FROZENIX FACTS

Pitfalls in the use of FROZENIXin conjunction with total arch
replacement
Department of Cardiovascular Surgery, Tokyo Medical University

Hitoshi Ogino, M.D., Ph.D.

The recent advancement of total arch replacement (TAR) with

Subsequently, TEVAR was scheduled for dilatation of thea frozen elephant trunk (FET) procedure has been widelyfalse channel of the descending aorta (Fig. 2), after which theadopted as a single-stage open aortic repair technique for astenosis of the non-stented segment disappeared, presumably

non-dissecting arch aneurysm with a downstream extension

because of the potential distension of the Dacron graft, asor a first-stage procedure, followed by a second descending

observed on the CT scans before TEVAR (Fig. 2). Anotheraortic replacement or thoracic endovascular aortic repair

institute reported a similar event (Fig. 3), in which case(TEVAR). Compared with the conventional elephant trunk

TEVAR was performed to relieve the stenosis. To prevent(ET) procedure, the FET procedure is also a useful additional

this pitfall, the proximal non-stented segment of FROZENIXTAR procedure in cases of acute and chronic type A or B

should be shortened as much as possible (1–2 cm), with theaortic dissection; in such cases, FET is used to reinforce thedistal anastomosis of TAR suture line placed immediately

distal anastomosis of the TAR and close the false channel

proximal to the stented segment.

of the descending aorta. However, some pitfalls in theperformance of this technique with FROZENIX have beenFig. 1

identified.

PITFALLS IN THE USE OF FROZENIX
1) Kinking of the non-stented segment. FROZENIX comprises
two distinct structural segments: a distal stented segment,
and a proximal non-stented segment. We experienced somekinking of the proximal non-stented segment of FROZENIX
during TAR for acute type A aortic dissection in a 46-yearold male patient who presented with a small intimal tear at
the branching site of the left subclavian artery. TAR with FET
was performed using a 26-mm woven Dacron multi-brancharch graft and 27-mm × 6-cm FROZENIX. Malperfusion of
the bilateral lower extremities was recognized during surgery,and an extra-anatomical bypass comprising an 11-mm woven
Dacron graft between the ascending aorta and the rightfemoral artery was added. Although the postoperative course
was uneventful, the postoperative computed tomography(CT) scans showed some stenosis of the proximal non-stented
segment of FROZENIX (Fig. 1).

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FROZENIX FACTS

Fig. 2

Fig. 3

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FROZENIX FACTS

2) Proximal dislodgement of the distal edge. A moderate

due to a type-Ib endoleak, which was caused by proximal

radial force placed on the inside stent of FROZENIX could

dislodgement of the distal stented segment of FROZENIX.

potentially dislodge the distal edge of the stented segment. In

Emergency TEVAR was performed successfully (Fig. 5).

addition, during TAR with FET, the proximal site of the FET is

In the initial TAR with FET, the FROZENIX appeared

fixed tightly with anastomotic sutures. Consequently, proximal

to be too short to allow sufficient fixation to the descending

dislodgement of the distal stented part of the FROZENIX

aorta, particularly as this case involved a larger fusiform

tends to occur in cases with a larger, fusiform-type aneurysm

arch aneurysm. To prevent this pitfall, FROZENIX withand a relatively short or poor landing zone. Here we describea sufficiently long distal stented part should be used withan 80-year-old male patient with a fusiform distal archendoscope as long as possible to assess the distal landing

aneurysm diameter of 75 mm (Fig. 4). This patient underwent

zone in the descending aorta. Currently, our practice uses 12-TAR with FET using a 26-mm woven Dacron multi-branch

cm FROZENIX devices almost routinely for non-dissecting

graft and 27-mm × 9-cm FROZENIX (Fig. 4). Although hisarch aneurysms, and 9-cm devices for cases of acute aortic

postoperative course was uneventful, within three months

dissection.

he developed an impending rupture of the arch aneurysm

Fig. 4

Fig. 5

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FROZENIX FACTS3) Spinal cord injury. Spinal cord (SC) injury remains one ofTAR with FET using FROZENIX for chronic type A aortic

the most serious sequelae after TAR with FET, with recent

dissection. In this case, the air remained around the FET in thereports describing incidence rates of 5%–10%. The majority

aneurysmal sac even 10 days postoperatively. Although thisof cases are attributable to coverage of the responsible

patient did not suffer from a SC injury, the case suggests theintercostal arteries (ICA), particularly below the T8 level,

potential risk of air embolism of the ICA in cases of SC injury

by the FET, although distal embolization of the ICAs may

consequent to TAR and FET. To prevent this phenomenon,

be responsible in some cases. At our institution, we haveair removal should be ensured carefully before tying theexperienced only one patient with paraparesis, in which thesuture of the distal anastomosis. In our practice, this step isdistal end of FROZENIX was fixed at the T6 level and theperformed routinely via puncture with a small needle after

condition of the descending aorta was not severe. Fortunately,distal anastomosis.

the patient recovered from paraparesis following routine
treatment (e.g., cerebrospinal fluid drainage, norepinephrinefor high blood pressure, steroids). Fig. 6 presents interesting
postoperative CT findings in another patient who underwentFig. 6Higashishinagawa, Shinagawa-ku, Tokyo 140-0002 Japan
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2021-07-00-01