High-cholesterol diet can cause Atherosclerosis or narrowing of arteries. Learn more about Atherosclerosis symptoms, types, and treatment from Cardiac surgeons.

Atherosclerosis

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Ismail Munir

Overview

The American Heart Association defines atherosclerosis as the hardening and narrowing of arteries due to buildup of fatty deposits within its walls<a href="#accordion">[1]</a>. It is derived from the Greek word &#39;athero&#39; which translates to gruel or wax. This refers to the sticky plaques formed due to the accumulation of <a href="https://merisehat.pk/disease/cholesterol">cholesterol</a>, fat, calcium, cellular waste, and fibrin. On the other hand, &#39;sclerosis&#39; means hardening; plaque formation results in hardening and narrowing of the arteries. Therefore, making atherosclerosis a life-threatening condition.

&nbsp;

The chronic arterial disease is a leading cause of cardiovascular disease (CVD), which itself is the most common cause of mortality worldwide. In 2019, an estimated 17.9 million people died due to CVDs<a href="#accordion">[2]</a>. Majority of these deaths occurred in low- and middle-income countries.&nbsp;

&nbsp;

The South Asian region in particular has a higher risk of atherosclerotic cardiovascular disease. A cross-sectional study conducted among the Pakistani population, found 78% of the study participants at high risk of atherosclerosis<a href="#accordion">[3]</a>. Globally, approximately 50% of people aged 40 and above are at risk of developing atherosclerosi<a href="#accordion">[4]</a>.&nbsp;

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Atherosclerosis mostly manifests as ischemic heart disease, ischemic stroke, or peripheral artery disease. However, the incidence and mortality from these life-threatening diseases have significantly dropped among high-income countries<a href="#">[5]</a>. Several low- and middle-income countries have also reported a decline in deaths due to stroke.&nbsp; However, Eastern Europe and Asia continue to see a rise in cases. The decrease in high-income regions is linked to healthy lifestyle changes and better management of chronic diseases such as<a href="https://merisehat.pk/disease/hypertension-57"> high blood pressures</a>, high cholesterol, and <a href="https://merisehat.pk/disease/diabetes-type-1-and-2">diabetes</a>.&nbsp;

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Atherosclerosis is not to be confused with arteriosclerosis. Arteriosclerosis is a general term for a group of conditions that cause hardening of the arteries. It results from several different causes and has various types. On the other hand, atherosclerosis is a common type of arteriosclerosis, and develops from plaque buildup. 
&nbsp;

In atherosclerosis, plaque formation can occur in various large- or medium-sized arteries across the body. Based on the arteries affected, the disease is divided into two types: 
&nbsp;

<ul>
	<li>Coronary Artery Atherosclerosis - As the name implies, coronary artery atherosclerosis is characterized by plaque formation within the walls of the coronary arteries. Atherosclerosis is the major cause of coronary artery disease (CAD). Although fat deposition begins in childhood, it slowly progresses over the years and then clinically manifests in middle age. The atherosclerotic buildup can obstruct blood flow to the heart, causing myocardial ischemia and even sudden cardiac death.</li>
	<li>Noncoronary Atherosclerosis - It refers to atherosclerosis affecting noncoronary arteries such as those in the brain, arms, legs, pelvis, or kidneys. Many patients do not develop any symptoms or functional disabilities despite having advanced disease. Depending on the artery, different organ systems are affected by plaque formation. 
	&nbsp;</li>
</ul>

Signs And Symptoms

Atherosclerotic changes progress slowly over the years. Therefore, most people either present with symptoms in their middle or late adulthood, or with life-threatening conditions such as stroke or heart attack. A Lancet study, assessing the global prevalence of carotid atherosclerosis, found that 21% of people aged 30-79 years had carotid plaque<a href="#accordion">[6]</a>. This translates to roughly 816 million people worldwide<a href="#accordion">[6]</a>.&nbsp;Moreover, 58 million people had carotid stenosis<a href="#accordion">[6]</a>.

