Stable Angina

By YardCard Team

Stable angina is a syndrome of chest pain/pressure that accompanies myocardial ischaemia, typically triggered by physical activity or stress.

It falls within the category of chronic coronary syndromes.

NICE defines typical angina as chest pain with all 3 of the following features:

• precipitated by physical exertion
• constricting discomfort in the front of the chest, in the neck, shoulders, jaw or arms
• relieved by rest or GTN within about 5 minutes

Atypical angina presents with two of the above features.

Presence of certain risk factors make the diagnosis more likely. These are:

• Non-modifiable RFs: Older age, male sex, family history of cardiovascular disease, ethnic background (e.g. South Asian)
• Modifiable RFs: smoking, LDL to HDL ratio >5, diet, alcohol excess, overweight, obesity

Unstable angina is a type of acute coronary syndrome (ACS) that is characterised by agninal symptoms at rest and requires immediate management.

Clinical assessment

• Looking for signs and symptoms
• Differentiating non-cardiac causes of chest pain
• Ruling out ACS

Signs and symptoms

Characteristic	Decreasing likelihood of chronic coronary syndrome (IHD)	Increasing likelihood of chronic coronary syndrome (IHD)
Quality	Burning, Sharp, Tearing, Ripping, Pleuritic, Aching,	Strangling, Constricting, Squeezing, Pressure, Heaviness
Location and size	Right, Shifting, Large area or fine spot	Retrosternal, Extending to left arm, or to jugular or intrascapular region, Diffuse area
Duration	Lasting	Short: up to 5-10 min if triggered by physical exertion or emotion
Trigger	At rest, On deep inspiration or when coughing, When pressing on ribs or sternum	On effort, More frequent in cold weather, strong winds or after a heavy meal, Emotional distress
Relief	By antacids, drinking milk	Subsiding within 1-5 min after effort discontinuatio. Relief accelerated by GTN
Dyspnoea Quality	Difficulty to exhale, With wheezing	Difficulty catching breath
Dyspnoea Trigger	Both at rest and on effort, While coughing	On effort
Dyspnoea Relief	Slowly subsiding at rest or after inhalation of salbumatol	Rapidly subsiding after effort discontinuation

 

Note that this isn’t as straightforward as the NICE criteria for 'typical' angina - in some patients pain can be completely absent (especially in autonomic dysfunction) and more and more patients are getting asymptomatic coronary artery disease picked up incidentally on CT.

Patients can present more atypically with micovascular disease or vasospasm - so not meeting the classic definitions of typical and atypical angina doesn’t necessarily mean the pain must be non-cardiac.

Pathophysiology

CCS now incorporates non-obstructive conditions like ANOCA (angina with non-obstructive coronary arteries) and INOCA (ischemia with non-obstructive coronary arteries). Dysfunction in smaller coronary arteries or due to systemic factors like high BP or anaemia can contribute to these syndromes.

Examination

• Cardiovascular examination
• Blood pressure
• BMI

Investigations

ECG - all patients

12-lead ECG can be used to look for evidence of old myocardial infarction (e.g. pathological Q waves) and conduction abnormalities (especially LBBB and AV block) and to look for ACS

ECG changes that can indicate myocardial ischaemia include:

• Pathological Q waves - a marker of electrical silence (25% or more of the height of the R wave and/or >1 small square wide and >2 small squares deep) - note may be normal in lead III
• LBBB
• ST segment and T wave abnormalities (flattening, elevation, inversion)

Blood tests

• Lipids - assess risk, guide treatment
• Troponin - acute myocardial damage
• TSH - hyperthyroidism can cause ischaemia
• FBC - severe anaemia can cause ischaemia
• U&E, eGFR: renal dysfunction increases likelihood of IHD and affects drug excretion, required before starting any ACEi
• Hba1c

Further tests

• Echocardiography - rule out LV dysfunction and valvular heart disease
• CXR: if considering heart failure, acute pulmonary disease, or suspected thoracic cause of chest pain
• Further tests can be based on the likelihood of CAD - can include angiography
• CT angiography is gaining favour as the first-line diagnostic approach due to its non-invasiveness and accuracy in detecting atherosclerosis. Functional testing, such as stress imaging, is recommended for patients with higher likelihoods of obstructive CAD or when CT imaging is not suitable.

