[21] Myocardial Infarction Part 2 Flashcards
my internet is slow so easier to do it on the normal editor, if you start this deck just ask me to merge them first cus i will do eventualy and otherwise you’ll loose your mastery
ok
What is meant by primary PCI?
It is the term used for the emergency treatment of a STEMI, where coronary angioplasty is performed in order to widen the coronary artery
Why is primary PCI practically challenging?
Because it is a potentially complex procedure that requires specialist staff and equipment that not all hospitals have
What needs to be done first to assess suitability for PCI?
Coronary angiography
How is coronary angioplasty performed?
A balloon catheter is inserted into a large artery in the groin or arm, and passed up to the heart using X-ray guidance. Once the narrowed section of coronary artery is reached, the balloon is inflated to widen it, and a stent is inserted into the artery to maintain patency
How can acute thromboembolic disease be treated in selected patients?
With administration of agents that activate the conversion of plasminogen to plasmin
What is plasmin?
A serine protease that hydrolyses fibrin, and therefore dissolves clots
Give three examples of fibrinolytics
Streptokinase
Alteplase
Reteplase
Which fibrinolytic is most likely to cause bleeding problems?
Streptokinase
Why is streptokinase likely to cause bleeding problems?
It causes a systemic fibrinolytic state which can cause bleeding problems, whereas alteplase acts more locally on the thrombotic fibrin to produce fibrinolysis
What is the problem with fibrinolytic therapy in STEMI?
It is unsuccessful in about 20% of infarcted arteries, about about 15% of arteries that are opened will close again
What is the result of fibrinolytic therapy being a bit rubbish?
In an MI, they are reserved for use when angioplasty is not an option
What can be given if patients are at increased risk of recurrent heart attacks?
They can also be given glycoprotein IIb/IIIa inhibitors
What do glycoprotein IIb/IIIa inhibitors do?
They don’t break up clots, but prevent clots from getting bigger, so stop worsening of symptoms
Why is alteplase said to be fibrin selective?
It has a low affinity for free plasminogen in the plasma, but it rapidly inactivates plasminogen that is bound to fibrin in a thrombus or haemostatic plug
Why is streptokinase not fibrin selective?
Because it acts on free plasminogen and induces a general fibrinolytic state
How does reteplase compare to alteplase?
It is similar to alteplase, but has a different half life and a lower affinity for fibrin binding, improving its ability to penetrate into clots
What is the major side effect of fibrinolytics?
Haemorrhage
What can haemorrhage in fibrinolytics?
Previously clinically silent lesions, e.g. peptic ulcer
What are the contraindications to fibrinolytics?
Pregnancy Healing wounds History of cerebrovascular accident Brain tumour Head trauma Intracranial bleeding Metastatic cancer
What is the most reliable method of administration of fibrinolytics for myocardial infarction?
Intracoronary delivery
What is the problem with intracoronary delivery of fibrinolytics in MI?
Cardiac catheterisation may not be possible in the 2-6 hour ‘therapeutic window’
How are fibrinolytics usually administered in MI?
IV
What is the advantage of IV administration of fibrinolytics in MI?
Rapid
Inexpensive
Does not carry risks of catheterisation
