Acute coronary syndromes Flashcards
1
Q
What are acute coronary syndromes?
A
- They include unstable angina, STEMI and NSTEMI
- They occur following a ruptureed plaque, thrombosis and occlusion and inflammtion
2
Q
What is the pathophysiology of ACS?
A
- Repetitive injury to the endothelium from physical stress, infection, oxidative stress, high cholesterol, toxins in cigarette smoke etc.
- Injury increases permeability of intima to plasma proteins, these oxidise LDLs in the blood, allowing their uptake through the intima.
- Monocytes/macrophages penetrate the endothelium and oxidise lipids becoming foam cells
- Platelet adherence increases which allows smooth muscle cells proliferation and migration into the area à forms a fibrous cap (increased collagen synthesis aids cap formation)
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3
Q
What does myocardial infarction and ischaemia mean?
A
- Myocardial cell death that is leading to release of troponin
- Ischaemia means lack of blood supply +/- cell death
4
Q
What are the risk factors of ACS?
A
- Modifiable:
- Smoking
- Excessive alcohol intake
- Diabetes control
- Hypertension control
- Hyperlipidaemia
- Obesity
- Sedentary lifestyle
- Cocaine use
- Non-modifiable:
- Age >60
- Gender (males are more susceptible)
- Family history
5
Q
What are some controversial risk factors for ACS?
A
- Stress
- Type A personality
- LVH
- Fibrinogen increase
- Hyperinsulinaemia
- Increase in homocysteine levels
6
Q
How is ACS diagnosed?
A
- Troponin increase (cardiac biomarker)
- ECG changes of new ischaemia (development of pathological q waves)
- Symptoms of ischaemia
- Loss of myocardium
7
Q
What are the symptoms of ACS?
A
- Crushing central chest pain that radiates to the neck, jaw, shoulder and arm, lasting >20 mins
- Sweating
- Nausea
- Sweatiness
- Dyspnoea
- ACS without chest pain = silent (seen in elderly and diabetes)
8
Q
What is a silent MI? How does it present?
A
- ACS without chest pain = silent (seen in elderly and diabetes)
- Syncope
- Pulmonary oedema
- Epigastric pain
- Vomiting
- Post-operative hypotenison
- Oligouria
- Acute confusional state
- Stroke
- Diabetic hyperglycaemic state
9
Q
What are the signs of ACS?
A
- Pallor
- Distress
- Anxiety
- Sweatiness
- Changes in pulse, BP
- 4th heart sound
- SIgns of heart failure
- Pansystolic murmour
- Low grade fever
- Pericardial friction rub or peripheral oedema may develop
10
Q
What is seen in ECG for STEMI in order?
A
- Hyperacute T waves
- ST elevation
- Or LBBB within hours
- R waves decrease
- T wave inversion (hours or days)
- Q waves form (pathological, hours or days)
- T waves return to normal
- Pathological Q waves remain
11
Q
What signs in ECG are seen for NSTEMI and unstable angina?
A
- ST depression
- T wave inversion
12
Q
How can you differentiate between unstable angina and NSTEMI?
A
- Troponin T and I in NSTEMI not unstable angina
13
Q
What other investigations can be carried out to diagnose ACS and what can be seen?
A
- CXR
- Look for cardiomegaly
- Pulmonary oedema
- Widened mediastinum
- Blood
- FBC
- U&Es
- Glucose
- Lipids
- Cardiac enzymes - troponin T and I are the most sensitive and specific markers of myocardial necrosis
- ECHO
- Regional wall abnormalities
14
Q
What are differential diagnosis of ACS?
A
- Stable angina
- Pericarditis
- Myocarditis
- Takotsubo cardiomyopathy
- Aortic dissection
- PE
- Oesophageal reflux/spasm
- Pneumothorax
- MSK pain
- Pancreatitis
15
Q
What would make the prognosis worse in ACS?
A
- Elderly
- LV failure
- ST changes
16
Q
Which other disease can troponin be high in?
A
- Other causes of myocardial damage:
- Myocarditis
- Pericarditis
- Ventricular strains
- Iatrogenic
- Discrete episodes of tachyarrythmias
- A common cause of consistently raised troponin is in renal failure
- Hence change in level is more important than the level itself
17
Q
How is ACS with ST elevation managed?
A
- Aspirin/ Ticagrelor
- Morphine with anti-emetic (metaclropromide - 1st line or cyclizine - 2nd line)
- GTN - routine use is now not recommended in the acute setting unless the patient has hypertension or acute LVF
- useful as anti-anginal in chronic or stable patients
- Oxygen
- Restore coronary perfusion - in those presenting <12 hours after symptoms
- Anticoagulation - bivalirudin is preferred, enoxiparin is 2nd line
- Beta blocker - useful as add on when started early
- Bisoprolol
18
Q
What is the reperfusion therapy used for ACS?
