Tai-Wei Chen
Current Position
Attending surgeon of Cardiovascular Surgery division of Taipei Veterans General Hospital
Lecturer of Medicine Faculty of National Yang Ming Chiao Tung University
Abdominal Aorta & Aortic iliac Session

Topic: Use of chimney grafts in the treatment of pararenal aortic pathologies: Hazardous or useful?


Objects and Methods: The chimney stent technique was initially introduced to rescue accidentally covered aortic branches during aortic endovascular repair. Nevertheless, the prevailing evidence extends the use of chimney graft in endovascular pararenal aortic pathologies repair (ch-EVAR) for extending proximal sealing zones. In this study, we retrospectively collected 37 patients between 2012-2018, who underwent ch-EVAR in our hospital for para-renal abdominal aortic aneurysms repair, with at least one renal chimney stent.
Postoperative computed tomography was analyzed by centerline reconstruction to confirm the take-off of renal arteries, chimney stent orientation, chimney stent angulation and chimney stent overlapping length.
scans. Early type IA endoleaks were defined as evidence of a perigraft flow channel within the proximal seal zone.
Results: In our study, 45 renal chimney stents were analyzed, with 25 stent grafts (SG) and 20 bare metal stents (BS) being used. The mean follow-up time 28.2 months, and two “gutter” type Ia endoleaks (4.4%) were identified. During follow-up, one endoleak resolved without intervention, with the other treated by consequent proximal extension stent grafting with concomitant chimney stent extension. The early patency of chimney stent was high (97%) and remained high during follow-up (89.9% at 36 months), and no significant difference was identified of patency between SG and BS group. There was a trend of potential chimney stent occlusion correlated to longer overlapping length between chimney stent and aortic stent, larger orientation and angulation of chimney stents, though no statistically significance was found.
Conclusions: Our study support the benefit of chimney stent techniques in the treatment of para-renal aortic pathologies. In particular, the low early complication rates and high mid-to long-term patency seem advantageous. The chimney technique is valuable for selected patients with complex aortic pathologies, and the orientation and overlapping length of chimney stent shall be considered cautiously to avoid early stent occlusion.