Pathophysiology & epidemiology
- Cardiac chest pain due to ischemia.
- Usually caused by atherosclerosis i.e. ischaemic heart disease (IHD). Less commonly due to valve disease (esp. aortic stenosis), arrhythmias, hypertrophic cardiomyopathy, anaemia, or coronary vasospasm (e.g. cocaine-induced).
- Affects 1/10 over 65 years old. Commoner in men.
Signs and symptoms
Intermittent, stable chest pain with 3 classic features, ECG:
- Exertion as precipitant.
- Constricting discomfort of the anterior chest, which may radiate to neck, shoulders, jaw, or arms.
- GTN or rest provides relief within 5 minutes.
3/3 = typical angina, 2/3 = atypical angina, 1/3 = not angina.
Investigations
Basic tests:
- Bloods: FBC (rule out ↓ Hb), U&E (co-morbid CKD, ACEi baseline), and CVD risk factor investigations, including BP, lipids, and glucose.
- ECG: often normal, but may show ischaemic changes (Q waves or ST-T changes).
Diagnostic testing for IHD should be offered to all those with typical/atypical angina or an ischaemic ECG:
- CT coronary angiogram (CTCA) is 1st line.
- Functional imaging using stress agent if CTCA non-diagnostic: stress echo (+ exercise or dobutamine stress), myocardial perfusion scintigraphy (+ adenosine, dipyridamole, or dobutamine stress), or MR perfusion (+ adenosine or dipyridamole stress).
- Invasive angiography if functional imaging non-diagnostic.
For those with known IHD (e.g. previous MI or angiography, hence no CTCA indicated) with chest pain of uncertain cause, consider:
- Functional imaging (as above).
- Exercise ECG. Note this is not recommended by NICE for the initial diagnosis of IHD.
Management
3 components.
1. Anti-anginals:
- 1st line: β-blockers and/or calcium channel blockers. Use both if one is insufficient.
- 2nd line: isosorbide mononitrate (ISMN), nicorandil (K+ channel opener), ivabradine (l ‘ f ‘ channel blocker), or ranolazine (‘late’ Na+
channel blocker). Can be used as monotherapy or in combination with 1st line drug(s). - Consider revascularisation if not controlled by two drugs. PCI for one or two vessels; CABG for left main or triple vessel disease. Both relieve symptoms but only CABG reduces mortality.
2. Short-acting nitrate:
- GTN spray or sublingual tablets.
- Use before planned activity and when symptomatic.
- If pain continues for 5 minutes after 1st dose, call an ambulance and take 2nd dose.
- Side effects: headache, flushing, and light-headedness.
3. CVD prevention:
- Aspirin for all (clopidogrel 2nd line), and consider statins and ACEI.
- Lifestyle changes, through simple advice or as part of cardiac rehab. Includes exercise, healthy weight, stop smoking, and the Mediterranean diet. Exercise should be for 30 minutes per day but below the anginal threshold.