The Society of Thoracic Surgeons (STS) and the American Association for Thoracic Surgery (AATS) have released a new clinical practice guideline that includes key recommendations for the management of patients with type B aortic dissection (TBAD). The guideline was published online today in The Annals of Thoracic Surgery and The Journal of Thoracic and Cardiovascular Surgery.
There has been an explosion of information in the form of research reports of varying quality regarding the treatment of type B dissection over the past decade. This guideline is unique in that it provides surgeons with a comprehensive and up-to-date summary of the state of the evidence, while also serving as “safeguards” that outline treatment options and best practices in certain scenarios. . This is a first for any document in the area of type B dissection management.”
G. Chad Hughes, MD, author, Duke University Medical Center, Durham, NC
The new clinical practice guideline offers evidence-based recommendations that include the use of a “stepped approach” to the evaluation and treatment of patients with uncomplicated (not immediately life-threatening) TBAD. danger), followed by close clinical monitoring.
Aortic dissection is a serious condition and can be fatal if not treated quickly. The aorta is the main and largest artery in the body, carrying oxygen-rich blood from the heart to all organs and other parts of the body. A dissection of the aorta occurs when a tear develops in its wall. The wall consists of three layers and this tearing allows blood to flow between the middle and outer layers causing them to separate (dissect). “Type B” describes the location of the tear. In a type B dissection, the tear originates in the lower (descending) part of the aorta in the chest and may extend into the abdomen.
According to the guideline (and historically), aggressive medical therapy is the first step and is considered the gold standard for the management of patients with uncomplicated TBAD, while open surgery should be reserved for complicated cases (leading the life-threatening). Over the past decade, however, TBAD treatment technology and techniques have evolved rapidly, particularly in terms of less invasive treatment options for the disease.
In fact, one of the most important elements of the guideline is the new role of prior endovascular treatment such as thoracic aortic endovascular repair (TEVAR) in patients with uncomplicated TBAD, explained author Dawn S. Hui, MD, of the University of Texas Health Science Center in San Antonio.
In the early phase of treatment, surgery was previously reserved for patients who had complicated TBAD; in later phases, for patients who have had disease progression, Dr. Hui said. Now, surgeons may be able to identify subsets of patients with uncomplicated TBAD who are at higher risk for progressive disease and treat them earlier with TEVAR; before progression develops. However, this recommendation remains secondary to medical management and patient selection still needs to be better defined in the future.
For complicated TBAD patients, TEVAR or open surgery, depending on the anatomy, should be the first-line treatment, according to the guideline. The collective data demonstrated better outcomes with TEVAR for these patients compared to open surgery or medical therapy alone.
The guideline also states that for some patients with TBAD (i.e. those with connective tissue disorders or chronic TBAD) whose disease has progressed despite medical therapy, a “more durable” open surgical repair may be recommended over TEVAR.
“We expect this guideline to improve the quality of care for patients with TBAD by providing surgeons with the most up-to-date summary of when and how to effectively use which therapies, whether open surgery, endovascular therapy or a combination of the two on the patient’s life,” Dr. Hui said.
STS believes that the practice of summarizing current scientific evidence in clinical practice guidelines and recommendations can help improve surgical outcomes, as well as the quality of patient care. In this case, to identify relevant evidence, a systematic review was described and an extensive literature search was conducted by a guideline steering committee. The group then drafted and developed recommendations based on a comprehensive and methodical assessment of 50 highly cited articles that were included in the final review.
“Unlike individual studies, clinical practice guidelines are unique because they are a high-quality summary and synthesis of what is already known about this topic,” Dr. Hui said. “Guidelines are written through a scientifically rigorous process. Thus, they can help resolve conflicting results from different studies or identify treatment options best suited to specific circumstances.”
Crucially, Dr Hughes said that with these new guidelines, the writing group was able to see the evidence summarized in a way that “reinforces what little we actually know about how best to treat these patients”. More high-quality studies, namely randomized controlled trials, are needed, he explained. These are studies where patients are randomly assigned to one treatment or another and then followed over time to determine which treatment is best for the patient in the long term.
“As a surgical community, we’ve been saying this for a decade, but now is the time to finally do it,” said Dr Hughes, who shared the plan is to update the TBAD guideline within the next 5 years to reflect the strengthening of scientific evidence.
Dr. Hui explained that although there are still gaps in knowledge and further studies are certainly needed, the role and timing of certain therapies are now better defined with this guideline.
The Society of Thoracic Surgeons
MacGillivray, TE, et al. (2022) Society of Thoracic Surgeons/American Association for Thoracic Surgery clinical practice guidelines on the management of type B aortic dissection. Annals of Thoracic Surgery. doi.org/10.1016/j.athoracsur.2021.11.002.