AN ORIGINAL MICROHAEMORHEOLOGICAL APPROACH TO THE PHARMACOLOGICAL EFFECTS OF DAFLON 500 MG IN SEVERE CHRONIC VENOUS INSUFFICIENCY

In the more advanced stages of chronic venous insufficiency, stasis in the skin microcirculation is associated with a decreased red blood ce ll velocity and an increase in packed cell volume related to the red b lood cell piling phenomenon. Although the main factor determining bloo d viscosity is packed cell volume, the direct relationship between thi s variable, viscosity and velocity is no longer valid at the microcirc ulatory level (sigma effect). Viscosity is influenced by blood composi tion and red blood cell deformability. The aim of this open pilot stud y was to verify the variations in capillary packed cell volume in comp arison with the velocity in 24 patients with third-stage chronic venou s insufficiency before (day 1) and after (day 28) a 28-day treatment w ith Daflon 500 mg, a micronized purified flavonoid fraction consisting of diosmin, 450 mg, and hesperidin, 50 mg, per tablet, 1 g/day, and t hen 14 days (day 42) after cessation of treatment. Ankle skin microcir culation was evaluated by dynamic capillaroscopy. Values of relative c apillary packed cell volume were calculated by a densitometric method, and red blood cell velocity was calculated using the cross-correlatio n simplified method, Relative capillary packed cell volume (mean +/- S D) significantly (p = 0.001) increased from day 1 (64.10 +/- 9.34%) to day 28 (72.89 +/- 5.74%) and then decreased until day 42 (66.84 +/- 7 .48%). In the same patients, red blood cell velocity (mean +/- SD) sig nificantly (p = 0.041) increased from day 1 (0.26 +/- 0.14 mm/sec) to day 28 (0.35 +/- 0.11 mm/sec) and then remained stable until day 42 (0 .33 +/- 0.16 mm/sec). Two possible explanations can account for this a pparent discrepancy: first, dissociation between viscosity and velocit y due to the Fahraeus-Lindqvist effect (sigma effect); and secondly, i ncreased deformability of red blood cells leading to an increased red blood cell velocity despite an increased packed cell volume, It can be concluded that Daflon 500 me seems to have a beneficial haemorheologi cal effect, resolving the stasis with an increase in red blood cell ve locity. A concomitant increase in relative packed cell volume and red blood cell velocity after therapy suggests an improvement of the flexi bility of red blood cells.