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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 28, No 2, March/April 2017
AFRICA
119
due to genetic causes, as seen in Marfan syndrome and Ehlers
Danlos type 4.
2
Knowing the aetiological factors causing aneurysms
may contribute to slowing down the pathogenic process and
determination of a treatment modality. Aortic valve pathologies,
hypertension, smoking, alcoholic beverages, diabetes mellitus,
cross-clamping, cannulation site, aortic suture lines, and
proximal anastomosis of coronary artery grafts have been held
responsible for the development of aortic aneurysms. Formulae
suggested to estimate the growth rate of aortic aneurysms
demonstrate differences based on aetiological, regional and
geographic conditions.
3
This study was designed to determine the short- and long-
term effects of proximal aortic anastomosis performed during
isolated coronary artery bypass grafting (CABG) in patients
with dilatation of the ascending aorta who did not require
surgical intervention.
Methods
The study, to be performed on patients with dilatation of the
ascending aorta who would undergo CABG surgery in the
clinics of Dr Siyami Ersek Thoracic and Cardiovascular Surgery
Training and Research Hospital between 1 June 2006 and 31 May
2014, was initiated after approval of the local ethics committee
was obtained. The objective of the study was explained to all
patients and their written approval was obtained. The study was
completed with 192 patients (38 female and 160 male; mean age
62.1
±
9.2 years; range 42–80 years) who had to undergo isolated
CABG surgery.
Patients with a diagnosis of connective tissue disease, those
who had undergone additional cardiac surgery, re-operation,
cases with aneurysms at various regions of the aorta or peripheral
arteries, individuals with extremely calcified aortae and congenital
or acquired aortic valve pathologies, and patients lost to
postoperative follow up were excluded from the study. Patients
who had cardiopulmonary bypass (CPB) and isolated CABG and
those whose ascending aortic diameter was 40–45 mm (mean: 42.1
±
1.8 mm) at its widest region, determined using transthoracic
echocardiography (TTE), were included in the study.
The patients were divided into two groups. In group 1 (
n
=
114, 59.4%), saphenous vein and left internal mammarian
artery (LIMA) grafts were used, and proximal anastomosis was
performed on the ascending aorta. In group 2 (
n
=
78, 40.6%),
LIMA and right internal mammarian artery (RIMA) grafts were
used, and proximal aortic anastomosis was not performed.
Clinical and demographic data of the patients related to
age and gender, left ventricular ejection fraction (LVEF),
hypertension (HT), diabetes mellitus (DM), chronic obstructive
pulmonary disease (COPD), chronic renal failure (CRF),
previous myocardial infarction (MI), hyperlipidaemia, peripheral
artery disease (PAD), stroke, smoking status and alcohol use
were recorded. Pre-operatively and in the first and third years
postoperatively, the ascending aorta was measured and recorded
using TTE diameters at four different regions (annulus, sinus of
Valsalva, sinotubular junction and tubular aorta). Postoperative
monitoring of the patients was achieved via communication with
patients by telephone.
Under routine intra-operative anaesthesia, a median
sternotomy was performed on all patients. The bypass grafts
(LIMA, RIMA, saphenous vein) were prepared. Following
heparinisation (3 mg/kg IV), an arterial cannula was inserted
into the ascending aorta and a two-stage cannula was implanted
into the right atrium. Using a roller pump and membrane
oxygenator, we proceeded with CPB.
During CPB, activated coagulation time was maintained over
400 seconds. Moderate levels of systemic hypothermia (28–30°C)
were used. Pump flow rate and perfusion pressure were held at
2.2–2.4 l/min/m
2
and 50–85 mmHg, respectively. Following cross-
clamping of the aorta, cold blood cardioplegia was performed
in the antegrade direction to achieve cardiac arrest. After
completion of the distal anastomosis, cardioplegic solution
was delivered through the saphenous vein graft and myocardial
protection was maintained. After placement of the side clamps,
proximal anastomosis was performed on a beating heart.
The patients were extubated in the intensive care unit within
three to six hours of the operation. As criteria for extubation, the
patient had to be wide awake, haemodynamically stable, and the
amount of hourly drainage had to have dropped to acceptable
amounts. During the postoperative period, patients who did not
develop major complications were followed up in the ward. All
patients were discharged after an average of seven to nine days.
As a control, TTE was performed at one and four weeks
postoperatively and no pathological evidence was found. TTE
was repeated at one and three years postoperatively. The TTE
procedure was performed by a cardiologist blinded to the
grouping of patients. Before the procedure, the patients were
informed about the procedure and their approvals were obtained.
Measurements were made at four different regions of
the ascending aorta. During TTE, ventricular and valvular
dysfunction (if any) were also determined. Left ventricular
end-diastolic (LVEDD) and end-systolic diameters (LVESD),
LVEF, and systolic and diastolic volumes were also determined.
In our study we chose TTE rather than CT angiography as TTE
provides information on ventricular and valvular function and
evaluates the aortic annulus and sinotubular junction more
effectively, in addition to its lower cost and non-toxicity.
Statistical analysis
For statistical evaluations, the SPSS statistical program (SPSS
for Windows, version 11.0, SPSS Inc, Chicago) was used. If
all measured data demonstrated a normal distribution, they
were expressed as mean
±
standard deviation; if not, they were
indicated as median (minimum–maximum) values. Numerical
data were presented as percentages (%).
For data obtained with measurements, normality of
distribution was evaluated using histograms or the Kolmogorov–
Smirnov test and their homogeneity were assessed with Levene’s
test for equality of variance. For data with normal and
homogenous distribution, intergroup difference was evaluated
using the Student’s
t
-test, while data with non-normal and
non-homogenous distributions were evaluated using the Mann–
Whitney
U
-test.
Intergroupdifferencesamongthenumericaldatawereevaluated
with parametric or non-parametric Pearson’s chi-squared and
Fisher’s exact test, based on the parametric or non-parametric
distribution of data, respectively. In comparisons of mean values
of dependent groups, Friedman’s
S
-test was used. Data with a
p
-value
<
0.05 was accepted as statistically significant.