Acute Coronary Syndrome

Acute Coronary Syndrome
Pathophysiology, Investigations & Management

including Case Example
Presentation written and delivered by:

Dr Amalia V Stavropoulos, BA MBBS
Internal Medicine Trainee (Severn)
Presentation Outline
● Broad overview of acute coronary syndrome

■ Classification
■ Pathophysiology
■ Investigations
■ Management
● Case Example (interactive)
● Feedback
Definition and Classification
● ACS can be defined as a varying degree of coronary artery

luminal obstruction which results in
○ decreased blood flow and
○ subsequent ischaemia to the territory of the affected
vessel.
● Classification:
1) Unstable Angina
2) Non-ST Elevation Myocardial Infarction (NSTEMI)
3) ST Elevation Myocardial Infarction (STEMI)
Classification explained
Unstable Angina NSTEMI STEMI

Can be: Myocardial necrosis that tends to Myocardial necrosis that tends to
• New exertional angina occur from coronary artery occur following plaque rupture and
• Angina that was previously stenosis rather than full occlusive thrombosis with full occlusion of a
stable but now occurs with less thrombosis. coronary artery.
physical exertion
• Angina that occurs at rest
• Cardiac markers negative • Positive/elevated cardiac • Positive/elevated cardiac
• ECG lacks ST segment markers markers
elevation • ECG lacks characteristic ST • ECG demonstrates ≥ 1 mm ST
segment elevation but other segment elevation in 2 or more
features may be present, such as contiguous leads or new LBBB
ST segment depression or T wave
inversion.
Pathophysiology
• Most commonly due to thrombus formation over an

eroded, fissured, or ruptured atheromatous plaque
an atherosclerotic coronary artery.
• Partial or full occlusion the coronary artery.
Be aware: there are many non-atherosclerotic aetiologies of ACS. These
include coronary artery embolism, dissection, and spasm.
Relevant Anatomy
Circumflex Artery (Cx)

Right Coronary Artery • Posterolateral left
(RCA)
ventricle
• Right atrium &
ventricle
• SA and AV node Left Anterior
Descending (LAD)
• Left ventricle
Clinical features
• Chest pain or discomfort

• Described as heaviness, tightness, pressure, squeezing
• Pain radiating to arms, jaw, epigastrium
• Nausea and vomiting
• Diaphoresis
• Syncope or pre-syncope
• Shortness of breath
• Indigestion
Differential Diagnosis
• Arrhythmia • Aortic dissection

• Pericarditis • GORD
• Pneumonia • Oesophageal spasm
• Pulmonary Embolism • Costochondritis
• Pneumothorax • Chest trauma (ie, rib
fracture)
Investigations
• Primary investigations:
• Serial ECG’s
• Cardiac biomarkers
• Coronary angiography
• Investigations to consider:
• Chest Xray
• D-dimer
ECG territories
Normal ECG
Example of STEMI
Example of STEMI
Role of Troponin
• Troponin has three subunits - TnC, TnI, and TnT.

• Regulate cardiac contraction by blocking actin-myosin
crossbridge formation.
• Action potential causes release of
calcium ions from sarcoplasmic
reticulum. Calcium binds to the
troponin complex, changing its shape
and releasing it to allow for actin-
myosin crossbridge formation and
hence contraction.
Role of Troponin
• cTnI and cTnT are used as

markers of cardiac damage.
• Rise 3-6 hours after onset of

chest pain in NSTEMI/STEMI
and continue to increase to a
peak between 16-30 hours.
Case Example - History
History Observations
41-year-old gentleman, presented • HR: 88
with left-sided chest and jaw pain. • BP: 142/87 mmHg
• Recent dental infection treated • RR: 16
with 5-day course of antibiotics • SpO2: 98% on air
• Family History - No ischaemic • Temp: 36.8 degC
heart disease
Past Medical History Examination

