DVT in depth

1. DEEP VEIN THROMBOSIS
Moderator:
Prof Dr. VKS
Prof Dr. SKB
Presenter: Bikash Bk. Thapa

2. DEEP VEIN THROMBOSIS
 A thrombus is a mass formed from blood
constituents within a vessel or the heart during life.
 A venous thrombus is the formation of a semi-solid
coagulum within flowing blood in the venous
system.

3.  The incidence of DVT ranges between 5 and 9 per
10,000 person-years in the general population,
 and the incidence of VTE (DVT and PE combined)
is approximately 14 per 10,000 person-years.
 Major surgery have a significant incidence of
perioperative DVT (15 to 40%).
 Major trauma : 40- 80%
 Hip or knee surgery : 40- 60%
 Spinal cord injury : 60-80%

4. EPIDEMIOLOGY OF DVT
 occurs first time in about 1 to 2 persons per 1,000
 20 – 30% of general surgical patients
 Male :Female = 1:1
 This incidence increases with increasing age, doubling with
each decade of life after 40
 More than two thirds of these patients have DVT alone, and
the 30% will have symptomatic pulmonary embolism with
mortality of 17%

5.  50 to 60% of DVT are asymptomatic
 The recurrence rate with anticoagulation has been
noted to be 6% to 7% in 6 months
 DVT in upper extremity is less common- 5% of all
documented DVT but one third result in PE
 Upper limb DVT may be primary or secondary

6. Stasis
Activation of Coagulation
Vessel Damage
Virchow's Triad
PATHOPHYSIOLOGY

7. PATHOPHYSIOLOGY
 Starts as a platelet nidus, usually in the venous valves of
the calf.
 Platelet adhere to the endothelium and to each other
forming a projecting mass
 The liberation of thromboplastin initiates a chemical
cascade leading to coagulation
 If the rate of flow is slow red cells are entangled so that the
lumen is occluded
 In front and behind platelet mass, the blood stagnates
further formation of fibrin takes place, resulting in a large
solid coagulum

8. SEQUELS OF THROMBOSIS
 Fibrinolysis
 Organisation
 Calcification
 Incorporation
 Embolism

9.  A thrombus often develops in the soleal veins of the calf,
 Propagate and extend up to next venous branch and
break down to embolize
 Thrombus localise to calf have less tendency to
embolise than thromboi that extend to the thigh vens
 Aproximately 20% of cases of calf DVT propagate to the
thigh, and 50% of cases of thigh or proximal DVT
embolize

10. SEQUELE OF DVT
 DVT- Phlegmaisa alba dolens- Phlegmasia cerulea
dolens in 1 to 2 days- Secondary arterial
insufficiency venous gangrene in 1 to 2 days
 Inc capillary hydrostatic pressure leading to
massive intersital edema and hypovolemic shock-
 Venous gangrene leading to amputation
 PCD is assoc with amputation of 50%
 12-40% PE
 Mortality rate of 20%

11. RISK FACTORS
A. Malignancy
 Tumor cell activation of clotting cascade
 Indirect clotting activation
 Reactive thrombocytosis
B.Endothelial injury
 Adhesion of tumor cells
 Chemotherapeutic drugs
C. Venous stasis
 Immobility, venous obstruction, inc pressure, inc blood
viscosity
 Reduced clerance of activated clotting factors
 Endothelial hypoxia- inc expression of TF
D .OCP
 Odd ratio of 3-5 for risk of DVT

12. E. Hypercoagulable states
 Primary
 Dec activation of protein C
 Impaired heparin binding of antithrombin III
 Downregulation of membrane associated plasimin production
 Inc serum prothrombin lefels
 Decrease thrombogenic inhibitors (antithrombinIII, protein C,
Protein S
 Secondary
 Antiphospholipid syndrome
 Venous trauma
 Surgery
 Cancer
 Chemotherapy
 Myeloproliferative syndromes
 Heparin induced thrombopathy
 hyperhomocysteinemia

13. RISK FACTORS FOR DVT

14.  In pregnant women, it has an incidence of 0.5 to 7 per 1,000
pregnancies, and is the second most common cause of
maternal death in developed countries after bleeding
 general anesthesia and prior episode of DVT have a 5 times
increased risk
 Patients with acute MI who are not receiving anticoagulation have a
26-38% rate of DVT
 40% of postoperative neurosurgical patients develop DVT.
 Type A blood is associated with lower levels of antithrombin III and
higher levels of factor VIII than type O blood.
 Women of reproductive age with type A blood are 4 times as likely
to develop DVT.

