World Journal of Cardiovascular Surgery, 2013, 3, 101-105
http://dx.doi.org/10.4236/wjcs.2013.33018 Published Online July 2013 (http://www.scirp.org/journal/wjcs)
Root Reconstruction with Total Replacement of
Ascending Aorta Using Hypothermic Circulatory
Arrest and Selective Cerebral Perfusion for
Moderately Dilated Distal Ascending Aorta
Satoshi Yamashiro*, Ryoko Arakaki, Yuya Kise, Hitoshi Inafuku, Yukio Kuniyoshi
Department of Thoracic and Cardiovascular Surgery, University of the Ryukyus, Nishihara, Okinawa, Japan
Received June 3, 2013; revised July 3, 2013; accepted July 10, 2013
Copyright © 2013 Satoshi Yamashiro et al. This is an open access article distributed under the Creative Commons Attribution Li-
cense, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
ABSTRACT
Objective: We have occasionally encountered a moderately dilated distal ascending aorta while reconstructing an aortic
root. We describe reconstruction of an extended root and ascending aorta using our current strategy. Patients and
Methods: Between March 2011 and December 2012, 15 (11 men; mean age, 70.1 ± 7.3 years) patients underwent root
reconstruction with hemi-arch replacement under hypothermic circulatory arrest with antegrade selective cerebral per-
fusion. The maximum diameter of the aortic root was 52.5 ± 4.4 mm. The distal ascending aorta just below innominate
artery was moderately dilated to 41.7 ± 1.4 mm in diameter. Results: Operative outcomes excluding the diameter of the
distal ascending aorta did not significantly differ from those of patients who had undergone root reconstruction under
distal ascending aortic clamping during the same period. Postoperative computed tomography confirmed complete re-
section of the dilated ascending aorta in the patients, and did not develop neurological dysfunction or stroke. Conclu-
sion: Postoperative computed tomography confirmed complete resection of dilated ascending aortae. We considered
that complete resection under hypothermic circulatory arrest and selective cerebral perfusion might help to avoid re-
peated surgery to treat dilation of the distal ascending aorta over the long-term.
Keywords: Annulo-Aortic Ectasia; Re-Operation
1. Introduction
Ascending aorta replacement is the most common strat-
egy for treating thoracic aortic pathologies. Graft repla-
cement for an ascending aortic aneurysm is now a rela-
tively safe and standard surgical procedure. However,
management of a mildly to moderately dilated ascending
aorta during cardiac surgery remains controversial. We
have encountered some patients with a moderately di-
lated distal ascending aorta during aortic root reconstruc-
tion. Distal anastomosis of the ascending aorta usually
proceeds under aortic clamping, when a dilated distal
ascending aorta would remain. The most important con-
sequence of an enlarged ascending aortic dimension is a
proportional increase in the incidence of aortic rupture,
dissection and re-operation. We have routinely wrapped
borderline dilated distal ascending aortae with prosthetic
grafts or felt strips to prevent dilation over the long term.
However, we have recently replaced moderately dilated
ascending aortae (hemi-arch replacement), using open
distal anastomosis for complete resection.
2. Patients and Methods
Between March 2011 and December 2012, 15 patients
(11 men and 4 women; mean age, 70.1 ± 7.3 years) un-
derwent root reconstruction with total replacement of a
dilated ascending aorta under hypothermic circulatory
arrest (HCA) with antegrade selective cerebral perfusion
(ASCP), (HCA group). The ascending aorta was comple-
tely resected just below the innominate artery (hemi-arch
group). All patients were preoperatively diagnosed by
computed tomography (CT), angiography and ultrasound
cardiography as having annulo-aortic ectasia (AAE) with
aortic regurgitation (AR). The maximum aortic root di-
ameter was 52.5 ± 4.4 mm. The distal ascending aorta
just below the innominate artery was moderately dilated
*Corresponding a uthor.
C
opyright © 2013 SciRes. WJCS

S. YAMASHIRO ET AL. 102
to 41.7 ± 1.4 mm in diameter. The root was reconstructed
using the modified Bentall (n = 11) and David (n = 4)
procedures.
