This document discusses deep vein thrombosis (DVT) prophylaxis, treatment, and anesthetic considerations. It defines DVT as the formation of thrombus in the deep veins of the leg. It outlines risk factors for DVT including immobilization, surgery, trauma, and cancer. Signs and symptoms, diagnosis, and treatment options are discussed. Mechanical prophylaxis includes graduated compression stockings and intermittent pneumatic compression. Pharmacological options include heparin, low molecular weight heparin, warfarin, and newer oral anticoagulants. Regional anesthesia considerations are discussed when patients are on anticoagulation.

1. DVT PROPHYLAXIS ,
TREATMENT &
ANAESTHETIC
CONSIDERATIONS
PRESENTER- DR NANDINI DESHPANDE
GUIDE- DR PIYUSH MITTAL

2. DEFINITION:
The formation of thrombus in the deep
veins of the leg.

3. OVERVIEW:

4. BACKGROUND:
It is a common, yet preventable perioperative
complication.
Highest risk in critical care and spinal cord injury
patients- 60-80%
Post- Ortho Procedures: 40-60%
Post-General Surgery/ Obstetric- 15-40%
Variable for Urologic Cases

5. VIRCHOW’S TRIAD

6. SITES FOR DVT:
Ileo-femoral veins (80% cases)
Popliteal veins
Calf veins(extending proximally
in 30% cases)
 Inferior Vena Cava(rarely)

8. CLINICAL FEATURES:
Tenderness occurs in 75% confined to the calf muscles or
over the course of the deep veins in the thigh.
 Warmth or erythema of skin can be present over the area
of thrombosis.
Clinical signs and symptoms of pulmonary embolism as
the primary manifestation occur in 10% of patients with
confirmed DVT[ one of the fatal emergencies encountered
by an anaesthetist].
 The pain and tenderness associated with DVT does not
usually correlate with the size, location, or extent of the
thrombus

9.  Many patients are asymptomatic
Pedal Edema, principally unilateral, is the most
specific symptom
Leg pain (50%) & tenderness
 Pain can occur on dorsiflexion of the foot (Homan’s
sign)
Warmth or erythema of skin Can be present
 Moses sign- tenderness elicited by squeezing or
pressing firmly on sole of foot or calf.

12. DIFFERENTIAL DIAGNOSIS:
 Cellulitis
lymphangitis
Lymphedema
Postphlebitic syndrome
Ruptured Baker cyst
Varicose veins
Superficial thrombophlebitis

13. DIAGNOSIS:
History & clinical features
Physical examination(work up)
Probability scoring (well’s score)
Blood test
D-dimer test
Other blood test
Imaging study
MRI , U/S , venography

14. PHYSICAL EXAMINATION:
 Homans' test Dorsiflexion of foot elicits pain in
posterior calf. Warning: it must be noted that it is of
little diagnostic value and is theoretically dangerous
because of the possibility of dislodgement of loose clot.
Pratt's sign: Squeezing of posterior calf elicits pain.

17. INCIDENCE:
 Venous thromboembolic diseases in hospitalised patients results in substantial
mortality, morbidity and healthcare resource use.
 The incidence of VTE in general surgical patients not receiving prophylaxis ranges
from 15-30% for deep vein thrombosis (DVT) and 0.2-0.9% for pulmonary embolism.
 The rate of fatal pulmonary embolism is 0.1-0.8% after elective general surgery, 2-3%
after elective hip replacement and 4-7% after repair of a fractured hip if prophylaxis
is not administered.
 Autopsy studies have shown that 5–10 % of hospital deaths are attributable to
pulmonary embolism.

19. RISK FACTORS FOR DVT:

21. 21

22. RISK STRATIFICATION:
Patients should be stratified preoperatively for their
risks of perioperative venous thromboembolism, so
appropriate measures can be implemented on the
day of surgery.