15. PRESENTATION
 Pain n swelling of unilateral calf
 Bilateral is uncommon-30%
 Asymptomatic n may present as features of
pulmonary embolism
 Pleuritic chest pain, haemoptysis n SOB
 Phlegmasia alba dolens and phlegmasia cerulea
dolen

16. Phlegmasia alba dolens :
 Deep venous channels of the extremity are affected while
sparing collateral veins and therefore maintaining some
degree of venous return. Present with blanching of the
extremity, edema and discomfort
 Phlegmasia cerulea dolens:
 Occurs with extension of thrombus into the collateral venous
system, resulting in limb pain and swelling with cyanosis a
sign of arterial ischemia

17. PHYSICAL SIGN
 Pitting edema
 Dilated superficial veins
 stiff calf and tenderness over the course of the deep veins
 Erythema
 Bluish discoloration
 Absent or decreased pulse
 Homans’ sign – resistance (not pain) of the calf muscles to
forcible dorsiflexion –
 Pratt's sign: Squeezing of posterior calf elicits pain
 Low grade fever
 PE- cyanosis, dyspnoea, raised neck veins, a fixed split
second heart sound and a pleural rub

18. DIFFERENTIAL DIAGNOSIS
 Cellulitis, lymphangitis
 Lymphedema
 Ruptured Baker cyst
 Varicose veins
 Superfical thrombophlibitis

19. Score
(wells score)
Clinical Parameter Score
+1
Active cancer (treatment ongoing, or within 6 mo or palliative)
+1
Paralysis or recent plaster immobilization of the lower
extremities
+1
Recently bedridden for >3 d or major surgery <4 wk
+1
Localized tenderness along the distribution of the deep
venous system
+1
Calf swelling >3 cm compared with the asymptomatic leg
+1
Pitting edema (greater in the symptomatic leg)
+1
Previous DVT documented
+1
Collateral superficial veins (non varicose)
-2
Alternative diagnosis (as likely or greater than that of DVT)
WELLS SCORE FOR DVT

20. Total of Above Score
>3
High probability
1 or 2
Moderate probability
< 0
Low probability
WELLS SCORE

21. LAB
CBC
PT ,PTT , INR
ESR
D-dimer
ABG
Protein C , S Antithrombin III
LFT
RFT

22. IMAGING
 DUPLEX ULTRASOUND
 combines real-time B-mode ultrasound with pulsed
Doppler capability.
 HELICAL CT VENOGRAPHY
 CONTRAST VENOGRAPHY
 MRI
 OTHERS
 CHEST X-RAY
 ECHO
 PULMONARY ARTERIOGRAPHY
 V/Q SCAN

23. DUPLEX ULTRASONOGRAPHY
73%
Sensitivity in calf vein
95-97%
Sensitivity in proximal vein
95-98%
Specificity
lack of spontaneous flow
inability to compress the vein
absence of color filling of the lumen
by color flow DUS,
loss of respiratory flow variation,
Venous distension

24. DUPLEX ULTRASONOGRAPHY
Advantage
 helpful to differentiate
venous thrombosis
from hematoma, Baker
cyst, abscess, and
other causes of leg
pain and edema.
 Non-invasive
 inexpensive
Disadvantage
 Venous thrombi in
iliac and tibial vein are
difficult to visualize
 early n fresh thrombi
 not be able to
differentiate between
old and new clots

25. VENOGRCTAPHY/ CT VENOGRAPHY
(GOLD STANDERD)
o The gold standard is intravenous venography,
o A positive study result is failure to fill the deep
system with passage of the contrast medium into
the superficial system or demonstration of discrete
filling defects
o Similar sensitivity as Ultrasound

26. MRI
– In the second and third trimester of pregnancy,
MRI is more accurate than duplex
ultrasonography because the gravid uterus alters
Doppler venous flow characteristics.
– In suspected calf vein thrombosis, MRI is more
sensitive than any other noninvasive study.

