FROZENIX FACTS

Safe and Less Invasive Surgery
for Acute Type A Aortic Dissection:“Zone 0 arch repair” Strategy
Vice Director of Akita University Hospital
Professor and Chair of Cardiovascular Surgery, Akita University Graduate School of Medicine

Hiroshi Yamamoto, MD, PhD

remaining patent false lumen after HAR for DeBakey type I

INTRODUCTION

may be involved in postoperative events in the downstream

Surgical treatment strategy in acute type A aortic dissection,aorta. If the primary tear is resected, blood flow into theparticularly in patients with DeBakey type I or type III

false lumen (FL) may continue and cause an expansion of(Retrograde), has been controversial in terms of superiority

the FL due to residual tears in the aortic arch and proximal

and inferiority in postoperative early and late outcomes.

descending aorta or newly developed tears in the suture line ofCurrently, aortic resection based on a “tear-oriented” strategy

the distal anastomosis.4) Therefore, when considering a moreis recommended in acute Type A aortic dissection. Hemiarch

ideal surgical strategy, it is important that (1) the aortic archor ascending aortic replacement (HAR) is used for patients

resection is avoided, (2) the FL thrombosis in the distal archwith a primary tear in the ascending aorta or along the innerand descending aorta is facilitated, and (3) reintervention tocurvature of the aortic arch. Total arch replacement (TAR)

the downstream aorta can be performed with an endovascularwith or without an elephant trunk is selected when the primaryapproach.

tear is located in the aortic arch or descending aorta. Recent

In 2014, a prospective randomized study in patients with acutereports have shown that postoperative early mortalities ortype B aortic dissection showed that stent graft implantation1)

into the true lumen (TL) to close the entry tear significantly

However, TARs are more invasive and have a higher risk of

reduced the FL diameter.5) This suggests that even if multiple

postoperative organ injury or respiratory disorder compared totears exist, FL thrombosis and elimination (i.e., aorticHARs.2) On the other hand, the late distal reintervention rates

remodeling) can be achieved (due to the entry closure) usingafter HARs have been reported to be significantly higher thanendovascular techniques. The study rationalized the efficacy

those of TARs. A report from the University of Pennsylvaniaof aortic remodeling by deploying a stent graft from zone 0

comparing the postoperative outcomes of HAR between 177

to the descending aorta. Based on this, in 2014, we developedpatients with DeBakey type I and 357 patients with DeBakey

a surgical strategy called “Zone 0 arch repair” using a frozen

type II showed that the distal reintervention rate after HAR

elephant trunk (FET) technique as an alternative to the “tear-in patients with DeBakey type I was significantly higher thanoriented” strategy. The FET technique was developed by Katopatients with DeBakey type II, and that 28 of 32 postoperativeet al.6) in Japan and is now being performed globally. Since

reinterventions underwent open repair.3) This suggests that theOctober 2014, we have used the “Zone 0 arch repair” strategy,

complications are comparable between TARs and HARs.

1

FROZENIX FACTS

consisting of (1) FET deployment from zone 0 aorta to the3). The distal aorta was trimmed 2 cm proximal to thedescending aorta, (2) ascending aortic replacement, and (3)origin of the brachiocephalic artery. The FROZENIX7)

prosthesis was inserted from the distal aortic end (zone 0)

arch vessel reconstructions.

into the descending aorta, and the distal end of the stentwas positioned at the level just above the aortic valve using

SURGICAL PROCEDURES

transesophageal echocardiographic guide. The stent part

Under general anesthesia, an anastomosis was performed

length has been principally set at 150mm since December(using a vascular graft) to the left axillary artery for2019. In our practice, to determine device length, we take thesystemic perfusion. A median sternotomy was carried out

proximal end of the implant and position it at the origin of theand hypothermic total cardiopulmonary bypass (CPB)

brachiocephalic artery branch. Then for the device diameter,

was initiated by venous cannulation via the superior andwe take 90-100% of the descending aortic diameter at theinferior vena cava. After the ascending aorta was clamped,

level of the main pulmonary arteries according to preoperativecardiac arrest was induced with a cold blood cardioplegicenhanced CT scans. The proximal graft portion of thesolution injected in an antegrade and retrograde manner. TheFROZENIX was trimmed and anastomosed together with theascending aorta was transected, and the proximal aorta wasdistal aortic wall to a 4-branched arch graft (J Graft vasculartrimmed 1 cm distal to the sinotubular junction. Subsequently,prosthesis) using a continuous stitch of 4-0 monofilament

the thrombus in the FL was carefully removed, and then thesuture reinforced with pericardial strips. Distal perfusion wasdissecting aortic walls were reapproximated by applying

resumed from the perfusion side branch of the 4-branched

BioGlue® and clamping with Bolst pliers. This was followed

graft. During systemic rewarming, proximal anastomosis wasby fixation of the proximal aorta using a continuous stitch of

performed with 4-0 polypropylene suture (Fig. 4).

