Lesson 3: Aterial Insufficiency Flashcards
Tunica Externa (Adventitia)
Provides support to vessel walls
Protective outer layer
What makes up tunica externa?
Connective tissue, collagen, and elastin
Tunica Media
Middle layer
Modulates vessel diameter
What makes up tunica media?
Smooth muscle, collagen, and elastin
Intimal Layer
In direct contact with blood
Fragile, easily traumatized
What makes up intimal layer?
Single layer of endothelial cells
Arteries
distribute blood, musculature promotes flow
Arterioles
sympathetic vasoconstriction
Capillaries
single layer of endothelial cells
1 mm long, 8–10μm wide
Most tissues only 0.1 mm from nearest capillary
Basement membrane
Pressure in larger arteries?
90–100 mm Hg in the larger vessels
Pressure in capillaries?
25–35 mm Hg
Pressure as blood returns to right atrium?
0mmHg
How do oxygen and nutrients get to tissues?
Oxygen and nutrients flow via capillaries from the blood into the tissues
What are arterial ulcers caused by?
decrease in arterial blood supply
What are some causes of arterial insufficiency?
Trauma Acute embolism Diabetes mellitus Rheumatoid arthritis Thromboangiitis (Buerger’s disease) Arteriosclerosis
How many Americans affected by arterial insufficiency?
8-12 million
Arteriosclerosis
thickening/hardening of arterial walls
Atherosclerosis
systemic, degenerative process; arterial lumen is gradually and progressively encroached upon by build up of plaque
What layer does Lipids, calcium deposits, and scar tissue accumulate?
intimal layer, causing progressive stenosis
Intermittent Claudication
Activity-specific discomfort due to local ischemia
50% stenosis to have claudication
Pain of intermittent claudication:
Pain stops within 1–5 minutes of ceasing the provocative activity
Pain is described as cramping, burning, or fatigue
Pain location is usually distal to the site of occlusion
Ischemic Rest Pain
Burning pain
~70% stenosis to have ischemic rest pain
Arterial insufficiency (ischemic) ulcers more likely
What is ischemic rest pain exacerbated by?
Exacerbated with elevation and relieved by dependency
Progression of atherosclerotic pain:
arterial insufficieny-intermittent claudication-ischemic rest pain-ulcer
Arterial Ulceration
Result of complete or partial arterial blockage limiting perfusion causing tissue necrosis/ ulceration.
Most common places for arterial wounds:
Wounds between toes, on tips of toes, dorsal aspect of foot, over phalangeal heads, adjacent to lateral malleolous/ tibia or where subject to trauma , such as shin, distal calf
What arterial wounds look like:
Dry wounds with black/gray necrotic tissue & erythematous halo
Thin dry skin, absence of hair, shiny, smooth, cool
Borders of arterial wounds:
Well defined borders “punched out” smooth edges
Symptoms of arterial wounds:
Painful
Dry gangrene
Elevational pallor, dependent rubor
Pain with arterial wounds:
Decreased pain in the dependent position, increased with elevation, exercise (claudication)
Pulses with arterial wound:
Pulses absent or diminished
What does ulceration and gangrene result?
when oxygen requirements of local tissue exceed perfusion
What are arterial insufficiency ulcers most commonly due to
trauma to an ischemic limb
Can be spontaneous
5–10% of all lower extremity ulcers
Associated illnesses with arterial insufficiency ulcers
Coronary disease CHF COPD Hypertension Diabetes mellitus End-stage renal disease Hypercholesterolemia
Risk factors contributing to AI ulcers
hyperlipidemia and elevated LDL Systemic process Smoking Diabetes Hypertension Trauma Advanced Age
Hyperlipidemia and Elevated LDL
Increase cholesterol deposition
Promote plaque growth
Systemic process
Those with CAD at increased risk for PAD
Smoking
Causes vasoconstriction and decreases perfusion
Decreases oxygen availability
Increases clot formation and blood viscosity
Increases cholesterol deposition
Increases mismatch between oxygen delivery and oxygen demand