THERAPY AND PREVENTION
VALVULAR HEART DISEASE
Mechanisms of increase in mitral valve area and
influence of anatomic features in double-balloon,
catheter balloon valvuloplasty in adults with
rheumatic mitral stenosis: a Doppler and twodimensional echocardiographic study
CHERYL L. REID, M.D., CHARLES R. MCKAY, M.D., P. A. N. CHANDRARATNA, M.D.,
DAVID T. KAWANISHI, M.D., AND SHAHBUDIN H. RAHIMTOOLA, M.B., F.R.C.P.
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ABSTRACT To study the mechanism of increase in the mitral valve area (MVA) and the anatomic
features of the mitral valve that may affect the results of catheter double-balloon valvuloplasty (CBV)
in adult patients with mitral stenosis, Doppler and two-dimensional echocardiography was performed
in 12 patients before and immediately after CBV. Immediately after CBV, there was an increase in
the transverse diameter of the mitral valve orifice from 18 + 1.6 to 25 + 2.8 mm (mean -+ SD, p
20 degrees (p < .05)
< .001). The anterior angles at the commissure increased from 33 ± 6 to 57
and the posterior angles from 36 9 to 54 + 14 degrees (p < .05). The MVA was greater after CBV
in patients with pliable mitral valves (2.6 0.7 cm2) compared with those with rigid mitral valves
(1.9 ± 0.8 cm2; p = .08). After CBV, MVA was smaller in patients with calcification (2.1 ± 0.2
cm2) compared with those without (2.7 0.5 cm2; p - 10) and in those with subvalvular disease
(2.0 ± 0.6 cm2) compared with those without (2.9 ± 0.9 cm2; p = .03). The MVA by Doppler
ultrasound before CBV (1.0 0.2 cm2) correlated well with MVA by cardiac catheterization (1.0 ±
0.3 cm2; r = .8, SEE = 0.2 cm2). After CBV, the correlation of MVA by Doppler ultrasound (2.0
+ 0.5 cm2) with MVA by cardiac catheterization (2.4
0.8 cm2) was poor (r
.3, SEE 0.44
cm2). Doppler studies showed that new mitral regurgitation was produced in four patients (mild in three
and moderate in one) and an increase of mitral regurgitation was produced in one patient. We conclude
that (1) the increase in MVA by double-balloon CBV occurred along the natural planes of the
commissures resulting in increased commissural angle opening; (2) severe calcification of the commissures with rigid valve leaflets was associated with the least increase in mitral valve area after CBV;
calcification of the commissures, rigid valve leaflets, and subvalvular disease were associated with
smaller increases in MVA, (3) new or an increase in mitral regurgitation occurred in over a third of
the patients by Doppler, but in most patients the change was small, and (4) Doppler ultrasound provided
a reasonable estimate of MVA before CBV but was of limited value in the estimation of the MVA
immediately after CBV.
Circulation 76, No. 3, 628-636, 1987.
±
±
±
.
±
±
CLOSED OR OPEN mitral commissurotomy and
valve replacement have been the preferred methods of
treatment for most patients with severe rheumatic
mitral stenosis. 1-5 Recently, catheter balloon valvuloplasty (CBV) with percutaneous single-balloon cathFrom the Section of Cardiology, Department of Medicine, LAC-USC
Medical Center. University of Southern California School of Medicine,
Los Angeles.
Address for correspondence: Cheryl L. Reid, M.D., LAC-USC Medical Center, Section of Cardiology, 2025 Zonal Ave., Los Angeles. CA
90033.
Received Jan. 12, 1987; revision accepted June 11, 1987.
Presented in part at the Annual Scientific Sessions of the American
College of Cardiology. New Orleans, March 1987.
628
=
=
eters has been performed in patients with rheumatic
mitral stenosis .6-I CBV with a double-balloon technique has been shown to be more effective in dilatation
of stenotic rheumatic mitral valves in adult
patients.'2 13 The purposes of this study were to determine by two-dimensional and Doppler echocardiography (1) the mechanism by which the mitral valve area
(MVA) is increased, (2) whether anatomic features of
the mitral valve and subvalvular apparatus influence the
results of CBV, (3) whether mitral regurgitation is
produced or increased, and (4) whether the Doppler
technique can accurately estimate change of MVA
immediately after CBV.
CIRCULATION
THERAPY AND PREVENTION-VALVULAR HEART DISEASE
FIGURE 1. Method of measurement of the morphologic changes induced by double-balloon CBV illustrated in the twodimensional echocardiographic parasternal short-axis view. A, The transverse diameter (TD) is measured between the anterior
(A) and posterior (P) commissures during the maximal opening of the mitral valve orifice (MVO) in early diastole. B, The angle
of the commissural opening is measured between two tangential lines drawn from the point of each commissure to the anterior
and posterior leaflets of the mitral valve.
Methods
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Patients. The study consisted of the first 12 patients with
symptomatic mitral stenosis who underwent CBV by the doubleballoon technique. Informed consent was obtained from all
patients. There were 11 women and one man who ranged in age
from 25 to 70 years (mean 43 ± 15). Two patients were in
NYHA functional class 1I, eight in class Ill, and two in class IV.
