Key Facts

Stable angina is characterised by predictable, exertion-related chest discomfort caused by fixed coronary artery atherosclerotic stenosis causing myocardial ischaemia. It is relieved by rest or sublingual GTN.

Epidemiology

• Prevalence: ~2 million people in the UK
• More common in men; female incidence rises post-menopause
• Incidence increases with age: ~5-7% in those aged 65-74
• Risk factors: smoking, hypertension, diabetes, hyperlipidaemia, family history, obesity, sedentary lifestyle

Aetiology

• Atherosclerotic coronary artery disease (>95% of cases)
• Fixed stenosis typically >70% luminal narrowing to cause exertional symptoms
• Rarely: coronary artery spasm (Prinzmetal/variant angina), microvascular angina (cardiac syndrome X), aortic stenosis, hypertrophic cardiomyopathy

Pathophysiology

• Atherosclerotic plaque reduces coronary blood flow reserve
• At rest, coronary flow is adequate; during exertion/stress, myocardial oxygen demand exceeds supply
• Ischaemia leads to anaerobic metabolism, lactate accumulation, and chest pain
• Supply-demand mismatch is predictable and reproducible

Typical Presentation

• Central/left-sided chest pain or tightness, often described as heaviness, squeezing, or pressure
• Provoked by exertion, emotional stress, cold weather, heavy meals
• Duration: typically 2-10 minutes
• Relieved by rest (within 5 minutes) or sublingual GTN (within 1-3 minutes)
• May radiate to left arm, jaw, neck, back, or epigastrium

Atypical Presentations

• More common in women, elderly, and diabetic patients
• Breathlessness as angina equivalent
• Epigastric discomfort mimicking dyspepsia
• Fatigue or exercise intolerance

CCS Classification

• Class I: angina only with strenuous exertion
• Class II: slight limitation of ordinary activity
• Class III: marked limitation of ordinary activity
• Class IV: angina at rest or with any physical activity

Red Flags

• Pain at rest or with minimal exertion (unstable angina)
• Increasing frequency or severity (crescendo pattern)
• New-onset angina
• Pain lasting >15 minutes not relieved by GTN
• Associated haemodynamic instability

Bedside

• ECG: may be normal at rest; ST depression or T-wave inversion during pain
• BMI, waist circumference: cardiovascular risk assessment

Bloods

• FBC: anaemia (exacerbates angina)
• U&Es: renal function (before ACEi, contrast)
• Lipid profile: dyslipidaemia
• HbA1c/fasting glucose: diabetes
• TFTs: thyroid dysfunction
• LFTs: baseline before statin
• Troponin: should be NEGATIVE in stable angina (if positive, consider ACS)

Imaging

• CT coronary angiography (CTCA): NICE NG106 first-line for chest pain of recent onset
• Invasive coronary angiography: gold standard; if CTCA inconclusive or high-risk features
• Functional imaging (if known CAD): stress echocardiography, myocardial perfusion scintigraphy (MPS), stress cardiac MRI
• Echocardiography: LV function, regional wall motion abnormalities, valve disease

Special Tests

• Exercise ECG: no longer recommended as first-line by NICE for diagnosis (low sensitivity ~65%)
• QRISK3: cardiovascular risk stratification
• Fractional flow reserve (FFR): during angiography to assess haemodynamic significance of stenosis

Non-pharmacological

• Cardiac rehabilitation and structured exercise programme
• Smoking cessation (refer to NHS Stop Smoking service)
• Dietary modification: Mediterranean diet, reduce saturated fat
• Weight management
• Limit alcohol (≤14 units/week)

Pharmacological

Symptom relief:

• Sublingual GTN spray: 400mcg PRN (1-2 puffs under tongue; can repeat after 5 minutes; call 999 if pain persists after 3rd dose)
• First-line anti-anginal: beta-blocker (bisoprolol 2.5-10mg OD or atenolol 50-100mg OD) OR CCB (amlodipine 5-10mg OD)
• If monotherapy insufficient: combine beta-blocker + dihydropyridine CCB
• Alternatives: long-acting nitrate (isosorbide mononitrate 30-120mg MR OD — ensure nitrate-free interval), nicorandil 10-30mg BD, ivabradine 2.5-7.5mg BD (if sinus rhythm, HR >70), ranolazine 375-750mg BD

Secondary prevention:

• Aspirin 75mg OD (or clopidogrel 75mg if aspirin intolerant)
• Atorvastatin 80mg OD (high-intensity statin)
• ACE inhibitor (ramipril 1.25-10mg OD) if diabetes, hypertension, CKD, or LV dysfunction
• Optimal BP control: target <140/90 mmHg

Landmark trials:

• ISCHEMIA: no benefit of routine invasive strategy over OMT for stable CAD (except for symptom relief)
• COURAGE: PCI + OMT did not reduce death/MI vs OMT alone in stable CAD
• ORBITA: PCI did not improve exercise time vs sham procedure in single-vessel stable angina

Surgical/Interventional

• PCI (percutaneous coronary intervention): for refractory symptoms despite OMT or high-risk anatomy
• CABG (coronary artery bypass grafting): indicated for left main stem disease, triple-vessel disease (especially with impaired LV function or diabetes)
• Decision made via Heart Team MDT discussion

Referral Criteria

• Rapid access chest pain clinic for new-onset suspected angina
• Cardiology referral for refractory symptoms on maximal medical therapy
• Urgent referral if features suggestive of ACS

• Annual mortality: ~1-3% for stable angina on optimal medical therapy
• Annual MI rate: ~1-2%
• Prognosis worsened by: multivessel disease, impaired LV function, diabetes, left main stem disease
• CABG improves survival in left main stem and triple-vessel disease
• PCI improves symptoms but not mortality in most stable CAD
• 5-year mortality after CABG: ~5-10%; after PCI: similar but higher revascularisation rates

CCS Angina Classification

Anti-Anginal Drug Summary