Endothelium, Plaque Rupture, & Vascular Injury Flashcards
Stages of endothelial dysfxn
-fatty streak
-stable plaque (angina)
unstable plaque (acute myocardial event)
Mechanisms of ischemia
- stroke: usually embolic
- CAD
- Renal artery disease
- aneurysm: atherosclerosis –> vessel degradation
- peripheral artery disease
Stroke main mechanism of ischemia
- atheroembolism from carotid bifurcation ( sudden loss of vision = sx if plaques are embolizing
- thromboembolization from left atrial appendage in setting of atrial fibrillation
CAD
thromboembolism
angina mech
-stable, obstructive plaque
MI
- exertional chest discomfort
- ruptured plaque, in-situ thrombosis, not necc. obstructive prior to rupture
- varied severity: non-occlusive thrombosis vs. occlusive thrombus
Tx of MIs of different severity
- non-occlusive can usually be resolved w/anticoag and vasodilators
- occlusive=clinical emergency —> revascularization/stenting
Varying severity of ruptured coronary plaques (diagram)
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Peripheral arterial disase
- caludication
- acute limb ischemia
claudication
- obstructive stable plaque
- ~angina @ periphery –> pain w/exercise due to limited flow
acute limb ischemia
- acute obstruction of blood flow
- atheroembolization (e.g. from aortic aneurysm) or thromboembolization
- rarely in-situ thrombosis
Stable plaques
- less biologically active
- cause angina/claudication (exertional ischemia) of
- less likely to cause thrombotic and embolic events
unstable plaque
- more biologically active
- more likely to embolize/cause thrombosis
Venous thrombosis
-fibrin rich
-RBC
0areas of stasis
-genetic predispostiation
-enviro predisposition
-treated w/antigcoagilation
Arterial thrombosis
- platelet rch
- plaque rupture
- areas of high flow
- atherolsclerosis, traum, APLA
- focus on antiplatet therapy
Vasospastic disorders
- dysfxn endothelium involved but not necessarily thrombosis or atherosclerosis
- **Raynauds (primary and secondary)
Characteristics of dysfxnl endothelium
- inflammation
- thrombosis
- spasm
Endothelium definition
tissue consisting of single layer of cells that lines the blood and lymph vessels, heart, and some other cavities
Normal vs. Activated Endothelial cells
- normal: impermeable to large mlx, anti-inflammatory, resist leukocyte adhesion, promote vasodilation, resist thrombosis
- activated: permeability, inflammatory cytokines, leukocyte adhesion mlx, decreased vasodilatory mlx, decreased antithrombotic mlx
Characteristics of nitric oxid synthase
- Expressed on luminal side of endothelium
- Responds to multiple stimuli
- NO from Arginine
- Multiple cofactors
- NO diffuses to smooth muscle in media
- cGMP-mediated vasodilatation
