Atherosclerosis

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By Medifit Education

ATHEROSCLEROSIS

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ATHEROSCLEROSIS DEFINITION

Atherosclerosis is a chronic vascular disease that may remain asymptomatic for many years leading to the hardening of the arteries due to the accumulation of fat, cholesterol, and other substances in the arterial walls. The condition usually affects medium and large arteries. If untreated the condition may lead to complete occlusion of the vessel leading to cessation of blood supply to the heart or brain. Smoking, alcohol, diabetes, cholesterol and hypertension increase the risk of atherosclerosis.

 

ATHEROSCLEROSIS CAUSES

The exact cause of atherosclerosis isn’t known. However, studies show that atherosclerosis is a slow, complex disease that may start in childhood. It develops faster as you age.

Atherosclerosis may start when certain factors damage the inner layers of the arteries. These factors include:

  • Smoking
  • High amounts of certain fats and cholesterol in the blood
  • High blood pressure
  • High amounts of sugar in the blood due to insulin resistance or diabetes

Plaque may begin to build up where the arteries are damaged. Over time, plaque hardens and narrows the arteries. Eventually, an area of plaque can rupture (break open).

When this happens, blood cell fragments called platelets (PLATE-lets) stick to the site of the injury. They may clump together to form blood clots. Clots narrow the arteries even more, limiting the flow of oxygen-rich blood to your body.

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ATHEROSCLEROSIS PATHOPHYSIOLOGY

Atherosclerosis is a multifocal, smoldering, immunoinflammatory disease of medium-sized and large arteries fuelled by lipids. Endothelial cells, leukocytes, and intimal smooth muscle cells are the major players in the development of this disease. The most devastating consequences of atherosclerosis, such as heart attack and stroke, are caused by superimposed thrombosis. Therefore, the vital question is not why atherosclerosis develops but rather why atherosclerosis, after years of indolent growth, suddenly becomes complicated with luminal thrombosis. If thrombosis-prone plaques could be detected and thrombosis averted, atherosclerosis would be a much more benign disease. Approximately 76% of all fatal coronary thrombi are precipitated by plaque rupture. Plaque rupture is a more frequent cause of coronary thrombosis in men (∼80%) than in women (∼60%). Ruptured plaques are characterized by a large lipid-rich core, a thin fibrous cap that contains few smooth muscle cells and many macrophages, angiogenesis, adventitial inflammation, and outward remodeling. Plaque rupture is the most common cause of coronary thrombosis. Ruptured plaques and, by inference, rupture-prone plaques have characteristic pathoanatomical features that might be useful for their detection in vivo by imaging. This article describes the pathogenesis of atherosclerosis, how it begets thrombosis, and the possibility to detect thrombosis-prone plaques and prevent heart attack.

 

ATHEROSCLEROSIS SYMPTOMS

Atherosclerosis develops gradually. Mild atherosclerosis usually doesn’t have any symptoms.

You usually won’t have atherosclerosis symptoms until an artery is so narrowed or clogged that it can’t supply adequate blood to your organs and tissues. Sometimes a blood clot completely blocks blood flow, or even breaks apart and can trigger a heart attack or stroke.

Symptoms of moderate to severe atherosclerosis depend on which arteries are affected. For example:

  • If you have atherosclerosis in your heart arteries, you may have symptoms, such as chest pain or pressure (angina).
  • If you have atherosclerosis in the arteries leading to your brain, you may have signs and symptoms such as sudden numbness or weakness in your arms or legs, difficulty speaking or slurred speech, or drooping muscles in your face. These signal a transient ischemic attack (TIA), which, if left untreated, may progress to a stroke.
  • If you have atherosclerosis in the arteries in your arms and legs, you may have symptoms of peripheral artery disease, such as leg pain when walking (intermittent claudication).
  • If you have atherosclerosis in the arteries leading to your kidneys, you develop high blood pressure or kidney failure.
  • If you have atherosclerosis in the arteries leading to your genitals, you may have difficulties having sex. Sometimes, atherosclerosis can cause erectile dysfunction in men. In women, high blood pressure can reduce blood flow to the vagina, making sex less pleasurable.

