Coronary Artery Disease 

Coronary Artery Disease (CAD) is a cardiovascular disorder in which the coronary arteries, which supply the heart with oxygen and nutrients, become narrowed or blocked by fatty deposits (plaques) on their inner walls. This can cause limited blood flow to the heart muscle (myocardium), which can result in angina (chest pain) and, in severe cases, a heart attack (myocardial infarction). CAD is the leading cause of cardiac dysfunction and death globally.

1.0Structure and Role of Coronary Arteries

The coronary arteries branch from the aorta just after it leaves the left ventricle. They form two major branches:

1. Right Coronary Artery (RCA): Supplies blood to the right atrium, right ventricle, and parts of the conduction system (SA and AV nodes).
2. Left Coronary Artery (LCA): Divides into

• Left Anterior Descending (LAD) artery: Supplies the front wall of the left ventricle.
• Circumflex artery: Supplies the lateral and posterior regions of the heart.

Any obstruction in these arteries disrupts oxygen and nutrient delivery to cardiac tissue, impairing its normal function.

2.0Causes of Coronary Artery Disease

CAD primarily develops due to atherosclerosis, a gradual accumulation of lipid-rich plaques within the arterial walls.
Major causes include:

• High cholesterol levels (especially LDL cholesterol)
• High blood pressure (hypertension)
• Smoking and alcohol consumption
• Obesity and sedentary lifestyle
• Diabetes mellitus
• Genetic predisposition
• Chronic stress
• Unhealthy diet rich in saturated fats and processed foods

Over time, these factors damage the inner lining of arteries (endothelium), allowing plaque formation and vessel narrowing.

3.0Pathophysiology of CAD

1. Endothelial Damage:

• Triggered by high cholesterol, smoking, or hypertension.

2. Atherosclerotic Plaque Formation:

• Lipids, calcium, and white blood cells accumulate beneath the endothelium.
• This leads to arterial thickening and loss of elasticity.

3. Reduced Blood Flow:

• As the lumen narrows, less oxygenated blood reaches cardiac tissue.

4. Ischemia:

• Oxygen deprivation causes chest pain (angina pectoris).

5. Complete Blockage:

• If the plaque ruptures and a clot (thrombus) forms, it can completely block the artery, leading to myocardial infarction (heart attack).

4.0Symptoms of Coronary Artery Disease

CAD often develops silently over years before showing noticeable symptoms. Common signs include:

• Chest pain or discomfort (angina) — typically felt during exertion
• Shortness of breath
• Fatigue or weakness
• Palpitations (irregular heartbeat)
• Dizziness or fainting
• Pain radiating to the left arm, jaw, neck, or back

In some cases, the first sign of CAD may be a sudden heart attack, highlighting its dangerous progression.

5.0Types of Coronary Artery Disease

6.0Risk Factors for Coronary Artery Disease

Risk factors can be categorised as modifiable and non-modifiable:

Modifiable Factors:

• Smoking
• High cholesterol
• High blood pressure
• Obesity
• Lack of physical activity
• Unhealthy diet
• Stress

Non-Modifiable Factors:

• Age (risk increases with age)
• Gender (men are more prone; risk increases in women post-menopause)
• Family history of heart disease
• Genetic factors

7.0Diagnosis of Coronary Artery Disease

Several diagnostic tests are used to evaluate CAD:

1. Electrocardiogram (ECG): Detects abnormal heart rhythms and ischemic changes.
2. Echocardiogram: Uses sound waves to assess heart structure and function.
3. Stress Test: Measures heart performance during physical exertion.
4. Coronary Angiography: Imaging technique using contrast dye to visualize artery blockages.
5. CT Coronary Angiogram: Non-invasive scan to detect plaques and vessel narrowing.
6. Blood Tests: Check for elevated cholesterol, triglycerides, and cardiac enzymes.

8.0Prevention of Coronary Artery Disease

Preventive measures are aimed at reducing modifiable risk factors:

• Keep cholesterol and blood pressure low.
• Follow a heart-healthy diet that includes enough fruits, vegetables, and omega-3 fatty acids.
• Get regular exercise and use that to help you maintain your heart health.
• Don't smoke and limit alcohol.
• Learn ways to manage stress through relaxation and/or meditation.
• Control diabetes and obesity through medical guidance and lifestyle changes.

9.0Treatment of Coronary Artery Disease

The choice of treatment depends on the severity of arterial blockage and symptoms:

1. Medications

• Nitrates (Nitroglycerin): Relieve chest pain by dilating arteries.
• Beta-blockers: Lower heart rate and oxygen demand.
• Calcium channel blockers: Relax blood vessels and improve blood flow.
• Statins: Reduce cholesterol and slow plaque buildup.
• Antiplatelet drugs (Aspirin): Prevent clot formation.

2. Surgical Procedures

• Angioplasty (Percutaneous Coronary Intervention):
  A balloon-tipped catheter widens narrowed arteries, often followed by stent placement.
• Coronary Artery Bypass Grafting (CABG):
  A surgical procedure that creates a bypass around blocked arteries using grafted vessels from other parts of the body.

Both methods restore blood flow to the heart and prevent further ischemic damage.

10.0Complications of Coronary Artery Disease

If untreated, CAD can lead to serious complications such as:

• Heart attack (Myocardial infarction)
• Heart failure (weakened pumping ability)
• Arrhythmias (irregular heartbeats)
• Sudden cardiac arrest

Timely diagnosis and management are critical to prevent these life-threatening conditions.

11.0Coronary Artery Disease Examples

• Atherosclerosis of Left Anterior Descending Artery (LAD): Commonly known as the “widowmaker,” blockage here can cause fatal heart attacks.
• Right Coronary Artery Occlusion: Leads to conduction abnormalities due to SA/AV node ischemia.
• Multi-vessel CAD: Involves blockages in multiple coronary arteries, severely limiting heart function.

These examples highlight how the specific site and extent of arterial blockage determine the severity and prognosis of CAD.