lower extremity venous disease and risk factors Flashcards
Virchow’s triad
stasis
intimal injury
hypercoagulability
risk factors for thrombosis
Stasis: bed ridden (paralysis, surgery), elderly, obese, heart disease (CHF, MI, hypotension, COPD)
Trauma: surgery, fractures, needle stick
Hypercoagulability: pregnancy, oral contraceptives (or estrogen intake), malignancy, myeloproliferative disorders, h/o DVT
Ask about grafts, bypass surgery, anticoagulant or lytic therapy
types of venous disease
thrombosis and valve incompetence
types of thrombosis
Acute
Chronic
Phlegmasia alba dolens
Phlegmasia cerulea dolens
Superficial thrombosis
what types of valve incompetence are there?
Chronic
Varicose Veins: Primary, Secondary
when does thrombosis generally occur?
ofter w/ secondary inflammation (thrombophlebitis) and when mechanisms of virchow’s triad are present
signs and symptoms of acute disease
how reliable are clinical symptoms?
what do they entail?
less than 50% reliable
constant acute pain, increased with dependence relieved with elevation
Edema Erythema
respiratory distress (if emboli)
warm leg red streaks
Homan’s sign (pain with dorsiflexion)
Shortness of breath from pulmonary embolism
pulmonary embolism
Emboli from DVT travels to right atrium > right ventricle > pulmonary artery > lungs
Should not get to left side of heart or systemic arterial circulation unless ASD
what is the greatest acute, life threatening risk factor of DVT?
pulmonary embolism
other causes for symptoms (acute disease) aside from pulmonary embolism…
Cellulitis
CHF
Baker’s cyst
Pop aneurysm
lymphadenopathy/ lymphangitis (lymphedema)
musculoskeletal injury
extrinsic compression
chronic disease signs and symptoms
Pain
Chronic limb swelling (esp. ankle)
Hyperpigmentation
Venous ulcerations (can be treated w/ maggot therapy)
what do this images show sequentially?
progression of venous disease
phlegmasia alba dolens spectrum
what does this disease threaten?
what are its symptoms
Phlegmasia – heat; inflamation
Alba – white
Phlegmasia alba dolens (white leg, milk leg)
Limb threatening condition
Acute iliofemoral thrombosis
Distal arterial spasms with decreased pulses
Symptoms
Pallor, Swelling, usually without redness, Cool to touch, May follow parturition or acute febrile illness.
phlegmasia cerulea dolens spectrum
Phlegmasia – heat; inflamation
Cerulea – blue (se –roo’le-a)
Phlegmasia cerulea dolens –blue phlebitis, blue leg
Limb threateing condition from severe extensive acute iliofemoral thrombosis
Results from severely reduced venous outflow, causing decreased arterial inflow
Acute fulminaing form of DVT
Symptoms: Cyanosis (bluish), Sudden pain, Massive edema, Venous gangrene (Cruveilhier), progression PCD to tissue necrosis
how is superficial vein thrombosis diagnosed?
what is it characterized by?
clinically
warmth/local erythema
Localized thenderness
Palpable subcutaneous hard “cord”
what is valvular incompetence?
what type of venous insufficiency does it represent?
What does it cause?
dysfuncitoning venous valves allowing reflux
chronic venous insufficiency
Varicose Veins:
Primary - insufficiency of superficial system only
No obvious cause of valve dysfunction
heredity, trauma, inflammation
Secondary - insufficiency of deep with secondary superficial disease.
AKA postthrombotic syndrome
previous DVT
what does chronic venous insufficiiency affect?
what happens to folks w/ this?
More severe and effecting the deep venous system
Damaged or absent valves allow retrograde flow leading to venous hypertension
Calf muscle pump no longer workds
Often secondary to previous DVT that damage the valves (postthrombotic syndrome)
Progression to: Pitting edema or Ulcerations
where do symptoms of chronic venous insufficiency usually appear?
what do they cause?
Symptoms usually on medial calf and ankle, less commonly lateral side (“Gator zone”)
Hyperpigmentation – “brawny discoloration”
Stasis dermatitis
Edema
Progression to: Pitting edema and Ulcerations
what does this look like?
postthrombotic syndrome
What zone are venous ulcerations generally in?
the “gator zone”
Brown or deep red
Shallow but wide
Irregular boarders
venous ulceration etiology (theory)
- Chronic increase in intraluminal pressure.
- Increased vein wall permeability, plasma and fibrinogen leak out into surrounding tissue.
- Fibrinogen converts to fibrin.
- Barrier formation between capillaries and tissue,
results in a decrease of O2 and nutrient delivery. - Subcutaneous bacteria invasion
what is ambulatory venous hypertension?
what does the insufficiency result in?
What does it do to the calf pressure?
what does it cause?
Increase in venous pressure when person walks or stands
Insufficiency results in early refilling of venous pool after muscle contraction
Causes progressive and sustained increase in calf vein pressure
Causing: Edema, Varicosities or Ulcers
What is the difference between primary and secondary varicose veins?
Primary: Superficial system only, unrelated to deep system
Caused by: Hereditary
Congenital absence of valves
Venous hypertension
Trauma
Inflammation
Secondary: Valve damage from previous DVT
Can result in incompetency of: Perforating veins, Superficial veins, Deep veins, Combination of all
what could these be?
posterior calf varicosities
what types of diagnostic testing are available?
Venography (angiography)
Isotope venography (Nuclear medicine)
Lung perfusion (nuclear medicine)
CT
MRI
Duplex
Plethysmography
d-Dimer assay
venography (angiography) & its limitations
Once considered “gold standard”, not currently used
Limitations: Invasive, Venous assess may be difficult, Inadequate contrast filling
what type of test is this? what does it look for?
