RCT

INSTEAD-XL

Endovascular Repair of Type B Aortic Dissection: Long-Term Results of the Randomized Investigation of Stent Grafts in Aortic Dissection Trial

Circulation: Cardiovascular Interventions, 2013 · Randomized controlled clinical trial with 5-year follow-up (n=140)

Clinical question

Does thoracic endovascular aortic repair (TEVAR) combined with optimal medical therapy improve 5-year aorta-specific survival compared with medical therapy alone in stable uncomplicated Type B dissection?

Population: Patients with subacute or chronic uncomplicated Stanford Type B aortic dissection
Intervention: TEVAR plus optimal medical therapy
Comparator: Optimal medical therapy alone
Primary outcome: All-cause mortality and aorta-specific mortality at 5 years
Result: At 5 years, aorta-specific mortality was significantly lower with TEVAR (6.9% vs 19.3%, P=0.04) and progression of aortic disease was significantly reduced (27.0% vs 46.1%, P=0.04). Complete false lumen thrombosis was achieved in 91.3% with TEVAR vs 19.4% with medical therapy (P<0.001).

What the trial found

Prophylactic TEVAR combined with optimal medical therapy in selected patients with stable Type B dissection was associated with improved 5-year aorta-specific survival (6.9% vs 19.3% mortality) and delayed disease progression (27.0% vs 46.1%).

Current guideline position

Current guidance (2022 ACC/AHA; 2024 ESC): initial medical therapy is foundational for uncomplicated acute Type B dissection, and intervention is indicated for complicated Type B dissection, generally favoring TEVAR when anatomy is suitable. ACC/AHA 2022 describes considering endovascular management in selected uncomplicated Type B dissection with high-risk anatomic features (maximal aortic diameter >40 mm, false-lumen diameter >20-22 mm, primary entry tear >10 mm or on the lesser curve) as an individualized, shared decision. ESC 2024 separately recommends TEVAR in the subacute phase for uncomplicated Type B dissection with favorable endovascular anatomy (Class IIa, Level B), and describes patients with high-risk anatomical features as candidates for individualized pre-emptive TEVAR without publishing the same specific millimeter cutoffs in its accessible text — a high-risk feature is not by itself an automatic TEVAR indication under either guideline.

Clinical interpretation

INSTEAD-XL showed that prophylactic TEVAR added to optimal medical therapy in selected, stable patients with favorable-anatomy uncomplicated Type B aortic dissection was associated with improved 5-year aorta-specific survival and delayed disease progression in the population studied. This is foundational RCT / long-term follow-up evidence, not a guideline: it supports individualized consideration of pre-emptive TEVAR in selected high-risk patients, but does not mean every uncomplicated Type B dissection should receive TEVAR — medical therapy remains the default foundational strategy for uncomplicated disease.

Clinical Context & Relevant Topics (1)

Disease Reference

Acute Aortic Syndromes

Emergency classification, anti-impulse medical stabilization, and surgical vs endovascular management of aortic dissection, intramural hematoma, and penetrating atherosclerotic ulcer.

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