mech of acute coronary syndrome

[MudPhud20XX]

So both Non STEMI and STEMI is due to complete occlusion of the artery, correct? Or is this not the case in Non STEMI?

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[chillaxbro]

STEMI is when occlusion is 100% and causes transmural infarction
NSTEMI is when occlusion is less than 100% (like 80%) and causes subendocardial infarction (not as bad)

Edit:
Also, in my mind STEMI = MI and NSTEMI = stable angina pectoris but I'm not sure how accurate that is. Like can you have 90% occlusion and call it an MI? not sure

 

[MudPhud20XX]

Yeah agree, you could also get subendocardial infract from shock I guess. I wasn't sure if stable angina is considered as acute coronary syndrome. Does anyone have a better idea?

 

[walakin25]

Yeah agree, you could also get subendocardial infract from shock I guess. I wasn't sure if stable angina is considered as acute coronary syndrome. Does anyone have a better idea?

ACS is an umbrella term. It includes STEMI, NSTEMI and unstable angina. How do we differentiate b/w STEMI and NSTEMI? EKG. How do we differentiate b/w NSTEMI and unstable angina? Cardiac enzymes. Preach mo fo's.

 

[zhopv10]

^yup, you treat STEMI and NSTEMI virtually the same but you have more time with NSTEMI (STEMI if you are more than 90min from a Cath lab you do the thrombolytics whereas with NSTEMI you have more than 90 minutes probably but ideally you are cathing them as well.). As walakin said for unstable vs NSTEMI you can use cardiac enzymes (also shows you have more time for NSTEMI since cardiac enzymes take a little while to get back).


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[DrPicard]

Theres stable angina, and then there's unstable angina + NSTEMI + STEMI which are collectively referred to as Acute coronary syndrome, since when a patient first presents to you in the ER, you can't distinguish between the three.

NSTEMI and STEMI are both MIs, since myocardial cells die in each of them.

An EKG will either diagnose or exclude STEMI.

If excluded, the distinction between NSTEMI and unstable angina is made with the help of cardiac enzymes (positive only in NSTEMI).

Pathogenesis for stable angina is fixed obstruction that produces ischemia due to an imbalance between supply and demand.

For ACS, its rupture of a plaque with subsequent thrombus formation. Depending on how big a thrombus is formed and how great an obstruction it creates, you can end up with UA, NSTEMI, or STEMI. Since clots can grow over time, its easy to see why UA can progress into NSTEMI and NSTEMI into a STEMI. Hence the time dependent mortality benefit of aspirin and heparin. Not only can these drugs save lives, but the earlier you give them, the greater the morbidity/mortality reduction.

 

[worldbeater]

STEMI is when occlusion is 100% and causes transmural infarction
NSTEMI is when occlusion is less than 100% (like 80%) and causes subendocardial infarction (not as bad)

Edit:
Also, in my mind STEMI = MI and NSTEMI = stable angina pectoris but I'm not sure how accurate that is. Like can you have 90% occlusion and call it an MI? not sure

The cutoff is actually 70% stenosis, but World presents the closest option at 80%. If a patient can exercise and has chest pain when doing so, it's probably less than 70%, if they have pain at rest, it's great than 70% stenosis. Rough way to figure it out from the history of a patient without using any tests. Also if a patient presents with claudication when at walking and at rest (like a mailman or somebody who walks a lot), it is also 70% stenosis and they just give it another name, called Leriche syndrome (named after the dude who discovered it).