Three patients had undergone a previous mitral commissurotomy. Three patients were in atrial fibrillation. Patients with
echocardiographic evidence of left atrial thrombus were considered not suitable for CBV. Initially patients with pulmonary
edema, high pulmonary artery pressures near systemic arterial
pressure and low cardiac output, and right heart failure were also
excluded. Patients with evidence of other severe valve disease
requiring surgery or mild mitral stenosis by cardiac catheterization were excluded.
Two-dimensional echocardiography. All patients had a
two-dimensional (2D) echocardiogram on the day before cardiac
catheterization. After CBV, 2D echocardiographic studies were
performed the day after the procedure in 1 1 patients and at 1
month after CBV in one patient. One patient did not have an
initial study because of equipment malfunction and was
excluded from analysis. In two patients, the mitral valve was
A
heavily calcified and the orifice could not be visualized for
measurement of morphologic changes. These patients were
included for analysis of anatomic features only. An Irex Meridian Echocardiographic Doppler System was used to record the
images on videotape for playback analysis. The smallest orifice
of the mitral valve was located in the parasternal short-axis view
by scanning from the level of the left atrium to the left ventricle.
The gain settings were adjusted to obtain the maximum visualization of the entire circumference of the mitral valve orifice.
Assessment ofmorphologic changes. The transverse diameter
of the mitral valve orifice during maximal valve opening in early
diastole was measured between the anterior and posterior commissures. The opening angle at the two commissures was
assessed by drawing a tangential line from the point of the
commissure to the maximal opening of the anterior and posterior
leaflet of the mitral valve (figures 1 and 2). A mean of three
measurements was used in patients in sinus rhythm and five to
10 measurements in patients with atrial fibrillation.
Since there is no standard for evaluating changes in transverse
diameter or commissural angle after CBV, the changes were
assessed by the extent to which these variables approached
normal values. Therefore, 2D echocardiograms of 10 normal
men and 10 normal women were analyzed. These 20 patients
B
FIGURE 2. Two-dimensional echocardiogram in the parasternal short-axis view at the level of the mitral valve during early
diastole in patient 2. A. Before double-balloon CB V the transverse diameter was 20 mm and the angles of the anterior and posterior
commissure were 30 and 32 degrees, respectively. Calcification of the posterior commissure was present. B, After CBV the
transverse diameter increased to 27 mm and the opening angles increased 93% and 13% for the anterior and posterior commissure,
respectively. The increase in transverse diameter associated with an increase of the anterior angle of opening suggests that the
split occurred to a greater extent at the anterior commissure.
Vol 76, No. 3, September 1987
629
REID et al.
were selected on the basis of a negative history of cardiac disease
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and normal cardiac examination (15 patients) or a diagnostic
cardiac catheterization and angiography that did not show any
mitral valve abnormality (five patients). Patients with any evidence of valvular, myocardial, coronary artery, or any other
cardiac disease were excluded from the normal group.
Anatomic features of the mitral valve and subvalvular apparatus before CBV. The severity of calcification at each commissure was assessed as mild, moderate, or severe. The mitral
valve was judged pliable if the body of the leaflets was free of
calcium and had a wide excursion during diastole. Subvalvular
involvement was evaluated by noting the presence of calcification and thickening when compared with the surrounding
endocardium.
Measurements of MVA. The MVA was obtained from a
freeze-frame analysis of the maximal mitral valve opening in
early diastole. The mitral valve orifice was planimetered directly
from the video screen with a light-pen system; the area in square
centimeters was assumed to be the effective MVA. Measurements were made in all patients both before and after CBV. A
mean of three measurements was obtained in patients in sinus
rhythm and five to 10 measurements in patients with atrial
fibrillation.
Doppler ultrasound
MVA. Doppler echocardiograms were obtained successfully
in all 12 patients. Recordings were made with an Irex Meridian
Echocardiographic Doppler System with the use of both imaging
and nonimaging transducers at a frequency of 2.0 MHz. Continuous-wave Doppler ultrasound recordings were made from
the apical four-chamber view while the transducer was angled
with the use of visual and auditory monitoring to obtain the
maximal velocity across the mitral valve. No correction was
made for the angle between the Doppler signal and transmitral
blood flow. A hardcopy recording was made at 75 mm/sec, and
the MVA was calculated from the Doppler recordings by the
pressure half-time method. 14 A mean of three measurements was
obtained for patients in sinus rhythm and a mean of five to 10
measurements for patients in atrial fibrillation. Pre-CBV studies
were obtained on the day before CBV in seven patients. PostCBV recordings were made at 1 day in four patients and l week
in one patient. Simultaneous Doppler recordings and hemodynamic measurements were made during cardiac catheterization
before CBV in five patients and simultaneously after CBV in
seven
patients.
Assessment of mitral regurgitation. The presence and severity
of mitral regurgitation was assessed by pulsed Doppler examination. The severity of the mitral regurgitation was graded from
0 to 4 + based on the extent to which the regurgitant jet could
be recorded within the left atrium.'5 In addition, regurgitation
detected only immediately above the value leaflets was graded
as trace mitral regurgitation to distinguish it from more significant 1 + mitral regurgitation. The Doppler ultrasound assessment of mitral regurgitation was made 1 day before CBV in all
patients. After CBV, assessment of the mitral regurgitation was
made at 1 day in 1 1 patients and at 1 week in one patient.
