CARDIOVASCULAR JOURNAL OF AFRICA • Volume 33, No 2, March/April 2022 AFRICA 45 Bacterial colonisation is present in approximately 80 to 100% of leg ulcers.7,8 Several studies have demonstrated that increased bacterial bioburden prolongs the wound-healing process.8 Bacterial diversity and density are critical factors for prolonged healing processes.9,10 In the presence of infected ulcers, bacteria invade living dermal and subdermal tissues, and the clinical manifestations include worsening pain, warmth, swelling and erythema of the skin around the ulcer, which hamper wound healing. Wound infection prolongs the duration of response to chronic ulcers and delays collagen synthesis, slowing the epithelialisation process and secreting proteases.9 Wound culture is the mainstay of treatment for chronic wounds.11 The most common culprits of chronic leg ulcers are Staphylococcus aureus (S aureus), Pseudomonas aeruginosa (P aeruginosa), Escherichia coli (E coli), Proteus mirabilis (P mirabilis) and Enterobacter cloacae (E cloacae).12 In recent years, however, the spectrum of micro-organisms most frequently isolated has expanded. A few years ago, researchers paid particular interest to gram-positive micro-organisms such as S aureus. However, gram-negative bacteria are more frequently being isolated worldwide and have become more clinically significant.13 Although S aureus is the most common pathogen in leg ulcers, recent studies have demonstrated higher rates of anaerobic and gram-negative bacilli in clinically infected leg ulcers than in those without infection.14,15 The majority of bacteria are resistant to a variety of antibiotics, such as doxycycline and penicillin, and more than half of cases have multidrug resistance (MDR).16,17 Vacuum-assisted closure (VAC) therapy is used for chronic wounds to stimulate rapid wound healing. The therapy consists of an open-cell polyurethane sponge sealed by an adhesive drape 400 to 600 microns in size and 0.703 to 0.0228 kgf/cm3 compression with an open-cell structured network. An open-cell, soft connection port is placed, and the other end of the port is mounted on the device, producing negative pressure (Fig. 1). The VAC system provides sub-atmospheric pressure for physical contraction by removing toxins, excessive interstitial fluid and cell debris from the wound bed. Macrostrain is the visible change that occurs when negative pressure contracts the foam that is in direct contact with the wound bed, drawing the wound edges together (Fig. 2).18 Due to the macrostrain effect, wound edges are diminished, and exudate and infectious material are removed, leading to reduced bacterial bioburden and tissue oedema. The VAC drape is an adhesive layer, ensuring a closed, moist, wound-healing environment and preventing external contamination. In recent years, VAC therapy using local negative pressure has been used as a non-invasive adjunct in the field of plastic and reconstructive surgery. The clinical efficacy of VAC therapy has been shown in the treatment of venous leg ulcers.19 In our study on the healing of infected chronic venous stasis leg ulcers in patients with severe PTS after DVT, we aimed to investigate the effect of VAC treatment, to elucidate its mechanism of action and to determine whether it could be used for these patients with limited treatment options. Methods Patients with chronic venous stasis ulcers who were admitted to the cardiovascular surgery clinic between January 2016 and January 2019 and diagnosed with severe PTS were included in this study. PTS Villata–Prandoni severity rating scoring was performed for all patients. Twelve patients with a Villata– Prandoni score > 14 (mean age: 50.2 years; range 38–71 years) were considered to have severe PTS. VAC treatment was applied to the 12 patients with severe PTS and 14 venous stasis ulcers. Written informed consent was obtained from each patient. The inclusion criteria were as follows: previous diagnosis of DVT, severe PTS, chronic venous insufficiency, a venous ulcer that did not heal despite venous correction procedures, and clinical signs and symptoms of infection with microorganism growth in the pre-procedural wound culture. The exclusion criteria were as follows: acute DVT, peripheral arterial insufficiency [ankle–brachial index (ABI) < 0.8], anti-aggregant and anticoagulant therapy, visible vascular structures, untreated osteomyelitis, necrotic wounds with severe scarring, and decision to undergo venous correction and compression therapy first for ulcer healing. The study protocol was approved by the ethics committee of the Republic of Turkey, Ministry of Health, Turkish Medicines and Medical Devices Agency, Research & Development Department (65355327-604.01.02-E.134, Decree No. 26). The study was conducted in accordance with the principles of the Declaration of Helsinki. Fig. 1. VAC system. 1 shows the collection reservoir; 2 shows pressure and mode control device; 3 shows polyurethane sponge and drape; 4 shows the connection port. Fig. 2. Macrostrain effect of VAC system. 1 2 3 4
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