Confirmed leg DVT in an adult
Deep vein thrombosis on compression ultrasound. Adults only; not for pregnancy or children.
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Internal MedicineManagement
Deep Vein Thrombosis Management (ASH 2020)
Deep Vein Thrombosis Management (ASH 2020): Confirmed leg DVT in an adult → Red flags first: limb threat, possible PE, pregnancy → Is the DVT proximal (...
Pathway Overview
21 steps
Algorithm Steps
21 total
01Start 02Warning Red flags first: limb threat, possible PE, pregnancy
Check these before routine care. Children: use a paediatric pathway.
- Limb-threatening DVT (phlegmasia: massive swelling, cyanosis, severe pain, poor perfusion): admit, start anticoagulation, urgent vascular review
- Chest pain, breathlessness, low SpO2, syncope or tachycardia: assess for PE now; do not treat as simple DVT at home
- Pregnant or breastfeeding: use LMWH, not a DOAC; seek obstetric medicine advice
03Decision Is the DVT proximal (popliteal vein or above)?
Proximal: popliteal, femoral or iliac vein. Distal: calf veins only (tibial, peroneal, gastrocnemius, soleal).
- If Yes
- Proximal
04Action Proximal DVT: anticoagulate unless contraindicated
Treat for at least 3 months. Higher risk of PE and recurrence than distal DVT.
- Thrombolysis is not routine. Consider (specialist decision) only for limb-threatening DVT or selected younger patients with iliofemoral DVT and low bleeding risk; catheter-directed preferred
- Compression stockings are not routine; they may help pain and swelling
05Decision Safe to start anticoagulation now?
No if: active bleeding, recent intracranial bleeding, recent brain, spinal or eye surgery, or severe thrombocytopenia or coagulopathy.
- If Yes
- Safe
06Warning High bleeding risk (not a contraindication): treat, review early
Risk factors: prior bleeding, peptic ulcer, surgery in the last 14 days, severe kidney disease, active cancer, low platelets. Treat reversible causes.
- Recent ischaemic stroke, stroke thrombolysis or intracranial lesion: agree the start time with the stroke or neurosurgery team
- Stop aspirin and NSAIDs unless essential. Recent acute coronary event or stent: ask cardiology
- Low-risk distal DVT: serial ultrasound is an option instead
07Warning Before a DOAC: check APS, kidney and liver function, interacting drugs
Mechanical heart valve: use warfarin, not a DOAC. Also seek haematology advice if weight is 150 kg or more, or after bariatric surgery.
- Antiphospholipid syndrome (especially triple positive): do not use a DOAC; use warfarin, INR 2.0 to 3.0
- Kidney or liver: seek advice if CrCl below 30 mL/min, Child-Pugh B or C, or liver disease with coagulopathy. Contraindicated: apixaban CrCl <25 or Child-Pugh C; dabigatran CrCl <30; rivaroxaban CrCl <15 or Child-Pugh B or C
- Strong CYP3A4 and P-gp inhibitors or inducers (azole antifungals, HIV protease inhibitors, rifampicin, carbamazepine, phenytoin, St John's wort): avoid DOAC or seek advice
08Action Start anticoagulation: DOAC preferred over warfarin
Start at once if no contraindication. No DOAC is preferred over another; choose by lead-in need, dosing, kidney function, interactions and cost. Doses for adults.
- Apixaban: 10 mg orally twice daily for 7 days, then 5 mg twice daily
- Rivaroxaban: 15 mg orally twice daily with food for 21 days, then 20 mg once daily with food
- Dabigatran: parenteral anticoagulant (LMWH) for at least 5 days first, then 150 mg orally twice daily; 110 mg twice daily if 75 years or older; consider 110 mg twice daily if CrCl 30-50 mL/min or high bleeding risk
- Edoxaban (not registered in Australia): parenteral anticoagulant for 5 to 10 days first, then 60 mg orally once daily (30 mg if CrCl 15-50 mL/min, weight 60 kg or less, or some P-gp inhibitors)
- Warfarin: start with LMWH; overlap at least 5 days and until INR is 2 or more on 2 days in a row; target INR 2.0 to 3.0
- LMWH (enoxaparin, dalteparin): dose by weight and kidney function; see product information. Prior HIT: avoid heparins
09Action Setting: treat at home unless hospital care is needed
Home treatment is suggested for uncomplicated DVT. Admit if: limb-threatening DVT, suspected PE, high bleeding risk, IV pain relief, another reason for admission, poor home support, cannot get the medicine, or poor adherence.
- Home: give the first dose, a supply of medicine, bleeding advice and a follow-up plan
10Decision After 3 to 6 months of primary treatment: stop or continue?
Base the decision on the cause of the DVT, bleeding risk and patient preference.
- Transient risk factor
11Outcome Transient risk factor: stop after primary treatment
Major surgery or trauma: stop at 3 months (distal DVT: 6 weeks to 3 months). Non-surgical transient factor: 3 to 6 months, then weigh extended treatment. Prior unprovoked VTE: continue indefinitely.
- Unprovoked
12Action Unprovoked DVT: continue indefinitely if bleeding risk allows
Most patients with unprovoked proximal DVT continue indefinitely. Unprovoked distal DVT: usually stop at 3 months. Decide with the patient.
- High bleeding risk: stop after 3 to 6 months
- Recurrent unprovoked VTE: indefinite treatment
- Consider antiphospholipid antibody tests; anticoagulants affect lupus anticoagulant results, so seek advice
13Action Long-term anticoagulation: review at least once a year
Check bleeding, kidney and liver function, weight, interacting drugs and adherence.
