FROZENIX FACTS

Total aortic arch replacement with frozen
elephant trunk using FROZENIX for residual
aortic dissecting aneurysm after replacing theascending aorta for acute type A aortic dissection
Department of Cardiovascular Surgery, Nagoya University Graduate School of Medicine

Akihiko Usui, M.D., Ph.D.

are exposed using a groin incision. The heart is exposed

INDICATION AND LIMITATION

by median sternotomy. When injury of the aorta or heart isWe principally perform a central repair with total aortic arch

expected, a partial cardiopulmonary bypass is created beforereplacement (TAR) with frozen elephant trunk (FET) using

the sternotomy.

FROZENIX for patients with residual chronic aortic dissecting

After the sternotomy, the innominate vein is dissected andaneurysm after the ascending aorta replacement for acute typetaped first because adhesions around the ascending aorta andA aortic dissection. This procedure can be applied in cases

the heart are usually severe. It is sometimes easy to dissectwith chronic type B aortic dissection that expands to the aortic

around the brachiocephalic artery and left common carotidarch. However, it is sometimes difficult to insert FET into anartery beneath the innominate vein. The removal of adhesions

extremely narrow true lumen of the descending aorta, limiting

inside the pericardium can usually be limited to around thethe applicability of TAR + FET. When the minimum size

right side of the right atrium only to expose the right superior

FROZENIX (21 mm) cannot be inserted into the true lumen,

pulmonary vein in order to insert a left ventricular ventdirect repair of the descending aorta should be considered.

securely. After heparinization, a cardiopulmonary bypass

TAR + FET can manage the proximal entries around theis established with groin cannulation; an outflow cannula

aortic arch or the distal arch, but the distal entries of theis added into the superior vena cava, and core cooling islower descending aorta or thoracoabdominal aorta cannot beapplied. In cases with minor asthelomatous plaque on thetreated. When the descending and/or thoracoabdominal aorta

aortic arch, reconstruction of the arch branches is performed

is severely enlarged, cautious follow-up by CT examination

during cooling. The brachiocephalic artery is simply clamped,is essential after the central repair. When the residual aortictransected, and anastomosed with the main branch of adissection becomes enlarged after the first surgery, direct

trifurcated graft in end-to-end fashion. Thereafter, selective

repair with total descending or thoracoabdominal aortic

cerebral perfusion (SCP) is initiated via the trifurcated graft.

replacement via left thoracotomy should be immediately

The left common artery is also anastomosed with the secondscheduled. Some cases promptly reveal enlargement after thebranch of the trifurcated graft in the same fashion, and SCP isfirst surgery. In such cases, large reentries are generally open

also established.

on the thoracoabdominal aorta.

When the nasopharyngeal temperature reaches 25°C, main
perfusion of the cardiopulmonary bypass is stopped and only
SCP is continued. The aortic arch is transected just above theSURGICAL PROCEDURE

previous distal anastomotic site, and the proximal entries are

In supine position, arterial pressure should be securelyinspected first. Entries are usually placed around the proximal

obtained on both the radial artery and either dorsalis pedis

anastomosis site. The left subclavian artery is clamped at theartery. The left axillary artery is exposed under the subclavian

proximal site or sutured at the orifice, and SCP is added via anincision and an 8-mm ringed artificial graft is anastomosed

8-mm ringed graft anastomosed to it. Cold blood cardioplegia

to it in end-to-side fashion. The right femoral artery and vein

is antegradely given via a balloon catheter placed into the1FROZENIX FACTS

previous graft.

perfusion via the femoral artery; subsequently, antegrade

The distal suture line should be remained on the proximal

blood perfusion is resumed via the J Graft, and rewarming issite of the aortic arch. Entries on the distal aortic arch can beinitiated. At this time, sufficient hemostasis of the anastomotic

closed with a patch or direct sutures; however, FROZENIX

line is confirmed.

can cover them without sutures. The adventitia and intima of

The proximal site of the J Graft is anastomosed to the previous

the aortic arch are conjugated to make the anastomosis site.

