VAC therapy to promote wound healing after surgical revascularisation for critical lower limb ischaemia

Negative-Pressure Wound Therapy: What We Know and What We Need to Know

Negative-pressure wound therapy (NPWT) promotes wound healing by applying negative pressure to the wound surface. A quarter of a century after its introduction, NPWT has been used in various clinical conditions, although molecular biological evidence is insufficient due to delay in basic research. Here, we have summarized the history of NPWT, its mechanism of action, what is currently known about it, and what is expected to be known in the future. Particularly, attention has shifted from the four main mechanisms of NPWT to the accompanying secondary effects, such as effects on various cells, bacteria, and surgical wounds. This chapter will help the reader to understand the current status and shortcomings of NPWT-related research, which could aid in the development of basic research and, eventually, clinical use with stronger scientific evidence.

The role of the cord blood platelet gel in the management of a diabetic foot with tendon exposure

Diabetic foot infection is frequent in diabetic patients and is due to neuropathy, trauma or peripheral arterial disease. The presence of an abscess requires urgent drainage and specific antibiotic therapy. Patients with critical limb ischemia need revascularization and, subsequently the intervention of a plastic surgeon is often required in cases of exposure of tendons and ligaments. During the COVID-19 pandemic, a patient was refered to our department with an abscess on the dorsum of the left foot. After urgent drainage with tendon exposure, he started specific antibiotic therapy and underwent tibial vessels angioplasty. After infection healing cord blood platelet gel was applied, accelerating the healing process, with injection of its liquid part into the exposed tendons, thus retaining the vital functions of the tendons.

Fatty acid potassium improves human dermal fibroblast viability and cytotoxicity, accelerating human epidermal keratinocyte wound healing in vitro and in human chronic wounds

Effective cleaning of a wound promotes wound healing and favours wound care as it can prevent and control biofilms. The presence of biofilm is associated with prolonged wound healing, increased wound propensity to infection, and delayed wound closure. Anionic potassium salts of fatty acids are tested with commonly used anionic surfactants, such as sodium laureth sulphate (SLES) and sodium lauryl sulphate/sodium dodecyl sulphate (SLS/SDS). The normal human dermal cells demonstrated significantly greater viability in fatty acid potassium, including caprylic acid (C8), capric acid (C10), lauric acid (C12), oleic acid (C18:1), and linoleic acid (C18:2), than in SLES or SLS after a 24-hour incubation. Cytotoxicity by LDH assay in a 5-minute culture in fatty acid potassium was significantly lower than in SLES or SLS. in vitro wound healing of human epidermal keratinocytes during the scratch assay in 24-hour culture was more significantly improved by fatty acid treatment than by SLES or SLS/SDS. In a live/dead assay of human epidermal keratinocytes, C8K and C18:1K demonstrated only green fluorescence, indicating live cells, whereas synthetic surfactants, SLES and SLS, demonstrated red fluorescence on staining with propidium iodide, indicating dead cells after SLES and SLS/SDS treatment. Potassium salts of fatty acids are useful wound cleaning detergents that do not interfere with wound healing, as observed in the scratch assay using human epidermal keratinocytes. As potassium salts of fatty acids are major components of natural soap, which are produced by natural oil and caustic potash using a saponification method, this may be clinically important in wound and peri-wound skin cleaning. In human chronic wounds, natural soap containing fatty acid potassium increased tissue blood flow based on laser speckle flowgraphs after 2 weeks (P < .05), in addition to removing the eschars and debris. Wound cleansing by natural soap of fatty acid potassium is beneficial for wound healing.

