Prophylactic TEVAR Shows Promise for Uncomplicated Type B Aortic Dissection

Prophylactic thoracic endovascular aortic repair (TEVAR) may be a better option than medical therapy for younger patients with potentially catastrophic aortic tears, an observational study suggests. 

“TEVAR should be considered as a therapy for selective patients with uncomplicated type B acute aortic dissection who have long life expectancy,” senior study author Gao-Jun Teng, MD (Zhongda Hospital, Nanjing, China), told TCTMD in an email.

His study, led by colleague Yong-Lin Qin, MD, was an attempt to shed light on endovascular treatment in this patient population because optimal treatment modalities are far less clear than in cases of complicated type B aortic dissections.

Results were published in the June 21, 2016, issue of the Journal of the American College of Cardiology.

TEVAR Better Over the Long Term

The study, conducted at three tertiary medical centers, included 184 patients treated with TEVAR and appropriate medical therapy within 14 days of symptom onset and 154 treated with medical therapy alone. Approximately 45% of patients in both groups had hypertension and were smokers.

In the first 30 days, patients in the medical therapy group had fewer aortic-related events than those in the TEVAR group, although this difference was not significant. Over the long term, however, rates of both adverse events and mortality were substantially better with TEVAR. 

Of the 50 deaths that occurred at 30 days or later, 27 were aortic-related. Most of these were due to a ruptured false lumen in the descending aorta, except for three that were attributed to retrograde type A dissection.

At 5 years, cumulative freedom from aortic-related adverse events was 71.8% in the TEVAR group and 62.2% in the medical therapy group, with more aortic-related adverse events overall in the latter group. Cumulative survival was 89.2% for TEVAR and 85.7% for medical therapy (P = 0.01). Qin and colleagues note that the survival rate for the TEVAR group is better than that seen in previous studies of patients with complicated and uncomplicated type B aortic dissection, which have reported 1- and 5-year survival rates of 83% and 79%, respectively, with TEVAR.

Why Rush?

In an editorial accompanying the study, Christoph A. Nienaber, MD, PhD (Imperial College, London, England), notes that some aspects of the small, chart-review study are controversial. Citing data from the European Registry on Endovascular Aortic Repair Complications, he questions the wisdom of performing TEVAR in the acute phase of symptom onset in uncomplicated type B dissection patients.

“Postponing TEVAR to the subacute phase could have avoided their one case of retrograde dissection while still allowing ample time for TEVAR-induced remodeling before the window of plasticity/opportunity starts closing about day 100,” he writes. “Why rush when the strategy allows for a fully elective TEVAR including neck vessel debranching, if necessary, for an optimal landing zone?”

To TCTMD, Teng said his group disagrees with Nienaber, and believes earlier timing is appropriate for those uncomplicated patients without connective tissue disease. Teng said patients with connective tissue disease (ie, Marfan syndrome or Ehlers-Danlos syndrome), on the other hand, are the ones who have been demonstrated in the literature to be most at risk for retrograde procedure-related dissection when treated with TEVAR. Patients with connective tissue disease were excluded from the current study, he noted.

Importantly, Nienaber also asserts that the study authors neglected to list “both crossovers and missed crossovers from medical management to therapeutic TEVAR or open surgical management during the years of follow-up.” This is potentially important, he notes, because therapeutic TEVAR based on evidence of late progression during follow-up may have prolonged survival for some patients.

“We agree that therapeutic TEVAR used with evidence of late progression during follow-up could have helped some patients survive with aorta-related complications,” Teng acknowledged. He added that while it is a “shortcoming,” reintervention on patients with complications during follow-up was “not closely related to the purpose of our study.”

Overall, Nienaber says although the data confirm the long-term benefit of TEVAR in this patient population, they do not help in better defining “uncomplicated” aortic dissection or stratifying therapy options.

What is needed, he suggests, is “a set of more granular ‘high-risk’ features and criteria to prospectively identify patients for prophylactic TEVAR.”

Sources:

• Qin Y-L, Wang F, Li TX, et al. Endovascular repair compared with medical management of patients with uncomplicated type B acute aortic dissection. J Am Coll Cardiol. 2016;67:2835-2842. 
• Nienaber CA. The art of stratifying patients with type B aortic dissection. J Am Coll Cardiol. 2016;67:2843-2845. 

Disclosures:

• The study was sponsored by the National Key Basic Research Program of China, and Jiangsu provincial special program of medical science. 
• Qin, Teng, and Nienaber report no relevant conflicts of interest. 

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