Risk factors and associated increased risk for development of venous thromboembolism in surgical patients

Risk Factor

Associated Increased Risk

Age

Exponential increase in risk with age in the general population:

< 40 years results in Annual risk 1/10,000

60-69 years results in Annual risk 1/1,000

> 80 years Annual risk 1/100

Obesity

if BMI > 30 kg/m^2 then Three times

Previous VTE

Recurrence rate of 5% per year, increased by surgery

Malignancy

Seven times

Hormone therapy

HRT results in two-three times

oral contraceptives results in three times

tamoxifen results in three times

high dose progestogens results in six times

raloxifene results in three times

Pregnancy

ten times increased risk

Immobility

Bed rest > three days, plaster casts and paralysis -> result in ten times

Hospitalisation

Acute trauma, acute illness and surgery > result in ten times

• Active cancer or cancer treatment
• Age over 60 years
• Critical care admission
• Dehydration
• Known thrombophilias
  • inherited thrombophilias, for example:
    • High levels of coagulation factors (for example, Factor VIII)
    • Hyperhomocysteinaemia
    • Low activated protein C resistance (for example, Factor V Leiden)
    • Protein C, S and antithrombin deficiencies
    • Prothrombin 2021A gene mutation.
• Obesity (body mass index [BMI] over 30 kg/m2)
• One or more significant medical comorbidities (for example: heart disease; metabolic, endocrine or respiratory pathologies; acute infectious diseases; inflammatory conditions)
• Personal history or first-degree relative with a history of VTE
• Use of hormone replacement therapy
• Use of oestrogen-containing contraceptive therapy
• Varicose veins with phlebitis
• For women who are pregnant or have given birth within the previous 6 weeks see Box 2

• consider offering pharmacological VTE prophylaxis with LMWH (or UFH for patients with renal failure) to women who are pregnant or have given birth within the previous 6 weeks who are admitted to hospital but are not undergoing surgery, and who have one or more of the following risk factors:
  • expected to have significantly reduced mobility for 3 or more days
  • active cancer or cancer treatment
  • age over 35 years
  • critical care admission
  • dehydration
  • excess blood loss or blood transfusion
  • known thrombophilias
  • obesity (pre-pregnancy or early pregnancy BMI over 30 kg/m2)
  • one or more significant medical comorbidities (for example: heart disease; metabolic, endocrine or respiratory pathologies; acute infectious diseases; inflammatory conditions)
  • personal history or a first-degree relative with a history of VTE
  • pregnancy-related risk factor (such as ovarian hyperstimulation, hyperemesis gravidarum, multiple pregnancy or pre-eclampsia)
  • varicose veins with phlebitis.
• consider offering combined VTE prophylaxis with mechanical methods and LMWH (or UFH for patients with renal failure) to women who are pregnant or have given birth within the previous 6 weeks who are undergoing surgery, including caesarean section
• mechanical and/or pharmacological VTE prophylaxis should be offered to women who are pregnant or have given birth within the previous 6 weeks only after assessing the risks and benefits and discussing these with the woman and with healthcare professionals who have knowledge of the proposed method of VTE prophylaxis during pregnancy and post partum. Plan when to start and stop pharmacological VTE prophylaxis to minimise the risk of bleeding