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The signs and symptoms of atherosclerosis vary depending on the type of artery affected.&nbsp;

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Carotid Arteries: These supply blood to the brain. Atherosclerosis of carotid arteries most commonly presents with numbness or weakness in limbs, difficulty speaking, paralysis, headache, vision problems, loss of balance, or drooping facial muscles.&nbsp;

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<a href="https://merisehat.pk/disease/coronary-artery-disease">Coronary Arteries</a>: Since coronary arteries supply the heart, a narrowing or blockage of these arteries can result in a myocardial infarction (MI). Symptoms include <a href="https://merisehat.pk/disease/angina">angina</a> (chest pain), shortness of breath, sweating, nausea or vomiting, pain in jaw, arms, neck, and shoulders, and lightheadedness.&nbsp;

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Peripheral Arteries: These arteries supply the arms, legs, and pelvis; the legs are most commonly affected. Muscle weakness, claudication (pain on walking), and numbness are common symptoms.&nbsp;

 
Renal Arteries: Atherosclerosis of the arteries supplying the kidneys can result in high blood pressure, kidney failure, and <a href="https://merisehat.pk/disease/chronic-kidney-disease">chronic kidney disease (CKD).</a> 
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Causes

Arteries are thick-walled blood vessels responsible for carrying oxygen-rich blood from the heart to other parts of the body. The inner layer of the artery, the endothelium, is vulnerable to damage or injury. The following can damage the artery&#39;s endothelium: 
&nbsp;

<ul>
	<li>Smoking</li>
	<li><a href="http://merisehat.pk/disease/obesity">Obesity</a></li>
	<li>High blood pressure<a href="https://www.merisehat.pk/disease/hypertension-57/" target="_blank">&nbsp;</a></li>
	<li>High <a href="https://merisehat.pk/disease/cholesterol">cholesterol</a> levels</li>
	<li>Inflammatory conditions such as lupus, arthritis</li>
</ul>

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A damaged endothelium allows cholesterol, blood cells, and fat to clump together and form a plaque at the injury site. Over time, the plaque can harden and cause narrowing of the arteries. As a result, there is restricted blood flow to that area. In advanced cases, the plaque can become big enough to block the vessel, completely cutting off the blood supply to that area. Moreover, the plaque can also result in a bulge in the artery wall, called aneurysm. Although most aneurysms are asymptomatic, in case of rupture they can present with internal bleeding. The abdominal aorta is the most common site of an atherosclerotic aneurysm.

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The fatty deposits themselves also pose a risk to a person&#39;s health. In some instances, these plaques can break off and form a thrombus (blood clot). This thrombus can then go and block off the blood supply in other parts of the body. Furthermore, plaques can also rupture and cause a blood clot to form at the injury site. 
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Diagnosis

Since atherosclerosis is slowly progressing, people can remain asymptomatic for years. However, those with risk factors should be tested regularly. Since there are no screening programs for atherosclerosis, diagnostic tests are often conducted once a person presents with disease symptoms.&nbsp;

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After taking a complete history and conducting a physical exam, a doctor may suggest one or more of the following tests:

<ul>
	<li>Blood Tests - Multiple blood tests are conducted, and they help measure blood cholesterol, glucose, protein, and lipid levels. Abnormal levels are indicative of the risk of atherosclerosis.</li>
	<li>Chest X-Ray - An X-ray allows visualization of the heart, lungs, and vessels. Thus, helping reveal signs of heart failure.&nbsp;</li>
	<li>Electrocardiogram (ECG Or EKG) - An ECG measures the electrical activity of the heart. It allows for checking of the heart rate and signs of a current or previous heart attack.&nbsp;</li>
	<li>Echocardiogram - Sound waves are used to show how well the heart functions and the blood flows through the arteries.&nbsp;</li>
	<li>Doppler Ultrasound - The test measures the blood pressure at various points in the arms or legs.&nbsp;</li>
	<li>Ankle/Brachial Index - Doctors often use this test to diagnose peripheral artery disease. It compares the blood pressure in the ankles with that in the arm.&nbsp;</li>
	<li>Exercise Stress Test - Also called exercise tolerance test, it monitors the heart rate and blood pressure while a person walks on a treadmill or rides a stationary bike. Since the person is connected to an ECG, the electrical activity of the heart is also recorded. If a person is unable to exercise, they are given medicines that can mimic the effect of exercise. The stress test allows doctors to look for signs of coronary artery disease.</li>
	<li>Cardiac Angiogram - A contrast dye is injected into the arteries and then an X-ray allows visualization of any narrowing or blockage.&nbsp;</li>
	<li>MRI Or CT Scan - These scans create images of the various organs in the body and can reveal the hardening or narrowing of large arteries.</li>
</ul>

