A randomized, double-blind, placebo-controlled, clinical study on the efficacy and safety of calcium dobesilate in the treatment of chronic venous insufficiency

Study protocol for assessment of the efficacy of calcium dobesilate versus placebo on SARS-CoV-2 viral load in outpatients with COVID-19 (CADOVID study): a randomised, placebo-controlled, double-blind, monocentric phase II trial

INTRODUCTION

SARS-CoV-2 mainly infects respiratory endothelial cells, which is facilitated through its spike protein binding to heparan sulphate. Calcium dobesilate (CaD) is a well-established, widely available vasoactive and angioprotective drug interacting with heparan sulphate, with the potential to interfere with the uptake of SARS-CoV-2 by epithelial cells. The CADOVID trial aims to evaluate the efficacy and safety of CaD in reducing the SARS-CoV-2 viral load in non-hospitalised adult patients diagnosed with COVID-19, confirmed by a positive SARS-CoV-2 PCR, including its efficacy to reduce the impact of persistent COVID-19 symptoms.

METHODS AND ANALYSIS

This is a randomised, placebo-controlled, double-blind, monocentric phase II trial. Enrolment began in July 2022. A total of 74 adult patients will be randomly allocated to the CaD arm or the placebo group with a 1:1 ratio, respectively. Participants in the intervention arm will receive two capsules of CaD 500 mg two times per day and the placebo arm will receive two matching capsules of mannitol 312.5 mg two times per day, with a treatment period of 7 days for both arms, followed by a 77-day observational period without treatment administration. Participants will be asked to complete secured online questionnaires using their personal smartphone or other electronic device. These include a COVID-19 questionnaire (assessing symptoms, temperature measurement, reporting of concomitant medication and adverse events), a COVID-19 persistent symptoms' questionnaire and the Short Form 12-Item (SF-12) survey. SARS-CoV-2 PCR testing will be performed on nasopharyngeal swabs collected on days 1, 4, 8 and 21. The primary endpoint is the reduction from baseline of SARS-CoV-2 viral load determined by RT-PCR at day 4.

ETHICS AND DISSEMINATION

This trial has received approval by the Geneva Regional Research Ethics Committee (2022-00613) and Swissmedic (701339). Dissemination of results will be through presentations at scientific conferences and publication in scientific journals.

TRIAL REGISTRATION NUMBER

NCT05305508; Clinicaltrials.gov; Swiss National Clinical Portal Registry (SNCTP 000004938).

Brazilian guidelines on chronic venous disease of the Brazilian Society of Angiology and Vascular Surgery

The Brazilian Society of Angiology and Vascular Surgery has set up a committee to provide new evidence-based recommendations for patient care associated with chronic venous insufficiency. Topics were divided in five groups: 1. Classification, 2. Diagnosis, 3. Conservative or non-invasive treatment, 4. Invasive treatment and 5. Treatment of small vessels. This last series is closely related to the activities of Brazilian angiologists and vascular surgeons, who are heavily involved in the treatment of small superficial veins. These guidelines are intended to assist in clinical decision-making for attending physicians and health managers. The decision to follow a guideline recommendation should be made by the responsible physician on a case-by-case basis taking into account the patient's specific condition, as well as local resources, regulations, laws, and clinical practice recommendations.

Quality of Life in Chronic Venous Disease: Bridging the Gap Between Patients and Physicians

Chronic venous disease (CVD) has a negative impact on patients' quality of life (QoL). This was demonstrated in the recent Patient Journey on CVD study, which examined QoL in patients with early- and advanced-stage CVD (Clinical, Etiological, Anatomical and Pathophysiological classification C0 to C4), and the gaps between the way in which physicians and patients viewed the impact of CVD on QoL. The study was conducted in five countries (Brazil, China, Czech Republic, Italy and Russia) and included 100 patients with CVD and 60 CVD specialists. Patients completed the 14-item Chronic Venous Insufficiency Questionnaire (CIVIQ-14) to assess their QoL, and all patients and physicians were questioned during a 60-minute qualitative structured interview, focusing on four key dimensions-physical symptoms, aesthetics/appearance, emotional impact and impact on relationships. The study found that physicians tended to focus more on physical symptoms than on other impacts of CVD and rarely measured QoL in clinical practice. Patients were significantly less satisfied with the management of their QoL than physicians perceived them to be. About 25% of patients with CVD reported disturbed sleep, but physicians did not routinely ask them how CVD affected their sleep. These data reinforce the importance of physicians obtaining information about the impact of CVD on all aspects of the patient's life, including sleep and QoL. Evidence from randomised controlled trials and real-world studies demonstrates that some veno-active drugs, particularly micronised purified flavonoid fraction, can positively impact QoL in patients with CVD.

