Thrombosis - Prevention

Prevention

Prophylaxis of venous thromboembolism with heparin in medical patients does not appear to decrease mortality and while it may decrease the risk of pulmonary embolism and deep vein thrombosis it increases the risk of bleeding and thus results in little or no overall clinical benefit. Mechanical measures also appeared of little benefit in this group and in those with a stroke resulted in harm. Evidence supports the use of heparin following surgery which has a high risk of thrombosis to reduce the risk of DVTs; however the effect on PEs or overall mortality is not known.

Generally, a risk-benefit analysis is required, as all anticoagulants lead to a small increase in the risk of major bleeding. In atrial fibrillation, for instance, the risk of stroke (calculated on the basis of additional risk factors, such as advanced age and high blood pressure) needs to outweigh the small but known risk of major bleeding associated with the use of warfarin.

In people admitted to hospital, thrombosis is a major cause for complications and occasionally death. In the UK, for instance, the Parliamentary Health Select Committee heard in 2005 that the annual rate of death due to hospital-acquired thrombosis was 25,000. Hence thromboprophylaxis (prevention of thrombosis) is increasingly emphasized. In patients admitted for surgery, graded compression stockings are widely used, and in severe illness, prolonged immobility and in all orthopedic surgery, professional guidelines recommend low molecular weight heparin (LMWH) administration, mechanical calf compression or (if all else is contraindicated and the patient has recently suffered deep vein thrombosis) the insertion of a vena cava filter. In patients with medical rather than surgical illness, LMWH too is known to prevent thrombosis, and in the United Kingdom the Chief Medical Officer has issued guidance to the effect that preventative measures should be used in medical patients, in anticipation of formal guidelines.