 

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ATHEROSCLEROSIS DIAGNOSIS

Physical Exam

During the physical exam, your doctor may listen to your arteries for an abnormal whooshing sound called a bruit (broo-E). Your doctor can hear a bruit when placing a stethoscope over an affected artery. A bruit may indicate poor blood flow due to plaque buildup.

Your doctor also may check to see whether any of your pulses (for example, in the leg or foot) are weak or absent. A weak or absent pulse can be a sign of a blocked artery.

Diagnostic Tests

Your doctor may recommend one or more tests to diagnose atherosclerosis. These tests also can help your doctor learn the extent of your disease and plan the best treatment.

Blood Tests

Blood tests check the levels of certain fats, cholesterol, sugar, and proteins in your blood. Abnormal levels may be a sign that you’re at risk for atherosclerosis.

EKG (Electrocardiogram)

An EKG is a simple, painless test that detects and records the heart’s electrical activity. The test shows how fast the heart is beating and its rhythm (steady or irregular). An EKG also records the strength and timing of electrical signals as they pass through the heart.

An EKG can show signs of heart damage caused by CHD. The test also can show signs of a previous or current heart attack.

Chest X Ray

A chest x ray takes pictures of the organs and structures inside your chest, such as your heart, lungs, and blood vessels. A chest x ray can reveal signs of heart failure.

Ankle/Brachial Index

This test compares the blood pressure in your ankle with the blood pressure in your arm to see how well your blood is flowing. This test can help diagnose P.A.D.

Echocardiography

Echocardiography (echo) uses sound waves to create a moving picture of your heart. The test provides information about the size and shape of your heart and how well your heart chambers and valves are working.

Echo also can identify areas of poor blood flow to the heart, areas of heart muscle that aren’t contracting normally, and previous injury to the heart muscle caused by poor blood flow.

Computed Tomography Scan

A computed tomography (CT) scan creates computer-generated pictures of the heart, brain, or other areas of the body. The test can show hardening and narrowing of large arteries.

A cardiac CT scan also can show whether calcium has built up in the walls of the coronary (heart) arteries. This may be an early sign of CHD.

Stress Testing

During stress testing, you exercise to make your heart work hard and beat fast while heart tests are done. If you can’t exercise, you may be given medicine to make your heart work hard and beat fast.

When your heart is working hard, it needs more blood and oxygen. Plaque-narrowed arteries can’t supply enough oxygen-rich blood to meet your heart’s needs.

 

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A stress test can show possible signs and symptoms of CHD, such as:

  • Abnormal changes in your heart rate or blood pressure
  • Shortness of breath or chest pain
  • Abnormal changes in your heart rhythm or your heart’s electrical activity

As part of some stress tests, pictures are taken of your heart while you exercise and while you rest. These imaging stress tests can show how well blood is flowing in various parts of your heart. They also can show how well your heart pumps blood when it beats.

Angiography

Angiography is a test that uses dye and special x rays to show the inside of your arteries. This test can show whether plaque is blocking your arteries and how severe the blockage is.

A thin, flexible tube called a catheter is put into a blood vessel in your arm, groin (upper thigh), or neck. Dye that can be seen on an x-ray picture is injected through the catheter into the arteries. By looking at the x-ray picture, your doctor can see the flow of blood through your arteries.

 

ATHEROSCLEROSIS TREATMENT

There is no cure for atherosclerosis, but treatment can slow or halt the worsening of the disease. The major treatment goal is to prevent significant narrowing of the arteries so that symptoms never develop and vital organs are never damaged. If you have high cholesterol that cannot be controlled by diet and exercise, medication may be necessary. The best medicine to lower cholesterol is a statin, also known as a HMG-CoA reductase inhibitor. Statins block an enzyme called HMG-CoA reductase, which controls the production of cholesterol in the liver.

By Medifit Education

www.themedifit.in