Atherosclerosis

Overview of Atherosclerosis

Atherosclerosis also known as arteriosclerosis, is a medical condition in which narrowing of arteries (blood vessels that carry nutrients and oxygen from heart to the body organs) occur due to the deposition of plaque or atheroma. The Urdu meaning of atherosclerosis is, ‘صلابت شریان’.Plaque is sticky in nature and consists of fat, calcium, cholesterol and other substances of blood. Plaque builds up inside your arteries making the arteries harder, narrower and thicker than normal. Whereas, healthy arteries are wide and elastic. As a result of plaque, blood flow is restricted and limits the supply of oxygenated blood to the body organs. The condition can be serious if plaque bursts, this results in blood clotting leading to other serious medical conditions i.e. strokes and heart attacks.
Atherosclerosis is a slow process that may start at an early age and predominantly doesn’t show any symptoms, however it can rapidly progress.

Occurrence

As it is a predominantly asymptomatic condition, therefore it is hard to determine its accurate incidence. According to a report, 75% of the heart attacks occur due to plaque rupture that affects women of age above 50 years and men over 45 years.
Risks and incidence of atherosclerosis fluctuate between different ethnicities in the South Asian population. As per studies, Urdu speaking people are most likely to develop atherosclerosis followed by Punjabis and Pathans. Urbanization, genetic profile and physiological makeup are the main factors that could be a risk to increase cardiovascular events.

Signs and Symptoms of Atherosclerosis

Atherosclerosis symptoms are visible only in late-stage or extreme conditions when arteries become clogged and can’t supply enough blood to the body's organs. However, the condition starts to develop at the early age but usually, it takes years for symptoms to turn out to be noticeable.
The signs and symptoms of atherosclerosis are based on which arteries are affected.

1: Carotid arteries

They supply blood to the brain. Atherosclerosis of the carotid arteries causes a stroke. Symptoms that appear suddenly, include:

  • Breathing difficulty
  • Headache
  • Weakness
  • Paralysis
  • Facial numbness

2: Coronary arteries

They supply blood to the heart. When atherosclerosis affects the coronary artery, the blood supply to the heart is restricted which may cause heart failure or angina attack.

Symptoms include;

  • Chest pain
  • Extreme anxiety
  • Faintness
  • Coughing
  • Vomiting

3: Renal arteries

They supply blood to the kidneys. Atherosclerosis of renal arteries causes kidney disease. A person with chronic kidney disease may experience the following symptoms:

  • loss of appetite
  • difficulty in concentration
  • high blood pressure
  • swelling in hands and feet

4: Peripheral arteries

They supply blood to the legs, arms, and pelvis. Atherosclerosis of peripheral arteries increases the risk of a heart attack. Symptoms include:

  • Numbness
  • Limbs pain while walking
  • Tissue death or gangrene (severe cases)

Types of Atherosclerosis

Causes of Atherosclerosis

As atherosclerosis develops slowly, the exact cause is not known. It starts with an injury to the inner side of the artery, that damage is caused by:

  • High blood pressure
  • High triglycerides (fat)
  • Diabetes
  • Smoking
  • Inflammation due to other diseases i.e. lupus, infection, and arthritis.

What Actually Happens in Atherosclerosis?

When an injury occurs, the inner side of an artery is damaged and blood cells start clumping at the injury site. Plaque consists of cholesterol and other cellular substances that also start to deposit at the injury side, resulting in the narrowing and hardening of arteries. Consequently, the blood supply to the body's organs becomes limited due to obstructed arteries.
The plaque lining eventually breaks off and releases fatty deposits and other constituents into the bloodstream. This causes the blood to clot which in turn blocks the blood flow to the body's organs. If blood flow is blocked towards the heart, a heart attack occurs. Similarly, other organs are affected depending on the type of artery affected.

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Risk Factors of Atherosclerosis

Risk factors include:

  • Diabetes type I
  • High LDL (low-density lipoprotein) or bad cholesterol
  • Smoking
  • Family history of heart disease
  • Low physical activity
  • Old age
  • Obesity
  • Stress
  • High level of triglycerides
  • Fat rich diet
  • Intake of excess alcohol

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Prevention

Atherosclerosis can be prevented by adopting a healthy lifestyle. You can prevent this condition by following:

  • Stop Smoking: Smoking causes damage to arteries. You can prevent atherosclerosis and reduce the risk of complications by quitting smoking. 
  • Exercise most days of the week. Regular exercise makes your heart muscles healthy. It can also improve blood circulation and helps in the development of new blood vessels. These vessels form a natural bypass around blocked vessels.
  • Healthy Diet: Healthy diet is necessary to maintain a healthy body and reduce the risks of heart problems. According to The American Heart Association (AHA), a healthy diet includes:
    • A wide range of fruits and vegetables
    • Low-fat dairy products
    • Whole grains
    • Poultry and fish, without skin
    • Non-tropical vegetable oils, such as olive or sunflower oil
    • Nuts and legumes
  • Manage Diabetes: Daily exercise, a balanced diet, and losing weight all help to maintain your blood sugar level. Some people may need medications to maintain their diabetes.
  • Frequent Medical Check-Up: Diabetes, high blood pressure, and high cholesterol levels are some of the main factors causing a sudden heart-related problem. To avoid heart problems such as atherosclerosis, get yourself checked frequently, and tested for any health issues if there is a need.
  • Healthy Weight: Avoid gaining weight, because excess weight puts pressure on your heart and contributes to high cholesterol, high blood pressure, and diabetes.
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Diagnosis

Diagnosis of Atherosclerosis is done by:

  • Physical Examination: During a physical examination, the doctor looks for signs such as:
    • Whooshing sounds (bruits) over your arteries, heard using a stethoscope
    • A weak or absent pulse below the narrowed area of your artery
    • Decreased blood pressure in an affected limb

The doctors recommend the following blood tests on the basis of physical exams.

