M. Vimeux

Evaluation of haemorheological and microcirculatory disturbances in chronic venous insufficiency: activity of Daflon 500 mg.

The use of Daflon 500 mg has been shown to improve venous tone, microvascular permeability, lymphatic activity, and microcirculatory nutritive flow. This study aimed to assess the effects of Daflon 500 mg at a daily dose of 2 tab/day on microcirculatory, haemorheologic parameters, white blood cell counts and neutrophil activation in patients suffering from chronic venous insufficiency (CVI). This was a single-centre double-blind placebo-controlled study comparing two parallel groups of CVI patients who were treated for 2 months with Daflon 500 mg (n = 39) or placebo (n = 38). Evaluations were performed before treatment (D0) and at the end of treatment (D60). Blood samples were drawn from a foot vein before and at the end of a 15-min period of venous hypertension provoked by a cuff inflated to 100 mm Hg. Red blood cell (RBC) deformability was determined by the initial flow rate filtration technique using a Hanss haemorheometer. RBC aggregation was evaluated by a Myrenne aggregometer based on analysis of transmitted light through a blood sample during flow. RBC disaggregation was evaluated by Sefam erythro-aggregometer based on analysis of the backscattered light through a blood sample in a Couette flow. Microcirculatory parameters were assessed by means of laser Doppler fluxmetry and transcutaneous oxymetry measurements and consisted of continuous records of blood flux (BF) and TcPO2 before and during 15 min of venous hypertension. Results are expressed as absolute values at baseline (before stasis) and at the end of stasis, before and after 2 months of treatment. Univariate analysis showed a significant reduction of the stasis-induced RBC aggregation index (Daflon 500 mg: -0.07+/-0.20; placebo: 0.04+/-0.18; mean +/- SD; p = 0.03). Multivariate analysis identified a subset of 5 variables (RBC aggregation, RBC count, microcirculatory BF, amplitude and frequency of vasomotion) that produced a good discrimination model between the two treatments. Linear combination of these 5 variables in 48 patients with complete data showed a significant difference (p < 0.001) between the groups. These changes suggest a protective effect of Daflon 500 mg on the deleterious influence of stasis on microcirculatory (BF) and hemorheologic (RBC aggregation) parameters in CVI patients in comparison to patients receiving placebo.

Hemorheological factors in the pathophysiology of venous disease

In this study the essential microrheological parameters (hematocrit, plasma viscosity, fibrinogen, erythrocyte aggregation and deformability) were tested on 20 control subjects and 20 patients having varicose veins in the legs

Measurements of Transcutaneous Oxygen Pressure and Changes in Blood Rheology as Markers of Prognosis of Critically Ischemic Limb in Diabetes Mellitus Patients

The aims of this study were to compare variations of the transcutaneous oxygen pressure (TcPO2) and blood rheology in diabetic patients. Diabetic patients with critical limb ischemia were compared with those who were either asymptomatic or had mild peripheral vascular disease (PVD). The results showed a significant decrease in TcPO2 in patients with critical limb ischemia. Low shear rate blood viscosity, red blood cell (RBC) aggregation, plasma viscosity, and fibrinogen level were significantly higher in the group with critical severe limb ischemia. The group with critical limb ischemia was subdivided on the basis of clinical outcomes after 1 year and the prognostic values of these measurements examined. A TcPO2 value of 10 mm Hg was associated with a positive predictive value of 94%. RBC aggregation index and fibrinogen levels offered positive predictive values of 89% and 88%, respectively, when cut off values were derived from means + 1 SD of same parameters in patients with asymptomatic or mild PVD. TcPO2 is useful to follow the deterioration of diabetics with critical limb ischemia.

The Effects of Cyclo 3 Fort Treatment on Hemorheological Disturbances During a Provoked Venous Stasis in Patients with Chronic Venous Insufficiency

The presence of multiple microcirculatory alterations has already been pointed-out in chronic venous insufficiency “CVI” (1–6). In previous studies, we reported impairments in RBC rheologic behaviour which appear in the early uncomplicated stages of this disease (7–8). These impairements were shown, on the other hand, to be exaggerated when using a venous stasis stimulus in patients.

Effects of buflomedil on microvascular disorders in diabetic patients

The aim of this work was to evaluate the effect of buflomedil on hemorheologic, hemodynamic and microcirculatory properties in diabetic patients. Patients were 20 noninsulin-dependent diabetics with distal arteriopathy characterized by chronic hypoxia (transcutaneous oxygen pressure = 25.2 +/- 4.8 mm Hg). They were randomly assigned to two groups for a double-blind study versus placebo. The treatment consisted of a 4-hour intravenous perfusion of 400 mg of buflomedil or placebo as a daily dose during 7 days. Results showed significant improvements in hemodynamic parameters such as post-occlusive peak flow and time to peak flow at the end of buflomedil treatment. In the same manner, the transcutaneous oxygen pressure was found to be significantly increased after buflomedil treatment, whereas there was no modification by placebo. Indeed, red cell aggregation was significantly less important as a result of buflomedil treatment whilst red cell deformability was found to be significantly increased. These hemorheological improvements make the blood flow redistribution through the microcirculatory network easier and lead ultimately to better tissue oxygenation.