Calcium dobesilate reduces SARS-CoV-2 entry into endothelial cells by inhibiting virus binding to heparan sulfate

Recent reports demonstrate that SARS-CoV-2 utilizes cell surface heparan sulfate as an attachment factor to facilitate the initial interaction with host cells. Heparan sulfate interacts with the receptor binding domain of SARS-CoV-2 spike glycoprotein, and blocking this interaction can decrease cell infection. We and others reported recently that the family of compounds of 2,5-dihydroxyphenylic acid interferes with the binding of the positively charged groove in growth factor molecules to negatively charged cell surface heparan sulfate. We hypothesized that Calcium Dobesilate (CaD)-calcium salt of 2,5-dihydroxyphenylic acid-may also interfere with the binding of SARS-CoV-2 spike protein to heparan sulfate. Using lentiviral SARS-CoV-2 spike protein pseudotyped particles we show that CaD could significantly reduce pseudovirus uptake into endothelial cells. On the contrary, CaD did not affect cell infection with VSVG-expressing lentivirus. CaD could also prevent retention of SARS-CoV-2 spike protein in ex vivo perfused mouse kidney. Using microfluidic culture of endothelial cells under flow, we show that CaD prevents spike protein interaction with heparan sulfate glycocalyx. Since CaD has no adverse side effects and is approved in humans for other medical indications, our findings can rapidly translate into clinical studies.

Systematic literature review and network Meta-analysis of sulodexide and other drugs in chronic venous disease

OBJECTIVE

To assess the clinical efficacy of sulodexide, including a comparison with venoactive drugs (VAD) (micronized purified flavonoid fraction, MPFF; hydroxy-ethyl-rutosides, HR; calcium dobesilate;Ruscus extract combined with hesperidin methyl chalcone and vitamin C, Ruscus+HMC+VitC; horse chestnut seed extract, HCSE) and pentoxifylline in patients with chronic venous disease.

METHODS

We performed a literature search in MEDLINE, Embase, and Cochrane Library for randomized controlled trials (RCTs) and observational studies. Proportion of patients with complete venous ulcer healing was the primary outcome and lower leg volume, foot volume, ankle circumference and symptoms were the secondary outcomes. Bayesian network meta-analysis (NMA) was perfomed with random effects models using only RCTs. A meta-analysis of observational studies was performed for sulodexide because no RCT could be included in NMA for symptoms or signs.

RESULTS

Forty-five RCTs and eighteen observational studies were identified. Sulodexide was included only in a single NMA for the proportion of patients with complete ulcer healing and it showed to have the highest probability of being the best treatment (48%) compared with pentoxifylline (37%) and MPFF (16%). MPFF was the most effective treatment in reducing lower leg volume, CIVIQ-20 score and pain VAS scale while calcium dobesilate and Ruscus+HMC+VitC were the most effective in reducing foot volume and ankle circumference respectively.Meta-analyses of observational studies for sulodexide showed that it improves significantly the scoring of pain, feeling of swelling, heaviness and parasthesiae measured by Likert scales.

CONCLUSIONS

Sulodexide is at least as effective as pentoxifylline and more effective than MPFF in improving the rate of ulcer healing in patients with CVD. VADs are effective in improving venous symptoms and signs, as was also shown by sulodexide in the meta-analysis of observational studies. The relative effectiveness of sulodexide and VADs needs to be evaluated by an RCT in order to better inform clinical practice.

Management of Lower Extremity Pain from Chronic Venous Insufficiency: A Comprehensive Review

PURPOSE OF REVIEW

Chronic venous insufficiency is found to some extent in a large proportion of the world's population, especially in the elderly and obese. Despite its prevalence, little research has been pursued into this pathology when compared to similarly common conditions. Pain is often the presenting symptom of chronic venous insufficiency and has significant deleterious effects on quality of life. This manuscript will describe the development of pain in chronic venous insufficiency, and will also review both traditional methods of pain management and novel advances in both medical and surgical therapy for this disease.

