DVT

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Definition

·      Proximal DVT: Clot formation in the popliteal vein or higher.

·      Distal DVT: Isolated clot in the calf veins (anterior/posterior tibial and peroneal veins)

 

Signs and Symptoms

·      Cramping or calf fullness

·      Lower extremity: unilateral leg swelling, edema, redness (can resemble cellulitis) and pain

·      Upper extremity: arm swelling, finger swelling (ill-fitting rings)

 

Pre-test Probability

 Wells Score

Dr. Wells – “The model should be applied only after a history and physical suggests that venous thromboembolism is a diagnostic possibility. it should not be applied to all patients with chest pain or dyspnea or to all patients with leg pain or swelling. This is the most common mistake made.”

Ultrasound

·      Diagnostic method of choice

·      Multiple Systems: 3-point system (common, superficial femoral veins, and popliteal veins) and whole leg

·      Low pretest probability

o   A negative 3-point US effectively rules out DVT

o   A negative whole leg US effectively rules out DVT

 

·      Moderate to High pretest probability

o   Ultrasound does not rule out DVT, must add D-dimer or repeat ultrasound in 1 week.

 

CT Venogram

·       Can be added on to CTPA that’s being performed for PE.

·       Identifies DVT in the absence of PE in up to 2% of patients

 

MRI

·       Limited utility due to cost, availability, and no superiority to ultrasound

·       Useful for evaluation of pelvic veins and vena cava

Management 

  • Proximal DVT without history of cancer

    • Oral anticoagulant alone (dabigatran, rivaroxaban, apixaban or edoxaban (NOAC)) preferred over a vitamin K antagonist (VKA) (Grade 2B recommendation)

    • VKA preferred to low-molecular weight heparin (LMWH) (Grade 2C recommendation)

    • Duration of treatment: 3 months for 1st clot (Grade 1B recommendation)

  • Proximal DVT with cancer

    • LMWH preferred to VKA therapy, dabigatran, rivaroxaban, apixaban or edoxaban (Grade 2C recommendation)

    • Duration of treatment: 3 months for 1st clot (Grade 1B recommendation)

  • Distal DVT (isolated)

    • The significance of isolated distal DVTs is unknown.

    • It is unclear whether systemic anticoagulation is beneficial to the patient with these clots

    • Risk factors for extension

      • D-dimer is positive (particularly with larger elevations)

      • Extensive thrombosis (> 5 cm in length, multiple veins, > 7 mm diameter)

      • Proximity to proximal veins

      • No reversible provoking factor for the DVT

      • Active cancer

      • History of VTE

      • Admitted to the hospital

    • Absence of severe symptoms and no risk factors for extension

      • Serial imaging over 2 weeks preferred to anticoagulation (Grade 2C recommendation)

      • No established role for providing antiplatelet therapy (i.e. aspirin) alone in these cases but a reasonable intervention

    • Presence of severe symptoms or risk factors for extension

      • Anticoagulation preferred to serial imaging (Grade 2C recommendation)

      • Anticoagulation choices same as for proximal DVT (Grade 1B recommendation)

  • Superficial Thrombophlebitis

    • Saphenous vein clots above the knee can spread into deep venous system via the saphenous-femoral junction

    • Initial treatment with NSAIDs, warm compresses and compression stockings

    • Repeat US in 2-5 days and start anticoagulation if clot extending

  • Catheter-Directed Thrombolysis (CDT)

    • Does not show substantial benefits in most patients with proximal DVT and likely increases risk of major bleeding

    • Patients with iliofemoral DVT and a low risk of bleeding may benefit from CDT

Disposition

·       Discharge

Consider if all the following are present:

o   Ambulatory

o   Hemodynamically stable

o   Low risk of bleeding in patient

o   Absence of renal failure

o   Able to administer anticoagulation with appropriate monitoring

o   Able to arrange for 2-3 days follow-up

·       Admit

o   Ileofemoral DVT that is a candidate for thrombectomy (should have the following):

§  Acute iliofemoral DVT (symptom duration <21 days)

§  Low risk of bleeding

§  Good functional status and reasonable life expectancy

o   Phlegmasia Cerulea Dolens

§  DVT that causes phlegmasia cerulea dolens requires rapid action

§  Anticoagulate, place limb at a neutral level, and arrange for consultant-delivered catheter-directed thrombolysis.

§  Transfer if don’t have services or can’t be arranged within 6 hours, consider systemic fibrinolytics if there are no absolute contraindications.

§  One regimen is 50 to 100 milligrams of alteplase infused IV over 4 hours.

o   High risk of bleeding on anticoagulation

o   Significant comorbidities

o   Symptoms of concurrent PE

o   Recent (within 2 weeks) stroke or transient ischemic attack

o   Severe renal dysfunction (GFR < 30)

o   History of heparin sensitivity or HIT

o   Weight > 150kg

o   Upper extremity DVT

 

References

https://coreem.net/core/deep-venous-thrombosis-dvt/

https://journal.chestnet.org/article/S0012-3692(15)00335-9/fulltext

https://wikem.org/wiki/Deep_venous_thrombosis

Tintanillis Emergency Medicine Comprehensive Study Guide

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