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Nardi P, Ruvolo G.
to Surgical Repair of the Aneurysms of Ascending
. Journal of Vascular & Endo Surgery.
April 28, 2016;
April 29, 2016;
May 03, 2016
Normal ascending aorta functions as an elastic reservoir to
enhance arterial flow. It stores energy during systole and
dissipates it during diastole. The medial layer of the aorta
consisting of elastin, collagen, and smooth muscle cells ensures
the elasticity of the aortic wall. The ascending segment of the
aorta is more elastic than the descending segment, due to its
greater concentration of elastic fibres. Aortic aneurysm is defined
as a permanent dilation of the aortic wall that exceeds 1.5 times
the normal diameter of the aorta in a specified its segment (i.e.,
the segment of the ascending aorta has a normal value of 24-36
mm, and its dilation for a diameter >40 mm is called aneurysm).
Ascending aortic aneurysms are exposed to the risk of rupture
with sudden death from cardiac tamponade, or dissection, i.e.,
acute, a dramatic event that can lead to cardiac tamponade,
acute aortic valve insufficiency and severe ischemia of the heart,
brain and abdominal viscera. The incidence of thoracic aortic
aneurysms is approximately 6 cases per 100,000 people/year;
male: female ratio is 2.4:1; the higher frequency is observed
between the fifth and seventh decade of life .
Data of natural history of aortic aneurysms starts to the ‘80s.
Bickerstaff et al.  reported in over 70 patients affected by not
operated expansive or dissecting aneurysms a 5 year survival
of 13% (19% for expansive aneurysms, 7% for dissecting) in
comparison with 5 year survival of 75% observed in a normal
population; 74% of patients had gone to rupture of the aneurysm,
and of these 94% died.
Approximately, 50% of patients with acute untreated ascending
aortic dissection die within 48 h, and those undergoing emergency
surgery have a 20-30% operative mortality. On the contrary,
elective surgery lowers mortality to only 3-5%. Understanding
the pathophysiology of ascending aortic aneurysms can help to
prevent and then to reduce mortality from aortic dissection or
rupture, by indicating timely elective surgery.
Aneurysm diameter (size) is the main indication for elective
surgical intervention, as it correlates strongly with the risk of the
ascending aortic aneurysm to dissect or rupture, but indications
for replacement of ascending aorta are importantly influenced
by etiology, rate of growth of the aneurysm, and family history
The diameter (size) of the aneurysm
Coady et al.  in a study of several hundred patients with
ascending aortic aneurysm found a relationship between size
and risk of rupture of the aneurysm and/or dissection. In patients
affected by an aneurysm of the ascending aorta with maximum
transverse diameter 50-59 mm and in those with a diameter
>60 mm the risk of acute complications (rupture or dissection)
during a 5 year follow-up was 17.8% and 27.9%, respectively, in
comparison with 9.5% for a diameter between 40 and 49 mm. The
risk of rupture increased therefore when the diameter reached
60 mm. For these observations the authors recommend elective
surgery when the diameter of the aneurysm reaches 55 mm.
In fact, the linear risk (per patient/year) of acute complications
(rupture and/or dissection, death) for ascending aortic aneurysms
>60 mm was estimated at 15.6% vs. 6-8% for aneurysms with a
diameter (<60 mm) [4, 5].
Patients with Marfan syndrome exhibit a more rapid growth of
the aneurysm due to the characteristic collagenopathy, with
higher risk of rupture or dissection already to a size of the aortic
dilation smaller than that observed in presence of degenerative
etiology, especially in the presence of family history of acute
complications. Surgical treatment has improved the prognosis of
these patients. In fact, over the years' 70 their life expectancy
was 40 years: cause of death in 60-80% of cases was the rupture
or acute dissection of the aorta, or heart failure from aortic
regurgitation. By the mid-90s in the United States the average
life of Marfan patients was 71 years, just under 73 years of age
healthy population. This improvement was the result of the
prevention (control of hypertension, excluding strenuous physical
activity), the earlier diagnosis, and the elective early surgery.
Family syndromes of aortic aneurysm, not related to Marfan
syndrome, i.e., in autosomal dominant gene transmission,
X-linked or recessive, are at increased risk (about double) of
annual growth and rupture.
In dissecting chronic aneurysms diameter growth is around six
times greater than that of expansive aneurysms, probably due
to the reduced resistance of the aortic wall dissected to the
expansive intraluminal pressure.
An aortic valve disease which itself requires surgery does put more
precociously the indication to the treatment of the aneurysm of
the ascending aorta also already to a diameter >45 mm.
