CARDIOVASCULAR JOURNAL OF AFRICA • Vol 24, No 5, June 2013
162
AFRICA
2005 to February 2010. Of 60 patients, 54 (12 male and 42
female) underwent successful transcatheter closure (device in
proper position and no or trivial shunt across the septum) and
were included in our study. The procedure failed in four cases
due to insufficient support of the device by the interatrial septum,
and two other patients underwent open-heart surgery because the
device had embolised to the left atrium.
Before the procedure, all the patients underwent a
comprehensive transoesophageal echocardiographic study to
investigate the morphology of the defect. Based on availability,
36 patients underwent ASD closure using the Amplatzer septal
occluder, whereas 18 patients had its Chinese copycat, the Heart
®
ASD occluder device. Pre-discharge echocardiography was done
24–48 hours after the procedure.
Echocardiographic assessment was conducted in all patients,
using a combination of two-dimensional (2D) transthoracic
(Vingmed GE, Horten, Norway, 3.5-MHz transducer) and
transoesophageal echocardiography (Vivid-7, Vingmed GE,
Horten, Norway, 7-MHz transducer). All patients were reassessed
between 24 hours and six weeks after PTMC via transthoracic
echocardiography. All echocardiographic measurements were
assessed based on the American Society of Echocardiography
(ASE) guidelines and standards.
TEE was performed within the six-month period before the
transcatheter occlusion procedure, to exclude other associated
cardiovascular deformities and to investigate the suitability
of the ASD size and its surrounding rims for transcatheter
closure. Under local anaesthesia, 2D TEE was performed and
the diameter of the defect was measured in various planes to
determine the maximal defect size. The most useful views for
defect sizing included the mid-oesophageal four-chamber view
at 0°, the short-axis view at 45–60°, and the bicaval long-axis
view at 90–110°.
The maximal diameter of the defect was acquired during
the cardiac cycle and recorded. The rims of the defect were
measured from the margins of the defect to the inferior vena
cava, superior vena cava, right upper pulmonary vein, tricuspid
and mitral valves, aorta, and coronary sinus, wherever possible.
Exclusion criteria for device closure comprised (1) ASD rims
≤
5
mm, except for the anterior superior rim, and (2) multiple ASDs
as assessed by TEE.
Balloon sizing and deployment of the septal occluder
Vascular access was obtained from the femoral vein. The tubular
sizing balloon (AGA Medical Corporation, Golden Valley, MN,
USA) was introduced over a wire that had been placed through
the ASD into a left pulmonary vein. Under transoesophageal
echocardiographic guidance, the balloon was inflated in the left
atrium with increasing quantities of diluted contrast medium and
was then pulled back against the ASD. It was thereafter deflated
to reach a size sufficient to enable it to be pulled into the right
atrium through the defect.
The BOD was defined as the balloon size that completely
occluded the ASD and prevented any shunt across the defect
without deformity of the balloon. The balloon diameter was
measured directly on the screen connected to fluoroscopy and by
TEE. Device size was selected with a waist diameter similar to
or up to 3 mm larger than the BOD measurement, according to
the flexibility of the surrounding rims. Subsequently, the device
was inserted and deployed under TEE guidance.
The technique of device closure was similar to those described
in the literature.
6,27
Based on availability, the Amplatzer septal
occluder (AGA Medical Corporation, Golden Valley, MN,
USA) or its Chinese copycat, the Heart
®
ASD intracardiac patch
occluder (Lifetech Scientific INC, Shenzhen, China), were
implanted in patients. After releasing the device from the cable,
a final TEE examination was undertaken to ascertain the position
of the device and any residual shunting.
Successful ASD closure was defined as a device in the proper
position with no or trivial leak, as determined by TEE in the
catheterisation laboratory. Following the procedure, the patients
were sent to a recovery room with ECG monitoring for 12 hours
and were discharged two days after the procedure. All patients
underwent TTE before discharge.
Statistical analysis
The numerical variables are presented as mean
±
SD (standard
deviation), while the categorical variables are summarised by
raw numbers and percentages. The paired
t
-test was used to
compare ASD size by TEE and by the diameter of the deployed
device or via balloon sizing. The linear regression analysis was
performed to demonstrate the relationship between TEE size and
BOD and also between TEE measurement and final size of the
implanted device.
The measured and calculated (predicted) ASD device
diameters were further examined by plotting scattergrams
and developing regression lines. The statistical software SPSS
version 13.0 for Windows (SPSS Inc., Chicago, IL) was used
for the statistical analysis and a
p
-value
≤
0.05 was considered
statistically significant.
Results
Fifty-four patients (12 male and 42 female) aged nine to 71
years fulfilled the inclusion criteria. All the patients underwent
successful ASD closure under 2D TEE monitoring. Maximum
defect size ranged between 10 and 30 mm. The devices were
deployed appropriately (range of size: 14–39 mm) with no
residual shunt across the septum except in one patient who had a
trivial shunt just after the occlusion procedure.
Under pre-discharge TTE evaluation, there was no report
of any shunt; and mild pericardial effusion occurred in three
patients, while moderate pericardial effusion was detected in one
patient. In one subject, there was mild compressive effect on the
aortic root and in another there was compressive effect on the
aortic root, at the base of the anterior mitral leaflet and base of
the septal tricuspid leaflet. All these patients were followed up
meticulously and these events resolved spontaneously.
Demographic data, and echocardiographic and ASD
characteristics of all patients are summarised in Table 1. The
mean of TEE-derived maximum size of the defect was lower
than the mean of the BOD (17.8
±
4.5 vs 22.1
±
5.1 mm;
p
<
0.001) and also lower than the mean size of the implanted device
(17.8
±
4.5 vs 23.3
±
5.1 mm;
p
<
0.001) (Table 1). There were
good correlations between maximum defect size measured on
TEE and via balloon sizing (BOD
=
0.898
×
TEE defect size
+
6.212,
R
=
0.824;
p
<
0.001) and between TEE diameter and the
final size of occluded device (device size
=
0.928
×
TEE defect
