Angina (Unstable) Flashcards
What is angina?
Angina is pain (or constricting discomfort) in the chest, in the neck, shoulders, jaw, or arms caused by an insufficient blood supply to the myocardium.
What is unstable angina?
New onset angina or abrupt deterioration in previously stable angina, often occurring at rest. Unstable angina usually requires immediate admission or referral to hospital.
Briefly describe the cause of angina
Angina is usually caused by coronary artery disease- atherosclerotic plaques in the coronary arteries cause progressive narrowing of the lumen, and symptoms occur when blood flow does not provide adequate amounts of oxygen to the myocardium at times when oxygen demand increases (such as during exercise).
Less commonly, angina is caused by valve disease (for example aortic stenosis), hypertrophic obstructive cardiomyopathy, or hypertensive heart disease.
What are the risk factors associated with unstable angina?
- Diabetes
- Hyperlipidaemia
- Hypertension
- Metabolic syndrome
- Renal impairment
- Peripheral arterial disease
- A history of ischaemic heart disease and any previous treatment
- Obesity
- Advanced age
- Smoking
- Cocaine use
- Physical inactivity
What are the signs of unstable angina?
Physical examination may be normal in patients with unstable angina.
What are the symptoms of unstable angina?
- Chest pain
- Consider ACS in any patient presenting with acute chest pain, which includes other areas (e.g., the arms, back, or jaw), especially if this is associated with nausea and vomiting, marked sweating, and/or breathlessness, or particularly a combination of these.
What investigations should be ordered for unstable angina?
- ECG
- Troponin
- CXR
- FBC
- Urea, electrolytes and creatinine
- LFTs
- Blood glucose
- CRP
- Echocardiogram
Why investigate using ECG?
Record and interpret a resting 12-lead ECG within 10 minutes of the point of first medical contact.
Typically no ECG changes; ST depression (indicates a worse prognosis), transient ST elevation, and T-wave changes may be seen.
Why investigate troponin?
Diagnosis of ACS typically requires serial troponins (e.g. at baseline and 6 or 12 hours after onset of symptoms). A rise in troponin is consistent with myocardial ischaemia as the proteins are released from the ischaemic muscle. They are non-specific, meaning that a raised troponin does not automatically mean ACS.
In unstable angina there is no dynamic elevation.
Which troponins are the most specific to the heart?
Troponin I and T.
What are the other causes of a rise in troponin?
- Chronic renal failure
- Sepsis
- Myocarditis
- Aortic dissection
- Pulmonary embolism
Why investigate using CXR?
The UK National Institute for Health and Care Excellence recommends ordering a chest x-ray only if you suspect other diagnoses or to rule out complications of acute coronary syndrome.
Other causes of acute chest pain such as pneumothorax or a widened mediastinum in aortic dissection and complications of acute coronary syndrome such as pulmonary oedema due to heart failure.
Why investigate FBC?
Check full blood count to evaluate thrombocytopenia to estimate risk of bleeding; unstable angina treatment increases the risk of bleeding.
Investigate any possible secondary causes of unstable angina (i.e., secondary blood loss, anaemia).
Why investigate U&Es and creatinine?
Measure renal function to determine serum creatinine and estimated glomerular filtration rate; these are key elements in assessing the Global Registry of Acute Coronary Events (GRACE) risk score.
Helps determine the choice/dose of anticoagulant
Prevent contrast-induced nephropathy if an invasive strategy is planned in a patient with renal impairment.
Why investigate LFTs?
Measure liver function to include in the assessment of bleeding risk before starting anticoagulation and statins.
Why investigate blood glucose?
Check blood glucose in any patient with known diabetes or hyperglycaemia on admission to hospital regardless of a history of diabetes.
Why investigate using CRP?
CRP is commonly ordered to rule out other causes of acute chest pain (e.g., pneumonia).
Can be elevated in infection.
Why investigate using echocardiogram?
Echocardiogram after the event to assess the functional damage and any regional wall abnormalities.
