Deep Vein Thrombosis

Aka: Deep Vein Thrombosis, Venous Thromboembolism, DVT, VTE, Thromboembolism

1. See Also
   1. Pulmonary Embolism
   2. DVT Prevention
   3. Deep Vein Thrombosis in Pregnancy
   4. Upper Extremity DVT
2. Epidemiology
   1. Deep Vein Thrombosis (DVT) represents 66% of Venous Thromboembolism (VTE)
      1. Pulmonary Embolism (PE) represents the remaining 33% of VTE
      2. Pulmonary Embolism accompanies proximal DVT in 40% of cases
      3. Deep Vein Thrombosis is identified in 70% of those with Pulmonary Embolism
   2. Venous Thromboembolism
      1. General population: 0.1% (100 per 100,000 person years)
         1. Effects 300,000 to 600,000 patients per year in U.S.
      2. Elderly: 1%
      3. Hospitalized patients: 15%
      4. VTE annual mortality in U.S.: estimated at 60,000 to 100,000 per year
3. Risk Factors
   1. See Deep Vein Thrombosis Risk Factors (includes Recurrent Thromboembolism Risks)
   2. See Thrombophilia
4. Signs
   1. Clinical exam is unreliable for DVT
   2. Homans' Sign (no predictive value)
      1. Homans' Sign: Relaxed foot abnormally plantar flexed
      2. Pseudo-Homans': Pain on passive dorsiflexion of foot
   3. Other unreliable signs
      1. Tenderness
      2. Distal extremity edema
      3. Palpable cord
5. Differential Diagnosis
   1. See Leg Edema
   2. Extremity Trauma
   3. Cellulitis
   4. Peripheral Arterial Disease
   5. Baker's Cyst (Pseudo-thrombosis)
   6. Superficial Thrombophlebitis
6. Diagnosis
   1. Precautions
      1. See DVT in Pregnancy
      2. Exercise caution in pregnancy
         1. Pregnancy is higher risk of pelvic DVT (which is higher risk of PE and more difficult to detect)
   2. Step 1: Assess DVT Probability
      1. See Wells Clinical Prediction Rule for DVT
      2. If moderate to high probability, goto step 3
   3. Step 2: Low Probability for DVT
      1. Obtain D-Dimer
      2. Negative D-Dimer: Excludes DVT in a low probability patient
         1. However, D-Dimer Test Sensitivity is 95%, and will miss 5% of DVTs
      3. Positive D-Dimer: Lower Extremity DopplerUltrasound
         1. Negative Ultrasound
            1. Excludes DVT
         2. Positive Ultrasound
            1. Treat as DVT
   4. Step 3: Moderate to high Probability for DVT
      1. Obtain Lower Extremity DopplerUltrasound (Test Sensitivity approaches 95%)
      2. Negative Compression Ultrasound: Obtain D-Dimer
         1. Negative D-Dimer
            1. Excludes DVT
         2. Positive D-Dimer
            1. Repeat Compression Ultrasound in one week or venography
      3. Positive Compression Ultrasound
         1. Treat as DVT
   5. References
      1. Bockenstedt (2003) N Engl J Med 349:1203-4 [PubMed]
7. Associated Conditions
   1. See Thrombophilia
   2. Idiopathic DVT associated with undiagnosed malignancy
8. Evaluation: Unprovoked Venous Thromboembolism
   1. Thrombophilia
      1. See Thrombophilia for testing indications
      2. Consider directed screening in unprovoked VTE when diagnosis impacts management
   2. Malignancy
      1. Associated with a higher VTE recurrence rate (esp. brain, myeloproliferative, ovarian, lung and non-rectal GI cancer)
      2. Present in 20% of patients with VTE
         1. Relative Risk of malignancy diagnosis in 2 years: 3.0
            1. Oudega (2006) Brit J Gen Pract 56:693-6 [PubMed]
         2. Prevalence of occult malignancy in unprovoked VTE: 3.9%
            1. Carrier (2015) N Engl J Med 373(8): 697-704 [PubMed]
      3. Perform age and gender appropriate routine malignancy screening
         1. No other occult malignancy testing recommended (unless dictated by signs and symptoms)
         2. Atypical location (e.g. splenic or cerebral vein) may warrant additional testing