27.  D-dimer testing
 D-dimer antibodies account for their high sensitivity for
venous thrombo embolism.
 D-dimer level may be elevated in any medical condition
where clots form. D-dimer level is elevated in trauma,
recent surgery, hemorrhage, cancer, and sepsis.
 The D-dimer assays have low specificity for DVT;
therefore, they should only be used to rule out DVT, not
to confirm the diagnosis of DVT.

28.  D-dimer results should be used as follows:
 A negative D-dimer assay result rules out DVT in
patients with low-to-moderate risk and a Wells DVT
score less than 2.
 All patients with a positive D-dimer assay result and all
patients with a moderate-to-high risk of DVT (Wells
DVT score >2) require a diagnostic study (duplex
ultrasonography).

29. TREATMENT
 Principles are:
 To prevent clot propa

30.  Major general ,
urological. Gyne.
Cardiothoracic,vascular
or neruological surgery
 Age > 40 yrs
 Mahor medical illness
 Major trauma or burns
 Minor surgery or trauma
in pat with previous DVT,
PE
 Orthopedic surgery or
amputation of LL
 Lower limb paralsis
 Major pelvic or abdominal
surgery for cancer
 Major surgery, trauma or
illness in pat with previous
DVT, PE, Thrombophillia
 Full limb paralysis
 Maojor limb amputation
Moderate risk High risk

31. Frequency of
Fatal PE
Frequency of
Proximal Vein
Thrombosis
Frequency of
Calf Vein
Thrombosis
Category
>1%
10-30%
40-80%
High-risk
0.1-1%
1-10%
10-40%
Moderate-
risk
<0.1%
<1%
<10%
Low-risk

32. PROPHYLAXSIS
 All patient admitted should be assessed for risk for DVT
 Overall, low-dose UFH and LMWH reduce the risk for
symptomatic and non symptomatic VTE by 60 to 70%.
 Low risk
 Graduated compression stockings, Early mobilisation and leg
elevation
 Moderate risk
 Leg elevation, early mobilization, and either graduated
compression stockings or s/c UFH or LMWH
 High risk
 Leg elevation, early mobilisation, TEDs, UFH or LMWH

33.  Heparin
 5,000 unit ,S/C 2 hours before surgery and every 8 or 12 hourly
 Graduated elastic compression (GEC)
 stockings reduce the incidence of asymptomatic DVT by
approximately 50-60%
 Intermittent pneumatic compression (IPC)
 reduces the incidence of asymptomatic DVT by approximately
69%
 Aspirin
 reduces DVT by 30% and PE by 50%
 Prophylactic insertion of IVC filters
 Fondaparinux has similar results like LMWH

34. • In the Women's Health Study, supplementation with
vitamin E (alpha-tocopherol, 600 IU every other day)
reduced the risk of venous thrombo embolism in women,
especially those with a prior history or genetic
predisposition.
• High-risk patients should also be prescribed a single
prophylactic subcutaneous 40 mg dose of enoxaparin
prior to a long plane trip (>6 h).

