Cardiology - Acute Coronary Syndromes Flashcards
What causes an acute coronary syndrome?
Thrombus from an atherosclerotic plaque blocking a coronary artery
Why are anti-platelet medications used in acute coronary syndromes?
Thrombus formation occurs in a fast-flowing artery
Formed mainly from platelets
What are 3 main anti-platelet medications?
Aspirin
Clopidogrel
Ticagrelor
What is the mechanism of action of aspirin?
Inhibits cyclooxygenase-1 from producing thromboxane A2 from arachidonic acid
Reduces platelet aggregation
Irreversible
Why do anti-platelet medications last the lifespan of the platelet?
Platelets have no nuclei
Cannot produce more COX-1
What is the mechanism of action of clopidogrel and ticagrelor?
Clopidogrel
Irreversible
Ticagrelor
Reversible
Both prevent binding of ADP to P2Y12 receptors
This inhibits activation of Glycoprotein IIb/IIIa receptors
Less aggregation
What are the three types of acute coronary syndrome?
Unstable angina
ST-elevation myocardial infarction (STEMI)
Non-ST-elevation myocardial infarction (NSTEMI)
What does the right coronary artery supply?
RA
RV
Inferior LV
Posterior 1/3 inter ventricular septum
Posterior heart
What does the left coronary artery become?
Circumflex artery
Left anterior descending artery
What does the circumflex artery supply?
Left atrium
Posterior aspect of the left ventricle
Lateral heart
What does the left anterior descending supply?
Anterior left ventricle
Anterior 2/3 of the interventricular septum
How does acute coronary syndrome present?
Central, constricting chest pain
- Pain radiates to the jaw or arms
- Nausea and vomiting
- Sweating and clamminess
- Feeling of impending doom
- Shortness of breath
- Palpitations
Symptoms continue at rest for more than 15 minutes
What is a silent myocardial infarction and who experiences it?
Do not experience typical chest pain during acute coronary syndrome
Diabetics at much higher risk
Complete the table
What type of acute coronary syndrome is troponin needed for diagnosis?
NSTEMI
Not needed for STEMI as based on presentation and ECG
Asides from acute coronary syndromes what else can cause raised troponin?
CKD
Sepsis
Myocarditis
Aortic dissection
PE
What additional investigations should be done for suspected or confirmed acute coronary syndromes?
Baseline bloods
CXR
- Pulmonary oedema
Echocardiogram
- Assess functional damage to heart, specifically LV function
What is different in investigations between unstable angina and NSTEMI?
Raised troponin in NSTEMI
Both have either:
- Normal ECG
- ST depression or T wave inversion
If a patient is pain-free but had pain within 72 hours what should be done?
Referred to hospital for same-day assessment
May have ECG changes
How are patient’s with a STEMI managed?
Percutaneous coronary intervention (PCI)
WITHIN 12 hours of symptom onset
Within 2 hours of presenting to the hospital
Thrombolysis
If PCI not available within 2 hours
What fibrinolytics are used in thrombolysis?
Streptokinase (can only be used once as antibodies develop against it)
Alteplase
Tenecteplase
How do fibrinolytics work?
Converts plasminogen to plasmin which enables degradation of fibrin
How should NSTEMI and STEMI be managed?
STEMI
MONA
Morphine
Oxygen
Nitrate (GTN)
Aspirin 300mg
PCI and thrombolysis
NSTEMI
BATMAN
Based on GRACEscore for PCI
Aspirin 300mg
Ticagrelor
Morphine
Anti-thrombin (fondaparinux)
Nitrates
What is the GRACE score?
6 month probability of death after NSTEMI
3% or less- Low risk
Over 3%- Medium to high risk
Medium to high risk patients considered for angiography with PCI within 72 hours
