Protocol for GUo's renovisceral Artery reconstruction-1: a prospective, multicentre, single-arm clinical trial to evaluate the safety and efficacy of a multibRANched sTEnt graft systEm for thoracoabdominal aortic aneurysm (GUARANTEE study)

Off the Shelf Multibranched Endograft for Thoraco-Abdominal and Pararenal Abdominal Aortic Aneurysms: a Prospective, Single Centre Study of the G-Branch Endograft

OBJECTIVE

To investigate outcomes of a novel, off the shelf multibranched endovascular stent graft for the treatment of thoraco-abdominal aortic aneurysm (TAAA) and pararenal abdominal aortic aneurysm (PAAA).

METHODS

A prospective, single centre study including 15 patients (mean age, 63.4 ± 10.7 years; 13 male) with TAAA or PAAA treated from October 2019 to March 2021 with a G-Branch endograft (Lifetech Scientific, Shenzhen, China) featuring a mixed multibranch design with two inner and two outer branches for reconstruction of the visceral and bilateral renal arteries, respectively. Follow up assessments were scheduled before discharge and at 30 days, six and 12 months after the index procedure. Annual telephone interviews were performed beyond the initial 12 months. The Kaplan-Meier method was used to estimate cumulative mortality and morbidity rates after endovascular repair.

RESULTS

Technical success was achieved in all 15 patients. Nine patients (60%) had TAAA and six (40%) had PAAA (mean maximum aneurysm diameter, 73.7 ± 15.8 mm). The median follow up was 31.4 months (range, 10.1 - 44.0 months). At 30 days, there was no death and 7% morbidity (one case of temporary spinal cord ischaemia on Day 4). At one year, the mortality rate was 7% (one death from stroke at 10 months) and morbidity was 13% (one other case of renal function decline at six months). There were no aneurysm dilatations, re-interventions, or access related complications, and two (13%) persistent type II endoleaks. The one year primary branch patency rate was 100% for the four renovisceral arteries in all 13 patients who underwent computed tomography examinations. One patient died of hepatocellular carcinoma 29 months post-operatively, resulting in an estimated three year mortality rate of 13%.

CONCLUSION

The G-Branch endograft yielded high technical success with good early and midterm outcomes for the treatment of TAAA and PAAA. A large multicentre study is warranted.

Aortic hemodynamic and morphological analysis before and after repair of thoracoabdominal aortic aneurysm using a G-Branch endograft

Background and objective: The G-Branch endograft is a novel multibranched "off-the-shelf" device used to repair thoracoabdominal aortic aneurysms (TAAAs). This report describes the hemodynamic and morphological performance of the G-Branch endograft in a human patient with TAAA. Materials and methods: We retrospectively reviewed the computed tomography angiography scans and clinical data of a woman in whom TAAA was treated using a G-Branch endograft. Patient-specific three-dimensional models were reconstructed, and computational fluid dynamics and morphological and hemodynamic indicators were analyzed before and after implantation of the device. Results: From a morphological perspective, there was an increase in cross-sectional area in the G-Branch endograft and all bridging stent grafts over time. Blood flow was redistributed among the renovisceral arteries, with a decrease in flow rate in the celiac artery and an increase in the left renal artery. Laminar blood flow was smoother and more rapid after implantation of the G-Branch device and remained stable during follow-up. In the bridging stent grafts, flow recirculation zones were found in the bridging zones of the celiac artery and superior mesenteric artery as well as the distal sealing zones of both renal arteries. Furthermore, higher time-averaged wall shear stress and a lower oscillatory index and relative resident time were found in the G-Branch endograft and bridging stent grafts. Quantitative analysis showed obvious reduction in the surface area ratio of the elevated time-averaged wall shear stress area and surface area ratio of the relative resident time after G-branch implantation. Conclusion: The revascularization of branch vessels occurred following G-branch implantation, with improvements arising not only from morphological changes but also from hemodynamic alterations. The long-term performance of the G-Branch endograft needs further investigation and clinical validation.