5-0 polypropylene sutures reinforced with bovine pericardial

The first branch of the arch prosthesis is used for de-airing

strips (approximately 8 mm in width) inside and outside of theduring myocardial reperfusion (Fig. 5). The third and second

aortic wall (Fig 1, 2).

branches of the arch prosthesis were anastomosed to the left

Circulatory arrest (CA) was initiated when the rectal

common carotid and brachiocephalic arteries, respectively,

temperature was below 25 ˚ C. The left subclavian arterywith 5-0 sutures reinforced with pericardial strips. Finally, thewas ligated at the origin and left axillary arterial perfusion

perfusion side branch was anastomosed to the prosthesis for

was resumed. Selective cerebral perfusion (SCP) was thenaxillary artery perfusion drawn to the anterior mediastinum

performed to the left carotid and brachiocephalic arteries,

via the left thoracic cavity prior to protamine infusion after

and the proximal ends of both arteries were closed (Fig.

CPB was stopped (Fig. 6).

Fig. 1

Fig. 2

Bovine pericardium

2

FROZENIX FACTS

clamping the vascular prosthesis between the first and second

CONCLUSIONS

branches of the arch graft, which allows a sufficient working

This strategy, consisting of (1) FROZENIX deployment

space during the repair procedure. In our experience of 108

from the ascending (zone 0) aorta into the descendingpatients (Oct 2014 – April 2018) that underwent surgery based

aorta, (2) ascending aortic replacement, and (3) arch vesselon the “zone 0 arch repair” strategy for type A acute aortic

reconstructions, is straightforward, safe, and less invasive,

dissection, the 30-day mortality rate was 2.8% (3/108) and thewhich may lead to reasonable early postoperative results. An

hospital mortality rate was 6.5% (7/108). The postoperativeadvantage for late postoperative results is that aortic events

CT 3 weeks after surgery revealed complete FL thrombosis of(late TL stenosis or FL dilation) in the downstream aorta

the aortic arch level for all cases. The cumulative incidence of

can be fixed by endovascular techniques without open aortic

aortic reintervention was 5.8%, 9.1%, and 9.1% at 1, 2, and 3

repairs. Furthermore, if any problem occurs in the proximalyears, respectively.7)

anastomotic site, cardioplegic arrest can be induced byBrachiocephalic a.

Fig. 3Fig. 4

Left carotid a.
Left axillary a.

SCP

CPB

CPB

Fig. 5

Fig. 6

Root venting
CPBCPB3FROZENIX FACTS

REFERENCES
1) Poon SS, Theologou T, Harrington D, Kuduvalli M, Oo A, Field M. Hemiarch versus total aortic arch replacement in acute type A dissection: a systematic review and metaanalysis. Ann Cardiothorac Surg 2016; 5: 156-73.
2) Rylski B, Milewski RK, Bavaria JE, Vallabhajosyula P, Moser W, Szeto WY, Desai ND. Long-term results of aggressive hemiarch replacement in 534 patients with type A aortic
dissection. J Thorac Cardiovasc Surg 2014; 148: 2981-5.
3) Kim JB, Chung CH, Moon DH, Ha GJ, Lee TY, Jung SH, Choo SJ, Lee JW. Total arch repair versus hemiarch repair in the management of acute DeBakey type I aorticdissection. Eur J Cardio-thoracic Surg 2011; 40: 881-9.
4) Zhang H, Lang X, Lu F, Song Z, Wang J, Han L, Xu Z. Acute type A dissection without intimal tear in arch: Proximal or extensive repair? J Thorac Cardiovasc Surg 2014; 147:
1251-5.
5) Brunkwall J, Kasprzak P, Verhoeven E, Heijmen R, Taylor P, the ADSORB Trialists. Endovascular repair of acute uncomplicated aortic type B dissection promotes aortic
remodeling: 1 year results of the ADSORB Trial. Eur J Vasc Endovasc Surg 2014; 48: 285-91.
6) Kato M, Onishi K, Kaneko M, Ueda T, Kishi D, Mizushima T, Matsuda H. New graft-implanting method for thoracic aortic aneurysm or dissection with a stented graft.
Circulation 1996; 94(Suppl II): II188-93.
7) Yamamoto H, Kadohama T, Yamaura G, Tanaka F, Takagi D, Kiryu K, Itagaki Y. Total arch repair with frozen elephant trunk using the “zone 0 arch repair” strategy for type A
acute aortic dissection. J Thorac Cardiovasc Surg 2020; 159: 36-45 (DOI: http://doi.org/10.1016/j.jtcvs.2019.01.125).

PROFILE

Hiroshi Yamamoto, MD, PhD
Vice Director of Akita University Hospital
Professor and Chair of Cardiovascular Surgery, Akita University Graduate School of Medicine
1983
1985
1986
1989
1994
1998
2001
2014-present
2019-present

Asahikawa Medical College, General Surgical Residency
Asahikawa Medical College, Anesthesiology Residency
National Cardiovascular Center, Cardiovascular Surgical Residency
Cardiovascular Research, The Rayne Institute, St Thomas’ Hospital, London, UKAssistant Professor of First Department of Surgery, Asahikawa Medical College
Lecturer of First Department of Surgery, Asahikawa Medical College
Associate Professor of Cardiovascular Surgery, Akita University Graduate School of Medicine
Professor and Chair of Cardiovascular Surgery, Akita University Graduate School of Medicine
Vice Director of Akita University Hospital

Higashishinagawa, Shinagawa-ku, Tokyo 140-0002 Japan
http://www.japanlifeline.com

2021-07-00-01