Atherosclerosis Explained

Atherosclerosis is often called a silent condition because it typically produces no noticeable symptoms during its early stages. Plaque builds up gradually inside the arteries over many years, and most people remain unaware of its presence until a blockage becomes significant enough to interfere with blood flow. When symptoms do appear, they depend entirely on which arteries are affected and how severely blood flow is restricted.

When atherosclerosis affects the coronary arteries, which supply oxygen-rich blood to the heart muscle, the most common symptom is angina — a sensation of pressure, squeezing, fullness, or pain in the centre of the chest. This discomfort may also radiate to the shoulders, arms, neck, jaw, or back. Angina is often triggered by physical exertion, emotional stress, heavy meals, or cold weather and typically subsides with rest. Some people describe it as a heavy weight on the chest or a burning sensation rather than sharp pain. Shortness of breath, especially during activity, is another common sign when the heart is not receiving enough oxygen.

When the carotid arteries that supply the brain are affected, symptoms may include sudden weakness or numbness on one side of the body, facial drooping, difficulty speaking or understanding speech, sudden confusion, vision loss in one eye, or dizziness. These symptoms can indicate a transient ischaemic attack (often called a mini-stroke) or a full stroke and require immediate medical attention.

When atherosclerosis narrows the arteries in the limbs — most often the legs — a condition known as peripheral arterial disease develops. The hallmark symptom is intermittent claudication: a cramping, aching, or tiredness in the leg muscles, particularly the calves, that occurs during walking or exercise and resolves with rest. As the disease progresses, pain may persist even at rest. The affected limb may feel cooler to the touch, the skin may appear pale or bluish, and sores or wounds on the feet or toes may heal slowly or not at all. In advanced cases, tissue death (gangrene) can occur.

When the renal arteries that supply the kidneys are affected, the result can be poorly controlled high blood pressure and a gradual decline in kidney function. These changes are often detected through blood tests and blood pressure monitoring rather than through symptoms the person feels directly.

Other general symptoms that may accompany advanced atherosclerosis include fatigue, generalised weakness, and — when blood flow to the brain is chronically reduced — difficulty concentrating or mental confusion. It is important to recognise that many people with atherosclerosis experience no symptoms at all until a critical event such as a heart attack or stroke occurs. This is why routine health screenings, particularly for those over 40 or with risk factors, are so important for early detection.

Atherosclerosis develops when the inner lining of the arteries, known as the endothelium, becomes damaged and triggers a complex inflammatory response. This damage allows cholesterol, particularly low-density lipoprotein (LDL), to penetrate the artery wall, where it becomes oxidised and attracts immune cells such as macrophages. These cells engulf the oxidised cholesterol and transform into foam cells, which accumulate and form the earliest visible sign of atherosclerosis: the fatty streak. Over time, this collection of lipids, inflammatory cells, and smooth muscle cells grows into a fibrous plaque with a lipid core. The artery wall thickens and loses its natural elasticity, and the channel through which blood flows becomes narrower.

Chronic high cholesterol is the primary driving force behind plaque formation. When LDL cholesterol levels remain elevated over many years, the rate of lipid deposition in the artery wall exceeds the body’s ability to remove it. High-density lipoprotein (HDL) cholesterol, by contrast, helps transport cholesterol away from the arteries and toward the liver for processing, which is why higher HDL levels are considered protective.

High blood pressure, or hypertension, contributes to atherosclerosis by subjecting the artery walls to excessive force with each heartbeat. This mechanical stress damages the delicate endothelial lining, creating sites where plaque is more likely to form. Over time, untreated hypertension also causes the arterial walls to become thicker and stiffer, further accelerating the disease process.

Smoking and tobacco use are among the most powerful risk factors for atherosclerosis. The chemicals in tobacco smoke damage the endothelium directly, reduce the level of protective HDL cholesterol, increase LDL cholesterol oxidation, promote blood clot formation by making platelets stickier, and reduce the amount of oxygen carried in the blood. Even exposure to secondhand smoke carries significant risk.

