Venous thrombosisVenous thrombosis

By Dr. Sabir M. AmeenBy Dr. Sabir M. Ameen

Predisposing factorsPredisposing factors

11. Patient. Patient: a) age: : a) age: >40 >40 b) obesity b) obesity c) varicose veins c) varicose veins d) previous DVT d) previous DVT e) OCP e) OCP f) pregnancy/puerperium f) pregnancy/puerperium g) dehydration g) dehydration

h) immobilityh) immobility2. 2. SurgicalSurgical: :

a) if >30 min duration a) if >30 min duration b) abdominal or pelvic b) abdominal or pelvic c) orthopedic to lower limb c) orthopedic to lower limb

Pred. fact.Pred. fact.

3.3. Medical Medical: a) MI/HF : a) MI/HF b) IBD c) malignancy d) Nephrotic b) IBD c) malignancy d) Nephrotic syn e) pneumoniasyn e) pneumonia

4. 4. HematologicalHematological: a) PV b) ET c) PNH : a) PV b) ET c) PNH d) myelofibrosis d) myelofibrosis

5. 5. Anticoagulant deficiencyAnticoagulant deficiency: a) : a) antithrombin b) protein C c) protein S d) antithrombin b) protein C c) protein S d) factor V Leiden e) prothrombin mutation.factor V Leiden e) prothrombin mutation.

6. 6. Antiphospholipid syndromeAntiphospholipid syndrome: : a) lupus anticoagulant b) anticardiolipin a) lupus anticoagulant b) anticardiolipin AbAb

Venous thrombosisVenous thrombosis

VT: arise either because of damage to, or VT: arise either because of damage to, or pressure on veins (e.g. varicose veins or pressure on veins (e.g. varicose veins or pelvic tumor) , or as a result of changes in pelvic tumor) , or as a result of changes in plasma or cellular elements of blood.plasma or cellular elements of blood.

When thrombosis occur in an individual When thrombosis occur in an individual under 40 yr of age, particularly if there is a under 40 yr of age, particularly if there is a family history of thrombosis, investigations family history of thrombosis, investigations for a predisposing blood abnormality for a predisposing blood abnormality should be undertaken.should be undertaken.

Wells CriteriaWells Criteria

WellsWells

Low probability (-2-0) = 3-13%Low probability (-2-0) = 3-13% Moderate probability (1-2) = 17-38%Moderate probability (1-2) = 17-38% High probability (>2)= 60-75%High probability (>2)= 60-75%

Special InvestigationsSpecial InvestigationsTestTest AdvantagesAdvantages DisadvantagesDisadvantages

ContrastContrast ““Gold standard”Gold standard” InvasiveInvasive

VenographyVenography Sensitivity Sensitivity ~~ 100% 100% Requires specialized Requires specialized equipmentequipment

   Easily interpretableEasily interpretable Rare, but serious side effectsRare, but serious side effects

MRIMRI Highly accurateHighly accurate ExpensiveExpensive

   Safe during pregnancySafe during pregnancy Not readily availableNot readily available

   Non-invasiveNon-invasive   

CTCT Non-invasiveNon-invasive Limited dataLimited data

   Can diagnose pelvic Can diagnose pelvic DVTDVT   

   Concurrently exclude PEConcurrently exclude PE   

UltrasonographyUltrasonography Highly accurateHighly accurate Not accurate for calf or pelvic Not accurate for calf or pelvic DVTDVT

   Non-invasiveNon-invasive Complete study is time Complete study is time consumingconsuming

D-DimerD-Dimer Rapid laboratory studyRapid laboratory study Only used to rule-out Only used to rule-out DVTDVT

   Can aide in exclusion of Can aide in exclusion of DVTDVT

  

Management of Management of thromboembolismthromboembolism

Indications for anticoagulation:Indications for anticoagulation:

A.A. HeparinHeparin: : 1. Treatment & prevention of DVT1. Treatment & prevention of DVT2. Pulmonary embolism2. Pulmonary embolism3. post-thrombolysis for MI3. post-thrombolysis for MI4. unstable angina4. unstable angina5. acute peripheral arterial occlusion5. acute peripheral arterial occlusion

Indications of warfarin RxIndications of warfarin Rx

1)1) prophylaxis against DVTprophylaxis against DVT2.2. treatment of DVT & PEtreatment of DVT & PE3.3. arterial embolism arterial embolism 4.4. AF with stroke risk factorsAF with stroke risk factors5.5. mobile mural thrombus on echo post-MImobile mural thrombus on echo post-MI6.6. extensive anterior MI( all these INR= extensive anterior MI( all these INR=

2.5)2.5)7.7. recurrent DVT recurrent DVT 8.8. mechanical prosth heart valves( latter mechanical prosth heart valves( latter

two INR=3.5)two INR=3.5)

Contraindications to Contraindications to anticoagulationanticoagulation

1. Recent surgery( esp. to eye or CNS)1. Recent surgery( esp. to eye or CNS)2. pre-existing hemorrhagic 2. pre-existing hemorrhagic

condition( e.g. liver disease, RF, condition( e.g. liver disease, RF, hemophilia, thrombocytopenia)hemophilia, thrombocytopenia)

