INSTEAD-XL Studies Long-Term Benefit of TEVAR for Type B Aortic Dissection

August 6, 2013—Christoph A. Nienaber, MD, et al published the findings from the INSTEAD-XL study online ahead of print in Circulation: Cardiovascular Interventions (CCI).

In this study of survivors of type B aortic dissection, the investigators concluded that thoracic endovascular aortic repair (TEVAR) in addition to optimal medical treatment is associated with improved 5-year aorta-specific survival and delayed disease progression, and in stable type B dissection with suitable anatomy, preemptive TEVAR should be considered to improve late outcome.

The investigators noted that the background of the study is that TEVAR represents a therapeutic concept for type B aortic dissection but that long-term outcomes and morphology after TEVAR for uncomplicated dissection are unknown.

As summarized in CCI, 140 patients with stable type B aortic dissection previously randomized to optimal medical treatment and TEVAR (n = 72) versus optimal medical treatment alone (n = 68) were analyzed retrospectively for aorta-specific and all-cause outcomes, as well as disease progression, using landmark statistical analysis of years 2 to 5 after the index procedure. Cox regression was used to compare outcomes between groups; all analyses are based on intention to treat.

The investigators found that the risk of all-cause mortality (11.1% vs 19.3%; P = .13), aorta-specific mortality (6.9% vs 19.3%; P = .04), and progression (27% vs 46.1%; P = .04) after 5 years was lower with TEVAR than with optimal medical treatment alone. Landmark analysis suggested a benefit of TEVAR for all endpoints between 2 and 5 years; for example, for all-cause mortality (0% vs 16.9%; P = .0003), aorta-specific mortality (0% vs 16.9%; P = .0005), and progression (4.1% vs 28.1%; P = .004). Landmarking at 1 year and 1 month revealed consistent findings. Both improved survival and less progression of disease at 5 years after elective TEVAR were associated with stent-graft-induced false lumen thrombosis in 90.6% of cases (P < .0001), reported the investigators in CCI.