         3. Recurrence despite Anticoagulation, Family History and weight loss may also prompt evaluation
9. Management: General
   1. See DVT in Pregnancy
   2. See Pulmonary Embolism Management
      1. Anticoagulation protocols are the same for DVT and PE
   3. Consider Thrombophilia work-up
      1. See Thrombophilia
      2. Reserve blood for tests prior to Anticoagulation
   4. Anticoagulation Protocol
      1. Anticoagulation in Thromboembolism
   5. Disposition
      1. Hospitalization and Heparin for high risk patients
      2. Consider home management with LMWH (see below)
   6. Local measures
      1. Early ambulation
         1. Replaces prior recommendations to minimize activity for first few days
      2. Elevate affected limb to reduce swelling
      3. Apply heat to affected limb
      4. Graded elastic Compression Stockings (20-30 mmHg)
         1. Reduce risk of postphlebitic syndrome (postthrombotic syndrome)
         2. Kolbach (2004) Cochrane Database Syst Rev (1): CD004174 [PubMed]
   7. Superficial Venous ThrombosisAnticoagulation indications
      1. See Superficial Venous Thrombosis
      2. Proximal superficial clot (upper thigh) especially within 5 cm of deep system
      3. Clot >7 cm long in leg
      4. Lack of improvement after 1 week
      5. Hypercoagulable state
10. Management: Distal DVT (Calf-vein DVT)
    1. Option 1: Anticoagulation (standard strategy since 2001)
       1. Anticoagulation recommended for 6 to 12 weeks
          1. Initiate with LMWH and then to oral Warfarin (or other Anticoagulant - see above)
       2. Justification (based on risk of untreated calf DVT complications)
          1. Risk of propogation to proximal DVT is 5-20% (NNT 16)
          2. Recurs in 30% of untreated patients
          3. Post-thrombotic syndrome occurs in 20% if untreated
          4. Pinede (2001) Circulation 103:2453-60 [PubMed]
          5. Utter (2016) JAMA Surg 151(9): e161770 +PMID:27437827 [PubMed]
    2. Option 2: 2015 Chest Guidelines recommend serial Ultrasound instead of Anticoagulation
       1. Assumes lower risk patient
          1. Asymptomatic
          2. No cancer history or other underlying Coagulopathy
          3. DVT not unprovoked and not recurrent
       2. Preferred strategy if Anticoagulation contraindicated or increased bleeding risk
       3. Safe even in symptomatic patients, with similar outcomes to Anticoagulation, but without the 4% bleeding risk
          1. Righini (2016) Lancet Hematol 3(12): e556-62 +PMID: 27836513 [PubMed]
       4. Repeat Doppler Ultrasound twice weekly for 2 weeks
       5. Monitor for extension of distal DVT to proximal DVT
       6. Kearon (2016) Chest 149(2): 315-52 +PMID:26867832 [PubMed]
11. Management: Anticoagulation
    1. See Anticoagulation in Thromboembolism
12. Management: Home Deep Vein Thrombosis Protocol
    1. Criteria for home management
       1. No massive Deep Vein Thrombosis
          1. No entire Leg Swelling, acrocyanosis or ischemia
          2. No DVT extension into iliofemoral vein or IVC
       2. No symptomatic Pulmonary Embolism
          1. Oxygen Saturation >95% on room air
       3. No significant bleeding risks on Anticoagulants
          1. Active bleeding or bleeding in last 4 weeks
          2. Recent surgery or Trauma
          3. Platelet Count <70, INR >1.4 or PTT >40 sec
          4. Metastatic disease involving liver or brain
       4. No significant comorbidities
          1. No severe liver or Kidney disease
          2. Impaired cognition or mobility
          3. Pain requiring parenteral Narcotics
       5. References
          1. Douketis (2005) Can Fam Physician 51:217-23 [PubMed]
    2. Efficacy
       1. Safe and effective management of proximal DVT
       2. Spyropoulos (2002) Chest 122:108-14 [PubMed]
    3. Review Contraindications
