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Aspirin as effective as NOACs for VTE post hip and knee operations

Aspirin is a cheap and safe alternative to oral anticoagulants for treating venous thromboembolism, after hip and knee replacements, new research has found.

The study included over 3,000 patients who were undergoing either surgery, and found that switching from a branded oral anticoagulant to generic aspirin five days after the operation did not increase the risk of blood clots.

Currently patients who have a total hip or knee arthroplasty are prescribed oral anticoagulants to prevent VTE, for up to five weeks after their surgery.

However researchers are now suggesting that patients could be safely switched to aspirin after a short period on an oral anticoagulant.

All the study participants received a once-daily oral rivaroxaban for the first five days after surgery, and were then randomly assigned to continue rivaroxaban or switch to aspirin. The treatments were continued for an additional 9 days for knee patients and 30 days for hip, with the team then following up with the patients after 90 days.

The paper, published in the New England Journal of Medicine, found that VTE occurred in 0.64% in the aspirin group and 0.70% in the rivaroxaban group. They concluded that ‘extended prophylaxis with aspirin was not significantly different’.

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Study author and Dalhousie University faculty of medicine dean, Professor David Anderson said: ‘Aspirin would be attractive for this indication because of its low cost, ease of use, and low rates of side effects.

‘Aspirin is an effective and safe alternative to oral anticoagulants for extended prophylaxis, following total hip or knee arthroplasty, in patients who receive a short course of oral anticoagulants following surgery.’

Professor Anderson has now called for further research to determine whether aspirin could be used as an alternative to oral anticoagulants for the entire post-operative course.

University College London Professor of Haematology Dr Machin commented: ‘It’s a well conducted study, with prominent authors and the statistics look very good.

‘The cost savings could be considerable. It’s something that orthopaedic surgeons should consider.’

Last month, GPs were told they should compare the risks and benefits before prescribing patients anticoagulants, after a study found that chronic kidney disease patients who also had atrial fibrillation, were almost three times more likely to suffer a stroke, and over twice as likely to experience a haemorrhage, when taking the drug.


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