438
U N I T 5
Circulatory Function
Diagnosis and Treatment.
The diagnosis of vari-
cose veins often can be made after physical inspec-
tion. Primary varicose veins should be differentiated
from those secondary to chronic venous insufficiency,
retroperitoneal venous obstruction, or congenital
venous malformations. The Doppler ultrasonic flow
probe also may be used to assess flow in the large ves-
sels. Angiographic studies using a radiopaque contrast
medium also are used to assess venous function.
Treatment measures for varicose veins focus on
improving venous flow and preventing tissue injury.
When correctly fitted, elastic support stockings or
leggings compress the superficial veins and prevent
distention. The most precise control is afforded by
prescription stockings, measured to fit properly. These
stockings should be applied before the standing position
is assumed, when the leg veins are empty. Sclerotherapy,
which often is used in the treatment of small residual
varicosities, involves the injection of a sclerosing agent
into the collapsed superficial veins to produce fibro-
sis of the vessel lumen. Surgical treatment consists of
removing the varicosities and the incompetent perforat-
ing veins, but it is limited to persons with patent deep
venous channels.
Chronic Venous Insufficiency
Chronic venous disease of the lower extremities is mani-
fested by venous hypertension and a range of signs, the
most obvious of which are varicose veins and venous
ulcers due to venous insufficiency.
74,75
Venous hyperten-
sion represents a sustained increase in venous blood
pressures.
Etiology.
Chronic venous insufficiency is most com-
monly caused by reflux through incompetent veins,
but can also be caused by venous outflow obstruction
and impaired function of the skeletal muscle pumps.
Pressure in the veins of the legs is determined by two
components: a
hydrostatic component
related to the
weight of a column of blood below the level of the heart,
and a
hydrodynamic component
related to the action of
the skeletal muscle pump. Prolonged standing increases
venous pressure and causes dilation and stretching of
the vessel wall. When a person is in the erect position,
the full weight of the venous columns of blood is trans-
mitted to the leg veins. The effects of gravity are com-
pounded in persons who stand for long periods without
using their leg muscles to assist in pumping blood back
to the heart.
Clinical Manifestations.
Chronic venous insufficiency
is characterized by signs and symptoms associated with
impaired venous blood flow. In contrast to the ischemia
caused by arterial insufficiency, venous insufficiency
leads to tissue congestion, edema, and eventual impair-
ment of tissue nutrition. The edema is exacerbated by
long periods of standing. Necrosis of subcutaneous fat
deposits occurs, followed by skin atrophy. Brown pig-
mentation of the skin caused by hemosiderin depos-
its resulting from the breakdown of red blood cells is
common. Secondary lymphatic insufficiency occurs,
with progressive sclerosis of the lymph channels in the
face of increased demand for clearance of interstitial
fluid.
In advanced venous insufficiency, impaired tissue
nutrition causes stasis dermatitis and the development
of stasis or venous ulcers
74,76
(Fig. 18-19). Stasis der-
matitis is characterized by the presence of thin, shiny,
bluish brown, irregularly pigmented, desquamative skin
that lacks the support of the underlying subcutaneous
tissues. Minor injury leads to relatively painless ulcer-
ations that are difficult to heal. The lower part of the leg
is particularly prone to development of stasis dermati-
tis and venous ulcers. Most lesions are located medially
over the ankle and lower leg, with the highest frequency
just above the medial malleolus.
Treatment of venous ulcers includes compression
therapy with dressings and inelastic or elastic bandages.
FIGURE 18-19.
Classic appearance of a venous stasis ulcer.
A venous stasis ulcer is usually located above the medial
malleolus and has an indolent appearance with granulation
tissue at the base that does not appear ischemic. Scarring
of variable extent usually surrounds chronic and recurrent
ulcers. Hyperpigmentation, lipodermatosclerosis (induration
involving skin and subcutaneous fat), and stasis dermatitis
are variably present in the lower third of the leg. Pedal pulses
are usually palpable. If they are not palpable because of
induration or swelling, ankle pressures measured by means
of Doppler ultrasonography will be normal in the absence of
associated ischemic disease. (From Raju S, Neglén P. Chronic
venous insufficiency and varicose veins. N Engl J Med.
2009;360(22):2322. Copyright © 2009. Massachusetts Medical
Society.)
