Prophylaxis of Venous Thromboembolism

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Prophylaxis of Venous Thromboembolism

• Dr Galila Zaher
• Consultant Hematologist
• MRCPATH

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VTE in medical patients

• 600,000 patients / year are hospitalized for DVT.
  symptomatic PE 600,000 patients and causes .
• contributes to death 200,000 annually.
• Most fatal PE occur in medical patients.
• A small number of randomised trials compared with
  that of surgical patients.
• Meta-analyses in MI ,stroke and other medical
  patients have clarified the benefits of
  thrombo-prophylaxis .

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• 85 of all medical patients admitted to an acute
  care hospital are eligible and/or suitable for
  DVT prophylaxis

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ACUTE MYOCARDIAL INFARCTION

• Prior to the introduction of routine
  antithrombotic therapy .
• Acute MI had a risk of asymptomatic DVT of 24,
  and PE of 2-9.
• The risk increases with age and in the presence
  of heart failure.

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MECHANICAL PROPHYLAXIS

• GENERAL MEASURES .
• Compression stockings especially when heparin
  prophylaxis is contraindicated. (grade
  A)

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ASPIRIN AND THROMBOLYTIC THERAPY

• Strongly recommended that all patients with
  acute MI should be given aspirin (150-300 mg) .
  (grade A)
• Strongly recommended that all patients with
  acute MI should be considered for thrombolytic
  therapy. (grade A)

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ANTICOAGULANTS

• Heparin not routinely in addition to aspirin in
  acute MI, but reserved for patients at increased
  thromboembolic risk (grade A)

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High risk of thromboembolism

• Large anterior Q-wave infarction.
• Severe left ventricular dysfunction.
• Congestive heart failure.
• History of systemic or PE or thrombophilia.
• Echo evidence of mural thrombus.
• Persistent AF.
• Prolonged immobilization.
• Marked obesity
• (grade A)

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ANTICOAGULANTS

• Full-dose heparin , followed with warfarin for up
  to three months.
• Bleeding risks outweigh the benefits,
  thrombo-prophylaxis low-dose SC heparin (7,500 IU
  12-hourly) for seven days or until ambulant.
• (grade A)

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Acute stroke

• Asymptomatic DVT 50 of acute hemiplegic stroke.
• Clinically apparent DVT or PE lt5.
• PE may account for up to 25 of early

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General measures

• Early mobilization and hydration .
• Meta-analysis of haemodilution VTE was reduced,
  despite lack of overall benefit.

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MECHANICAL PROPHYLAXIS

• Graduated compression stockings justified for
  high risk patients.
• (grade C)
• Compression stockings are preferred haemorrhagic
  stroke.
• (grade D)
• Intermittent pneumatic compression no evidence
  effective .
• Intermittent pneumatic compression is effective
  in patients undergoing neurosurgery .

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ASPIRIN

• Significant decrease in death or dependency.
• Aspirin significantly reduced PE from 0.5 to
  0.3.
• Aspirin is started as soon as ICH is excluded
  by CT or MRI. (grade A)
• Aspirin can be given by NG tube or rectally
  unable to swallow.

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ANTICOAGULANTS

• Systematic reviews RCTs .
• Heparin reduces asymptomatic DVT after stroke.
• Prevention of DVT PE is offset by an increase in
  haemorrhagic complications.
• The bleeding risk is dose-related.
• If heparins are to be used , low dose should be
  selected
• LMWH preferred due to a lower risk of bleeding.
• UFH (5,000 IU SC BID) .
• LMWH .

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ACUTE MYOCARDIAL INFARCTION

• aspirin (150-300 mg).grade A
• thrombolytic therapy. Grade A.
• Heparin should not be used routinely but reserved
  for patients at increased thromboembolic risk
  grade A.
• Compression stockings especially when heparin
  prophylaxis is contraindicated grade A

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Acute stroke

• graduated compression stockings may be justified
  for some high risk patients. Grade C
• Compression stockings are preferred for patients
  with haemorrhagic grade D
• Aspirin as soon as intracranial haemorrhage is
  excluded by CT or MR brain scanning. Grade A
• Aspirin can be given by nasogastric tube or
  rectally for those who are unable to swallow.
• UFH or a LMWH at higher than average risk of VTE
  . Grade A

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Other medical patients

• low dose UFH or LMWH should be considered. grade
  A
• LMWH carries a lower risk of bleeding. grade A
• heparin prophylaxis is contraindicated, GECS may
  be considered grade C

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Cancer patients

• Minidose warfarin (1 mg/day, no INR monitoring)
  with central venous catheters. Grade A
• Low-dose warfarin (target INR 1.6, range 1.3-1.9)
  during chemotherapy in stage IV breast cancer.
  Grade A

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ANTICOAGULANTS

• In patients with ischaemic stroke at higher than
  average risk of VTE
• History of previous VTE.
• known thrombophilia .
• Active cancer.
• Lower than average risk of haemorrhagic
  complications.
  (grade A)

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Other medical patients

• Autopsy PE cause of deaths in immobilized
  patients in medical wards.
• Heparin 56 decrease in asymptomatic DVT PE
• The reduction in mortality was not statistically
  significant .
• The risk of major bleeding was higher
• LMWH as effective as UFH in reducing DVT, PE and
  mortality lower risk of major bleeding.

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Thrombo-prophylaxis in medical patients

• Heart failure.
• Respiratory failure .
• Infections. (chest infections).
• Diabetic coma.
• Inflammatory bowel disease.
• Nephrotic syndrome.
• Intensive care patients.
• Low dose UFH or LMWH .
• LMWH lower risk of bleeding.
  (grade A)

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MECHANICAL METHODS

• Significant risk of VTE prophylaxis is
  contraindicated, GECS may be considered.
   (grade C)

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Cancer patients

• Cancer patients have an increased risk of VTE.
• Central venous line thrombosis .
• Chemotherapy-induced thrombosis.
• Immobilised cancer in medical or surgical wards
  should be considered for prophylaxis.

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ANTICOAGULANTS

• Minidose warfarin (1 mg/day, no INR monitoring)
  in cancer patients with central venous catheters.
• 
  (grade A)
• Low-dose warfarin (target INR 1.6) during
  chemotherapy stage IV breast cancer.
• 
  (grade A)
• Patients receiving antipsychotic drugs

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• The Medenox study clearly showed a dose-effect
  relationship with enoxaparin and the
  ineffectiveness of the lower prophylactic dose
  trend toward mortality reduction with enoxaparin.
  did not reach statistical significance.

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• CONCLUSIONS
• Enoxaparin, given once daily at a dose of 40 mg
  subq once daily for 6-14 days reduces the risk of
  VTE by 63,
• without increasing the frequency of hemorrhage.
• Enoxaparin is the only LMWH with an approved,
  FDA indication for prophylaxis of DVT in medical
  patients.
• should be maintained for at least 7 days,

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• The majority of fatal PE have not undergone
  recent surgery.

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• MEDENOX confirmed the effectiveness of
  enoxaparin in preventing VTED in medical
  patients.
• In PRIME enoxaparin versus heparin new VTE
  0.2 and 1.4 .

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• Ageno et al. 112 patients with clinical
  indications for VTE prophylaxis without
  contraindications to anticoagulation prophylaxis
  was underprescribed.
• only 46.4 received thromboprophylactic treatment.