  • Blood Tests: Blood tests are performed to detect the level of cholesterol and blood sugar. The presence of these substances increases the chances of atherosclerosis. Before the test, you avoid eating for 9-12 hours but can drink water.
  • Doppler Ultrasound: In Doppler Ultrasound*, a special ultrasound device is used to check blood pressure at different points on your arm or leg. This test determines the speed of blood flow and the degree of blockage.

*This test is available in different diagnostic labs and hospitals in Pakistan.

  • Ankle-brachial Index*: This test compares the blood pressure (BP) in the ankle with the BP in the arm. Differences in BP indicate atherosclerosis in peripheral arteries.

*In Pakistan, this test is available at Aga Khan University Hospital.

  • Electrocardiogram (ECG): ECG records the electrical signals as they travel from the electro diagram through your heart. Through ECG onset of previous heart attacks can also be checked.
  • Stress Test: It is also known as an exercise stress test, in which your heart's function is monitored during physical activity. Heart problems can be detected during physical activity because during this your heart pumps harder and faster. Otherwise, heart problems can’t be noticed. This test is performed during walking on a treadmill or riding a bike. In a stress test, your heart rhythm, blood pressure, and breathing are monitored.
  • Cardiac Catheterization and Angiogram: This test is performed to check your coronary arteries. It can show if the arteries are narrowed or if there is any blockage. A liquid dye is injected into the heart through a catheter. It is fed through an artery in your leg or arm, to the heart's coronary arteries. After filling with dye, the arteries become visible on the X-ray. The doctor can notice any blockage if present.
  • Other Imaging Tests: for the detailed study of arteries various imaging tests such as MRI scan, CT scan, and ultrasound are performed. These tests can show the hardening and narrowing of large arteries, aneurysms, and calcium accumulation in the artery walls.

Treatment of Atherosclerosis | When to Consult a Doctor

The treatment of atherosclerosis involves lifestyle changes, medication, and surgery (in severe cases).

1: Lifestyle Changes

Some lifestyle changes reduce the risk of atherosclerosis. These include;

  • Avoid smoking
  • Regular exercises
  • Consume healthy diet
  • Maintain a healthy weight
  • Avoid the consumption of alcohol
  • Limit the use of fat-containing food
  • Eat fish or omega-3 fatty acids
  • Manage stress

2: Medication

Medicines prescribed for atherosclerosis include:

  • Anticoagulants: They inhibit blood clotting, also known as blood thinners e.g. warfarin and heparin.
  • Antiplatelets: They inhibit the platelets to stick together in blood or prevent platelet clotting e.g. ticlopidine, clopidogrel, and dipyridamole.
  • Cholesterol-lowering medicines: They lower the level of low-density lipid (LDL) cholesterol and fats in the blood. These include; Statin (simvastatin, pravastatin, and atorvastatin), bile acid sequestrants (colestipol, cholestyramine, and colesevelam), and nicotinic acid.
  • Blood pressure medicines: In case of high blood pressure, medicines for lowering blood pressure are prescribed.

Disclaimer! Please do not use any of these medicines on your own, as they are mentioned here just for your information. Always consult your doctor for the treatment of a disease.

Surgery

Surgery is the last option if medications did not work. It includes coronary angioplasty and coronary artery bypass.

1: Coronary Angioplasty

A catheter (thin tube) is inserted into the blood vessel going toward the heart. The tube opening (balloon) is then inflated to open the obstructed vessel for increased blood flow. Angioplasty can be performed in vessels present elsewhere in the body depending on the artery affected.

Several procedures for coronary intervention include:

  • Balloon angioplasty: a balloon is inflated inside the blocked area of the artery to open the obstructed artery.
  • Atherectomy: a device at the end of the catheter is present that will trim the blocked area inside the artery for increased blood flow.
  • Coronary artery stent: a tiny mesh coil is inserted into the blocked artery and left in place to keep open the obstructed area inside the artery.
  • Laser angioplasty: laser is used to open the blocked artery.

2: Coronary Artery Bypass

The procedure performed by a Cardiac Surgeon involves grafting, in which a piece of healthy vein is taken from elsewhere in the body and attaching it as a bridge or bypass i.e. above or below the blocked area of the obstructed artery. It will allow the blood to flow smoothly without blocking.
A healthy vein is usually taken from the chest wall or leg. Single or sometimes more veins are required for single bypass surgery.
Coronary artery bypass surgery is performed in heart patients who have had angina due to blockage in the coronary artery.