Thoracic Endovascular Aortic Repair on Zone 2 Landing for Type B Aortic Dissection

Although thoracic endovascular aortic repair (TEVAR) is an effective treatment for both complicated and uncomplicated type B aortic dissection (TBAD), the occurrence of retrograde type A aortic dissection (RTAD) after TEVAR could be a disastrous complication. The aim of this study was to examine the safety of zone 2 TEVAR in the treatment of acute and subacute TBAD.

A Relay stent graft (SG) was placed proximally beyond the left subclavian artery (LSA) as zone 2 TEVAR for complicated or uncomplicated TBAD. LSA was preserved by physician-modified fenestrated TEVAR (F-TEVAR) if anatomically possible or by surgical reconstruction of debranching TEVAR (D-TEVAR) if necessary. Otherwise, LSA was simply covered. Changes in the aortic diameters after TEVAR were evaluated using CT scanning.

Between 2013 and 2017, 22 patients (mean age: 63 ± 14 years; 16 males) with TBAD were treated with zone 2 TEVAR. Emergency TEVAR was performed in 9 patients (41%) for complicated TBAD, and elective TEVAR was performed in 13 patients (59%) for uncomplicated TBAD in subacute phases. LSA was preserved in 16 patients via 15 F-TEVAR and 1 D-TEVAR and intentionally covered in 6 patients on emergency TEVAR. Elective TEVAR succeeded in the preservation of LSA flow in all patients (emergency 33% vs. elective 100%; P < 0.01). There were no TEVAR-related complications such as stroke, spinal cord ischemia, and RTAD. Thirty-day mortality was 0%. Aortic remodeling as the expansion of true lumen and shrinkage and complete thrombosed occlusion of false lumen were prominent at the level of SG placement 12 months after TEVAR. During the follow-up period, stent-induced new entry at the distal edge of the SG occurred in 1 patient (4%); however, there was no case of aorta-related mortality.

Zone 2 TEVAR for acute and subacute TBAD might be promising for the prevention of RTAD.