Acs

Front 1

Role of platelets in STEMI

Back 1

Platelets play a pivotal role in the pathogenesis of acute coronary artery thrombosis. Spontaneous atherosclerotic plaque rupture or mechanical plaque disruption during catheterization of an atheromatous coronary artery exposes subendothelial proteins to the circulating blood which leads to platelet adhesion, activation, and aggregation. Release of tissue factor activates the coagulation system and leads to thrombin generation. Thrombin converts fibrinogen to fibrin and further activates platelet, leading to the recruitment of additional platelets to the site of vascular injury. Activated platelets provide a phospholipid surface for the assembly of pro-coagulant clotting factors. The resulting intracoronary thrombus can obstruct blood flow, causing myocardial ischemia and the clinical manifestations of STEMI.

Front 2

Antiplatelet options in STEMI

Back 2

- All patients with STEMI should be commenced on dual anti platelet agents, aspirin + clopidogrel unless contraindicated

- Loading dose if not already on daily aspirin/clopidogrel unless high bleeding risk

- Continue Aspirin life long

- Continue clopidogrel (ADP receptor blocker) at maintenance dose for 1 month if no PCI

- Continue clopidogrel 1 month after thrombolysis

- Continue clopidogrel at maintenance dose for 1 month if bare metal stent inserted (BMS) , and 3-6 months if drug eluding stent inserted (3 months for sirolimus, 6 months for paclitaxel). In patients who are not at high risk for bleeding, it is reasonable to continue clopidogrel for 12 months or more to prevent late stent thrombosis. For STEMI patients taking clopidogrel in whom CABG is planned, the drug should be withheld for at least 5 days and preferably for 7 days unless the urgency for revascularization outweighs the risks of bleeding.

Front 3

Primary PCI, Rescue PCI, Elective PCI

Back 3

Primary PCI: emercency, performed while the clot is still forming, usually <12 hrs from time of presentation (ideally within 2hrs of presentation)

Rescue PCI: Attempting to revascularise heart muscle that has been starved for sometime...either because of delayed presentation or because of failed thrombolysis. Rescue PCI is indicated immediately if PCI has failed, i.e. <50% resolution of ST segment elevation in 60 mins. Emergency PCI indicated for recurrent schema or evidence of schema after thrombolysis. Angiography with view. Angiography with view to revascularisation is indicated after successful fibrolysis (within 3-24 hrs). Routine PCI of totally occluded artery >24hrs after symptom onset in patients without signs of ischemia regardless of whether thrombolysis was administered or not is not recommended

Elective PCI: non urgent PCI based on identifying high risk individuals (e.g. with stress ECG, echoes or sestamibis)

Front 4

DES vs BMS

Back 4

If there are no contraindications to dual anti platelet therapy and the patient is likely to be compliant then a drug eluding stent should be chosen over bare metal stent

Front 5

Options for dual anti platelet therapy

Back 5

1. Clopidogrel
2. Ticagrelor
3. Prasugrel

Front 6

Anticoagulant used in STEMI

Back 6

Recommended until revascularisation is performed

1. Unfractionated heparin (aim for activated clotting time of 200-300s if Gp2/3a inhibitors are used or ACT of 300-350s if tirofiban/abciximab are not used)
2. Bivalirudin
3. Enoxaparin

Front 7

Fibrin specific agents used for thrombolyis

Back 7

Second generation, fibrin specific agents available as bolus

Tenecteplase
Alteplase
Reteplase

Streptokinase should not be used in Aboriginal patients (because of high rates of skin infections, likely to have high titres of streptococcal antibodies) or patients with previous exposure to the drug. Streptokinase is associated with higher mortality rates

Front 8

TIMI bleeding criteria

Back 8

TIMI: Thrombolysis in Myocardial Infarction

Criteria developed in TIMI trials to classify major and minor haemorraghic episodes in STEMI patients treated with fibrinolytic drugs

Major:
1. Any intracranial bleeding
2. Clinically overt haemorrhage resulting in drop of Hb >/= 5g/dL or more than 10% decrease in haematocrit
3. Fatal bleeding (resulting in death within 7 days)

