Highlighting Recent Research: The Impact of TEVAR on Long-Term Survival in Type B Aortic Dissection

Research recently published in The Annals of Thoracic Surgery retrospectively compares outcomes of treatments for dissection of the descending thoracic or thoracoabdominal aorta. Current standard of care for type B aortic dissection (TBAD) depends on whether or not a patient presents with complications such as malperfusion or rupture. While acute repair is indicated for individuals with complicated TBAD, the first-line therapy for uncomplicated acute TBAD is aggressive hypertension control, termed optimal medical therapy (OMT). For patients with uncomplicated TBAD, dissection repair is not recommended unless the dissection worsens to avoid unnecessary costs and surgical complications in patients who may not ever require dissection repair. While short-term outcomes of this approach are excellent, reported intervention-free survival is only 63% at 5 years¹ or 41% at 6 years.² Reports of overall survival are similarly discouraging, 75% at 3 years³ and ranging from 60 to 80% at 5 years.⁴ These poor long-term outcomes call into question the decision to delay dissection repair when TBAD is otherwise uncomplicated.

Dr Bradley Leshnower, senior author of the study.

To better understand the natural history of TBAD outcomes, Lou and colleagues reviewed data from 398 patients presenting with acute TBAD over 16 years.⁵ Patients with complicated acute TBAD underwent thoracic endovascular aortic repair (TEVAR) at their initial diagnosis, while patients with uncomplicated TBAD received OMT initially. Patients with uncomplicated TBAD were grouped based on their final treatment strategy: open surgical repair, TEVAR, or continued OMT. The authors found poor long-term outcomes for all uncomplicated TBAD patients: 58.9% overall survival and 30.9% intervention-free survival at 10 years. Dr Bradley Leshnower, the senior author, says of the study, “the most surprising findings were the poor long-term outcomes observed in the patients with uncomplicated TBAD and the excellent long-term outcomes of the patients who presented with complicated TBAD….Patients [with complicated TBAD] who were treated with TEVAR at the initial diagnosis had a 10-year survival of 84.1%, despite being a high risk cohort of patients.”

Over the 16-year period retrospectively studied by Lou and colleagues, endovascular therapy for TBAD evolved into a more aggressive treatment strategy where endograft coverage routinely extended from the left subclavian to the celiac artery. Dr Leshnower emphasized that this shift in treatment strategy did not temper the observation of improved long-term results with early endovascular repair. “There are two ‘take home messages’ from our study,” says Dr Leshnower. “First, OMT for uncomplicated acute TBAD results in poor long-term results. Second, patients treated with TEVAR in the acute phase of TBAD had improved long-term survival compared to patients treated with definitive OMT or delayed TEVAR. Based upon the results of (our) study and others, management of uncomplicated TBAD will become more aggressive in the future, with endovascular therapy replacing OMT for the vast majority of patients.”

This study adds to the knowledge gained from recent trials on TBAD treatment. While the ADSORB trial found no difference in mortality between OMT and acute TEVAR after one year,⁶ the data from Lou and colleagues suggests that longer follow-up would reveal improved long-term survival with early TEVAR. The INSTEAD trial demonstrated improved chronic TBAD outcomes with TEVAR compared to OMT,⁷ and the authors’ work complements these findings by suggesting that acute TEVAR intervention provides better TBAD outcomes than TEVAR in the chronic phase. The authors are continuing their research in this area, turning their attention to predictive factors that might help determine when OMT is likely to fail or what characteristics of a primary tear indicate likely aortic growth in TBAD. Such predictive factors will be important considerations for ensuring that aggressive treatment strategies are targeted to the patients who will benefit most from them.

Visit The Annals of Thoracic Surgery to read the full article: The Impact of TEVAR on Long-Term Survival in Type B Aortic Dissection. This study was presented at the Annual Meeting of the Society of Thoracic Surgeons, and audio from the discussion that followed this presentation accompanies the article.

References

1. Afifi RO, Sandhu HK, Leake SS, et al. Outcomes of patients with acute type B (DeBakey III) aortic dissection: A 13-year, single-center experience. Circulation. 2015;132(8):748-754. http://dx.doi.org/10.1161/CIRCULATIONAHA.115.015302.
2. Durham CA, Cambria RP, Wang LJ, et al. The natural history of medically managed acute type B aortic dissection. J Vasc Surg. 2015;61(5):1192-1198. http://dx.doi.org/10.1016/j.jvs.2014.12.038.
3. Tsai TT, Fattori R, Trimarchi S, et al. Long-term survival in patients presenting with type B acute aortic dissection. Circulation. 2006;114(21):2226-2231. http://dx.doi.org/10.1161/CIRCULATIONAHA.106.622340.
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5. Lou X, Chen EP, Duwayri YM, et al. The Impact of Thoracic Endovascular Aortic Repair on Long-Term Survival in Type B Aortic Dissection [published online ahead of print August 12, 2017]. Ann Thorac Surg. http://dx.doi.org/10.1016/j.athoracsur.2017.06.016.
6. Brunkwall J, Kasprzak P, Verhoeven E, et al. Endovascular repair of acute uncomplicated aortic type B dissection promotes aortic remodelling: 1 year results of the ADSORB trial. Eur J Vasc Endovasc Surg. 2014;48(3):285-291. http://dx.doi.org/10.1016/j.ejvs.2014.05.012.
7. Nienaber CA, Kische S, Rousseau H, et al. Endovascular repair of type B aortic dissection: long-term results of the randomized investigation of stent grafts in aortic dissection trial. Circ Cardiovasc Interv. 2013;6(4):407-416. http://dx.doi.org/10.1161/CIRCINTERVENTIONS.113.000463.