Use of cord blood platelet gel to enhance healing of deep surgical site dehiscences after peripheral bypass

Surgical site dehiscence after lower limb revascularization through bypass represents a serious postoperative complication, especially in diabetic and obese patients, with subsequent risk of early graft failure, infection, sepsis, hemorrhage, major amputation and sometimes death. To prevent bypass exposure and subsequent complications, physicians recur to reoperation, antibiotic therapy, advanced dressing and vacuum-assisted closure therapy. To improve the process of wound healing, cord blood platelet gel can be used to fill deep and large wounds. Growth factors released from platelets in the cord blood platelet gel stimulate the process of healing and allow patients to be followed up in Outpatient Surgery, thus reducing hospital stay and costs, while providing excellent results.

A multistage combined approach to promote diabetic wound healing in COVID-19 era

When diabetes mellitus is not properly controlled with drugs and a healthy lifestyle, it exposes patients with advanced peripheral arterial disease or critical limb ischaemia (CLI) to the most serious complications, in particular lower limb ulcers. Surgical or endovascular treatments represent the first line of intervention; in addition, the adequate management of ulcers can guarantee not only a faster wound healing but also the improvement of the patient's prognosis. To speed up this process, negative pressure wound therapy (NPWT), platelet-rich plasma (PRP), and other advanced moist wound dressing have been proposed. During Coronavirus disease 2019 (COVID-19) pandemic, many patients with CLI and diabetes mellitus had difficult access to advanced treatments with a significant reduction in life expectancy. We report the cases of patients with non-healing ulcers and CLI treated with an empiric multistage approach after successful endovascular revascularisation; the postoperative course was eventful in all patients, and foot ulcers are currently in an advanced state of healing. The association between adequate revascularisation, systemic anti-inflammatory, and antibiotic therapy with the multistage advanced medications ensures healing of ulcers, limb salvage, and improvement of patient prognosis.

Local release of metalloproteinases and their inhibitors after a successful revascularisation procedure

An altered balance between metalloproteinases (MMPs) and their inhibitor tissue inhibitor of metalloproteinases (TIMPs) may influence the healing process of a minor amputation following a successful vein graft. To speed up this process, negative pressure wound therapy (NPWT) and advanced moist wound dressing have been proposed. We determined the systemic and local release of MMP-1, -2, -3, -9, TIMP-1, and TIMP-2 by enzyme linked immunosorbent assay (ELISA) technique and their influences in the healing process in 26 patients who underwent minor amputation after a successful revascularisation procedure. Twelve patients (group 1) were medicated with NPWT and 14 (group 2) with advanced moist wound dressing. Plasma samples were collected on the morning of surgery and thereafter at 1, 3, and 5 months; exudates were collected 3 days after surgery when amputation was performed and thereafter at 1, 3, and 5 months. Fifteen age-matched healthy male volunteers served as controls. All wounds healed in 5 ± 0.5 months. Follow-up plasma and local release of MMP-1, -2, -3, and -9 were overall significantly lower when compared with the preoperative levels, while those of TIMP-1 and -2 were significantly higher with no differences among the groups. Despite no differences in the healing process being observed among the two types of medications, at 1 month the local release of MMP-2 and -9 was significantly lower (P = .013 and .047, respectively) and that of TIMP-1 was significantly higher (P = .042) in group 1 as compared to group 2. A correct and aggressive local approach to the wound is able to promote the healing of the lesion stimulating the extracellular matrix turnover with local MMP/TIMP adequate balance and favouring the creation of granulation tissue. However, a successful restoration of an adequate blood flow remains the key point of a durable and rapid wound healing.

Different inflammatory cytokines release after open and endovascular reconstructions influences wound healing