Cardiac catheterization and CBV. All patients had complete diagnostic right and left heart catheterization and angiography before CBV. At CBV, right and left heart pressures, blood
oxygen saturations, cardiac output, and left atrial and left ventricular angiograms were obtained both before and after CBV.
Mitral valve area was calculated by standard formulas16 from the
simultaneous left atrial and left ventricular pressures recorded at
15 cm/sec paper speed and the thermodilution cardiac output. No
correction was made for the presence of mitral regurgitation in
the calculation of the MVA.
The double-balloon technique of CBV for mitral stenosis has
been previously described. 12 13 Briefly, the technique consists
630
of two separate transseptal catheters placed across the interatrial
septum. The mitral valve dilatation catheters were then inserted
over exchange guidewires and positioned side by side across the
stenotic mitral valve. The balloons were then inflated simultaneously while aortic pressure and pulmonary arterial wedge
pressures were monitored continuously. After CBV, the patient
was monitored overnight in the intensive cardiac care unit. The
patient was ambulatory the next day and was discharged from
the hospital 2 days after the procedure.
Data analysis. 2D and Doppler echocardiographic recordings
were analyzed by an experienced echocardiographer who was
blinded to the results of the cardiac catheterization. A second
echocardiographer evaluated the anatomic features of the mitral
valve and subvalvular apparatus before CBV and was blinded
to both the results of the cardiac catheterization and measurement of the morphologic changes. The relationship between
Doppler and 2D echocardiographic and cardiac catheterization
estimates of the MVA were compared by linear regression
analysis. A paired t test was used to compare the pre- and
post-CBV measurement of the transverse diameter and the
angles at the commissures of the mitral valve orifice. Data are
expressed as mean + SD.
Results
Hemodynamic results. Immediate reductions in the
severity of the mitral stenosis were achieved in all 12
patients (table 1). There was an increase in mean MVA
from 1.0 ± 0.3 cm2 before CBV to 2.4 + 0.8 cm2 after
CBV (p < .001). Mitral regurgitation by angiography
before CBV was graded as absent in four patients, 1 +
in seven patients, and 2 + in one patient. After CBV,
repeat left ventricular angiography showed no new
mitral regurgitation or increase in the severity of preexisting mitral regurgitation in any patient.
Two-dimensional echocardiography.
Measurements of mitral valve orifice in normal subjects. In
the group of normal subjects the mean transverse diameter of the mitral valve orifice was 26 ± 2.3 mm (range
24 to 30) for women and 29 ± 2.6 mm (range 26 to
34) for men (p = .03, figure 3). The angle of anterior
commissural opening was 90 + 7 degrees (range 83 to
100) for men and 91 ± 6 degrees (range 79 to 97) for
women (p - NS); the angle at the posterior commissural opening was 93 ± 3 degrees (range 86 to 96) for
men and 92 ± 6 degrees (range 84 to 101) for women
(p = NS, figure 3).
Morphologic changes after CBV. Tears of the valve leaflets or rupture of the chordae of the mitral valve were
not visualized in any patient. The mean transverse
diameter of the mitral valve orifice increased from 18
± 1.6 mm before CBV to 25 ± 2.8 mm after CBV
(p < .001) (figure 3). The mean increase for the group
was 38 ± 17% (table 2). All patients in whom 2D
echocardiograms could be obtained were women; there
was no significant difference (p = .3) between the
measurement of the transverse diameter after CBV in
CIRCULATION
THERAPY AND PREVENTION-VALVULAR HEART DISEASE
TABLE 1
figure 3). The mean increase at the anterior commissure
Cardiac catheterization, Doppler, and two-dimensional echocardiographic results in 12 patients undergoing mitral valve CBV
was 71 +- 48% and that at the posterior commissure was
47 ± 23%. The angle of commissural opening after
Patient
Pre-CBV
Post-CBV
2.
Pre-CBV
Post-CBV
3.
Cardiac cath.
HR MVA MR
80
0.6
0
Doppler
HR MVA MR
80
0.5
2DE
MVA
In two patients (Nos. 8 and 9), heavy
calcification precluded visualization of the mitral valve
77 1.3 1+
79 2.2 1 +
89 1.1
70 1.6
Tr
Tr
1.1
2.0
75 1.3 1+
-
orifice for measurements. In these patients, the calcification was severe in one commissure and was associated with mild calcification of the subvalvular apparatus and rigid valve leaflets; these patients had the
smallest MVAs after CBV, 1. 1 and 1.7 cm2. In three
patients (Nos. 1, 2, and 4), there was mild calcification
of one of the commissures with or without associated
subvalvular disease; in two of these patients, the calcification was associated with failure to increase the
respective angle of commissural opening (patients 2
and 4). Calcification of both commissures present in
two patients (Nos. 5 and 12) was associated with only
a small 3 mm increase in the transverse diameter.
The presence of calcification resulted in a mean
MVAof21 ± 02cm2comparedwith2.7 ± 0.5cm2
106
3.6
1+
104
2.4
1+
4
84 1.1 0
93 2.2 0
81 0.9 1 +
100 1.7 1 +
0.9
1.6
Pre-CBV
108 1.1 1+
58 0.9 1+
0.9
Post-CBV
108 2.9
80
1+
1.7
78 0.8 1 +
72 2.9 1 +
63 0.9 1 +
81 2.4 1 +
1.2
2.2
96 0.8 1+
96 1.9 1+
74 0.9 0
98 2.4 1+
0.9
2.3
71 0.6 1+
98 1.1 1 +
73 1.0 1 +
98 1.6 1 +
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1+
1.5
6.
