2.1 INSTEAD
The INSTEAD (The INvestigation of STEnt Grafts in Aortic Dissection) trial included un-TBAD patients in the subacute and chronic phases. One hundred and forty patients were randomly allocated to two treatment groups. The first group subjected to elective stent-graft placement in addition to OMT (n=72); the second group was assigned to OMT alone (n=68) with BP monitoring. The primary outcome was all-cause mortality at two years. Secondary outcomes included aorta-related deaths (rupture), disease progression(with conversion or additional endovascular or open surgery), and aortic remodelling (FL thrombosis as well as TL and FL diameters). Data over a two-year follow-up period showed no difference between the two groups in all-cause mortality (95.6 ± 2.5% with OMT versus 88.9 ± 3.7% with TEVAR, P=0.15), aorta-related death (97.0 ± 2.0% with OMT versus 94.4 ± 2.7% with TEVAR, P=0.44). However, three neurological complications occurred in the TEVAR group versus only one with medical treatment (30-day, not significant). In addition, there was no difference in incidence of persistent paraplegia/paraparesis and major stroke within two years of randomization (P=0.90 and P=0.53, respectively) More importantly, TEVAR patients showed improved aortic remodelling compared to the OMT group (91.3% and 19.4%, respectively, P<0.001). Collectively, these findings highlighted that despite improved aortic remodelling, TEVAR failed to incur a morbidity and mortality benefit [25].