Prodromal signs of a non-healing wound after revascularisation, which might be strictly linked with impending failure of vascular reconstructions, are associated with an inflammatory response mediated by several circulating adhesion molecules, extracellular endopeptidases, and cytokines. The aim of our study was to investigate the role of selected plasma biomarkers in the prediction of both wound healing and failure of infrapopliteal vein graft or percutaneous trans-luminal angioplasty (PTA) with selective stent positioning of the superficial femoral artery (SFA) in a population affected with critical limb ischaemia. A total of 68 patients who underwent either surgical or endovascular revascularisation of the inferior limb with autologous saphenous vein infrapopliteal bypass or PTA and selective stenting of the SFA were enrolled in our study. Patients were divided into two groups according to treatment: 41 patients were included in Group 1 (open surgery) and 27 in Group 2 (endovascular procedure). Plasma and blood samples were collected on the morning of surgery and every 6 months thereafter for up to 2 years of follow-up or until an occlusion occurred of either the vein bypass graft or the vessel treated endovascularly. Fifteen age-matched healthy male volunteers were considered a reference for biological parameters. Vascular cell adhesion molecule 1 [VCAM-1]/CD106, inter-cellular adhesion molecule-1 [ICAM-1]/CD54), interleukin-1 (IL-1), interleukin-6 (IL-6), tumour necrosis factor alpha (TNF-α), and metalloproteinases (MMP)-2 and -9 plasma levels were measured with enzyme-linked immunosorbent assay (ELISA) kits. The mean observed time to heal of 54 wounds was 13 ± 4 months, with no statistically significant differences among the groups. The healing failure of the remaining wounds was strictly related to an unsuccessful open (n = 12) or endovascular (n = 8) treatment. The 2-year primary patency rate was 65% (SE = .09) in Group 1 and 52% (SE = .1) in Group 2. When compared with mean concentration values of Group 1, VCAM-1 and ICAM-1 were always significantly higher during follow-up in patients of Group 2 (P < .05). Furthermore, in the same group, IL-6 and tumour necrosis factor alpha (TNF-α) were found to be significantly higher at 6- and 12-month (P < .05) when compared with surgically treated patients. Cox regression analysis showed that elevated plasma levels of VCAM-1, ICAM-1, IL-6, and TNF-α during follow up were strongly related to impaired wound healing and/or revascularisation failure (P < .05). Elevated plasma levels of inflammatory markers VCAM-1, ICAM-1, IL-6, and TNF-α may be related to the failure of wound healing and revascularisation procedures. Interestingly, we have observed that endovascular treatments cause a higher level of these inflammation biomarkers when compared with a vein graft, although wound-healing and patency and limb salvage rates are not influenced.

External Iliac Artery to Tibial Arteries Vein Graft for Inaccessible Femoral Artery

BACKGROUND

An endovascular-first approach to limb salvage and relief from lifestyle-limiting claudication is widely accepted. Stenosis or short occlusion of common, superficial femoral, and popliteal arteries can be corrected with percutaneous transluminal angioplasty (PTA) with stent positioning. Patency rates of these procedures are limited. We report our experience with external iliac artery to the infrapopliteal vessels vein grafts when the endovascular treatment fails.

METHODS

Between January 2013 and January 2019, 16 patients (16 limbs) were operated on for limb-threatening ischemia after the occlusion of PTA with stent positioning of the common, superficial femoral, and popliteal arteries. Three patients were treated at our hospital by interventional radiologists; the remaining were operated on elsewhere. An external iliac artery to the infrapopliteal vessels vein bypass graft was anatomically interposed to restore blood flow. End points of the study were death-related events, vein graft failure, and major (above- or below-knee amputation) or minor (foot or toe amputation) limb loss.

RESULTS

There were 12 men and 4 women. Mean age of patients was 68 years. Indication for the initial PTA with stent positioning of the common and superficial femoral artery was according to the Rutherford classification Grade I: Category 1, 11 patients (69%) and Category 2, 5 (31%) patients (Stage IIa and IIb according to Fontaine classification, respectively). Great saphenous vein was used in 14 (87%) cases and in 2 (13%) cases a composite graft with a segment of cephalic vein was required. The distal anastomoses were performed on the posterior tibial artery in 6 (37%) cases, anterior tibial artery in 4 (26%), and peroneal artery in 6 (37%). Four-year survival and primary patency rates were 71% (standard error [SE] = 0.15) and 73% (SE = 0.14), respectively. One graft occlusion required an above-knee amputation. Four-year limb salvage rate was 86% (SE = 0.13).

