Strategies for subacute/chronic type B aortic dissection: the Investigation Of Stent Grafts in Patients with type B Aortic Dissection (INSTEAD) trial 1-year outcome.

OBJECTIVE: Endovascular stent grafting represents a novel concept for type B aortic dissection both in the acute and subacute/chronic setting, with an unknown effect on outcomes.

METHODS: In a prospective trial 140 patients with stable type B dissection were randomly subjected to elective stent-graft placement in addition to optimal medical therapy (n = 72) or to optimal medical therapy (n = 68) with surveillance (arterial pressure according to World Health Organization guidelines ≤ 120/80 mm Hg). The primary end point was 1-year all-cause mortality, whereas aorta-related mortality, progression (with need for conversion or additional endovascular or open surgical intervention), and aortic remodeling were secondary end points.

RESULTS: There was no difference in all-cause mortality: cumulative survival was 97.0% ± 3.4% with optimal medical therapy versus 91.3% ± 2.1% with thoracic endovascular aortic repair (P = .16). Moreover, aorta-related mortality was not different (P = .42), and the risk for the combined end point of aorta-related death (rupture) and progression (including conversion or additional endovascular or open surgical intervention) was similar (P = .86). Three neurologic adverse events occurred in the thoracic endovascular aortic repair group (1 paraplegia, 1 stroke, and 1 transient paraparesis) versus 1 episode of paraparesis with medical treatment. Finally, aortic remodeling (with true-lumen recovery and thoracic false-lumen thrombosis) occurred in 91.3% with thoracic endovascular aortic repair versus 19.4% with medical treatment (P < .001), which is suggestive of continued remodeling.

CONCLUSIONS: In survivors of uncomplicated type B aortic dissection, elective stent-graft placement does not improve 1-year survival and adverse events, despite favorable aortic remodeling.