New EACTS/STS guidelines on the diagnosis and treatment of aortic ‘organ’ diseases: are you ready for prime time?

Ten years after the previous aortic guidelines release in 2014 [1], the European Association for Cardiothoracic Surgery (EACTS) together for the first time with the American Society of Thoracic Surgeons (STS) provides new recommendations for the diagnosis and treatment of aortic diseases. The 2024 update arrives in a year of a remarkable innovation in this field. Indeed, marking the 30th anniversary of the first thoracic endovascular aortic repair (TEVAR) performed at Stanford and then published in 1994 by Dake et al. [2] for the treatment of a descending thoracic aortic aneurysm.

The new guidelines are a clinical practice ‘opera magna’ reported in 195 pages and 19 chapters that tackle all relevant aspects of aortic diseases and are summarized in 36 tables of recommendations [3].

The directions (NEWS) provided in this manual of ‘the good aortic doctor’ can be summarized in 4 cardinal points:

1. (N)omenclature. The shift in perception that now recognizes the aorta as an organ in its own right. If you pay attention to the 2 words ‘aorta’ and ‘organ’ you will suddenly find similarities. They both come from Ancient Greek. Aorta derives from ‘ἀείρω’ (aíro) something that lift or raises [4]. Organ is ὄργανον (órganon) composed of ‘ergo’ which means power, work and energy and becomes ‘ergon’: that is something that serves as a tool for power, work, and energy [4]. In medicine, it defines a part of the body that structurally forms a functional unit specialized to perform a specific function. Never has it been more appropriate to call the ‘new’ aortic organ a ‘raised organ’.

2. (E)ndovascular treatment. TEVAR serves as first-line intervention for nearly every pathology involving the distal arch or descending thoracic aorta. It is strongly recommended for the treatment of complicated acute type B aortic dissection and for those with ‘high-risk features’, ulcers and traumatic ruptures. Likewise, a class IIa recommendation is now supporting membrane stabilization (PETTICOAT) in acute dissections in cases where adequate lumen decompression (with distal malperfusion) cannot be established by TEVAR alone [3]. Branched or fenestrated endovascular aneurysm repair is also not inferior to open surgery for the treatment of thoraco-abdominal pathologies (class IIa).

   When referring to open surgical treatment, the adjunct of an antegrade stent graft implant with the frozen elephant trunk (FET) becomes the treatment of choice for most arch diseases. A class of recommendation IIa is provided for acute type A or non-A non-B aortic dissections (Table 6), complicated type B aortic dissections unsuitable for TEVAR (Table 7) and chronic aortic diseases (Tables 14 and 15). It also has the advantage of creating a durable proximal sealing zone for further endovascular or open interventions in the thoraco-abdominal aorta [5]. Additional development of stent grafts and deployment systems could help seal off more proximal aortic segments in the future.

3. (W)ide consensus. A task force including professionals from the European (EACTS) and American (STS) societies was created. A comprehensive review was then put forth by an external panel of worldwide experts in the field. This approval made it possible for the guidelines to be published simultaneously in the European Journal of Cardio-Thoracic Surgery and the Annals of Thoracic Surgery [3]. A unique general agreement was never pursued before.

4. (S)urgical indications. A lower threshold is applied for elective surgery on the ascending aorta (not root) when the aortic diameter is 52 mm or more, replacing the old 55 mm cut-off. The authors support this recommendation with the papers of Kalogerakos et al. [6] and Wojnarski et al. [7] (cumulatively, that is evidence from >2300 pts) reporting a ‘hinge-point’ of 52.5 and 53 mm, respectively. The writing committee has also stressed the need to tailor indications to the patient's individual features, including phenotype of the dilatation (hence the different recommendations for the root at 50 mm), operative and natural history risk factors.

Notably, the level of evidence (which reflects the quality of data from clinical trials and other research studies) supporting most of the class of recommendations (denotes a general agreement that a specific intervention is beneficial, useful and effective) in this new guidelines is largely categorized as ‘level C’. Indeed, despite the large number of publications reported in the text (n = 983 references), the studies heavily rely on small cohorts of patients, retrospective analyses, and expert consensus. As a result, multiple reviewers commented negatively on some recommendations proposed by the committee because they were not supported by strong data. Areas of controversy have been prophylactic surgery at 45 mm or more for patients with Marfan syndrome even without high-risk features, measuring aortas outer-to-outer edge rather than inner-to-inner and recommendations regarding the use of high to moderate lower body hypothermic circulatory arrest and selective antegrade cerebral perfusion for complex arch procedures.

On the other hand, a strong agreement was obtained regarding the importance of the aortic teams and its healthcare implications. The economic burden of aortic disease is high. The median hospital cost for patients treated for thoracic aortic dissections ($6102 medical, $26 896 endograft, and $30 372 surgery) is 50% higher in comparison to matched controls [8]. For this reason, transfer to ‘centres of excellence’ providing variety of expert specialists available on a 24/7 basis should be considered for every patient with multisegmental aortic disease. The low level of evidence supporting almost all recommendations should be a stimulus for the entire aortic community to strive to generate more data through prospective randomized controlled trials. Several areas of interest necessitate more attention to research, such as identifying diagnostic biomarkers for confirming aortic dissection, standardizing measurements of aortic dimensions, determining the type of cannulation and extent of repair required in type A aortic dissection, evaluating the introduction of new endovascular devices for the treatment of complex aneurysms (mind the arch) and so on.

To continue the legacy of innovation, in the year of TEVAR’s 30th anniversary, we should lead trials evaluating new devices and techniques. The new guidelines established the structural foundation necessary to meet the needs of treating the aortic diseases and offered the opportunity to stay connected as a team.

Make sure you are up to date on this document and take part to the new season of ‘the good aortic doctor’ just delivered to your screen!

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