1 in 10 flyers risk clots

By MONIQUE DEVEREUX health reporter

One in 10 long-haul air travellers may develop potentially dangerous blood clots without realising it, new research shows.

The same study may also have found a simple way to prevent the blood clots - also known as economy class syndrome - from developing at all.

British vascular surgeon Dr John Scurr published the results of his pilot study into deep vein thrombosis (DVT) in air travellers in Friday's edition of the prestigious British medical journal Lancet.

He recruited 200 travellers for the study, all of whom were over the age of 50 and had no history of blood clots.

The volunteers were given blood tests and ultrasounds before their flights - which had to be two legs of at least eight hours, completed within six weeks - and again afterwards at London's Stamford Hospital.

The passengers were split randomly into two groups, and almost half were given medical compression stockings to wear in-flight.

Twelve of the 116 passengers without stockings developed blood clots in their legs. The clots can be fatal if they move to the lungs.

None of the 84 passengers who wore the compression stockings developed the clots.

The stockings are used in hospitals after surgery to prevent blood clots.

The passengers who had developed blood clots in their legs were treated, eight with aspirin and the other four with more specific medication.

Several months ago, Dr Scurr told the Herald that the stockings were a viable alternative to walking around an aircraft cabin during long-haul flights.

He also recommended that travellers practise in-seat leg exercises.

Dr Scurr acknowledged that his research, which took 18 months to complete, studied a relatively small number of people, and that none of the travellers had developed life-threatening clots.

"We accept the symptomless calf vein thrombosis is probably not a major risk to health, but the approach might be useful in future interventional studies to be done."

A New Zealand study into the links between air travel and fatal blood clots - possibly the world's most comprehensive yet - is to begin at the end of this month.

About 1000 volunteers will be needed for the study, which will be conducted by doctors from Green Lane and Wellington Hospitals. It aims to find out exactly who is in danger of developing economy class syndrome and why.

Dr Rodney Hughes, a senior respiratory registrar at Green Lane, will head the $250,000 study.

Economy class syndrome has received widespread publicity in recent months, since a 28-year-old British woman collapsed and died after flying from Sydney to London. About 1000 people, including 11 New Zealanders, are suing airlines over DVT.

Herald Online feature: Economy class syndrome