Deep Vein Thrombosis

Overview

Deep vein thrombosis (DVT) is the formation of a blood clot in a vein deep under the skin 25-50% of surgical patients and many non-surgical patients. 65% of DVT are below the knee are symptomatic and rarely embolism to the lung. There are many causes of DVT.

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Pathophysiology

All comes down to Virchow’s Triad. Any change to Virchows triad increases the risk of VTE.

Hypercoagulability

• Malignancy
• Surgery
• Trauma
• Oral contraceptive pill
• Genetic
• Antiphosphlipid syndrome
• Hyper homocysteine level

Inherited Thombophilias

Factor 5 leiden mutation

Pro-thrombin gene mutation

Protein S deficiency

Protein C deficiency

Stasis

• Immobility, e.g. after surgery
• Pregnancy
• Obesity
• Heart failure
• Cast on the leg
• Extended travel in plane/vehicle

Endothelial injury

• Inflammation
• Previous thrombosis
• Atherosclerosis
• Fracture

Clinical Manifestation

Clinical Presention DVT usually affects the veins in the legs, notably the calf.

• Asymmetrical pain and/or tenderness
• Asymmetrical warmth/ erythema
• Asymmetrical swelling

Signs of Pulmonary embolism (complication of DVT)

• Breathlessness
• Chest pain
• Coughing
• Tachycardia
• Haemoptysis

Wells Criteria

MODIFIED WELL CRITERIA
Clinical features	Score
Active cancer	1
Paralysis, paresis, or recent cast immobilization of the lower extremities	1
Recently bedridden for ≥ 3 days, or major surgery within the previous 12 weeks requiring general or regional anesthesia	1
Localized tenderness along the distribution of the deep venous system	1
Entire leg swelling	1
Calf swelling at least 3 cm larger than that on the asymptomatic side	1
Pitting edema confined to the symptomatic leg	1
Collateral superficial veins (non-varicose)	1
Previously documented deep vein thrombosis	1
Alternative diagnosis at least as likely as deep vein thrombosis	2

Wells Scoring System – help tailor investigations

• Low probability: 0
• Moderate probability: 1-2
• High probability: 3-8

Diagnosis

• Cellulitis
• Thrombophlebitis
• Arthritis
• Asymmetric peripheral oedema secondary to heart failure, renal disease or liver disease
• Haematoma
• Lymphoedema
• Ruptured backers cyst
• Varicose veins

Diagnosis

• Duplex ultrasound
• Venography (phlebography) – Gold standard

Treatment

The aim of treatment is to prevent PE, reduce morbidity and prevent or minimise the risk of developing the postphlebitic syndrome

• Pain management – analgesia +/- opioids
• Anticoagulation
  • Low risk bleeding – Low molecular weight heparin (enoxaparin 1.5mg/kg SC daily)
  • Average risk bleeding – Unfractionated heparin

MANAGEMENT DURATION
Clinical situation	Duration
VTE provoked by transient major risk factor	3 months
Distal unprovoked DVT or PE	3 months
First unprovoked proximal DVT or PE	6 months
First unprovoked VTE plusActive malignancyMultiple thrombophiliasAntiphospholipid syndrome	Indefinite
Recurrent unprovoked VTE	Indefinite

Complications & Prognosis

Complications

• Acute
  • Pulmonary Embolism 

• Phlegmasia cerulea dolens (acute limb gangrene)
• Chronic
  • Post thrombotic syndrome
  • Chronic venous insufficiency

Prognosis

Prevention

• Identify patient at risk
• Prevent Dehydration
• Mechanical prophylaxis
  • Intermittent Pneumotic Compression
  • Calf compression stockings
• Encourage movement
• Exercise
• Quit smoking
• Medication – Warfarin to therapeutic dose INR 2-3 OR NOAC of choice
• IVC filter

Prevention in surgery

• High Risk – LMWH (40mg daily) + mechanical prophylaxis
  • Orthopaedic Surgery
  • Major trauma
  • Fracture
  • Major surgery >40yo
• Medium Risk – LMWH (20mg daily) + mechanical prophylaxis
• Low Risk – Consider LMWH + mechanical prophylaxis
  • All other surgery

References

1. Di Nisio M, van Es N, Büller HR. Deep vein thrombosis and pulmonary embolism. Lancet. 2016;388(10063):3060-3073.
2. Lim W, Le Gal G, Bates SM, Righini M, Haramati LB, Lang E, et al. American Society of Hematology 2018 guidelines for management of venous thromboembolism: diagnosis of venous thromboembolism. Blood Adv. 2018;2(22):3226-3256. doi:10.1182/bloodadvances.2018024828.
3. Wells PS, Anderson DR, Rodger M, Forgie M, Kearon C, Dreyer J, et al. Evaluation of D-dimer in the diagnosis of suspected deep-vein thrombosis. N Engl J Med. 2003;349(13):1227-1235. doi:10.1056/NEJMoa023153.
4. Ortel TL, Neumann I, Ageno W, Beyth R, Clark NP, Cuker A, et al. American Society of Hematology 2020 guidelines for management of venous thromboembolism: treatment of deep vein thrombosis and pulmonary embolism. Blood Adv. 2020;4(19):4693-4738. doi:10.1182/bloodadvances.2020001830.
5. Stevens SM, Woller SC, Kreuziger LB, Bounameaux H, Doerschug K, Geersing GJ, et al. Antithrombotic therapy for VTE disease: second update of the CHEST guideline and expert panel report. Chest. 2021;160(6):e545-e608. doi:10.1016/j.chest.2021.07.055.
6. Anderson DR, Morgano GP, Bennett C, Dentali F, Francis CW, Garcia DA, et al. American Society of Hematology 2019 guidelines for management of venous thromboembolism: prevention of venous thromboembolism in surgical hospitalized patients. Blood Adv. 2019;3(23):3898-3944. doi:10.1182/bloodadvances.2019000975.
7. Kahn SR, Comerota AJ, Cushman M, Evans NS, Ginsberg JS, Goldenberg NA, et al. The postthrombotic syndrome: evidence-based prevention, diagnosis, and treatment strategies: a scientific statement from the American Heart Association. Circulation. 2014;130(18):1636-1661. doi:10.1161/CIR.0000000000000130.