DVT and Immobilization ====================== þ Long travel isn't really much of a risk: - In a large cohort of symptomatic ED patients, risk of venous thromboembolism was substantially increased by presence of limb, whole-body, or neurologic immobility but not by travel greater than 8 hours. These data show the importance of clarifying the cause of immobility in risk assessment of venous thromboembolism. [Beam DM, Courtney DM, Kabrhel C, Moore CL, Richman PB, Kline JA. Risk of Thromboembolism Varies, Depending on Category of Immobility in Outpatients. Annals of emergency medicine 2009;54:147-52.] þ DVT risk after air travel linked to prior risk factors (Reuters Health) - The risk of venous thromboembolism (VTE) is mildly elevated by air travel lasting 6 hours or more, according to three reports in the Archives of Internal Medicine for December 8/22. However, there is a multiplicative effect between air travel and established risk factors, such as thrombophilia or use of oral contraceptives. Moreover, the risk of pulmonary thromboembolism (PTE) is significantly higher after long-haul flights, but the absolute risk is still quite low. "Special precautions are probably not required for flights less than 6 hours, but may become appropriate when passengers with risk factors for PTE embark on prolonged flights of 6 hours or longer," Dr. David Jimenez, with the Ramon y Cajal Hospital in Madrid, and his associates write. In one study, Dr. Ida Martinelli and colleagues at the University of Milan, Italy, identified 210 patients who had experienced an episode of proximal VTE or PTE in the last 24 months. Control subjects with no history of thrombosis were matched for age, gender and education level. Air travel in the month prior to thromboembolism doubled the risk for VTE, reported by 15% of patients and 8% of controls. Risk was tripled when considering only flights of 8 hours' duration or longer. Compared with individuals who did not fly and did not have thrombophilia, the risk of VTE was 6 times higher in patients with thrombophilia, but 16 times higher in those with both risk factors. Similarly, oral contraceptive use increased the risk of VTE 4-fold, while the risk was 14 times higher among OC users who flew. Meanwhile, a team of researchers at the University Hospital of Dresden Medical School, Germany, led by Dr. Thomas Schwarz, conducted a prospective cohort study that included 964 individuals who underwent venous compression ultrasonography a week before and within 48 hours after air flights lasting 8 hour of more. Similar examinations were conducted in 1213 non-traveling control subjects. Venous thrombotic events were documented in 27 (2.8%) passengers and 12 (1.0%) controls. However, Dr. Schwartz' team notes, the elevated risk applied "only to individuals with preexisting permanent risk factors." Dr. Jimenez's group in Madrid limited their study to international travelers in whom PTE was diagnosed over a 6-year period. Out of the nearly 7 million passengers per year on international flights, only 16 were diagnosed with PTE. The risk was elevated only among those whose flights lasted 6 hours or more. Thus, "the incidence does not justify the social alarm created around air travel caused by the risk of developing PTE," they write. All three research groups concur with the conclusions of Dr. James E. Dalen in his editorial, that individuals at risk should walk around during extended travel and consider using compression stockings. The evidence suggests that those with thrombophilia may benefit from prophylactic anticoagulation. Copyright 2003 Reuters Limited. All rights reserved. Republication or redistribution of Reuters content, including by framing or similar means, is expressly prohibited without the prior written consent of Reuters. Reuters shall not be liable for any errors or delays in the content, or for any actions taken in reliance thereon. Reuters and the Reuters sphere logo are registered trademarks and trademarks of the Reuters group of companies around the world.