During discussions about heart health, you may have heard of phrases along the lines of ‘artery-clogging’, ‘fatty plaque’, and ‘cholesterol clogging up the arteries’, All these phrases refer to a cardiovascular disorder called atherosclerosis (or arteriosclerosis). Atherosclerosis is a progressive disease of the arteries which is caused by the build-up of a substance called plaque in the walls of the arteries. Plaque hardens over time and narrows the arteries, which limits the flow of oxygen-rich blood to other parts of the body.

What makes atherosclerosis dangerous is that it’s a ‘silent’ disease — the gradual narrowing of the arteries does not produce any symptoms. But it can manifest into lifelong diseases like ischemic heart disease or life-threatening events like heart attacks and strokes. South Asians have been shown to be more vulnerable to progressive damage to the arteries during atherosclerosis. The impact of atherosclerosis is also experienced much earlier in South Asians than in Western populations. Moreover, ischemic heart disease, which is a result of atherosclerosis, was responsible for the largest number of heart disease-related deaths in India in 2016.

So, understanding the possible signals, risk factors for, and ways to manage your risk of atherosclerosis can help keep you several steps ahead of this potentially life-threatening cardiovascular disease.

The Science Behind Atherosclerosis

The development of atherosclerosis starts as early as childhood. There are complex biological processes behind the formation of plaque that blocks the arteries:

• The earliest sign of atherosclerosis is the appearance of yellow discolouration on the inner surface of the arteries, which is called fatty streak.
• The formation of fatty streaks happens as a result of endothelial dysfunction. Endothelial cells line the inner layer of all blood vessels. So when these cells get damaged, they allow the entry of low-density lipoprotein (LDL) into the inner layer. LDL may be familiar to you because it’s a component of the infamous artery-clogging ‘bad’ cholesterol. (Find out about good and bad cholesterol here!)
• The fatty streak eventually evolves into the wax-like, fatty plaque. The plaque has a protective capsule surrounding it.
• Plaque poses a double threat:
  • If the protective capsule surrounding the plaque is thick, it is less vulnerable to rupture. Hence, these plaques are called stable plaques. These plaques can cause more pronounced narrowing of the arteries, which results in inadequate supply of oxygen-rich blood to organs.
  • But if the protective capsule is thin, it is more prone to rupture. Such plaques are called unstable or vulnerable plaques. If the capsule ruptures, the inflammatory cells within it can lead to the formation of a blood clot. A blood clot can severely block the blood flow through arteries. In other cases, the plaque itself can break off and get carried by the bloodstream. It may then get stuck in the smaller arteries, completely blocking the blood flow.

Signs and Complications of Atherosclerosis

There are no obvious symptoms for the hardening of the arteries that occurs over time during atherosclerosis. But the progressive narrowing of any of the arteries can lead to a range of health complications, some of which can be potentially life-threatening:

Ischemic heart disease: This happens when the coronary arteries, which are blood vessels supplying the heart, become narrow due to plaque formation. When your heart doesn’t get sufficient oxygen, you may feel pain and discomfort in your chest. This is called angina. These episodes of chest pain may precede or indicate a full-blown heart attack. So, it’s important to be vigilant and act fast if you think you’re experiencing any angina or heart attack symptoms.

Carotid artery disease: If you’re a fan of police procedural TV shows, you may have noticed an officer placing two fingers on the side of the victim’s neck to check if they are still alive. The officers are checking the pulse of the carotid arteries, which are major blood vessels supplying the brain. If these arteries narrow due to plaque or blood clot formation, the cut-off of crucial oxygen to the brain can lead to a stroke. Signs of a stroke include slurred speech, drooping of one side of the face, numbness of one side of the body, dizziness, and breathing difficulties. In addition to the risk of death, a stroke can lead to lifelong complications like vision problems, speech problems, and paralysis.

