Treatment/management DVT

The aims of treatment are to relieve symptoms, reduce the risk of PE or paradoxical embolism to the systemic circulation, prevent post-thrombotic syndrome, and prevent recurrence.

Initial anticoagulation
Anticoagulation is the mainstay of treatment for DVT.
Initial treatment of DVT is heparin, as it is convenient to use and has a favorable side-effects profile. It can be used once or twice daily
LMWH (low molecular weight heparin) has a predictable anticoagulant response, so it can be given in a fixed weight-adjusted subcutaneous dose without laboratory monitoring in most patients. This allows out-of-hospital treatment in more than 80% of patients with acute DVT.
UFH (unfractionated heparin) is the treatment of choice in patients at high risk of bleeding or undergoing invasive procedures, and in patients with renal failure because of its shorter half-life, reversibility with protamine sulfate, and extra-renal metabolism.
In most cases, warfarin can be started on the first day. LMWH or UFH should be continued for at least 5 days and until the international normalised ratio (INR) has exceeded 2.0 on at least two occasions, 24 hours apart. Major bleeding occurs in 1%–5% of patients during initial treatment.
In patients with extensive ilio-femoral DVT and circulatory compromise, LMWH or UFH should be continued for at least 7 days, and initiation of warfarin should be delayed until anticoagulation has been therapeutic for several days.

Long-term anticoagulation
Warfarin (target INR, 2.0–3.0) is the anticoagulant of choice for long-term treatment of most patients with DVT, because it can be given orally and is highly effective, reducing the risk of recurrent VTE by 80%–90% during treatment.
In patients with provoked DVT, the risk of recurrent VTE after discontinuation of warfarin is 1%–4% per year. Generally, warfarin treatment should be continued for 3 months, although there is some evidence that 6 weeks treatment is as effective as 3 months in patients with provoked distal DVT.
In patients with unprovoked DVT, major chronic predispositions, or active malignancy, the risk of recurrent VTE after discontinuation of warfarin is substantially higher (at least 5%–10% per year) than for provoked events (≤ 4% per year). Decisions regarding the duration of anticoagulant treatment should be individualised by balancing the absolute risk of recurrent VTE with the potential absolute benefits (80%–90% relative risk reduction) and cumulative risks of bleeding associated with anticoagulation.

Thrombolytic therapy and surgical embolectomy
Compared with heparin, thrombolysis improves vein patency and reduces the risk of post-thrombotic syndrome, but increases the risk of bleeding, and there is no evidence of a net clinical benefit. Thrombolysis and surgical embolectomy have been used as limb-saving therapy in patients with extensive proximal DVT and circulatory compromise or venous gangrene.

Vena cava filter
Inferior vena cava filters are indicated to prevent pulmonary embolism in patients with DVT who are ineligible for anticoagulant therapy or who experience embolism despite adequate anticoagulation. Filters do not obviate the need for anticoagulation because they are associated with an increased risk of recurrent DVT. However, the optimal duration of anticoagulation in patients with vena cava filters in whom anticoagulation is deemed safe is uncertain.

Graduated compression stockings
Graduated compression stockings reduce the risk of post-thrombotic syndrome and should be used in the absence of contra-indications (eg, pre-existing leg ulceration or extensive varicosities).
And PE

Acute high-flow oxygen unless significant COPD, bed rest and analgesia. Severe cases IV fluids and ionotropic agents to improve right heart, very ill require ICU.

Prevention of furtheur emboli
• IV heparin, initial large bolus then continue infusion at a lower rate.
• LMWH, UFH have shown no difference in prevention of further emboli
• Oral anticoagulants begun after 48 hours, continue for 6 weeks – 6 months. Heparin is tapered off. Can be continued lifelong.
Dissolution of the thrombus
• Fibrinolytic therapy e.g. streptokinase following major embolism. Hourly up to 12- 72 hours.
• Surgical embolectomy is rarely necessary
Contraindications for anticoagulation and risk factors for anticoagulation-associated haemorrhage

Absolute contraindications

Active bleeding
Relative contraindications
Recent bleeding
Gastrointestinal bleeding within 2 weeks (eg, bleeding peptic ulcer)
Intracranial bleeding within 3 months
Recent major trauma
Bleeding diathesis
Coagulation defect
Severe thrombocytopenia (< 50 × 109/L); inherited or acquired platelet function defect
Uncontrolled hypertension
Endocarditis

Risk factors for anticoagulation-associated haemorrhage
Increasing age
Alcoholism
Cognitive impairment
Chronic corticosteroid use
Liver disease
Peptic ulcer disease
Polymorphisms for the gene encoding the hepatic microsomal enzyme CYP2CP and mutations of Ala-10 in the factor IX propeptide
References
• http://www.mja.com.au/public/issues/182_09_020505/ho10889_fm.html#elementId-1089801
• Kumar and Clarke 5th edition pg, 807 and 832

Sarah