Diabetes mellitus dramatically increases the risk of atherosclerosis. Persistently high blood sugar levels lead to the formation of advanced glycation end products, which damage blood vessel walls and promote inflammation. People with diabetes are two to four times more likely to develop cardiovascular disease than those without it, and they tend to develop atherosclerosis at a younger age.

Age is a significant non-modifiable risk factor: the longer the arteries are exposed to the wear and tear of blood flow and the cumulative effects of other risk factors, the greater the likelihood of plaque development. Men over 45 and women over 55 are at increased risk, and the risk rises steadily with each decade of life.

Family history plays an important role. If a first-degree relative (parent or sibling) had early-onset cardiovascular disease — before age 55 in men or before age 65 in women — the risk of developing atherosclerosis is substantially higher. This can reflect inherited tendencies toward high cholesterol, high blood pressure, diabetes, or other metabolic conditions.

Physical inactivity contributes to atherosclerosis through multiple pathways: it is associated with higher blood pressure, less favourable cholesterol profiles, higher blood sugar levels, and greater body weight. Regular exercise, by contrast, strengthens the heart, improves circulation, helps maintain healthy blood pressure, and improves cholesterol balance.

Obesity, particularly excess abdominal fat, is linked to a pro-inflammatory state and insulin resistance, both of which accelerate atherosclerosis. Excess body weight also places additional strain on the heart and is frequently accompanied by other risk factors such as hypertension, high cholesterol, and diabetes.

Additional contributing factors include a diet high in saturated fats, trans fats, and refined carbohydrates; excessive alcohol consumption; chronic stress, which can raise blood pressure and promote inflammatory responses; and sleep disorders such as obstructive sleep apnoea, which are associated with hypertension and metabolic disturbances.

Diagnosing atherosclerosis often begins with a routine health check long before symptoms appear. Because the condition is so common and can remain silent for years, many countries offer cardiovascular screening programmes. In the United Kingdom, for example, the NHS Health Check is available to everyone between the ages of 40 and 74 and is designed to detect early signs of heart disease, stroke, kidney disease, and diabetes.

A thorough physical examination provides the first clues. The doctor will check the pulse in your wrists, neck, groin, and feet, noting whether any pulses are weak or absent — a sign that blood flow may be reduced. They will listen with a stethoscope over the carotid arteries in the neck, the abdomen, and the femoral arteries in the groin for a whooshing sound called a bruit, which indicates turbulent blood flow through a narrowed vessel. The doctor will also examine the legs and feet for signs of poor circulation: cool skin, pale or bluish discolouration, shiny skin, hair loss, and slow-healing sores or ulcers. Blood pressure is measured in both arms, and a significant difference between the two can suggest narrowing of the arteries on one side.

Blood tests are a cornerstone of diagnosis. A lipid panel measures total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides. Fasting blood glucose or HbA1c tests screen for diabetes or prediabetes. High-sensitivity C-reactive protein (hs-CRP) may also be checked, as elevated levels indicate systemic inflammation, which is associated with increased cardiovascular risk.

The ankle-brachial index is a simple, non-invasive test that compares blood pressure readings at the ankle with those at the arm. A lower reading in the ankle suggests that atherosclerosis is narrowing the arteries in the legs. This test is particularly useful for detecting peripheral arterial disease and can be performed in a doctor’s office in just a few minutes.

Doppler ultrasound uses sound waves to create images of blood flow through the arteries. It can show where blockages are located and how severe they are. This is often the first imaging test used because it is painless, does not involve radiation, and provides real-time information about blood flow velocity and direction.

Computerised tomography angiography (CTA) and magnetic resonance angiography (MRA) produce detailed cross-sectional images of the arteries throughout the body. These scans can reveal the location, size, and composition of plaques and can assess how much they are narrowing the vessel lumen. CTA involves a small amount of radiation and the injection of a contrast dye, while MRA uses magnetic fields and may also use contrast.

Cardiac catheterisation with coronary angiography is considered the most definitive test for evaluating atherosclerosis in the heart arteries. A thin, flexible tube called a catheter is threaded through a blood vessel, usually in the groin or wrist, up to the coronary arteries. A contrast dye is injected, and X-ray images are taken to reveal any blockages. This test can also be used to guide treatment — if a significant blockage is found, a stent can often be placed during the same procedure.

