INSTEAD-XL: TEVAR is superior to medical therapy alone for type B dissections at five years


Results of the INSTEAD-XL, published in Circulation: Cardiovascular Interventions, show that thoracic endovascular aortic repair of uncomplicated type B dissections in addition to medical therapy is associated with improved five-year aorta-specific survival and delayed disease progression. The data from the study were published online on 6 August 2013.

“Thoracic endovascular aortic repair (TEVAR) represents a therapeutic concept for type B aortic dissection. Long-term outcomes and morphology after TEVAR for uncomplicated dissection are unknown,” the authors of INSTEAD-XL (Endovascular repair of type B aortic dissectionlong-term results of the randomized investigation of stent grafts in aortic dissection trial), led by Christoph A Nienaber, Heart Center Rostock, University of Rostock, Rostock, Germany, wrote.

A total of 140 patients with stable type B aortic dissection previously randomised to optimal medical treatment and TEVAR (n=72) vs. optimal medical treatment alone (n=68) were analysed retrospectively for aorta-specific, all-cause outcomes, and disease progression using landmark statistical analysis of years two to five after index procedure. Cox regression was used to compare outcomes between groups; all analyses are based on intention to treat.

The risk of all-cause mortality (11.1% vs. 19.3%; p=0.13), aorta-specific mortality (6.9% vs. 19.3%; p=0.04), and progression (27.0% vs. 46.1%; p=0.04) after five years was lower with TEVAR than with optimal medical treatment alone, the study shows.

Landmark analysis suggested a benefit of TEVAR for all end points between two and five years; for example, for all-cause mortality (0% vs. 16.9%; p=0.0003), aorta-specific mortality (0% vs. 16.9%; p=0.0005), and for progression (4.1% vs. 28.1%; p=0.004); Landmarking at one year and one month revealed consistent findings. Both improved survival and less progression of disease at five years after elective TEVAR were associated with stent graft induced false lumen thrombosis in 90.6% of cases (p<0.0001).

The authors concluded: “In this study of survivors of type B aortic dissection, TEVAR in addition to optimal medical treatment is associated with improved five-year aorta-specific survival and delayed disease progression. In stable type B dissection with suitable anatomy, pre-emptive TEVAR should be considered to improve late outcome.”