DISCUSSION

We recommend the external iliac artery as source of inflow in patients in whom the vein bypass cannot originate from the common femoral or from a more distal inflow source because of previous PTA with stent positioning or it is deemed hazardous.

Inflammatory biomarkers, vascular procedures of lower limbs, and wound healing

Abnormal, persistent inflammation after bypass surgery could prevent healing of an ischaemic foot lesion. In 37 patients with peripheral arterial disease (PAD) (Rutherford Grade III Category 5) who underwent infrapopliteal vein graft and midfoot amputation, plasma levels of fibrinogen, C-reactive protein (CRP), interleukin-1 (IL-1), interleukin-6 (IL-6), tumour necrosis factor-α (TNF-α), and matrix metalloproteinase-2 and -9 (MMP-2 and MMP-9) were determined preoperatively and during the follow up. Nine patients without clinical and Doppler evidence of arterial disease, who underwent post-traumatic midfoot primary amputation, were included in the experiment group, and 15 age-matched healthy volunteers served as control. In patients who had midfoot amputation for trauma, all wounds healed. Seven (19%) wounds in patients with an occluded graft healed, and five (13%) required major amputation because of a non-healing wound. Time required for complete healing of the lesion was similar between trauma and PAD patients (8 ± 2 months vs 11 ± 6, respectively, P = NS). Univariate analysis demonstrated that, in PAD patients, the postoperative high levels of TNF-α, IL-6, and MMP-2 and -9 were predictive for wound healing failure at 3, 6, and 9 months (P < 0.05), respectively. Furthermore, the subgroup of patients who experienced occlusion of the vein graft during follow up had a significant increase of MMP-2, -9, IL-6, and TNF-α at 3, 6, and 9 months (P < 0.05), respectively. Monitoring inflammatory markers allows the determination of patients at risk of healing failure of midfoot amputation after distal revascularisation and might predict the fate of the vein graft.

Efficacy of cord blood platelet gel application for enhancing diabetic foot ulcer healing after lower limb revascularization

The efficacy of umbilical cord blood platelet gel (CBPG) application on healing foot ulcers was analyzed in 10 diabetic patients treated for critical lower limb ischemia by surgical or endovascular arterial revascularization. During a 9-month period, 20 diabetic patients affected by critical lower limb ischemia with tissue loss were enrolled in this nonblinded, consecutive series, randomized clinical trial. After clinical evaluation, patients underwent endovascular or surgical revascularization of the affected limb, followed by minor amputations or surgical debridement of ischemic lesions. Patients were then randomly divided into two groups: 10 patients in Group A treated with standard wound care and 10 patients in Group B treated with topic application of CBPG. The CBPG protocol consisted of platelet gel application twice a week for 4 weeks and then once a week for an additional 4 weeks. Healing was assessed by direct ulcer dimension tracing onto clear plastic sheet and subsequent computerized planimetry. The mean pretreatment and post-treatment ulcer areas at 30 days for Group A were 15.1 cm² and 8.1 cm², respectively, and for Group B were 15.7 cm² and 3.25 cm², respectively; resulting in a mean ulcer area reduction of 46% for Group A and 79% for Group B patients (P < .01). These observations suggest CBPG application can promote more rapid wound healing than standard care, and indicate the need for a randomized, multicenter trial to confirm clinical efficacy.

Is the Endovascular Treatment of Mild Iliac Stenoses Worthwhile to Improve Wound Healing in Patients Undergoing Femorotibial Bypass?

BACKGROUND

After an infrapopliteal reconstruction, minor amputations are frequently required, but even in the case of successful revascularization, wound healing is a major concern. We studied the role of iliac artery inflow correction in patients undergoing infrapopliteal vein grafts to improve the heal of midfoot amputation.

