Venous Disease Flashcards
vein structure?
adventitia media intima intima lined with endothelial cells layer of smooth muscle cells (thinner than in arteries)
are veins pulsatile?
no
vein physiology?
thin walled
non pulsatile
elastic and collapsable
carries 65% of circulating volume
venous flow = cardiac output, how is this?
cardiac output depends on venous return to the heart so venous flow = cardiac output
do veins have tone?
yes
some but not loads or as much as arteries
valves more responsible for preventing backflow
what is vis-a-front?
suction effect of diastole in the heart and low CVP creating a pressure gradient
pulls blood forward in veins
what is vis-a-tergo?
pressure from behind pushing blood through veins
pressure gradient between capillary pressure (20-25) and venous pressure (0)
what else encourages venous flow?
muscle pump in lower limb
thoracic pump (intra-abdominal pressure decreases in expiration which increases flow)
5% also drains via lymphatics
common venous problems?
varicose veins
venous ulcers
DVT
chronic venous insufficiency
what are varicose veins?
dilated, tortuous, superficial veins
can expand to 3-4mm (defined as dilated)
types of varicose veins?
idiopathic
obstructive (DVT, pregnancy, pelvic mass)
congenital (klippel trenauney syndrome)
venous drainage in legs?
blood drains from foot into deep veins at saphenofemoral junction and saphenopopiliteal junction
what is klippel trenauney syndrome?
rare congenital disorder characterised by a triad of cutaneous capillary malformation (port wine stain), lymphatic anomalies and abnormal veins in association with variable overgrowth of bone and soft tissues
investuigation of varicose veins?
doppler (look for venous insuficiency, reflux(blood backflow))
conservative management of varicose?
compression lifestyle (elevate legs, don't stand for too long etc)
interventional management of varicose?
endovenous ablation
foam sclerotherapy
phlebectomy
open
what is chronic venous insufficiency?
funcitonal changes in lower extremity due to persistent elevation of venous pressure
symptoms of chronic venous insufficiency?
pressure feeling aching pain itch bleeding cosmetic disturbance
signs of chronic venous insufficiency?
pitting oedema venous eczema lipodermatosclerosis haemosiderin deposition (breakdown of haemoglobin causing brown staining) venous ulceration
features of a venous ulcer?
in gaiter region (medial leg around medial malleolus)
usually shallow
sloping edges
irregular
arterial ulcers?
bottom of foot
punched out
very painful
management of venous ulcers?
compression (bandages etc to keep venous system intact)
manage infection, diabetes if present and eczema which is often present too
virchows triad?
3 things causing DVT
- stasis of blood flow
- endothelial injury
- hypercoagulability (oral contraceptive, malignancy, thrombophilia etc)
risk factors for DVT?
major surgery (lower limb and pelvic esp) major trauma immobility dehydration OCP coagulopathy malignancy pregnancy
complications of DVT?
PE +/- sudden death recurrence post-thrombotic syndrome ischaemia pulmonary hypertension budd-chiari syndrome (Hepatic venous outflow obstruction)
what is post thrombotic syndrome?
end stage of chronic venous insufficiency
valvular incompetence, venous hypertension, ulceration)
what is wells score?
scoring to assess probability of DVT
2+ points = DVT is likely
how is DVT investigated?
D dimer
then do doppler to confirm DVT if D dimer +ve, contrast venography (technically gold standard but V invasive)
thrombophilia screen
what is D dimer +ve but doppler -ve
stop anticoagulation
bring back in 2 weeks and do another doppler as you need 2 consecutive -ve dopplers to rule out DVT
conservative management of DVT?
exercise, compression
medical management of DVT?
current guidelines = rivaroxaban 15mg BD for 3 months then 20mg OD (duration depends on whether provoked or unprovoked)
DVT prophylaxis?
IVC filter can be used to prevent PE from DVT in high risk (pregnant women etc)
fragmin??, LMWH 2500/5000 units and TED stockings in high risk
who should get prophylaxis?
older, frail, immobile, background of malignancy
components of Wells score?
active cancer
paralysis/recent immobilization of the legs
recently bedridden or surgery in past 12 weeks
localized tenderness along venous area
entire leg swollen
calf swelling >3cm compared to normal
pitting oedema
collateral superficial veins (non varicose)
previously documented DVT
