Acute Coronary Syndrome

Question 1

Pathophysiology of acute coronary syndrome

Answer 1

• result of a thrombus from an atherosclerotic plaque blocking a coronary artery
• when a thrombus forms in a fast flowing artery it is made up mostly of platelets
• this is why we use anti-platelet medications: such as aspirin, clopidogrel and ticagrelor

Question 2

Right Coronary Artery (RCA)curves around the right side and under the heart and supplies the:

Answer 2

• Right atrium
• Right ventricle
• Inferior aspect of left ventricle
• Posterior septal area

Question 3

Circumflex Arterycurves around the top, left and back of the heart and supplies the:

Answer 3

• Left atrium
• Posterior aspect of left ventricle

Question 4

Left Anterior Descending (LAD)travels down the middle of the heart and supplies the:

Answer 4

• Anterior aspect of left ventricle
• Anterior aspect of septum

Question 5

3 types of Acute Coronary Syndrome:

Answer 5

• unstable angina
• ST elevation Myocardial Infarction (STEMI)
• Non-ST elevation Myocardial Infarction (NSTEMI)

Question 6

Clinical presentation of acute coronary syndrome

Answer 6

Central, constricting chest pain associated with:

• Nausea and vomiting
• Sweating and clamminess
• Feeling of impending doom
• Shortness of breath
• Palpitations
• Pain radiating to jaw or arms

Symptoms should continue at rest for more than 20 minutes. If they settle with rest consider angina. Diabetic patients may not experience typical chest pain during an acute coronary syndrome. This is often referred to as a “silent MI”.

Question 7

Investigations/diagnosis of acute coronary syndromes?

Answer 7

Perform an ECG:
- If there is ST elevation or new left bundle branch block the diagnosis is STEMI

• If there is no ST elevation then perform troponin blood tests
  • raised troponin levels and other ECG changes (ST depression or T wave inversion or pathological Q waves) the diagnosis is NSTEMI
  • if tropinin levels are normal and ECG does not show pathological changes the diangosis is either unstable angina or another cause such as musculoskeletal chest pain

PLUS:
- Chest Xray
- CT coronary angiogram

Question 8

Acute STEMI Treatment

Answer 8

Patients with STEMI presenting within 12 hours of onset should be discussed urgently with local cardiac centre for either:

• Primary PCI(if available within 2 hours of presentation)
• Thrombolysis(if PCI not available within 2 hours)

The local cardiac centre will advise about further management (such as further loading with aspirin and ticagrelor).

Question 9

Percutaneous Coronary Intervention (PCI)involves ?

Answer 9

putting a catheter into the patient’s brachial or femoral artery, feeding that up to the coronary arteries under xray guidance and injecting contrast to identify the area of blockage. This can then be treated using balloons to widen the gap or devices to remove or aspirate the blockage. Usually a stent is put in to keep the artery open.

Question 10

Thrombolysis involves?

Answer 10

injecting a fibrinolytic medication (they break downfibrin) that rapidly dissolves clots. There is a significant risk of bleeding which can make it dangerous. Some examples of thrombolytic agents are streptokinase ,alteplase and tenecteplase.

Question 11

Acute NSTEMI treatment: BATMAN

Answer 11

B–Beta-blockers**unless contraindicated

A–Aspirin 300mg stat dose

T–Ticagrelor 180mg stat dose (clopidogrel 300mg is an alternative if higher bleeding risk)

M–Morphine titrated to control pain

A –Anticoagulant: Fondaparinux (unless high bleeding risk)

N–Nitrates (e.g. GTN) to relieve coronary artery spasm

Give oxygen only if their oxygen saturations are dropping (i.e. <95%).

Question 12

GRACE score to assess for PCI in NSTEMI:

Answer 12

This scoring system gives a 6-month risk ofdeathorrepeat MIafter having an NSTEMI:

• <5% Low Risk
• 5-10% Medium Risk
• > 10% High Risk

If they are medium or high risk they are considered for early PCI (within 4 days of admission) to treat underlying coronary artery disease.

Question 13

Complications of acute coronary syndrome?

Answer 13

D–Death
R–Rupture of the heart septum or papillary muscles
E–Edema (heart failure
A - Arrhythmia and Aneurysm
D - Dressler’s syndrome

Question 14

What is Dressler’s syndrome?

Answer 14

This is also calledpost-myocardial infarction syndrome. It usually occurs around2-3 weeks after an MI. It is caused by alocalised immune responseand causespericarditis(inflammation of thepericardiumaround the heart). It is less common as the management of ACS becomes more advanced.

Question 15

How does Dressler’s syndrome present?

Answer 15

It presents withpleuriticchest pain, low grade fever and apericardial rubon auscultation. It can cause apericardial effusionand rarely apericardial tamponade(where the fluid constricts the heart and prevents function).

Question 16

How can Dressler’s syndrome be diagnosed?

Answer 16

A diagnosis can be made with anECG(global ST elevationandT wave inversion),echocardiogram(pericardial effusion) and raisedinflammatory markers(CRPandESR).

Question 17

Management of Dressler’s syndrome?

Answer 17

Management is withNSAIDs(aspirin/ibuprofen) and in more severe casessteroids(prednisolone). They may needpericardiocentesisto remove fluid from around the heart.