The cerebral circulation of all patients undergoing
elective surgery was preoperatively evaluated by Doppler
ultrasonogr aphy of the extracr anial vessels and by digital
subtraction angiography of the extracranial and intracra-
nial circulation. A cardiopulmonary bypass (CPB) was
established with ascending aortic and right axillary arte-
rial cannulation for arterial inflow and right atrial drain-
age. Core cooling was started during CPB to generate
hypothermia over a period of 30 - 40 minutes, during
which, the proximal repair proceeded. The circulation
was arrested when the electroencephalogram flat-lined.
With the patient in the Trendelenberg position, 12 Fr
malleable perfusion cannulae connected to an oxygenator
by a separate single-roller pump head were inserted into
the left common carotid and left subclavian arteries
through the aortic lumen. The cannula in the right axil-
lary artery was used for righ t-sided ASCP with proximal
brachio-cephalic artery clamping using another single-
roller pump. Cerebral perfusion was started at a rate of
10 - 15 mL/min/kg and adjusted to maintain left radial
arterial pressure and bilateral carotid arterial stump pres-
sure between 40 and 60 mmHg. Perioperative blood flow
through the middle cerebral arteries was continuously
monitored using bilateral transcranial Doppler (Viasys
Inc. Conshocken, PA, USA) ultrasonography. Cerebral
oxygen saturation was monitored using an Invos cere-
bral oximeter (Somanetics Co., Troy, MI, USA). Distal
repair proceeded via open distal anastomosis with a sin-
gle-branched Dacron graft. Both HCA and ASCP were
terminated after reconstructing the distal ascending aorta
with antegrade perfusion from the graft branch and then
the proximal repair was completed during rewarming.
Finally, the proximal and distal grafts were anastomosed.
We compared the surgical results with those of pa-
tients whose root reconstruction had proceeded under
distal ascending aortic clamping during the same period
(Clamp group). We also compared postoperative CT
findings with those of patients who had a moderately
dilated distal ascending aorta that had bee n w rapped.
Continuous data are expressed as means ± SD, and
categorical variables are expressed as ratios (%). Char-
acteristics were compared between the two groups using
Student’s t-test.
3. Results
The durations of surgery, total CPB, cardiac ischemia,
ASCP and HCA were 445.6 ± 42.7, 239.9 ± 30.9, 211.3
± 28.2, 33.9 ± 5.9 and 33.0 ± 5.1 minutes, respectively,
in the HCA group. Rectal temperature in these patients
was maintained at 25.4˚C ± 1.6˚C during HCA. Opera-
tive outcomes excluding the diameter of the distal as-
cending aorta (41.5 ± 1.4 vs. 35.4 ± 2.8 mm) and the
lowest rectal temperature during operation (25.4 ± 1.6 vs.
30.6˚C ± 3.7˚C) did not significantly differ from those of
the Clamp group (Table 1).
Neurological dysfunction and postoperative stroke did
not arise in this series. Mechanical ventilation was re-
Table 1. Patient’s characteristics and operative outcomes.
