Talk about a brutal coincidence. Dr. John Royle will never forget that grey August morning in 1993 when the Melbourne vascular surgeon was climbing the hill between his consulting rooms and operating theatre at Austin Hospital. It was a routine walk for the then fit 59-year old who had only the day before flown back home from a conference in Hawaii, where he had presented a paper suggesting Australians could be at greater risk of flight-related deep vein thrombosis (DVT) then previously believed.

The phenomenon had already touched Royle personally; one of his colleagues had recently died after a long-haul flight and the father of one of his daughter's schoolmates had been struck down by a fatal DVT soon after returning home on a flight from Europe. But Royle's customary stride was interrupted by a sharp, cramping pain in his left calf. Ten seconds. Maybe 20. That's all it took for him to recognize the telltale signs of a thrombus (blood clot) in a deep vein of his leg which he knew had a risk of breaking free from the vein wall and traveling to his heart or lungs, where it could block the flow of blood and cause a fatal pulmonary embolism. Royle took a detour to the hospital's lab for an ultrasound, where it was found he had a six-to-seven centimetre long clot in his leg which, although not life-threatening, had a risk of lengthening. Royle was immediately hooked up to a drip of an anti-coagulant drug and confined to the hospital for five days.

DVT only turned into a front-page issue last October 2000 when a fit and active 28 year-old Englishwoman died shortly after stepping off a flight from Sydney to London. That seemingly isolated case swiftly topped a short casualty list. A British businesswoman collapsed and died at San Francisco within weeks of the earlier death mentioned above, a 68-year-old British tourist slipped into a coma and died after a 20 hour flight from London to Melbourne plus two others who suffered fatal DVT's while enroute to London in 1999 and 1998 respectively. And Greggs article mentions many more. There are some 20 million airbourne journeys to and from Australia each year, and how many others are taking long-haul flights to other countries in which similar conditions are evident? Although Australian hospitals do not record whether blood clot patients had been recently on an aircraft, Dr. Reginald Lord, a vascular surgeon at St. Vincent's Hospital in Sydney and possibly Australia's foremost expert on DVT, estimates that up to 400 people a year could be arriving in Sydney with flight-related DVT. St. Vincent's treats about 40 per DVT cases per year, "almost one a week". How many other cases do you suppose go unreported and untreated in other countries?

Deep vein thrombosis (DVT) is a common but elusive illness that can result in suffering and death if not recognized and treated effectively. DVT occurs in ~2 million Americans each year. Death can occur when the venous thrombi break off and form pulmonary emboli, which pass to and obstruct the arteries of the lungs. DVT and pulmonary embolism (PE) most often complicate the course of sick, hospitalized patients but may also affect ambulatory and otherwise healthy persons.1-4 It is estimated that each year 600,000 patients develop PE and that 60 000 die of this complication.5-7 This number exceeds the number of American women who die each year from breast cancer. PE is now the most frequent cause of death associated with childbirth. Women are a prime target for PE, being affected more often than men.

Deep vein thrombosis is a major complication in orthopedic surgical patients and patients with cancer and other chronic illnesses. DVT can be a chronic disease. Patients who survive the initial episode of DVT are prone to chronic swelling of the leg and pain because the valves in the veins can be damaged by the thrombotic process, leading to venous hypertension. In some instances skin ulceration and impaired mobility prevent patients from leading normal, active lives. In addition, patients with DVT are prone to recurrent episodes. In those instances in which DVT and PE develop as complications of a surgical or medical illness, in addition to the mortality risk, hospitalization is prolonged and healthcare costs are increased.

There is no doubt about it that DVT is real. Yes, in Australia there are an estimated 2,500 that are claiming they suffered blood clots after flying, and there probably could be many thousands more throughout the world. However, our concern here, in this brief article, is not how to enrich the lawyers but to bring this to the attention of those who do a lot of traveling enabling them to take precautions for their own health. What about you? If you fly long-haul you may be at risk, and perhaps you should take precautions or at least get yourself checked?

With over 1 million passengers at any one time in the air and up to 10% medically unfit to fly, according to one estimate, problems both minor and serious are just as likely to happen at 7000 ft. as on the ground. Regardless of whether you are sitting in an airplane high in the sky or on the ground at the movies - one is suscptible to DVT, because the rate of blood flow to your lower limbs is reduced by about two thirds. According to sme estimates, there are about 2,000 passengers that die from the condition every year. "The airlines are not in the business of scaring people, " says Andrew Keller, Director of the Airport Medical Centre at Sydney's Kingsford Smith airport, who sees one person a day with leg swelling and perhaps one every two months with actual DVT. "There's always the risk of a terrorist boarding an aircraft: do you warn passengers about that too?"

More leg room on long-distancce flights would NOT solve the problem of DVT. At a recent summit attended by representatives from 16 major airlines, concluded there was a "probable link" between passengers on long flights who suffered potentially fatal blood clots. Australian researchers have noted a "serious lack of definitive information" on the instances of DVT and pulmonary embolism. Alex Gallus, a professor of Haematology and Director of Pathology and Ross Baker, Director of thrombosis and Haemophilia Service at Royal Perth Hospital, also have exploded the myth of "economy class syndrome". "Business and first-class passeengers are not immune (to DVT), so more generous seating space is unlikely to be the answer and "economy class syndrome" is likely to be a misnomer" the professors wrote in the latest Medical Journal of Australia. On long flights the professors recommend regular foot exercises, generous fluid intake, loose fitting clothing, and avoid drinking too much alcohol.

WHAT IS DVT? Deep Vein Thrombosis or DTV happens when blood clots form in the calf or thigh after prolonged sitting (especially on long-haul airline flights). The leg swells and may become red and painful to the touch. The blood clot breaks away from the wall of the vein when the sufferer starts moving around. The clot is carried along with the blood and partly or completely blocks the flow of blood in the vein. If the blockage travels to the lungs, it may cause chest pain, breathing difficulties and possibly death!(Schematic picture)

WHAT ARE THE SYMPTOMS? Sharp pain when the foot is flexed upwards, tenderness and swelling in the leg, fever, rapid heartbeat, sudden unexplained cough and joint pain. The leg may become red and warm to the touch.

WHO IS MOST AT RISK? Those aged over 40 years, the obese or overweight; those with blood disorders leading to increased clotting; pregnant women; smokers, cancer and heart disease sufferers, those with a family history of DVT, those who have had recent surgery or injury to a lower limb, women on hormone replacement therapy, those on the pill, people with varicose veins.