Coronary artery disease and acute coronary syndromes

coronary artery disease(CAD)

progressive coronary artery atherosclerosis leading to narrowed or blocked arteries leading to decreased blood flow to the myocardium and ischemia or infarct

most common kind of cardiovascular disease

atherosclerosis patho

chronic endothelial injury(HTN, smoking), fatty streak where lipids accumulate into smooth muscle cells, fibrous plaque where collagen covers the fatty streak, complicated lesion when the plaque bursts and thrombus forms

collateral circulation

growth of new blood vessels(angiogenesis) around a blockage, growth depends on slow chronic ischemia and an inherited predisposition to develop new vessels

CAD risk factors

age and gender, family hx, smoking, DM, HTN, high cholesterol

SADCHF risk factors

smoking, age, diabetes, cholesterol, HTN, family hx

chronic stable angina patho

fixed atherosclerotic plaque roughly 70% stenosed, temporary imbalance between the coronary arteries ability to supply O2 and the cardiac muscles demand for O2, temporary myocardial ischemia leading to angina

acute coronary syndrome(ACS)

atherosclerotic plaque ruptures, thrombogenic surface exposed, platelets clump and form thrombus leading to occluded vessel

rarely but can be caused by coronary spasm

unstable angina

partial occlusion(80%), myocardial cell ischemia

myocardial infarction(NSTEMI)

partial occlusion(80%) just for longer, myocardial cell death in 12 hrs

myocardial infarction(STEMI)

100% occlusion, myocardial cell death in 4 hrs

CAD progression

coronary artery disease - chronic stable angina/acute coronary syndrome - unstable angina/NSTEMI/STEMI

stable angina

predictable- same precipitating even, pattern, quality, severity and timing, anything that increases myocardial O2 demand and/or decreases O2 supply leading to temporary angina

pain stops in less than 10 minutes with rest

angina temporary increase in demand

increase in O2 demand, physical/sexual activity, stress/strong emotions

angina temporary decreased supply

decreased O2 supply, large meal that diverts O2 to the stomach, extreme cold or smoking that causes vasoconstriction

unstable angina

unpredictable, new chest pain, chest pain that is more severe/longer than usual(more than 10 minutes), chest pain at rest

MI clinical manifestations

increased HR and BP following decreased HR and BP from decreased CO(later stage), peripheral artery vasoconstriction, SOB, diaphoresis, anxiety

assessing angina

P: precipitating event

Q: quality(crushing, pressure and no change in pain with breathing or position)

R: region(substernal chest, radiating to shoulder/left arm/jaw)

S: severity

T: timing

MI complications

arrythmias in 80-90%

HR - cell/muscle death - decreased contractility- decreased cardiac output - hypotension - cardiogenic shock(kidney failure), pulmonary edema and hypoxia, pericarditis

NSTEMI

ST depression or T-wave inversion = myocardial ischemia

STEMI

ST elevation = myocardial infarction, resolves in weeks

cardiac biomarkers

troponin, trended Q6hrs x 3 0.04 increase is positive troponin

CK-MB

myoglobin

normal in NSTEMI and unstable angina, elevated in STEMI

coronary artery disease tx

antiplatelet therapy, quit smoking, control DM, BP control, decrease lipid levels, increase fiber, moderate exercise 30 min a day

stable angina tx

stop precipitating factor, rest to decrease O2 demand and use nitro to vasodilate and increase O2 supply

may need interventional coronary angiogram(PCI/stent) or CABG

fast acting nitro

vasodilates and increase O2, take before activity that you know will cause angina or immediately when feeling angina, Q5 minutes up to 3 times, pt should sit or lay down when taking due to drop in BP

stent drug therapy

dual antiplatelet therapy, aspirin indefinitely and another platelet minimum 1 year(clopidogrel/Plavix)

surgical coronary revascularization

coronary artery bypass graft(CABG) indication, failed stent, blockage long and difficult to access, left main CAD or 3 vessel disease, EF less than 35%

unstable angina tx

M: morphine

O: oxygen

N: nitro

A: aspirin

B: beta blocker

post ACS drug therapy

antidysrhythmic(amiodarone, verapamil, diltiazem) statin(atorvastatin) dual antiplatelet therapy for min 12 months, beta blockers(calcium channel blockers if beta blockers are contraindicated) ACE inhibitor