Group HCA group (n = 15) Clamp group (n = 8) P value
Age (years old) 70.1 ± 7.3 65.5 ± 13.9
Gender (M/F) 11/4 7/1
Max Asc Ao. diameter (mm) 52.0 ± 5.7 49.8 ± 10.4
Distal Asc Ao. diamet e r (mm) 41.5 ± 1.4 35.4 ± 2.8 P = 0. 04
Surgical duration (min) 445.6 ± 42.7 505.9 ± 131.6
CPB time (min) 239.9 ± 31.9 253.4 ± 73.6
Cardiac arrest time (min) 211.3 ± 28.7 217.4 ± 67.0
Bleeding (ml) 692.2 ± 298.2 769.0 ± 454.6
Blood Transfusion (ml) 2017.7 ± 698.0 1965.0 ± 1021.0
Rectal temp (˚C) 25.4 ± 1.6 30.6 ± 3.7 P = 0.04
Respiratory time (hours) 12.2 ± 4.2 13.8 ± 5.0
Morbidity 0 1; respiratory failure (12.5%)
Hospitalization (POD; days) 26.2 ± 5.9 35.6 ± 15.1
HCA group: patients underwent root reconstruction with total replacement of the ascending aorta under hypothermic circulatory arrest (HCA) with antegrade
selective cerebral perfusion (ASCP); Clamp group: patients proceeded root reconstruction under distal ascending aortic clamping; Asc Ao.: ascending aorta;
CP: cardiopulmonary bypass; POD: post-operative days. B

S. YAMASHIRO ET AL. 103
quired after surgery for 12.2 ± 4.2 hours. Postoperative
CT confirmed complete resection of the dilated ascend-
ing aorta (Figures 1 and 2). However, the distal ascend-
ing aorta clearly remained dilated after clamping (previ-
ous patients; Figure 3). All patients remained in hospital
for 26.2 ± 5.9 days after surgery. Aetiology of aortic an-
eurysm of this series were not significant different be-
tween both groups (Table 2).
4. Discussion
Although the results of surgical intervention of the tho-
racic aorta have gradually improved, hospital mortality
rates as well as neurological and systemic complications
remain considerable [1]. Therefore, management of the
mildly to moderately dilated ascending aorta has re-
mained controversial. In general, surgery with concomi-
tant cardiovascular procedures especially involving the
Table 2. Aetiology of aneurysms.
HCA group Clamp group
Atherosclerotic change 8 (53.3%) 4 (50.0%)
Degenerative change 6 (40.0%) 3 (37.5%)
Central medial n e c rosis 2 (13.3%) 1 (12.5%)
Aortitis 1 (6.7%) 1 (12.5%)
Bicuspid valve 1 (6.7%) 0
Marfan syndrome 0 1 (12.5%)
Figure 1. Postoperative computed tomography image after
hemi-arch replacement with hypothermic circulatory arrest
and antegrade selective cerebral perfusion. Dilated ascend-
ing aorta is completely resected (arrow).
David
(a) (b)
m-Bentall
(c) (d)
Figure 2. Postoer
hemi-arch ry arrest
perative computed tomography image aft
replacement with hypothermic circulato
and antegrade selective cerebral perfusion. Dilated ascend-
ing aortae are completely resected after David procedure (a,
c) and modified-Bentall operation (b, d) (arrows).
(a) (b)
Figure 3. Posed tomo-
graphy ims dilated
e can proceed when aortic dilation is between
5 - 50 mm in diameter. We had previously wrapped
toperative three-dimensional comput
age. (a, b) Distal ascending aorta remain
after clamping for distal anastomosis of ascending aorta
(arrows).
aortic valv
4
borderline dilated distal ascending aortae with a felt or
prosthetic graft to prevent dilation over the long term.
Some reports have indicated that wrapping effectively
preserves dilated ascending aortae [2-4]. However, we
recently experienced a need to re-operate on a replaced
distal ascending aorta of a male patient that had become
dilated despite being wrapped with a prosthetic graft
(Figure 4). The distal ascending aorta at the initial op-
eration was moderately dilated to a diameter of 43 mm.
Thereafter, we considered that extensive replacement of
the dilated ascending aorta (hemi-arch replacement) us-
ing open distal anastomosis might have been a better

S. YAMASHIRO ET AL. 104
(a) (c)
(b) (d)
Figure 4. Pre- and post-operative computed tomography
images. (a) Aneurysmal dilation of ascending aorta to ma-
ximal diameter of 53 mm in with mildly dilated
distal asceal ascen-
ory management have evolved to in-
rease the safety and duration of cerebral protection.
niques include HCA alone, retrograde cerebral
pe
sion in 1995, and found
th
operative CT
re
a patient
nding aorta; (b) Borderline dilated dist
ding aorta wrapped w ith felt; (c) Distal ascending aorta in-
cludes arch aorta enlarged (arrow) at one year after initial
operation; (d) Reconstructed vessel after repeated aortic
arch replacement.
choice.
