LONDON, March 6: Patients who have undergone major orthopaedic surgery were advised on Thursday not to travel long distances for up to three months afterwards because of the risk of fatal blood clots.

The recommendation — by a group of British legislators — follows research showing that travelling for more than three hours trebles the risk of deep vein thrombosis (DVT) if the traveller has had recent surgery.

John Smith, chairman of parliament’s All-Party Group on Travel-Related DVT, warned that patients often went off on holiday to recover after hip or knee replacement operations blissfully unaware of the risks of a long flight.

His warning was backed by Dr Ander Cohen, a vascular physician who recently investigated the association between long haul flights and DVT in 568 patients attending his clinic at King’s College Hospital, London.

Cohen told a news conference: “What we found was that travelling for more than three hours results in a three-fold increase in the risk of DVT if the traveller has an additional risk factor for DVT such as recent surgery.”

He said drugs to prevent DVT were usually only given for up to ten days after surgery even though the risk of DVT persisted for much longer. A Scandinavian study published last year found a highly significant 39 percent increase in the risk of death for up to 90 days after major orthopaedic surgery.

“This results in an excess death rate of one in every 240 patients. The commonest cause of death is pulmonary embolism (a clot in the lungs).”—Reuters