Briefly describe the acute treatment for unstable angina
Initial antiplatelet therapy: offer loading dose of aspirin and continue aspirin indefinitely unless contraindicated Initial antithrombin therapy
Initial antithrombin therapy: offer fondaparinux unless high bleeding risk or immediate angiography.
Consider:
- Glyceryl trinitrate
- Morphine
- Anti-emetic
- P2Y12 inhibitor
- Anti-coagulation
What is the benefit of giving aspirin in unstable angina?
Give all patients with suspected unstable angina a single loading dose of aspirin as soon as possible, unless they have significant bleeding risk or hypersensitivity to aspirin.
Aspirin is given for its antiplatelet effect.
Following aspirin therapy, what is used as a secondary antiplatelet agent?
If no separate indication for oral anticoagulation, offer ticagrelor with aspirin.
If a person has a separate indication for oral anticoagulation, offer clopidogrel with aspirin.
Only give prasugrel once PCI intended.
Briefly describe the secondary prevention of unstable angina
Note: medical management
- Aspirin 75mg once daily
- Another antiplatelet: e.g. clopidogrel or ticagrelor for up to 12 months
- Atorvastatin 80mg once daily
- ACE inhibitors (e.g. ramipril titrated as tolerated to 10mg once daily)
- Atenolol (or other beta blocker titrated as high as tolerated)
- Aldosterone antagonist for those with clinical heart failure (i.e. eplerenone titrated to 50mg once daily)
Briefly describe the secondary prevention of unstable angina
Note: lifestyle advice
- Stop smoking
- Reduce alcohol consumption
- Mediterranean diet
- Cardiac rehabilitation (a specific exercise regime for patients post MI)
- Optimise treatment of other medical conditions (e.g. diabetes and hypertension)
What scoring system is used to assess if PCI is indicated in unstable angina and NSTEMI?
GRACE score.
Briefly describe GRACE score
Used to assess if PCI is needed in unstable angina and NSTEMI
This scoring system gives a 6-month risk of death or repeat MI after having an NSTEMI:
- <5% Low Risk
- 5-10% Medium Risk
- >10% High Risk
If they are medium or high risk they are considered for early PCI (within 4 days of admission) to treat underlying coronary artery disease.
What is percutaneous coronary intervention (PCI)?
Percutaneous Coronary Intervention (PCI) involves putting a catheter into the patient’s brachial or femoral artery, feeding that up to the coronary arteries under xray guidance and injecting contrast to identify the area of blockage. This can then be treated using balloons to widen the gap or devices to remove or aspirate the blockage. Usually a stent is put in to keep the artery open.
What complications are associated with unstabe angina?
- Complication of treatment: bleeding
- Complication of treatment: thrombocytopenia
- Congestive heart failure
- Ventricular arrthymias
What differentials should be considered in unstabe angina?
- Stable angina
- Prinzmetal (variant or vasospastic angina
- NSTEMI
- STEMI
How does unstable angina and stable angina differ?
Differentiating signs and symptoms:
- Pain occurs only in context of exertion or emotional stress, not worsening over time, and relieved by nitrates or rest
Differentiating investigations:
- ECG may be normal in the absence of pain but may show ST depression during episodes of angina or on stress testing
How does unstable angina and prizmetal (variant or vasospastic) angina differ?
Differentiating signs and symptoms:
- Typically occurs without provocation and usually resolves spontaneously or with rapid-acting nitrate
- May be precipitated by emotional stress, hyperventilation, exercise, or a cold environment
Differentiating investigations:
- ST elevation during acute episode
- Coronary angiography (invasive or non-invasive) excludes severe obstructive coronary artery disease but may show spasm
How does unstable angina and NSTEMI differ?
Differentiaing signs and symptoms:
- Clinical presentation may be indistinguishable
Differentiating investigations:
- ECG may be normal or show ST depression or T wave inversion. Cardiac biomarkers (troponin, creatine kinase [CK], CK-MB) are raised
How does unstable angina and STEMI differ?
Differentiating signs and symptoms:
- Clinical presentation may be indistinguishable
Differentiating investigations:
- ECG shows persistent ST elevation in 2 or more leads. Cardiac biomarkers (troponin, creatine kinase [CK], CK-MB) are raised
