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\begin{document}

\title{Endovascular rescue for malpositioned frozen elephant trunk into the
false lumen}



\author[1]{Daichi Takagi}%
\author[2]{Takuya Wada}%
\author[2]{Wataru Igarashi}%
\author[1]{Takayuki Kadohama}%
\author[2]{kentaro kiryu}%
\author[1]{Takeshi Arai}%
\author[2]{Hiroshi Yamamoto}%
\affil[1]{Akita University}%
\affil[2]{Akita University Graduate School of Medicine School of Medicine}%


\vspace{-1em}



  
  \date{May 21, 2024}


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\selectlanguage{english}
\begin{abstract}
We describe a case of frozen elephant trunk deployment unintentionally
malpositioned into the false lumen. An 83-year-old man underwent total
arch repair with a frozen elephant trunk for type A acute aortic
dissection complicated by mesenteric malperfusion. However,
intraoperative transesophageal echocardiography showed expansion of the
false lumen in the descending aorta, suggesting a malpositioned frozen
elephant trunk into the false lumen. Endovascular fenestration of the
dissecting flap and subsequent endograft deployment from the inside of
the malpositioned frozen elephant trunk graft to the true lumen of the
descending aorta was successfully performed under intravascular
ultrasound guidance.%
\end{abstract}%



\sloppy


\textbf{Endovascular rescue for malpositioned frozen elephant trunk into
the false lumen}

Daichi Takagi, MD, PhD, Takuya Wada, MD, Wataru Igarashi, MD, Takayuki
Kadohama, MD, PhD, Kentaro Kiryu, MD, Takeshi Arai, MD, Hiroshi
Yamamoto, MD, PhD

Department of Cardiovascular Surgery, Akita University Graduate School
of Medicine, Hondo 1-1-1, Akita, 010-8543, Japan

Running head: Malpositioned FET graft

\textbf{Correspondence}

Daichi Takagi, MD, PhD, Department of Cardiovascular surgery, Akita
University Graduate School of Medicine, Hondo 1-1-1, Akita, 010-8543,
Japan.

Tel: +81-18-884-6135

Fax: +81-18-836-2625

E-mail: daichi0129@gmail.com

\textbf{Prior Presentation:} None.

\textbf{Funding:} None.

\textbf{Conflict of Interests:} None.

\textbf{Abstract}

We describe a case of frozen elephant trunk deployment unintentionally
malpositioned into the false lumen. An 83-year-old man underwent total
arch repair with a frozen elephant trunk for type A acute aortic
dissection complicated by mesenteric malperfusion. However,
intraoperative transesophageal echocardiography showed expansion of the
false lumen in the descending aorta, suggesting a malpositioned frozen
elephant trunk into the false lumen. Endovascular fenestration of the
dissecting flap and subsequent endograft deployment from the inside of
the malpositioned frozen elephant trunk graft to the true lumen of the
descending aorta was successfully performed under intravascular
ultrasound guidance.



\textbf{Introduction}

Frozen elephant trunk (FET) deployment for type A acute aortic
dissection (TAAD) has been widely accepted because it induces aortic
remodeling in the downstream aorta.\textsuperscript{1} FET malposition
into the false lumen (FL) has rarely been reported. However, urgent
intervention is required to prevent ischemic organ damage because
endograft malposition has dire consequences for visceral, renal, and
lower extremity perfusion.\textsuperscript{2,3} In this report, we
describe the clinical features of this complication and the endovascular
technique used to divert back persistent FL perfusion to the true lumen
(TL) of the downstream aorta. The patient provided consent for this
report.

\textbf{Case Report}

An 83-year-old man presented with acute-onset abdominal pain. Computed
tomography (CT) revealed TAAD with primary entry tear at the distal
aortic arch and compression of the TL by the FL in the superior
mesenteric artery (SMA) with dilated and fluid-filled small bowel loops
(Figure 1). Thus, the diagnosis was TAAD, complicated by mesenteric
malperfusion. We decided to reperfuse the visceral organs before central
aortic repair.

An emergency surgery was performed under general anesthesia. Laparotomy
was performed, and a pulseless SMA and small bowel ischemia were
identified. Under fluoroscopic guidance, a 10-mm stent (SMART; Cordis
Corp., Miami Lakes, FL, USA) was deployed at the ostium of the SMA in a
retrograde fashion through the 6 Fr sheath inserted from the branch of
the SMA, which was then connected to the femoral artery sheath, which
served as an external shunt. Thereafter, total arch repair with FET,
``Zone 0 arch repair strategy,\textsuperscript{1}'' was performed using
a FET graft and a 4-branched graft (35 mm \selectlanguage{ngerman}× 150 mm J Graft FROZENIX and
28 mm J Graft SHIELD, respectively; Japan Lifeline Co. Ltd., Tokyo,
Japan). A primary entry tear was identified in the distal aortic arch
(Figure 2A). The FET graft was carefully inserted into the descending
aorta under direct vision. After weaning from cardiopulmonary bypass
(CPB), the SMA remained pulseless. In addition, transesophageal
echocardiography (TEE) showed expansion of the FL in the descending
aorta distal to the FET graft, suggesting malposition of the FET into
the FL of the descending aorta (Figure 2B). Thereafter, malposition of
the FET was confirmed using intravascular ultrasound (IVUS).

Percutaneous fenestration of the dissecting flap and endograft
deployment from the inside of the malpositioned FET to the TL of the
descending aorta were subsequently performed. Under IVUS and
fluoroscopic guidance, an angled 5-Fr catheter (Impress Diagnostic
Peripheral catheter; Merit Medical, South Jourdan, UT, USA) was rotated
and its tip was positioned against the center of the dissecting flap.
Then the dissecting flap, 4 cm distal to the distal end of the FET, was
perforated using a 0.014-inch tapered tip microguidewire (Chevalier14
Tapered 30; FMD Co., Ltd, Tokyo, Japan) by a quick, short thrust. The
outer catheter was advanced over the microguidewire from the TL to the
FL of the descending aorta. Thereafter, a 0.035-inch extra-stiff
guidewire (Lunderquist; Cook Medical Inc., Bloomington, IN, USA) was
reintroduced through the outer catheter, and a stiff guidewire was
placed across the dissecting flap to the inside of the FET (Figure
2D/E/F). A tapered 38/34 mm × 190 mm endograft (Relay Plus; Bolton
Medical, Sunrise, FL, USA) was deployed from the inside of the FET to
the TL of the descending aorta. Subsequent aortography showed no
endoleak, and IVUS revealed good expansion of the endograft and the TL
of the downstream aorta. SMA pulsation and bowel peristalsis returned
after endograft deployment. Postoperative complications related to
aortic or visceral malperfusion were not observed. Follow-up CT revealed
a patent endograft and expansion of the TL of the downstream aorta
without SMA stenosis (Figure 3).

\textbf{Discussion}

Although extremely rare, FET malposition into the FL is reported to be a
fatal complication. Most cases of FET malposition into the FL were
diagnosed using postoperative CT.\textsuperscript{2-4} Tamai et al.
reported a case of FET malposition diagnosed by TEE during circulatory
arrest that was successfully treated by additional FET deployment into
the TL.\textsuperscript{5} In our case, FET malposition was suspected
after weaning from CPB by TEE and pulseless SMA. Although FET removal
and re-deployment or additional FET deployment into the TL could be
alternative options, we performed endovascular rescue because additional
cardiac and circulatory arrest could cause excessive invasion.

Fenestration of the dissecting flap using a radio frequency system and
subsequent endograft deployment has been reported as an effective
technique in cases of chronic dissection.\textsuperscript{4} However,
percutaneous endovascular fenestration and endografting for FET
malposition in cases of acute dissection have never been reported.
Because the dissecting flap architecture is much thinner in acute
dissection than in chronic dissection,\textsuperscript{6} the dissecting
flap can be easily perforated only by a tapered tip microguidewire
through an angled catheter under IVUS and fluoroscopic guidance.

In conclusion, percutaneous endovascular fenestration of the dissecting
flap and subsequent endograft deployment from the FET to the TL of the
descending aorta under the guidance of IVUS are effective and
less-invasive surgical treatments after FET malposition into the FL for
TAAD.

\textbf{Author contributions}

Daichi Takagi wrote the manuscript; other authors surpervised the case.

The authors have obtained the patients' informed consent for
publication. Institutional Review Board review is not applicable to this
report.

\textbf{References}

1. Yamamoto H, Kadohama T, Yamaura G, et al. Total arch repair with
frozen elephant trunk using the ``zone 0 arch repair'' strategy for type
A acute aortic dissection. \emph{J Thorac Cardiovasc Surg} .
2019;159:36-45. DOI:\emph{10.1016/j.jtcvs.2019.01.125}.

2. Han SM, Gasper WJ, Chuter TAM. Endovascular rescue after inadvertent
false lumen stent graft implantation. \emph{J Vasc Surg} .
2016;63:518-522. DOI:\emph{10.1016/j.jvs.2014.11.072}.

3. Fujii M, Watanabe H, Otsu M, Sugahara Y. Incorrect frozen elephant
trunk deployment into the false lumen of a patient with complicated type
B acute dissection. \emph{Eur J Cardiothorac Surg} . 2019;55:1222-1224.
DOI:\emph{10.1093/ejcts/ezy357}.

4. Wong RHL, Yu PSY, Kwok MWT, et al. Endovascular fenestration for
distal aortic sealing after frozen elephant trunk with
thoraflex.\emph{Ann Thorac Surg} . 2017;103:e479-e482.
DOI:\emph{10.1016/j.athoracsur.2016.12.039}.

5. Tamai K, Hori D, Yuri K, Yamaguchi A. Additional frozen elephant
trunk as a bailout for a misdeployed frozen elephant trunk in the false
lumen in a patient with acute aortic dissection. \emph{Eur J
Cardiothorac Surg.} 2020;57:399-401. DOI:\emph{10.1093/ejcts/ezz213}.

6. Peterss S, Mansour AM, Ross JA, et al. Changing pathology of the
thoracic aorta from acute to chronic dissection: Literature review and
insights. \emph{J Am Coll Cardiol} . 2016;68:1054-1065.
DOI:\emph{10.1016/j.jacc.2016.05.091}.

\textbf{Figure Legends}

Figure 1. Preoperative computed tomography (CT) revealed type A acute
aortic dissection. (A) Three-dimensional CT. (B) Primary entry tear
located in the distal aortic arch. (C/D) True lumen of the ascending
aorta, abdominal aorta, and superior mesenteric artery were severely
compressed by the false lumen. Dilated and fluid-filled small bowel
loops suggested mesenteric malperfusion.

Figure 2. (A) Primary entry tear was identified at the distal aortic
arch under direct vision. (B) Intraoperative transesophageal
echocardiography revealed true lumen (TL) stenosis and false lumen (FL)
expansion in the downstream aorta. (C) Aortography. White and red arrows
showed the levels of panels D, E, and F. (D, E, F) Intravascular
ultrasound revealed FL expansion and TL stenosis at all levels. The
stiff guidewire was introduced in the FL at the level just distal to the
misdeployed frozen elephant trunk (D) across the dissecting flap at the
perforation point (E; red arrow) and in the TL of the descending aorta
(F). TL, true lumen; FL, false lumen

Figure 3. Postoperative computed tomography (CT). (A) An endograft was
deployed from the inside of the FET to the TL of the descending aorta
across the perforated dissecting flap (white arrow). (B, C, D) The FET,
additional endograft, the true lumen of the SMA, and the abdominal aorta
were patent without any stenosis\selectlanguage{english}
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