Increased white cell trapping in the dependent legs of patients with chronic venous insufficiency

Interest in white cell (WBC) rheology has largely been directed towards hypotensive conditions. However, as capillary flow is dependent on the relative arteriovenous pressure gradient, we investigated the dynamics of WBC flow in patients with venous hypertension. Three groups of matched subjects were studied: normal controls, patients with primary varicose veins, and patients with deep venous insufficiency confirmed by foot volumetry and Doppler studies. A venous cannula inserted at the level of the medial malleolus allowed blood samples to be taken at time 0 (supine) and then at 15, 30, 45, and 60 minutes after sitting up. Further samples were taken after subjects resumed a supine position. After 60 minutes sitting the haematocrit of blood leaving the foot increased by 9.6% in controls and 25.6% in patients with venous insufficiency. The difference in the behaviour of WBC was more marked. Controls showed a 5.0% decrease in the relative number of WBC after 60 minutes sitting compared to 28% decrease in patients with venous insufficiency. On resuming a supine position there was a significant increase in the number of WBC leaving the foot and this "wash-out" appeared to be delayed in the two patient groups. Platelets showed a corresponding fall when the foot was dependent but there appeared to be no washout after elevation.