Coronary Artery Disease and Angina: Stable

Coronary artery disease (CAD) and angina are common cardiac conditions caused by narrowed or blocked coronary arteries that reduce blood flow to the heart. This guide reviews how to distinguish stable from unstable angina, the priority assessments and treatments (including MONA), and the high-yield teaching and NCLEX points nursing students need to know.

Definition

Coronary artery disease and angina are heart conditions caused by narrowed or blocked arteries that reduce blood flow to the heart, leading to chest pain or discomfort and increasing the risk of a heart attack. The chest pain can be either stable angina or unstable angina.

Stable vs Unstable Angina

Feature	Stable Angina	Unstable Angina
Onset	With exertion	At rest or minimal activity
Duration	Brief (3–5 min)	Prolonged (>20 min)
Relief	Rest or NTG works	May not relieve with NTG
Troponin	Normal	Normal (no heart damage)
Risk	Low for heart attack	High for heart attack

Risk Factors

Non-modifiable: age (men >45, women >55), family history, male gender
Modifiable: high blood pressure, high cholesterol, diabetes

Pathophysiology

Plaque builds up in arteries over years from cholesterol and inflammation.
Stable plaque has a thick fibrous cap, small lipid core, and low inflammation, making it less likely to rupture.
Unstable plaque has a thin fibrous cap, large lipid core, and high inflammation, making it prone to rupture.
When a plaque ruptures, it triggers clot (thrombus) formation, which can partially or completely block blood flow.

Stable Angina (The Predictable One)

Chest pain happens with walking, stress, cold, or heavy meals.
Pain is pressure, squeezing, or heaviness in the chest.
May radiate to left arm, jaw, or back.
Lasts 3 to 5 minutes and goes away with rest or nitroglycerin.
This is not a heart attack — no heart damage occurs.

Unstable Angina (The Dangerous One)

This is a medical emergency and can lead to a heart attack.
Pain happens at rest or with very little activity.
Lasts longer than 20 minutes.
Pain may get worse, happen more often, or not go away with nitroglycerin.
Troponin is normal — this is how you know it's not a heart attack.
Three types: rest angina, new angina that limits activity, or worsening angina.

Signs and Symptoms of Angina

Chest pain: pressure, squeezing, or heaviness behind the breastbone
Pain can radiate to left arm, jaw, shoulder, or back
Shortness of breath, sweating, nausea, or dizziness
Women, diabetics, and the elderly may have no chest pain
They may only feel tired, sick to the stomach, or confused
Diabetics can have "silent" angina with no symptoms at all

High-Risk Signs

Pain at rest lasting over 20 minutes
Symptoms getting worse quickly
Signs of heart failure: trouble breathing, crackles in lungs
Low blood pressure or age over 75
ECG changes (ST depression or T-wave inversion)

Diagnostic Tests

ECG: done within 10 minutes; looks for ST changes
Troponin: blood test; normal in angina, high in heart attack
Stress test: exercise while watching ECG; looks for ST changes
Angiogram: dye test to see blockages — gold standard

Emergency Treatment: MONA

Drug	What It Does	When to Hold / Notes
Morphine	Pain relief, calms patient	Hold for low blood pressure
Oxygen	Use only if O₂ low (<90%)	Do not give routinely; hold if oxygen saturation is above 90%
Nitroglycerin	Opens arteries, relieves pain	Hold if BP <90 or PDE5 inhibitors (e.g., Viagra) used within 24–48 hours
Aspirin	Stops clots from growing	Must be chewed for rapid absorption

Aspirin 325 mg must be chewed immediately.
Nitroglycerin under the tongue every 5 minutes × 3 doses.
No nitroglycerin if BP is low or Viagra/Cialis was taken in the last 24–48 hours.
Oxygen only for low oxygen levels.

Nitroglycerin Patient Teaching

Take 1 pill at first sign of chest pain.
Wait 5 minutes; if no relief, take a 2nd pill.
Wait 5 more minutes; if no relief, take a 3rd pill.
If still no relief after 3 pills in 15 minutes, call 911.
Never drive yourself to the hospital.
Sit or lie down after taking to prevent falls.
Store in a dark bottle away from heat; replace every 6–12 months.
Side effects: headache, flushing, dizziness.

Nursing Care

Place patient on heart monitor.
Check vital signs often.
Get ECG within 10 minutes.
Start IV line.
Give aspirin (chewed), nitroglycerin, and morphine as ordered.
Check troponin levels.
Watch for bleeding from blood thinners.
Listen to lungs for crackles (fluid).
Check legs for swelling.
After angiogram, check pulses and bleeding at the catheter site.

Patient Teaching

Take aspirin and blood thinners exactly as ordered; never stop without asking.
Call the doctor for dark stools, coffee-ground vomit, or unusual bruising.
Carry nitroglycerin at all times.
Quit smoking — the first thing a patient can do.
Eat a low-fat, low-salt diet with fruits and vegetables.
Go to cardiac rehab to learn safe exercise.
Know the difference: stable pain is predictable and relieved by rest; unstable pain is at rest and not relieved.
If pain lasts >15 minutes after NTG, call 911.

Common NCLEX Traps

Stable = predictable with exertion; unstable = at rest, unpredictable.
Troponin is normal in unstable angina; high in heart attack.
Women, diabetics, and elderly may have no chest pain.
Oxygen is not routine — only if O₂ is low.
Check BP before nitroglycerin; hold if low.
Aspirin must be chewed.
Unstable angina needs admission; stable angina can go home.

Rapid Summary

Stable angina: predictable chest pain with exertion that resolves with rest or nitroglycerin within 5 minutes; no heart damage.
Unstable angina: warning sign — pain at rest lasting over 20 minutes with normal troponin; high risk for heart attack.
Treatment is MONA: Morphine for pain, Oxygen only if low, Nitroglycerin for chest pain, Aspirin chewed immediately.
Key difference: troponin is normal in unstable angina but high in heart attack; unstable angina means admission to the hospital.

Key Takeaways

Stable angina is predictable, exertional, brief (3–5 min), and relieved by rest or NTG.
Unstable angina occurs at rest, lasts >20 min, may not respond to NTG, and is a medical emergency.
Troponin is normal in both stable and unstable angina — elevation indicates a heart attack, not angina.
Initial treatment follows MONA: chewed aspirin 325 mg, sublingual nitroglycerin q5min × 3, oxygen only if SpO₂ <90%, and morphine for unrelieved pain.
Hold nitroglycerin for SBP <90 or recent PDE5 inhibitor use (Viagra/Cialis within 24–48 hours).
If chest pain is not relieved after 3 NTG doses in 15 minutes, call 911 — do not drive.

Coronary Artery Disease and Angina: Stable vs Unstable