Flashcards in Venous Insufficiency Ulcers Deck (80)
What percent of the population is diagnose with chronic venous insufficiency, aka post-phlebetic syndrome?
Of the 7 million Americans with venous insufficiency, __% will develop a venous insufficiency ulcer
__-__% of leg ulcers are due to VI
Are men or women more at risk for developing VI ulcers?
women have 3x greater risk
The risk of ulceration is __ times greater in individuals over the age of 65
What is the recurrence rate of venous ulcers?
What is correlated with recurrence?
Pressure within the venous system generaly drops to around __ mm Hg and decreases to almost _ mm Hg by the time it reaches the R atrium
Although the names of the 3 layers of the veins is the same as the arteries there are 3 differences, what are they?
- Smaller amounts of smooth muscle
- Less connective tissue support
At any one time, the venous system stores approximately __-__% of the total blood volume
What are the 3 types of veins?
What are 3 examples of deep veins?
The deep veins carry __-__% of blood back to heart
What are 2 examples of superficial veins?
greater and lesser saphenous
What are the 2 roles of superficial veins?
- Drain skin and subcutaneous tissues
- Assist with temperature regulation
What is the function of the perforating veins?
Connect deep and superficial veins
The proximal flow of venous blood relies on what 3 things?
- Respiratory pump
- Calf muscle pump
It is generally agreed that sustained _____ _______ is required for the development of venous insufficiency ulcerations
What are the 2 most common causes of venous HTN?
- Vein dysfunction
- Calf muscle pump failure
What are the 2 main theories as to the etiology of venous insufficiency ulcers?
- fibrin cuff theory
- WBC trapping theory
According to the fibrin cuff theory vessel HTN and distention cause what?
an increase in vascular permeability
Describe the fibrin cuff theory
Fluid and proteins are allowed to move from within these vessels into the interstitium, the protein fibrinogen is converted to fibrin. Fibrin adheres to capillary walls, forming a "cuff", This cuff is thought to pose a barrier to the exchange of oxygen and nutrients, causing local hypoxia and malnutrition and ultimately cell death and ulceration.
What is hemosiderin staining caused by?
Leakage of red blood cells into the tissue
According to the WBC trapping theory vessel HTN and distention cause what?
Describe the WBC trapping theory
WBCs trap and plug capillaries leading to tissue ischemia. The WBCs move into the interstitium and release proteolytic enzymes and inflammatory mediators causing tissue damage.
What are the 6 risk factors contributing to VI ulcers?
- Vein Dysfunction
- Calf Muscle Pump Failure
- Previous VI Ulcer
- Advanced Age
- Diabetes Mellitus
What is the main cause for venous HTN?
What are 5 means of valvular damage?
- Clot sequelae
Describe why retrograde flow exacerbates venous HTN
The valves may close completely but fail to prevent retrograde flow due to venous distention. Distended veins have an increased vessel diameter allowing some blood to flow backward through the closed, but not overlapping, valve leaflets