Thousands of NHS patients are still dying unnecessarily because of a lack of awareness of the risk of developing fatal blood clots after an operation.

The condition, venous thromboembolism (VTE), causes one in ten fatalities in British hospitals — an estimated 500 people a week, more than MRSA infections, breast cancer, HIV and road accidents combined.

But only one in three NHS hospitals is properly assessing which patients are at risk, while the public are also largely unaware of the dangers, campaigners say.

As many as half of all patients going into hospital are at risk of developing VTE, which occurs when part of a deep-vein thrombosis or blood clot migrates to the lungs, heart or brain. Such clotting is common after surgery, especially in the elderly, the overweight or those confined to bed for more than three days.

The National Institute for Health and Clinical Excellence (NICE) issued guidelines for the NHS in 2007 recommending that all patients should be assessed on admission to hospital for their risk.

But MPs say that while most patients admitted for common operations such as hip and knee replacements are now assessed by a healthcare professional or treated with anti-clotting drugs before the procedure, many other patients are not offered such preventive checks or made aware of the risks.

John Smith, chairman of the cross-party parliamentary thrombosis group, said: “Despite the Health Select Committee announcing the urgent need for action to stem the number of deaths from hospital-acquired blood clots four years ago, a third of NHS hospitals is still not carrying out proper risk-assessments on their patients.”

A survey of more than 1,000 patients by the thrombosis charity Lifeblood found that fewer than one in three were concerned about the risks of VTE when going into hospital, compared to three quarters who would be concerned about contracting a “superbug” infection such as MRSA.

The Department of Health said that while routine screening of patients was not a mandatory requirement, it would consider introducing legislation if the situation did not improve.

Ann Keen, the Health Minister, said that she expected the VTE risk assessment policy to be adopted throughout the NHS and that experts were visiting every trust in England to discuss the implementation of the checks.

“We will be monitoring the position closely and formally reviewing the policy in a year’s time,” she added. “If there is inconsistency... or lack of commitment, we will consider making it mandatory to perform risk assessments.”

Professor Beverley Hunt, Lifeblood’s medical director, said that more than 70 per cent of deaths due to VTE were preventable with proper awareness and treatment. She urged all patients going into hospital for a planned operation to talk to their doctor about the risks and symptoms.

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