Minor:
1. Clinically overt bleeding resulting in Hb drop of 3-5g/dL or >/=10% drop in haematocrit
2. Overt signs of bleeding that does not meet above criteria that requires intervention, prolonged hospitalisation or investigation

Minimal:
1. Overt bleeding that does not meet above criteria
2. Overt sign of haemorrhage associated with Hb drop < 3g/dL or drop in haematocrit less than 9%

Front 9

Choice of repercussion in STEMI

Back 9

PCI superior to thrombolyis however choice depends on access

- If patient presents within 1hr of symptoms, then PCI should be performed in 60 mins, else consider thrombolysis

- If patients presents within 1-3hrs, PCI should be performed within 90mins else consider thrombolysis

- For patients presenting within 3-12 hrs of symptoms, PCI should performed within 2hrs (including transport time) else consider thrombolysis

- Reperfusion is not routinely recommended > 12hrs after symptom onset if asymptomatic and haemodynamically stable

- Fibrinolysis should be given within 30 mins of presentation

Front 10

Need for dual anti platelet agents in ACS

Back 10

All patients with NSTEMI should be commenced on aspirin. Patients should undergo risk stratification and high risk patients should also have clopidogrel.

Front 11

Medical management of ACS

Back 11

1. Any patient with ACS (unstable angina, NSTEMI, STEMI) should be commenced on SAAB (Statin, Ace Inhibitor, Aspirin and Beta Blocker)

2. AICD should be considered in patients who despite optimal medical therapy, have depressed left ventricular function 6 weeks post STEMI

Front 12

Cardiac Biomarkers

Back 12

- Rise in high sensitivity troponin (I or T) suggests myonecrosis
- However troponin rise may persist for 5-14 days so may not reflect reinfarction
- Serial measurement of CK (over 48 hours) allows us to pick up reinfarction
- CK-MB is a more specific marker of cardiac damage than CK and may be used to confirm a re-infarct

Front 13

Risk Stratification of NSTEACs

Back 13

Patients with no ECG changes or positive troponins should under stress testing before discharge (if not immediately available, stress testing should be performed within 72 hours of of the index episode)

Front 14

Definition of STEMI

Back 14

Clinical symptoms consistent with ACS and ECG criteria:

1. Persistent >/= 1mm ST elevation in 2 consecutive limb leads
2. Persistent >/=2mm ST elevation in 2 consecutive chest leads
3. New LBBB

Front 15

Contraindications to Thrombolysis in STEMI

Back 15

Absolute contraindications
Risk of bleeding
• Active bleeding or bleeding diathesis (excluding menses)
• Significant closed head or facial trauma within 3 months
• Suspected aortic dissection (including new neurological symptoms)50
Risk of intracranial haemorrhage
• Any prior intracranial haemorrhage
• Ischaemic stroke within 3 months
• Known structural cerebral vascular lesion (eg, arteriovenous
malformation)
• Known malignant intracranial neoplasm (primary or metastatic)

Relative contraindications
Risk of bleeding
• Current use of anticoagulants: the higher the international
normalised ratio (INR), the higher the risk of bleeding
• Non-compressible vascular punctures
• Recent major surgery (< 3 weeks)
• Traumatic or prolonged (> 10 minutes) cardiopulmonary resuscitation
• Recent (within 4 weeks) internal bleeding (eg, gastrointestinal or urinary tract haemorrhage)
• Active peptic ulcer
Risk of intracranial haemorrhage
• History of chronic, severe, poorly controlled hypertension
• Severe uncontrolled hypertension on presentation (> 180 mmHg
systolic or > 110 mmHg diastolic)
• Ischaemic stroke more than 3 months ago, dementia, or known intracranial abnormality not covered in contraindications
Other
• Pregnancy