An electrocardiogram (ECG or EKG) records the electrical activity of the heart and can reveal evidence of a previous heart attack, abnormal heart rhythms, or signs that the heart muscle is not receiving enough oxygen. It is a quick, painless test that provides valuable baseline information.

An exercise stress test involves walking on a treadmill or pedalling a stationary bicycle while the heart is monitored with an ECG and blood pressure readings. This test helps determine how well the heart performs under increased demand and whether exercise triggers symptoms or ECG changes that suggest reduced blood flow. For those unable to exercise, medication can be used to simulate the effects of exertion on the heart.

Managing atherosclerosis involves a comprehensive approach that addresses the underlying disease process, reduces the workload on the heart and blood vessels, and lowers the risk of serious complications such as heart attack and stroke. Treatment is typically layered, beginning with lifestyle modifications and adding medications as needed, with surgical interventions reserved for advanced cases.

Lifestyle changes form the foundation of atherosclerosis management and are recommended for everyone with the condition, regardless of severity. These changes are not merely general suggestions — they are evidence-based interventions that can slow the progression of plaque buildup, improve symptoms, and significantly reduce cardiovascular risk. Quitting smoking is the single most impactful step a person can take; within one year of stopping, the risk of heart disease drops by approximately half. Regular physical activity — at least 150 minutes of moderate-intensity aerobic exercise per week, such as brisk walking, cycling, or swimming, combined with strength training on two or more days per week — improves circulation, helps control weight, lowers blood pressure, and improves cholesterol levels. Achieving and maintaining a healthy weight reduces strain on the heart and improves metabolic health. Stress management techniques, including mindfulness, meditation, and adequate sleep, can help lower blood pressure and reduce inflammatory responses. Alcohol consumption should be limited to no more than 14 units per week for both men and women.

When lifestyle changes alone are not sufficient to control risk factors, medications are introduced. These are tailored to the individual’s specific risk profile and may include drugs to lower cholesterol, reduce blood pressure, prevent blood clots, or manage blood sugar. Most people with established atherosclerosis will need to take at least one medication long-term, and many will need a combination of several. It is important to take these medications exactly as prescribed, even when feeling well, because they work to prevent future events.

For people with severe blockages or those who experience symptoms that significantly affect their quality of life despite optimal medical therapy, surgical or endovascular procedures may be recommended. The choice of procedure depends on the location and severity of the blockage, the overall health of the patient, and the presence of other medical conditions.

Angioplasty and stenting — collectively known as percutaneous coronary intervention when performed on the heart arteries — involves threading a catheter with a small balloon at its tip through the blood vessel to the site of the blockage. The balloon is inflated to compress the plaque against the artery wall and expand the vessel. A stent, which is a small mesh tube, is typically left in place to keep the artery open. Drug-eluting stents, which slowly release medication, help prevent the artery from narrowing again.

Coronary artery bypass grafting is a surgical procedure used when multiple coronary arteries are severely blocked or when angioplasty is not suitable. A blood vessel is taken from another part of the body — usually the leg, arm, or chest wall — and grafted onto the coronary artery to create a new route for blood to flow around the blockage. This is major surgery performed under general anaesthesia and requires a period of recovery in the hospital, but it can provide lasting relief from symptoms and improve survival in appropriately selected patients.

Carotid endarterectomy is a surgical procedure to remove plaque from the carotid arteries in the neck. An incision is made in the neck, the artery is opened, and the fatty deposits are carefully peeled away. For some patients, carotid angioplasty and stenting may be an alternative.

Atherectomy is a procedure in which a catheter with a rotating blade or laser at its tip is used to shave or vaporise plaque from the artery. It is most commonly used for blockages in the peripheral arteries of the legs when angioplasty alone may not be sufficient.

Thrombolytic therapy involves the injection of a clot-dissolving medication directly into the affected artery. It is used in emergency situations, such as during a heart attack or stroke, to rapidly restore blood flow. Because of the risk of serious bleeding, it is reserved for carefully selected cases.

