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.
