Acute coronary syndrome

• What is angina?

  Chest pain due to insufficient O2 reaching the myocardium during exertion
• What is acute coronary syndrome (ACS)?

  A group of conditions resulting from decreased blood flow to the heart

  Unstable angina

  NSTEMI

  STEMI
• What is the classification of angina based on severity, frequency & duration of symptoms?

  New onset severe angina

  • angina that has developed within the last month
  • pts require immediate evaluation & treatment (due to high risk of MI)

  Increased/crescendo angina

  • progressive increase in severity, frequency or duration of anginal episodes over time
  • often indicates worsening coronary artery disease & impending ACS

  Rest/nocturnal angina

  • anginal pain at rest or during sleep
  • suggests significant coronary artery obstruction -> may be a sign of critical myocardial ischaemia
• What is the classification of angina based on clinical circumstances?

  Braunwald Classification

  Class I

  • Unstable angina secondary to increased oxygen demand such as fever, tachycardia, thyrotoxicosis or anaemia

  Class II

  • Unstable angina secondary to decreased oxygen supply such as hypoxia, anaemia or hypotension

  Class III

  • Unstable angina at rest; subdivided into A (not previously treated), B (treated but recurrent) and C (post-infarction)
• What are the DDx of unstable angina?


  MI

  GORD

  MSK Chest Pain
• How can MI be differentiated from UA?


  Troponin in blood & ECG features
• How can GORD be differentiated from UA?


  Relief of symptoms with antacids, absence of exercise-induced symptoms & lack of response to GTN
• How can MSK chest pain be differentiated from UA?


  • Chest pain is often sharp & localised, increasing with movement or deep breathing
  • Can be distinguished by absence of exertional symptoms, lack of response to GTN & reproducibility with physical manoeuvres
• What are the modifiable RFs of ACS?

  Smoking

  Obesity

  Diet

  Lack of exercise

  High cholesterol

  HTN

  Drugs use (esp cocaine)

  (Diabetes)
• What are the non-modifiable RFs of ACS?

  Older age

  Male

  Ethnicity

  FHx

  (Diabetes)
• What are the signs & symptoms of UA?


  Chest pain (at rest, with minimal exertion or increasing frequency)

  • often described as pressure/heaviness/squeezing in centre of chest
  • can radiate to neck, jaw, epigastrium or arms

  SOB

  • due to impaired ventricular function

  Syncope

  • due to reduction in CO in severe angina episodes

  Nausea & vomiting

  • mediated by vagal stimulation

  Sweating

  • increased sympathetic activity during episodes of UA
• What is a physical examination like in UA?

  Normal

  BUT during episodes of angina there may be signs of myocardial ischaemia (S4, hypotension, or transient mitral regurgitation)

  Pts can also have signs of CHF -> if LV function is signif impaired

  Pallor & cool extremities can be seen in severe cases -> due to reduced CO
• Who are atypical presentations of ACS seen in?

  Elderly

  Women

  Diabetics
• What are the atypical symptoms of UA?

  May experience dyspnoea or fatigue as primary symptom (rather than chest pain)

  Other atypical symptoms

  • epigastric discomfort
  • indigestion-like symptoms
  • isolated diaphoresis
• What are the complications of UA?

  Acute MI

  • results from prolonged ischaemia -> irreversible myocardial cell death

  Arrhythmias

  • common in UA
  • due to ischaemia-induced electrical instability in myocardium
• What is the immediate management of UA & NSTEMI?

  Morphine

  Oxygen

  Nitrates

  Aspirin 300mg

  Ticagrelor 180mg

  Also fondaparinux (2.5 mg SC) -> if eGFR > 20 & no evidence of bleeding

  Urgent coronary angiography +/- PCI in pts who are clinically unstable
• Troponin is a non-specific marker, meaning that a raised troponin does not automatically imply acute coronary syndrome.
• Other than ACS, what can also raise troponin levels?