METHODS

Thirty-eight patients affected with Rutherford grade III category 5 peripheral arterial disease, who underwent successful simultaneous iliac endovascular procedure, infrapopliteal reversed vein bypass graft, and minor amputation, were enrolled in this retrospective study. The population was divided in group 1 (20 patients) with inflow vessels Trans-Atlantic Inter-Society Consensus Document on Management of Peripheral Arterial Disease (TASC) II type B atherosclerotic lesions and group 2 (18 patients) with TASC II type A atherosclerotic lesions determining an invasive pressure drop greater than 15 mm Hg. Fifteen patients (group 3) undergoing infrapopliteal reversed vein bypass graft without associated inflow procedures (TASC II type A and invasive pressure drop greater than 15 mm Hg) were matched with group 2 based on propensity score. Healing was calculated by subtracting the final ulcer area from the initial ulcer area and dividing by the number of follow-up months to obtain the total area healed per month (cm²/month). Stepwise logistic regression analysis adjusted for demographics and medical comorbid conditions was used to test the association between wound healing and treatment modalities.

RESULTS

Forty-three patients were available for further analysis. Ten patients were excluded because of graft occlusion with consequent impairment of wound healing. After midfoot amputations, mean wound diameter was 20 ± 8 cm², and mean healing time was 10 ± 4 months (range 3-20 months; median 9 months). Wounds of groups 1 and 2 healed faster than those of group 3 at 4 and 8 months (P < 0.02 and P < 0.001, respectively; P < 0.04 and P < 0.001, respectively). Multivariate analysis demonstrated the association between wound healing and inflow correction (P < 0.001).

CONCLUSIONS

An aggressive treatment is necessary to obtain the heal of the ischemic wounds. The most important predictive factor for nonhealing wounds is the absence of inflow correction. We demonstrated that the inflow should be also corrected in the presence of subclinical lesions.

Matrix metalloproteinases and risk stratification in patients undergoing surgical revascularisation for critical limb ischaemia

Critical limb ischaemia (CLI) is the most advanced form of peripheral artery disease (PAD) and it is often associated with foot gangrene, which may lead to major amputation of lower limbs, and also with a higher risk of death due to fatal cardiovascular events. Matrix metalloproteinases (MMPs) seem to be involved in atherosclerosis, PAD and CLI. Aim of this study was to evaluate variations in MMP serum levels in patients affected by CLI, before and after lower limb surgical revascularisation through prosthetic or venous bypass. A total of 29 patients (7 females and 22 males, mean age 73·4 years, range 65-83 years) suffering from CLI and submitted to lower extremity bypass (LEB) in our Institution were recruited. Seven patients (group I) underwent LEB using synthetic polytetrafluoroethylene (PTFE) graft material and 22 patients (group II) underwent LEB using autogenous veins. Moreover, 30 healthy age-sex-matched subjects were also enrolled as controls (group III). We documented significantly higher serum MMPs levels (P < 0·01) in patients with CLI (groups I and II) with respect to control group (group III). Finally, five patients with CLI (17·2%) showed poor outcomes (major amputations or death), and enzyme-linked immunosorbent assay (ELISA) test showed very high levels of MMP-1 and MMP-8. MMP serum levels seem to be able to predict the clinical outcomes of patients with CLI.

The Effects of Negative Pressure by External Tissue Expansion Device on Epithelial Cell Proliferation, Neo-Vascularization and Hair Growth in a Porcine Model

