Study Suggests Anatomic Criteria to Determine Appropriateness of TEVAR in Uncomplicated Type B Aortic Dissection
January 8, 2018—The Society for Vascular Surgery (SVS) announced the publication of findings that suggest thoracic endovascular aortic repair (TEVAR) may be appropriate in uncomplicated type B aortic dissection (TBAD) based on several anatomic criteria determined by CT imaging. The study was published by Samuel I. Schwartz, MD, et al in Journal of Vascular Surgery (2018;67:78–84).
SVS noted that, historically, the standard of care for uncomplicated patients with TBAD has been medical management because of favorable 1-year survival rates compared with open repair of the descending thoracic aorta. However, medical management alone is associated with a 40% incidence of aneurysmal dilation of the outer wall of the false lumen in the first 5 years.
In addition, there have been few data on which patients benefit from early TEVAR. Recent data suggest that TEVAR coverage of the proximal entry tear in acute TBAD complicated by persistent pain, impending aortic rupture, and/or distal aortic branch malperfusion results in superior 30-day mortality over medical therapy. Further, it appears that aortic remodeling occurs along the stented segment of the aorta, preventing aneurysmal degeneration.
As summarized by SVS, investigators from Massachusetts General Hospital, led by Mark F. Conrad, MD, retrospectively reviewed their experience treating 254 patients presenting with uncomplicated TBAD from 2000 to 2013 and who were followed with serial CT imaging. The goal of the study was to identify clinical and anatomic factors associated with the need for late (defined as > 180 days from presentation) aortic intervention in patients presenting with uncomplicated TBAD.
At a mean follow-up of 6.8 years, the investigators found that 38.2% of patients underwent aortic intervention, mainly for aneurysmal degeneration, with a 6.2% rate of 30-day operative mortality. Two-thirds of procedures were open surgical intervention and the remainder were endovascular therapy. After dividing their series into those who required intervention versus those who did not, the investigators found no difference in the groups based on demographics (age, sex, race, and presence of comorbidities).
The investigators determined that four anatomic predictors for intervention included: (1) an entry tear > 10 mm,(2) total aortic diameter > 40 mm at presentation, (3) false lumen diameter > 20 mm, and (4) an increase in total aortic diameter > 5 mm between serial imaging studies. In addition, the investigators noted that complete thrombosis of the false lumen was protective against late operative intervention.
In the SVS press release, Dr. Conrad commented, “It is clear from the literature that TEVAR is effective in managing patients with acute complicated TBAD by improving aortic remodeling. It is intuitive that this therapy may be beneficial for uncomplicated cases if we can understand who is at high risk for future aortic-related complications. This study suggests that patients whose aortas meet these anatomic criteria may benefit from elective TEVAR 14 to 90 days after presentation.”
Although this retrospective study cannot fully define the role of TEVAR in uncomplicated acute TBAD, it provides evidence for use of anatomic criteria in decision-making in these complicated cases, advised the SVS announcement.