Aortic Valve Annular Dimension
in Indian Population
Anatomy Section
DOI: 10.7860/JCDR/2013/5776.3329
Original Article
HANNAH SUGIRTHABAI RAJILA RAJENDRAN1, SUDHA SESHAYYAN2, ASHOK VICTOR3, GANGADEVI RAJAPANDIAN4
ABSTRACT
Aim: The Aortic Valve (AV) annular dimension with respect to the
Body Surface Area (BSA) of the Indian population is compared
against the standard values. Presence of discrepancies can lead
to patient prosthesis mismatch during aortic valve replacement
surgeries.
Methods: This study was conducted on 406 subjects. AV
diameter was examined by using parasternal long axis view,
where the imaging plane transects the AV in an anteroposterior
direction and its x axis is aligned parallel to the long axis of aorta.
Data were statistically analysed with western population.
Results: The AV dimension ranged from 12.2 mm to 21.2 mm
,
in the BSA range of 0.6 to 1.9 m2 showing a linear increase in
diameter with increasing BSA. There was an increase of about
2 mm, from 0.61 - 0.7 m2 BSA to 0.71 - 0.8 m2 BSA. A linear
increase which ranged from 0.3 to 1 mm was observed for BSA
which ranged from 0.81 m2 to 1.2 m2. In the BSA range of 1.21 –
,
1.3 m2 there was an increase of 1.5 mm. A steady increase which
ranged from 0.4–1 mm was observed in the BSA which ranged
from 1.31- 1.9 m2.
Conclusions: There is a significant difference between Indian and
western population in the aortic dimension, in the body surface
ranges of 0.61-0.7, 1.11-1.2, 1.21-1.3, 1.51-1.6, 1.61-1.7, 1.711.8 and 1.8-1.9 m2. In the range of 1.21-1.3 m2, the diameter was
larger than standard, whereas in all the other ranges, AV diameter
was smaller than standard values. BSA, as a good predictor of
AV dimension, has also been proved.
Key words: Aortic valve annulus, BSA, Indian population
INTRODUCTION
Cardiac valves are replaced in either stenotic or regurgitant lesions.
To replace the valve and to know the severity of the regurgitant lesion,
the normal valve annular size should be known. Patient prosthesis
mismatch is a complication if the patient’s annulus is different
from the size of the prosthetic valve. The term, ‘patient prosthesis
mismatch’ was introduced by Rahimtoola [1], who stated that an
obstructive aortic prosthetic valve with an effective orifice area of
less than 0.8cm2/m2 could increase the operative mortality and
impair functional recovery after an aortic valve replacement. Philippe
Pibarot and Jean G Dumesnil [2] stated that a patient–prosthesis
mismatch was associated with worse haemodynamics, a reduced
regression of LV hypertrophy, more cardiac events and increased
short term and long term mortalities after valve replacements.
Habbal ME, Somerville J [3], in 1989, showed that if the dimensions
of cardiac valves were corrected with body surface area (BSA),
the two dimensional echo and surgical measurements could be
identical. Thus, BSA is a useful tool for estimating normal aortic valve
size. Capps SB, Elkins RC and Frank DM [4] showed that in males,
the aortic valve diameter was 23.1 ± 2mm and that in females, it
was 21.0 ± 1.8 mm and that the pulmonary valve diameter was
26.2 ± 2.3mm in males and that it was 33.9 ± 2.2mm in females. The
indexed aortic valve area was 2.02 ± 0.52cm2/m2 and pulmonary
valve area was 2.65 ± 0.52cm2/m2. They showed that aortic valve
and pulmonary valve diameter were closely related to body size.
When a valve is being replaced, a patient–prosthesis mismatch
can result in restrictive changes of the heart, due to the prosthetic
valve being smaller than the annular size of the valve. The annular
dimensions depend on age, sex and individual’s BSA. (Capps SB,
Elkins RC, Frank DM [4] and ZHU Dan and ZHAO Qiang [5]) These
dimensions are of utmost significance for repair and replacement
of cardiac valves. These parameters have been already studied in
the western population and the standard measurements have been
1842
derived from them. The prosthetic valves which are available for
aortic valve replacement in India are all selected according to the
BSA of the individual. These standard AV annular diameters which
are derived against the BSA, are all indexed only for the western
population. But the actual AV diameter for the same BSA may vary
between the western population and Indians. Hence, a study on
Indian population was undertaken, to compare the aortic valve
annulus diameter with respect to the BSA, with the available data of
western population.