While pre-treating a fat transplant recipient site with negative pressure has shown promise for increasing the fat survival rate, the underlying mechanisms have not been investigated, partly due to challenges related to immobilization of vacuum domes on large animal subjects. The aim of this study was to examine the effect of negative pressure treatment by External Tissue Expansion Device (ETED) on fat grating recipient sites in a porcine model. The ETED was designed to provide negative pressure on the dorsum of swine. Pressure treatment (-70 mmHg) was applied for 1 or 3 hours every other day for 10 and 20 treatments. The treated areas (3.5 cm in diameter) were harvested and examined for histological changes, vessel density, cell proliferation (Ki67) and growth factor expression (FGF-1, VEGF and PDGB-bb). The application of the ETED increased epidermis thickness even after 1-hour treatments repeated 10 times. The results of Ki67 analysis suggested that the increasing thickness was due to cell proliferation in the epidermis. There was a more than two-fold increase in the vessel density, indicating that the ETED promotes vascularization. Unexpectedly, the treatment also increased the number of hair follicles. Negative pressure provided by the ETED increases the thickness of epidermis section of tissue, cell proliferation and vessel density. The porcine model provides a better representation of the effect of the ETED on skin tissue compared to small animal models and provides an environment for studying the mechanisms underlying the clinical benefits of negative pressure treatment.

Application of autologous platelet-rich plasma to enhance wound healing after lower limb revascularization: A case series and literature review

Dermal tissue loss in patients affected by critical limb ischemia represents a serious wound-healing problem, with high morbidity, prolonged hospital stay, and high patient care costs. Treatment of ischemic foot lesions requires limb revascularization by endovascular or open surgical intervention and individualized patient-specific wound care, including antibiotic therapy; devitalized/infected wound debridement; and advanced wound dressing. In selected patients, spinal cord stimulation, vacuum-assisted closure therapy, and bioengineered tissue or skin substitutes and growth factors have been shown to improve wound healing. In this study, we present our preliminary results on topical application of autologous platelet-rich plasma to enhance the process of wound healing after revascularization of lower limbs in patients affected by critical limb ischemia.

Poor Prognosis in Critical Limb Ischemia Without Pre-Onset Intermittent Claudication

BACKGROUND

Some patients with critical limb ischemia (CLI) lack symptoms of intermittent claudication (IC) before the onset of CLI. We studied the outcome of such patients, because this is currently unknown. METHODS AND RESULTS: For retrospective exploratory analysis, we divided 225 patients (265 limbs) with CLI into 2 groups: 142 patients (172 limbs) without a history of IC (non-IC group) and 83 patients (93 limbs) with IC (IC group). We examined comorbid factors and found that a higher proportion of patients in the non-IC group failed to undergo arterial revascularization (49% vs. 20%, P<0.0001) due to progressed limb ischemia and infection. We then analyzed 140 patients (161 limbs) with revascularization. Patients in the non-IC group were more likely to have diabetes mellitus (P=0.03), hypoalbuminemia (P=0.02), advanced Rutherford's classification (P=0.0007), worse ambulatory function (P=0.009), and longer postoperative stay (P=0.04). Amputation-free survival was lower in the non-IC group (P=0.005). On Cox regression analysis, hemodialysis (P=0.002), coronary artery disease (P=0.04), cerebrovascular disease (P=0.02), non-ambulatory status (P=0.02), and non-IC (P=0.01) were independent risk factors for lower amputation-free survival.

CONCLUSIONS

Patients without IC before CLI onset have several unique features, and non-IC is an independent risk factor for poor outcome.

VAC therapy for the treatment of complex wounds after cardio-thoracic surgery

The aim of this study is to report our experience about the treatment of complex sternal and thoracic wounds following cardiothoracic surgery, using vacuum-assisted closure (VAC therapy. Twelve patients presenting with sternal (five cases) and thoracic (seven cases) wounds that were difficult to heal were treated through VAC therapy after the first surgical debridement. The duration of VAC application ranged from 12 to 36 days with an average hospital stay of 24·6 ± 11·4 days. During a mean follow-up of 12 months, we observed complete wound healing in seven cases (58·3%), in an average period of 25·5 ± 14·3 days; one patient died during follow-up, two patients were lost to follow-up and two patients required definitive surgical closure of the wound cavity. In conclusion, VAC therapy promotes faster wound healing, with shorter hospital stay and subsequent lesser in-hospital cost, reducing the mortality rate in the long run. It also promotes early rehabilitation and alleviates the need for a second procedure, thus improving patient satisfaction, with minimal discomfort or inconvenience.