  Chronic kidney disease

  Sepsis

  Myocarditis

  Aortic dissection

  PE
• What investigations should be done for ACS?


  Obs

  ECG

  FBC

  U&Es

  LFTs

  Amylase

  CRP

  Troponin I & T

  HbA1c

  Lipids

  CXR

  Angiography

  Echocardiogram
• What are the differences in ECG findings in ACS?


  UA -> can be normal OR can have some ST depression or T wave inversion

  NSTEMI -> ST depression or T wave inversion

  STEMI -> ST elevation or new LBBB
• What are the differences in troponin levels in ACS?


  UA -> normal

  NSTEMI -> raised

  STEMI -> raised
• What is the initial management for all ACS?


  CPAIN

  Call an ambulance

  Perform an ECG

  Aspirin 300mg

  IV morphine

  Nitrate (GTN)
• What is the GRACE risk score?


  Tool used to predict 6 month mortality in pts following initial ACS -> guides further management decisions

  
• What is used in secondary prevention of ACS?


  Cardiac rehabilitation

  Drug therapy (ACE inhibitor, beta blockers, dual antiplatelet therapy, statin, spironolactone)
• Pathophys of UA


  Atherosclerosis → plaque disruption (often due to physical exertion/stress, can be spontaneous) → platelet adhesion to sub-endothelial collagen → platelet activation → platelet aggregation → fibrin clot formation → thrombus partially blocks coronary artery → myocardial ischaemia → cells switch to anaerobic metabolic → generation of lactic acid → anginal chest pain
• What are the signs & symptoms of ACS?

  Chest pain (at rest, with minimal exertion or increasing frequency)

  SOB

  Syncope

  Nausea & vomiting

  Sweating

  Pallor

  Atypical symptoms

  • Epigastric pain
  • Indigestion
  • Isolated diaphoresis
• What are the complications of UA?


  Acute MI

  Arrhythmias
• Pathophys of NSTEMI


  Plaque formation → platelet adhesion → platelet aggregation → partial occlusion of coronary artery
• What are the DDx of NSTEMI?


  STEMI

  UA

  Aortic dissection

  PE

  Peptic ulcer disease

  Acute pericarditis

  Oesophageal spasm

  Costochondritis

  Panic attack

  Stable ischaemic heart disease

  Myocarditis

  Acute cholecystitis

  Boerhaave syndrome

  Brugada syndrome

  Acute stress cardiomyopathy
• Pathophys of STEMI


  Plaque formation → platelet adhesion → platelet aggregation → complete occlusion
• What are the DDx of STEMI?


  UA

  NSTEMI

  Aortic dissection

  PE

  Pneumothorax

  Pneumonia

  Pericarditis

  Myocarditis

  GORD

  Oesophageal spasm

  Anxiety or panic attack
• What are the signs & symptoms of STEMI?


  Chest pain (may radiate)

  SOB

  Pallor

  Diaphoresis

  Nausea & vomiting

  Palpitations

  Reduced consciousness

  Hypotension

  Abnormal breath sounds

  Additional heart sounds

  Symptoms at rest or on minimal exertion

  Lasts > 20 mins

  Often accompanied by other symptoms

  Poor GTN relief
• What is the treatment of STEMI?


  MONA

  Morphine

  O2 (if required)

  Nitrate (GTN)

  Aspirin 300mg

  Place on cardiac telemetry

  PCI -> should occur within 120 mins of presentation (if unable to get PCI within 120 mins -> can get fibrinolysis)
• When is CABG indicated?


  Coronary angiogram shows > 50% stenosis in the presence of any of the following:

  • Severe angina → unresponsive to medical therapy
  • Marked ST depression on exercise ECG
  • Left main stem stenosis
  • Severe triple vessel disease
  • Angina with LV dysfunction
• Why might diabetics have silent MI?


  neuropathy in ANS → cannot detect pain → silent MI → harder to treat & diagnose

  Should have lower threshold for troponin tests
• Aortic dissection can present with neurological complications.