Bicuspid aortic valve represents the most common birth defect
in the adult population, with a prevalence rate of 0.5-2%.
The aortic valve, which has only two cusps, not necessarily is
malfunctioning; however, a normally functioning valve becomes
in the years stenotic and/or insufficient. Aortic stenosis rarely
leads to post-stenotic dilatation of the ascending aorta. Bicuspid
valve indeed is associated with dilation of the root and/or the
above-junctional ascending aorta, depending on the relation to
a genetic defect linked to the activation of metalloproteinases,
responsible for an abnormal structural weakening of the elastic
fibers of the media, with cystic degeneration of the media similar
to that observed in Marfan syndrome [6, 7].
The more recently published Guidelines recommend ascending
aorta replacement a diameter ≥ 55 mm in absence of Marfan
syndrome or other genetic-mediated disorders. On the contrary,
patients affected by Marfan or Bicuspid valve-related aortopathy
(as well as in presence of chronic dissection), should be referred
to elective surgery earlier, when aneurysm dilation of the
ascending aorta reaches 45-50 mm, or 45 mm when patients
have additional risk factors, i.e., size increase >3 mm/year, family
history of dissection, severe aortic regurgitation, or desire of
pregnancy [8, 9].
However, thanks to improved surgical techniques and the use
of prosthetic materials impervious to blood, surgical risk is very
low and elective surgery in patients affected by degenerative
expansive aneurysms can be performed when aortic diameter
reaches 50 mm, in order to eliminate the annual risk of rupture
or acute dissection [8, 9].
Consequently, indications to replace ascending aorta in the
clinical practice are as follows: 1) ascending aortic aneurysm
>5.0 cm in diameter; 2) ascending aortic aneurysm ≥ 4.5 cm
in patients affected by Marfan syndrome or in presence of a
bicuspid aortic valve; 3) ascending aortic aneurysm >4.5 cm in
patients undergoing aortic valve surgery; 4) growth rate of >0.5
cm/year when ascending aorta is <5.0 cm in diameter. In any case,
the surgical indication should be evaluated for each individual
patient depending on risk factors, co-morbidities, body size, or
significant increase of aortic size in short time. In addition, the
study of genetic and molecular markers involved in the formation
of the aneurysm can be helpful in decision making surgery. As
recently published, in 108 patients subjected to ascending aorta
replacement electively and in 26 treated for acute dissection, it
was found that a particular phenotype (type III) of the aortic wall
(i.e., elevated cystic medial degeneration without substitutive
fibrosis) was similarly present either in a subgroup of expansive
aneurysm than in all dissection aneurysms operated on, thus
indicating that kind of phenotype as an optimal biomarker
of dissection, independently of aneurysm diameter or aortic
valve disorder . In a study focused on the relation between
ascending aorta dilation and presence of a bicuspid aortic valve
(BAV), we found that in presence of BAV different genetic and
molecular biomarkers, i.e., severe plurifocal apoptosis of smooth
muscle cells and matrix metalloproteinases, were significantly
involved in aneurysmal dilatation in comparison with the
presence of a tricuspid valve. Identification of BAV at high risk
of aneurysm development can be useful to differently treat this
subset of patients, i.e., with a complete removal of the ascending
aorta, including the aortic root with or without dilation .
Isolated ascending aorta replacement
In the absence of dilation of the aortic root and aortic valve
pathology, the aneurysmal segment of the ascending aorta
above Sino-tubular junction is resected and replaced with a
Dacron cylindrical tubular prosthesis, suitably shaped in order
to avoid "kinking" of the tube into the concavity, by means of
two continuous sutures of polypropylene for the proximal
anastomosis and the distal end. The replacement of the ascending
aorta with a tubular prosthesis also allows the reconstruction of
the Sino tubular junction with re-suspension of the aortic valve
cusps, in order to correct a failure from eccentric stretch of the
commissures. To stabilize and improve this correction, it can be
added aortic valve repair.
In Marfan patients the aortic root, although not dilated at the
time of replacement of the supra-junctional ascending aorta, also
needs to be replaced for the risk of subsequent expansion and
need for further intervention.
Separate aortic valve and ascending aorta replacement
Ascending aortic aneurysms, with normal sinuses and aortic
annulus, require replacement of the ascending aorta from the
Sino-tubular ridge to the origin of the innominate artery with
a Dacron tube graft similarly to the isolated ascending aorta
replacement. In addition, the diseased aortic valve is replaced
separately with a mechanical or biological prosthetic valve.
