Second-Generation Spider-Graft: Development of the Novel Hybrid Thoracoabdominal Aorticdevice in a Porcine Model

Abstract

Introduction - The SPIDER-graft was developed to avoid thoracotomy, extracorporeal circulation (ECC) and to reduce cross-clamping during thoracoabdominal aortic (TAA) repair time. The first generation reversed Frozen Elephant Trunk with proximal stentgraft for retrograde delivery to the descending thoracic aorta (DTA) and distal abdominal prostheses for open repair with four visceral and two iliac branches was further optimized (modification of the visceral branches and the introducer system) and compared to open aortic repair (OAR) in a pig model. Methods - Retroperitoneal access to the TAA was performed in 6 pigs per group (75-85kg). For OAR TAA exposure was required. After crossclamping proximal and distal aortic anastomosis were performed and successively celiac trunk (CT), superior mesenteric artery (SMA), right and left renal arteries (RA) and finally iliac arteries were implanted. For Spider-graft, retroperitoneal exposure of the infradiaphragmaitc aorta was performed. The right iliac branch was first temporarily anastomosed end-to-side to the distal aorta maintaining periprocedural retrograde visceral and antegrade aortoiliac blood flow. Proximal stent-grafted part was deployed in the DTA via the CT ostium. Visceral and renal arteries were successively anastomosed to the side-branches of the graft and lumbar arteries were reimplanted. Technical feasibility, operating and clamping time, blood flow and tissue perfusion in the related organs were evaluated before implantation and 3, and six hours after implantation using transit-time flow measurement (TTFM) and fluorescent microspheres (FM). After 6 hours observation, final angiography, post-procedural CT-angiography and histology was performed. Results - Graft deployment was successful in all 6 animals in both groups. All pigs were hemodynamically stable during the entire procedure. Total aortic clamping time was 88.3±16.3min during OAR and 4.2±1min during SPIDER-graft. Selective ischemic times of related organs were significantly longer during OAR. TTFM and FM confirmed clinical findings. Angiography and CT-scan confirmed successful graft implantation in both groups. Conclusion - Conclusion: SPIDER-graft can reduce crossclamping time, ischemic time, and avoid ECC and thoracotomy during TAA repair in a pig model. Hemodynamic stability can be achieved easier with less blood loss compared to OAR. The SPIDER-graft will be further modified to improve the handling and to enable reimplantation of lumbar arteries.