The Clinical Impact of the Spring Back Force of the Bending Frozenix Produced Open Stent-graft

Katsukiyo Kitabayashi, Masayuki Sakaki, Takashi Murakami

Osaka National Hospital, Osaka, Japan

Date, time and location: 2018.05.26 15:30, Exhibition area, 1st Floor. Zone – A

Abstract

Background) Although frozen elephant trunk (FET) is an accepted option in total arch replacement (TAR) for the patients of aortic dissection, stent graft induced new entry (SINE) was arising as a new complication.Chronic phase of dissection and graft oversizing were reported as risk factors of SINE in the usual endovascular technic. However, even with optimal graft size, SINE occurred at major curvature of aorta in the patients of FET. It was supposed to be caused by spring back force (SBF) of metal stent. This time we examine SBF of Frozenix open stent graft, which is the only stentgraft available for open surgery in Japan, and compared it to cTAG stentgraft used in endovascular technic. We also examine the clinical aspect of SBF of Frozenix in computed tomography of the patients.

Method) SBF of 60°bending Frozenix open stentgraft (every different size) at 2, 4, 6cm points was measured. And compared it to the SBF of cTAG measured in the same way. We examine the angle and length of the distal part of Frozenix in postoperative computed tomography of the patients undergone TAR+FET.

Result) SBF of Frozenix is especially higher at 2cm than 4, 6cm point, and not depends on graft size. It is much higher than similar size of cTAG. Since 2015, we performed TAR+FET in 18 patients. And 5 of them are for aortic dissection. Two cases of them were undergone additional TEVAR for the distal part. One had the 20mm, 90°bending of the Frozenix. The SINE occurred 10 months after TAR+FET, and urgent TEVAR was performed. Another case had 20mm, 45° bending and prophylactic TEVAR was performed. The other three cases had more than 4cm straight landing zone.

Conclusion) We should be more careful to get at least 4cm straight landing zone in TAR+FET with Frozenix, than the usual endovascular procedure with cTAG.