CC 6 - Atherosclerosis, Hypertension, and Million Hearts Flashcards
Definition of stenosis?
Luminal narrowing of the artery
What is another word for stenosis?
Lesion
What is a plaque?
Atherosclerotic deposition within the intima or adventitia of vessels
What does PCI stand for? What does it mean?
Percutaneous Coronary Intervention
Interventions to put in balloons and stents inside vessels
What does ACS stand for? Definition?
Acute Coronary Syndrome = any condition brought on by a sudden reduction or blockage of blood flow to the heart
What does STEMI stand for?
ST Elevation Myocardial Infarction
What does NSTEMI stand for?
Non-ST Elevation Myocardial Infarction
Is a lesion always visible on an angiogram?
NOPE, flow does not exclude the possibility of a narrowing present
What are the 3 types of ACS? What do we call type 2 and 3 together?
- STEMI
- NSTEMI
- Unstable angina
2 + 3 = Non-ST Elevation Acute Coronary Syndrome
What does PMH stand for?
Past Medical History
What does NSR stand for?
Normal Sinus Rhythm (on EKG)
At what point does atherosclerosis become symptomatic?
When plaque stenosis exceeds 70% of the vessel lumen
What fraction of all deaths in the US and Europe are due to vascular disease? What are these exactly due to?
Half of all deaths:
- 2/3rds: atherosclerosis and thrombosis of the coronary arteries
- 1/3rd: thrombosis and hemorrhage in other arteries (e.g. stroke)
What is the most common first symptom of coronary artery disease?
Unexpected myocardial infarction OR sudden death (first symptom for 50% of people)
How many people have a myocardial infarction each year?
1,450,000 (1 every 25 seconds)
How many people have a stroke each year?
800,000
What fraction of people die from CVD each year?
1 in 3
What are most acute coronary syndromes caused by?
Rupture of lesions less than 50% stenosed (2/3rds due to this)
Why has CVD incidence fallen over the years?
- Less tobacco
- Better BP control
- Better lipid control
- Other unknown factors
Where does the word atherosclerosis come from?
Greek:
- Athero = gruel or porridge
- Sclerosis = hardening
What is the definition of atherosclerosis?
Progressive pathological condition characterized by the accumulation of lipids, cells, and fibrous elements in the large arteries (but also smaller vessels)
What other diseases does atherosclerosis underlie?
- CAD
- Cerebrovascular disease
- Diseases of the aorta and peripheral arterial circulation
Why is the intima of the arterial wall so important?
If it is damaged it exposes a lot of tissue factors and pro-coagulable factors causing blood clots
Under basal conditions, in what state does the endothelium maintain the vessels?
Relatively dilated state
What happens during an exercise stress test?
During exercise the arteries to the skeletal muscles and to the heart should widen due to shear stress and metabolic regulation, so if someone has atherosclerosis as you increase the blood demand, the fixed stenosis will prevent adequate blood flow causing ischemia which will cause certain EKG patterns or specific results on other imaging tests
List the 5 normal characteristics of endothelial cells?
- Impermeable to large molecules
- Anti-inflammatory
- Resist leukocyte adhesion
- Promote vasodilation
- Resist thrombosis
How does atherosclerosis affect the normal characteristics of endothelial cells?
- Increased permeability
- Increased expression of inflammatory cytokines which allow cells flowing through the vessel to dock on the endothelial cell wall
- Increased leukocyte adhesion molecules, so do not resist their adhesion as well
- Decreases vasodilatory molecules so do not promote vasodilation as well
- Decreased antithrombotic molecules so do not resist thrombosis as well
How does atherosclerosis affect the smooth muscle cells of vessels?
- Increased inflammatory cytokines
- Increased extracellular matrix synthesis
- Increased migration and proliferation into subintima
Which cells of the blood vessels maintain the extracellular matrix?
Smooth muscle cells
Where does a lot of the endothelium dysfunction occur in the CV system with atherosclerosis? Why?
Regions of vessel bifurcation because of turbulent flow
What are 8 interventions that improve endothelium function in atherosclerotic patients?
- Smoking cessation
- HT control
- Cholesterol lowering/statin drugs
- Exercise
- ACE inhibitors
- Estrogen
- Antioxidants
- Reduction of inflammation
What is the earliest abnormality caused by atherosclerosis? Causes?
Damage to the vascular endothelium causing vascular endothelial dysfunction
Causes: smoking, HT, hyperlipidemia, diabetes, obesity, aging, lack of exercise…
Describe the progression of atherosclerosis.
Vascular endothelial dysfuntion => increased expression of adhesion molecules on the endothelial cells + decreased ability to release NO and other substances that prevent adhesion of macromolecules => monocytes and lipids accumulate at the site of injury => monocytes cross endothelium and enter the intima => monocytes differentiate into macrophages => macrophages ingest and oxidize the lipoproteins via scavenger receptors => macrophages have a foam-like appearance = foam cells forming a lipid core => foam cells aggregate on blood vessel and eventually pop leaving cholesterol crystal which cause fatty streaks => with time fatty streaks grow larger and attract macrophages by secreting chemo and cytokines which secrete substances that cause inflammation and cause the fibrous (collagen and elastin) and smooth muscle cells to proliferate to form fibrous plaques aka atheromas => vicious cycle leading to the development of vulnerable or stabilized plaques
What kind of lipids accumulate on a damaged endothelium?
LDLs = low density lipoproteins
When do LDLs get oxidized during atherosclerosis? What does this cause?
When it gets under the subendothelial matrix => macrophages and monocytes recognize them
At what age do macrophages start accumulating in the vessel walls?
Infancy
At what age do fatty streaks appear in the vessel walls?
During early adolescence (as early as 9 yo)
At what age do lesions appear in the vessel walls?
Around 20