1. ACS / CAD Flashcards
What is the pathology behind coronary artery disease?
- There is an increased amount of cholesterol in the blood
- This cholesterol binds to damaged sections of the arterial wall
- White blood cells flood to the area to try and remove the cholesterol, kicking off an inflammatory process known as atherosclerosis
- Over time, this increases in size to a plaque, which eventually bulges into the vessel and obstructs blood flow
What are the non-modifiable risk factors for coronary artery disease?
- increasing age
- male sex
- family history of CAD
- Caucasian ethnicity
What causes stable angina?
Partial occlusion in a coronary artery that allows adequate blood flow to the rest of the heart at rest, but upon exercise or emotion, it does not, so results in ischaemia to part of the heart downstream from the clot
How is the pain in angina described?
Tight / Heavy strangling feeling in the chest, which does not radiate
What is unstable angina
It is the next progression from stable angina. It is a constant heaviness / tightness in the individuals chest, even when at rest
How else can angina be characterised other than stable and unstable?
Typical and atypical
What is the difference between typical angina and atypical angina? What if there is only 1 criteria met?
Typical angina has these 3 characteristics;
- Constricting discomfort in the front of the chest
- Brought on by physical exertion
- Relieved by rest or GTN within about 5 minutes.
If only 2 of these criteria are met, then it is described as atypical angina. If only 1 of the criteria is met, it is said to be non-cardiac chest pain.
What is an NSTEMI?
Non-ST elevation myocardial infarction.
It is the progression from unstable angina.
It is one of the ACS.
It is when the plaque embolises, blocking a smaller artery downstream, causing infarction distally and then ischaemia proximally
It is said to cause a subendocardial infarction
What is a STEMI?
ST elevation myocardial infarction.
It is more severe than a NSTEMI
It is when the plaque builds up and fully excludes the artery, causing widespread infarction distally, which slowly progresses proximally unless the occlusion resolves.
It is said to cause a transmural infarction
What are the 3 conditions that are included as an Acute Coronary Syndrome (ACS)?
- unstable angina
- NSTEMI
- STEMI
From most likely to least likely, in which coronary arteries do plaques commonly occur?
- Left anterior descending
- Right coronary artery
- Left circumflex artery
Are NSTEMIs or STEMIs more common?
NSTEMIs are twice as common as STEMIs
What is the hospital mortality rate of STEMIs and NSTEMIs?
What about after 6 months and beyond?
STEMI - 7% hospital mortality
NSTEMI - 3.5% hospital mortality
However after 6 months, they both have the same mortality rate, and then by 4 years, those who had an NSTEMI are 2x more likely to die
What are the 3 layers of the heart?
Endocardium - layer closest to the heart
Myocardium - muscle layer in the middle
Epicardium - this is otherwise known as the viceral layer of serous pericardium
Distal to this is the pericardial cavity, parietal layer of serous pericardium and then the fibrous later of pericardium
Where does the endocardium receive its blood supply from?
It receives oxygen directly from the blood in the ventricles and atria