In patients complaining of leg pain and/or swelling, evaluate the likelihood of deep venous thrombosis (DVT) as investigation and treatment should differ according to the risk.
In patients with high probability for thrombotic disease (e.g., extensive leg clot, suspected pulmonary embolism) start anticoagulant therapy if tests will be delayed.
Identify patients likely to benefit from DVT prophylaxis.
Utilize investigations for DVT allowing for their limitations (e.g., Ultrasound and D-dimer).
In patients with established DVT use oral anticoagulation appropriately, (e.g., start promptly, watch for drug interactions, monitor lab values and adjust dose when appropriate, stop warfarin when appropriate,provide patient teaching).
Consider the possibility of an underlying coagulopathy in patients with DVT, especially when unexpected.
Use compression stockings in appropriate patients, to prevent and treat post-phlebitic syndrome.
Diagnosis
Pre-test probability (clinical suspicion)
Risk: Virchow's Triad = Stasis, endothelial injury, hypercoagulable state
Acquired:
Prior thromboembolism
Recent major surgery
Trauma
Immobilization
Antiphospholipid antibodies
Malignancy
Pregnancy
Oral contraceptives
Myeloproliferative disorders
Hereditary:
Factor V Leiden
Prothrombin gene mutations
Protein S or C deficiency
Antithrombin deficiency
Wells Score for DVT Diagnosis
+1 point for each of the following
Paralysis, paresis or recent orthopedic casting of lower extremity
Bedridden >3 days recently or major surgery within 4 weeks
Localized tenderness of the deep veins
Swelling of entire leg
Calf swelling 3 cm greater than other leg (measured 10 cm below the tibial tuberosity)
Pitting edema greater in the symptomatic leg
Non-varicose collateral superficial veins
Active cancer or cancer treated within 6 months
Previously documented DVT
-2 points for alternative diagnosis at least as likely as DVT (Baker's cyst, cellulitis, muscle damage, superficial vein thrombosis, post-thrombotic syndrome, inguinal lymphadenopathy, extrinsic venous compression)
Score <2 = 6% DVT, ≥2 = 28% DVT
Upper Extremity DVT
Risk: Central venous catheter, recent pacemaker, malignancy
Proximal Venous Compression Ultrasound (pCUS)
Note distal thrombosis may extend proximally in 20% (repeat in 7 days if suspect DVT)
Recurrent DVT can be difficult to diagnose due to residual compression abnormalities from previous DVT - must compare CUS results to previous study for new findings
D-Dimer
Treatment
Patients with moderate-high suspicion of DVT (unless high risk of bleed) should start anticoagulation before diagnosis
Anticoagulate for initial 3 months, consider indefinite in unprovoked and cancer (and low risk bleeding):
LMWH or IV heparin (5000 units bolus then 20 units/kg/hr target aPTT 2-3x control aPTT) overlap with warfarin for minimum 5 days and INR >2 for minimum 2 days
Consider Warfarin in valvular A Fib, CrCl<30, Antiphospholipid syndrome, Weight >120kg, Gastric bypass, Liver failure
DOAC
Apixaban 10mg PO BID x 1 week, then 5mg PO BID (can decrease to 2.5mg PO BID after 6 months)
Rivaroxaban 15mg PO BID x 3 weeks then 20mg PO daily (can decrease to 10mg PO daily after 6 months)
Note: Dabigatran and Edoxaban require 5-10 day initial treatment bridge with LMWH
Subcutaneous LMWH (eg. Dalteparin 100 U/kg SC daily or Enoxaparin 1.5mg/kg SC daily) or IV heparin x 5-10 days, then dabigatran 150mg PO BID
LMWH x 1 month then DOAC or warfarin
LMWH preferred in Cancer and in Pregnancy, advantages include fixed/simple-dosing and lower HIT
There is some evidence that apixaban can be used as an alternative for patient with cancer who do not want injections (but avoid in upper GI malignancy due to increased rate of bleeding)
Only consider Aspirin in those who are adverse to long-term anticoagulation (32% reduction of recurrent VTE vs 82% when on oral anticoagulants)
Isolated distal DVT anticoagulation only if symptomatic and risk factors for extension (severe symptoms, >5cm in length, multiple deep veins, close to popliteal veins, no reversible risk factor, previous VTE, in-patient, positive D-dimer) or progression on imaging
Superficial vein thrombosis can be treated with topical/oral NSAIDs for symptoms, if >5cm consider low-intermediate dose LMWH
Urgent surgical intervention for phlegmasia cerulea dolens (extensive thrombosis which can cause irreversible ischemia, necrosis, gangrene)
Prophylaxis
Hip/knee arthroplasty, hip fracture = 14-35 days
Major orthopedic trauma, Complicated Spine Surgery, Isolated below-knee fracture, L/E amputation, bedrest = until discharge
Post-thrombotic syndrome (PTS)
Signs of chronic venous insufficiency (usually 6 months) after a DVT (extremity pain, heaviness, cramps, paresthesias, pruritus, venous dilation, edema, pigmentation, skin changes, and venous ulcers)
Occurs in 50% of patients within one year of thrombosis, 5-10% severe PTS
Risk:
Elderly, obesity
Smoking
Primary venous insufficiency, varicose veins
Proximal DVT, residual thrombus after treatment, recurrent DVT, inadequate anticoagulation
Treatment (similar to chronic venous disease)
Smoking cessation, weight loss if obesity
Elevation
Exercise training
Compression stockings/bandages (30-40mmHg) or Compression device
Prevention
If at risk of PTS, consider compression stockings (start within two weeks of diagnosis, after anticoagulation started, and continue for two years)
Liu D et al; Interdisciplinary Expert Panel on Iliofemoral Deep Vein Thrombosis (InterEPID). Diagnosis and management of iliofemoral deep vein thrombosis: clinical practice guideline. CMAJ. 2015 Nov 17;187(17):1288-96. doi: 10.1503/cmaj.141614. Epub 2015 Sep 28. http://www.cmaj.ca/content/187/17/1288