RECENT FINDINGS

Pain in chronic venous insufficiency is a common complication which remains poorly correlated in recent studies with the clinically observable extent of disease. Although lifestyle modification remains the foundation of treatment for pain associated with chronic venous sufficiency, compression devices and various pharmacologic agents have emerged as safe and effective treatments for pain in these patients. In patients for whom these measures are insufficient, recently developed minimally invasive vascular surgical techniques have been shown to reduce postsurgical complications and recovery time, although additional research is necessary to characterize long-term outcomes of these procedures. This review discusses the latest findings concerning the pathophysiology of pain in chronic venous insufficiency, conservative and medical management, and surgical strategies for pain relief, including minimally invasive treatment strategies.

Phlebotonics for venous insufficiency

BACKGROUND

Chronic venous insufficiency (CVI) is a condition in which veins are unable to transport blood unidirectionally towards the heart. CVI usually occurs in the lower limbs. It might result in considerable discomfort, with symptoms such as pain, itchiness and tiredness in the legs. Patients with CVI may also experience swelling and ulcers. Phlebotonics are a class of drugs often used to treat CVI. This is the second update of a review first published in 2005.

OBJECTIVES

To assess the efficacy and safety of phlebotonics administered orally or topically for treatment of signs and symptoms of lower extremity CVI.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, and CINAHL databases and the World Health Organization International Clinical Trials Registry Platform and Clinicaltrials.gov trials register up to 12 November 2019. We searched the reference lists of the articles retrieved by electronic searches for additional citations. We also contacted authors of unpublished studies.

SELECTION CRITERIA

We included randomised, double-blind, placebo-controlled trials (RCTs) assessing the efficacy of phlebotonics (rutosides, hidrosmine, diosmine, calcium dobesilate, chromocarbe, Centella asiatica, disodium flavodate, French maritime pine bark extract, grape seed extract and aminaftone) in patients with CVI at any stage of the disease.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed the quality of included RCTs. We estimated the effects of treatment by using risk ratios (RRs), mean differences (MDs) and standardized mean differences (SMDs), according to the outcome assessed. We calculated 95% confidence intervals (CIs) and percentage of heterogeneity (I²). Outcomes of interest were oedema, quality of life (QoL), assessment of CVI and adverse events. We used GRADE criteria to assess the certainty of the evidence.

MAIN RESULTS

We identified three new studies for this update. In total, 69 RCTs of oral phlebotonics were included, but only 56 studies (7690 participants, mean age 50 years) provided quantifiable data for the efficacy analysis. These studies used different phlebotonics (28 on rutosides, 11 on hidrosmine and diosmine, 10 on calcium dobesilate, two on Centella asiatica, two on aminaftone, two on French maritime pine bark extract and one on grape seed extract). No studies evaluating topical phlebotonics, chromocarbe, naftazone or disodium flavodate fulfilled the inclusion criteria. Moderate-certainty evidence suggests that phlebotonics probably reduce oedema slightly in the lower legs, compared with placebo (RR 0.70, 95% CI 0.63 to 0.78; 13 studies; 1245 participants); and probably reduce ankle circumference (MD -4.27 mm, 95% CI -5.61 to -2.93 mm; 15 studies; 2010 participants). Moderate-certainty evidence shows that phlebotonics probably make little or no difference in QoL compared with placebo (SMD -0.06, 95% CI -0.22 to 0.10; five studies; 1639 participants); and similarly, may have little or no effect on ulcer healing (RR 0.94, 95% CI 0.79 to 1.13; six studies; 461 participants; low-certainty evidence). Thirty-seven studies reported on adverse events. Pooled data suggest that phlebotonics probably increase adverse events slightly, compared to placebo (RR 1.14, 95% CI 1.02 to 1.27; 37 studies; 5789 participants; moderate-certainty evidence). Gastrointestinal disorders were the most frequently reported adverse events. We downgraded our certainty in the evidence from 'high' to 'moderate' because of risk of bias concerns, and further to 'low' because of imprecision.

AUTHORS' CONCLUSIONS

There is moderate-certainty evidence that phlebotonics probably reduce oedema slightly, compared to placebo; moderate-certainty evidence of little or no difference in QoL; and low-certainty evidence that these drugs do not influence ulcer healing. Moderate-certainty evidence suggests that phlebotonics are probably associated with a higher risk of adverse events than placebo. Studies included in this systematic review provided only short-term safety data; therefore, the medium- and long-term safety of phlebotonics could not be estimated. Findings for specific groups of phlebotonics are limited due to small study numbers and heterogeneous results. Additional high-quality RCTs focusing on clinically important outcomes are needed to improve the evidence base.