Principles of management

• Refer to cardiologist (usually RACP)
• Medical treatment of angina
• Secondary prevention: cardioprotective diet and weight management advice, smoking cessation, medications
• Interventions - can include surgery and angioplasty

Referral to cardiologist

• If angina is suspected (usually if chest pain meets the criteria for atypical or typical anginal chest pain) you would refer to a Rapid Access Chest Pain (RACP) clinic to confirm the diagnosis and assess CAD severity.
• While waiting for specialist input, give sublingual GTN and tell them that if they experience chest pain, to stop and use the spray but if the pain hasn’t eased after 5 minutes to call 999.
• If there is rest pain, pain on minimal exertion, or angina that is rapidly progressing consider admission due to unstable angina/ACS

Guideline-based medical treatment

First-line treatment is a β blocker or calcium channel blocker (CCB) to reduce symptoms.

Beta blockers used in angina are cardio-selective e.g. bisoprolol

If a β blocker isn’t tolerated, try a CCB and vise versa

CCBs used alone are usually rate-limiting such as diltiazem particularly if the patient isn’t bradycardic.

If using a CCB in combination with a β blocker, use a dihydropyridine CCB (e.g. amlodipine) as rate-limiting CCBs are cautioned with β blockers.

The next step if CCB + bisoprolol is not controlling symptoms is adding a long acting nitrate (Isosorbide Mononitrate) and referring to a specialist.

The next step would then be adding nicroandil - but not in patients with GI ulceration. You could alternatively add ivabradine under the direction of cardiology - this drug can cause bradycardia so must be used with caution.

The next step would then be ranolazine which can only be initiated by the cardiologist and the patient isn’t suitable for revascularisation.

Medications for secondary prevention

• Asprin 75mg OD (taking into account bleeding risk and co-morbidities)
• ACE inhibitors (if stable angina + diabetes)
• Statin treatment
• Optimise hypertension and diabetes management

Invasive treatment

There are 2 options for invasive treatment of coronary artery disease:

• Percutaneous coronary intervention (PCI)
• Coronary artery bypass graft (CABG)

Referral for possible revascularisation should be considered in patients with a very high likelihood of obstructive coronary artery disease, when disease is more severe and where medical treatments do not control symptoms.

Revascularisation is often possible with PCI, but some may require CABG.

CABG is preferred for left main vessel disease, multivessel disease with diabetes or complex anatomy, and LV dysfunction and reduces mortality.

PCI is preferred for single and 2-vessel disease especially in patients unfit for surgery or low complexity left main vessel disease

ISCHEMIA Trial: The ISCHEMIA trial showed that in patients with moderate-severe angina but no left main disease or LVEF <35%, initial invasive strategies did not significantly improve primary endpoints (ischaemic cardiovascular events + death) but did reduce spontaneous myocardial infarction (MI) and symptoms. This indicates that an invasive initial strategy is not better than medical management for reduction of mortality and cardiovascular events. 

References

1. Christiaan Vrints, Felicita Andreotti, Konstantinos C Koskinas et al., ESC Scientific Document Group , 2024 ESC Guidelines for the management of chronic coronary syndromes: Developed by the task force for the management of chronic coronary syndromes of the European Society of Cardiology (ESC) Volume 45, Issue 36, 21 September 2024, Pages 3415–3537, https://doi.org/10.1093/eurheartj/ehae177
2. National Institute for Health and Care Excellence (2022). Angina. [online] NICE. Available at: https://cks.nice.org.uk/topics/angina/.

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