ACS & AMI - Therapy Flashcards
What does ACS stand for?
Acute coronary syndrome
What does AMI stand for?
Acute myocardial infarction
What is in the spectrum of acute coronary syndrome?
1) Unstable angina
2) Non-ST elevated myocardial infarction (NSTEMI)
3) ST elevated myocardial infarction (STEMI)
4) Sudden cardiac death
What does NSTEMI stand for?
Non-ST elevated myocardial infarction
What does STEMI stand for?
ST elevated myocardial infarction
What are some causes of acute coronary syndrome?
Atherosclerosis plaque rupture or erosion
Superimposed platelet aggregation and thrombosis
Vasospasm and vasocontriction
Subtotal or transient total occlusion of vessel
What is the goal of pharmacotherapy for acute coronary syndrome?
Increase myocardial oxygen supply
Decrease myocardial oxygen demand
How can myocardial oxygen supply be increased?
Vasodilation
How can myocardial oxygen demand be decreased?
Decrease heart rate
Decrease blood pressure
Decrease preload or myocardial contractility
What has a high likelihood of being the cause of patients with STEMI?
Coronary thrombus occluding the infarct artery
What is coronary thrombus formation usually due to?
Formation of thrombus overlying an atheromatous plaque occluding the coronary artery
What is the treatment for coronary thrombus formation?
If no percutaenous coronary intervention (PCI) within 2 hours then thrombolysis is indicated
What does PCI stand for?
Percutanous coronary intervention
What is percutaneous coronary intervention?
Non-surgical procedure that uses a catherter to place a stent to open up blood vessels in the heart that have been narrowed
What is a stent?
Thin flexible tube
What is a non-surgical procedure that uses a catheter to place a stant to open up blood vessels in the heart that have been narrowed?
Percutaneous coronary intervention
What agents are used for thrombolysis?
Serine proteases
How do serine proteases work?
Converting plasminogen to the fibrinolytic agent plasmin
How does plasmin destroy clots?
Breaks down the fibrinogen and fibrin contained in the clot
What are the 2 categories of fibrinolytics?
Fibrin specific agents
Non-fibrin specific agents
What are examples of fibrin specific agents?
Alteplase
Reteplase
Tenecteplase
What is an example of a non-fibrin specific agent?
Streptokinase systemic fibrinolysis
What are some contraindications to thrombolysis?
Prior intracranial haemorrhage
Known structural cerebral vascular lesion
Known malignant intracranial neoplasm
Ischaemic stroke within 3 months
Suspected aortic dissection
Active bleeding or bleeding diathesis
Significant closed heart head trauma or facial trauma within 3 months
What are the benefits of thrombolysis?
23% reduction in mortality
39% when used with aspirin
What can thrombolysis be used with to increase the reduction in mortality?
Aspirin
What does the medical treatment protocol if no evidence of STEMI include?
Aspirin
Tigagrelol/clopidogrel
Fondaparinux/low molecular weight heparin
Intravenous nitrate
Analgesia
Beta blockers
What does LMW stand for?
Low molecular weight
What does the management to reduce risk from NSTEMI involve?
PCI or CABG
Aspirin
Clopidogrel, prasugrel, ticagrelor, ticlopidine or cilostazol
Heparin
Fondaparinux
GIIb/IIIa receptor blockers
Statins
Beta blockers
What are examples of antiplatelet agents?
Low dose aspirin
Clopidogrel
Prasugrel
Low molecular weight heparin
Glycoprotein IIb/IIIa receptor inhibitors
What is considered to be low dose aspirin?
75-150mg
What is the formation of platelet aggregates important in the pathogenesis of?
Angina
Unstable angina
Acute myocardial infarction
How does aspirin work?
1) Potent inhibitor of platelet thromboxane A2 production
2) Thromboxane stimulates platelet aggregation and vasocontriction
What does thromboxane stimulate?
Platelet aggregation and vasocontriction
What kind of drug is clopidogrel?
Prodrug
How does clopidogrel work?
1) Irreversible inhibits the P2Y12 ADP receptor which is important in aggregation of platelets and cross linking by fibrin
2) Blockage of this inhibits platelet aggregation by blocking the activation of the GP IIb/IIIa pathway
What does clopidogrel combine to?
P2Y12 ADP receptor
What is the IIb/IIIa complex?
Receptor for fibrinogen, fibronectin and von WF, activation of this is the final common pathway for platelet aggregation and cross linking of platelets by fibrin
What should clopidogrel always be used in combination with?
Aspirin
How do some people demonstrate resistance to clopidogrel?
Low levels of CYP 2C19 which is used to activate the drug
What activates clopidogrel?
CYP 2C19
How does prasugrel work?
Just like clopidogrel, ADP receptor inhibitor
What are some different examples of low molecular weight heparin?
Enoxaparin
Dalteparin
Tinzeparin
Fondaparinux
What is a major adverse effect of most antiplatelet agents?
Bleeding
What are beta blockers used post myocardial infarction for?
Treatment in the acute myocardial infarction
Secondary prevention in the survivors of an acute myocardial infarction
How do beta blockers work?
Competatively inhibit the myocardial effects of circulating catecholamines and reduce myocardial oxygen consumption by lowering heart rate, blood pressure and myocardial contractility
What is an important drug to be given post myocardial infarction?
Beta blockers to reduce mortality and second myocardial infarction
