ACUTE CORONARY SYNDROMES

Objectives

Decide on the correct management of patients with acute coronary syndrome based on the findings of a clinical history, examination and relevant test results such as an ECG

Demonstrate ability to interpret clinical findings in people presenting with acute coronary syndrome

Choose the correct evidence-based management for a number of cases of acute coronary syndrome.

Case 1: History

A 57 year old man has intermittent chest pain of

10-20 minutes duration with minimal exertion

Up to 5 times a day over the past 1 week. A

particularly prolonged episode precipitated his

presentation to hospital. He had a 30 pack year

history of smoking, hypertension,hyperlipidaemia and gout.Current medications include aspirin, atorvastatin + NSAIDs

Primary presentations suggesting ACS

(1) New onset angina markedly limiting physical activity

(2) Siesta or rest angina >20 minutes duration

(3) Worsening angina more frequent, longer duration or occurs with less exertion than previously

Atypical presentations of ACS

(1) Elderly + diabetes(2) Dyspnoea, syncope or

confusion/delirium

Case 1 : Examination + Investigations

He was afebrile, heart rate 65 beats per minute, a

blood pressure of 175/110 mm Hg and normal

oxygen saturation . No cardiac murmurs were

heard and no clinical signs of cardiac failure.

An initial serum troponin level was elevated at

0.93 μg/L.What is the ECG finding?

ECG

Answer ECG

A 2 mm ST segment depression in II, III, a VF and

V5-V6

Differences Unstable angina vs NSTEMI vs STEMIUnstable angina

NSTEMI STEMI

Ischaemic symptoms

+ + + ( severe onset central chest pain with dyspnoea + diaphoresis)

Elevation troponin or CKMB

___ +/-( may not be detectable hours after presentation)

+

ECG changes( ST segment depression , transient elevation or new T wave inversion

___ ___ ST elevation Q waves+/-(depends size infarct, duration occlusion, extent collateral vessels maintain myocardial viability during occlusion)

Indications coronary angiography

Suspicion of a STEMI(1) Ischaemic symptoms + elevation

troponins + ECG changes(2) Left circumflex coronary artery

occlusion (ongoing chest pain + nonspecific lateral ST-T wave changes + not a significant ST elevation + masquerading as a NSTEMI)

How do you estimate the risk?RIS2K A2 TIMI risk score: 30 day mortality

(1) Three Risk factors at least for heart disease (hypertension, diabetes, dyslipidaemia, smoking,positive family history)

(2) Increasing age >65 years(3) Prior coronary Stenosis of > 50%(4) Serum cardiac biomarkers elevated(5) eKg admission : ST-segment deviation (6) Angina in previous 24 hours(at least 2

episodes)(7) Aspirin use in prior seven days (probably a

marker for more severe coronary disease

TIMI + ESSENCE trials

Score Risk of death

0 to 2 low

3 or 4 intermediate

5 to 7 high

How do you relieve the ischaemic pain? Part 1

(1) Oxygen +glyceryl trinitrate (intravenous glyceryl trinitrate : in patients with persistent pain, hypertension or heart failure). Nitrates used with caution right ventricular infarction, hypotension and severe aortic stenosis.

(2) Intravenous morphine sulfate at an initial dose of 2 to 4 mg, with increments of 2 to 8 mg repeated at five to 15 minute intervals for the relief of chest pain and anxiety

How do you relieve the ischaemic pain? Part 2

(1) Beta blockers within 24 hours of an acute myocardial infarction is recommended , not recommended acutely in haemodynamic instability, cardiogenic shock or heart failure. Intravenous beta blockers should be used only inpatients without contraindications who have ongoing rest pain plus hypertension and tachycardia.

(2) Antiplatelet and antithrombotic therapy: refer next slide

What antiplatelet + antithrombic therapy is used? Part 1

(1) Uncoated aspirin ASAP the onset of symptoms (300 mg) unless this is absolutely contraindicated. The tablet should be chewed to establish a high blood level quickly

(2) Clopidogrel with aspirin: 20% reduction in ischaemic endpoints (including death and myocardial infarction) when compared with aspirin alone. Seen in all subgroups in CURE trial, ( elderly + patients not revascularised)

What antiplatelet + antithrombic therapy is used? Part 2

(1) Prasugrel : potential advantage increased potency over clopidogrel when used in patients with acute coronary syndromes undergoing percutaneous coronary intervention (PCI), especially with STEMI + who have diabetes.

(2) Intravenous glycoprotein IIb/IIIa inhibitors (abciximab and eptifibatide )in the prevention of ischaemic complications associated with PCI well documented in patients with acute coronary syndromes. Combination clopidogrel + glycoprotein IIb/IIIa inhibitor reasonable in patients at high risk with recurrent ischaemic discomfort or delay in angiography is anticipated

What antiplatelet + antithrombic therapy is used? Part 3

Invasive approach, UFH + low molecular weight heparin (enoxaparin) viable options.

The advantages of enoxaparin (i) lower incidence of heparin-associated

thrombocytopenia,(ii) ease of administration without the need for

monitoring, (iii) lesser degree of platelet activation. (iv) fewer recurrent nonfatal myocardial infarction A

Disadvantage inability to reverse the anticoagulation ofenoxaparin with protamine

What antiplatelet + antithrombic therapy is used? Part 4

Direct thrombin inhibitors : bivalirudin (In the

Acute Catheterization + Urgent Intervention

Triage Strategy (ACUITY) trial of moderate +high risk acute coronary syndrome: bivalirudin compared with UFH + glycoprotein IIb/IIIainhibitor. The clinical outcomes similarin terms of ischaemic events but the

bivalirudingroup had significantly less bleeding.

When do we do invasive treatment?

(1) Patients with an acute coronary syndrome who meet intermediate or high-risk criteria (TIMI Risk score > 2) (2) Optimal timing of intervention not been defined, but likely between 4 – 48 hours of admission(3) PCI is most often performed in patients with an

appropriate lesion.(4) CABG is usually preferred for the treatment of

patients with left main coronary artery or triple vessel disease, or double Vessel disease involving the left anterior descending coronary artery in patients with left ventricular dysfunction or diabetes

Goals of subsequent management Part 1

(1) Prevention of recurrent ischaemic events with long-term oral antiplatelet therapy. Aspirin recommended lifelong + clopidogrel for at least one month (for at least 12 months or

lifelong in selected cases).(2) Prevention of recurrent ischaemia+ life-

threatening ventricular arrhythmias with beta blockers.

(3) Reduction of cholesterol levels with a statin to prevent or slow disease progression + prevent cardiovascular events (the target level for total cholesterol is below 4.0 mmol/L + LDL, below 2.0 mmol/L).

Goals of subsequent management Part 2

(4) Long-term oral anticoagulation (warfarin) is not recommended after an acute coronary syndrome but should be considered if left ventricular thrombus or chronic atrial fibrillation is present to prevent thromboembolisation. In this instance, so called ‘triple therapy’ may be recommended until clopidogrel is ceased (continue aspirin and warfarin).

(5) Possible use of an ACE inhibitor in patients at increased risk, in particular those with diabetes, heart failure or left ventricular ejection fraction < 40%. Care should be exercised in those with renal impairment (especially acute renal impairment).

Angiotensin receptor blockers are considered a reasonable alternative