ICL 4.4: Clinical Acute Coronary Syndromes Flashcards
what are the 3 main acute coronary syndromes?
- STEMI
- non-ST-segment elevation MI
- unstable angina
what is the pathophysiology of ACS?
vulnerable vessel with atherosclerotic plaque –> acute plaque rupture or erosion –> plaque is exposed to the blood stream which creates thrombosis –> thrombosis then blocks the lumen of the vessel
what is stable plaque?
atherosclerotic plaque with a fibrous cap = layer of tissue between the lipid core and lumen
what is an unstable plaque?
very large lipid core with a thin fibrous cap that often ruptures
when the cap ruptures, the contents of the lipid core are exposed to the blood stream which activates the coagulation cascade and leads to the formation of a thrombus
what is an NSTEMI?
- chest pain or other ischemic symptoms
- abnormal EKG changes (ST depressions or T-wave inversions)
- elevated troponin level
what is unstable angina?
- new or worsening chest pain symptoms
- abnormal EKG changes (ST depressions or T-wave inversions)
- troponin negative
when someone comes into the ER with chest pain, how do you differentiate between STEMI, NSTEMI and unstable angina? how would you treat each?
EKG with ST elevation = STEMI –> immediate cardiac cath lab for stents
positive troponin with other EKG changes = NSTEMI –> cardiac cath lab within 48 hours
negative troponin with normal EKG = unstable angina –> stress test or cardiac cath within 48 hours
why is there ST elevation in a STEMI?
with normal perfusion, ST segment is isoelectric compared to the TP interval
a lack of bloodlfow creates a voltage gradient between normal and ischemic tissue which leads to deflection in the normally isoelectric ST segment
ST elevation on an EKG gives you what clinical diagnosis?
total occlusion of a coronary artery
STEMI
ST depression or T-wave inversions on EKG gives you what clinical diagnosis?
partial occlusion of a coronary artery
unstable angina/NSTEMI
what does time is muscle mean?
by 24 hours you have a total infarct of the whole heart
what are biomarkers? give 2 examples and what they entail
a measurable substance in an organism whose presence is indicative of some phenomenon such as disease, infection, or environmental exposure
measure something in the blood -> detect a disease process -> make a clinical intervention
ex. BNP level is elevated -> this confirms the presence of CHF -> treat CHF
ex. D-dimer level is elevated -> this indicates there is a risk of Pulmonary Embolism -> a diagnostic study is performed to confirm or refute the possibility of Pulmonary Embolism -> PE is diagnosed -> PE is treated
what is the key biomarker in ACS?
Troponin is a commonly utilized biomarker and is very useful for determining if a patient is suffering from an acute coronary syndrome (ACS)
troponin is protein that is normally present within cardiomyocytes but NOT in the circulation
cardiomyocyte Cell death (typically from acute coronary syndrome), results in cell necrosis and spilling of troponin into the blood stream –> troponin is measured from a blood sample
what is the troponin time period post-MI?
peaks around 1 day and clears 5-7 days
CKMB has a similar peak but clears a lot earlier; it’s an older biomarker the isn’t used as much
what is the clinic presentation of a STEMI?
- usually severe, crushing chest pain
- diaphoresis
- vomiting
- left arm pain
- jaw pain
- looks sick
- EKG shows ST segment elevation
- can also present with cardiac arrest: typically Vfib cardiac arrest
what is the initial treatment for a STEMI?
- Aspirin 325 mg x 1 STAT in the ambulance
- Heparin 5000 U bolus in the ER
- Activate STEMI team: goal is to fix the occluded artery within 90 minutes
door-to-balloon time <90 minutes because time is muscle!
- Emergency Percutaneous coronary intervention (PCI)
- DAPT: dual antiplatelet therapy after PCI= aspirin plus a P2Y12 antagonist
what is the initial treatment for a NSTEMI?
if patient present with chest pain or SOB with ST depressions and/or t wave inversion and elevated troponin levels:
- admit to hospital
- aspirin and heparin drip
- statin and beta blocker
- nitroglycerin for chest pain relief
- cardiac catheterization within 2-48 hrs as appropriate
- DAPT
what happens on the EKG if you don’t treat a STEMI?
acute: ST elevation
hours: Q wave appears
days 1-2: T wave inversion and Q wave is deeper
days later: ST normalizes, T wave inverted
weeks: ST and T waves are normal