35. TREATMENT
 Principles are:
 To prevent clot propagation
 Reduce the risk of PE and
 Enhance the resolution of the clot to minimize the post –
thrombotic syndrome
 Options are
 Anticoagulants/ Pharmacotherapy
 Catheter directed intra-thrombus thrombolysis
 Inferior vena caval filters
 Venous thrombectomy

36. ANTICOAGULATION THERAPY
 HEPARIN
 Increases the binding of coagulatoin factors IXa, Xa,
XIa, XII and thrombin to antithrombin-III
 Discourage further clot formation and facilitate
endogenous clot lysis
 onset of action
 10-18 mins IV
 20-60 min S/C ( peak at 4-6 hrs n last up to 12 hrs)
 Half life – 90 mins
 Safe in pregnancy
 Monitoring done with APTT 6 hrly (1.5 to 2.5 times)
 Platelet count should be done every 3 days
 APTT >1.5 should be achieved with in 24 hrs

37. Heparinization
 Continous IV infusion
 Loading dose- 5000 to 10000 unit( 80 U/kg)
 Continuous infusion- 1300 units /hour (18 U/Kg)
 Intermittent intravenous adminstration
 70-100 units /kg every 4 hours
 Subcutaneous adminstration
 5000 unit every 8 0r 12 hourly
 Should be continued for 4-6 days
 Oral anticoagulant after 24 hours and overlapped for 4
days
 Heparin should be discontinued when INR is >2 for 2
consecutive days
 Warfarin is continued for minimum 3 months to maintain
INR between 2.0 to 4.5

38. Advantages of Low Molecular Weight Heparin
 Greater activity against factor Xa
 Lower risk of bleeding
 Longer half life(4-6 hrs)
 Produce little effect on test APTT or PT so no need
of monitoring
 Can be started simultaneously with warfarin
 Weight-based once- or twice-daily SC LMWH
injections
 Incidence of HIT is<2%
 Can be used as outpatient therapy
 Less recurrence (8.6% vs 6.9%)

39. Adverse affects are
 Harmorrhage- 5%
 Thrombocytopenia( HAAbs)
 1-5%
 Repeated exposure 21%
 HIT type I
 HIT type II
 Hypersensitivity
 hyperkalemia

40. WARFARIN
 Inhibits the enzyme vitamin K epodxide
 Thus indirectly inhibit the the synthesis of vitamin K
dependent clotting factors
 5mg orally
 Onset: 36 -48hrs
 Duration: 2-6 days
 Half life: 36-40hrs
 Bioavailability: 100%
 Can cross placenta/ appears in milk/
 The target INR 2 to 3
 Adverse affects
 Haemorrhage (0.5 to 1% per month)
 Skin necrosis
 Teratogenecity
 Liver damage

41.  Duration
 First attack- 3 mth
 Second attack- 1 year
 Third attack- life long
 Life time warfarin is aslo indicated for
 Thrombophilia
 Patients with first VTE and malignancy
 Recurrence rate is 2.6% for life long therapy

42. NEWER AGENTS
 Fondaparinux
 synthetic pentasaccharide
 Its five-polysaccharide sequence binds and activates
antithrombin, causing specific inhibition of factor Xa
 The drug is administered SC once daily with a weight-
based dosing protocol: 5 mg, 7.5 mg, or 10 mg for
patients weighing <50 kg, 50 to 100 kg, or >100 kg,
respectively
 Half life is 17 hrs
 The rates of recurrent VTE ranged from 3.8 to 5%, with
rates of major bleeding of 2 to 2.6%, for all treatment
arms

43.  Direct Thrombin inhibitors
 recombinant hirudin, argatroban, and bivalirudin
 bind to thrombin, inhibiting the conversion of fibrinogen
to fibrin as well as thrombin-induced platelet activation.
 reserved for (a) patients in whom there is a high clinical
suspicion or confirmation of HIT, and (b) patients who
have a history of HIT or test positive for heparin-
associated antibodies
 administered for at least 7 days, or until the platelet
count normalizes. Warfarin may then be introduced
slowly, overlapping therapy with a DTI for at least 5 days

44. LONG TERM ANTI THROMBOTIC THERAPY FOR
DVT

45. INFERIOR VENACAVAL FILTER
 Kimray-Greenfield filter in 1973
 Traps emboli as small as 3mm
 Made of titanium or nickel titanium alloy
 Placed percutaneously under LA via the
common femoral, internal juglar or antecubital vein
 Positioned in the infra-renal cava
 20 years follow up – 96 % patency
 Complications associated with IVC filter placement
include insertion site thrombosis, filter migration, erosion
of the filter into the IVC wall, and IVC thrombosis.
 The rate of fatal complications is <0.12%

