Early Aortic Repair in patients Needing Endovascular/open Surgery for Type B Aortic Dissection (EARNEST): A randomised trial to assess the clinical and cost-effectiveness of thoracic endovascular aortic repair in the subacute phase after uncomplicated type B aortic dissection.

Research question: In patients with uncomplicated type B aortic dissection (uTBAD), does thoracic endovascular aortic repair (TEVAR) in the subacute phase in addition to best medical therapy (BMT) compared to BMT and surveillance, confer a long-term advantage and is this practice cost effective?

Background: After uTBAD, most patients are treated with BMT consisting of blood pressure control and surveillance. However, approximately 1/3 of patients have late aortic dilatation and require complex surgical procedures to prevent rupture with a high rate of morbidity and mortality. Alternatively, soon after uTBAD, patients can be offered early TEVAR.

This leads to closure of the primary entry tear, promoting thrombosis of the false lumen, allowing positive aortic remodelling, reducing the risk of long-term aneurysm formation and complications, and the need for more complex, potentially highly expensive procedures.

Objective: to test the hypothesis that in patients with uTBAD, TEVAR in the subacute phase confers a long-term advantage over standard care, and that this practice is cost effective.

Primary aim: In uTBAD patients, to determine whether early TEVAR and BMT compared to surveillance and BMT (with late aortic repair only if required) decreases the composite outcome of aortic-related mortality, severe permanent neurological deficit or severe permanent cardiorespiratory failure over 5-years.

Secondary aims: To determine whether early TEVAR is safe, leads to increased rate of aortic remodelling over 1-year; is cost-effective over 5-years; and whether this strategy has lower aortic-related mortality, fewer re-interventions/complications, and has greater quality of life (QoL) over 5-years.

Methods: EARNEST is a multicentre, open label, superiority RCT, randomly allocating consenting patients with uTBAD in the sub-acute phase in a 1:1 ratio to TEVAR and BMT (TEVAR+BMT) or surveillance and BMT (SURV+BMT). It will have adjudicated endpoints and an internal pilot. The study will recruit for 42 months. Each patient will be followed up for 5-years.

470 patients with uTBAD, suitable for TEVAR will be identified from 25 centres and regional network patient identification centres. Randomisation will be stratified for centre, age and sex.

Patients in the TEVAR+BMT group will undergo TEVAR 10 days-3 months after presentation in centres that have been credentialled.

All patients will undergo clinical assessment, blood pressure (BP) monitoring and routine surveillance scanning with CT/MRI at six months, one year and yearly for five years. Data on adverse events, EQ-5D-5L quality of life measures and resource use will be collected at the same time periods.

The patient selected primary outcome measure is a composite outcome of aortic-related mortality, severe permanent neurological deficit, or severe permanent cardiorespiratory failure over five years.

Timelines for delivery: The study will start in October 2023 and last 9.5-years. There will be 6-month set up; 42-month recruitment including 18-month internal pilot; 5-year participant follow up; 6-month analysis/dissemination.

Anticipated impact and dissemination: We expect this trial to provide definitive evidence on the effectiveness of early TEVAR in patients after uTBAD. The results are expected to inform international guidelines and change practice in the UK and abroad. Disseminated electronically, in written form and via webinars to patients and the public, clinicians, and policy makers.