A
- Primary PCI
- Should be offered to all patients presenting within 12hrs of symptoms with a STEMI and if they can get it done within 120 mins of medical contact
- If not possible, thrombolysis should be given and patient should be transferred to a primary PCI centre for PCI rescue or angiography
- Can be used beyond 12 hrs if there is evidence of ongoing ischaemia or in stable patients presenting after 12-24hrs (seek specialist advice)
- Thrombolysis
- The benefit of this reduces tfrom the onset of pain (ie. the longer its taken to be given)
- Do not thrombolye ST depression alone, T wave inversion alone or no ECG change
- Best achieved with tissue plasminogen activators
19
Q
What should happen to a patient with STEMIs that do not receive reperfusion?
A
- They should be treated with fondaparinux
- Enoxaparin
- Unfractionated heparin if not available
20
Q
What are the contraindications of thrombolysis?
A
- Previous intracranial haemorrhage
- Ischaemic stroke
- Cerebral malignancy or AVM
- Recent major trauma/surgery/head injury
- GI bleeding
- Known bleeding disorders
- Anticoagulant therapy
- Pregnancy
21
Q
How is ACS without ST elevation managed?
A
- Aspirin and clopidogrel - oral anti-platelet therapy
- The clopidogrel should be given to a select group of patients
- Low molecular weight heparin
- (enoxiparin)
- Glycoprotein IIa/IIb inhibitors
- For those with recurrent chest pain and ECG changes despite standard treatment
- Nitrates
- For recurrent chest pains
- Beta blockers
- Unless contraindicated then non-dihydropyrimidine calcium channel blockers should be used
- ACEi - all patients unless contraindicated
- Lipid management
- Statin
22
Q
Which groups of patients should aspirin and clopidogrel or just clopidogrel be given to in those with ACS without ST elevation?
A
- Raised tropinin
- ACS already on aspirin
- ST depression at rest ECG
- ACS after recent MI
- Patients being transferred for angioplasty
- Aspiring intolerant
23
Q
When should clopidogrel not be used?
A
- Routinely for patients with suspected cardiac pain in the absence of ECG changes or raised troponin
24
Q
What is the subsequent management for ACS?
A
- Bed rest for 48hrs
- Daily examination of heart, lungs and legs for complications
- Prophylaxis against thromboembolism until they are fully mobile
- Aspiring
- Long term beta blockers
- Again, if CI, use diltiazem or verapimil
- Continue ACEi
- Start or continue statins
- Address modifiable risk factors
- Smoking
- Encourage exercise - daily
- Optimise hypertension, diabetes, hyperlipidaemia
- Exercise ECG
- General advice:
- Work - return after 2 months
- some jobs may not be appropriate to restart (heavy lifting, airline pilot, divers, air traffic controllers)
- Sex - avoid for 1 month
- Travel - avoid for 2 months
- Diet - oily fish, fruit, vegetables, fibre
- Driving - group 1 can return to driving after 1 - 4 weeks depending on if they have had an angioplasty or not. group 2 must inform the DVLA and stop driving until they get good functional tests
- Work - return after 2 months
25
Q
Why can you not prescribe beta blockers with diltiazem or verapimil?
A
- Diltiazem should be used with caution if given with beta blockers due to risk of bradycardia.
- Verapamil is used for angina, hypertension and arrhythmia; it reduces cardiac output, slows the heart rate and may affect atrioventricular conduction. It should not be used with beta–blockers.
- When combined, they cause a further lowering in heart rate and blood pressure while prolonging atrioventricular node conduction.
- So because of the risk of bradycardia it should be used with caution in association with beta-blockers.
26
Q
What are the complications of MI? (13)
A
- Cardiac arrest
- Cardiogenic shock
- Bradycardias or heart block
- Tachyarrhythmias
- Heart failure
- Pericarditis
- DVT/PE
- Systemic embolism
- Cardiac tamponade
- Mitral regurgitation
- VSD
- Dresslers syndrome
- Left ventricular aneurysm
27
Q
When is revascularisation indicated in ACS?
A
- STEMI patients
- Very high risk STEMI patients
28
Q
Which revascularisation techniques should be used with patients?
A
- Immediate angiography and PCI wihtin 24hrs
- Intermediate risk patients should have angiography and PCI within 3 days
- Low risk patients should be considered for non-invasive testing
- Patients with multivessel disease may be considered for CABG instead of PCI
29
Q
What are the indications for CABG?
A
- Indications to improve survival
- Left main stem disease
- Triple vessel disease involving proximal part of the left anterior descending
- Abnormal LV function
- Indications to relieve symptoms
- Angina unresponsive to drugs
- Unstable angina
- If angioplasty fails
30
Q
What are the advantages and disadvantages of CABG over PCI?
A
Advantages
- More complete long term relief of angina
- Less repeated revasculisation
Disadvantages
- Longer recovery time
- Longer inpatient stay
31
Q
Describe the CABG procedure
A
- The heart is usually stopped and blood is pumped around artificially by a machine outside the body
- Saphenous vein or internal mammary artery is used as the graft
- Internal mammary artery grafts last longer but may casue chest wall numbness
- >50% of vein grafts close in 10 years but low dose aspiring helps to prevent this
- Several grafts may be placed
