2.2 INSTEAD-XL
Nienaber et al. extended the follow-up up period of the INSTEAD RCT to five years. TEVAR was shown to reduce all-cause mortality (11.1% versus 19.3%; P=0.13), aorta related mortality (6.9% versus 19.3%; P=0.04), and progression of dissection (27.0% versus 46.1%; P=0.04) relative to OMT alone. Complete stent graft-induced FL thrombosis was observed in 90.6% of elective TEVAR cases at five years relative to 22.0% with OMT only (P<0.0001). TEVAR was necessary in fourteen cases randomized to OMT alone and seven additional stent grafts were required in the TEVAR group. Furthermore, three TEVAR patients underwent open surgical conversion as well as four cases in the OMT alone group. Events leading to crossover or open conversion occurred more frequently with OMT than after TEVAR. Overall, TEVAR conferred a long-term survival advantage with the Kaplan–Meier curves demonstrating survival benefit (all-cause and aorta-specific mortality) with TEVAR seen between 2 and 5 years (P=0.0003 and P=0.0005, respectively). The authors recommended considering pre-emptive TEVAR in stable patients with suitable anatomy to improve late outcomes [26].