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Treatment

Treatment of atherosclerosis involves a combination of medications, lifestyle changes such as diet, and surgery.&nbsp;

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<h5>Medications&nbsp;</h5>

Common medications used to treat atherosclerosis include: 
&nbsp;

<ul>
	<li>Cholesterol Lowering Drugs - Statins are the most commonly prescribed medication to help lower cholesterol levels and prevent atherosclerosis. The aim of any cholesterol medication is to keep low-density lipoprotein (LDL) levels within range as it is implicated in fatty deposit buildup in the arteries.&nbsp;</li>
	<li>Blood Pressure Medications - These medications cannot reverse atherosclerosis; they maintain <a href="https://merisehat.pk/disease/hypertension-57">blood pressure</a> within the normal range to prevent complications of the disease.&nbsp;</li>
	<li>Blood Thinners - Medications such as aspirin prevent clot formation by reducing the clumping of platelets in the arteries. A dose of 75-162mg is generally recommended for adults with atherosclerotic cardiovascular disease<a href="#accordion">[7]</a>. However, the drug increases one&#39;s risk of bleeding and should be prescribed with caution.&nbsp;</li>
	<li>Other Medications - Doctors may also prescribe beta-blockers, medications to control diabetes, and medicines to help treat symptoms of atherosclerosis.&nbsp;&nbsp;</li>
</ul>

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It is important to consult a healthcare professional before starting any drug. Never discontinue a drug without a professional opinion.&nbsp;

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<h5>Lifestyle Changes&nbsp;</h5>

According to the American Heart Association, healthy lifestyle changes can decrease the risk of subclinical atherosclerosis in middle age<a href="https://merisehat.pk/disease/hypertension-57">[8]</a>. These include dietary changes, physical activity, and quitting smoking. A healthy diet should consist of more fruits and vegetables, whole grains, low-fat dairy products, fish, and less salt, sugar, and trans fats. Moreover, 30 minutes of daily (or five days a week) exercise is recommended to improve blood flow and lower the risk of conditions that can increase atherosclerosis risk.&nbsp;

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<h5>Surgery&nbsp;</h5>

In severe cases, doctors may perform surgery to restore blood flow through the arteries. These include: 
&nbsp;

<ul>
	<li>Angioplasty And Stent - Also called percutaneous coronary intervention (PCI), the procedure is used to open a blocked artery. A catheter and a balloon are inserted into the artery to widen it. A stent is usually inserted to keep the artery open.&nbsp;</li>
	<li>Endarterectomy - It is the surgical removal of fatty deposits from within the artery, along with its inner lining. It is most commonly conducted on carotid arteries and those in the legs.</li>
	<li>Atherectomy - This minimally invasive procedure involves removing the plaque using a rotating blade.&nbsp;</li>
	<li>Thrombolytic Therapy - A medication that dissolves blood clots is injected into the arteries.&nbsp;</li>
	<li>Bypass Surgery - This is a major surgery where surgeons take a healthy blood vessel from the leg or chest to create a bypass around the blocked or narrowed artery. This bypass helps redirect blood flow around the blockage. Synthetic grafts can also be used to create the diversion.&nbsp;</li>
</ul>

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Although the hardening of arteries is irreversible, a combination of the above treatments can help slow down disease progression and prevent complications. 
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Similar to the signs and symptoms, complications of atherosclerosis depend on the arteries that are affected. Complications mostly result from a blockage of the affected arteries. 
&nbsp;

