DEEP VEIN THROMBOSIS (DVT)
See picture in slide 4
2,Antithrombin III deficiency
3,Pregnancy and the postpartum period-
4,Oral contraceptives and hormone replacement therapy-
5,Antiphospholipid antibody syndrome-
6,Protein C and protein S are vitamin K-dependent-
7,Factor V Leiden-
(The prevalence of DVT in women receiving oral contraceptives of 1 to 3 in 10,000)
most common inherited hypercoagulable condition.
present in 12% to 33% of patients with spontaneous DVT .
protein that is needed for blood to clot properly.
Too much clotting power can lead to the formation of blood clots. True or False
Surgery within 3 months
Stroke, paralysis of extremities
History of DVT
Central venous catheters
(Inflammatory bowel disease ,Sickle cell anemia ,Marked leukocytosis in acute leukemia )
Things that can’t be removed that prohibits scanning of the area
prevents spontaneous clotting.
Prothrombin (plasma protein) is activated. It converts prothrombin to thrombin.
Thrombin converts fibrinogen to fibrin threads and it forms a clot.
see picture slide 21
Platelets become trapped behind the valve cusps due to flow recirculation
Platelets can stick to the collagen layer of the venous wall and may accumulate
Estrogen (replacement therapy or contraceptives) alters the state of coagulation.
-Superficial veins (GSV, LSV)
-Muscular veins (gastrocnemius and soleal sinus)
-Venous confluences (bifurcations).
-Acute onset pain
-Persistent leg swelling
-Hyperpigmentation (hard areas)
-Activate the body’s own clot dissolving (“fibrinolytic”) system.
When the body’s clot dissolving system starts to dissolve the clot, It leads to the production of fibrin fragments
Negative (normal) d-Dimer result, that almost rules out the possibility that the patient doesn’t have a blood clot actively forming
-negative (normal) d-Dimer result, that almost rules out the possibility that they have a blood clot actively forming
-Venous imaging help to determine presence or absence of thrombus (Chronic or Acute)
-The relative risk for the thrombus dislodging and traveling to the lung.
Clots within the superficial veins are more likely to produce a clinically significant pulmonary embolism because these clots are usually larger than those in the deep system
Clots within the deep veins are more likely to produce a clinically significant pulmonary embolism because these clots are usually larger than those in the superficial system
Because they are surrounded by muscle, the chance of the clot being dislodged during muscle contraction is higher than for a clot in the superficial veins.
Their job is to be the primary source for returning blood to the heart
Their job is not to be the primary source for returning blood to the heart
When the body needs to cool down, they enlarge to shunt large amounts of warm blood to the skin so that heat escapes the body.
Examination of the superficial veins is still an important part of a complete evaluation of the lower extremity.
There is also potential danger that a superficial vein clot can extend into the deep system.
-When they do not function, blood can pool at the skin level and chronic stasis changes and even ulcers may result.
The newer the clot, the more likely it is to embolize
– Poorly attached thrombus
– Spongy-texture thrombus
– Dilated vein (when totally obstructed)
-Rigid texture of thrombus
-Contracted vein (if totally obstructed)
-Thickened vein walls
When a thrombus has just formed, it is very faintly echogenic—almost invisible.
Transverse imaging should be performed with gray scale when performing venous duplex examination?
If the “cuts” are too far apart, a major section of vein containing thrombus can be missed. As a rule, the smaller the cuts, the less chance there is of missing a thrombus.
-Add color and pulsed Doppler
Substituting longitudinal views with color Doppler for the transverse compression views will result in missing partially obstructive thrombus.
Compression being limited by a nearby bone, and other factors.
In the case where the vein is not compressing, but thrombus cannot be seen directly (poor views or views of very small or deep structures).
It is taken by mouth beginning immediately upon the diagnosis of pulmonary embolism, but may take up to week for the blood to be appropriately thinned or anticoagulated
Iliofemoral venous thrombectomy
see slide 71
The dye has to be injected constantly via a catheter, making it an invasive procedure. Normally the catheter is inserted by the groin and moved to the appropriate site by navigating through the vascular system.