Differences Between Stable and Unstable Angina

Angina is chest pain caused by myocardial ischaemia, typically due to coronary artery disease. Recognising the differences between stable and unstable angina is crucial for risk stratification and management.

Here’s a table comparing Stable Angina and Unstable Angina:

Feature	Stable Angina	Unstable Angina
Symptoms	Predictable chest discomfort, triggered by exertion or stress, relieved by rest or GTN	New-onset angina, angina at rest, or worsening of previous angina
Pathophysiology	Fixed atherosclerotic plaque reducing perfusion during increased demand	Plaque rupture and thrombosis with partial coronary occlusion
Duration	Brief (<10 minutes), improves with rest	More prolonged or unpredictable, not fully relieved by GTN
ECG and Troponin	Usually normal at rest; no troponin rise	May show ST changes; troponin normal (key difference from NSTEMI)
Risk	Lower short-term risk of myocardial infarction	High risk of progression to myocardial infarction
Management	Outpatient referral, lifestyle advice, antianginals, aspirin, statins	Emergency referral, hospital admission, DAPT, anticoagulation, cardiology input

Clinical Implication

Unstable angina is a medical emergency requiring urgent assessment and treatment, whereas stable angina allows for planned outpatient management.

Reference: NICE Clinical Guideline [CG95] – Chest Pain of Recent Onset.