The LONFLIT4-VENORUTON study: a randomized trial prophylaxis of flight-edema in normal subjects.

This study evaluated the protective effects of Venoruton on the development of flight edema in normal subjects travelling in economy in long-haul flights (8-9 hours). Edema is a relevant aspect of long-haul flights affecting both venous patients and normal subjects. Edema and flight microangiopathy were studied in a group of 164 subjects randomized (after informed consent) into two groups to evaluate prophylaxis in 8- to 9-hour flights. The treatment group received Venoruton (hydroxyethyl rutosides) 1 g twice daily for 3 days (2 days before the flight and the day of the flight). The control group received comparable placebo. Edema was evaluated with a composite edema score based on the edema tester, on the measurements of ankle circumference, volume measurements, subjective swelling, and on a discomfort score. Items 1, 4, and 5 are based on an analogue scale line (1 to 10) directly defined by the subjects before and after the flights. Of the included subjects, 151 completed the study. Dropouts were due to poor compliance, travelling, or connection problems. Age and gender distribution were comparable in the two groups as were risk factor distributions. The level of edema at inclusion was comparable in the two groups of subjects. After the flight there was an average score of 6.7 (SD 1.7) in the control group, while in the Venoruton group the score was on average 3 (SD 1.1) (p < 0.05). In the control group 77% of the subjects had an evident increase in ankle circumference and volume, which was clearly visible at inspection and associated with discomfort. In the Venoruton group, edema was clearly present only in 8% of subjects (associated with discomfort rated between 3 and 6 on the analogue scale line) and it was mild, not associated with symptoms. Therefore the control of flight edema with Venoruton was clear both considering parametric data (circumference and volume) and non-parametric (analogue scale lines) measurements. The combined evaluation of the edema score is significantly favorable for subjects under prophylaxis with Venoruton.