Front 16

Risk stratification of NSTEMI patients

Back 16

High-risk features
Presentation with clinical features consistent with acute coronary
syndromes (ACS) and any of the following high-risk features:
• Repetitive or prolonged (> 10 minutes) ongoing chest pain or discomfort;
• Elevated level of at least one cardiac biomarker (troponin or creatine kinase-MB isoenzyme);
• Persistent or dynamic electrocardiographic changes of ST- segment depression 􏰁 0.5 mm or new T-wave inversion 􏰁 2 mm;
• Transient ST-segment elevation (􏰁 0.5 mm) in more than two contiguous leads;
• Haemodynamic compromise — systolic blood pressure
< 90 mmHg, cool peripheries, diaphoresis, Killip Class > I, and/or new-onset mitral regurgitation;
• Sustained ventricular tachycardia;
• Syncope;
• Left ventricular systolic dysfunction (left ventricular ejection fraction < 0.40);
• Prior percutaneous coronary intervention within 6 months or prior coronary artery bypass surgery;
• Presence of known diabetes (with typical symptoms of ACS); or
• Chronic kidney disease (estimated glomerular filtration rate
< 60 mL/minute) (with typical symptoms of ACS).
Intermediate-risk features
Presentation with clinical features consistent with ACS and any of the following intermediate risk features AND NOT meeting the criteria for high-risk ACS:
• Chest pain or discomfort within the past 48 hours that occurred at
rest, or was repetitive or prolonged (but currently resolved);
• Age >65 years;
• Known coronary heart disease — prior myocardial infarction with left ventricular ejection fraction 􏰁 0.40, or known coronary lesion more than 50% stenosed;
• No high-risk changes on electrocardiography (see above);
• Two or more of the following risk factors: known hypertension,
family history, active smoking or hyperlipidaemia;
• Presence of known diabetes (with atypical symptoms of ACS);
• Chronic kidney disease (estimated glomerular filtration rate < 60 mL/minute) (with atypical symptoms of ACS); or
• Prior aspirin use.
Low-risk features
Presentation with clinical features consistent with an acute coronary syndrome without intermediate-risk or high-risk features. This
includes onset of anginal symptoms within the last month, or worsening in severity or frequency of angina, or lowering of anginal threshold.

Front 17

Approach to management of NSTEMI

Back 17

Low risk features: commence on aspirin, upgrade medical management, exercise stress testing prior to discharge, discharge with cardiology follow up

Intermediate risk: exercise tress test, stress echo or sestamibi for risk re-stratification into high or low. If recurrent chest pain, features of high risk or positive stress testing need to proceed to angiography within next 48 hrs

High risk: aspirin, clopidogrel (unless PCI expected immediately or CABG within next 5-7 days), commence on heparin infusion till PCI. Consider Tirofiban infusion (GP 2b/3a inhibitors) if ongoing chest pain inspite of heparin infusion). Upgrade medical management including beta blockers, ace inhibitors and statin. All NSTEACs with high risk features should undergo PCI within 48 hours of index episode.

Front 18

TIMI risk score for STEMIs

Back 18

Score that encapsulates 14 day risk of adverse cardiac events following NSTEACS. Mnemonic is AMERICA

Age >65
Markers, elevated cardiac markers trops and CK
ECG changes, ST segment changes of at least 0.5mm
Risk factors, presence of at least 3 cardiac risk factors including HTN, smoking, diabetes, 1st degree relative with cardiac disease or mother or father with cardiac disease at age less than 65/55)
Ischemia, 2 or more episodes of chest pain in 24 hrs
CAD, known vessel disease with > 50% occlusion
Aspirin use over 7 days

Each point scores 1, a total score of 3 or more indicates high risk of cardiac event in near future and patient should undergo coronary angiography in next 48 hours

Front 19

Medical management of ACS

Back 19

1. Aspirin, all patients with ACS unless contraindicated
2. Clopidogrel, used as dual anti platelet therapy in high risk patients or in patients with stent insertion, may be used as single anti platelet agent where aspirin is contraindicated
3. Metoprolol should be commenced in all STEMI/non stemi patients. Bisoprolol, carvedilol and extended release metoprolol if evidence of heart failure
4. ACI inhibitors
5. Statins
6. Aldosterone antagonists in patients with left ventricular systolic dysfunction and symptoms of heart failure
AICD in patients with persistently depressed LV systolic function 6 weeks after STEMI despite optimal medical management