Endothelium, Plaque Rupture, Vascular Injury (complete) Flashcards
What are the layers of a blood vessel? Outside to inside
- Adventitia
- External elastic lamina
- Media
- Internal elastic lamina
- Intima
What is in the intima?
- endothelium
- thin layer CT
What is in the media?
- VSM
- CT
What is in the adventitia?
loose CT
Describe the differences between large arteries, smaller arteries, and arterioles (in terms of what it’s made of)
Large: more elastin
Smaller: more collagen
Arterioles: more SM
Describe normal endothelial cells
- impermeable to large molecules
- Anti-inflammatory
- Resist leukocyte adhesion
- Promote vasodilation
- Resist thrombosis
Describe activated endothelial cells
- ^ permeability
- ^ inflammatory cytokines
- ^ leukocyte adhesion molecules
- Decreased vasodilatory molecules
- decreased antithrombotic molecules
Describe smooth muscle cells
- normal contractile function
- maintain ECM
- Contained in medial layer
Describe activated smooth muscle cells
- ^ inflammatory cytokines
- ^ ECM synthesis
- ^ migration/proliferation into subintima
What’s the main thing you need to know about nitric oxide?
it’s a vasodilator!
What happens to NO when you activate an inflammatory state?
it decreases
Describe vulnerable plaques
- Less fibrous tissue
- Less calcified
- More lipid content
- More inflammation
- More apoptosis
Describe stable plaques
- Rich in fibrous tissue
- Calcified
- Less lipid content
- Less inflammation
- Less apoptosis
Describe plaque rupture and how it leads to thrombosis
- “Stable” plaque w/ small lipid pool, thick fibrous cap, preserved lumen
- Becomes vulnerable plaque (large lipid pool, thin fibrous cap, many inflammatory cells)
- Then ruptures w/ thrombus formation
- Can either lead to acute MI
- Or become a healed rupture w/ narrowed lumen and fibrous intima (lots of occlusion)
What are the 3 stages in the development of atherosclerotic plaque?
1) Fatty streak
2) Plaque progression
3) Plaque disruption
Describe the fatty streak as a stage in the development of atherosclerotic plaque
- endothelial dysfunction
- Lipoprotein entry and modification
- Leukocyte recruitment
- Foam cell formation
Describe plaque progression as a stage in the development of atherosclerotic plaque
- SM cell migration
- Altered matrix synthesis & degradation
- It really starts to build up
Describe plaque disruption as a stage in the development of atherosclerotic plaque
- Disrupted plaque integrity
- thrombus formation
This is the thing that can lead to MI
- happens even when there is only a 50% occlusion => if the plaque is vulnerable then it can do anything!
Describe the common mechanism of stroke
- Atheroembolization from carotid bifurcation lesion
- Source lesion does not need to be obstructive (<70% diameter reduction)
- Ophthalmic artery
Also:
- Thromboembolization from left atrial appendage in setting of AFib
Describe the type types of MI
1: plaque ruptuse => non-occlusive thrombosis => some flow but intermittent occlusion/embolization => stabilize w/ anticoag/ vasodilators
2: Plaque rupture => occlusive thrombus => no flow => clinical emergency => recanalize
Describe peripheral arterial disease
Manifestations:
- Claudication: obstructive (>70%) stable plaque
- Acute limb ischemia: acute event obstructs blood flow w/o prior development of collaterals — could be athero- or thromboemboli (rarely in-situ thrombosis)