graft by continuous running suturing with 4-0 monofilament

A felt strip is placed on the outer side of the arch, and foursutures.

pieces of 3-0 monofilament U suture are placed from outside

The trifurcated graft is anastomosed with the one-branched

to inside in a cross direction (Fig. 1a). Then FROZENIX ismain graft in side-by-side fashion to make a bigger

inserted into the true lumen and deployed(Fig. 1b). Whenanastomosis area; it is better placed on the right side of thethe true lumen is narrow or kinked, a guidewire is useful.

main graft to avoid compression by the sternum. Proximal

FROZENIX can be safely inserted with a cable on wire

anastomosis can be performed using a side-bite clamp. Thetechnique 1). A guidewire should be placed in the aortic arch

proximal end of the trifurcated graft is used as an air ventvia the femoral artery before circulatory arrest.

after reperfusion of the heart, and it is lastly closed. TheA balloon catheter is inserted into FROZENIX to confirm

cardiopulmonary bypass is disconnected after completethat it is not kinked. Then the aortic arch is reconstructed

rewarming. The 8-mm ringed graft anastomosed to the left

with a one-branched J Graft. FROZENIX and the J Graft are

axially artery is introduced into the pericardial space via theanastomosed with four pieces of 3-0 U suture that have been

second intercostal space and is anastomosed with the lastplaced in advance and over–over running sutures are appliedbranch of the trifurcated graft. Heparin is neutralized withto conjugate the adventitia, intima, FROZENIX, and J Graftprotamine sulfate after sufficient hemostasis (Fig. 1d).

(Fig. 1c). After the anastomosis, air is removed by blood
Fig. 1 Operative findingsacbda: The adventitia and intima of the aortic arch are conjugated.
b: FROZENIX is inserted into the true lumen and deployed.
c: FROZENIX and J Graft are anastomosed.
d: Reconstruction of the aortic arch with a trifurcated graft.

2

FROZENIX FACTS

the following equation: (maximum diameter + minimum

KNACKS AND TIPSdiameter)/2 or circumferential length of the true lumen/3.

In patients undergoing the ascending aortic replacement

The size of FROZENIX is usually 10% larger than thefor acute type A aortic dissection, adhesions within thediameter of the true lumen. The length of FROZENIX

pericardium are generally severe, and it is important tois generally 9 or 12 cm. It is determined by the distal

remove the adhesions only within the necessary area, namely

anastomosis site and the area where FROZENIX is deployed.

around the right side of the right atrium, the ascending andExtra part of FROZENIX is cut off to remain about 1 cm ofaortic arch. First the innominate vein is dissected and taped.

the non-stented part for anastomosis.

Thereafter, it is generally easy to tape the arch branches.
Adhesions around the replaced artificial graft are always

SURGICAL RESULTS

severe, especially on the distal anastomosis side above thepulmonary artery. Cautions removal is essential to avoid

Eleven cases underwent TAR + FET with FROZENIX frominjury of the pulmonary artery. When adhesions around the2014 to 2016. There were six men (54%) and one case ofright atrium are severe, a left ventricular vent via the rightMarfan syndrome. The initial operation for acute type A aorticsuperior pulmonary vein can be skipped.

dissection was the ascending aorta replacement in nine cases

The range of arch replacement remains within a short lengthand the Bentall procedure in two, and they were done anin many cases. In such cases a trifurcated graft is useful for

average 6.6 ± 4.1 years before the present surgery.

arch branch reconstruction instead of a four-branched graft.

