Venous Disease Flashcards
How to size iliac vein stents
Proper sizing is needed for iliac venous stenting to avoid the complication of migration. Stent migration to the right heart or the pulmonary artery is potentially lethal and requires advanced endovascular retrieval techniques. If these endovascular techniques are unsuccessful, then open surgery with stent extraction is required. Most key opinion leaders recommend oversizing the venous stent by 10% to 15% of the largest diameter of the normal adjacent vein.
Placement of iliac stents
Prior to the recent introduction of dedicated nitinol venous stents in the United States, the most frequently placed stent for iliac vein compression (thrombotic or nonthrombotic) was a closed cell braided stent. Although this stent has some desirable properties for venous stenting, such as adequate outward radial force, its placement can be imprecise. Precise placement at the iliocaval confluence can lead to distal stent collapse because the ends of the stent have the least outward radial force. It is recommended that this stent be extended into the inferior vena cava for several centimeters. This cranial extension can result in the stent covering or “jailing” the contralateral limb. Several authors have demonstrated an incidence of contralateral deep vein thrombosis of up to 10% when this stent is extended across the contralateral limb, which is significantly higher than in cases where the stent is not extended across the iliac confluence.
Nutcracker syndrome
Nutcracker syndrome is the compression of the left renal vein between the superior mesenteric artery and aorta, or the vertebral spine and aorta if there is a retro-aortic left renal vein. Hematuria can be either microscopic or macroscopic, and is the most common clinical feature of NCS, especially when there is left flank pain. Patients with abdominal pain secondary to NCS have left flank pain rather than right flank pain. Patients can have vulvar varices in addition to gluteal and lower extremity varicosities, but these are also seen with other venous disorders and are only possibly related to NCS. Dysuria and dysmenorrhea can occur with NCS but are less suggestive of the NCS than hematuria.
Indication for anticoagulation in SVT
Anticoagulation for patients with SVT should be considered for those at increased risk for thromboembolism and for those with recurrent superficial vein thrombosis. These include patients with positive medical risk factors for vein thrombosis, an affected vein segment ≥5 cm, and a thrombus in proximity to the deep venous system (≤5 cm). A significant reduction in the incidence of pulmonary embolism has not been consistently demonstrated. The largest placebo-controlled trial, CALISTO trial, randomly assigned 3,002 patients to receive fondaparinux (2.5 mg subcutaneous daily for 45 days) or placebo. Patients had duplex-confirmed thrombophlebitis over more than 5-cm length of vein. Significant reductions were seen in the incidence of thrombus extension (0.3 versus 3.4 percent), recurrence of phlebitis (0.3 versus 1.6 percent), and deep vein thrombosis (0.2 versus 1.2 percent).
Where should filter be placed in pregnancy
suprarenal- due to risk of compression in infra-renal filter by gravid uterus
What are RF for DVT
hospitalizations
recen surgery
trauma
cancer
indwelling catheter
extermity paresis
varicose veins
CHF
increasing age
long-haul travel
thrombophilia
pregnancy
OCP
IBD
antiphospholipid antibodies
iliac vein compression
What % of sympto DVT have PE?
50%
What is post thrombotic syndrome? What is the mechanism? what are RF?
50% of DVT
pain, edema, heaviness, hyperpigmentation, ulceration
this is a consequence of valvular reflux, persistent venous obstruction,
generally thrombus does not adhere to valves secondary to likely endothelial properties. Protective mechanism fails then contribute to post-throbotic syndrome
higher rates of PTS in anticoag alone vs thrombolysis in CaVent study
RF rate of recanalization, anatomic distribution of reflux and obstruction, extent of reflux, recurrence, BMI, influence occurrence of PTS
Chronic venous insuff in DVT/PE 1, 5, 10, 20 year 7%, 15%, 20%, 27%
Incidence of venous ulcers 4%
What are features of DVT on DUS?
Absence of spontaneous flow
Absence of flow augmentation
Visible thrombus
Absence of compressability
Absence respiratory phasicity
How to distinguish DVT acute from chronic?
acute vs chronic
total occlusion vs partial
clot retracted vs adherent
clot compressibility soft vs firm
smooth vs irregular
homo vs hetero
fain echolucent vs echogenic
no collaterals vs present
Pitfalls in DVT identification?
Misidentification of veins
Missing duplicate venous system,
Systemic illness of hypovolumia Obese or edematous images suboptimal
Areas not amnebale to compression
What are means of DVT prophylaxis peri-op?
