Coronary Artery Disease - Symptoms, Causes, Risk factors, Treatment and Prevention

Coronary artery disease definition

Coronary artery disease is a cardiac condition that occurs due to narrowing or blocking of the coronary arteries, which carry oxygen-rich blood to the heart; this can happen due to the deposition of plaque, a fatty material, on the inner walls of the arteries. CAD is also known as coronary heart disease or ischemic heart disease.

Coronary artery disease is typically treated by a cardiologist who is specialized in diagnosing and treating heart conditions.

Coronary artery disease meaning

The word "coronary" is derived from the Latin word "corona," meaning crown. Healthcare experts use it to describe how the blood vessels around the heart surround and protect it, much like a crown protects a king.

Coronary artery disease prevalence

Prevalence of coronary artery disease worldwide

Coronary artery disease (CAD) is the third significant cause of death worldwide, affecting more than 25 crore people. It is estimated that around 14.5 crore men and 11 crore women are living with CHD each year. It is a major cause of both death and disability. Irrespective of its severity, CAD is mostly preventable.

Incidence of coronary artery disease

The incidence of coronary artery disease is approximately 0.9 crore deaths worldwide. In 2021, it was the world's single biggest killer, with around 1 in 7 global deaths.

Prevalence of coronary artery disease in India 

Coronary heart disease (CHD) has become increasingly prevalent in India during the last 60 years. It has increased from 1% to 9-10% in urban areas and less than 1% to 4-6% in rural areas.

Types of coronary artery disease 

Coronary artery disease is divided into three types based on the location of the problem, the degree of blockage, and the nature of the artery involvement, as listed below:

• Obstructive coronary artery disease: It occurs when plaque accumulates in the coronary arteries, medically called atherosclerosis, narrowing the arteries that supply blood to the heart, progressively restricting blood flow and oxygen if the blockage becomes severe, leading to a heart attack. 

• Non-obstructive coronary artery disease: It is defined as arterial hardening caused by the accumulation of plaque that remains unblocked and does not severely restrict blood flow or develop angina symptoms. 

• Microvascular coronary artery disease: Coronary microvascular disease (MVD) is a cardiac condition affecting small arteries that branch from the larger coronary arteries. It causes inner wall damage and spasms and restricts blood flow to the heart muscle. Unlike other types of coronary artery disease, MVD does not include plaque accumulation, although it may still cause cardiac problems.
  

Coronary artery disease classification

Coronary artery disease is classified into different types based on symptoms, ECG abnormalities, and the presence or absence of myocardial injury. This classification helps in evaluating the severity of CAD, predicting patient outcomes, and providing appropriate treatment strategies. The common classification includes.

Stable ischemic heart disease (SIHD): It is a chronic disorder in which the heart's oxygen supply and demand are out of balance.

Acute coronary syndrome: It refers to a group of disorders in which the blood flow to the heart muscle is suddenly stopped or severely reduced. When blood does not flow to the heart muscles, they can become damaged. Acute coronary syndromes (ACS) include heart attacks, also known as myocardial infarction and unstable angina.



• ST-elevation myocardial infarction (STEMI): It is a severe type of heart attack that occurs when a coronary artery is completely blocked.
• Non-ST elevation myocardial infarction (NSTEMI): It is a type of heart attack involving the blockage of one of the coronary arteries, which decreases blood supply to the heart muscles.
• Unstable angina: It occurs when there is insufficient blood and oxygen delivered to the heart muscles, leading to chest pain.
  

Coronary artery disease causes

Understanding the etiology of coronary artery disease (CAD) is essential for its prevention, early detection, and management. The leading causes are listed below:

Common cause of coronary artery disease

• Arteriosclerosis: It is characterised by the accumulation of plaque in arteries, a combination of cholesterol, fatty substances, calcium, cellular debris, fibrous tissue, and inflammatory cells. The most common cause of coronary artery disease is progressive hardening and narrowing of the arteries that transport blood to heart muscles. This lowers or blocks blood flow to the heart muscle and prevents the heart from receiving adequate oxygen-rich blood.



Less cause of coronary artery disease

• Coronary artery spasm: Vascular endothelial dysfunction refers to problems in the inner lining (endothelium) of blood vessels. The endothelium is responsible for healthy blood flow, regulating blood pressure, and preventing blood clots. When this lining does not work properly, it can promote atherosclerosis, leading to coronary artery spasm.

Rare causes of coronary artery disease

• Coronary artery embolism: In this condition, a clot or other material (like fat or air) travels through the bloodstream and blocks a coronary artery. This can stop blood flow to the heart.

• Coronary artery dissection: In this condition, the inner layers of a coronary artery tear, creating a gap that reduces blood flow to the heart.

• Coronary artery aneurysm: This refers to an abnormal bulging or ballooning of the artery wall. It can occur in various conditions, such as Kawasaki disease, a rare childhood illness.

• Vasculitis (Inflammation of the blood vessel): It is characterised by inflammation in the larger arteries, including the aorta and its branches, which supply blood to the heart of the blood vessels.
  