Complete replacement of the ascending aorta
Bentall-De Bono operation  is suggested to be a surgical
"gold standard" for the treatment of aneurysms of ascending
aorta involving the aortic root. This procedure can be done in
presence of a significant dilation of the aortic root (diameter >50
mm for degenerative disease, or ± 45 mm in presence of bicuspid
© Under License of Creative Commons Attribution 3.0 License
Journal of Vascular and Endovascular Surgery
aortic valve, Marfan syndrome or other genetic disorders. In
our experience, Bentall operation is performed also in presence
of an asymmetrical dilatation of the aortic root (i.e., although
the aortic root diameter does not reach 45 mm, one or two of
Valsalva coronary sinuses are affected by a marked dilation and/
or in presence of significant coronary ostium/ostia dislocation).
All Marfan patients should undergo replacement of the ascending
aorta including aortic root. The procedure is usually done with a
composite graft consisting of a mechanical valve inserted into a
collagen- or gelatin-impregnated preassembled Dacron tubular
graft, or suturing on the tubular graft a biological prosthesis.
Coronary artery ostia are reimplanted as buttons (“button
In the early 90s, after 30 years of replacement surgery, were
proposed, in selected groups of patients, some techniques
of conservative surgery ("valve-sparing") of the aortic valve,
alternatively to the Bentall operation. These techniques have
the advantage of avoiding complications related to the implant
of a valvuar prosthesis, both mechanical (bleeding complications
anticoagulation therapy-related) and biological (redo operation
due to structural valve degeneration). The native aortic valve can
be spared if, in presence of dilation of the Valsalva sinuses, the
leaflets are normal and aortic insufficiency is secondary to dilation
of the Sino-tubular ridge or aortic root, without structural valve
alterations (i.e., calcifications, stenosis, marked prolapse of cusps,
excessive diastases of cusps in presence of anulo-aortic ectasia).
Two techniques have been proposed by Yacoub (aortic root
“Remodeling”)  and David (aortic valve “Reimplantation”)
[14, 15]. Both interventions replace the ascending aorta with
coronary ostia reimplantation on the Dacron tubular graft, while
preserving the native valve, thus restoring its continence. Without
implantation of a prosthetic valve, "valve-sparing" operations
give the prospect of a better quality of life (not being required
anticoagulation with its complications) and a lower risk of
endocarditis. The major limit of these procedures is represented
by the potential progression of aortic valve insufficiency during
follow-up that may require a late redo operation.
From January 2015 to February 2016, at the Cardiac Surgery Unit
of the Tor Vergata University of Rome, on a total of five hundred
and ninety-two open heart procedures, elective surgery on the
ascending aorta was performed in 83 patients (15%). Mean age
of patients was 64 ± 14 years, mean EuroSCORE II 4.7%.
Bentall procedure was performed more frequently (50 cases,
60%). There was no operative mortality; in 3 patients (4.1%)
postoperative course was complicated by low output syndrome,
in 3 (4.1%) by re-exploration for bleeding, in 1 (1.2%) by need for
pacemaker implantation, in 1 (1.2%) by early endocarditis. Type
of procedures and surgical times are summarized in Tables 1 and 2.
Ascending aortic aneurysm is a lethal disease [16, 17]. Elective
surgical repair remains the gold standard for the management
of symptomatic aneurysm or asymptomatic aneurysm with a
diameter ≥ 5.5 cm [8, 9]. However, considering the low operative
risk for elective surgery, in the current clinical practice and specific
patient-related factors, such as molecular and genetic biomarkers
involved in aortic aneurysm development [10, 11], appropriate
preventive surgery can be recommended in a timely manner
(aortic diameter >5.0 cm). Lower threshold of aortic diameter
for surgery should be considered for patients with aortopathy
related to congenital disorders (i.e., Marfan syndrome, bicuspid
aortic valve), and Bentall operation can be considered the gold
standard surgical therapy in this subset of patient population.
Type of procedure
No. pts (%)
Ascending aorta replacement (supra-junctional)
+/- aortic valve sub-commissural valvuloplasty
Ascending aorta replacement+aortic valve
*Mitral valve surgery, CABG
Ascending aorta replacement
(supra-junctional) +/- aortic
valvuloplasty, minutes (mean
+ aortic valve replacement,
minutes (mean +/- SD) +/-
100 +/- 27
122 +/- 31
Bentall +/- associated
procedures, minutes (mean
105 +/- 28
*p<0.0001 vs. Bentall operation times
**p<0.001 vs. Ascending aorta repair associated with aortic valve
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