46.  Absolute indication are
 DVT or PE with contraindication to anticoagulation therapy
 prior hemorrhagic stroke
 Recent neurosurgical procedure or major surgery
 Multiple trauma
 Active internal bleeding
 Intracranial neoplasm
 Bleeding diathesis
 Pregnancy
 DVT or PE having complication with anticoagulation therapy
 Failure of anticoagulation therapy
 Free-floating iliofemoral or caval thrombus
 Relative indication
 Prior history of chronic pulmonary HTN
 Morbidly obese with BMI >55

47. Catheter Directed Intra-thrombus thrombolysis
 Placement of thrombolysis catheter within the clot
 Rapid clearance of the DVT
 SITE: IJV, contralateral CFV, popliteal, tibial vein
 Thrombolytic drugs: streptokinase, alteplase , reteplase, and
tenecteplase, urokinase
 convert plasminogen to plasmin, which leads to the degradation of fibrin.
 Higher success in acute DVT n new onset DVT and upper limb
 < 10 days with 34% and > 10 days 19%
 1 year patency 79% for complete lysis and 32% for partial lysis
 Overall one year patency is 60%
 Major bleeding -11%
 Mortality 0.4%
 Contraindicated in:Recent surgery, active or recent bleeding, bleeding
diathesis, pregnancy and cerebral disease

48. VENOUS THROMBECTOMY
 Inidcation
 Phlegmasia alba dolens
 Phlegmasia cerulea dolens with impending venous gangrene
threatening to the patient’s life and limb
 Failed or contraindicated anticoagulation and thrombolysis
 If the patient has phlegmasia cerulea dolens, a fasciotomy
of the calf compartments is first performed
 Useful in relatively young patient who has cause other
than malignant dis for the DVT

49.  An intraoperative completion venogram is obtained to
determine if any residual thrombus or stenosis is
present.
 Post op managed with limb elevation, calf exercise,
compression stockings, antibioitc therapy, heparin for 5
days and warfarin for 6 months or life long
 Good result if performed with in 7-10 days of event
 Mortality rate is 1%
 Intraoperative PE occurs in 20%
 10 yrs follow up patency 77%
 Severe PCD and venous gangrene have poor outcome

50. TREATMENT IN PREGNANCY
 The treatment of DVT in pregnancy is similar to
the treatment of non pregnant.
 Heparin SC or small pump infusion
 Avoid warfarin in pregnancy If warfarin therapy
is essential, it should be avoided at least during
the first trimester (because of teratogenicity)
and from about 2 to 4 weeks before delivery to
reduce risk of hemorrhagic complications
 Compression stockings

51. COMPLICATIONS OF DVT
• pulmonary embolism
• post-thrombotic syndrome
• occurs in 15% of patients with deep vein
thrombosis (DVT). It presents with leg oedema,
pain, nocturnal cramping, venous claudication,
skin pigmentation, dermatitis and ulceratiaion
(usually on the medial aspect of the lower leg).

52. High clinical pretest probability- DVT likely
Doppler ultrasound
Ultrasound positive for DVT
Diagnoses of DVT confirmed
Begin treatment
Ultrasound negative
for DVT
D-Dmer test (if available and reliable)
Otherwise skip
to repeat ultrasound
D-Dimer positive Repeat
ultrasound in 1 week
D-Dimer negative
DVT ruled out
Repeat ultrasound positive for DVT
Diagnoses of DVT confirmed
Begin treatment
Suspect DVT
Low clinical pretest
probability- DVT likely
Consider starting with D-dimer
test first
(if available and reliable )
Or skip to ultrasound
D-dimer positive
D-Dimer negative
DVT ruled out
Doppler ultrasound
Ultrasound positive for DVT
Diagnose of DVT confirmed
Begin treatment
Ultrasound negative
for DVT
DVT ruled out
(consider repeat
ultrasound if
D-dimer not available)