• No cardiac murmur
• Type II Diabetes Mellitus
• Warm peripheries
• Hypertension
• Chest clear
• Obesity
• Abdomen soft
• Current smoker of 10-20
• No leg oedema
cigarettes daily
Case Example - ECG
Case Example - Troponin
Management (for STEMI)
• Immediate Management
• Dual anti-platelet therapy
- aspirin 300 mg + clopidogrel 300 mg STAT
• Subcutaneous anti-coagulant
- fondaparinux 2.5 mg
• Consider oxygen if Sats <94%
• Morphine, anti-emetics, and GTN
• Proceed to primary percutaneous coronary intervention (pPCI)
- Can be performed within 12 hours of symptom onset with must be within 120 mins of when
fibrinolysis could have been given
• Fibrinolysis if pPCI cannot be achieved within 120 minutes
• See NICE guidance Flow Chart (link provided in comment box below).
Primary PCI
• Performed by an interventional cardiologist in the

cardiac catheterisation lab (“cath lab”).
• Used to open up a blocked coronary artery to restore
blood flow.
• Access is obtained via the radial or femoral artery.
• Radio-opaque dyes and XRays are employed to
identify the culprit lesion.
• Once the lesion is identified, a balloon can be inflated
to open up the lesion and a stent can be implanted to
keep the vessel patent.
• Once a stent is deployed, the patient will require
lifelong aspirin treatment.
Case pPCI Outcome
Long term management
• If stent deployed, one-year of dual anti-platelet therapy

- Then, lifelong aspirin monotherapy
• Beta blocker (ie, bisoprolol)
• ACE inhibitor (ie, ramipril)
• HMG-CoA Reductase Inhibitor (ie, atorvastatin)
• Consider aldosterone antagonist (ie, eplerenone) if EF <40%
• Nitrates (ie, GTN spray)
• Risk factor reduction and lifestyle changes (ie, BP and diabetes control)
Unstable Angina & NSTEMI Management
• Initially, offer loading dose aspirin + fondaparinux

• Then, assess risk of future adverse cardiovascular events using the GRACE
score
• If risk of 6-month mortality found to be at least 1.5%, load with
clopidogrel as well
• If found to be intermediate to high risk (>3%) perform coronary
angiography within 96 hours of admission
• See NICE guidance Flow Chart (link provided in comment box below).
Complications
• Cardiac arrest and death

• Myocardial rupture
• Heart failure
• Dressler’s syndrome
• Arrhythmias
Key Messages
• Substernal chest pain is the classical presenting feature of ACS

• Understand the differences among unstable angina vs NSTEMI vs STEMI
• Be able to identify the affected coronary vessel and corresponding cardiac
territory of STEMI
• For STEMI patients, “time is muscle” – aim pPCI within 120 minutes
• Patients who cannot have pPCI within 120 mins and have no
contraindications should proceed to fibrinolysis
• Know the pharmacological management of ACS
• Appreciate the role of the GRACE score
References
(1) NICE guidance on ACS

https://www.nice.org.uk/guidance/conditions-and-diseases/cardiovascular-conditions/acute-coronary-s
yndromes
(2) BNF/NICE resource on ACS management

https://bnf.nice.org.uk/treatment-summary/acute-coronary-syndromes.html
(3) Life in the Fast Lane resource on acute coronary syndromes

https://litfl.com/acute-coronary-syndromes/
(4) Geeky Medics resources on ACS (great for OSCE practice)

https://geekymedics.com/acute-coronary-syndrome-acs-emergency-management-abcde/
https://geekymedics.com/chest-pain-history/
(5) GRACE score calculator

https://www.mdcalc.com/grace-acs-risk-mortality-calculator
Feedback
Please complete your feedback forms.
a.stavropoulos@doctors.org.uk

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Pathophysiology, Investigations & Management

Presentation written and delivered by:

● Broad overview of acute coronary syndrome

● Case Example (interactive)

● ACS can be defined as a varying degree of coronary artery

Unstable Angina NSTEMI STEMI

• Most commonly due to thrombus formation over an

Circumflex Artery (Cx)

• Chest pain or discomfort

• Arrhythmia • Aortic dissection

• Troponin has three subunits - TnC, TnI, and TnT.

• cTnI and cTnT are used as

• Rise 3-6 hours after onset of

Past Medical History Examination

• Performed by an interventional cardiologist in the

• If stent deployed, one-year of dual anti-platelet therapy

• Initially, offer loading dose aspirin + fondaparinux

• Cardiac arrest and death

• Substernal chest pain is the classical presenting feature of ACS

(1) NICE guidance on ACS

(2) BNF/NICE resource on ACS management

(3) Life in the Fast Lane resource on acute coronary syndromes

(4) Geeky Medics resources on ACS (great for OSCE practice)

(5) GRACE score calculator

Please complete your feedback forms.

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