Several classes of medication are used to manage atherosclerosis and reduce the risk of its complications. These drugs work through different mechanisms, and many people require a combination of two or more to achieve optimal control of their risk factors.

Statins are the cornerstone of cholesterol-lowering therapy. They work by inhibiting an enzyme called HMG-CoA reductase, which plays a central role in the liver’s production of cholesterol. By reducing the liver’s output of cholesterol, statins lower LDL cholesterol levels in the blood — typically by 30 to 50 percent or more, depending on the drug and dose. They also have anti-inflammatory effects that stabilise existing plaques, making them less likely to rupture and cause a heart attack or stroke. Common examples include atorvastatin, rosuvastatin, simvastatin, and pravastatin. Statins are generally well-tolerated, though some people experience muscle aches, which should be discussed with a doctor rather than causing the medication to be stopped abruptly.

Ezetimibe is another cholesterol-lowering medication that works by reducing the absorption of cholesterol from the small intestine. It is often used in combination with a statin when additional LDL lowering is needed or for people who cannot tolerate a high-dose statin.

Bile acid sequestrants, such as cholestyramine and colesevelam, bind to bile acids in the intestine, preventing their reabsorption and forcing the liver to use more cholesterol to produce replacement bile acids. This lowers LDL cholesterol but can cause gastrointestinal side effects and may interfere with the absorption of other medications.

PCSK9 inhibitors are a newer class of injectable medications that dramatically lower LDL cholesterol by blocking a protein that normally degrades LDL receptors in the liver. With more LDL receptors available, the liver is able to clear more LDL from the blood. These drugs are typically reserved for people with very high cholesterol levels or those who cannot tolerate statins.

Antiplatelet medications reduce the risk of blood clots forming in narrowed arteries. Low-dose aspirin (75 to 100 milligrams daily) is the most commonly used antiplatelet drug for people with established atherosclerotic cardiovascular disease. It works by irreversibly inhibiting an enzyme called cyclooxygenase, which reduces the production of thromboxane, a substance that promotes platelet aggregation. Clopidogrel is another antiplatelet drug that is often used in combination with aspirin after a heart attack or stent placement, or as an alternative for those who cannot take aspirin.

Anticoagulant medications, such as warfarin, apixaban, rivaroxaban, and edoxaban, interfere with the blood-clotting cascade and are used in certain situations, such as when atherosclerosis is accompanied by atrial fibrillation or when a blood clot has formed in the heart or a large artery.

Blood pressure medications are often essential. Angiotensin-converting enzyme (ACE) inhibitors, such as ramipril, lisinopril, and perindopril, relax blood vessels by blocking the formation of a hormone called angiotensin II, which normally constricts vessels. They also have protective effects on the heart and kidneys beyond their blood pressure-lowering action. Angiotensin II receptor blockers (ARBs), such as losartan, valsartan, and candesartan, work through a similar mechanism and are an alternative for people who develop a cough with ACE inhibitors.

Beta-blockers, such as bisoprolol, metoprolol, and atenolol, reduce the heart rate and the force of contraction, thereby decreasing the heart’s demand for oxygen. They are particularly valuable for people who have had a heart attack or who experience angina.

Calcium channel blockers, such as amlodipine, diltiazem, and nifedipine, relax the muscles in the artery walls, allowing blood vessels to widen and blood pressure to decrease. They can also help control angina.

Diuretics, sometimes called water pills, help the kidneys remove excess sodium and fluid from the body, reducing blood volume and thereby lowering blood pressure. Thiazide diuretics like bendroflumethiazide are commonly used for this purpose.

For people with diabetes, medications that control blood sugar also play a role in managing atherosclerosis risk. Metformin improves insulin sensitivity and is typically the first-line treatment. SGLT2 inhibitors (such as empagliflozin and dapagliflozin) and GLP-1 receptor agonists (such as liraglutide and semaglutide) have been shown to reduce cardiovascular risk in people with type 2 diabetes, independent of their blood sugar-lowering effects.