MATERIAL AND METHODS
This study was conducted on patients who visited the Cardiology
Out Patients Department, after getting their consents. The total
number of subjects was 406. The subjects who had normal
echocardiograms were only taken up for this study. Any other gross
or pathological diseases were also ruled out before the subjects
were chosen for this study. Each subject’s height in centimetres and
weight in kilograms were recorded. This study was conducted on all
406 subjects by doing echocardiograms. The dimensions of annuli of
aortic valves were measured by two dimensional echocardiograms,
as shown in [Table/Fig-1 and 2]. Echocardiogram which was used
in this study was a spatially oriented B mode scan which provided a
cross-sectional or a two dimensional image of an object.
The aortic valve was examined by using the parasternal long axis
view during early systole. In this view, the imaging plane transects
the aortic valve in an anteroposterior direction and it X-axis is aligned
parallel to the long axis of aorta. Because the aorta is normally to the
right of the transducer when it is in the parasternal location, the long
axis plane is usually oriented, such that it passes through the right
and noncoronary aortic leaflets. On the echocardiogram, anteriorly,
there are prominent echo signals from the anterior chest wall and
anterior right ventricular wall and posteriorly, there are echoes from
the posterior wall of the left atrium. The two parallel signals which
Journal of Clinical and Diagnostic Research. 2013 Sept, Vol-7(9): 1842-1845
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Hannah Sugirthabai Rajila Rajendran et al., Aortic annulus in Indians
[Table/Fig-1]: RV–Right Ventricle; LV- Left Ventricle; AO–Aorta;
LA–Left Atrium
move synchronously with the cardiac cycle are the echoes from
the anterior and posterior walls of the aortic root, respectively. The
right ventricular and the left atrial cavities are visualised as relatively
echo-free spaces between the anterior right ventricular wall and
the posterior wall of the left atrium. In the area which represents
the aortic root, echoes are found to originate from the aortic valve
cusps. In diastole, these are visualised as a single central line which
represents the cusps in the closed position. Frequently, when the
gain of the instrument is reduced, the central line is visualised as two
or three thin echo signals with a hair line separation (I mm or less). At
the onset of ventricular systole, the central line is rapidly replaced by
two parallel lines. These latter echoes which lie in close proximity to
those from the inner wall of the aortic root represent the aortic valve
cusps in the open position. At the onset of ventricular diastole, they
come together to fuse and form the central line, thus giving rise to
the box-like configuration during systole.
The BSA was calculated by using
Mosteller’s formula: [6] BSA (m2) =
RESULTS
The results of all 406 patients were recorded and the average
was calculated. The average aortic valve diameter, along with the
standard deviation, was computed against the BSA. The BSA
values were categorised as were given by Kirklin/ Barratt-Boyes [7].
As observed in [Table/Fig-3], the whole range of aortic valve annulus
varied between a minimum of 12.2 mm to a maximum of 21.2 mm
in the BSA ranges of 0.6 to 1.9 m2 The aortic valve was examined
by using the parasternal long axis view [Table/Fig-1]. Aortic valve
shows a linear increase in diameter with increasing BSA, as can
be seen clearly in the [Table/Fig-3]. There was an increase of about
2 mm from 0.61-0.7 m2 BSA to 0.71– 0.8 m2 BSA. Afterwards, a
linear increase in diameter which ranged from 0.3 to 1mm was seen
for body surface area which ranged from 0.81 m2 to 1.2 m2. In the
next range of BSA of 1.21 –1.3 m2, there was an increase of 1.5
mm. Then, a steady increase which ranged from 0.4–1 mm was
observed in the body surface which ranged from 1.31–1.9 m2.
DISCUSSION
The obtained aortic valve dimensions were categorised according
to the BSA and were tabulated. The standard values which were
derived from Kirklin/ Barratt- Boyes [6] were compared with the
study data. The statistical tests of significance were done for both
Indian and standard values of aortic valve annuli. The statistical test
of correlation was also done to prove that BSA was a good predictor
of the aortic valve dimensions.
BSA
[Table/Fig-2]: Aortic valve annulus
Study Population
Standard Values
0.61 - 0.7
12.2 ± 0.4
13.5 ± 1.3
0.71 - 0.8
14.1 ± 1.8
14.1 ± 1.1
0.81 - 0.9
14. 5 ± 1.5
14.6 ± 1.5
0.91-1.0
15.6 ± 1.2
15.6 ± 1.3
1.01 - 1.1
16.1 ± 1.3
16.3 ± 1.5
1.11 - 1.2
16.6 ± 0.5
17.2 ± 1.9
1.21 - 1.3
18.1 ± 1.6
17.1 ± 1.6
1.31 - 14
18.5 ± 2.7
18.7 ± 1.7
1.41 - 1.5
18.8 ± 1.3
19.1 ± 2.3
1.51 - 1.6
19.7 ± 1.5
20.7 ± 2.4
1.61 - 1.7
19.8 ± 0.8
20.8 ± 2.1
1.71 - 1.8
20.8 ± 0.9
21.5 ± 2.0
1.81 - 1.9
21.2 ± 0.9
22.3 ± 2.1
[Table/Fig-3]: The mitral valve and body surface area standarized
diameters of aortic annulus [mm]
BSA: Body Surface Area in m2.
