<div>Title: Aggressive strategy to save the brain in a case of acute aortic
dissection</div><div>Kenji Minatoya, MD, PhD</div><div>Professor and Chairman</div><div>Department of Cardiovascular Surgery,</div><div>Graduate School of Medicine, Kyoto University,</div><div>Kyoto, Japan</div><div>Word count: 927</div><div>Abstract</div><div>The case report by Sicim et al. is the placement of extra-anatomical
bypasses in bilateral common carotid arteries. The similar previous
reports of the extra-anatomical bypass usually indicate unilateral
bypass. Whether or not the Willis’ circle is incomplete is difficult to
judge during emergency surgery, and the authors’ judgment seems to have
been correct in the sense that it could maintain cerebral perfusion
reliably and quickly. The direct perfusion and extraanatomical bypass of
carotid artery is a reasonable strategy in patients with cerebral
malperfusion.</div><div>Cerebral malperfusion as a complication of acute aortic dissection is a
predictor of a poor prognosis. [1][2][3] The malperfusion in
acute aortic dissection is majorly induced by true lumen compression by
a false lumen or intimal flap, but it is not always relieved by
so-called central repair such as ascending aortic replacement.
Therefore, it is always necessary to decide whether to give priority to
the central repair or to release the malperfusion directly depending on
the situation. The central repair may be prioritized if neurological
symptoms such as loss of consciousness after onset are temporary, but if
some neurological symptoms persist, rapid measures for reperfusion of
the brain must be considered.</div><div>This issue of this journal features a case report by Sicim et al.
describing direct bilateral carotid artery cannulations in a case with
extended dissection to the carotid arteries. [4] The patient had
vision loss in both eyes and monoplegia in the left arm. They firstly
commenced direct bilateral carotid artery perfusion, then established
the extracorporeal circulation. Although it took some time, the patient
finally recovered to a state without neurological abnormalities after
rehabilitation. I would like to commend the devoted efforts of the
entire team, including not only this surgical strategy, but also the
fact that this rapid cerebral reperfusion was started in an extremely
short time of less than 30 minutes from the time of the hospital visit.</div><div>As a method for releasing the cerebral malperfusion, it is important to
secure the aortic return of the cardiopulmonary bypass in the true
lumen. Shimura et al. reported that the neurological symptoms of
patients with preoperative cerebral malperfusion were alleviated by
performing the secure true lumen cannulation at the ascending aorta
using the Seldinger technique. [5]</div><div>Femoral artery and axillary artery have been popular cites as the aortic
return among the peripheral arteries. [6] Yet, axillary artery,
subclavian artery, and innominate artery are better to maintain the
antegrade flow and they might improve the cerebral malperfusion since
they are close to the arch branches. [7] The carotid artery is known
to be more accessible than the axillary artery and has less risk of
nerve damage. Urbanski et al. utilized the carotid artery as a site of
aortic return through a short graft anastomosed to the end side instead
of direct cannulation. [8] In addition, multiple cannulations might
be another option to restore true lumen flow and relieve the
malperfusion. [9]</div><div>Selective cerebral perfusion (SCP) in aortic surgery is an established
brain protection method. The standard method is to perfuse
brachiocephalic artery, left common carotid artery, and left subclavian
artery, but it has been reported that it is also possible to perfuse
only the brachiocephalic artery.[10]  The SCP from only one side
functions safely as brain protection in most cases, but considering
safety, perfusion from all branches of the aortic arch is recommended
because there are many cases where the Willis’ ring is incomplete in the
skull. [11] Moreover, as in this case, when the branches of the arch
are dissected, the brain protection is incomplete by the standard method
of selective cerebral perfusion from only the orifice of the arch
branches. In such cases, it makes sense to secure a blood supply channel
directly to the periphery of the arch branch.</div><div>Several cases regarding this extra-anatomical bypass to neck arteries
have been reported. Gomibuchi et al. reported that postoperative
neurological complications were reduced by additional cannulation at the
common carotid artery in patients with preoperative imaging cerebral
malperfusion. [12] Sugiyama et al. performed direct cannulation to
the common carotid artery in addition to the usual selective cerebral
perfusion to all branches of the aortic arch for cases in which
dissection had extended to the common carotid artery on preoperative CT
imaging in their later series. They described the neurological
complications have been drastically reduced with this aggressive
method. [13] The mechanism of the cerebral malperfusion is not
always same, however, when a major entry is in the ascending aorta,
malperfusion mostly occurs on the right due to the location of the entry
and a unique configuration of vessel bifurcation. The right common
carotid artery is obstructed by either the intimal flap in the
innominate artery or by an expanded false lumen. [14] What is
interesting in this case report by Sicim et al. is the placement of
extra-anatomical bypasses in bilateral common carotid arteries. Whether
or not the Willis’ circle is incomplete is difficult to judge during
emergency surgery, and the authors’ judgment seems to have been correct
in the sense that it could maintain cerebral perfusion reliably and
quickly.</div><div>Okita et al. have introduced a method for maintaining cerebral perfusion
using a shunt from the femoral artery to the right common carotid artery
preoperatively. [15] They described their criteria of the direct
cannulation of the carotid artery. They are at least one sign or symptom
of diminished flow in the carotid arteries, such as dissected carotid
arteries with compressed true lumen by CT scan, decreased blood flow in
the carotid artery demonstrated by ultrasound, persistent consciousness
disorder, hemiparesis, or tight to left difference in forehead rSO2 or
arm blood pressures. However, it has also been pointed out that it is
necessary to control the perfusion rate for cerebral ischemia to prevent
reperfusion injury. [16]</div><div>To further improve the surgical results of acute aortic dissection, it
is important to establish a strategy for cerebral malperfusion. Once
again, I would like to congratulate the authors saving the patient
without severe neurological symptoms by adopting the aggressive
strategy, and clarify that this case report will be useful information
for our readers.</div><div>[1] Pansini S, Gagliardotto PV, Pompei E, Parisi F, Bardi G,
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