Coronary artery disease symptoms

Some people may not experience any signs and symptoms of coronary artery disease until they are about to experience a serious cardiac event, such as a heart attack or heart failure. However as plaque accumulates in the arteries, they may experience the following coronary artery disease (CAD) symptoms:

• Chest pain or discomfort (angina)
• Pain that spreads to shoulders, arms, neck, jaw and back
• Shortness of breath with activity 
• Cold sweats
• Dizziness
• Light-headedness (a feeling of imbalance)
• Nausea or a feeling of indigestion
• Weakness 

Symptoms of coronary artery disease in women 

Women are less likely than men to experience chest pain; instead, they are more prone to experience signs and symptoms of coronary artery disease (CAD), such as:



Pressure or tightness in the chest

Dizziness 

Nausea 

Stomach pain 

Extreme tiredness

Coronary artery disease risk factors

The risk of coronary heart disease rises with the severity and number of risk factors present. Coronary artery disease risk factors are categorized into modifiable and non-modifiable risk factors that contribute to coronary artery disease, such as:

Modifiable risk factors for coronary artery disease

Modifiable risk factors that can be changed or controlled through lifestyle changes or treatment include:

• Smoking: Smoking can cause coronary heart disease (CHD) by damaging blood vessels, which leads to an increased risk of plaque buildup in the coronary arteries, narrowing and restricting blood flow and oxygen to the body.
• Unhealthy diet: An unhealthy diet can lead to overweight or obesity, raise blood cholesterol levels, and cause plaque buildup in the heart’s arteries, leading to atherosclerosis, which restricts or blocks blood flow.
• Physical inactivity: Physical inactivity contributes to coronary artery disease (CAD) by slowing blood circulation, affecting cholesterol levels by lowering "good" HDL cholesterol, raising "bad" LDL cholesterol, and increasing blood pressure, which puts additional strain on the heart. All of these factors narrow the arteries and reduce blood flow to the heart.
• Obesity or overweight: Obesity or being overweight contribute to coronary heart disease by promoting the buildup of fatty plaques in the coronary arteries, which narrow the arteries and restrict blood flow to the heart.
• Stress: Stress can lead to the tightening of arteries, which may indirectly increase the risk of coronary heart disease by encouraging unhealthy habits, such as smoking or eating high-fat foods heavy and added sugar.
• Poor sleep habits: Getting up frequently at night may increase the chance of developing coronary heart disease because, during sleep, the heart works less. Hence, waking up suddenly may cause a significant increase in blood pressure and heart rate, which is associated with angina. 

Medical conditions that contribute to CAD

• High blood pressure: High blood pressure (hypertension) strains the heart and increases the risk of CHD.
• High cholesterol: Cholesterol is produced by the liver from saturated fats in the diet which is necessary for healthy cells but high levels (too much) of cholesterol in the blood can contribute to CHD.
• Diabetes: A high blood sugar levels or diabetes causes coronary artery disease by thickening the lining of blood arteries, restricting blood flow.
• Obstructive sleep apnea (OSA): In OSA, low oxygen levels during sleep may damage the heart and blood vessels. When oxygen levels decline, the body signals the heart to pump faster which raises blood pressure.
• Chronic kidney disease (CKD): CKD leads to inflammation and contributes to various harmful changes in the cardiovascular system. It leads to the development of atherosclerotic lesions (plaque buildup in the arteries), and vascular calcification (hardening of the blood vessels due to calcium accumulation), causing CAD.

Non-modifiable risk factors for coronary artery disease

The non-modifiable risk factors for CAD are those that cannot be changed or prevented. They contain:

• Age: As people age, their arteries gradually stiffen and become more prone to plaque accumulation, which can cause coronary heart disease (CHD).
• Gender: Gender is an important risk factor for CAD because men develop the condition at a younger age, whereas women's higher HDL cholesterol levels initially provide protection, but this benefit decreases after menopause, increasing the risk of CHD.
• Family history: A family history of premature coronary heart disease in first-degree relatives (parents or siblings) indicates that the individual may have a higher genetic risk at an early age, contributing to a 50% higher lifetime risk of developing the condition.
  

Complications of coronary artery disease

Coronary artery disease can trigger severe, life-threatening complications. The key complications of coronary artery disease (CAD) are listed below:

• Heart failure: Progressive CAD can gradually weaken the heart muscle. This may result in heart failure, a dangerous condition in which the heart doesn't pump enough blood to the body. "Heart failure" does not mean the heart has stopped, but it is a serious condition that requires medical care.

• Arrhythmia (irregular heartbeat): CAD reduces the heart's oxygen supply, causing the heart muscles to weaken or become damaged, disturbing electrical signals and leading to an irregular heartbeat or arrhythmia.

• Heart attacks: CAD narrows the coronary arteries due to plaque accumulation, which reduces blood flow to the heart and if the plaque ruptures, it forms blood clots, completely blocking the blood flow in the artery, leading to heart attack caused by coronary artery disease.

• Ventricular tachycardia (severe arrhythmia): CAD lowers blood flow to the heart and damages the heart muscle, disrupting the heart's regular electrical signals.