[Duration of treatment with phlebotonics in patients with chronic venous disease]

Lower extremity chronic venous disease is a highly prevalent vascular pathology. Progression of the disease exerts a negative impact on the patients' quality of life and imposes a large economic burden on the healthcare systems. Conventional methods of conservative treatment of chronic venous disease include wearing compression knitwear and pharmacological therapy. Although highly effective, compression therapy appears to be associated with lower compliance due to difficulties putting on and taking off the compression stockings. Therefore, the majority of patients prefer pharmacological therapy with phlebotonic drugs. There are many phlebotropic agents possessing particular indications and recommendations regarding the duration of administration. This article presents a review of the available literature addressing the problems related to prescription of pharmacotherapy to patients with lower limb chronic venous disease, also describing the results of published clinical studies evaluating efficacy and safety of phlebotropic drugs, as well as those concerning the duration of the course administration of drugs depending on the severity of the disease, invasive nature of a surgical intervention performed, or sclerotherapy. Besides, analysed is the role of phleboactive agents in correction of pathophysiological mechanisms of the development and progression of venous disease. This is followed by a review of clinical trials studying the influence of phlebotonics on such links of pathogenesis as leukocyte activation, vein-specific inflammation, endothelial dysfunction, and activation of proteolytic enzymes promoting destruction of the extracellular matrix. Based on the above data, proposed herein are appropriate approaches to determining the duration of the courses of phlebotropic therapy with due regard for the patients' status, underlying once again the importance and necessity of a personalized approach to selection of the optimal duration of venotonic therapy.

Does Calcium Dobesilate Have Therapeutic Effect on Gentamicin-induced Cochlear Nerve Ototoxicity? An Experimental Study

HYPOTHESIS

The ototoxic effects of aminoglycosides are well known. Gentamicin carries a substantial risk of hearing loss. Gentamicin is widely used to combat life-threatening infections, despite its ototoxic effects. Calcium dobesilate is a pharmacologically active agent used to treat many disorders due to its vasoprotective and antioxidant effects. We investigated the therapeutic role of calcium dobesilate against gentamicin-induced cochlear nerve ototoxicity in an animal model.

METHODS

Thirty-two Sprague Dawley rats were divided into four groups: Gentamicin, Gentamicin + Calcium Dobesilate, Calcium Dobesilate, and Control. Preoperative and postoperative hearing thresholds were determined using auditory brainstem response thresholds with click and 16-kHz tone-burst stimuli. Histological analysis of the tympanic bulla specimens was performed under light and transmission electron microscopy. The histological findings were subjected to semiquantitative grading, of which the results were compared between the groups.

RESULTS

Gentamicin + Calcium Dobesilate group had, on average, 27 dB better click-evoked hearing than Gentamicin group (p < 0.01), whereas the difference was not significant with 16-kHz tone-burst stimuli (p > 0.01). Histologically examining the Control and Calcium Dobesilate groups revealed normal ultrastructural appearances. The Gentamicin group showed the most severe histological alterations including myelin destruction, total axonal degeneration, and edema. The histological evidence of damage was significantly reduced in the Gentamicin + Calcium Dobesilate group compared with the Gentamicin group.

CONCLUSION

Adding oral calcium dobesilate to systemic gentamicin was demonstrated to exert beneficial effects on click-evoked hearing thresholds, as supported by the histological findings.

Calcium dobesilate (Doxium®) in bone marrow edema syndrome and suspected osteonecrosis of the hip joint - A case series

Osteonecrosis of the femoral head is a disease that leads to gradual degeneration of the hip joint causing immobility and a devastating impairment of quality of life. Early stage disease is characterised by a bone marrow edema of the proximal femur, a sight it shares with bone marrow edema syndrome. Although total hip arthroplasty offers quick symptom relief and functionally appealing results the treatment remains challenging, with its particularly young patients and considering limited non-invasive treatment options. We treated 6 patients with bone marrow edema in MRI and suspected osteonecrosis of the hip joint with calcium dobesilate, a vasoactive agent used in the treatment of diabetic retinopathy. We could demonstrate rapid symptom relief and concomitant disease remission on control MRI in early stage disease without any adverse events. Patients at advanced stages benefited in terms of pain reduction, but the treatment failed to halt disease progression. To the best of our knowledge, this is the first report of the therapeutic administration of calcium dobesilate in patients with bone marrow edema syndrome or osteonecrosis of the hip joint.

