At the European Society for Vascular Surgery (ESVS) meeting (19–22 September, Lyon, France), Vascular News spoke to Florian Dick (University of Bern, Bern, Switzerland) about the new Global Vascular Guidelines for chronic limb-threatening ischaemia, which were presented to delegates as part of the scientific sessions. Dick told Vascular News about the main message behind the guidelines, and how they will form a framework around which the evidence base can grow. The guidelines are expected to be published online in the first quarter of 2018.
What is the main message of the new global vascular guidelines for chronic limb-threatening ischaemia?
FD: The central message is to approach the patient in a holistic way with a planned scheme; patient risk, limb threat assessment according to the so-called WIfI concept and anatomic assessment according to GLASS afterwards. Only then you can decide on how to treat the patients, as you have a basic matrix to predict risks and outcomes. Then you put in your differential treatments and you assess again. You have the chance to follow the patient in a very structured way, and make sure (i.e. measure) that what you are doing leads to improvement. If it does not, you change your treatment approach. It is very much an approach copied from the oncology world, where you have an objective TNM staging system and you restage and restage until you are sure your approach is effective.
How were these guidelines decided when there is a lack of level 1 evidence?
FD: It is true that these guidelines do not reflect existing evidence, but the aim is to provide a universal scheme or a matrix to use in validation trials or evaluation. This is a framework to put upcoming evidence into. It consists of several ‘boxes’ according to a three-dimensional matrix, where you enter the limb threat measured by WIfI—wound, ischaemia, foot infection—stages, the patient risk and the vascular anatomy. Ideally you would have clusters of patients and you would test your therapeutic approaches in each of these boxes to decide which patient would benefit most from what treatment. But we are not there yet, so we provide the framework for systematic assessment of the patient, the problem, and to follow through to outcomes.
How have the other specialties that work on revascularisation of the lower limb been brought together to incorporate the guidelines?
FD: This has been sponsored by the three leading vascular surgical societies—the European Society for Vascular Surgery (ESVS), the Society for Vascular Surgery (SVS), and the World Federation of Vascular Societies (WFVS). It has been written and conceived by an expert panel consisting of all the medical specialties that treat vascular patients, including vascular surgeons, interventional radiologists and cardiologists, vascular physicians and podiatrists. It was difficult to organise the collaboration between these large societies and it would not have been possible to include more official societies and all their needs. There was the follow-up consensus paper of TASC III which eventually did not work out between the several specialties. But many decided to follow this new initiative, which is less lesion based but uses a holistic patient approach.
How does this differ from the TASC approach?
FD: This is a different approach to TASC, which goes lesion by lesion and how each of them should be treated technically. The new view is to evaluate the whole limb, the whole patient first and see what the patient really needs. You want to integrate the whole patient risk regarding perioperative outcome and the problem of the limb (not only its perfusion) to be able to treat the patient’s situation, not only a lesion. What the patient wants is to keep the foot functioning, not hurting, and without wounds. The patient does not care about whether the lesion is treated or not. They want to have a functioning leg that does not hurt and does not have any lesions.
Who are the architects of the guidelines?
FD: The driving force came from the three co-editors, Michael Conte, Andrew Bradbury and Phillippe Kohl, each of whom represent one of the sponsoring societies. Joe Mills is one of the leading people behind the WIfI concept, which is a huge leap forwards because it moves away from a purely perfusion perspective, and integrates all the other factors associated with limb threats. It integrates not only ischaemia or perfusion (the “I”), but assesses also wound and foot infection. John White is one of the central coordinators, and Rob Fitridge and Kal Suresh both represent the World Federation to make sure the perspective stays global. Jean-Baptiste Ricco, the former editor-in-chief of the European Journal of Vascular and Endovascular Surgery (EJVES) and myself were elected to represent the European perspective on this truly global initiative.
Can you explain the GLASS classification and its use?
FD: The GLASS—global anatomic staging system—classification really relates to the arterial path down the limb. After the step back to see the holistic scheme which integrates the person and the problem (wound, perfusion and infection), you need to go into more detail for the anatomic scheme of the arterial path. With GLASS we have a matrix that assesses the two levels (fem-pop and tibial) regarding arterial vascularisation options with the aim of restoring one path to the foot. Essentially, GLASS looks at the distribution and the severity of the different lesions along the whole limb, and grades them against the chances of success with endovascular treatment.
How is the question of bypass versus endovascular being addressed in the guidelines?
FD: The guidelines are essentially based on the available information we have. Besides a few registry and observational analyses most information comes from the BASIL (Bypass versus angioplasty in severe ischaemia of the leg) trial conducted in the UK, where we saw that patients with a positive prognosis and a life expectancy of over two years will benefit from bypass surgery, because it is more durable with a more direct revascularisation. But again, the new guidelines only provide the scheme and a matrix where we have to yet fill in the knowledge; it is a framework that needs to be filled with evidence.
So the WIfI and GLASS approaches help give clarity on how to predict critical limb-threatening ischaemia trial outcomes?
FD: Exactly. This is a predictive arrangement and now we have to validate it with outcomes. It also proposes a set of standardised outcome measures that make sense clinically, but that can also be measured objectively and compared. This is all about creating a framework for comparisons, across different institutions, different techniques of revascularisation and different countries. The most important aspect we want to integrate is that the concept does not concentrate on North America or Western Europe; it integrates the views of the whole world, so these truly are global vascular guidelines. This also makes it difficult because the means and resources that are available for these patients are highly different in different regions of the world. Health systems are very different; we have to integrate those thoughts as well, not only to have a perspective for very high income countries where they can invest everything into these patients, but to integrate the views of the majority of patients globally. For example, India, China, and Asia more generally have a very important place in it because they have high prevalence of diabetes and they may not have the same means. It really provides a framework for comparisons and it will be a living document that will grow with evidence and get more specific. However, at the moment it does not give you an exact guideline on what to do technically in each instance but instead on how to approach a patient. I think this is the primary sense of these guidelines, but with time and re-evaluation, they will grow into practical clinical (and technical) guidelines.
Where will the guidelines be published?
FD: This document will be endorsed by the ESVS and SVS, as well as the WFVS. They will come out as a conjoint publication in the EJVES and the Journal of Vascular Surgery, so there is a lot of interest from both major societies to have a consensus document that will hopefully be generally accepted and live. It comes with a lot of tools, with apps where you can easily calculate your stages and your grades and this would then be used of course to follow your own patients to categorise them and add some outcome data. Only if we produce and generate more and valid evidence we will learn how to apply these schemes, and how to serve our patients best, eventually.