23. LOW RISK MINOR SURGERY IN PATIENTS < 40 YEARS OF AGE
WITH NO ADDITIONAL RISK FACTORS PRESENT
MODERATE RISK MINOR SURGERY IN PATIENTS WITH
ADDITIONAL RISK FACTORS PRESENT
OR SURGERY IN PATIENTS 40-60 YEARS OLD
WITH NO ADDITIONAL RISK
HIGH RISK SURGERY IN PATIENTS >60 YEARS OLD
OR SURGERY IN PATIENTS 40-60 YEARS OLD WITH
ADDITIONAL RISK FACTORS
HIGHEST RISK SURGERY IN PATIENTS >/= 40 YEARS OLD WITH
MULTIPLE RISK FACTORS, HIP OR KNEE
ARTHROPLASTY, HIP FRACTURE SURGERY, MAJOR
TRAUMA OR SPINAL CORD INJURY

24. RISK STRATIFICATION ACCORDING TO THE
TYPE OF SURGERY
•Laproscopic cholecystectomy &
appendicectomy
•Inguinal herniorraphy, TURP
•B/L mastectomy
LOW RISK
•Gynaecological [non-malignant]surgery
•Cardiac, thoracic surgery, bariatric
surgery
•Spinal tumour surgery
MODERATE
RISK
•Open-abdominal surgery
•Open-pelvic surgeryHIGH RISK

25. MANAGEMENT : ALL PATIENTS:
 Avoid dehydration unless there is a specific clinical reason.
 Encourage early mobilization.
 The affected extremity should be elevated above the level of the heart
until the oedema and tenderness subside .
 Aspirin or antiplatelet agents should not be considered adequate
prophylaxis.
 Consider temporary IVC filters for patients at a very high risk of VTE
(eg: active malignancy or previous VTE event) & if there are contra-
indications to pharmacological and mechanical prophylaxis. These are
devices which can be inserted into the inferior vena cava to prevent the
development of a pulmonary embolus.

26. CHOICE OF PROPHYLAXIS: MECHANICAL
Several methods are available: •Graduated compression stockings
are effective in decreasing the risk of DVT, either alone or in
combination with pharmacological prophylaxis in high-risk patients.
Thigh-length graduated compression/anti-embolism stockings can be
used unless contra-indicated (e.g. in patients with established
peripheral arterial disease or diabetic neuropathy). They should be
used routinely for surgical inpatients. If thigh-length stockings are not
appropriate (for reasons of fit or compliance) knee-length stockings may
be used instead.
 Stocking compression profile should be equivalent to the Sigel profile (a
pressure profile for elastic stockings) and approximately: 18 mm Hg at
the ankle ,14 mm Hg at the mid-calf & 8 mm Hg at the upper thigh .

27. Staff trained in the use of compression stockings should
show the patient how to wear them correctly, monitor their
use and provide assistance when needed.
Patients should be encouraged to wear stockings from
admission until they return to their normal level of
mobility.
Intermittent pneumatic compression or foot impulse
devices may be used instead of, or as well as, graduated
compression stockings while patients are in hospital.

28. MECHANSIM & EFFECTS:
MECHANISM: The pump provides intermittent cycles of
compressed air which alternately inflate and deflate the
chamber garments.
Effects :
Increases venous return
Decreases venous stasis
Stimulates fibrinolytic activity which causes dissolution of
clot and prevention of thrombus formation

31. PHARMACOLOGIC
AL
CLASSIFICATION:
 Anticoagulants and
thrombolytics are
commonly used for
prophylaxis and
treatment of DVT.
 Antiplatelet drugs are
more commonly used in
patients with coronary
artery disease,
PVD,CVA & other
ischemic conditions to
prevent formation of
localized thrombus .

32. PHARMACOLOGICAL PROPHYLAXIS:
ANTICOAGULANTS:
Anticoagulants prevent thrombous propagation
& allow endogenous lytic system to operate.
Aim :prevention of pulmonary embolism , since
in the early stages the thrombus maybe loose &
poorly adherent to the vessel wall.