Hydration and analgesia, early ambulation
Passive exerises in immobile
Leg elevation
Mechanical methods
Graduated stockings,
intermittent pneumatic compression
pressure 35-55 mmHg
pharma
What are CI to use of DVT prophylaxis?
bleeding disorders
hemophilia, thrombocytopenia <70
active/recent bleeding
eso varices
peptic ulcer
INB, GI bleed within 3months
precuation
liver, renal fialure
multiple truama
spinal/optho surgery
How does heparin work?
binds to enzyme inhibitor ATIII causing activation
inactivates thrombin and Xa
What are difference in unfractionated and LMW Heparin (fragmin)?
heparin vs LWMH
>daltons vs HIT 5% vs
How does warfarin work?
What is duration of action?
antagonizes vit K1 recycling, depleting active vit K1.
inhibiting synthesis of vit k dependent clotting factors
X, IX, II, VII (1927)
2-5 days
What is fondaparinox?
factor Xa inhibitor by causing conformational change in AT
no thrombocytopenia
What are examples of direct thrombin inhibitors?
What are they used for?
hirudin, argatrobanm, dabigatran
treatment of HIT
What is rivaroxaban?
direct oral factor Xa inhibitor
What is prophy dose of Uheparin, fragmin?
5000units bid or tid
2500-5000units OD
What are DVT pophy regimen?
ver low risk–agressive and early mobilization
low risk–mechanical prophy (IPC)
mod risk–heparin +/_stokcing/IPC
high risk–high does heparin
stocking/IPC
What are low and high risk procedures for DVT?
lap chole, appendectomy, prostatectomy, inguinal hernia repair, mastectomy
bariatric, cancer, neuro, TKR, THR, fractured hip
What is treatment for DVT?
elevation of leg and ambulation
anticoagulation
warfarin for 3 months or beyond if high risk
prevent recurrence/extension
bleeding risk 1-3%
stockings likely reduced PTS
What are the deep veins of the leg? arm?
iliac, femoral, popliteal, tibial
brachial, axillary, subclavian
What is the rational for surgical thrombus removal?
Rational for thrombus removal
Venous patency restored, valve function maintained, QOL improved, risk of recurrence reduced
Decreased comparment pressure with clot removal
What is the evidence for iliofem thrombectomy?
RCT for ilifem thrombectomy showed better vein patency, lower venous pressure, less edema and less Post thrombotic symptoms (all signif)
Observational study for iliofem, ctheter directed thormbolysis showed improved QOL
RCT for CDT
Improved venous patency and reduction in valvular incompetence
CaVenT trial
Iliofem patency 6 months and PTS 2 years
Alteplase 0.01mg/kg/hr max 96 hours
Less PTS and better iliofem patency
Bleeding complications 3.3%
NNT to prevent one PTS is 7 (but not all patients in trial had iliofem dvt so maybe higher)
How does thrombus form?
Glu-plasminogen binds to fibrin which converts to ley-plasminogen. This produces more binding sites for plasminogen activators and more efficient production of plasmin. Thrombolysis occurs with the activation of fibrin bound plasminogen to plasmin
What is the dose of alteplase for infusion? intraop bolus?
10mg cathflo in 250ml NS
infuse 1mg/hr x 8hours then 0,5mg/hr until repeat angio
max dose 20mg/24hr
max duration 96hours
6-10mg bolus at 1mg/ml
What are benefits of intra-thrombus delivery of alteplase?
Less systemic circulation
Protects plasminogen activators from circulating plasminogen activator inhibitor
Protects the active enzyme plasmin from neutralization by circulating antiplasmin
What is success rate of CDT? complication rate?
80-90%
bleeding 5-10 ICH rare
What are some pharmacomechanical devices for DVT?
Amplatz
Angiojet
Treotola
Oasis
What are principles of surgical thrombectomy 6?
identify cause
define extent
prevent PE
complete thrombectomy
ensure unobstructed inflow and outflow
prevent recurrence
Describe surgical procedure for venous thrombectomy?
For infrainguinal thrombus, elevated and compress the leg with rubber bandage, dorsiflex foot and calf and thigh squeezed
If persists then cutdown on post tib vein and advance fogarty from this direction
Can also use saline to flush from post tib end
Iliofem then performed with 8-10 balloon
Can use ballon occlusion from contralateral limb to prevent distal embolization
create AVF
IVC filter if thrombus in IVC
What are principles of AVF in venous thrombectomy?
