Angiology

Recent histologic and immunocytochemical evidence of venous leg ulcers supports the hypothesis that lesions observed at different stages of chronic venous insufficiency may be associated with, and possibly caused by, an inflammatory process. Evidence has been obtained that venous valve deficiency may be associated with leukocyte infiltration into valve leaflets; therefore, it is hypothesized that an essential event in the inflammatory cascade is the enzymatic degradation of the valve leaflets and venous wall. The metalloproteinases (MMP) in veins exposed to elevated pressures up to 6 weeks were examined in a rat femoral fistula model with venous hypertension. Zymography shows increased activity of pro-MMP-2 at 3 and 6 weeks. MMP-2 and MMP-9 activity was predominantly observed at days 7 and 21 after creation of the fistula. The degree of extracellular matrix remodeling correlates with the morphological finding of macroscopic lesions. Therefore, the MMP-2 and MMP-9 activation is already present in veins days after exposure to elevated blood pressure and coincides with periods of early alterations in the valve morphology and early forms of reflux.

The mechanisms regulating varicose vein development and the subsequent skin sequelae seen in chronic venous disease (CVD) have been investigated recently. Despite the diversity of signs and symptoms associated with the disease, it seems likely that they are related to venous hypertension. Valvular incompetence is the most important cause of venous hypertension. Recent findings suggest that inflammatory processes are involved in the structural remodeling in venous valves and in the vein wall, leading to valvular incompetence and the development of varicose veins. This has been shown by Ono and colleagues, who found infiltration of valve leaflets and the venous wall by leukocytes (monocytes and tissue macrophages) in all valve specimens from patients with CVD and in none from controls. Further work by Takase and colleagues confirmed this hypothesis. Vein wall remodeling is likely to involve the complex interplay of a range of factors, including an altered ratio between metalloproteinases (MMPs) and their tissue inhibitors (TIMPs), and elevated levels of cytokines and growth factors favor an alteration of the extracellular matrix. Neutrophils and mast cells and their interaction with the venous endothelium are believed to play an important role in the initiation of the inflammatory response in CVD. The transmission of high venous pressures to the dermal microcirculation results in the stimulation of an inflammatory process in which cytokine and growth factor release leads to leukocyte migration into the interstitium and the initiation of further inflammatory events. This process is associated with the intense dermal fibrosis and tissue remodeling seen in chronic venous insufficiency. The many manifestations of the disease are frequently associated with symptoms usually ascribed to CVD. The proportion of patients with symptoms increases with increasing CEAP clinical classes, but the mechanisms underlying symptom appearance have not been elucidated. It has been postulated that it is related to the inflammatory cascade of events seen at all stages of CVD and in which the leukocyte and its interaction with the endothelium play a key role. It is increasingly believed that the emerging twin themes of disturbed venous flow patterns and chronic inflammation underlie and link all the manifestations of the disease. Among the many pathophysiologic mechanisms at work, the leukocyte-endothelium interactions seem to be important in many aspects of the disease and have been identified as a possible target for pharmacologic intervention. Pharmacologic agents that could attenuate various elements of the inflammatory cascade and inhibit the inflammatory process might offer a greater opportunity to prevent future morbidity. It seems reasonable to speculate that such treatment could reduce the risk of CVD progression if applied as soon as the first symptoms appear.

Chronic venous insufficiency is linked to venous hypertension and forces of shear stress on the endothelium. Venous hypertension depends upon two forces: the weight of a column of blood from the right atrium transmitted through the valveless vena cava and iliac veins to the femoral vein, and pressure generated by contracting skeletal muscles of the leg transmitted through failed perforating veins. When valve failure occurs in superficial axial veins and perforating veins, the venous pressure in the veins and venules of the skin and subcutaneous tissue is raised. The skin changes in chronic venous insufficiency are directly related to the severity of the venous hypertension. Also, pathologic changes in the valves are linked to venous hypertension and leukocyte infiltration and activation. It is hypothesized that acute venous pressure elevations cause a shift in the venous hemodynamics with changes in wall shear stress. This initiates the inflammatory cascade. Daflon 500 mg ameliorates the effects of chronic inflammation. In randomized trials, 60 days of therapy with Daflon at a dosage of 500 mg 2 tablets daily was effective, in addition to elastic compression, in accelerating venous ulcer healing. Because venous insufficiency is linked to venous hypertension and an inflammatory reaction, it appears that Daflon 500 mg 2 tablets daily shows a great potential for accomplishing blockade of the inflammatory cascade.

