Reduction of lower-limb edema in patients with chronic venous disease by micronized purified flavonoid fraction: a systematic literature review and meta-analysis

INTRODUCTION

The prevalence of lower limb edema is high among patients with chronic venous disease (CVD). Several clinical studies with various designs have assessed the effect of micronized purified flavonoid fraction (MPFF) on edema. The aim of this work was to provide a comprehensive and accurate evaluation of the reduction in ankle and calf circumference as an indicator of lower limb edema reduction in patients with CVD treated with MPFF by combining studies that use different designs in a single group meta-analysis.

EVIDENCE ACQUISITION

We conducted a systematic literature review in April 2022 based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) criteria to identify prospective studies investigating the effect of oral MPFF treatment 1000 mg/day on ankle and calf circumference in patients with CVD. Studies with population including at least one patient with an ulcer were excluded. All prospective studies irrespectively of design (i.e., interventional and non-interventional studies, randomized controlled trials (RCTs), non-randomized studies, studies without a control or reference treatment) were eligible. The Medline, Embase and Cochrane databases were searched. Endpoints were ankle and calf circumference measurements and their overall mean change from baseline estimated with random-effects meta-analysis methods. The evaluation criterion feeling of swelling was also analyzed as a standardized mean change (SMC) with 95% confidence intervals after combination of quantitative scales.

EVIDENCE SYNTHESIS

Among 861 articles identified, eight studies (five RCTs including one placebo-controlled, three non-comparative studies) met the criteria. The overall population consisted of 1635 patients, predominantly female (89% ranging from 64% to 94%) with a mean age of 47 years ranging from 41 to 48 years. Mean reduction in ankle circumference was 6.0 mm (95%CI: 3.6 to 8.4; P<0.001) and 7.0 mm (95%CI: 0.9 to 13.1; P=0.024) after two and at least six months of treatment respectively. The results were similar when considering the study type RCTs and non-RCTs. Mean reduction in calf circumference was 5.7 mm (95%CI: 2.8 to 8.6; P<0.001) and 6.7 mm (95%CI: 5.2 to 8.1; P<0.001), at two months and at the last post-baseline evaluation respectively. Heterogeneity among studies was statistically significant (degree of consistency I2=93.5%; P<0.001 and I2=81.1%, P<0.01 for ankle and calf circumference, respectively). In the three studies reporting the effect on feeling of swelling a significant standardized mean change (SMC) reduction of 2.2 (95%CI: 0.2 to 4.2; P=0.028) on a quantitative scale was observed after two months of treatment with MPFF.

CONCLUSIONS

MPFF appeared to be effective in reducing ankle and calf circumference as well as feeling of swelling irrespective of study design. The circumference reduction is present at short and long term, suggesting that benefit occurs early and is maintained overtime. Despite the observed heterogeneity among included studies, this meta-analysis supports the significant therapeutic efficacy of MPFF in reducing lower-limb edema in patients with CVD. The complete video presentation of the work is available online at www.minervamedica.it (Supplementary Digital Material 1: Supplementary Video 1, 5 min, 192 MB).

The effect of purified micronized flavonoid fraction on the healing of anastomoses in the colon in rats

PURPOSE

Anastomotic leakage of colonic and rectal anastomoses is a major complication after large intestine surgery. Many factors influence the healing of colon anastomoses. Flavonoids have been recognized for centuries as physiologically active constituents that are used to treat human diseases. We studied the effects of a clinically used, micronized, purified flavonoid fraction on the healing of colonic anastomosis in rats.

METHODS

Male Sprague-Dawley rats were used. The flavonoid group of rats received 100 mg/kg per day of Daflon for 14 days until surgery. Thereafter, a resection and anastomosis were performed. The bursting pressure of the anastomoses and the hydroxyproline levels of the perianastomotic tissue were determined to evaluate the healing on the third and seventh days of surgery for both flavonoid and control groups.

RESULTS

The bursting pressure of the flavonoid group was higher on the seventh day. The hydroxyproline levels of the flavonoid group were significantly higher than in the control group on both the third and seventh days after surgery.

CONCLUSIONS

Although the micronized purified flavonoid fraction has some inhibitory properties on the healing of the anastomosis, its net effect was to obtain a better anastomotic healing of the colon in rats.

State-of-the-art treatment of chronic venous disease

The article summarizes the epidemiology, classification and differential diagnosis of venous disease and its complications. Theories of venous ulceration and diagnostic and treatment modalities are reviewed.

Dorsal pedal venous oximetry as an outcome index of lower extremity revascularizations

Dorsal pedal venous blood gas analysis was performed in 24 patients with arterial occlusive disease requiring revascularizations of the lower extremities. After the reconstructive surgical procedure, measurements were repeated. It has been observed that this method is useful before surgery since it proves the severity of tissue hypoxia due to perfusion impairment of the foot. Postoperative measurements have detected the effectiveness of the vascular restorations. The results of the trial showed a mean increase in partial pressure of venous blood oxygen (PVO2) and pH of 30.3% and 13.7% (p<0.05), respectively and a mean decrease in partial pressure of arterial carbon dioxide (PCO2) of 12.9% (p<0.05) between initial and postsurgical measurements in involved legs. In the healthy, unoperated on side, there was no significant (p>0.05) change in response to arterial reconstructions. Symptoms decreased markedly in direct proportion to the increase in dorsal pedal venous PO2 induced by changes in blood flow. This method can be reliably used for assessing the treatment to ensure adequate oxygen delivery to the foot as a result of improved pedal perfusion.