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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 27, No 6, November/December 2016
342
AFRICA
ascending aorta. One possible cause of dilation is haemodynamic
flow disturbance in the aorta beyond the stenotic valve. The
second possibility is a genetic predisposition to aortic dilation.
We performed AVR and RAA in 36 patients and Bentall in
11 patients. In recent years, ascending aortic surgery has been
performed in an increasingly elderly population, with a 15–40%
incidence of co-existing CAD. Therefore pre-operative coronary
angiography is routinely performed in elective patients, and
concomitant CABG has begun to be performed more frequently,
with an incidence of between 11 and 25% in some larger
aortic surgery studies.
10-12
We performed CABG and RAA in 25
patients, and eight underwent both CABG and AVR with RAA.
In our study it was shown that the aneurysm was discovered in
patients who underwent coronary angiography for symptoms of
ischaemia.
Ueda
et al.
identified incomplete coronary revascularisation
as a risk factor for cardiovascular events.
13
Atherosclerosis and
inflammation are important factors in the development of valve
stenosis and CAD.
14,15
CAD is also a common finding in patients
undergoing endovascular or surgical repair of descending,
thoraco-abdominal or abdominal aortic aneurysms.
16,17
In older
patients undergoing planned aortic reconstruction, pre-operative
coronary angiography should be performed and appropriate
revascularisation must be performed.
18
We suggest that surgery
of the ascending aorta with concomitant CABG may increase
the mortality rate.
A study in the UK showed that the overall mortality rate was
3.2% for isolated aortic valve procedures and 6.8% for aortic
valve procedures with concomitant CABG.
10
However, Ueda
et
al.
reported that complete revascularisation of major coronary
arteries with significant stenosis is essential to reduce post-
operative cardiac events.
13
In a report by Houel and colleagues from France, the type of
surgery had no effect on long-term survival, but AVR + RAA
was associated with more aortic wall complications (aortic
root dilation and false aneurysms) than the Bentall procedure.
However, AVR + RAA was performed in patients with Marfan
syndrome and others with aortic root aneurysm.
19
Yun and colleagues compared 255 patients who underwent
AVR + RAA, and 135 patients who underwent the Bentall
procedure between 1965 and 1995.
20
In the AVR + RAA group,
the surgical mortality rate was 15.3%. Survival at 10 years was
51
±
3% and at 15 years it was 36
±
3%. Urbanski and colleagues
reported a similar operative risk and late mortality and morbidity
among 100 patients who underwent AVR + RAA or a modified
Bentall procedure using Carbomedics mechanical valves.
21
Sioris and associates reported no differences in peri-operative
mortality rate or freedom from re-operation in 133 patients after
10 years between AVR associated with RAA and a modified
Bentall procedure.
22
Rizzoli and colleagues, in their study of
809 patients undergoing AVR, including 110 RAA patients,
reported a 30-day mortality rate of 5.5%.
23
Garrido-Olivares
et
al
. reported on combined AVR and supracoronary RAA in 89
patients with an operative mortality rate of 2.3%.
24
Simple AVR does not prevent the enlargement of the
ascending aorta. Patients who have dilated ascending aortas at
the time of AVR are at high risk of developing postoperative
ascending aortic complications.
25
This is not because of the
primary surgery but due to intrinsic changes in the aortic wall.
The time interval between initial AVR and late ascending aortic
events ranged from two to 18 years. In a study by Tsutsumi
et
al.
,
50% of patients who developed late ascending aortic events
during the follow-up period died.
26
Replacement of the ascending aorta does not significantly
increase the mortality risk. Moreover, AVR cannot reduce
the risk of fatal aortic complications. Some authors reported
that in patients with bicuspid aortic valve after AVR only, the
aorta continues to enlarge and aorta-related complications
increase.
27,28
It was shown that concomitant RAA during AVR
did not increase the rate of morbidity and mortality in the
short-term, despite an increase in aortic cross-clamp and total
cardiopulmonary bypass times.
29
Our findings are compatible
with these studies.
The goal should be to avoid the catastrophic consequences
of acute aortic dissection or rupture. The decision for surgical
treatment is primarily based on comparative estimation of
the natural prognosis of the disease versus the prognosis with
treatment.
30
The spontaneous prognosis is related to aortic
diameter, mechanical properties of the vascular wall, and blood
pressure. Aortic diameter has been best studied and is considered
the primary prognostic parameter.
30
The prognosis after treatment
depends on complications of surgery and its mortality risk. In our
study the mortality rate was increased insignificiantly.
Type I aortic dissection occurs in 0.6% of patients late after
AVR.
31
Thirteen per cent of patients with acute type I aortic
dissections had a history of previous AVR.
32
In contrast to
previous AVR, a history of CABG alone is not an independent
risk factor for type I aortic dissection.
33
However, diameter is not
specific enough to affect the risk of dissection, and the law of
Laplace must be taken into account; the incidence of dissection
and rupture increases with increasing size of the ascending aortic
aneurysm.
34
The primary aim of prophylactic replacement is to
prevent this catastrophic complication.
Our decision to replace the ascending aorta was based on
the size of the aortic diameter. Patients with ascending aortic
diameter more than 45 mm underwent concomitant ascending
aorta replacement.
In their study, Davies
at al
. reported that relative aortic
size is more important than absolute aortic size in predicting
complications. A new measurement, the aortic size index, which
takes into account both aortic diameter and body surface area,
was used for calculating the risk of negative events. According to
them, increasing aortic size index was a significant predictor of
increasing rates of rupture.
35
Lentini
at al
. reported their initial experience for ascending
aortic surgery with or without valve or root surgery via a mini-
sternotomy approach. Surgery of the aortic root and ascending
aorta has traditionally been performed via a conventional
median full sternotomy. The development of minimally invasive
surgical techniques reduces surgical trauma, length of mechanical
ventilation and ICU stay, improves post-operative outcomes and
also has cosmetic benefits.
36
Especially in high-risk patients, a mini-sternotomy approach
can improve recovery of respiratory function and allow earlier
extubation, reducing ICU and hospital stay in complex aortic
surgery. There are a few examples of this procedure: Tabata
et al
.
37
and Perrotta
et al
.
38
reported on a Bentall procedure
with mini-sternotomy, using this approach on both elective
and emergency patients, and in redo surgery. Svensson
et al.
reported 36 patients operated for ascending aorta replacement,