Deep vein thrombosis: workup and management
Suspected DVT: estimate pre-test probability with the Wells DVT score, use D-dimer to exclude DVT when probability is low, and compression ultrasound otherwise. Most patients can be treated as outpatients with a DOAC. Always ask about PE symptoms.
Working diagnosis
Adult · US guidelines
Draft · awaiting physician review
01Orient
What's new in the evidence
- 2026 AHA/ACC PE guideline (also applies to VTE treatment): DOAC preferred over warfarin; LMWH preferred over unfractionated heparin
- Extended-phase reduced-dose DOAC (apixaban 2.5 mg twice daily or rivaroxaban 10 mg daily) after 6 months is an option for unprovoked or persistent-risk VTE
- ATTRACT (2017): routine catheter-directed thrombolysis does not prevent post-thrombotic syndrome
Differential diagnoses
- Proximal or distal DVT
- Pulmonary embolism coexisting (can't miss)
- Phlegmasia cerulea dolens (can't miss: limb-threatening)
- Cellulitis, ruptured Baker's cyst, muscle injury
- Superficial thrombophlebitis
- Lymphedema, venous insufficiency, drug-induced edema
02Assess
Risk scores and decision tools
- Wells DVT score
- D-dimer (age-adjusted over 50) when DVT is unlikely
- HAS-BLED or VTE-BLEED for extended-phase bleeding risk
Key history questions
- Onset and side of swelling and pain
- Recent surgery, immobility, travel, trauma, cast
- Active cancer, pregnancy or postpartum, estrogen therapy
- Prior VTE, family history
- Dyspnea, chest pain, syncope (PE)
- Bleeding risks
Examination findings
- Calf circumference difference >3 cm, pitting edema, tenderness along deep veins
- Dilated superficial collateral veins
- Limb color, pulses (phlegmasia)
- Signs of PE
03Investigate
Initial investigations
- Wells DVT score
- D-dimer if DVT unlikely; compression ultrasound if likely or D-dimer positive
- CBC, creatinine, LFTs, coagulation before anticoagulation
Advanced investigations
- Repeat ultrasound in 1 week if initial proximal ultrasound is negative and suspicion persists
- Age-appropriate cancer screening; no routine thrombophilia testing in the acute phase
04Treat
Immediate management
- Phlegmasia: urgent vascular consult for catheter-directed therapy
- Start anticoagulation while awaiting imaging if suspicion is high and bleeding risk low
First-line treatment
- Apixaban 10 mg twice daily for 7 days, then 5 mg twice daily, or rivaroxaban 15 mg twice daily for 21 days, then 20 mg daily
- Treat at least 3 months; provoked by surgery: stop at 3 months
- Unprovoked or persistent risk: consider extended therapy
Second-line treatment
- Cancer-associated: DOAC (apixaban preferred if GI or GU lesion) or LMWH
- Isolated distal DVT with low risk: serial ultrasound for 2 weeks is an alternative to anticoagulation
- IVC filter only if anticoagulation is contraindicated
Specialist referrals
- Vascular surgery for phlegmasia or extensive iliofemoral DVT
- Hematology for recurrent or unusual-site thrombosis
05Disposition
Admission criteria
- Massive iliofemoral DVT or phlegmasia
- Concurrent PE needing admission, high bleeding risk
- Unable to obtain or manage anticoagulation
Safe discharge criteria
- Stable, no PE features, low bleeding risk
- DOAC supplied and affordable; follow-up arranged
Follow-up timing
- Review at 1–2 weeks and at 3 months to decide duration
Patient instructions
- Walk as tolerated; compression stockings for symptom relief
- Return for chest pain, breathlessness or bleeding
Monitoring
- Renal function and CBC on anticoagulation
Clinical pearls and pitfalls
- Routine catheter-directed thrombolysis does not prevent post-thrombotic syndrome in most patients
- Upper-extremity DVT is usually line- or device-related
RefGuidelines and landmark evidence
- GuidelineCHEST – Antithrombotic Therapy for VTE Disease: Second Update (2021)PubMed
- GuidelineASH – Guidelines for Management of VTE: Treatment of DVT and PE (2020)PubMed
- TrialD-dimer with Wells score to rule out DVT (Wells et al., 2003)PubMed
- TrialATTRACT: catheter-directed thrombolysis for DVT (2017)PubMed
For education only. Typical adult starting points; confirm doses against renal function, allergies, interactions and your institution's protocols. Not a substitute for clinical judgment or senior review.