Coronary artery stenosis refers to the narrowing of coronary arteries, which supply oxygen-rich blood to the heart muscle. This narrowing is typically due to atherosclerosis, a buildup of plaque composed of cholesterol, calcium, and cellular waste. Over time, this restricts blood flow to the heart, leading to conditions like angina, myocardial infarction (heart attack), or even sudden cardiac death.
This article provides an in-depth overview of the causes, symptoms, diagnosis, and management of coronary artery stenosis, optimized for both exam preparation (NEET PG, USMLE, INI-CET) and clinical understanding.
What is Coronary Artery Stenosis?
Coronary artery stenosis is the narrowing or partial obstruction of the coronary arteries. It is most often caused by atherosclerotic plaque, leading to a reduction in coronary blood flow, especially during increased demand such as exercise or stress.
Pathophysiology:
- Endothelial injury due to smoking, hypertension, diabetes
- Lipid infiltration into vessel wall
- Inflammatory response leads to fibrous cap formation
- Plaque growth narrows the lumen of the artery
- Ischemia occurs when oxygen demand exceeds supply
Symptoms of Coronary Artery Stenosis
Based on the visual, the key clinical features include:
| Symptom | Description |
|---|---|
| Asymptomatic | Many patients remain symptom-free for years until a major event occurs |
| Chest pain | Classic angina due to reduced oxygen supply to myocardium |
| Syncope | Loss of consciousness due to decreased cardiac output |
| Dyspnoea | Shortness of breath, especially on exertion |
| Palpitations | Awareness of heartbeats, often due to ischemic arrhythmias |
| Cough (haemoptysis) | May indicate pulmonary edema or heart failure |
| Excessive fatigue | Common but underappreciated symptom, especially in women |
Stages and Classification
Coronary stenosis can be classified based on the percentage of artery narrowing:
| Degree of Stenosis | Lumen Narrowing | Clinical Impact |
|---|---|---|
| Mild | <50% | Often asymptomatic |
| Moderate | 50–70% | Angina with exertion |
| Severe | >70% | Angina at rest or during minimal activity |
| Critical | >90% | High risk of myocardial infarction |
Risk Factors
Understanding the underlying risk factors is critical to prevention and early detection:
1. Modifiable Risk Factors:
- Hypertension
- Hyperlipidemia
- Diabetes Mellitus
- Smoking
- Sedentary lifestyle
- Obesity
- Stress
- Age >45 in men, >55 in women
- Male gender
- Family history of premature coronary artery disease
Diagnosis of Coronary Artery Stenosis
1. Electrocardiogram (ECG)
- May show ST depression or T wave inversion
- Stress ECG reveals ischemic changes with exertion
2. Echocardiography
- Assesses heart wall motion abnormalities
- Useful in evaluating left ventricular function
3. Stress Testing
- Treadmill test or stress echocardiogram
- Helps provoke symptoms and detect ischemia
4. Coronary Angiography
- Gold standard
- Visualizes the degree and exact location of stenosis
- Guides interventional or surgical treatment
5. CT Coronary Angiography
- Non-invasive imaging
- Useful in low-risk symptomatic patients
Clinical Case Example
A 58-year-old male with a history of diabetes and smoking presents with:
- Exertional chest discomfort radiating to the left arm
- Shortness of breath after climbing stairs
- Recent episodes of palpitations and fatigue
Investigations:
- ECG: ST depression in anterior leads
- Troponin: Negative
- Coronary angiogram: 80% stenosis in LAD artery
Diagnosis:
- Severe coronary artery stenosis with stable angina
Management Strategies
Management of coronary artery stenosis includes both medical therapy and revascularization when necessary.
A. Lifestyle Modifications
- Smoking cessation
- Weight reduction
- Dietary changes (Mediterranean diet)
- Regular physical activity
- Stress management
B. Pharmacological Therapy
| Drug Class | Examples | Purpose |
|---|---|---|
| Antiplatelets | Aspirin, Clopidogrel | Prevent clot formation |
| Beta-blockers | Metoprolol, Atenolol | Reduce heart rate and oxygen demand |
| Nitrates | Nitroglycerin | Relieve angina |
| Statins | Atorvastatin, Rosuvastatin | Lower LDL cholesterol |
| ACE inhibitors | Ramipril, Lisinopril | Cardioprotective in diabetics |
| Calcium channel blockers | Amlodipine, Verapamil | Alternative to beta-blockers in angina |
C. Interventional and Surgical Treatment
1. Percutaneous Coronary Intervention (PCI)
- Balloon angioplasty followed by stent placement
- Drug-eluting stents (DES) preferred for long-term patency
2. Coronary Artery Bypass Grafting (CABG)
Indicated in:
- Triple vessel disease
- Left main coronary artery disease
- Failed angioplasty
Prognosis
Prognosis depends on:
- Severity of stenosis
- Number of vessels involved
- Left ventricular function
- Control of risk factors
Improved outcomes with:
- Early detection
- Lifestyle adherence
- Adherence to medical therapy
- Prompt revascularization
Prevention of Coronary Artery Stenosis
Prevention is better than cure — especially for this silent and progressive condition.
| Preventive Measure | Details |
|---|---|
| Heart-healthy diet | Low saturated fat, high fiber |
| Regular aerobic exercise | At least 150 minutes per week |
| Blood pressure management | Target <130/80 mmHg |
| Diabetes control | HbA1c <7% |
| Smoking cessation | Complete abstinence |
| Lipid profile optimization | LDL <70 mg/dL in high-risk patients |
| Regular check-ups | Especially if family history is positive |
Coronary Artery Stenosis vs. Coronary Artery Disease (CAD)
| Parameter | Coronary Artery Stenosis | Coronary Artery Disease |
|---|---|---|
| Definition | Narrowing of coronary arteries | Broader term including stenosis, MI, angina |
| Cause | Mostly atherosclerosis | Includes thrombosis, emboli, vasospasm |
| Symptoms | May be asymptomatic | Variable - angina, MI, heart failure |
| Diagnostic Gold Standard | Coronary angiography | ECG + Biomarkers + Angiography |
| Treatment | Medical and/or revascularization | Depends on stage of disease |
Frequently Asked Questions (FAQs)
Q1. Can coronary artery stenosis be reversed?
A: Mild to moderate stenosis can improve with aggressive lifestyle changes and statin therapy. Severe narrowing often requires intervention.
Q2. Is coronary stenosis always symptomatic?
A: No. Many cases are asymptomatic until blood flow is severely compromised or during exertion.
Q3. What is the difference between stable and unstable angina?
A: Stable angina occurs with exertion and is relieved by rest; unstable angina occurs at rest and is a medical emergency.
Q4. What is LAD stenosis?
A: LAD (left anterior descending artery) stenosis is a critical blockage as it supplies a major portion of the left ventricle. It is often called the "widow-maker."
Q5. Is angioplasty permanent?
A: Angioplasty relieves stenosis, but restenosis can occur. Drug-eluting stents reduce this risk significantly.
Summary Table: At a Glance
| Feature | Description |
|---|---|
| Definition | Narrowing of coronary arteries due to plaque |
| Most common cause | Atherosclerosis |
| Key symptoms | Chest pain, dyspnea, fatigue, palpitations, syncope |
| Gold standard test | Coronary angiography |
| Initial management | Antiplatelets, statins, beta-blockers, nitrates |
| Definitive therapy | PCI (angioplasty) or CABG |
| Prevention | Lifestyle + Risk factor control |
