Acute coronary syndrome Flashcards
What does acute coronary syndrome cover?
- ST elevation myocardial infarction (STEMI)
- non-ST elevation myocardial infarction (NSTEMI)
- unstable angina
How is chest pain in ACS usually described?
Chest pain:
- typically central/left-sided
- may radiate to the jaw or the left arm
- ‘heavy’ or constricting, ‘like an elephant on my chest’
- in real clinical practice patients present with variety of types of chest pain :. confuse ischaemic pain for other causes e.g. dyspepsia
- diabetics/elderly may not experience any chest pain
What are other symptoms of ACS?
- dyspnoea
- sweating
- nausea and vomiting
What are signs of ACS?
- pulse, blood pressure, temperature and oxygen saturations are often normal or only mildly altered e.g. tachycardia
- if complications of the ACS have developed e.g. cardiac failure then clearly there may a number of findings
- the patient may appear pale and clammy
What are the two most important investiogations in ACS?
- ECG
- cardiac markers e.g. troponin
Which leads correlate to the arteries of the heart plus view?
Anterior: V1-V4 = Left anterior descending
Inferior: II, III, avF = Right coronary
Lateral: I, V5-6 = Left circumflex
How do you manage ACS?
- prevent worsening of presentation (i.e. further occlusion of coronary vessel)
- revascularise (i.e. ‘unblock’) the vessel if occluded (patients presenting with a STEMI)
- treat pain
Morphine
Oxygen (if sats <94%)
Nitrates
Aspirin
How do you manage a STEMI?
How do you manage NSTEMI?
What is the secondary prevention of ACS?
- aspirin
- a second antiplatelet if appropriate (e.g. clopidogrel)
- a beta-blocker
- an ACE inhibitor
- a statin
When would you not give fondaparinux in NSTEMI?
- If angiography likely within 24 hours
- Patients creatinine is > 265 µmol/l
Unfractionated heparin should be given instead
When is prasugrel preferred? How long do you continue antiplatelet therapy?
- If the patient is going to have a percutaneous coronary intervention
- Generally given to all patients and continued for 12 months
- vary according to bleeding/ischaemic risk.
When are Intravenous glycoprotein IIb/IIIa receptor antagonists(eptifibatide or tirofiban) given in NSTEMI?
- scheduled to undergo angiography within 96 hours of hospital admission
- intermediate or high risk of adverse cardiovascular events
What is the mechanism of aspirin?
Antiplatelet - inhibits the production of thromboxane A2
What is the mechanism of clopidogrel?
Antiplatelet - inhibits ADP binding to its platelet receptor
What is the mechanism of enoxaparin and fondaparinux?
Activates antithrombin III, which in turn potentiates the inhibition of coagulation factors Xa
What is the mechanism of bivalirudin?
Reversible direct thrombin inhibitor
What is the mechanism of abciximab, eptifibatide and tirofiban?
Glycoprotein IIb/IIIa receptor antagonists
What is intermediate/high risk of adverse cardiovascular events in the GRACE score?
predicted 6-month mortality above 3.0%
What treatments are given in STEMI prior to PCI?
Following initial steps there is a large amount of variation in practice in terms of which other medications are given prior to PCI.
Other treatments that may be given include bivalirudin (a direct thrombin inhibitor, usually given alongside aspirin + clopidogrel) and a form of heparin (either low-molecular weight or unfractionated).
What are the prognostic factors for ACS?
Poor prognostic factors:
- age
- development (or history) of heart failure
- peripheral vascular disease
- reduced systolic blood pressure
- Killip class*
- initial serum creatinine concentration
- elevated initial cardiac markers
- cardiac arrest on admission
- ST segment deviation
What is Killip class?
System used to stratify risk post myocardial infarction