Patients suffering from any class of the Clinical, Etiological, Anatomical, Pathophysiological (CEAP) classification of chronic venous disease (CVD) may be symptomatic (C0s-C6s). Leg heaviness, discomfort, itching, cramps, pain, paresthesia, and edema (C3) are the most frequent manifestations of CVD and a major reason for medical consultation. Daflon 500 mg (micronized purified flavonoid fraction [MPFF]) is an effective treatment for symptoms and edema in CVD as demonstrated in several randomized controlled studies. A 2-month, double-blind study in 40 patients established the superiority of Daflon 500 mg over placebo with regard to symptoms and objective signs. This was confirmed in another double-blind, placebo-controlled trial (2 months’ treatment, 160 patients), and in the Reflux assEssment and quaLity of lIfe improvEment with micronized Flavonoids (RELIEF) study. The latter included 5,052 patients in 23 countries, using a visual analog scale for evaluating pain, leg heaviness, cramps, and a sensation of swelling. All symptoms showed significant and progressive improvement. The quality-of-life results (scores on the ChronIc Venous Insufficiency quality of life Questionnaire [CIVIQ]) paralleled those of symptoms. The decrease in the ankle and calf circumferences was significantly greater (p<0.001) in the group of patients treated with Daflon 500 mg in two studies, and correlated well with the improvement in the sensation of swelling (p<0.001). This was confirmed with more sophisticated measurement techniques as in the RELIEF study or in a trial assessing edema with an optoelectronic volumeter in 20 patients. A further double-blind, randomized, controlled study established a statistically significant difference in favor of Daflon 500 mg in comparison with diosmin, both on symptoms and edema. The therapeutic efficacy of Daflon 500 mg on CVD symptoms and edema has been demonstrated in double-blind, randomized, controlled studies. Further studies using a new approach may define the most precise and validated methodology for application in future research in phlebology.

The objective of this study was to assess the effect of oral treatment with Daflon 500 mg (micronized purified flavonoid fraction [MPFF]) on leg ulcer healing. This study was conducted as a meta-analysis of randomized prospective studies using Daflon 500 mg as an adjunct to conventional treatment. Medical literature databases and the manufacturer’s records were searched for relevant clinical trials. Five prospective, randomized, controlled studies in which 723 patients with venous ulcers were treated between 1996 and 2001 were identified. Conventional treatment (compression and local care) in addition to Daflon 500 mg 2 tablets daily was compared with conventional treatment plus placebo in two studies (n=309), or with conventional treatment alone in three studies (n=414). The primary end point was complete ulcer healing at 6 months. The results are expressed as a reduction in the relative risk (RRR) of healing with 95% confidence intervals (CI). Since, in the present case, the desired treatment effect is increased ulcer healing, RRR should be positive to indicate a benefit of adjunctive Daflon 500 mg over conventional therapy alone. Type 1 error was set at 5%. At 6 months, the chance of ulcer healing was 32% better in patients treated with adjunctive Daflon 500 mg than in those managed by conventional therapy alone (RRR, 32%; 95% CI, 3% to 70%). This difference was present from month 2 (RRR, 44%; 95% CI, 7% to 94%), and was associated with a shorter time to healing (16 weeks vs 21 weeks; p=0.0034). The benefit of Daflon 500 mg was found in the subgroup of ulcers between 5 and 10 cm2 in area (RRR, 40%; 95% CI, 6% to 87%), as well as in patients with ulcers of 6 to 12 months’ duration (RRR, 44%; 95% CI, 6% to 97%). These results confirm that venous ulcer healing is accelerated by Daflon 500 mg treatment. Daflon 500 mg might be a useful adjunct to conventional therapy in large and longstanding ulcers that might be expected to heal slowly.