Pre-CBV
Post-CBV
7.
Pre-CBV
Post-CBV
Pre-CBV
Post-CBV
9.
Pre-CBV
Post-CBV
subvalvular appa-
0.8
2.0
102 1.6 1+
5.
Anatomic features of the mitral valve and
0
67 1.7 01
Post-CBV
Pre-CBV
this group of patients was significantly smaller (p <
.001) than the corresponding values in normal women.
90 2.9 0
Pre-CBV
Post-CBV
CBV at both the anterior and posterior commissures in
ratus (table 3).
-(p = .10) in patients without calcification. Those
patients with pliable leaflets had a greater mean MVA
after CBV (2.6 + 0.7 cm2) compared with those with
66 0.6 2+
69 0.7 Tr
rigid mitral valves (1.9 ± 0.8 cm2; p = .08). The
74 1.7 2+
77 1.6 1+
presence of subvalvular disease was also associated
with a smaller MVA after CBV (mean 2.0 ± 0.6 cm2)
7 1.1 00. 77 1.1 0
Pre-CBV
74
1.3
Post-CBV
97 3.6 0
101 2.7 2 +
3.0
than in patients
without subvalvular disease (mean 2.9
ii.
±0.9 cm2; p = .03) (figure 4).
Pre-CBV
96 1.0 1+
96 1.2 1+
1.3
MVA. The 2D echocardiographic estimates of the
Post-CBV
105 2.1 1 +
118 2.7 1 +
2.1
MVA in the nine patients in whom it could be measured
73 1.1 0
79 12 0
13
12.
was 1.1 ± 0.2 cm2 before CBV (range 0.8 to 1.3 cm2)
Post-CBV
731 20 0
77 2.5 Tr
and 2.2 ± 0.4 cm2 after CBV (range 1.6 to 3.0 cm2).
2.5
Mean pre-CBV 86 1.0
76 1.0
The correlation of 2D echocardiographic estimates of
1.0
+SD
14 0.3
10 0.2
0.2
MVA before and after CBV with those obtained by
Mean post-CBV 92 2.4
89 2.0
cardiac catheterization was poor (r = .4 and r .4).
2.2
+SD
12 0.8
16 0.5
0.4
Throughout the entire range of MVAs observed, i.e.,
HR = heart rate (beats/min); MR = mitral regurgitation (0 to 4 +);
both before and after CBV, the correlation was good
MVA = mitral valve area
(cm2); Tr trace; 2DE = two-dimensional
echocardiography.
this group of patients (25 ± 2.8 mm) and normal
women (26 ± 2.3 mm).
In all patients the angle of commissural opening
increased at one or both commissures. The anterior
commissure increased from 33 + 6 degrees before
CBV to 57 ± 20 degrees after CBV (p < .05) and the
posterior commissure increased from 36 ± 9 degrees
before CBV to 54 + 14 degrees after CBV (p < .05,
Vol. 76, No. 3,
September 1987
(r
= .8, SEE = 0.3 cm 2).
Doppler ultrasound (table 1)
MVA. The MVA calculated from the Doppler velocity
recordings before CBV in all 12 patients was 1.0 ± 0.2
cm2 (range 0.5 to 1.3 cm2). After CBV the mean MVA
increased significantly to 2.0 ± 0.5 cm2 (p < .001);
range 1.5 to 2.6 cm2. The correlation of the Doppler
ultrasound estimates of the MVA with that obtained by
cardiac catheterization before CBV was r = .8 (SEE
0.2 cm2, figure 5). After CBV the correlation between
the two techniques was poor (r = .3, SEE = 0.44
631
REID et al.
p <. 00i
p = NS
A.
B.
p <.001
p <.001
C.
p<.OOl
p <.001
r-
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NS
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Male Female
Past
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CB 3V
NORMALS
I
I
!
Male Female
CBV
MITRAL
STENOSIS
NORMALS
Pre
Male Female
Past
CBV
CBV
MITRAL
STENOSIS
NORMALS
Pre
Post
CBV
CBV
MITRAL
STENOSIS
FIGURE 3. Comparison of transverse diameter and angles of commissural opening before and after CBV in nine patients with
mitral stenosis with 10 normal women and 1 0 normal men. A, The mean transverse diameter was significantly different between
normal women and normal men (p = .03). Before CBV, the transverse diameter was significantly smaller in the patients compared
with the normal women. After CBV there was no significant difference between the patients and normal women. Although the
anterior angle (B) and posterior angle (C) of commissural opening increased after CBV, both were significantly smaller than
those of normal women.
cm2). The correlation of all MVAs (before and after
CBV) by Doppler with those obtained by cardiac
catheterization was good (r = .8, SEE = 0.4 cm2,
figure 5).
Mitral
regurgitation (figure 6). Before CBV,
no
mitral
regurgitation was detected in four patients, trace mitral
regurgitation was found in two patients, and 1 + mitral
regurgitation in six patients. Doppler ultrasound failed
to identify the presence of mitral regurgitation dem-
onstrated by angiography in one patient before CBV.