- After 6 months, a lower dose is an option (not studied in active cancer): apixaban 2.5 mg twice daily or rivaroxaban 10 mg once daily
- Use an anticoagulant, not aspirin, for secondary prevention
- Warfarin: keep INR 2.0 to 3.0
- New VTE on therapeutic warfarin: switch to LMWH and seek haematology advice
- Chronic risk factor
14Action Chronic risk factor (not cancer): continue indefinitely
For example inflammatory bowel disease, other autoimmune disease or chronic immobility. Continue after primary treatment unless bleeding risk is high.
- Path rejoins step 13Shared downstream outcome
- Active cancer
15Action Active cancer: LMWH or factor Xa inhibitor for at least 6 months
Apixaban, rivaroxaban, edoxaban (not in Australia) or LMWH. Continue beyond 6 months while the cancer is active or treated.
- GI or genitourinary cancer, or high mucosal bleeding risk: caution with factor Xa inhibitors; LMWH is often preferred
- Check interactions with cancer drugs
- Involve oncology or haematology
- Path rejoins step 13Shared downstream outcome
If No- Contraindicated
16Warning Cannot anticoagulate, proximal DVT: consider retrievable IVC filter
Start anticoagulation as soon as the contraindication resolves, then remove the filter.
- Do not insert a filter if the patient can take anticoagulation
- Distal DVT: repeat ultrasound in place of a filter
- Set a retrieval plan at insertion
- Path rejoins step 08Shared downstream outcome
If No- Distal
17Decision Distal DVT: severe symptoms or risk of extension?
Risk of extension: positive D-dimer, clot longer than 5 cm, wider than 7 mm or in several veins, clot near the popliteal vein, no reversible cause, active cancer, prior VTE, inpatient.
- If Yes
- Symptoms or risk factors
18Action Distal DVT with symptoms or risk factors: anticoagulate
Use the same drugs as for proximal DVT.
- Provoked by a major factor that has resolved: treat 6 weeks to 3 months
- Unprovoked or ongoing risk factor (not cancer): treat 3 months
- Active cancer: follow the cancer step; continue beyond 6 months while the cancer is active
- Path rejoins step 05Shared downstream outcome
If No- Low risk
19Action Low-risk distal DVT: anticoagulate, or repeat ultrasound
Mild symptoms and no risk factors for extension. Serial ultrasound is reasonable, especially if bleeding risk is high. Decide with the patient.
- Serial ultrasound: 2 scans over 2 weeks (for example at 1 and 2 weeks)
- Worse or new symptoms: rescan sooner
- Extends into proximal veins: treat as proximal DVT
- Extends within calf veins: anticoagulate
20Decision Anticoagulation chosen, or clot extends on repeat scan?
Yes: start anticoagulation. No: no anticoagulation.
- If Yes
- Treat
- Path rejoins step 05Shared downstream outcome
If No- No extension
21Outcome No extension over 2 weeks: no anticoagulation
Stop surveillance. Return at once if leg symptoms worsen or chest symptoms start.
Guideline Source
ASH 2020 Guidelines for Management of Venous Thromboembolism: Treatment of DVT and PE
Clinical Safety Information
Clinical Decision Support — Not a Substitute for Clinical Judgment
Individual patient factors may require deviation from these recommendations.
Known Limitations
- Adults with leg DVT only. Not for pregnancy, children, or upper-limb, splanchnic or cerebral vein thrombosis.
- Does not select patients for thrombolysis, thrombectomy or stenting; seek vascular or interventional advice.
- ASH 2020 does not address isolated distal DVT; that advice follows THANZ 2019 and CHEST.
- Cancer-associated VTE needs oncology or haematology input.
- Check local availability and subsidy of each anticoagulant.
Contraindicated Populations
pregnancybreastfeedingchildren
Applicable Regions
USEUAU
AU: Consistent with THANZ 2019 VTE guideline (Tran et al., MJA 2019). Doses match the Australian product information for apixaban, rivaroxaban and dabigatran. Edoxaban has no Australian product information (TGA eBS search, Sep 2026).
EU: NICE NG158 and ESVS 2021 give similar advice.
US: Based on ASH 2020 VTE treatment guideline.
Version 2Next review: 2027-09-30
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Related Resources
Frequently Asked Questions
What is the Deep Vein Thrombosis Management (ASH 2020)?
The Deep Vein Thrombosis Management (ASH 2020) is a management clinical algorithm for Internal Medicine. It provides a structured decision tree to guide clinical decision-making, based on ASH 2020 Guidelines for Management of Venous Thromboembolism: Treatment of DVT and PE.
What guideline is the Deep Vein Thrombosis Management (ASH 2020) based on?
This algorithm is based on ASH 2020 Guidelines for Management of Venous Thromboembolism: Treatment of DVT and PE (DOI: 10.1182/bloodadvances.2020001830).
What are the limitations of the Deep Vein Thrombosis Management (ASH 2020)?
Known limitations include: Adults with leg DVT only. Not for pregnancy, children, or upper-limb, splanchnic or cerebral vein thrombosis.; Does not select patients for thrombolysis, thrombectomy or stenting; seek vascular or interventional advice.; ASH 2020 does not address isolated distal DVT; that advice follows THANZ 2019 and CHEST.; Cancer-associated VTE needs oncology or haematology input.; Check local availability and subsidy of each anticoagulant.. Individual patient factors may require deviation from these recommendations.
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