedure has been developed to close the defect without surgery.

• The procedure involves placing an ASD closure device into the heart through tubes called catheters.
• The health care provider makes a tiny surgical cut in the groin, then inserts the catheters into a blood vessel and up into the heart.
• The closure device is then placed across the ASD and the defect is closed.

Not all patients with atrial septal defects can have this procedure.

Right after the surgery for ASD, patients should get antibiotics before dental procedures to reduce their risk of developing an infection in the heart. Antibiotics are not needed later on.

Outlook (Prognosis)

In infants, small ASDs (less than 5 mm) will often close on their own or cause no problems. Larger ASDs (8 to 10 mm) most often do not close and may need a procedure.

Important factors include the size of the defect, the amount of extra blood flowing through the opening, and whether the person has any symptoms.

Some patients with ASO may have other congenital heart conditions, such as a leaky valve or a hole in another area of the heart.

Possible Complications

People with a larger or more complicated ASD are at an increased risk for developing a number of problems, including:

• Arrhythmias, particularly atrial fibrillation
• Heart failure
• Heart infections (endocarditis)
• High blood pressure in the arteries of the lungs (pulmonary hypertension )
• Stroke

Prevention

Since the condition is a congenital defect with unknown causes, there are preventive measures. Early diagnosis and early treatment can help prevent complications read more

Definition

Avian influenza is a strain of influenza (sometimes called "the flu", "Bird Flu") that infects birds. In particular, ducks, geese, and chickens may become infected with avian influenza. In Asia, there have been cases of avian influenza that have infected humans.

To date there have been few cases of human illness; however, many infected patients have died because of the type of infection. In addition, there is concern in the medical profession that the virus could become more efficient at infecting humans. Some health experts are concerned that this could eventually cause a pandemic (massive worldwide outbreak) of this disease.

Causes

Viruses belonging to the “A” type of influenza viruses cause avian influenza. Usually, the avian influenza virus only infects birds. However, sometimes the virus can mutate (undergo some chemical and genetic changes). These mutations can allow it to infect pigs or humans. Humans who have close contact with infected birds or pigs can then contract the virus. There is also concern that the virus can mutate sufficiently to allow it to be passed between humans.

The virus is not contracted through eating poultry, eggs, or pork products. It is currently passed through contact with the saliva, nasal secretions, or droppings of infected animals.

Risk Factors

The following factors increase your chances of developing avian influenza. If you have any of these risk factors, tell your doctor:

• Close contact with infected animals, such as:
  
  • Ducks
  • Geese
  • Chickens
  • Turkeys
  • Pigs

Symptoms

If you experience any of these symptoms, do not assume it is due to avian influenza. These symptoms may be caused by other, less serious health conditions. If you experience any one of them, see your physician. Symptoms may include:

• Flu symptoms such as:
  
  • Fever
  • Chills
  • Cough
  • Sore throat
  • General aches
• Eye infections
• Pneumonia
• Acute respiratory distress syndrome
• Simultaneous failure of organs, such as kidney, liver, lungs, and heart
• Problems with blood clotting

Diagnosis

Your doctor will ask about your symptoms and medical history, and perform a physical exam. The types of blood tests available at most clinics and hospitals will be able to identify the presence of an influenza virus, but most laboratories do not have the equipment necessary to specifically identify the virus that causes avian influenza. Samples are usually sent to the Centers for Disease Control in Atlanta, Georgia where the avian influenza virus can be identified.

Treatment

Talk with your doctor about the best treatment plan for you. Research is still being done to find an antiviral agent that works against the virus that causes avian influenza. Some antiviral agents (amantadine and rimantadine) are ineffective against the virus. Thus far, it appears that oseltamivir and zanamivir may work against the avian flu virus.

Prevention

To help reduce your chances of getting avian influenza, take the following steps:

• Avoid traveling to areas where there are avian influenza outbreaks.
• Avoid contact with potentially infected poultry or swine, such as at farms or open-air markets.
• Because egg shells may be contaminated with bird droppings, avoid eating raw eggs.
• Cooked poultry will not transmit the avian influenza virus, but raw poultry could be contaminated with bird droppings, saliva, or mucus. Cook poultry thoroughly, and carefully clean your hands and all cooking surfaces, utensils, and cutting boards.
• Use excellent handwashing techniques if you might be in an area where exposure to the avian influenza virus is possible
• Use a hand sanitizer if clean water is not available for washing.

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