After CBV, Doppler ultrasound detected no change
in the presence or severity of mitral regurgitation in
seven patients. The presence and severity of the mitral
regurgitation by Doppler ultrasound increased from
absent to trace in one patient, absent to 1 + mitral
regurgitation in two patients, and trace to 1 + mitral
TABLE 2
Morphologic changes in mitral valve orifice by CBV
Angle of commissure (degrees)
Transverse diameter (mm)
Patient
Pre
Post
1
20
20
17
19
18
15
17
19
18
18
1.6
28
27
24
22
26
23
29
24
2
4
5
6
7
10
11
12
Mean
+SD
21
25A
2.8
Change
(%)
+ 40
+ 35
+41
+ 16
+ 44
+ 53
+71
+ 26
+ 17
+ 38
+ 17
Anterior
Posterior
Change
Pre
Post
28
30
27
25
33
42
39
36
37
33
6
54
58
29
43
42
63
51
74
97
57B
20
(%)
Pre
Post
+ 93
+ 93
31
32
26
26
46
44
48
27
40
36
53
36
47
44
60
57
64
39
82
54B
14
+7
+ 72
+ 27
+ 50
+31
+ 106
+ 162
+ 71
+48
9
Change
(%)
+ 71
+ 13
+81
+ 69
+ 30
+ 30
+33
+ 44
+51
+ 47
+23
Ap <.001 post- vs pre-CBV; Bp <.05 post- vs pre-CBV.
632
CIRCULATION
THERAPY AND PREVENTION-VALVULAR HEART DISEASE
TABLE 3
Anatomic features of the mitral valve and subvalvular apparatus
before CBV
Commissures
Patient
Anterior
I
2
4
5
6
7
8
9
10
11
12
Mild Ca+ +
Mild Ca+ +
Mild Ca+ +
-
Severe Ca +
Posterior
Subvalvular
apparatus
Pliable
Mild Ca+ +
Mild Ca+ +
Severe Ca+ +
Mild Ca++
Valve
leaflet
mobility
Mild Ca+ +
Pliable
Pliable
Rigid
Pliable
Pliable
Rigid
Rigid
Pliable
Pliable
Rigid
Thickened
Mild Ca+ +
Thickened
Mild Ca +
Mild Ca ++
Thickened
Thickened
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Ca + + = calcification.
regurgitation in one patient; in one patient new 2+
mitral regurgitation was detected.
Discussion
The technique of CBV in patients with mitral stenosis was first described by Inoue et al.6 using a single
balloon and by Al Zaibag et al.12 using the doubleballoon technique. Initial results with the new doubleballoon technique appear encouraging.12' 13 Inoue et
al. showed, that the mechanism by which the singleballoon technique works is splitting of commissures.
The mechanism by which double-balloon CBV produces the increase in mitral valve area has not been
reported. After CBV, the increase in MVA may result
from (1) splitting of the commissures, (2) stretching of
the valve leaflets and subvalvular apparatus, and/or (3)
tears or fractures of the valve leaflets. The latter has
been described in patients undergoing CBV for aortic
N
4-
E
CALCIFICATION
VALVE
MOBILITY
SUBVALVULAR
DI SEASE
1
O3.c
m._
'U
I-2
2
O-
U t0
Absent Present
Plioble
Rigid
Absent Present
FIGURE 4. The anatomic features of the mitral valve in relationship
to the resultant mean MVA immediately after CBV are shown for the
presence or absence of calcification, subvalvular disease, and pliable or
rigid mitral valves in 11 patients. The mean MVA was greater in these
groups with pliable mitral valves without calcification or subvalvular
disease.
Vol. 76, No. 3, September 1987
stenosis.'7 Each of these potential mechanisms has
different applications for immediate results and longterm success of the procedure.
Pathologic studies have shown that rheumatic mitral
stenosis results from (1) fusion and shortening of the
chordae, (2) rigidity and thickening of the valve leaflets, (3) fusion of the commissures, and (4) combinations of these abnormalities.'8-20 The commissural
fusion, however, is the most important component in
76% of the cases.18 Results with surgical, open or
closed, mitral commissurotomy indicate that excellent
long-term results will occur if the commissures are
appropriately incised2' 5, 21, 22 but that the results are
less satisfactory in the presence of rigid and calcified
valves.23 Inoue performed single-balloon CBV of the
mitral valve in the operating room during open mitral
commissurotomy in six patients and found that at least
one commissure was adequately separated in all
patients.6 The results of our study show that the
increase in MVA occurring after double-balloon CBV
is also caused by a split along the natural planes of one
or both commissures. Before CBV the mean transverse
diameter in our patients was 18 ± 1.6 mm; it is of
interest that this finding is similar to the intercommissural diameter of 19 mm measured at autopsy in
patients with mitral stenosis. 18 Moreover, the values of
the transverse diameter after CBV corresponded to
autopsy measurements in normal subjects.24 After
CBV there was no significant difference in the transverse diameter measurement in our patients (25 ± 2.8
mm) and those we measured in normal women (26 +
2.3 mm); all but one of our patients were women. One
would expect, however, that post-CBV transverse
diameters might be larger in men.