Diet is one of the most powerful tools for managing atherosclerosis and supporting overall cardiovascular health. The goal is to reduce the intake of foods that promote plaque formation while increasing the intake of foods that protect the arteries, lower cholesterol, and reduce inflammation.

The Mediterranean diet is among the most extensively studied dietary patterns for heart health. It emphasises abundant consumption of vegetables, fruits, whole grains, legumes, nuts, seeds, and olive oil as the primary source of fat. Fish and seafood are eaten at least twice per week, poultry and eggs in moderate amounts, and red meat only occasionally. Herbs and spices provide flavour instead of salt. This pattern of eating has been shown in numerous large-scale studies to reduce the risk of heart attack, stroke, and cardiovascular death.

The DASH diet (Dietary Approaches to Stop Hypertension) is another well-established heart-healthy eating plan. It emphasises fruits, vegetables, low-fat dairy products, whole grains, fish, poultry, nuts, and beans, while limiting foods high in saturated fat, full-fat dairy products, and sugary beverages. The DASH diet is particularly effective for lowering blood pressure.

Saturated fats, found primarily in red meat, butter, full-fat dairy products, palm oil, and coconut oil, should be limited because they raise LDL cholesterol. Trans fats, which are found in some processed foods, fried foods, and baked goods made with partially hydrogenated oils, are even more harmful — they raise LDL cholesterol while also lowering protective HDL cholesterol — and should be avoided as much as possible.

Soluble fibre is especially beneficial for lowering cholesterol. It binds to cholesterol-containing bile acids in the intestine and helps remove them from the body. Good sources include oats, barley, psyllium, apples, citrus fruits, carrots, beans, lentils, and peas. Aiming for at least 25 to 30 grams of total fibre per day, with 5 to 10 grams coming from soluble fibre, is a reasonable target for heart health.

Omega-3 fatty acids, found in fatty fish such as salmon, mackerel, sardines, trout, and herring, have anti-inflammatory properties and can help lower triglycerides and reduce the risk of irregular heart rhythms. The American Heart Association recommends eating at least two servings of fatty fish per week. For those who do not eat fish, plant-based sources of omega-3s include flaxseeds, chia seeds, walnuts, and hemp seeds.

Sodium intake should be limited, as excess sodium raises blood pressure. The recommended maximum is less than 6 grams of salt per day (about 2.4 grams of sodium), roughly equivalent to one teaspoon. This means limiting processed foods, canned soups, salty snacks, cured meats, and restaurant meals, and using herbs, spices, lemon juice, or vinegar to season food instead of salt.

Added sugars and refined carbohydrates contribute to weight gain, raise triglyceride levels, and increase the risk of diabetes. Sugary drinks, sweets, pastries, white bread, white rice, and many breakfast cereals should be minimised. Replacing refined grains with whole grains — whole wheat bread instead of white, brown rice instead of white, oats instead of sugary cereal — improves fibre intake and has favourable effects on cholesterol and blood sugar.

Alcohol, if consumed, should be limited. Moderate intake — defined as no more than one drink per day for women and two per day for men — has been associated with a lower risk of heart disease in some studies, possibly due to beneficial effects on HDL cholesterol and blood clotting. However, higher levels of consumption increase blood pressure, triglyceride levels, and the risk of stroke, so moderation is key.

Atherosclerosis develops silently over decades, driven by the accumulation of cholesterol-rich plaque within artery walls. High cholesterol, high blood pressure, smoking, diabetes, physical inactivity, and other risk factors accelerate this process, and the consequences of untreated disease can be serious — including heart attack, stroke, peripheral arterial disease, and kidney damage.

Effective management rests on a three-part approach: lifestyle changes (a heart-healthy diet, regular exercise, smoking cessation, weight management), medications (statins, blood pressure drugs, antiplatelet therapy), and, when blockages are severe, surgical procedures such as angioplasty, stenting, or bypass surgery.

Early detection through routine health screenings allows for intervention at a stage when lifestyle changes and medications are most effective. For those already living with the condition, consistent, long-term management can slow disease progression, preserve quality of life, and dramatically reduce the risk of a heart attack or stroke.