Thromboembolism

Appropriate assessment

Virchow's Triad: Risk in Cancer

Explain to patient and family

Correct reversible factors

Consider disease-specific treatment

Pharmacological intervention for DVT

Venous thromboembolism (VTE) comprising deep venous thrombosis (DVT) and pulmonary embolism (PE) is a leading cause of death after admission to hospital. VTE is commonly seen in patients with disseminated malignancies and is therefore a frequent problem in the palliative care setting. Studies have suggested that the incidence of DVT may be 52% in palliative care. DVT is also at least 10 times higher in HIV-infected patients, especially when their CD4 count is less than 200 cells/μl. 

Appropriate assessment 

Patients at risk include: 

• Previous episodes of VTE 
• Malignancy 
• Dehydration 
• Age ˃ 60 years 
• Major surgical procedures 
• Hormone replacement therapy 

Symptoms and signs: 

• Painful leg 
• Swollen leg 
• Unexplained chest pain and 
• Sudden onset dyspnoea (indicating PE) 

Diagnosis: 

• High index of suspicion 
• Best achieved at acute care facility 
• Duplex Doppler studies 
• V/Q scan of lungs if suspecting PE 
• D-dimer blood test
  

Explain to patient and family 

Explain risks and benefits of treatment to patient and family. 

Discuss preventative measures such as exercising the lower calf muscles, keep active and move if possible, walking, lifestyle changes including stop smoking, lose weight, control blood pressure if these are a problem; it may be appropriate to wear compression stockings on your doctor’s advice. 

Correct reversible factors 

VTE is a treatable and largely preventable disease. For most terminally ill patients whose prognosis exceeds a few days and who have significant symptoms of a DVT, anticoagulation should be offered. 

Major contraindications include active gastrointestinal haemorrhage, active bleeding from any other site, an intracranial neoplasm and uncontrolled hypertension. 

Consider disease-specific treatment 

• Treat specific causes 
• Assess patients for prophylaxis according to: 
  • Their individual VTE risk 
  • Their clinical condition 
  • Their risk of bleeding 
  • The appropriateness of the prophylaxis for the individual patient 

Prophylaxis is indicated for high risk patients being hospitalised for major surgery and for long periods of bed rest. 

• Low molecular weight heparin (LMWH) and graduated compression stockings (GCS) for hospitalised patients. 
• GCS for home-based care patients. 
• Aspirin may have, at best, only a weak protective effect against development of DVT and is not generally recommended for this purpose. 

Pharmacological intervention for DVT 

Initiation of anticoagulation: LMWH offers definite advantages over unfractionated heparin in terms of convenient dosing, no need for monitoring and the possibility of outpatient management. It may also result in a reduced risk of recurrence. 

• Enoxaparin sodium (Clexane®) 1mg/kg s.c. bd (in renal impairment 1mg/kg s.c. daily) or dalteparin sodium (Fragmin®) 2500U -5000U/day 
• Warfarin should be started at a dose of 5 mg po daily from day 2 of anticoagulation. 
• The INR should be measured 2-3 days after starting Warfarin and then daily with dose adjustments to achieve a therapeutic range of 2-3 (for most indications) 
• LMWH must be given for at least 7 days even if the INR has reached therapeutic level 
• LMWH can be discontinued once the INR has been in the therapeutic range for two consecutive days. 
• For massive thrombosis or pulmonary embolism LMWH should be given for at least ten days. 
• For massive PE, thrombolytic therapy should be initiated. 

Duration of oral anticoagulation: This needs to be individualised according to the patient’s thrombo-embolic risk level and only basic recommendations are given. 

• Patients with reversible or time-limited risk factors should be treated for at least 3 months. 
• Patients with idiopathic DVT and all patients with PE should be treated for at least 6 months. 
• Patients with recurrent idiopathic VTE, continuing risk factors, life-threatening event or thrombosis in an unusual site will probably benefit from longer duration anticoagulation, probably life-long in some patients. However, this needs to be individualised and consideration should be given to the ability of both the prescribing physician and the patient to maintain a stable INR. 
• For most terminally patients anticoagulation should be ongoing. 

Outpatient management: management of VTE in the outpatient setting is safe and cost-effective provided that: 

• The patient is able to understand and administer therapy him/herself. 
• The patient is able to attend regular follow-up. 
• There are no complicating factors, e.g. an increased bleeding risk. 
• There is adequate compression treatment (with graduated compression stockings) 

Management of non-therapeutic INRs: The following are general guidelines. 

• INR ˃3˂5, no significant bleeding 
  • Omit warfarin 
  • Re-start lower dose once the INR is in the therapeutic range 
• INR˃5˂10 no significant bleeding 
  • Omit warfarin 
  • Monitor INR daily until back in the therapeutic range 
  • Restart Warfarin at a lower dose 
  • Consider low-dose oral vitamin K if INR remains prolonged 
• INR˃10 no significant bleeding 
  • Stop Warfarin 
  • Give vitamin K 2mg orally 
  • Monitor INR daily until in the therapeutic range (repeat vitamin K as required) 
  • Restart Warfarin at a lower dose 
• Patients with significant bleeding 
  • Stop Warfarin 
  • Give fresh-frozen plasma (FFP) at a dose of 15ml/kg or prothrombin complex concentrate (if the bleeding is life-threatening) 
  • Give vitamin K 1 mg slowly IV 

Special caution should be exercised when reversing anticoagulation in patients with prosthetic heart valves and should be done in consultation with the cardiologist. 

Monitoring of INRs 

• The INR should be monitored weekly at 
  • The local clinic or 
  • Private pathology laboratory