If stretching of the mitral valve leaflets or subvalvular apparatus rather than commissural splitting was
the major mechanism by which the MVA increased
after CBV, then the increase in transverse diameter
would be small and only the angles of commissural
opening would be expected to increase. In two of our
patients (Nos. 5 and 12), the increase in transverse
diameter was modest, although both angles of commissural opening increased. Failure to increase the
transverse diameter in these patients was associated
with calcification of both commissures and may represent an inability to split the commissures because of
the calcifications and a component of stretching; this
finding is compatible with those seen at surgery.23
Longer follow-up of these patients will be required to
determine whether this degree of increase in transverse
diameter is sufficient to sustain good long-term results.
Analysis of data from surgical mitral commissurot633
REID et al.
lA~
PRE- CBV
4 -
4
POST-CBV
j
E
E
E
3
3
<r
0
0
0
E2 -/
2
cl:
ALL PRE- AND
POST- CBV
4
2
2
2
08
cr
0
uJ
0L~1
rO-
O
y
D
*
0
C-J
LLI
.8
=.65x + .32
SEE
-
0.15
1
2
3
CATH MVA (cm2)
=
0
4
0
a-
0.3
y= .19x + 1.6
0
SEE = 0.44
0
1
2
3
CATH MVA (cm2)
4
- ,< ,~~r=
y
0.8
=.54x + .56
SEE
0
0.4
2
3
1
CATH MVA (cm2)
4
FIGURE 5. Linear regression analysis of MVA measured by Doppler ultrasound compared with that measured by cardiac
catheterization before (A) and after CBV (B). The Doppler-derived MVA before CBV showed a good correlation (r .8) with
catheterization-derived MVA but after CBV the correlation was poor (r = .3). With all pre- and post-CBV values considered
together (C), the correlation between Doppler and cardiac catheterization was good (r
.8).
=
=
omy has
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shown that 70% of patients will maintain good
results after 5 years of follow-up if one commissure is
successfully opened and 89% if both commissures are
opened.25 The changes in the angles of opening at the
commissures after CBV may also be used to assess
splitting at the associated commissure. In all our
patients, the opening angle between the commissures
showed an increase in one or both angles. In two
patients (Nos. 2 and 4) only one angle of commissural
opening showed an increase. Since the transverse diameter increased, we interpret this increase to have
resulted from a split only at the commissure with the
increase in the angle of opening. Failure to increase an
opening angle at a commissure or a change in opening
of only a few degrees associated with an increase in
transverse diameter in these patients was related to
calcification at the unsplit commissures. An increase in
transverse diameter accompanied by an increase of both
angles at the commissures suggests that both commissures were split, and this occurred in patients without
commissural calcium. Although the angles of commissural opening at both the anterior and posterior
commissures showed a significant mean increase after
CBV, they were still significantly less than the opening
angles obtained in normal subjects. The presence of
rigid mitral valve leaflets or subvalvular disease in
addition to failure to split the commissure may also
contribute to the failure of the angles of opening to
approach normal values.
Although the presence of rigid, calcified valves and
subvalvular disease was associated with a smaller
MVA after CBV than in those patients without these
anatomic findings, it did not preclude a satisfactory
result. One of the potential disadvantages of CBV is
that the fusion of the chordae tendineae may not be
relieved. However, chordal fusion as the dominant
cause of mitral stenosis is present in only a minority of
634
patients (9%). 18 Our initial results show findings that
are comparable to those obtained with open or closed
mitral commissurotomy in which the subvalvular apparatus was assessed directly and fusion relieved.26 Al
Zaibag et al. 12 noted splitting of the subvalvular mitral
apparatus in one of two patients in whom they performed double-balloon CBV under direct vision during
open mitral commissurotomy. Therefore, even when it
is difficult to visualize the subvalvular apparatus
directly by 2D echocardiography, the precise quantification of the morphologic changes produced by CBV
in the manner we have described may provide evidence
of the contribution of subvalvular disease to early and
possibly late results.
The production of significant mitral regurgitation
after surgical commissurotomy is associated with a
poor prognosis.525. 27, 28 Significant mitral regurgitation during open or closed mitral commissurotomy
may be produced if a tear or incision is made into the
anterior or posterior leaflet of the mitral valve or if the
chordae tendineae are ruptured.'9' 29 Less severe
degrees of mitral regurgitation may occur because the
rigid valve leaflets and shortened chordae tendineae
prevent complete closure of the leaflets after incision
of the commissures or because of small tears in the
valve leaflets. Although in our group of patients new
or an increase in mitral regurgitation by Doppler ultrasound was detected in five patients after CBV, in only
one patient was it considered to be moderate (2 + ). This
differed from the findings by angiography in these
patients. Angiography may fail to detect small amounts
of mitral regurgitation and to distinguish qualitatively
small changes in its severity, such as from trace to 1 +
mitral regurgitation. Moreover, angiography may be
interpreted as showing trace to 1 + regurgitation caused
by an arrhythmia if the electrocardiogram is not simultaneously monitored; in our laboratory, the electrocarCIRCULATION
THERAPY AND PREVENTION-VALVULAR HEART DISEASE
CL
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Q)
IT[
CL
Tr[
0
a
Pre
CBV
Post
CBV
FIGURE 6. Assessment of the presence atid severity of mitral regurgitation by the pulsed Doppler technique in 12 patients before and after
CBV. The 1 + grade of mitral regurgitation is subdivided into trace (Tr)
and 1 + mitral regurgitation. Mild mitral regurgitation was produced in
four patients and increased in one patient. In one patient, new 2 + mitral
regurgitation occurred.
