Acute Coronary Sydrome Flashcards
Acute Coronary Syndrome definition
-any array of clinical symptoms resulting from underlying acute myocardial aschemia -almost always associated w/atherosclerotic plaque w/ or isolated from occlusive thrombus
Causes of ACS (10)
- Atherosclerotic plaque rupture with thrombus 2. Atherosclerotic plaque rupture with thrombus 3. Atherosclerotic plaque rupture with thrombus 4. Coronary embolism 5. Congenital anomalies 6. Coronary trauma or aneurysm 7. Severe coronary artery spasm (e.g. cocaine) 8. Increased blood viscosity 9. Spontaneous coronary dissection 10. Markedly increased myocardial 02 demand
Epidemiology of heart disease
-1.7 million/year suffer
Pathophysiology of ACS
⇒ Inflammation + risk factors promote atherosclerosis ⇒ Atherosclerosis promotes a dysfunctional endothelium Dysfunctional endothelium has decreased vasodilator effect and decreased antithrombotic effect compared to normal endothelium ⇒ Inflammatory mediators weaken the atherosclerotic fibrous cap; if cap bursts, thrombogenic tissue factor is released, activating the coagulation cascade and creating platelet aggregation ⇒ Dysfunctional endothelium + coagulation + platelet aggregation = Coronary thrombosis!
Risk factors for atherosclerosis
-Primary risk factors include: Diabetes, hypertension, hyperlipidemia, tobacco -Other possible risk factors: poor diet, inactivity, obesity, kidney disease, family history
Process of plaque rupture
- en
partial artery occlusion
-decreased blood flow in artery distal to partial occlusion –> decrease O2 to myocardium/ischemia
complete occlusions
cessation of blood flow and O2 to the entire portion of myocardium supplied by that artery = ischemia
Transmural MI vs. Subendocardial MI
-Transmural ischemia—spans entire thickness of myocardium; most often associated with complete coronary occlusion -Subendocardial ischemia—involves the innermost layers of myocardium; most often due to partial coronary occlusion -if ischemia is prolonged –> myocyte death and tissue necrosis
Factors involved in diagnsosi of ACS
-ECG -biomarkers -clinical symptoms
ECG changes possible in ACS
ECG changes in subendocardial ischemia
-ST vector wards inner layer and away from leads –> -ST depression
ECG changes in transmural ischemia
-ST vectors towards leads –> -ST elevation
ECG changes in MI
-ST elevations = “STEMI” -no ST elevation = “NSTEMI”
Serum markers of MI
-Tropinin I & Troponin T: sensitive and specific for myocardium; rise 3-4 hrs after onset of pain, peak = ___ -Creatine Kinase–MB isoenzyme: not as secific for myocardium as troponin; rises 3-8 hrs after onset of pain; peak = ____
Clinical symptoms of MI
-angina=chest pain/presure/tightness -SOB -sweating -nauseau -weakness
Angina types
-stabel=present when there is increased demand for myocardial O2 in a reproducible fashion -unstable=increase in duration, intensity or frequency, less provocation
ACS summary comparison [table}
Main goals of treatment of ACS
- relief of ischemia: open the artery or prevent further arterial occlusion & reduce myocardial oxygen demand 2. prevent adverse outcomes
Treatment of STEMI
-Artery is occluded→ Open it! - If artery can be opened within 90 minutes, go to cardiac cath lab to open mechanically (cardiac catheterization). - If cannot be opened within 90 minutes, consider fibrinolytics -If hemodynamically stable, consider oral beta blockers or nitrates to decrease myocardial oxygen demand
Treatment of NSTEMI/unstable Angina
-Artery is partially occluded→halt the thrombotic process from completely occluding the artery by giving anticoagulant and antiplatelet agents -If hemodynamically stable, consider oral beta blockers or nitrates to decrease myocardial oxygen
Anticoagulants/antiplatelets used in NSTEMI/unstable angina
-Anticoagulants: unfractionated heparin, low-molecular weight heparin, fondaparinux (use one -Antiplatelets: P2Y12 inhibitors (clopidogrel, prasugrel, ticagrelor), GIIb/IIIa inhibitors -PLUS Aspirin
Common conditions included in ACS
-unstable angina -NSTEMI -STEMI -most often cause by plaque rupture and thrombosis
Biomarkers in ACS: initial elevation of biomarkers, time to peak elevation, time to return to normal
