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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 27, No 3, May/June 2016
148
AFRICA
A reasonable alternative approach is choosing balloon size
according to the maximal inter-commissural distance of the
mitral valve as provided by echocardiography. This is a more
direct and conservative method of balloon sizing to avoid
possible mistakes when determining the size of the balloon, and
to prevent possible complications in the procedure.
The aim of this study was to assess the early haemodynamic
and echocardiograhic results of BMV according to these two
different types of Inoue balloon selection strategy.
Methods
Between 1 January 2006 and 31 December 2011, 128 consecutive
symptomatic patients were seen with moderate to severe
mitral stenosis (MVA
<
1.5 cm
2
), whose valve morphology was
suitable for BMV and who had no contraindications for BMV.
Symptomatic and asymptomatic patients were included who had
a pulmonary artery systolic pressure of
>
50 mmHg at rest or 60
mmHg with exercise in the presence of favourable morphological
criteria of the mitral valve, derived from the echocardiographic
Wilkins scoring system.
11
Patients were considered eligible if they
were aged 18 years or older.
Exclusion criteria were mild mitral stenosis, a Wilkins score
of
>
10, moderate or severe mitral regurgitation, any moderate or
severe valvular heart disease other than mitral stenosis, a history
of coronary artery disease, heart failure, pulmonary embolism,
congenital heart disease, chronic kidney disease and current
pregnancy.
Patients were randomised into two groups. One group was
allocated to conventional height-based balloon reference sizing
(the HBRS group) and the other was allocated to balloons sized
by the echocardiographic measurement of the diastolic inter-
commissural diameter (the EBRS group). BMV was performed
in all patients.
All patients were informed about the study, and written
consent was obtained. The study was approved by the institution’s
ethics committee and performed in accordance with the Helsinki
Declaration.
Echocardiography
In accordance with the recommendations of the American
Society of Echocardiography, all transthoracic echocardiographic
(TTE) examinations were performed with the patient lying
in the left lateral decubitus position, and two-dimensional
images were recorded and measured in the apical four-chamber,
two-chamber, and parasternal long- and short-axis views.
15
Echocardiographic examinations were performed by two
independent cardiology specialists, blinded to the outcome of
BMV, in the echocardiography laboratory before and one month
after BMV.
B-mode, two-dimensional Doppler and colour-flow Doppler
echocardiographic evaluations were performed using a Siemens
Acuson CV70 system (Siemens AGMedical Solutions, Erlangen,
Germany) with a 2.5–4.0-MHz transducer with second harmonic
capabilities. Transoesophageal echocardiographic (TEE)
examinations were performed on all patients with a 5-MHz
multiplane endoscopic probe.
MVAs were calculated using the direct planimetry and
pressure half-time method. Diastolic trans-mitral gradients
were measured by continuous-wave Doppler echocardiography.
Systolic pulmonary artery pressure (sPAP) was measured with
continuous-wave Doppler. Tricuspid regurgitation velocity (V)
was recorded from any view and used to determine sPAP (sPAP
=
4V
2
+
right atrial pressure). V is the maximum velocity of the
tricuspid valve regurgitant jet, measured by continuous-wave
Doppler, added to the estimated right atrial pressure. Right
atrial pressure was calculated using the caval respiratory index,
as described by Kircher
et al.
16
Finally, themaximal inter-commissural distance was measured
on the parasternal short-axis view from the anterolateral to
posteromedial commissures in mid-diastole. The degree of mitral
regurgitation and the presence of concomitant valvular heart
disease and left atrial clot were also determined.
Catheterisation and valvuloplasty
Cardiac catheterisation was performed using Siemens AXIOM
Artis dFC equipment (Siemens AG, Medical Solutions, Erlangen
Germany). The right and left heart haemodynamic study was
performed to evaluate sPAP and mitral valve pressure gradients.
In the HBRS group, balloons were selected using the height-
based reference size by calculating according to the standard
height-based formula [0.1
×
height (cm)
+
10]. In the EBRS
group, balloons were selected according to the echocardiographic
inter-commissural distance measurement in mid-diastole.
The classic antegrade Inoue balloon technique was used for
BMV by two experienced cardiologists in a standard and similar
fashion. Procedures were performed with TEE guidance. After
the atrial septostomy and appropriate septal dilation, 100 IU/kg
of heparin was administered to achieve an activating clotting time
of
>
250 seconds. Left ventriculography was performed before
and after BMV to evaluate mitral regurgitation. A successful
BMV was defined as an uncomplicated procedure yielding a
final mitral valve area of
>
1.5 cm
2
and post-valvuloplasty mitral
regurgitation of
<
3
+
.
Statistical analysis
Continuous variables are given as mean
±
SD. Categorical
variables were defined as percentages and compared with the
chi-square test to compare the measurements before and after
BMV, and a Student’s paired
t‑
test was used. A probability value
of
p
<
0.05 was considered significant, and two-tailed
p
-values
were used for all statistics.
Results
In this study, 128 patients participated. In 65 patients, Inoue
balloon sizes were calculated according to HBRS, while in the
remaining 63 patients, sizes were provided by EBRS. The study
patients’ baseline clinical, echocardiographic and catheterisation
characteristics are shown in Tables 1, 2 and 3.
The mean age of the patients was 32 years in the HBRS
group and 31 in the EBRS group, and there was no statistically
significant difference (
p
=
0.16) between the groups; 72.7% of
the patients were female. There was no difference between the
groups in terms of weight and height (
p
=
0.64 and
p
=
0.62,
respectively). Therefore it can be considered that both groups
were similar in terms of body mass index.