diogram is photographed on the cineangiographic film
and thus this problem is unlikely to occur. On the other
hand, Doppler ultrasound may be overly sensitive and
may detect trace to 1 + mitral regurgitation when there
is none present.30 The regurgitation associated with
mitral stenosis may occur in 'jets" and therefore may
fail to be detected by Doppler ultrasound if a careful
search of the left atrium is not made with the pulsed
Doppler mode.31 This may be the reason why we failed
to detect mitral regurgitation before CBV in one patient
shown to have mitral regurgitation by angiography. In
no patient did we detect the occurrence of a tear of the
valve leaflets or rupture of the chordae tendineae; however, echocardiography may not be sensitive enough to
detect small tears and ruptures. The significance of
small increases in mitral regurgitation detected by Doppler ultrasound after CBV remains to be established.
Vol. 76, No. 3, September 1987
Estimates of MVA by Doppler ultrasound have been
shown to have a good correlation with results obtained
by cardiac catheterization in patients with unoperated
mitral stenosis (r = .85) as well as those who have
undergone mitral commissurotomy (r = .90).32 The
results of our study confirm that Doppler ultrasound
shows a good correlation with cardiac catheterization
for the MVA before CBV (r = .8, SEE = 0.15 cm2).
After CBV, however, the results of the Doppler studies
did not accurately reflect the changes in the MVA by
cardiac catheterization (r = .3, SEE = 0.44 cm2), a
finding not previously reported. The MVA by cardiac
catheterization was not corrected for the presence of
mitral regurgitation. However, if the mitral regurgitant
flow had been considered, the calculated MVA would
have been larger and thus the discrepancy between the
mean MVA by cardiac catheterization (2.5 ± 0.8 cm2)
and the mean MVA by Doppler (2.0 ± 0.5 cm2) would
have been even greater. The poor correlation between
the Doppler estimate of the MVA and that obtained by
cardiac catheterization after CBV may be related to
several factors such as small left-to-right shunts not
detected by oximetry or to inherent problems with the
Doppler pressure half-time method. The data in this
series were inconclusive in this regard. At this time,
caution should be exercised in using the Doppler estimate of the MVA to assess the results immediately after
CBV.
The results of this study show that the mechanism by
which the MVA was increased after double-balloon
CBV was a split along one or both commissures. By
2D echocardiography, this was seen as an increase in
the transverse diameter between the commissures and
was associated with an increased opening of the angle
at one or both of the commissures. Severe calcification
of the mitral valve with rigid valve leaflets was associated with the least increase in MVA. Calcification at
both commissures was associated with an incomplete
split of the commissures; calcification of a single commissure was associated with a failure to increase the
angle of opening. These results suggest that better
results with CBV might be expected in a patient with
a pliable valve without evidence of commissural calcium or subvalvular disease, although the presence of
one or more of these anatomic features does not preclude a satisfactory result. Although changes in the
presence or severity of the mitral regurgitation was seen
in five of the 12 patients by Doppler technique, in most
patients the increase in mitral regurgitation was mild.
Although Doppler studies may be performed even
when 2D echocardiograms cannot be obtained, the poor
correlation of the Doppler estimate of the MVA after
635
REID et al.
CBV with that obtained by cardiac catheterization limits its usefulness in the immediate post-CBV evaluation
of these patients.
16.
17.
References
1 Harken DE, Ellis LB, Ware PF, Norman LR: The surgical treatment
of mitral stenosis. 1. Valvuloplasty. N Engl J Med 239: 801, 1948
2. Sellors HT, Bedford DE, Somerville W: Valvotomy in the treatment
of mitral stenosis. Br Med J 2: 1059, 1953
3. Housman LB, Bonchek L, Lambert L, Grunkemeier G, Starr A:
Prognosis of patients after open mitral commissurotomy: actuarial
analysis of late results in 100 patients. J Thorac Cardiovasc Surg
73: 742, 1977
4. John S, Bashi VV, Jairaj PS: Closed mitral valvotomy: early results
and long-term follow-up of 3724 consecutive patients. Circulation
Downloaded from http://circ.ahajournals.org/ by guest on June 18, 2017
68: 891, 1983
5. Gross RI, Cunningham JN, Snively SL, Catinella FP, Nathan IM,
Adams PX, Spencer FC: Long-term results of open radical mitral
commissurotomy: ten year follow-up study of 202 patients. Am J
Cardiol 47: 821. 1981
6. Inoue K, Owaki T, Nakamura T, Kitamura F, Miyamoto N: Clinical
application of transvenous mitral commissurotomy by a new balloon catheter. J Thorac Cardiovasc Surg 87: 394, 1984
7. Kveselis DA, Rocchini AP, Beekman R, Snider AR, Crowley D.
Dick M, Rosenthal A: Balloon angioplasty for congenital and
rheumatic mitral stenosis. Am J Cardiol 57: 348, 1986
8. Lock JE, Khalilullah M, Shrivastava S, Bahl V, Keane JF: Percutaneous catheter commissurotomy in rheumatic mitral stenosis.
N Engl J Med 313: 1515, 1985
9. Babic UU, Pejcic P, Djurisic Z, Vucine M, Grujicic SM: Percutaneous transarterial balloon valvuloplasty for mitral valve stenosis.