Then create a small AVF at amputated end of the proximal saphenous. Limited to 3.5-4 mmm, increased venous velocity but not venous pressure
No increase in pressure should be recorded with open avf, if it does then the AVF is constricted
What are the AHA guidelines for managmeent of DVT?
Low risk of bleeding patient may be selected for CDT or pharmacomechanical CDT as first line treatmenet to prevent PTS
Surgical venous thrombectomy considered if iliofem thrombus (IIb)
How do you define MAssive PE?
Massive PE defined by systemic hypotension (40mmhg, syncope or cardiac arrest.
What are ideal features for IVC filter design? 8
Non thrombogenic material
Self centering
Secure fixation
No impendence to flow
Single trapping level and conical design (highest filtering to flow volume ratio
Retrievable
Visibility on imaging
Cheap
What are evidence-based indications for IVC filter?
VTE CI to anticoag
VTE with complications of anticoag
recurr PE on anticoag
VTE inability to achieve therapeutic anticoag
What are expanded indications for IVC filter?
poor compliance
free-floating ilio-caval
RCC with renal vein extension
VTE with limited CP reserve
VTE in cancer, burn, pregnant patient
cord injury
trauma patients
known hypercoag
What are CI for IVC filter?
chronically occluded cava
vena cava anomalies
inability to access cava
vena cava compression
no location for placement
What are complications of filter placement?
PE
access site thrombosis
filter migration
cava penetration
cava obstruction
filter fracture
guide wire entrapement
What are anomalies of the IVC complicating filter placement?
IVC transposition, duplication, agenesis
What is IVC transposition?
Left sided IVC drains into the left renal vein which crosses to the right and continues in normal direction. Suprarenal filter placement
What is IVC agenesis?
Absence of infraarenal segment
Azygos drainage. Place filter here
What is IVC duplication?
Right sided IVC drains the right iliac vein and right renal vein
The left sided ivc is susally smaller, drains left iliac vein, and joins left renal vein where it crosses over into the right sided vena cava
Place filter in each cava
When and how to place suprerenal filter?
thrombus in IVC, malpositionned in infrarenal, duplicate IVC, ovarian vein thrombosis, pregnancy
plae above highest renal so hooks not in RV
What is superficial thrombophlebitits?
Superficial thrombophlebitis or superficial vein thrombosis with phlebitis is a condition where superficial veins thrombose or clot can cause inflammation and induration (hardening, thickening) of the overlying skin.
Where is STP most common?
SV and tributaries
GSV >SSV
What are RF for STP?
endothelial injury, varicosities (most common), neoplasm, SLE, vasculitis
What organism cause suppurative TP?
s.aureua, pseudomonas, klebsiella, enterococcus, candida
What is incidence of STP after EVLT?
11%
How to diagnose STP?
Pain, erythema, tenderness or induration
DUS
What is tx for STP?
NSAIDS
topical liposomal heparin
What is the benefit of thrombolysis for DVT?
more complete clot resolution
preserved valve function
higher bleeding then heparin alone
How does cancer cause thrombosis at cellular level?
Tumor cells can express TF
TF binds to VII and initiates X and XI leading to thrombin generation
Cancer pro coagulant directly activates X
Contraindications to EVLT
Some authors have expressed concern that veins >12 mm have an increased risk for incomplete obliteration and target vein phlebitis, but several studies have shown that veins >12 mm have similar outcomes with regards to closure rate, complications, and clinical and quality of life improvement.
If the vein is just below the skin and cannot be pushed down with tumescent solution at least 1 cm below the surface, there could be problems with staining and thermal injury to the overlying skin.
If there is tortuosity within the vein, it might limit the ability to pass the catheter.
The duration of reflux in this scenario meets pathologic criteria (great than 0.5 seconds). The presence of acute thrombus within the GSV is a contraindication to endovenous ablation.
Riks of sclerotherapy
Post-sclerotherapy pigmentation results when hemosiderin staining of the dermis. It occurs in 11% to 80% of patients, but persists in only 1% to 2% at 1 year. Hemosiderin is an indigestible component of the hemoglobin degradation and its elimination may take years. Thrombi occur in all veins after sclerotherapy. Incisional draining these foci of blood 2 to 4 weeks after the therapy may help decrease hyperpigmentation. Telangiectatic matting is the new appearance of fine red telangiectasias thought to result as response to the injured vessels. It occurs in 5% to 75% of patients. Most resolve within a year, with less than 1% persisting. Cutaneous necrosis is caused by extravasation of a sclerosing agent, injection into a dermal arteriole, reactive vasospasm, or excessive cutaneous pressure created by compression. This occurs in less than 1% of patients. Deep venous thrombosis has been described after sclerotherapy, but is rare. It is thought to be related to higher doses of sclerosant in one treatment setting. Cutaneous nerve injury has been described but is rare.
