Covering Anastomosis to Frozen Elephant Trunk in Secondary Downstream Aorta Replacement

Abstract

There has been an increasing number of secondary downstream aorta replacements following aortic arch repair using a frozen elephant trunk (FET). We present an anastomosis technique to join a frozen elephant graft to a downstream prosthetic graft. The FET is inserted into the downstream graft with continuous sutures, with a two-bite Dacron graft added to the frozen elephant side. This technique may prevent anastomotic leakage between two grafts.

Keywords

aortic replacement - total arch replacement - prosthetic graft - FET stent graft

As the number of secondary aortic repairs following initial aortic procedures using a frozen elephant trunk (FET) increases,[1] there are more opportunities to anastomose a prosthetic graft to an FET stent graft. We propose an anastomotic technique to avoid anastomotic failure and stabilize the anastomosis.

Techniques and Results

Informed consent was obtained for the academic presentation of this case.

A 50-year-old male with a history of ascending aortic replacement due to acute Type A aortic dissection (at age 27), thoracic endovascular repair (TEVAR; at age 31), abdominal endovascular repair (EVAR; at age 36), and redo Bentall with toral arch replacement using FET (J Graft FROZENIX: Japan Lifeline Co, Tokyo, Japan, [Fig. 1]; at age 48) presented to our department with back pain. Computed tomography showed ruptured acute Type B aortic dissection with triple-barrel aorta posterior mediastinal hemorrhage and bloody pleural effusion ([Fig. 2]).

Fig. 1 Frozenix® (Japan Lifeline Co, Tokyo, Japan). Dacron polyester fabric vascular prosthesis supported by Nitinol stents affixed on the inner aspect.

Fig. 2 Preoperative computed tomography. Ruptured acute type B aortic dissection with triple-barrel aorta and posterior mediastinal hemorrhage and pleural effusion. The arrow showed a rupture site of the descending aorta.

We performed emergency descending aortic replacement surgery.

Under general anesthesia, the patient's left chest was opened at the fourth intercostal space. Cardiopulmonary bypass was initiated with cannulated femoral artery and venous femoral vein cannulation. The proximal descending aorta and distal descending aorta were clamped, and the aorta was opened. After the TEVAR stent graft was removed, the proximal clamp was moved to the FET graft.

The proximal anastomosis was performed as follows. A prosthetic graft (Triplex, Terumo, Japan) of 22 mm diameter was placed over the outside of the FET graft (23 mm diameter). At first, the overlay of the FET graft into the outer graft was 2 cm in length ([Fig. 3A]). After covering the graft, continuous sutures using 4/0 prolene were performed, and the depth of the stitches at the FET graft side were limited to prevent stitches crossing over the stent material ([Fig. 3B]). After this proximal anastomosis, the distal anastomosis was performed in a double-barrel fashion with continuous sutures ([Video 1], available in the online version). The postoperative computed tomography showed no leak from anastomosis ([Fig. 4]) and the postoperative course was uneventful, and the patient was healthy 8 months postoperatively.

Fig. 3 Anastomosis between the frozen elephant trunk (FET) graft and downstream aortic graft. (A) FET graft was inserted into the downstream aortic graft. (B) The downstream graft was sewn with a continuous suture to the FET. Care was taken to limit the depth of the stitches at the FET graft side to prevent stitches from crossing around the stent material.

Fig. 4 Postoperative computed tomography.

Video 1 Covering anastomosis to frozen elephant trunk.

We believe the overlap of grafts contributes to hemostasis and limits the potential for anastomotic leak or fistula.

Discussion

The FET procedure has been widely used globally in patients with aortic dissection[2] or atherosclerotic aneurysm. This technique can cover extended aortic arch pathologies including those of the descending aorta.[3] Moreover, the number of secondary operations after FET surgery has increased.[1] To treat mega-aortic syndrome, staged repair using FET as the first stage has been reported.[4] Since a Japan-made FET prosthesis (J graft Frozenix, Japan LifeLine, Tokyo, Japan) was first launched in 2014, >12,000 prostheses have been implanted. This prosthesis comprises a Dacron polyester fabric vascular prosthesis supported by Nitinol stents affixed on the inner aspect. The Nitinol stents are entirely covered by the Dacron prosthesis and are fixed to the end of the prosthesis. At the secondary descending or thoracoabdominal aortic replacement, an FET graft can be used as a proximal graft for anastomosis to the new extension graft. However, the sutures can be cut by the point of the Nitinol stent that contacts the suture line; therefore, long-term durability is unclear.

Various techniques to anastomose a prosthetic graft to a stent graft have been published.[5] By placing the distal vascular prosthesis over the FET graft, continuous sutures can be stitched only to the outer FET Dacron graft without crossing over the Nitinol stent; therefore, this technique may avoid cutting the stitch. The second advantage is to make the anastomosis easy and stable. Usually, the aortic arch graft is bigger than the descending aortic graft in diameter. When the larger FET graft is anastomosed to the smaller graft in an end-to-end fashion, it is usually compromised by the radial force of the FET graft, and bleeding may occur. By inserting the bigger stent graft into the smaller conventional graft, the radial force contributes to the fixation of the anastomosis, and stability is enhanced. Hemostasis is readily achieved. However, this technique cannot be applied to grafts with metal struts on the outside. The limitation is the size discrepancy between the stent graft and the conventional graft. In our experience, this technique could be performed if the FET graft was less than 5 mm bigger in diameter than the distal graft. However, if a bigger size discrepancy between these two grafts occurs, this technique might be impossible. Another limitation is that this technique cannot be applied to grafts with metal struts on the outside.

Conflict of Interest

A.Y. is a consultant for Japan Lifeline Co., Ltd. All other authors declared no conflict of interest.

Acknowledgment

We would like to thank Ena Yoshitake for creating the illustrations.

• References

• 1 Folkmann S, Weiss G, Pisarik H, Czerny M, Grabenwoger M. Thoracoabdominal aortic aneurysm repair after frozen elephant trunk procedure. Eur J Cardiothorac Surg 2015; 47 (01) 115-119 , discussion 119
• 2 Yoshitake A, Tochii M, Tokunaga C. et al. Early and long-term results of total arch replacement with the frozen elephant trunk technique for acute type A aortic dissection. Eur J Cardiothorac Surg 2020; 58 (04) 707-713
• 3 Tokunaga C, Kumagai Y, Chubachi F. et al. Total arch replacement using frozen elephant trunk technique with Frozenix for distal aortic arch aneurysms. Interact Cardiovasc Thorac Surg 2022; 35 (01) ivac038
• 4 Gkremoutis A, Zierer A, Schmitz-Rixen T. et al. Staged treatment of mega aortic syndrome using the frozen elephant trunk and hybrid thoracoabdominal repair. J Thorac Cardiovasc Surg 2017; 154 (06) 1842-1849
• 5 Matsuo S, Oda K, Motoyoshi N, Saiki Y. Modified cuffed anastomosis technique to treat pseudoaneurysms following thoracic endovascular aortic repair. Interact Cardiovasc Thorac Surg 2012; 14 (05) 677-679

Publication History

Received: 10 December 2023

Accepted: 10 October 2024

Article published online:
17 February 2025