The J Graft Open Stent Graft (JOSG) (Japan Lifeline Inc., Tokyo, Japan) (Fig. 1) was commercialized in 2014 in Japan  and is applied using the frozen elephant trunk (FET) technique for extensive aortic arch aneurysm and aortic dissection. In aortic dissection, the FET is used for closing the entry of the descending aorta, securing flow of the true lumen and decreasing the pressure of the false lumen, which may promote thrombosis of the false lumen. The E-vita OPEN PLUS (Jotec Inc., Hechingen, Germany) and Thoraflex Hybrid (VASCUTEK Ltd., Scotland, UK) have been used in Western countries with good results [2, 3]. Similarly, although the JOSG has different characteristics compared with other open stent grafts, good early outcomes after total arch replacement (TAR) with the FET using the JOSG for acute Type A aortic dissection have been reported . However, some adverse events are associated with this procedure, requiring additional interventions [1–4]. Kinking of the JOSG is rare . We describe 2 patients who developed kinking of JOSGs after TAR with the FET for acute Type A aortic dissection.
Case 1 was a 44-year-old man, who was transferred to our hospital because of chest pain. Computed tomography (CT) angiography showed acute Type A aortic dissection that consisted of entry of the ascending aorta and large re-entry of the descending aorta with compression of the true lumen by a patent false lumen. Therefore, he underwent translocated TAR with the FET emergently. After TAR, transoesophageal echocardiography detected kinking of the JOSG. We then performed a remodelling root procedure because of aortic root rupture near the left coronary artery ostia and aorto-left femoral artery bypass to maintain blood flow of the lower body. After the operation, our patient developed intermittent claudication. CT angiography showed kinking between the non-stent and stent parts of the JOSG due to a severely angulated arch (Fig. 2A). This required additional endovascular repair. After endovascular repair, CT angiography showed an expanded lumen of the JOSG (Fig. 2B).
Case 2 was a 30-year-old man, who had annuloaortic ectasia and moderate aortic valve regurgitation with Marfan syndrome. CT angiography showed acute Type A aortic dissection from the aortic root to the thoraco-abdominal aorta with entry of the ascending aorta and a patent false lumen. Therefore, we performed a reimplantation root procedure and translocated TAR with the FET emergently. After the operation, he had decreased blood pressure in the lower body and intermittent claudication. CT angiography showed kinking between the non-stent and stent parts of the JOSG caused by a severely angulated arch (Fig. 2C). We then performed additional endovascular repair, which improved kinking of the JOSG (Fig. 2D).
Coarctation or kinking of an open stent graft after TAR with the FET is a rare adverse event. Uchida et al.  reported kinking between the non-stent and stent parts of the JOSG for a sharply bending aorta. We also experienced 2 patients who developed kinking of the JOSG between the non-stent and stent parts after TAR with the FET for acute Type A aortic dissection. A risk of kinking may be a severely angulated arch in acute aortic dissection, which is associated with a relatively young age. Moreover, translocated TAR may aggravate this adverse event due to preservation of the curve of the aortic arch, instead of achieving haemostasis. Uchida et al.  recommended that the stent part should sufficiently cover the aortic arch, and the non-stent part should be kept as short as possible to protect the stent graft from kinking. E-vita OPEN PLUS and Thoraflex may prevent kinking of open stent grafts in severely angulated arches because these open stent grafts have no non-stent parts between the distal anastomosis site and the stent [2, 3]. However, the JOSG has an inner stent made of nitinol wire with a soft woven graft, which reduces injury to the intima. This is different from other commercialized open stent grafts, such as E-vita OPEN PLUS, which consists of an outer stent. The inner stent end boundary between the non-stent soft woven graft and the stent may easily lead to kinking by an angulated arch compared with other open stent grafts. Therefore, in translocated TAR with the FET for acute aortic dissection, the removed non-stent part of the JOSG should be as short as possible to prevent kinking of the JOSG.
We thank Ellen Knapp from Edanz Group (www.edanzediting.com/ac) for editing the draft of this article.
Conflict of interest: none declared.