PART II (11-12 h flights): 132 participants randomized into two groups: the control group had no prophylaxis and the treatment group wore Kendall below-the-knee GCS. 30 participants with edema-related microangiopathy (10 with diabetes, 10 with chronic venous insufficiency and venous hypertension, and 10 on antihypertensive treatment with ACE inhibitors for hypertension) were included to evaluate the effects of GCS during the flights. The same procedures and criteria were adopted as had been used in part I. The gene discussed is ACE; the disease is chronic venous insufficiency.