<ul>
	<li>Coronary Arteries - Narrowing or blockage of the coronary arteries can result in coronary artery disease angina, myocardial infarction (MI), or heart failure.&nbsp;</li>
	<li>Carotid Arteries - A transient ischemic attack (TIA) is the most common complication and often leads to a stroke.</li>
	<li>Peripheral Arteries - Peripheral artery disease results from narrowing of the arteries in the arms or legs. Circulation problems cause sensory issues and an increased risk of injuries, burns, or frostbite. Moreover, in some cases, poor circulation can also cause gangrene.</li>
	<li>Renal Arteries - Chronic kidney disease is a common complication of atherosclerosis in the renal arteries. It may present with swelling of hands and feet, loss of appetite, and difficulty concentrating.</li>
	<li>Aneurysms - An aneurysm is a bulge in the blood vessel wall. Plaques can cause aneurysms which often rupture and result in life-threatening internal bleeds.&nbsp;</li>
	<li>Embolism - This occurs when a piece of plaque breaks off and travels to another part of the body via the bloodstream. It can then block a blood vessel. 
	&nbsp;</li>
</ul>

The following factors damage the endothelium of the arteries and contribute to plaque buildup:

<ul>
	<li>Age</li>
	<li>Family history of heart disease</li>
	<li><a href="https://merisehat.pk/disease/hypertension-57">Hypertension</a></li>
	<li>High cholesterol</li>
	<li>High levels of C-reactive protein (often present in inflammatory conditions)</li>
	<li>Obesity</li>
	<li>Smoking and Alcohol</li>
	<li><a href="https://merisehat.pk/disease/sleep-apnea-91">Sleep apnea</a></li>
	<li>Lack of exercise and unhealthy diet</li>
</ul>

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The following measures can help prevent plaque formation and ultimately the development of several complications: 
&nbsp;

<ul>
	<li>Eating a healthy diet</li>
	<li>Exercising regularly</li>
	<li>Maintaining a healthy weight</li>
	<li>Quitting smoking</li>
	<li>Managing stress</li>
	<li>Treating conditions such as <a href="https://merisehat.pk/disease/hypertension-57">hypertension</a>, <a href="https://merisehat.pk/disease/obesity">obesity</a>, <a href="https://merisehat.pk/disease/diabetes-type-1-and-2">diabetes</a>, and high cholesterol 
	&nbsp;</li>
</ul>

Key Points

<ul>
	<li>Atherosclerosis is characterized by the buildup of sticky plaques within the walls of the arteries. These plaques are formed of fat, calcium, fibrin, cellular waste, and cholesterol. They can cause narrowing of the vessels or even obstruction.&nbsp;</li>
	<li>Signs and symptoms of the disease depend on the arteries affected. Common conditions that can result from atherosclerosis include coronary artery disease, peripheral artery disease, ischemic stroke, and chronic kidney disease.&nbsp;</li>
	<li>Common risk factors of the disease are aging, obesity, smoking, hypertension, high cholesterol levels,&nbsp;</li>
	<li>Atherosclerosis is treated with a combination of lifestyle changes and medications such as anti-hypertensives, statins, and aspirin. In severe cases, procedures such as angioplasty, endarterectomy, and bypass surgery may be advised. 
	&nbsp;</li>
</ul>

[1] American Heart Association, 2020. Atherosclerosis. [Online]

[2] WHO, 2021. Cardiovascular diseases (CVDs). [Online]

[3] Hassan, K. et al., 2019. Predicting the risk of atherosclerotic cardiovascular disease (ASCVD) in Pakistani population. Clinical Epidemiology and Global Health, Volume 7, pp. 184-187.

[4] Tuzcu, E. M. et al., 2001. High Prevalence of Coronary Atherosclerosis in Asymptomatic Teenagers and Young Adults. Circulation, 103(22).

[5] Herrington, W. et al., 2016. Epidemiology of Atherosclerosis and the Potential to Reduce the Global Burden of Atherothrombotic Disease. Circulation Research, 118(4).

[6] Song, P. et al., 2020. Global and regional prevalence, burden, and risk factors for carotid atherosclerosis: a systematic review, meta-analysis, and modelling study. The Lancet, 8(5), pp. E721-E729.

[7] Fang, J. et al., 2015. Use of Low-dose Aspirin as Secondary Prevention of Atherosclerotic Cardiovascular Disease Among US Adults (From the National Health Interview Survey, 2012). The American journal of cardiology, 115(7).

[8] Spring, B. et al., 2014. Healthy Lifestyle Change and Subclinical Atherosclerosis in Young Adults - Coronary Artery Risk Development in Young Adults (CARDIA) Study. Circulation, 130(1).