Deep Vein Thrombosis (DVT)

Last updated 05.10.12

 

Index

 

Definition

-  Venous thrombus formation in the deep veins, usually of lower limb

 

Features

-  May thomboembolise --> right heart --> lung

-  Cause of 80% PE

-  Usually from deep veins of leg

-  Right heart --> left heart via patent foramen ovale --> carotids --> stroke (rare)

-   Paradoxical stroke

-  More common in >40yrs

-  Males > females

-  Saphenous vein common source

 

Causes

-  Virchows Triad

-  Vascular stasis/turbulence

-  Endothelial injury

-  Hypercoaguability

-  Inactivity (plane or car trips) >4hrs in last 4/52

-  Immobilisation >3/7

-  Factor V Leiden 30%

-  Cancer

-  OCP

-  Post op 4/52

-  Effects up to 30% pts post op

-  Trauma, burns

-  Pregnancy

 

Associated S/S

-  65% below knee are asymptomatic

-  Unilateral ankle swelling

-  Superficial thrombophlebitis

-  Tenderness along course 75% pts

-  Pain at site 50% pts

-  Homans Sign

-   Pain on forced dorsiflexion

-   Not sensitive or specific

-   50% pts dont have DVT

-  Erythema, warmth & swelling

-  >3cm difference between calf diameters

-  Peripheral pitting oedema

-  PE

 

Ix

-  D-Dmimer

-  Doppler US of limb

-  Need to visualise pelvic veins if possible as most common site in pregnancy

-  Compression test

-  +/- Venogram

-  Gold standard but invasive

-  Not commonly done

-  Thrombophillic Screen

-  Pregnancy

-  Doppler US of limb

-  If positive then treat

-  If negative consider imaging of pelvic & iliac veins

-   If positive then treat

-   If negative then ongoing R/V & repeat imaging in symptoms persist

 

Mx

-  Warfarin

-  Enoxaparin cover whilst INR subtherapeutic

-  Target INR 2-3

-  Duration

-   3/12 if transient risk factors

-   6/12 if permanent risk factors

-  Enoxaparin

-  To cover until INR  2-3

-  Dose

-  1mg/kg S/C BD

-  OR 1.5mg/kg S/C Daily

-  If ARF, CRF 1mg/kg S/C Daily

-  Can use actual body weight rather than IBW

-  Normal dose if pregnant, BD dosing preferred

-  Check Anti-Xa levels if pregnant, obese or ARF, CRF

-  Asymptomatic with isolated calf vein DVT repeat US 10-14 days

-  Recurrent DVTs: IVC filter

-  DVT Prophylaxis

-  See also VTE in pregnancy

-  Pregnancy

-  See VTE in pregnancy

-  See PE (Mx in Pregnancy)

-  Requires 6/12 Rx or until 6/52 post partum (whichever longer)

-  Enoxaparin is anticoagulant of choice

-  Dose 1mg/kg (pre-pregnancy weight, up to max 100mg) BD

-  Due to physiological changes in pregnancy BD > Daily

-  Labour & Delivery

-  Generally induced close to term to allow control of anticoagulation in relation to labour

-  Cease 24-36hrs prior

-  May use Heparin infusion if really necessary

 

 

 

References

 

RCOG Greentop Guideliens No. 37b: The Acute Management of Thrombosis & Embolism During Pregnancy & the Puerperium, 2010

ANZJOG, Recommendations for the diagnosis & treatment of DVT & PE in pregnancy & the post partum period, 2012, 52: 14-22