33. CONTRAINDICATIONS:
Recent surgery-especially to eye or CNS.
Pre-existing hemorrhagic state like Liver disease,
renal failure, Hemophilia &Thrombocytopenia
Pre-existing structural lesions like Peptic Ulcer
Recent cerebral hemorrhage

34. HEPARIN:
Mech. Of action :
 Standard Heparin (SH) : It produces its anticoagulant
effect by potentiating the activity of anti-thrombin
which will inhibit procoagulant enzymatic activity of
factors IIa ,VIIa ,IXa ,Xa ,Xia
LMWH augment anti-thrombin activity against factor
Xa.
There are different preparations of heparin used in IV,
SC forms .

35. PARENTERAL- UNFRACTIONATED
HEPARIN[UFH]
Derived from porcine intestinal mucosa
Promotes Anti-Thrombin mechanism and inactivates
Thrombin and Factor Xa
DVT Prophylaxis dose -5,000 U SC Q8-12H , aPTT
monitoring not needed
 Therapeutic Dosing I /v Bolus (80U/Kg) + I /v continuous
infusion (18U/Kg/hr), aPTT monitoring is needed in case of
prolonged IV infusion.
Safe in patients with Renal Dysfunction

36. PARENTERAL- LMWH [ENOXAPARIN,
TINZAPARIN, DALTEPARIN]
Produced by chemical or enzymatic cleavage of UFH
Inactivates factor Xa to a greater extent than Thrombin.
Minimally prolongs the aPTT
 Factor Xa monitoring is required in Renal dysfunction,
Obesity and Pregnancy
DVT Prophylaxis dose -Enoxaparin 40 mg SC once daily for 8-
12days
 Drug of choice in pregnant women requiring long term
anticoagulation for thrombosis and in those with mechanical
heart valves

37. PARENTERAL LMWH:
 ENOXAPARIN 1 mg/Kg SC Q12H
 TINZAPARIN 175 IU/Kg SC daily
DALTEPARIN 200 IU/Kg SC daily
 Heparin…(IV) as an initial bolus of 7500 to 10,000
IU followed by a continuous infusion of 1000 to
1500 IU/h.
Drug of choice in cancer patients and in those with
failed oral anticoagulation.

38. The dose and frequency is controlled by aPTT [ normal value-
33 to 35 sec] measurement which is kept at 50-80 sec or 1.5-
2.5 times the patient’s pretreatment value.
If this test is not available whole blood clotting time should be
measured and kept at 2 times the normal value.
 After a constant maintenance infusion of 18 U/kg is initiated,
the aPTT is checked 6 hours after the bolus and adjusted
accordingly.
 The aPTT is repeated every 6 hours until 2 successive aPTT’s
are therapeutic.
 Thereafter, the aPTT is monitored every 24 hours as well as
the hematocrit and platelet count.

39. FONDAPARINUX
Synthetic pentasaccharide structurally similar to
Heparin
 Selective Factor Xa Inhibitor
Monitoring of factor Xa levels similar to LMWH
(renal dysfunction)
Dosing -FONDAPARINUX 7.5 mg SC daily
Half- life- 18 to 20 hours.

43. ADVANTAGES OF LMWH OVER UFH:
LMWH has a high bioavailability after SC injection so its
given either as a fixed or weight-related dose . Therefore
,The plasma LMWH level does not need to be measured.
The incidence of thrombocytopenia is less with LMWH
than SC Heparin.
LMWH is reported to be as effective as or better than SH
in preventing extension or recurrence of venous
thrombosis.

44. ADVERSE EFFECTS OF
HEPARIN:
 Bleeding
 Osteoporosis (inhibits osteoblasts, activates
osteoclasts) –> 3 months, > 20,000 units qd
Thrombocytopenia- Type I HIT & Type II HIT (3-
5%)
Skins lesions- urticaria, papules, necrosis
Hypoaldosteronism, hyperkalemia

45. HEPARIN CONTRAINDICATIONS:
 Bleeding disorders, HIT
 Severe hypertension, threatened abortion,
piles
 SABE, large malignancies, Tuberculosis
Ocular and neurosurgery, LP
Chronic alcoholics, cirrhosis, renal failure