Average operation time, cardiopulmonary bypass time,

The most important point to keep in mind in this procedure iscardiac ischemia time, lower limb ischemia time, and SCP

not to resect the distal part of the aortic arch. In many cases,

time were 618, 296, 138, 72, and 165 minutes, respectively.

the main entries are placed around the proximal arch justThe minimum body temperature was 24.4 ℃ . ICU stay wasabove the previous anastomosis site. The distal anastomosis

8.3 days (2-35), and hospitalization was 37.7 days (14-75).

site should remain within the proximal arch for a secure

There were no hospital deaths and no stroke, but incomplete

procedure because the distal aortic arch is generally enlarged.

paraplegia was complicated in one case, who recovered wellby rehabilitation.
The false lumen was thrombosed in the distal arch to theSIZE SELECTION FOR FROZENIX

upper descending aorta after closure of the proximal entries by

It is mandatory to precisely measure the size of the true

TAR + FET in all cases. The diameter of the false lumen waslumen by CT examination. The diameter is calculated using

decreased, but the diameter of the true lumen was increased;

Fig. 2 Freedom from aortic events

Re-­‐dissection
waiting

Impendingruptureredo

enlargement
redo

Impendingrupture
redoMonths
Rate %
n11100

81.2

70.1

58.4

119633

FROZENIX FACTS

therefore, the diameter of the descending aorta demonstrated

it is important to establish that the insertion length is not

no change. Aortic events were observed after TAR + FET in

too far above the aortic valve position by transesophageal

four cases (36%) during an average follow-up period of 20

echocardiography. On the contrary, in cases where the main

months (Fig. 2). Total descending aorta replacements wereintercostal arteries branch from the false lumen, there is a risk

performed in three of these patients. Aortic events frequentlyof late spinal cord injury accompanying thrombosis of theoccurred after a central repair with TAR + FET; therefore, tofalse lumen. It is also important to keep the blood pressure2)

be cautious, periodical CT follow-up is mandatory . Whenhigh after surgery; a blood pressure higher than 140 mmHg isexpansion of the residual dissection becomes visible, direct

recommended. Spinal cord fluid drainage should be applied

repair of the total descending aorta or thoracoabdominal

without delay when symptoms occur.

aorta via a left thoracotomy should be scheduled (Fig.

REFERENCES3). Furthermore, acute aortic events may happen by stentgraft-induced new entries (SINEs). In such a case, thoracic
endovascular aortic repair is the first concern, but direct repair
has to be rapidly performed due to anatomical limitations insome cases3). Any aortic event should be kept in mind after
TAR + FET.
Spinal cord injury may occur during TAR + FET, even inpatients with aortic dissection4, 5). It is essential to check thelocation and patency of intercostal arteries. In cases where
the main intercostal arteries branch from the true lumen,1) Usui A, Tajima K, Nishikimi N, Ishiguchi T. Implantation of an endovascular
covered stent-graft for distal aortic arch aneurysm via midsternotomy underpigtail catheter guidance. Eur J Cardiothorac Surg. 16:356-358, 1999.
2) Usui A, Ueda Y. Long-term follow-up of the frozen elephant trunk techniquefor distal aortic arch aneurysm. Ann Thorac Surg. 88(1):349, 2009.
3) Jánosi RA, Tsagakis K, Bettin M, Kahlert P, Horacek M, Al-Rashid F, Schlosser
T, Jakob H, Eggebrecht H, Erbel R. Thoracic aortic aneurysm expansion
due to late distal stent graft-induced new entry. Catheter Cardiovasc Interv.
85(2):E43-53, 2015.
4) Watanabe Y, Shimamura K, Yoshida T, Daimon T, Shirakawa Y, Torikai K,Sakamoto T, Shijo T, Toda K, Kuratani T, Sawa Y. Aortic remodeling as aprognostic factor for late aortic events after thoracic endovascular aorticrepair in type B aortic dissection with patent false lumen. J Endovasc
Ther.21(4):517-525, 2014.
5) Usui A, Fujimoto K, Ishiguchi T, Yoshikawa M, Akita T, Ueda Y. Cerebrospinal
dysfunction after endovascular stent-grafting via median-sternotomy (frozenelephant trunk procedure). Ann Thorac Surg. 74:S1821-S1824, 2002.

Fig. 3 Follow-up with multidetector CTabca: Preoperative findings.
b: Postoperative findings.
c: Re-enlargement of the distal arch.
d: Findings after replacement of the total descending aorta.

Higashishinagawa, Shinagawa-ku, Tokyo 140-0002 Japan
http://www.japanlifeline.com
2021-07-00-01d