Venograms
Intraluminal thrombus, arrows
Calf collaterals
May Thurner’s Syndrom
Compression of left CIV by right CIA
what type of test is a Nuc Med study demonstrates peripheral and pulmonary veins. Very sensitive to actively developing thrombus and calf thrombus.
what are it’s limitations?
isotope venography
Limitations: cannot detect established thrombus
sensitive to clinically insignificant thrombus
24 hours to do test
what test detects pulmonary perfusion defects m/l from emboli? what are its limitations?
lung perfusion scan (VQ scan)
many conditions can cause pulmonary emboli
not specific to venous thrombus
what does nuclear medicine look for?
evluation for PE, secondary to DVT
what type of test shows cross section from pelvis into LE and can reconstruct images?
what are this tests’ limitations?
CT or MRI w/ contrast
requires injections, more costly
What type of noninvasive tests are available for venous insufficiency.
Duplex: 2D, Color Doppler, Spectral Pulsed wave Doppler
Plethysmography: PPG, strain- gauge
what type of blood (laboratory) tests are out there
d-Dimer
Prothrombin Time (PT)
Partial Thromboplastin time (PTT)
International Normalized Ratio (INR)
Platelet count
Fibrinogen
what does the d-Dimer assay test for?
What is elevated d-Dimer test mean?
what other reasons would u see an elevated d-Dimer?
r/o active blood clot formation (Fragment D-dimer; Fibrin degradation fragment)
Normal d-Dimer r/o possibility of active thrombotic formation
Elevated d-Dimer abnormally high level of fibrin degradation products present BUT does not mean a blood clot is present JUST indicates that additional testing may be needed to look for a clot
Other reasons for elevated d-Dimer: recent surgery, trauma, infection, liver disease, pregnancy, eclampsia, heart disease, and some cancers
what blood tests evaluate:
the ability of blood to clot properly
the function of all coagulation factors, used to screen patients for any previously undetected bleeding problems prior to surgical procedures and monitor patients on anti-coagulant drugs (i.e. warfarin (Coumadin) and heparin)
What does a decrease in these times indicates
PT (prothrombin time) and PTT (partial thromboplastin time)
increased risk for clotting
what is the international normalized ratio (INR)?
How has the World Health Organization addressed this system variability problem?
Calculate ratio used to standardize reporting of patient blood clotting properties
INR = (patient PT/mean normal PT)ISI
Normal INR is 2-3
Prothrombin Time (PT) is known to be very system-dependent
- establishment of primary and secondary international reference preparations
- development of a statistical model for the calibration of thromboplastins to derive the International Sensitivity Index (ISI) and the INR.
what can platelet tests tell you?
platelet perform clotting functions
determination of the number of platelets present and/or their ability to function correctly
what do fibrinogen tests tell you?
Fibrinogen is usually ordered with other blood clotting tests to evaluate ability to form a blood clot.
what are ICD9 codes for venous exam?
Patient’s must have one of these symptoms or diagnosis to request the exam.
Exams performed without appropriate codes are subject to denial of payment by insurers.
Note the symptoms listed and think about the connection between these symptoms and LE venous disease.
Also note, an arterial and venous exam can not be ordered for the same day – these will not be reimbursed.
when would a sonographic test of the LE venous system be ordered?
in cases of acute or chronic deep vein thrombosis
what type of medical therapy is availabe for thrombus?
Controlling risk factors – limit bedrest, elastic stockings, elevation , pneumatic calf compression, Unna Boot for ulcers (medicated compression dressing
Anticoagulant therapy for prophylaxis – low dose heparin
Anticoagulant therapy for acute DVT or PE – loading dose of heparin to prevent propagation of thrombus (will not lyse the clot), oral anticoagulation (coumadin). PT and PTT monitored, regulated at 1.5-2 times normal. Treatment for 5-10 days. Patient remains on coumadin for 3-6 months.
what type of surgery thrombosis is available for thrombus?
IVC filter (Greenfield or bird’s nest) with acute DVT in patients where anticoagulant therapy is contraindicated. Done via flouro
External IVC clip can be placed during surgical procedures
Thrombolytic therapy – streptokinase or urokinase to dissolve clot
Thrombectomy in cases of complete obstruction and possible limb loss from phlegmasia cerulea dolens (blue phlebitis), fulminating form of DVT with arterial spasm, pronounced edema, severe cyanosis, purpuric areas and petechiae
what type of therapy is available for varicose veins?
Valvular reconstruction or transplantation for chronic insufficiency – uncommonly done
Ligation of incompetent superficial veins
Vein stripping or excision for varicosities
Percutaneous interventional therapy for varicosities
Sclerotherapy on small varicosities (sodium tetradecyl sulfate)
what is the goal of an endovenous occlusion?
how is this accomplished?
to permanantly collapse the vein.
Accomplished via catheter placement, entering at approximately the knee and advanced to 1-2 cm below SFV.
Occlude the vein from proximal to distal.
Ultrasound required for pre-procedure evaluation, guidance during the procedure and post-procedure evaluation.
what is this procedure?
venous ablation technique w/ ultrasound guidance.
2 - diagram of the radio freqency venous ablation
what type of procedur sends out radiofrequency, a form of electrical energy, to heat the vessel wall causing collagen contraction.
how do they acheive maximum heat?
what is used to stop clot formation?
endovenous radiofrequency closure device
Must have physical contact with the wall, so the catheter has flexible, expandable electrodes.
For maximum heating, blood flow must be stopped during the procedure. Compression at SFJ accomplishes this goal.
Heparinized saline is infused to stop clot formation on the electrodes.
what procedure is being done here?
US guidance and ablation