Venoprotective drugs in pigmented purpuric dermatoses: A case report

Pigmented purpuric dermatoses (PPD) or capillaritis represent a benign condition, presenting with extravasation of erythrocytes in the skin and prominent hemosiderin deposition. The eruption runs a chronic relapsing course and is resistant to therapy. Capillary fragility, cellular immunity, and microvascular inflammation play important roles in the pathogenesis of PPD. Bioflavonoids, currently used as venoprotective agents for the management of chronic venous insufficiency, have been shown to reduce capillary fragility and permeability by inhibiting endothelial cell activation and modulating the leukocyte-endothelium interaction. We report a case of PPD with dramatic improvement consequent to a therapy with a fixed dose combination containing flavonoids like diosmin, hesperidin, and Euphorbia prostata extract along with calcium dobesilate.

Systemic therapies for leg ulcers

Successful management of patients with leg ulcers requires identification of the underlying etiology, with subsequent initiation of causal treatment, if feasible. Supplementary measures of first choice include stage-adjusted wound treatment, usually combined with compression therapy. The significance of systemic drugs has been the subject of controversial debate, depending on the underlying cause of the condition. The present review article is therefore meant to highlight current aspects of systemic drug therapies for the treatment of leg ulcers associated with chronic venous insufficiency, peripheral arterial disease, livedoid vasculopathy, vasculitis, necrobiosis lipoidica, calciphylaxis and pyoderma gangrenosum. In summary, the majority of therapeutic options presented herein are used off-label. While systemic drugs are promising options for the more common types of wounds such as venous, mixed or arterial leg ulcers, they do not represent the current standard of treatment. By contrast, systemic agents play a key role in the management of many of the other disorders presented herein. These agents primarily include immunomodulatory and rheological drugs used to expedite wound healing.

Calcium Dobesilate and Micro-vascular diseases

Micro-vascular diseases and its associated complications continue to be a significant health problem worldwide. Vascular lesions from microvascular involvement lead to impaired blood flow and contribute to damage and dysfunction of one or more target organs, that is, the heart, kidneys, eyes, and nervous system. Calcium Dobesilate Drug (CAD) is an established vasoactive and angioprotective drug that has shown a unique, multitarget mode of action in several experimental studies and in different animal models of diabetic microvascular complications. CAD has been widely used as an antioxidant and a vascular protective agent. At present, the application of Calcium Dobesilate is mainly related to Micro-vascular damage-related diseases, such as diabetic retinopathy (DR) and diabetic nephropathy (DN), and it is found to significantly improve the related symptoms. Its beneficial effects make it an attractive therapeutic compound especially in the early stages of these diseases. Scholars at home and abroad have studied the effectiveness, safety, and mechanisms of the related diseases, furthermore, the subjects involved patients and animal models, they have found some new clinical effects of this medicine. This paper makes a brief summary of a research progress of clinical application about Vascular injury related diseases and other aspects.

Efficacy of subcutaneous lidocaine injection in venous insufficiency: a prospective, randomized, controlled study, and new treatment protocol

[Purpose] The purpose of this study was to evaluate the efficacy of subcutaneous injection with lidocaine in patients with chronic venous insufficiency in the early stage. [Subjects and Methods] Patients (n=50) randomized to the treatment group received subcutaneous injections from a mixture of physiological saline sterile solution and lidocaine once a week to both legs below the knee for 5 sessions. Patients in the treatment group were also given ankle pumping exercises and compression stockings throughout the treatment. Patients randomized to the control group (n=50) received only ankle pumping exercises and compression stockings. Patients were evaluated using the visual analog scale (VAS) for pain and Chronic Venous Disease Quality of life Questionnaire (CIVIQ-20) for quality-of-life at months 1, 3, 6, at the end of month 12, and at the end of the injection treatment for 5 sessions. [Results] CIVIQ-20 and VAS results were significantly lower in the treatment group, than in the control group at months 1, 3 and 6. However, CIVIQ-20 and VAS results were not significantly different, compared with the pre-operative period at month 12. [Conclusion] We observed that 5-week subcutaneous lidocaine injection treatment was effective in patients who do not respond to oral medical treatment or in whom surgery is not considered.