What causes cardiovascular disease

Diseases affecting the heart or blood vessels are collectively referred to as cardiovascular diseases (CVD). They account for 32% of all global deaths, and of these 85% are due to heart attack and stroke, making it the leading cause of death globally.

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However, it is interesting to know that most of these deaths are preventable. Small lifestyle changes make a big difference in protecting our heart health.

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In this blog, Gauze discusses the causes of cardiovascular diseases and their underlying pathophysiology.

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What is cardiovascular disease?

It is a group of diseases that affect the heart and blood vessels, for which a patient may be symptomatic (experience physical symptoms) or asymptomatic (experience no symptoms).

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They may be caused by

• Narrowing of the blood vessels in the heart
• Congenital (at birth) heart and blood vessel problems
• Improperly working heart valves
• Irregular heart rhythms

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Types of cardiovascular disease

• Heart disease

Coronary artery disease, or ischemic heart disease, is the most common heart disease. It occurs when the coronary arteries are unable to supply blood to the heart muscles.

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• Heart attack

Heart attacks, also known as myocardial infarction, occur when a blood clot blocks the flow of blood to the heart. Deprived of oxygen and nutrients, the heart muscle gets damaged.

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• Stroke

A stroke occurs when the blood supply to the brain gets blocked. The blockage cuts off oxygen and nutrients to the cells, which damages brain cells. Stroke may be caused by a

• A blood clot in the brain artery  
• Bursting of a blood vessel in the brain

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• Other conditions 

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Heart related

• Arrhythmia, or irregular or abnormal heartbeat
• Cardiomyopathy is a heart muscle disease
• Congenital heart disease, which is present since birth
• Heart valve disease
• Pericarditis is inflammation of the heart
• Rheumatic heart disease damages the heart's muscles or valves due to bacterial infections caused by Streptococcus.
• Heart failure occurs when the heart doesn’t pump blood as it should

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Vessel related

• Deep vein thrombosis and pulmonary embolism are blood clots that break loose and travel to the heart or lungs
  

• Peripheral vascular disease is a condition that affects the blood vessels supplying the arms and legs.
• Cerebrovascular disease is a condition that affects the blood vessels supplying the brain.

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Risk factors of cardiovascular disease

A healthy diet, regular physical activity, and avoiding harmful habits are essential for maintaining a healthy heart. The risk factors of cardiovascular disease are

• High blood pressure
• High cholesterol
• Obesity
• Metabolic disorders like diabetes

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Factors contributing to heart disease development

• Not eating a healthy and balanced diet
• Leading a sedentary life, doing no exercise
• Not maintaining a healthy body weight
• Consuming tobacco and alcohol
• Leading a stressful life
• Ignoring health screenings 
• Missing prescribed medications

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Symptoms of cardiovascular disease 

• Chest pain, tightness, or discomfort
• Pain radiating to arms, neck, shoulders, jaw, and back
• Numbness in legs or arms
• Changes in heart rhythm
• Shortness of breath
• Getting tired during exercise or activity
• Dizziness, Lightheadedness, or fainting
• Swelling of hands, legs, ankles, or feet

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What causes cardiovascular diseases?

Now that we understand what cardiovascular disease is. We must try to understand how the disease is caused.

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What is atherosclerosis?

The major cause of cardiovascular disease is atherosclerosis. Atherosclerosis occurs when

• Plaque (a sticky substance made of fat, cholesterol, calcium, and other substances present in blood) builds up gradually inside the arteries.
• When arteries harden due to the deposition of plaque.

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The buildup of plaque narrows the arteries, reducing blood flow until you develop symptoms like a heart attack or stroke.

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The hardening of arteries is usually a silent process in the early stages. Still, as the plaque grows, the diameter of the arteries continues to reduce, and blood can no longer pass through them. The constant force of blood flow leads to the rupture of plaque, causing a blood clot to form.

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Stages of atherosclerosis

Atherosclerosis develops in stages over a long period

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• Endothelial damage and immune response

The inner lining of a blood vessel (endothelium) is damaged by high blood pressure, smoking, or high cholesterol; the injury attracts white blood cells. These cells move to the site of injury, causing local inflammation.

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• Fatty streak formation

A yellow line or patch inside the artery is the first visible sign of atherosclerosis. 

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It forms when white blood cells ingest cholesterol particles and turn them into foam cells. 

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White blood cells consume cholesterol to break it down, and patches of foam cells accumulate at the site of blood vessel damage. 

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The foam cell’s continued activity further damages the inner lining of the blood vessels (or endothelium).

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• Plaque growth

Dead foam cells and debris continue to accumulate, and large pieces of plaque form within the artery wall. 

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Smooth muscle cells migrate to the area, forming a fibrous cap over the plaque, creating a protective barrier. 

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As plaque grows, it reduces the lumen (the hollow interior) of the blood vessel, thereby reducing blood flow and oxygen supply to the tissues.

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• Plaque rupture

Gradually, the fibrous cap ruptures, exposing plaque contents to the bloodstream. 

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Another possibility is that the cap remains intact. Still, the surrounding endothelial cells become damaged, leading to the formation of a clot that suddenly blocks blood flow and causes a heart attack or stroke.

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Complications of atherosclerosis

Atherosclerosis restricts blood flow to various parts of the body and impairs the heart's function. Its complications are

• Carotid artery disease
• Coronary artery disease
• Stroke
• Heart attack
• Peripheral artery disease
• Transient ischemic attack
• Chronic kidney disease

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Early diagnosis and treatment help to avoid or delay complications

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Conclusion

Cardiovascular diseases build up silently and slowly and are usually associated with life-threatening events like a heart attack or stroke. These diseases can be prevented by managing blood pressure, quitting smoking, eating a heart-healthy diet, staying physically active, and controlling cholesterol levels. These steps prevent complications and provide long-term health.