Journal of Clinical and Diagnostic Research. 2013 Sept, Vol-7(9): 1842-1845
Body surface area, which is a measure of the individual’s height and
weight, is used as an index for annular dimensions of cardiac valves.
There are studies which have shown a definite correlation between
valve annular size and BSA. King DH [8], in 1985, stated that the
best predictor for valve annular diameter was a logarithmic function
of BSA, with a calculated correlation coefficient which ranged from
0.9–0.93 for 3 annular dimensions. In contrast, Singh B and Mohan
JC [9] stated that aortic valve dimension does not correlate directly
with the BSA. But the aortic valve dimensions showed a steady
increase with increasing BSA [Table/Fig-3] in this study.
Gutgesell HP and French M [10] showed that the valve dimensions
were linearly related to BSA. Their data validated the practice of
indexing valve area for BSA and for BSA values which ranged from
0.08–2.1m2, the aortic valve diameter was 0.3-2.2 cm and pulmonary
valve diameter was 0.4–2.8cm. Indexed mean aortic valve area was
1.33 cm2/m2 and pulmonary valve area was 1.7 cm2/m2 .Similarly,
Capps S B et al., [4] showed that the valve diameter directly and
significantly correlated with the BSA. King DH [8] showed that best
predictor of annular diameter was a logartihmic function of BSA.
In the present study, the statistical correlation between BSA and
AV diameter was very significant, as can be seen in [Table/Fig-4].
Hence, BSA alone has an excellent correlation with aortic valve
dimension area and it is a strong predictor of the aortic valves, as for
all other valves. This also proves that the calculation of AV diameter,
as against the BSA of the individual, is a reliable method.
According to Pibarot P*, a patient–prosthesis mismatch (PPM) is
present when the effective orifice area (EOA) of the inserted prosthetic
valve is too small with respect to BSA. (*www.cardiologyonline.com/
wchd05/abstracts/3043%20Pibarot.doc) PPM is defined as an EOA
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Hannah Sugirthabai Rajila Rajendran et al., Aortic annulus in Indians
BSA
AV
BSA
AV
Pearson Correlation
1
.842**
Sig. (2-tailed)
–
.000
N
406
406
Pearson Correlation
.842
1
Sig. (2-tailed)
.000
–
N
406
406
www.jcdr.net
Comparison of these sizes with the manufacturer’s calculated area
for current prosthesis shows that most of the mechanical valves
and bioprostheses are potentially restrictive at rest. Tirone E and
David MD [16] pointed that small prosthetic aortic valves should
be avoided in larger and physically active patients, to reduce the
operative risk and to optimise functional recovery and therefore,
to prevent a patient prosthesis mismatch. Claudia Blais, Jean G
Dumensil and Richard Baillot [17], stressed that a patient prosthesis
mismatch was a strong and an independent predictor of short term
mortality among patients who underwent aortic valve replacements
and that its impact was related both to its degree of severity and the
status of left ventricular function.
[Table/Fig-4]: Correlations
***Correlation is significant at the 0.01 level.
which is indexed for BSAs of < 0.8-0.9 cm2/m2 in the aortic position
and of < 1.2-1.3 cm2/m2 in the mitral position, where EOA represents
the minimal cross-sectional area of the flow jet downstream of the
aortic valve (Damien Garcia, Lyes Kadem [11]) This is a frequent
problem which is seen in patients who undergo aortic or mitral valve
replacements (20–70% prevalence), and its main haemodynamic
consequence is the generation of high transvalvular gradients
through normally functioning prosthetic valves. The greatest impact
of PPM with regards to mortality, is the early postoperative period,
especially in patients with depressed LV functions.
Shahbudin H Rahimtoola and Edward Murphy [12], in 1969 –1978,
described a condition in which the in vivo prosthetic valve effective
orifice area was smaller than that of the native value. Pibarot P and
Dimensil JH [13], described that a patient prosthetic mismatch could
be present when the effective orifice area of the inserted prosthetic
valve is too small with respect to body size. This discrepancy
between the inserted prosthetic valves and the original AV diameter
is the basic cause of PPM post–operatively. To derive the original
annular diameter (a stenosed lesion does not change the annulus
where the prosthetic valve needs to be attached), the BSA is used
as a predictor. But, the already indexed values of AV diameter, which
are derived for the different BSA ranges, are all available only for the
western population. Marc R Moon et al., [14], demonstrated that
patients with BSA values of greater than 2.1 m2 had a dramatic fall
in survival from 78% to 25% with a patient prosthetic mismatch,
whereas patients with BSA values of less than 1.7m2 did not
experience the same response with a patient prosthetic mismatch.