46. WARFARIN:
Dose- starts from 5 mg PO daily. It is available in various doses of
1mg, 2mg…
Acts by inhibiting Vitamin K reductase enzyme, thereby depleting
Vitamin K dependent clotting factors II, VII, IX and X.
 Good oral absorption but requires 4-5 days to achieve full
anticoagulant effect
Combine with parenteral till INR reaches at least 2-2.5
Monitor INR twice weekly for first 2 weeks, then weekly for 2 weeks,
then less frequently
Reversal of action- Vitamin K, FFP & prothrombin concentrates

49. OTHER USES
OF WARFARIN:

50. RECOMMENDED INR:
Recommended INR for various indications are
as follows:
Prophylaxis of DVT - 2 - 2.5
Treatment of DVT - 2 - 3
Recurrent VTE, MI, prosthetic heart valve
disease- 3-3.5

53. NEWER ANTICOAGULANTS:
DABIGATRAN: It is a direct thrombin inhibitor. Reviewed
and approved for prevention of DVT after THR & TKR in a
NICE technology appraisal published in September 2008.
RIVAROXABAN: It inhibits activated factor Xa. It was
approved for prevention of DVT after THR & TKR in a
NICE technology appraisal published in April 2009.
They have been approved for treatment of venous
thromboembolism[VTE] and pulmonary embolism[PE].

55. Advantages over warfarin:
- rapid onset of action
- no monitoring required
- reduced risk of bleeding
Disadvantages:
- lack of monitoring ability
- lack of antidote (maybe)
- cost
Their increased use poses new challenges when
bleeding complications occur

57. ALOGARITHM FOR USE OF
ANTICOAGULANTS IN DVT:

58. OTHER OPTIONS IF DRUGS
ARE CONTRAINDICATED???
IVC FILTERS
SURGERY

60. IVC FILTER:
INDICATIONS OF PLACEMENT:
Severe haemorrhagic complications due to use of
oral anticoagulants
Absolute contraindications to use of oral drugs
Failure of oral anticoagulant therapy such as new
or recurrent venous thrombosis

62. SURGERY:
INDICATIONS:
Anticoagulant therapy is ineffective
Unsafe
Contraindications
The major surgical procedures for DVT are clot
removal and partial interruption of the inferior
vena cava to prevent pulmonary embolism.

63. ANAESTHETIST AND DVT???WHY IS IT
IMPORTANT??
Careful while using neuraxial anaesthesia when the patient is on
anticoagulants.
Medicolegal concerns when regional anaesthesia and blocks are
used inappropriately when the patient is still on anticoagulants
and if they are used against the specific time frame of these
drugs.
Risk of pulmonary thromboembolism [PE] is high if DVT
prophylaxis in not given properly in high-risk patients.
Regional anaesthesia decreases the risk of DVT if given properly
and after withholding the anticoagulants as per their half-life.
GA poses 5 times more risk than RA in causing DVT.

64. REGIONAL ANAESTHESIA
CONSIDERATIONS IN PATIENTS ON
ANTICOAGULANTS:

65. There is a significant risk of epidural haematoma
which can lead to neurological deficits due to
continuation of perioperative anticoagulants when
neuraxial block is planned.
The morbidity caused due to use of neuraxial
anaesthesia is deeply concerning and medicolegal more
than the mortality of the patient due to DVT.
Hence, the standard protocol devised by AMERICAN
SOCIETY OF REGIONAL ANAESTHESIA[ ASRA]
guidelines are most widely practiced.

67. OPTIMAL DURATION OF
PROPHYLAXIS FOR DVT:

68. SUMMARY:
 If you deal with the risk factor early, DVT can be
prevented early
 Early detection & diagnosis can prevent
complications
DVT is 2nd cause of death in pregnancy
Well’s score& D-dimer and use of U/S can
diagnose DVT
PE& post thrombotic syndrome is the most
common and fatal complication

69. GUIDELINES TO BE FOLLOWED IN
ACCORDANCE WITH NABH INSPECTON
[8-10 MARCH 2018]