Acute Coronary Syndromes Flashcards
What can cause acute coronary syndrome?
Unstable angina
Non-ST elevation myocardial infarction
ST elevation myocardial infarction
What are the possible physiological causes of acute coronary syndrome?
Atherosclerosis plaque rupture or erosion
Superimposed platelet aggregation and thrombosis
Vasospasm and vasoconstriction
Subtotal or transient total occlusion of vessel
What are the goals of ACS therapy?
Increase myocardial oxygen supply
Decrease myocardial oxygen demand
How is myocardial oxygen supply increased?
Through coronary vasodilation
How is myocardial oxygen demand decreased?
Decreased heart rate
Decreased blood pressure
Decreased preload or myocardial contractility
What is the most likely cause of ACS in patients with STEMI?
Coronary thrombus occluding the infarct artery
How are patients with STEMI treated?
If no percutaneous intervention within 2 hours then thrombolysis
How do thrombolytic agents work?
They convert plasminogen into plasmin, a natural fibrinolytic agent
What does plasmin do?
Lyses clots by breaking down the fibrinogen and fibrin
What are the two categories of fibrinolytics?
Fibrin-specific agents
Non-fibrin-specific agents
Name some fibrin-specific agents
Alteplase
Reteplase
Tenecteplase
Name a non-fibrin-specific agents
Streptokinase
When would thrombolytic agents not be used?
Prior intracranial haemorrhage Known structural cerebral vascular lesion Known malignant intracranial neoplasm Ischaemic stroke within 3 months Suspected aortic dissection Active bleeding Bleeding diathesis Significant close-head/facial trauma within 3 months
What should be used with thrombolysis when possible?
Aspirin
If no STEMI what is the treatment of ACS?
Aspirin Trigagrelor/Clopidogrel Fondapurinux/LMW heparin Intravenous nitrate Analgesia Beta blockers Statin Prasugrel G IIb IIIa receptor blocker
What is acute coronary syndrome?
Any sudden cardiac event suspected or proven to be related to a problem with the coronary arteries
What is the worse possible outcome of ACS?
Sudden cardiac death
What is the only type of ACS that is treated with thrombolytics?
STEMI
How is NSTEMI managed?
Aspirin PCI CABG Heparin Fondaparinux Statins Beta blockers Clopidogrel Prasugrel Ticagrelor Ticlopidine Cilostazol G IIb IIIa receptor
Why are anti platelet agents important?
The formation of platelet aggregates are important in the pathogenesis of angina, unstable angina and acute MI
What does Aspirin do?
Aspirin is a potent inhibitor of platelet thromboxane A2 production
What does thromboxane do?
Stimulates platelet aggregation and vasoconstriction
When can Aspirin be used?
In acute MI
In unstable angina
In secondary prevention
What can happen at high dose aspirin?
GI bleed
Is high dose aspirin more effective than low dose?
No
What does Clopidogrel do?
Inhibits ADP receptor activated platelet aggregation
Prodrug
In preventative medicine what should Aspirin be taken with?
Clopidogrel
If Clopidogrel is not available what can be used instead of it?
Prasugrel
Give examples of low molecular weight heparins
Enoxaparin
Dalteparin
Tinzeparin
Fondaparinux
Is Enoxaparin or Fondaparinux preferable?
Fondaparinux
What do Glycoprotein IIb/IIIa receptor inhibitors do?
Block platelet aggregation by inhibiting fibrinogen binding to conformationally activated form of GPIIb/IIIa receptor
What is the major adverse effect of Glycoprotein IIb/IIIa receptor inhibitors?
Bleeding
When are beta blockers used?
In the treatment of MI
Secondary prevention in survivors of an acute MI
Give examples of beta blockers.
IV atenolol
Metoprolol
When should beta blockers be avoided?
In patients with symptoms possibly related to coronary vasospasm or cocaine use
What causes a STEMi?
Complete coronary occlusion
What causes a NSTEMI?
Partial coronary occlusion
What is part of chromic ischaemic heart disease?
Stable angina
What is the physical difference in a STEMI and NSTEMI?
Partial thickness damage of heart muscle in NSTEMI but full thickness damage of heart muscle in STEMI
On an ECG what difference is there between NSTEMI and STEMI?
ST elevation
Q wave in STEMI
What type of MI is a STEMI?
Transmural MI
What type of MI is a NSTEMI?
Subendocardial MI
How is an MI diagnosed?
Positive cardiac biomarkers
Symptoms of ischaemia
ECG changes
Evidence of coronary problems
What are the non-cardiac cause of troponin rise?
Pulmonary embolism
Sepsis
Renal failure
Sub-arachnoid haemorrhage
What are the different classes of MI?
Type 1, 2, 3, 4a, 4b and 5
What are the possible causes of an MI?
Coronary vasospasm Coronary dissection Embolism in coronary artery Inflammation of coronary arteries Radiotherapy to chest can cause fibrosis and stenosis of coronary arteries Plaque erosion, rupture or fissuring PCI related Stent thrombosis CABG related
What are the different types of transmural MI?
Inferior Anterior Lateral Posterior Septal
What causes an inferior MI?
Total occlusion of the right coronary artery
What causes an anterior MI?
Total occlusion of the left anterior descending coronary artery
What causes a lateral MI?
Total occlusion of the circumflex coronary artery
What are the possible reperfussion therapies?
Mechanical - PCI
Pharmacological
What does GTN do?
Vasodilator
What do opiates do?
Help relieve anxiety
Helps venodilate
Pain relief
Give an example of an opiate
Morphine
Give an example of a beta blocker
Bisoprolol
Give an example of a statin
Simvastatin
Give an example of an ACE inhibitor
Ramipril
What are the risks of coronary angiography or angioplasty or stenting?
Bleeding Blood vessel damage MI Coronary perfusion Stroke Dye can affect kidney - contrast nephropathy
What are the complications that can follow an MI?
Arrhythmia Mechanical Cariogenic shock Myocardial rupture Death
What are the mechanical complications of an MI?
Valve dysfunction
Acute ventricular septal defect
What therapy is required after PCI or CABG?
Dual anti-platelet therapy for 12 months
What are the long term complications of PCI and CABG?
Increased risk of further MI
Cardiac failure