3. Peptic ulcer3. Peptic ulcer4.Recent cerebral hemorrhage4.Recent cerebral hemorrhage5. Uncontrolled HT5. Uncontrolled HT6. Dementia and frequent falls in old 6. Dementia and frequent falls in old

ageage

HeparinHeparin

Standard (unfractionated) heparin (SH) Standard (unfractionated) heparin (SH) produces its anticoagulant effect by produces its anticoagulant effect by potentiating the activity of antithrombin potentiating the activity of antithrombin which inhibits the procoagulant enzymic which inhibits the procoagulant enzymic activity of factors IIa, VIIa, IXa, Xa, and activity of factors IIa, VIIa, IXa, Xa, and XIa.XIa.

Low-molecular weight heparin ( LMWH) Low-molecular weight heparin ( LMWH) augments antithrombin activity augments antithrombin activity preferentially against factor Xa. LMWH preferentially against factor Xa. LMWH does not prolong PTT( unlike SH), and does not prolong PTT( unlike SH), and injections need only be given once daily injections need only be given once daily SC and no monitoring is required, many SC and no monitoring is required, many pts can be treated at home.pts can be treated at home.

Heparin…cont.Heparin…cont.

SH is reserved for treating pts with very SH is reserved for treating pts with very severe, life-threatening TE e.g. major PE severe, life-threatening TE e.g. major PE giving rise to hypoxia or hypotension.giving rise to hypoxia or hypotension.

Dose: loading dose of 5000 U i.v, followed Dose: loading dose of 5000 U i.v, followed by a continuous infusion of 20U/kg/hr by a continuous infusion of 20U/kg/hr initially. PTT done after 6 hr, and if initially. PTT done after 6 hr, and if satisfactory daily thereafter. The aim is satisfactory daily thereafter. The aim is to keep PTT 1.5-2.5 times the control to keep PTT 1.5-2.5 times the control time.time.

Heparin…cont.Heparin…cont.

Half-life of heparin is 1 hr, and if pt bleeds, it Half-life of heparin is 1 hr, and if pt bleeds, it is sufficient just to discontinue the is sufficient just to discontinue the infusion; however, if bleeding is severe , infusion; however, if bleeding is severe , the excess can be neutralised with i.v the excess can be neutralised with i.v protamine. Treatment with either SH or protamine. Treatment with either SH or LMWH should continue for 6-8 days, and it LMWH should continue for 6-8 days, and it is appropriate to start warfarin therapy at is appropriate to start warfarin therapy at the same time as heparin, and heparin the same time as heparin, and heparin should be contiued until INR is should be contiued until INR is >2.0 for 2 >2.0 for 2 consecutive days.consecutive days.

WarfarinWarfarin

It inhibits vit. K-dependent carboxylation of It inhibits vit. K-dependent carboxylation of factors II, VII, IX and X in the liver.factors II, VII, IX and X in the liver.

Dose: loading 10 mg orally on the first day, Dose: loading 10 mg orally on the first day, and subsequent daily doses depending on and subsequent daily doses depending on the INR. If single DVT it is given for 3-6 the INR. If single DVT it is given for 3-6 mon, if two or more it should be continued mon, if two or more it should be continued for life. Bleeding is the most common side for life. Bleeding is the most common side effect of warfarin: 0.5-1.0%/yr. If INR is effect of warfarin: 0.5-1.0%/yr. If INR is above therapeutic level stop warfarin and above therapeutic level stop warfarin and give a small dose of vit.k e.g. 5 mg orally give a small dose of vit.k e.g. 5 mg orally or 2 mg by slow i.v inj. If the pt bleeds, or 2 mg by slow i.v inj. If the pt bleeds, give vit. Kgive vit. K¹¹ 1-5 mg slowly i.v, and 1-5 mg slowly i.v, and

Warfarin..cont.Warfarin..cont.

If bleeding is serious , give coagulation If bleeding is serious , give coagulation concentrate containing factors II, VII, concentrate containing factors II, VII, IX and X (50U/kg)or, if unavailable, IX and X (50U/kg)or, if unavailable, FFPFFP

Prevention of venous Prevention of venous thrombosisthrombosis

Full-length graduated compression stockingsFull-length graduated compression stockingsSH or LMWHSH or LMWHIt should be started preop and continued until the pt It should be started preop and continued until the pt

is fully mobileis fully mobileConditions: A) moderate risk of DVT: 1. major Conditions: A) moderate risk of DVT: 1. major

surgery in pts surgery in pts >40yr or with other risk factors, 2. >40yr or with other risk factors, 2. major medical illness: e.g HF, chest infection, major medical illness: e.g HF, chest infection, malignancy, IBDmalignancy, IBD

B) High risk of DVT: 1. hip or knee surgery, 2. major B) High risk of DVT: 1. hip or knee surgery, 2. major abdominal or pelvic surgery( for malignancy or abdominal or pelvic surgery( for malignancy or with Hx of DVT or known thrombophilia)with Hx of DVT or known thrombophilia)