Over the past 2 decades, various adjunctive techniques
of cerebral circulat
c
These tech
rfusion (RCP) with HCA, and ASCP with HCA. The
safe time period of HCA to prevent temporary neurologic
dysfunction has been reported to be less than 45 minutes
[5]. The safe duration of HCA is limited and prolonged
periods of HCA are associated with end-organ ischemia
and postoperative neurologic dysfunction [6]. Therefore,
further efforts to improve cerebral protection have led to
the development of antegrade and retrograde cerebral
perfusion. The optimal method of cerebral perfusion (an-
tegrade versus retrograde) is a well-debated topic and has
yet to be determined. RCP can be instituted easily ju st by
clamping the venous drainage tube of the inferior vena
cava, snaring the superior vena cava cannula, and coun-
ter-rotating the CPB pump. However, this method is as-
sociated with two major concerns: insufficient cerebral
oxygen supply and cerebral edema with increased intrac-
ranial pressure due to high venous pressure [7]. ASCP is
employed in many institutions but requires extra arterial
cannulation and, in some cases, an extra arterial pump;
thus, it is relatively complicated and time-consuming [8].
However, only about 20% of adults have anatomically
and functionally completed circle of Wills [9]. Therefor e,
we considered that bilateral ASCP might be unachievable
via unilateral carotid perfusion.
Both HCA with ASCP are currently being applied to
protect the brain. Svenson et al. [10] started applying a
subclavian or axillary artery cannulation strategy with
HCA and antegrade brain perfu
at it was a safe approach to aortic arch surgery because
the stroke risk was < 2%. Technical simplicity and
avoidance of aorta and arch vessel manipulation, as well
as a bloodless operative field, render DHCA an alterna-
tive method of brain protection, especially during as-
cending aorta hemi-arch replacement, when a short pe-
riod of circulatory arrest is anticipated. The advantages
of ASCP are that circulatory arrest can be safely ex-
tended up to 90 minutes, which allows more complex
aortic repair [11]. However, hypothermia-associated co-
agulopathy and pulmonary, renal and micro embolic
complications have been cited in the literature as impor-
tant disadvantages [11]. Rectal temperature in our series
was maintained at 25˚C during HCA and we did not find
an increased risk of coagulative complications. Moderate,
instead of profound hypothermia can reduce the risk of
coagulative and systemic complications. The degree of
hypothermia during this procedure should be considered
when a short period of circulatory arrest is anticipated.
Cerebral oximetry is a functional and possibly superior
method of monitoring cerebral perfusion and oxygena-
tion [12,13]. Although cerebral protection techniques are
continually undergo ing refinement with improved results,
we added left brain perfusion to minimize the likelihood
of associated brain damage arising [14]. Moreover, ver-
tebral perfusion via the left axillary artery is important
for spinal, as well as cerebral protection. Therefore, we
suppose that our method of cerebral protection is accep-
table. The optimal approach to cerebral protection during
these procedures remains controversial.
Indications for total arch replacement in patients with
mildly to moderately dilated ascending and arch aortae
are contentious because the surgical results of extended
arch replacement are suboptimal [15]. Post
vealed complete resection of the dilated ascending
aorta using our procedures. We considered that such
complete resection under HCA and ASCP might prevent
the need for re-operation to treat a dilated distal ascend-
ing aorta over the long term. Neither permanent neuro-
logical dysfunction nor postoperative stroke developed in
this series. Our results suggested that extensive reim-
plantation of the ascending aorta accompanied by ade-
quate HCA and AS CP is effective. Although this study is
limited by the relatively small patient cohort, our find-
ings might have practical implications for the evolution

S. YAMASHIRO ET AL. 105
D. Spielvogel, A. Apaygin, S. L. Lansman, J.
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How?” The Ary, Vol. 67, No. 6
of controversial cases. Aetiology of aortic aneurysm of
this series was not significant different between both
groups. We considered that it is important to the distal
aortic diameter.
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