Westaby S et al., [15] gave the mean circularised orifice area in cm2,
as shown in [Table/Fig-5].
Valve
Male
Female
Aortic
4.81 ± 1.3
3.73 ± 0.98
Pulmonary
4.88 ± 1.25
4.32 ± 1.03
Mitral
8.7 ± 2.08
6.94 ± 1.41
Tricuspid
11.9 ± 2.12
9.33 ± 2.02
Hence, a careful selection of bioprosthetic valves with an adequate
ratio of effective orifice area to BSA should be ensured. The prosthetic
valve sizes which are available are made to the standard values. But
there are racial differences to the annular dimensions when they
calculated against the BSA. Hence, a study was undertaken in the
Indian population. The values of aortic valve dimensions as against
the western standards, have been documented in [Table/Fig-3]. In the
present study, it was found that there is a very significant difference
between Indian and western population in the aortic dimensions, as
can be seen in [Table/Fig-6], for BSA values which ranged between
0.61-0.7, 1.11-1.2, 1.21-1.3, 1.51-1.6, 1.61-1.7,1.71-1.8 and 1.81.9 m2. The test of significance was done, which compared the
Indian and standard values, as can be seen in [Table/Fig-7] and
the difference in values was found to be highly significant. In the
range of 1.21-1.3 m2 alone, the diameter was larger than standard,
whereas in all the other ranges which have been mentioned above,
the diameter was smaller than standard values significantly [Table/
Fig-7]. When a patient is taken for surgery, the annular dimensions
are checked against the patient’s BSA. Thus, this study showed
that the normal diameter of aortic valve annulus in Indian population
[Table/Fig-7]: Comparison of Aortic Valve in Indian & Western
Population
[Table/Fig-5]: Mean Circularised Orifice Area in Cm2
BSA
Mean
Std. Deviation
Std. Error Mean
Standard Value
t
df
Sig.
0.61-0.7
12.2000
.41039
.09177
13.5
-14.166
19
.000
0.71-0.8
14.1000
1.77408
.39670
14.1
.000
19
1.000
0.81-0.9
14.4550
1.46664
.32795
14.6
-.442
19
.663
0.91-1.0
15.5650
1.18022
.26391
15.6
-.133
19
.896
1.01-1.1
16.0733
1.34773
.34798
16.3
-.651
14
.525
1.11-1.2
16.6200
.48433
.12505
17.2
-4.638
14
.000
1.21-1.3
18.0714
1.63069
.27564
17.1
3.524
34
.001
1.31-1.4
18.4545
2.66540
.35940
18.7
-.683
54
.498
1.41-1.5
18.8000
1.27879
.21615
19.1
-1.388
34
.174
1.51-1.6
19.6935
1.47758
.18765
20.7
-5.363
61
.000
1.61-1.7
19.8194
.81061
.09553
20.8
-10.264
71
.000
1.71-1.8
20.8095
.87287
.19048
21.5
-3.625
20
.002
1.81-1.9
21.1875
.91059
.22765
22.3
-4.887
15
.000
[Table/Fig-6]: Statistics and One Sample t-test
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Journal of Clinical and Diagnostic Research. 2013 Sept, Vol-7(9): 1842-1845
www.jcdr.net
was definitely lower than the standard values in certain ranges of
BSA and it also proved that the BSA was an excellent predictor of
aortic valve dimension, as there was a linear increase in AV diameter
with BSA.
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PARTICULARS OF CONTRIBUTORS:
1. Associate Professor, Department of Anatomy, Chettinad Hospital and Research Institute, Kelambakkam,Chennai, TamilNadu,India.
2. Director, Institute of Anatomy, Madras Medical College, Chennai, Tamil Nadu, India.
3. Assistant Professor, Department of Cardiology, Stanley Medical College,Chennai, TamilNadu,India-600001.
4. Assistant Professor, Department of Radiodiagnosis, Stanley Medical College, Chennai, TamilNadu, India-600001.
NAME, ADDRESS, E-MAIL ID OF THE CORRESPONDING AUTHOR:
Dr. Hannah Sugirthabai Rajila Rajendran,
7D, KG Towers, 30 & 30A, Bypass Road, Velachery, Chennai -600042
Phone: 9710403803, E-mail: ashrajsanada@gmail.com
FINANCIAL OR OTHER COMPETING INTERESTS: None.
Journal of Clinical and Diagnostic Research. 2013 Sept, Vol-7(9): 1842-1845
Date of Submission: Feb 01, 2013
Date of Peer Review: Mar 19, 2013
Date of Acceptance: Jul 02, 2013
Date of Publishing: Sept 10, 2013
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