Clinically silent early proximal seal failure with suspected interval distal endograft displacement after hybrid zone 2 thoracic endovascular aortic repair in severe arch tortuosity: a case report with 1-year follow-up.

Background: Durable hybrid zone 2 thoracic endovascular aortic repair depends on adequate healthy sealing length, appropriate oversizing, and close endograft apposition. Severe arch tortuosity can compromise these requirements even when completion angiography is satisfactory. Case presentation: A 46-year-old woman with a primary non-post-surgical distal arch and proximal descending thoracic aneurysm underwent left carotid-subclavian bypass, left subclavian artery origin occlusion, and zone 2 thoracic endovascular aortic repair. The reported proximal landing segment was approximately 16 mm, and the proximal aortic diameter was 24.2 mm. Two 28-mm GORE TAG modules were implanted. Completion angiography showed no visible endoleak. Predischarge CTA on postoperative day 9 demonstrated suspected interval distal displacement of the proximal endograft, loss of the proximal seal, and a high-flow type Ia endoleak. An additional 28-mm proximal extension was deployed immediately distal to the left common carotid artery, restoring the seal. Imaging at 1 month, 4 months, and approximately 12 months showed stable endograft configuration, persistent bypass patency, no recurrent endoleak, and reduced radial thickness of the excluded sac. Conclusion: A satisfactory completion angiogram did not exclude early proximal seal failure in this severely tortuous arch with a short zone 2 landing segment. Early postoperative CTA enabled treatment before clinical deterioration. The case supports careful anatomical selection, centreline-based reporting, and early surveillance when standard TEVAR is used outside preferred sealing-zone geometry.