Unstable angina Flashcards
What is unstable angina?
ACS that is defined by the absence of biochemical evidence of myocardial change. When blood supply to heart is seriously restricted, but there is no permanent damage, so heart muscle is preserved.
What are the 2 most common presenting symptoms?
Chest pain +/- dyspnoea.
How is UA defined and characterised?
Defined by absence of biochemical evidence of myocardial damage.
Characterised by:
· Prolonged, >20 minutes, angina at rest.
· New onset severe angina.
· Angina that’s increasing in frequency.
· Angina that’s longer in duration or lower in threshold.
· Angina that occurs after a recent episode of myocardial infarction.
How common is UA?
Heart disease remains the leading cause of death among white men and women.
But CVD mortality is decreasing.
What is the pathophysiology of UA?
· A fissure develops in the vessel endothelial lining, over an underlying cholesterol plaque.
· This causes a loss integrity of the plaque cap.
· Plaque rupture leads to exposure of sub-endothelial matrix, stimulating platelet activation and thrombus formation.
· Release of tissue factor activates the coagulation cascade, promoting the formation of fibrin.
· If the thrombus formation is not occlusive, the patient develops UA or non-specific ST changes on the ECG.
What are the 4 prognostic markers?
- Rest pain.
- Presence of comorbidity.
- Signs of LVF.
- ST depression on ECG.
What is the aetiology of UA?
· Coronary artery disease - underlying cause in nearly all pts:
- Most commonly due to coronary artery narrowing caused by a thrombus that develops on a disrupted atherosclerotic plaque.
- Usually non-occlusive.
- Less common cause is vasospasm of a coronary artery - intense vasospasm is caused by vascular smooth muscle or by endothelial dysfunction.
List the possible risk factors.
· Females. · History of CAD. · Men >45 years. Women >55 years. · FH of CAD. · HTN. · Smoking. · Diabetes. · Hyperlipidaemia. · PVD. · CKD.
What are the signs and symptoms of UA?
· Chest pain:
- ST/T abnormalities - Troponin normal - Unstable angina.
- Normal ECG - Troponin normal - Unstable angina.
· Retrosternal pain radiating to jaw, arm or neck. · Dyspnoea. · Fourth heart sound (S4). · Diaphoresis. · Nausea. · Tachycardia. · Carotid bruit.
What investigations would you request if you suspected a patient had UA?
· ECG. May be normal or have transient ST depression or T wave inversion.
· Cardiac biomarkers. Not elevated.
· FBC, U&Es, blood sugar, lipid profile, coagulation profile.
· CXR. HF will show pulmonary oedema.
· Coronary angiography - fold standard for assessing presence of CAD.
· Lipid profile - increased.
List some differential diagnoses.
· Stable angina. · Prinzmetal (variant) angina. · NSTEMI - ECG may be normal or show ST depression or T wave inversion. Cardiac biomarkers will be raised. · STEMI - persistent ST elevation in 2 or more leads. Cardiac biomarkers are raised. · Congestive heart failure. · Chest wall pain. · Pericarditis. · Myocarditis. · Aortic dissection. · PE. · Pleuritis. · Pneumothorax. · Perforated abdominal viscus.
What symptoms would suggest stable angina instead of unstable angina?
Pain would only occur on exertion or stress, not worsening over time, and would be relieved by nitrates.
What is the treatment option for presumed cardiac chest pain?
· 1st - Oxygen, nitrates (GTN) and morphine.
· Plus - Beta-blocker.
· Plus - Anti-platelet therapy.
What is the treatment option of confirmed UA?
· 1st - Anti-platelet therapy. · Plus - Statin. · Aspirin (without stenting) or clopidogrel (with stenting) · Adjunct - Beta-blocker. · Adjunct - ACEi. · Plus - Cardiac rehabilitation.
What complications can occur?
· Treatment complication - Bleeding.
· Treatment complication - Thrombocytopenia.
· Congestive heart failure.
· Ventricular arrhythmias.