Am J Cardiol 57: 1101, 1986
10. McKay RG, Lock JE, Keane JF, Safian RD, Aroesty JM, Grossman
W: Percutaneous mitral valvuloplasty in an adult patient with calcific rheumatic mitral stenosis. J Am Coll Cardiol 7: 1410, 1986
11. Palacios IF, Lock JE, Keane JF, Block PC: Percutaneous transvenous balloon valvotomy in a patient with severe calcific mitral
stenosis. J Am Coll Cardiol 7: 1416, 1986
12. Al Zaibag M, Ribeiro PA, Al Kasab S, Al Fagih MR: Percutaneous
double-balloon mitral valvotomy for rheumatic mitral-valve stenosis. Lancet 1: 757, 1986
13. McKay CR, Kawanishi DT, Rahimtoola SH: Catheter balloon
valvuloplasty (CBV) of the mitral valve in adults using a double
balloon technique: early hemodynamic results. JAMA 257: 1753,
1987
14. Holen J, Landmark K, Simonsen S, Ostrem T: Determination of
effective orifice area in mitral stenosis from noninvasive ultrasound
Doppler data and mitral flow rate. Acta Med Scand 201: 83. 1977
15. Abbasi A, Allen MW, De Cristofaro D, Ungar 1: Detection and
636
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
estimation of the degree of mitral regurgitation by range-gated
pulsed Doppler echocardiography. Circulation 61: 143, 1980
Cohen MV, Gorlin R: Modified orifice equation for the calculation
of mitral valve area. Am Heart J 84: 839, 1972
McKay RG, Safian RD, Lock JE, Mandell VS, Thurer RL, Schmitt
SJ: Balloon dilatation of calcific aortic stenosis in elderly patients:
postmortem, intraoperative, and percutaneous valvuloplasty studies. Circulation 74: 1 19, 1986
Rusted IE, Scheifley CH, Edwards JE: Studies of the mitral valve.
II. Certain anatomic features of the mitral valve and associated
structures in mitral stenosis. Circulation 14: 398. 1956
Brock RC: The surgical and pathological anatomy of the mitral
valve. Br Heart J 14: 489, 1952
Roberts WC: Morphologic features of the normal and abnormal
mitral valve. Am J Cardiol 51: 1005, 1983
Morrow AG, DePlessis LA, Wilcox BR: Hemodynamic studies
after mitral commissurotomy. Surgery 54: 463, 1962
Higgs LM, Glancy DL, O'Brien KP, Epstein SE, Morrow AG:
Mitral restenosis: an uncommon cause of recurrent symptoms following mitral commissurotomy. Am J Cardiol 26: 34, 1970
Hoeksema TD, Wallace RB, Kirklin JW: Closed mitral commissurotomy: recent results in 291 cases. Am J Cardiol 17: 825, 1966
Rusted IE, Scheifley CH, Edwards JE: Studies of the mitral valve.
I. Anatomic features of the normal mitral valve and associated
structures. Circulation 6: 825, 1952
Baker C, Hancock WE: Deterioration after mitral valvotomy. Br
Heart J 22: 281, 1960
Mullin EM, Glancy DL. Higgs LM. Epstein E, Morrow AG:
Current results of operation for mitral stenosis: clinical and hemodynamic assessments in 124 consecutive patients treated by closed
commissurotomy, open commissurotomy. or valve replacement.
Circulation 46: 298, 1972
Ellis LB, Benson H. Harken DE: The effect of age and other factors
on the early and late results following closed mitral valvuloplasty.
Am Heart J 75: 743, 1968
Rutledge R, McIntosh CL, Morrow AG, Picken CA, Siwek LG,
Zwischenberger JB: Mitral valve replacement after closed mitral
commissurotomy. Circulation 66(suppl 1): 1-162, 1982
Rusted IE, Scheifley CH, Edwards JE, Kirklin JW: Guides to the
commissures in operations upon the mitral valve. Proc Mayo Clin
26: 207, 1951
Meltzer RS, Abovich L, Finkelstein M: Regurgitation of all four
cardiac valves detected by Doppler echocardiograph. Am J Cardiol
58: 169, 1986
Patel AK, Rowe GG, Thomsen JH. Dhanani SP, Kosolcharoen P,
Lyle LEW: Detection and estimation of rheumatic mitral regurgitation in the presence of mitral stenosis by pulsed Doppler echocardiography. Am J Cardiol 51: 986, 1983
Smith MD, Handshoe R, Handshoe S. Kwan OL, De Maria AN:
Comparative accuracy of two-dimensional echocardiography and
Doppler pressure half-time methods in assessing severity of mitral
stenosis in patients with and without prior commissurotomy. Circulation 73: 100, 1986
CIRCULATION
Mechanisms of increase in mitral valve area and influence of anatomic features in
double-balloon, catheter balloon valvuloplasty in adults with rheumatic mitral stenosis: a
Doppler and two-dimensional echocardiographic study.
C L Reid, C R McKay, P A Chandraratna, D T Kawanishi and S H Rahimtoola
Downloaded from http://circ.ahajournals.org/ by guest on June 18, 2017
Circulation. 1987;76:628-636
doi: 10.1161/01.CIR.76.3.628
Circulation is published by the American Heart Association, 7272 Greenville Avenue, Dallas, TX 75231
Copyright © 1987 American Heart Association, Inc. All rights reserved.
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