4 Committee discussion
4.1 The committee noted that the evidence for VAC Veraflo Therapy system compared with negative pressure wound therapy was mainly from retrospective observational studies of low methodological quality. It agreed that, given the substantial heterogeneity in different patients (including age and comorbidities), wound types and wound characteristics, such studies are not an appropriate basis for estimating relative clinical effectiveness. It also noted that the most robust evidence (the randomised controlled trial by Kim et al. 2020) showed no statistically significant clinical benefit for VAC Veraflo Therapy system compared with negative pressure wound therapy. The clinical experts explained that, in their experience, VAC Veraflo Therapy system has shown benefits over standard negative pressure wound therapy for appropriately selected people with difficult to heal wounds. The clinical experts said they had seen a reduction in dressing changes, faster tissue granulation, shorter wound healing time, and a shorter time to surgery. The committee felt that the technology showed promise and plausibility based on clinical expert advice, but that this was not supported by the available evidence. The committee concluded that there was not enough good-quality evidence to make a definitive judgement about the benefits of this technology compared with negative pressure wound therapy or advanced wound care in the NHS.
Negative pressure wound therapy (without instillation) is the relevant comparator for VAC Veraflo Therapy system
4.2 The committee heard from clinical experts that VAC Veraflo Therapy system would normally be used in place of, or as a temporary alternative to, negative pressure wound therapy. The clinical experts explained that advanced wound care was of limited relevance as a comparator because it would be used earlier in the care pathway, and sometimes also after treatment with VAC Veraflo Therapy system or negative pressure wound therapy. The committee considered negative pressure wound therapy to be the most appropriate comparator.
4.3 The committee noted that the patient populations in the evidence are heterogeneous, involving a mixture of people with different wound types and comorbidities. The clinical experts agreed that the patient population eligible for VAC Veraflo Therapy system is complex and broad. They also highlighted that the clinical pathway for people with non-healing wounds is not clearly defined and that clinical practice varies. The clinical experts said that the decision to offer VAC Veraflo Therapy system requires specialist knowledge and experience. They added that it is used slightly differently in each of their clinics because of the different types of wounds they treat and the different aims of therapy. One expert said that in their clinic VAC Veraflo Therapy system is used after debridement, especially for people who have an infection to help with healing. They also said that VAC Veraflo Therapy system is most commonly used in people with diabetic foot problems before limb salvage. The committee was aware that outcome reporting is particularly problematic in this field because of the heterogenous population and setting, as well as the use of non-standardised definitions and measurements. The committee concluded that the complexity of the population, together with the heterogeneity of the available evidence, makes generalisation of study results difficult.
4.4 None of the available published studies were done in the UK. The most robust evidence for VAC Veraflo Therapy system came from a multicentre randomised controlled trial done in the US (Kim et al. 2020). One of the clinical experts explained that wound management in the US is likely to be very different from the NHS. The trial (Kim et al. 2020) involved specialist tertiary centres where the aim of treatment is to surgically debride wounds to acute status. Microbiology is then reviewed every 48 hours until definitive or reconstructive surgery can be done to close the wound. In these centres debridement may be done several times until microbiology results are sterile. The clinical experts said that this does not happen in the NHS. They also noted that in most of the included studies chronic wounds were debrided back to an acute wound status before VAC Veraflo Therapy system treatment was applied. Because of this, they said caution was needed when interpreting its clinical efficacy in chronic wounds based on these studies. The clinical experts also explained that in the NHS many people with wounds eligible for treatment with VAC Veraflo Therapy system are not treated by acute surgeons but by tissue viability nurses and vascular clinicians. Other clinical experts also agreed that the care pathway evaluated in Kim et al. (2020) did not fully reflect their experience of using VAC Veraflo Therapy system in the NHS. The committee concluded that the evidence does not fully reflect NHS practice and that data from non-UK studies are likely to have limited generalisability to the NHS.
4.5 The clinical experts said that, given how the technology is used in the NHS, length of hospital stay is likely to be a poor choice of outcome and does not take into account other important clinical outcomes including quicker time to surgery (plastic surgery), better overall wound healing, and reduced negative pressure wound therapy time. One expert said that the technology could increase the patient's length of stay but reduce the overall impact on other services because of faster healing. It was also noted that length of hospital stay may be confounded by other factors, such as hospital discharge procedures and the availability of community care. The clinical experts agreed that, to fully understand the clinical benefits of the technology in the NHS, the entire wound healing journey should be considered. They also agreed that wound closure is the most important outcome. The committee concluded that the outcome of length of hospital stay may not be an appropriate primary clinical outcome.
4.6 Some important clinical outcomes from the scope had not been reported in the evidence. In particular, none of the published evidence reported health-related quality of life and patient-related outcome measures (such as pain). The committee agreed that this was a substantial omission, and that how VAC Veraflo Therapy system affects patient experience is poorly understood. One clinical expert also explained that improving the quality of granulation tissue in the early healing stages was an important benefit of the technology that was not captured in the evidence. The committee concluded that further research would be helpful on the technology's effect on these outcomes.