• Sudden cardiac death: CAD causes sudden cardiac death (a condition in which the heart suddenly stops beating), primarily by plaque rupture and the development of severe arrhythmias that impair the heart's capacity to pump blood adequately.
  

Coronary artery disease diagnosis

To diagnose coronary artery disease (CAD), the cardiologist reviews the medical history, assesses the symptoms and risk factors, and advises certain laboratory, imaging and diagnostic procedures, including:

• Medical history
• Personal health history
• Family medical history
• Patient symptoms 
• Physical Examination

Coronary artery disease diagnostic tests

If symptoms or a family history of coronary heart disease are present, the healthcare professional (cardiologist) may recommend the following coronary artery disease diagnostic tests, which include:



• Blood tests
• Electrocardiogram (ECG or EKG)
• Coronary calcium scan
• Stress test
• Cardiac magnetic resonance imaging (MRI)
• Cardiac positron emission tomography (PET) scan
• Invasive coronary angiography
• Echocardiography
• Coronary CT angiography
  

Coronary artery disease treatment

Coronary artery disease treatment focuses on controlling symptoms, restoring heart function, preventing further progression of the disease, and minimizing complications. The coronary artery disease treatment options include:

• Lifestyle modifications
• Medical management
• Surgical management

Coronary artery disease lifestyle changes

Adopting heart healthy habits can help manage the disease, prevent its progression, and improve overall heart health. Key lifestyle modifications for coronary artery disease include:

• Choosing heart-healthy foods
• Being physically active
• Quitting smoking
• Getting enough good-quality sleep
• Aiming for a healthy weight
• Controlling blood sugar
• Managing stress

Medical treatment for coronary artery disease

Coronary artery disease drug treatment can reduce or prevent chest discomfort and treat other medical issues. The drugs used in the treatment of coronary artery disease are listed below:

• Blood-thinning medicines
• Statins
• Beta-blockers
• Vasodilators 
• Angiotensin-converting enzyme (ACE) inhibitors
• Angiotensin-2 receptor blockers (ARBs) 
• Calcium channel blockers
• Diuretics

Surgical management of coronary artery disease 

Coronary artery disease surgery is an essential treatment option for individuals with advanced or severe coronary artery disease (CAD) when lifestyle changes and medications are insufficient to treat the condition. Key surgical procedures include:

• Angioplasty for Coronary artery disease 
• Coronary artery bypass graft
• Heart transplant
  

Coronary artery disease prevention

Coronary artery disease (CAD) prevention focuses on lowering risk factors and adopting healthy habits to maintain a healthy heart. Some of the important measures for preventing coronary artery disease are listed below:

• Quitting smoking: To prevent CAD, the most important thing to do is to quit smoking. People who quit smoking have a 50% lower risk of getting coronary artery disease than those who continue to smoke. It makes no difference how long someone smoked before they quit, but quitting decreases the chance of death after coronary artery bypass surgery or a heart attack. It is recommended to avoid second-hand smoke.

• Eating a healthy, balanced diet: A low-fat, high-fiber diet including vegetables, fresh fruits (at least five portions per day), and whole grains can help to reduce the risk of coronary artery disease. Salt intake should be restricted to no more than 6g (which is around one teaspoonful) each day, as too much salt can raise blood pressure. 

• Being physically active: People engaged in physical activities are less prone to develop coronary artery disease and high blood pressure. Exercises that develop endurance (aerobic exercise like brisk walking, bicycling, and jogging) or muscle strength can help prevent coronary heart disease. Even walking for 30 minutes a day can be beneficial.

• Managing obesity: Obesity can be managed by changing diet and increasing physical exercise. Losing just 10 to 20 pounds (4½ to 9 kg) can lower the risk of coronary artery disease.

• Controlling high blood pressure: Lowering high blood pressure decreases the risk of coronary artery disease. Treatment for high blood pressure begins with changes in lifestyle, such as eating a low-salt diet, reducing weight, and increasing physical activity. Medication therapy may also be recommended.

• Controlling high cholesterol levels: Eating a low-fat diet, exercising, stopping smoking, and taking medications that reduce lipids all help to lower high total and LDL (bad) cholesterol levels. These changes are helpful for individuals who have additional risk factors such as obesity, high blood pressure, smoking, and physical inactivity. 

• Reducing alcohol: It is important to avoid consuming large amounts of alcohol in a short period of time, as it raises the risk of heart disease, and it's crucial to limit alcohol intake. 
  

Difference between coronary artery disease and heart disease

Coronary artery disease vs heart disease

Coronary artery disease is a specific condition that falls under the broad-term heart disease. These terms are also interchangeable because heart disease is also called CAD since coronary artery disease is the most common cause of heart-related problems. Some of the differences are listed below:

Difference between Acute coronary syndrome and Coronary artery disease

Acute coronary syndrome vs coronary artery disease

Acute coronary syndrome (ACS) and coronary artery disease (CAD) are interconnected terms that refer to diminished blood flow to the heart muscle. Below are some key differences between them: