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\begin{document}

\title{Early superior mesenteric artery revascularization for acute type A
aortic dissection with cardiac tamponade and mesenteric malperfusion}



\author[1]{Sho Kusadokoro}%
\author[1]{Naoyuki Kimura}%
\author[1]{Kosuke Miyoshi}%
\author[1]{Daijiro Hori}%
\author[1]{Manabu Shiraishi}%
\author[1]{Atsushi Yamaguchi}%
\affil[1]{Saitama Medical Center, Jichi Medical University}%


\vspace{-1em}



  
  \date{May 25, 2024}


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\selectlanguage{english}
\begin{abstract}
We report herein successful treatment of a case of acute type A aortic
dissection complicated by cardiac tamponade and mesenteric malperfusion.
The patient was a 60-year-old man, with back and abdominal pain and in
shock, who was transported to our hospital 2 hours after symptom onset.
Computed tomography revealed DeBakey type I dissection with massive
hemopericardium and obstruction of both the celiac artery and superior
mesenteric artery. After emergency pericardiotomy and removal of the
hematoma, superior mesenteric artery-external iliac artery bypass was
constructed with a vein graft, and this restored mesenteric perfusion.
Open distal hemiarch replacement was then performed. The postoperative
course was uneventful. Superior mesenteric artery revascularization
achieved immediately after release of the cardiac tamponade prevented
further mesenteric ischemia and paved the way for the aortic repair.%
\end{abstract}%



\sloppy


\textbf{Keywords}

acute type A aortic dissection, cardiac tamponade, mesenteric
malperfusion



\textbf{1 INTRODUCTION}

Acute type A aortic dissection (ATAAD) remains a life-threatening
emergency. Cardiac tamponade\textsuperscript{1} and mesenteric
malperfusion\textsuperscript{2} are known to increase the operative risk
in patients with ATAAD. Central aortic repair involving resection of the
primary entry tear can improve the perfusion status by increasing blood
flow in the true lumen. However, timely reperfusion is mandatory for
organ protection, and the beneficial effects of central aortic repair
are limited in patients with dissection extending to the peripheral
aortic branch. Although the utility of endovascular stenting to clear
arterial blockage has been reported,\textsuperscript{3} concomitant
cardiac tamponade may further complicate the therapeutic process. We
report herein successful treatment of a patient with ATAAD presenting
with shock caused by cardiac tamponade and mesenteric malperfusion.

\textbf{1.1 Patient profile}

The patient was a 60-year-old man with hypertension and diabetes who was
transported by ambulance to our hospital's emergency 2 hours after onset
of sudden back and abdominal pain. On admission, the patient's blood
pressure was 90/66 mmHg, and palpation revealed abdominal tenderness.
Cardiac ultrasonography revealed preserved left ventricular wall motion,
mild aortic insufficiency, and massive pericardial effusion.
Contrast-enhanced computed tomography (CT) revealed a primary entry tear
in the ascending aorta, pericardial effusion, a patent false lumen and
narrowed true lumen in the descending aorta, obstruction of the proximal
celiac artery and superior mesenteric artery (SMA), and dissection
extending into the right external iliac artery (Figure 1). Arterial
blood gas analysis revealed metabolic acidosis (pH 7.22), and the blood
lactate level was increased to 7.46 mmol/L. ATAAD (DeBakey type I) with
cardiac tamponade and mesenteric malperfusion was diagnosed

\textbf{1.2 Surgical procedure}

The patient was transferred immediately to the operating room. During
induction of anesthesia, the patient's blood pressure dropped to 55/35
mmHg. Median sternotomy and pericardiostomy were performed immediately.
A massive hematoma was removed, improving the patient's hemodynamic
status. Careful inspection revealed no active bleeding from the aorta.
Exploratory laparotomy showed extensive bowel ischemia, recognized by
intestinal pallor, absence of peristaltic movement, and loss of
pulsation of the main trunk and branches of the SMA. To prevent
progression to irreversible bowel damage, SMA-left external iliac artery
bypass was performed by application of a saphenous vein graft. After
revascularization of the SMA, mesenteric perfusion quickly improved, as
evidenced by pulsation of the intestinal arteries and peristalsis.
Cardiopulmonary bypass (CPB) was then established by cannulation of the
right femoral artery and the superior and inferior vena cava and
placement of a left ventricular venting tube via the right upper
pulmonary vein. The patient was cooled to 21.9\selectlanguage{ngerman}°C, and the dissected
ascending aorta was excised. The primary entry tear was resected, and
open distal hemiarch replacement was performed. There were no further
signs of mesenteric malperfusion during the surgery. The abdomen was
closed on postoperative day (POD) 1, and the patient was extubated on
POD 2. The postoperative course was uneventful, and CT performed on POD
7 showed an expanded true lumen, opened side branches of the abdominal
aorta, and patency of the venous graft. The patient was discharged
complication free on POD 20. CT performed 8 months after the surgery
revealed a patent venous graft (Figure 2). Twelve months have passed
since the surgery, and the patient remains healthy.

\textbf{2 DISCUSSION}

Outcomes of aortic repair for ATAAD have improved. According to a
Japanese Association for Thoracic Surgery annual report, overall
in-hospital mortality of patients who underwent aortic repair for ATAAD
in 2015 was 9.6\% (468/4875).\textsuperscript{4} Organ malperfusion
associated with ATAAD remains a surgical challenge; patient-specific
approaches are required. Shiiya et al. reported that sole central aortic
repair failed to revascularize the abdominal organ(s) in 5 of 6 patients
with aortic branch dissection.\textsuperscript{5} Uchida et al. reported
favorable outcomes of a surgical strategy that prioritizes peripheral
revascularization in patients with organ
malperfusion.\textsuperscript{6} If a patient shows stable hemodynamics
and branch-type malperfusion, early revascularization seems to be a
feasible approach. Our patient's ATAAD was complicated by severe
mesenteric malperfusion resulting from occlusion of both the celiac
artery and SMA. We think that sole central aortic repair or delayed SMA
revascularization could have resulted in irreversible mesenteric
ischemia.

Previously, we reported ATAAD complicated by malperfusion of at least
one organ in 30.9\% (308/1029) of patients and that we found obesity
(body mass index \textgreater{}30 kg/m\textsuperscript{2}), preoperative
shock (systolic blood pressure \textless{}80 mmHg), and mesenteric
malperfusion to be independent predictors of-in-hospital death for those
with such malperfusion.\textsuperscript{7} Treatment of the
ATAAD-induced cardiac tamponade is of paramount importance in patients
undergoing immediate aortic repair; however, the optimal management
technique remains controversial. Lin et al. reported similar outcomes
between emergency subxiphoid pericardiotomy and emergency establishment
of CPB.\textsuperscript{8} Pericardiotomy performed initially for
hematoma removal poses a risk of continuous bleeding in cases of aortic
rupture. Our case was complicated by cardiac tamponade leading to
hemodynamic instability, but aortic rupture had not occurred. In cases
of aortic rupture, CPB must be established promptly, before the aortic
repair. Revascularization of abdominal organs would be the second
priority in such cases.

In conclusion, in our case of ATAAD complicated by cardiac tamponade and
severe mesenteric malperfusion, initial release of pericardial hematoma
and revascularization of the SMA prevented further mesenteric ischemia
and paved the way for aortic repair.

\textbf{Author contributions}

SK wrote the original draft of this report, and NK revised it. KM, DH,
MS and AY were involved in the patient's care. All authors have reviewed
and approved the submission of the manuscript.



\textbf{REFERENCES}

1. Gilon D, Mehta RH, Oh JK, et al. Characteristics and in-hospital
outcomes of patients with cardiac tamponade complicating type A acute
aortic dissection. Am J Cardiol. 2009;103:1029-1031.

2. Di Eusanio M, Trimarchi S, Patel HJ, et al. Clinical presentation,
management, and short-term outcome of patients with type A acute
dissection complicated by mesenteric malperfusion: observations from the
International Registry of Acute Aortic Dissection. J Thorac Cardiovasc
Surg. 2013;145:385-390 e1.

3. Obied HY, Ghoneim A, Ibrahim MF. Hybrid approach to repair type A
aortic dissection: combined endovascular superior mesenteric artery
stenting and Bentall procedure. Aorta. 2014;2:156-160.

4. Association for Thoracic Surgery. Committee for Scientific Affairs,
The Japanese Association for Thoracic Surgery; Masuda M, Endo S,
Natsugoe S, et al. Thoracic and cardiovascular surgery in Japan during
2015: annual report by The Japanese Association for Thoracic Surgery.
Gen Thorac Cardiovasc Surg. 2018:66, 581-615.

5. Shiiya N, Matsuzaki K, Kunihara T, Murashita T, Matsui Y. Management
of vital organ malperfusion in acute aortic dissection: proposal of a
mechanism-specific approach. Gen Thorac Cardiovasc Surg. 2007;55:85-90.

6. Uchida K, Karube N, Kasama K, et al. Early reperfusion strategy
improves the outcomes of surgery for type A acute aortic dissection with
malperfusion. J Thorac Cardiovasc Surg. 2018;156:483-489.

7. Kawahito K, Kimura N, Yamaguchi A, Aizawa K. Malperfusion in type A
aortic dissection: results of emergency central aortic repair. Gen
Thorac Cardiovasc Surg. 2019;67:594-601.

8. Lin CY, Wu MY, Tseng CN, et al. Surgical rescues for critical
hemopericardium complicated by acute type A aortic dissection: emergent
subxiphoid pericardiotomy or cardiopulmonary bypass first? PloS One.
2020;15:e0229648.

\textbf{Figure Legends}

\textbf{FIGURE 1}

CT images obtained preoperatively depict (A) an entry tear in the
ascending aorta, a patent false lumen with a narrowed rue lumen in the
descending aorta, and massive pericardial effusion; (B,C) obstruction of
the proximal abdominal aortic branches, i.e., celiac artery and SMA; (D)
dissection extending into the right external iliac artery but an intact
left external iliac artery; and (E) obstruction of the proximal celiac
artery and SMA (3D CT image). CT, computed tomography; SMA, superior
mesenteric artery.

\textbf{FIGURE 2}

3D CT image obtained 8 months after the surgery showing the vein graft
from the left external iliac artery to the SMA to be patent, with blood
flowing freely through the celiac artery and SMA. CT, computed
tomography; SMA, superior mesenteric artery.\selectlanguage{english}
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