VAC Veraflo Therapy system has plausible benefits for people over standard negative pressure wound therapy
4.7 The clinical experts said that people who are offered treatment with VAC Veraflo Therapy system have usually had a non-healing wound for months and that this is likely to have made their quality of life poorer. They explained that when people see the rapidly improved appearance of their wound, which can happen after treatment with VAC Veraflo Therapy system, it can give them much-needed hope. The experts said that in their experience people tend to accept and respond well to therapy. They said other potential benefits were fewer dressing changes, and less wound exudate, odour and spoiling of clothing and bed linen.
4.8 The committee heard that people who are older or physically disabled are more likely to have chronic and complex wounds. People with certain family origins (South Asian, Chinese, black African and African-Caribbean family origins) are more prone to poor wound healing because of their increased risk of diabetes. Age, disability, and race are protected characteristics. The committee also heard, however, that people with serious mental health or cognitive impairment may have difficulty keeping the system in place. The committee concluded that people with disabilities, including those with serious mental health or cognitive impairment, would not be disadvantaged by the recommendations. This is providing that clinicians act in the interest of their patients, in line with their usual responsibilities.
4.9 The clinical experts explained that in the NHS VAC Veraflo Therapy system is used as a temporary treatment at a specific point in wound healing to speed up wound healing. They explained that it's usually used for about 2 weeks and that when the wound bed improves, treatment is changed to standard negative pressure wound therapy or standard wound care with dressings. One expert explained that once a wound has a good level of granulation tissue it can be treated with conventional dressings. They said that people are routinely discharged with open wounds that are then managed in community care. The other experts noted that in their experience VAC Veraflo Therapy system is used as a bridging therapy and helps reduce the time between surgical treatments by preparing the wound bed for reconstruction.
VAC Veraflo Therapy system should be used in hospital by specialist healthcare professionals trained in using it
4.10 The clinical experts said that, because of the complexity of the wounds, a multidisciplinary team, including a trust specialist trained in using VAC Veraflo Therapy system, should decide when to offer treatment with VAC Veraflo Therapy system and when to stop it. The clinical experts thought that this level of specialism was not widely available in community care. Also, using the system in community care is difficult because of the frequency of dressing and other consumable changes. The clinical experts said that it is only offered in secondary or tertiary care. One clinical expert added that offering VAC Veraflo Therapy system in a community setting should not be ruled out if appropriate support mechanisms are in place.
A standard dwell time of 10 minutes and cycle length of 3.5 hours should be considered for VAC Veraflo Therapy system
4.11 There was no evidence on the best dwell time and cycle length for VAC Veraflo Therapy system. The clinical experts explained that the instillation fluid needs enough dwell time to infiltrate the wound and for the exudate to mix with the solution for it to be effectively removed. They said that the VAC Ulta device comes with standard manufacturer recommended settings, but that it also enables healthcare professionals to modify settings based on clinical judgement. The clinical experts noted that in their experience the standard setting of 10 minutes dwell time and a 3.5 hour cycle length recommended by the manufacturer is normally appropriate for most wounds. One said that in some situations they increase the number of cycles to every 1 hour to 2 hours at the beginning of therapy to speed up wound healing. The committee concluded the standard settings recommended by the manufacturer were appropriate.
4.12 The key clinical parameters that drive cost savings estimates in the economic modelling, such as surgical debridement and length of stay, were very uncertain. This is because the evidence was mainly made up of retrospective observational studies from outside the UK, and because of uncertainties in the relationship between length of stay and length of therapy. The committee noted that there were no well-designed studies in the NHS. It concluded that more research was needed to establish the clinical and cost benefits of VAC Veraflo Therapy system in the NHS and that in the meantime any cost modelling was likely to be flawed.
The committee concluded that further research is needed to address uncertainties about the clinical effectiveness of VAC Veraflo Therapy system compared with negative pressure wound therapy alone in the NHS. It advised that research should compare VAC Veraflo Therapy system with negative pressure wound therapy in randomised controlled trials in NHS hospitals. The clinical experts said that there are difficulties with running high-quality trials in wound care. These include nursing time, funding, and difficulty recruiting enough patients because of a possible lack of equipoise (that is, clinicians and trial participants may be unwilling to risk randomisation to a treatment that they believe to be inferior). Despite the challenges, clinical experts said that high-quality randomised controlled trials were still possible and necessary. The committee agreed that the most important outcome should be time to complete wound closure. Other outcomes should include health-related quality of life (including pain outcomes) and length of therapy with VAC Veraflo Therapy system and its impact on length of hospital stay.
The committee also encouraged data collection from registries. It agreed that large-scale real-world data collection in the form of registries may help future decision making around the adoption of VAC Veraflo Therapy system. For example, in providing confidence in assumptions made in the economic modelling.