Common cause of secondary lyphemdema
filiriasis
Stemmer’s sign
Stemmer’s sign is a thickened skin fold at the base of the second toe or second finger that is a diagnostic sign for lymphedema. Stemmer’s sign is positive when this tissue cannot be lifted but can only be grasped as a lump of tissue. It is negative when it is possible to lift the tissue normally. This is a condition where the skin often cannot be pinched due to excessive lymphedema.
What are the cutoff values in for duration of reflux in duplex of lower extremities?
1sec for Femoral and Popliteal veins
500ms for the other veins (Deep femoral, Saphenous, Tibial and perforator veins)
What is the most appropriate treatment for post thrombotic syndrome with venous leg ulcer?
Debriding the ulcer and Compression therapy of 40-50mmHg stockings
What are the CEAP classification?
classify the physical findings associated with chronic venous insufficiency.
Clinical
0 - No visible signs
1 - Telangiectasias or reticular veins
2 - Varicose veins
3 - Edema
4a - Pigmentation and/or eczema
4b - Lipodermatosclerosis and/or atrophy
5 - Healed venous ulcer
6 - Open venous ulcer
A - Asymptomatic
S - Symptomatic
Etiology
C - congenital
P - primary
S - secondary (post thrombotic)
Anatomy
S - superficial
P - Perforator
D - Deep
Pathophysiology
R - reflux
O - obstruction
R,O - reflux and obstruction
N - no venous pathophysiology identifiable
What is the risk factor most associated with progression of CEAP clinical class of patients with varicose veins and chronic venous insufficirncy?
Prior deep vein thrombosis
What are the typical swelling areas of the leg in venous insufficiency?
Swelling is limited to the foot and ankle.
What should be considered if all the leg is swollen?
Venous outflow obstruction and/or lymphedema.
What is the normal standing venous pressue?
90mmHg
What is the normal venous pressure after exercise?
30mmHg
how long does it take in a healhy person for the venous pressure (AVP test) to return to 90% of normal standing pressure after exercise?
30 seconds
What is Ambulatory Venous Pressure test?
Gold standard for messuring venous hemodynamics.
Butterfly needle is placed in a dorsal pedal vein.
Baseline venous pressure is messured in standing.
10 tiptoe manuvers.
Recording of time to returen to 90% of baseline pressue.
25% with venous ulcers have normal AVP!!!
What are optional resultes of AVP and their meaning?
Normal venous pressure - 90mmHg and fall to 30mmHg around exercise.
Pressure not fall normaly - Calf pump not working effectively.
Fast return to standing pressure - reflux of deep or superficial veins.
Pressure rise rather than fall - deep veins occlusion.
What is Plethysmography test?
Noninvasive method of estimating changes in volume in an extremity and outflow. There are few diffecent methods but all messuring outflow.
Patients with normal outflow exhibit rapid emptying of their lower extremity veins.
Inflation of thigh pump to occlude outflow and fast deflation while messuring the venous pressure.
In normal subject (non occluded) the pressure drops fast to base line.
What is the sensitevity of Plethysmography in detection DVT?
~90% above knee DVT and 66% and less below knee
What is the rate of exsiting anterior accessory GSV?
anterior accessory GSV is the most common, found in
up to 14%
How many vulves in the GSV and in the SSV?
Each of the veins have the same number of vulves which is 7-10.
What is the rate of connection of SSV to SPJ within 5cm if the popliteal skin crease?
2/3
1/3 as high as 7cm above the crease.
What is a reticular vein?
thin-walled venules (blue) lying in the superficial compartment with 1-3mm diameters.
May connect to the saphenous and create network called lateral subdermic venous system (LSVS) and may connect to telangietasias in 88% of patients.
What is a Telangiectasias vein?
dilated venules (blue), capillaries, or arterioles (red) 0.1 to 1.0 mm in diameter.
Reticular veins are frequently “feeder” veins to
telangiectasias
What is the Venous Clinical Severity Score (VCSS) and the Villalta scale?