       1. Use only in otherwise low risk patients
       2. See Low Molecular Weight Heparin for contraindication
    4. Patient Education
       1. Demonstrate self-administered Subcutaneous Injections
       2. Review sterile technique
       3. Review risks of bleeding and infection
       4. Emphasize precautions against Trauma
    5. Consider home health referral
    6. Anticoagulation
       1. See Anticoagulation in Thromboembolism
13. Management: Intervention Radiology directed Thrombolysis (with benefit)
    1. Ileofemoral DVT (typically within last 14 days)
       1. High risk of comorbidity
          1. Post-thrombotic syndrome: >50%
          2. Venous Claudication at 5 years in nearly half of patients
       2. Efficacy data (some studies question longterm benefit)
          1. Normal vein after Catheter Thrombolysis: 45% (contrast with 0% after Heparin alone)
          2. Decreases risk of long term Venous Insufficiency, post-phlebitic syndrome, stasis ulcers
          3. Best outcome if performed early (within 2 weeks)
          4. Poor efficacy if prior Deep Vein Thrombosis
       3. References
          1. (2009) J Thromb Haemost 7:1268-75 [PubMed]
    2. Other indications
       1. Massive proximal extremity DVT with severe symptoms or Limb Threatening Ischemia
14. Complications
    1. Pulmonary Embolism (PE)
       1. PE is an increased risk in the first 2 weeks after DVT diagnosis and Anticoagulation start
    2. Post-thrombotic syndrome (postphlebitic syndrome)
       1. Reduced with below knee graded Compression Stockings
          1. Prandoni (2004) Ann Intern Med 141:249-56 [PubMed]
       2. Encourage 30 minute walk per day
          1. Kahn (2011) CMAJ 183(1):37-44 +PMID:21098066 [PubMed]
    3. Breakthrough Venous Thromboembolism (2 to 3% of VTE patients on Anticoagulation for 6 months)
       1. Considered Breakthrough VTE if occurs at least 2 weeks after consistent Anticoagulation initiated
    4. Phlegmasia (Milk Leg)
       1. Phlegmasia Alba Dolens
          1. Painful, white leg following ileo-femoral deep vein obstruction
       2. Phegmasia Cerulea Dolens
          1. Painful, cyanotic, edematous leg following ileo-femoral deep and superficial vein obstruction
          2. Venous Gangrene (capillary obstruction) results if not promptly managed
15. Prognosis
    1. Mortality: 6% within 1 month of DVT diagnosis
    2. Recurrence when not on Anticoagulation
       1. See Thromboembolism Risk Factors
       2. Provoked VTE with transient risk factors: 3.3% recurrence rate in first year
       3. Unprovoked VTE: 10.3% recurrence rate in first year (30% in first 10 years)
       4. Proximal DVT has a 4 fold higher risk of recurrence than distal DVT
       5. Central Pulmonary Embolism has higher risk of recurrence than peripheral PE
       6. Elevated D-Dimer 3 weeks after stopping Anticoagulation is associated with higher risk of VTE recurrence
          1. Eichinger (2003) JAMA 290(8): 1071-4 [PubMed]
16. Prevention
    1. See DVT Prevention
    2. See DVT Prophylaxis
    3. See DVT Prevention in Travelers
17. Resources
    1. CDC: Venous Thromboembolism
       1. https://www.cdc.gov/ncbddd/dvt/data.html
18. References
    1. Feied in Marx (2002) Rosen's Emergency Med, p. 1210-33
    2. AbuRahma (2001) Ann Surg 233(6):752 [PubMed]
    3. Forster (2001) Chest 119(2):572-9 [PubMed]
    4. Hull (2000) Arch Intern Med 160:229-36 [PubMed]
    5. Hyers (2001) Chest 119:176S-93S [PubMed]
    6. Lensing (1999) Lancet 253:479-85 [PubMed]
    7. Merli (2001) Ann Intern Med 134:191-202 [PubMed]
    8. Mount (2022) Am Fam Physician 105(4): 377-85 [PubMed]
    9. Ramzi (2004) Am Fam Physician 69:2841-8 [PubMed]
    10. Wells (2001) Thromb Haemost 86(1):499-508 [PubMed]
    11. Wilbur (2012) Am Fam Physician 86(10):913-9 [PubMed]