Peripheral artery disease: This happens when the arteries that carry oxygen-rich blood from the heart to the rest of the body parts (especially the legs) become narrow due to plaque or blood clot formation. When your legs don’t get adequate oxygen levels, you may experience frequent pain and cramping in your legs. Peripheral artery disease can have serious long-term complications like difficulties in managing daily activities, tissue death (or gangrene), and development of sores. Gangrene may require amputations, while sores can be associated with severe infections that can spread to the tissues, muscles, bones, and bloodstream.

Chronic kidney disease: This occurs when the renal arteries (supplying oxygen-rich blood to the kidneys) become narrow. Over time, the progressive narrowing of the renal arteries can adversely affect the functioning of the kidneys. Some signs of chronic kidney disease include more frequent urination, appetite loss, nausea, swollen hands or feet, and trouble concentrating.

Risk Factors for Atherosclerosis

Both non-modifiable and lifestyle-related factors can heighten the risk of atherosclerosis:

**Age**: As you get older, more plaque builds up in the walls of the arteries, which leads to higher vulnerability to serious signs and symptoms. In men, the risk of severe atherosclerosis increases after 45 years. In women, this risk increases after 55 years.

**Family history**: You may be more susceptible to atherosclerosis if your father or brother was diagnosed with a heart condition before the age of 55, or if your mother or sister was diagnosed before the age of 65.

High blood pressure: This allows the entry and trapping of LDL in the inner walls of the arteries, further thickening the layer of plaque.

High **cholesterol** levels: LDL is one of the components of plaque that narrows the arteries. Elevated levels of LDL (‘bad’) cholesterol and lower levels of HDL (‘good’) cholesterol contribute to increased plaque formation.

Diabetes: This promotes the modification of LDL that happens during atherosclerosis, and also causes damage to the endothelial cells lining the arteries. People with diabetes are more likely to experience severe complications related to peripheral artery disease.

Lack of physical activity: Physical inactivity may also increase the risk of diabetes, obesity/overweight, and high blood pressure, which in turn make you more vulnerable to atherosclerosis.

Unhealthy dietary practices: Foods rich in saturated and trans fats can lead to atherosclerosis due to their high LDL cholesterol content. Diets high in salt and refined sugar can also heighten your risk of high blood pressure and diabetes, respectively.

Smoking: The components of cigarette smoke enhance LDL modification and worsen the functioning of the endothelial cells. Smoking can also cause structural damage to the arteries. It contributes to the development of other atherosclerosis risk factors like high blood pressure and high cholesterol levels.

Preventing and Managing Atherosclerosis

Although plaque deposition in the walls of your arteries starts from an early age, leading a healthy lifestyle can significantly reduce your risk of serious atherosclerosis-related complications like heart attacks and stroke. Here are a few lifestyle tips you can follow:

• A healthy diet is key in preventing the aggravation of plaque build-up in the arteries. It is important to reduce the consumption of artery-clogging foods like butter, heavy cream, and red meat as they are loaded with saturated fats, trans fats, and ‘bad’ LDL cholesterol. You should also avoid excess salt and sugar consumption. Find out about a heart-healthy diet here.

• Regular physical activity can be immensely beneficial reducing your risk of overweight/obesity and diabetes. Find out about the importance of physical activity for cardiovascular health here.

• Cholesterol monitoring is important to keep track of your levels of protective HDL cholesterol and artery-clogging LDL cholesterol through regular lipid profile tests. This will enable you to make lifestyle changes and start taking the necessary medications.

• Quit unhealthy, artery-damaging behaviours like smoking and excess alcohol consumption. The positive impacts of quitting smoking on your cardiovascular health come into effect almost immediately. Find out how you can quit smoking here.

Key take-home messages

• Atherosclerosis, which involves the build-up of plaque in and eventual narrowing of the arteries, can start developing from an early age; so it is important to ensure that you and all your family members are proactive about leading a heart-healthy lifestyle
• Atherosclerosis makes you more vulnerable to heart diseases (ischemic heart disease, carotid artery disease, peripheral artery disease) and adverse cardiovascular events (heart attacks, strokes).
• Simple lifestyle changes can significantly reduce your and your family’s risk of atherosclerosis. So remember, don’t take it easy with your and your family’s heart health!

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