VTE risk is a common, but preventable, complication
Although many associate venous thromboembolism (VTE) with recent trauma or surgery, 50% to 70% of symptomatic cases, as well as the majority of cases of fatal pulmonary embolism (PE), occur in medical (nonsurgical, nontrauma) patients. Because of the often silent nature of VTE, the first sign of a problem may be a clinically significant event, such as PE.
Cancer and other medical illness are major contributors to VTE risk
Cancer, in particular, is a major risk factor, as one in five diagnosed cases of VTE occurs in a person with cancer.
Immobilisation increases the risk of VTE
Hospitalised medical patients are often immobile because of weakness, reduced alertness, or nerve injury. In addition, patients in critical care settings are often bedridden. Even in the absence of medical illness, lack of mobility can lead to venous stasis and VTE, as can occur during long-distance air travel.
Conditions commonly associated with hospitalisation that increase risk of VTE
- Stroke
- Congestive heart failure (NYHA Class III-IV)
- Acute respiratory disease
- Acute myocardial infarction
- Acute arthritis
- Acute infection
- Inflammatory bowel disease
Patient-related, predisposing characteristics that increase risk of VTE
- Recent surgery or major trauma
- Immobility or paralysis
- Malignancy
- Previous VTE
- Older age, particularly >80 years
- Oestrogen therapy (contraceptives or hormone replacement)
- Obesity
- Central vein catheterisation
- Varicose veins
- Inherited or acquired thrombophilia
Age, in particular, is a one of the most important risk factors for VTE. The risk increases exponentially over time, from a negligible rate in children under 15 (<5 per 100,000) to a rate of ~500 per 100,000 in those over 80.
Hospitalised patients often have multiple risk factors for VTE
Patients hospitalised because of medical illness often have multiple risk factors for VTE, and these risks are generally cumulative.Accordingly, all patients should be evaluated for their risk of VTE at the time of hospital admission. This evaluation should be repeated whenever there is a significant change in a patient’s clinical status.
Preventive treatment can reduce incidence of VTE
Prospective studies have shown that hospitalised medical patents at high risk who do not receive preventive anticoagulant therapy develop deep vein thrombosis (DVT) in the calf in 10% to 15% of cases. The same studies revealed an incidence of proximal DVT in 2% to 5% and of PE in 0.3% to 1.5%.
Studies have also shown that anticoagulant prophylaxis reduces the risk of symptomatic VTE in hospitalised medical patients. Despite the clear need for prophylactic care to prevent VTE in high-risk medical patients, a recent multinational, cross-sectional audit revealed that fewer than 40% of hospitalised medical patients at risk received standard VTE prophylaxis. Therefore, timely risk assessment and preventive therapy is the optimal therapeutic approach.
VTE risk associated with cancer
VTE is a leading cause of death in patients with cancer. The incidence of symptomatic VTE in patients with malignancies ranges from 4% to 20% depending on the study.Certain medications used to treat cancer, such as tamoxifen and erythropoietin, increase the risk of VTE. In addition, novel chemotherapeutic agents that suppress blood vessel formation (eg, thalidomide, lenalidomide, and bevacizumab) have been associated with a high rate of VTE.
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