Coronary Artery Disease on the NCLEX: Angina to Infarction
Coronary artery disease is a supply problem: narrowed vessels cannot deliver enough oxygen when the heart asks for more. Troponin is what separates unstable angina from infarction, nitroglycerin is the most-tested drug, and the interaction never to miss is nitroglycerin with a phosphodiesterase-5 inhibitor such as sildenafil, which causes profound, refractory hypotension.
Coronary artery disease is a supply problem: narrowed vessels cannot deliver enough oxygen when the heart asks for more. Everything the NCLEX tests follows from that — the risk factors that narrow vessels, the drugs that widen them or reduce demand, and the point at which reduced supply becomes dead muscle.
Step 1 — Risk factors, split the way the exam splits them
| Modifiable — teaching targets | Non-modifiable |
|---|---|
| Smoking (the single biggest one you can change), hypertension, high LDL, diabetes, obesity, inactivity, stress | Age, male sex, family history, ethnicity, postmenopausal status |
Teaching questions almost always target a modifiable factor, and smoking cessation is the highest-yield answer of them all.
Step 2 — Angina versus infarction
| Stable angina | Unstable angina | Myocardial infarction | |
|---|---|---|---|
| Trigger | Predictable — exertion, cold, heavy meal, stress | At rest, or worse than usual | Often at rest |
| Relief | Rest or nitroglycerin relieves it | Poorly relieved | Not relieved |
| Duration | Under 15 minutes | Longer | Over 30 minutes |
| Troponin | Normal | Normal | Rises |
| Muscle | Ischaemic, still alive | Ischaemic, at risk | Dying |
Troponin is what separates unstable angina from infarction. It is the most specific cardiac marker, rises within about 3 hours, and stays elevated for up to two weeks — which is why it can diagnose an MI that happened days ago.
The presentations that get missed
Women, older adults and people with diabetes often present atypically: fatigue, shortness of breath, nausea, indigestion, jaw or back pain — sometimes no chest pain at all. Diabetic neuropathy can produce a silent MI. If a stem gives you an older diabetic woman with unexplained fatigue and nausea, cardiac is on the list.
Step 3 — Nitroglycerin, in detail
This is the most-tested drug in the topic. The rules:
| Rule | Detail |
|---|---|
| How to take it | Sit or lie down first — it drops blood pressure and causes fainting. Sublingual, do not swallow or chew |
| How often | One dose, wait 5 minutes, up to 3 doses. Pain persisting after three doses is an emergency — call emergency services |
| Expected effects | Headache and flushing are expected, not reasons to stop. A tingling under the tongue suggests the tablet is potent |
| Storage | Original dark glass bottle, tightly capped, away from heat and light. Replace roughly every 6 months |
| Hold if | Systolic under 90, or heart rate outside parameters |
| Patches | Rotate sites, remove the old one first, and allow a nitrate-free interval (usually overnight) to prevent tolerance |
The interaction that kills: nitroglycerin with a phosphodiesterase-5 inhibitor — sildenafil, tadalafil, vardenafil — causes profound, refractory hypotension. Ask about them. This appears on the exam and it appears in real emergency departments.
Step 4 — Acute coronary syndrome, in order
The traditional mnemonic is MONA — Morphine, Oxygen, Nitroglycerin, Aspirin — but that is not the order things are done. In practice:
- Aspirin, chewed, early — it is the intervention with the clearest mortality benefit.
- 12-lead ECG within 10 minutes. This decides whether the client goes to the cath lab.
- Oxygen only if hypoxic — routine oxygen in a non-hypoxic client is no longer recommended.
- Nitroglycerin, watching the blood pressure.
- Morphine for pain not relieved by nitrates. It reduces pain, anxiety and preload.
- Troponin, then reperfusion — PCI within 90 minutes where available, otherwise thrombolytics.
Ongoing medication after an event, and why each: aspirin and a second antiplatelet to prevent clot, a beta blocker to reduce workload, an ACE inhibitor to prevent remodelling, and a statin regardless of the cholesterol number.
Step 5 — Cardiac catheterisation care
| Before | After |
|---|---|
| Ask about iodine and shellfish allergy — the contrast is iodine-based Check renal function; contrast is nephrotoxic Hold metformin — usually 48 hours, because of lactic acidosis risk with contrast Warn about a warm flush and a fluttering feeling — expected, not an emergency | Bed rest, affected leg straight, head of bed low Check the site for bleeding or haematoma Check distal pulses, colour, warmth and sensation — compare both sides Push fluids to clear the contrast Report bleeding, a cool pale foot, absent pulse, or new back pain |
A cool, pale foot with no palpable pulse after a femoral cath is an arterial occlusion — an emergency, and the highest-priority post-procedure finding.
Teaching for living with it
Cardiac rehabilitation, a Mediterranean or DASH-style diet, activity built up gradually, and specific guidance about sex, driving and returning to work — clients ask and rarely get told. Report chest pain not relieved by three nitroglycerin doses, new shortness of breath, weight gain of 2 to 3 lb in a day, or fainting.
NCLEX tip: If pain goes away with rest or nitroglycerin and the troponin is normal, it is angina. If it persists through three doses, it is an emergency and the answer is never a fourth tablet. And always ask about erectile-dysfunction drugs before giving a nitrate — that combination is fatal.
Frequently asked questions
Common follow-up questions on Body Systems & Clinical Content.
How does troponin distinguish angina from a myocardial infarction?
Troponin is normal in both stable and unstable angina but rises in a myocardial infarction, so it is what separates unstable angina from infarction. It is the most specific cardiac marker, rises within about 3 hours, and stays elevated for up to two weeks, which is why it can diagnose an MI that happened days ago.
What are the rules for taking nitroglycerin?
Sit or lie down first, because it drops blood pressure and causes fainting, and take it sublingually without swallowing or chewing. Take one dose, wait 5 minutes, up to 3 doses; pain persisting after three doses is an emergency requiring emergency services. Headache and flushing are expected effects, and the tablets are stored in the original dark glass bottle away from heat and light.
What drug interaction with nitroglycerin can kill a client?
Nitroglycerin with a phosphodiesterase-5 inhibitor (sildenafil, tadalafil or vardenafil) causes profound, refractory hypotension. Always ask about these erectile-dysfunction drugs before giving a nitrate. This appears on the exam and in real emergency departments.
How do women, older adults and diabetics present?
They often present atypically with fatigue, shortness of breath, nausea, indigestion, jaw or back pain, or sometimes no chest pain at all. Diabetic neuropathy can produce a silent MI. If a stem gives an older diabetic woman with unexplained fatigue and nausea, cardiac is on the list.
What is the cardiac catheterisation aftercare?
Keep the client on bed rest with the affected leg straight and the head of bed low, check the site for bleeding or haematoma, and check distal pulses, colour, warmth and sensation, comparing both sides. Push fluids to clear the contrast. A cool, pale foot with no palpable pulse after a femoral cath is an arterial occlusion, an emergency and the highest-priority post-procedure finding.
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