Scoring systems that assess severity of disease and
quality-of-life issues.
What is the primery point of primery and reccurent reflux in majority of patients?
SFJ mainly (~70%) and SSV (~20%).
What are the most recommended treatments for saphenous reflux?
Both Radiofrequency ablation (RFA) and Endovenous laser ablation (EVLA) are safe and efficacious.
What is the advantage of RFA and EVLA over open surgery and foam sclerotherapy?
“Success” rates were:
84% for RFA
94% for EVLA
78% for surgery
77% for foam sclerotherapy.
RFA and EVLA have less convalesce time, and decreased post procedural pain and morbidity.
They have more efficacy and cost-effective over sclerotheraphy.
What are the complications of EVLA
DVTs, 0% to 5.7%
skin burns, less than 1%
nerve injury, 0% to 22%
superficial thrombophlebitis, 0% to 25%.
Rear complication (both EVLA and in RFA) is arteriovenous fistula, commonly occurring where the external pudendal artery crosses posterior to the GSV.
Treatment of lymphangiosarcoma
Lymphangiosarcoma, or Stewart-Treves syndrome, can develop in the setting of chronic lymphedema.
Classically this would present in patients who had had a radical mastectomy with lymph node dissection. In modern times, this can present in any patient with chronic lymphedema. Although prognosis remains poor, surgical excision with amputation or wide local excision with adjuvant chemoradiation offers the best chance of survival. Compression and manual decongestive therapy are appropriate for lymphedema, but do not address the patient’s malignancy. Given the absence of distal disease and the patient’s otherwise good health, definitive treatment should be pursued.
Classification of primary lymphedema?
Primary lymphedema is further classified on the basis of genetics (familial vs. sporadic) and time of onset (congenital, praecox, tarda).
Time classification of primery lymphedema?
Congenital - present at birth or is recognized within the first year of life.
Praecox/Meige’s disease (most common) - onset of puberty until the third decade.
Tarda (10%) - after the age of 35 years
What is the most common cause of lymphedema in the western world?
Secondary.
Iatrogenic causes predominate.
What is the most common cause of lymphedema in the third world?
Secondary.
90% Filariasis - Wuchereia bancrofti (90%).
What are the clinical stages of lymphedema?
- Latent Phase: Excess fluid accumulates and fibrosis.No edema is apparent clinically.
- Grade I: Edema pits on pressure and is reduced largely or completely by elevation. No clinical evidence of fibrosis.
- Grade II: Edema does not pit on pressure and is not reduced by elevation. Moderate to severe fibrosis is evident on clinical examination.
- Grade III: Edema is irreversible and develops from repeated inflammatory attacks, fibrosis, and sclerosis of the skin and subcutaneous tissue. Elephantiasis.
What is the differeance between lipedema and lymphedema?
Lipedema is characterized by the deposition of a large amount of fatty tissue in the subcutaneous layers.
involves both legs and there is a sparing of the feet despite pronounced enlargement of the calves and thighs.
What is the gold standard and goal of treatment in lyphedema?
Mechanical therapy is the gold standard and includes self hygiene, compression techniques and physiotherapy.
Attention is directed to the reduction of limb swelling and prevention of secondary infections.
What is lymphedema?
various disease states characterized by the interstitial accumulation of protein-enriched fluid
What is the difference b/w high-input and low-output failure?
Give e.g. of each.
high-input
increased lymph prod > transport capacity even if lymph conduits normal. e.g. venous edema
low-output
pathologic condition compromises lymph flow
eg. hypoplasia/aplasia, abnormal valves
What is the major classification of lymphedema?
Primary and secondary
What is a sub-clssification of primary?
congenital
non-familial
familial (milroy’s)
Praecox (age 1-35)
non-familial
familial (meige’s disease)
Tarda (age >35)
What is a sub-clssification of secondary?
filariasis
lymph node excision
tumor invasion
infection
trauma
What condition can congenital lymphedema be associated too?
turner, klingelters, trisomy 21, noonans
what is most common/rare form of primary?
praecox common tarda rare (10%)
what is most common secondary?
filariasis followed by breast cancer
20-30% of breast cancer patients
What is the morphological classification of lymphedema?
aplasia–absence of collecting vessels
hypoplasia–diminished number
numerical hyperplasia–increased number
hyperplasia–increased number and valve incompetence
What is most common parasite associated with filariasis lymphedema? How transmitted?
Wuchereria bancrofti (90%) mosquito and poor sanitation