573
Follow-up of Patients Undergoing
Percutaneous Mitral Balloon Valvotomy
Analysis of Factors Determining Restenosis
F. Palacios, MD, Peter C. Block, MD,
Gerard T. Wilkins, MBChB, and Arthur E. Weyman, MD
Igor
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This study reports the clinical follow-up (13±1 months) of 100 consecutive patients who
underwent percutaneous mitral balloon valvotomy (PMV). Echocardiographic (n=32) and
cardiac catheterization (n=37) data from this group are also included. Patients were divided
into two groups by an echocardiographic score. PMV resulted in a good hemodynamic result
(post-PMV mitral valve area, .1.5 cm2) in 88% of patients with a score of 8 or less and 44%
of patients with a score of more than 8. Eighty-eight percent of patients with a score of 8 or less
(n =57) were New York Heart Association (NYHA) functional Classes III and IV before PMV;
at follow-up, 81% were NYHA Class I and 12% were NYHA Class II. There were no deaths;
three patients underwent mitral valve replacement (MVR). Ninety-eight percent of patients with
a score of more than 8 (n =43) were NYHA Classes III and IV before PMV; at follow-up, 58%
were NYHA Classes I and II. Seven patients who did not improve and were not surgical
candidates died 3.8±1.2 months after PMV. Nine patients who were surgical candidates
underwent elective MVR at 4+0.9 months after PMV. Repeat cardiac catheterization demonstrated restenosis in only one of 27 patients (4%) with a score of 8 or less. Mitral valve area after
PMV was 1.9±0.1 cm2 and at follow-up was 2±0.1 cm2 (NS). In contrast, in patients with a
score of more than 8 (n=10), mitral valve area decreased from 1.8±0.1 cm2 (after PMV) to
1.1±0.1 cm2 at follow-up (p <0.01). Restenosis was demonstrated in seven of 10 patients (70%)
with a score of more than 8. Multivariate analysis showed echocardiographic score and the
presence of atrial fibrillation as predictors of restenosis. At ventriculography, the severity of
mitral regurgitation after PMV decreased by one grade in 53% of patients. Thus, PMV
produces excellent immediate and follow-up results in patients with a score of 8 or less;
suboptimal results immediately after PMV, and hemodynamic restenosis are more likely to
occur in patients with a score of more than 8. (Circulation 1989;79:573-579)
P ercutaneous mitral balloon valvotomy (PMV)
is an alternative to surgical mitral commissurotomy for patients with mitral stenosis.1-6
We have previously demonstrated that age, the
presence of atrial fibrillation, fluoroscopic calcium,
severity of symptoms, and the effective balloon
dilating area all affect the immediate hemodynamic
results.17,8 But the best predictor of immediate
results is an echocardiographic "score" based on
the severity of mitral valve morphologic abnormalities.7,8 Although PMV produces immediate hemo-
dynamic improvement in most patients with mitral
stenosis, complications of the procedure and the
long-term outcome of PMV will be the best measure
of its usefulness. This study assesses the immediate
results and clinical follow-up of 100 consecutive
patients who underwent PMV at the Massachusetts
General Hospital. In addition, follow-up echocardiographic (n = 32) and catheterization (n = 37) findings are presented. We also identify factors that
appear to influence mitral valve restenosis.
Materials and Methods
From the Cardiac Catheterization Laboratory, Cardiac Unit
Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
Presented at the 60th Annual Scientific Sessions of the American Heart Association, Anaheim, California, 1987.
Address for correspondence: Igor F. Palacios, MD, Cardiac
Catheterization Laboratory, Massachusetts General Hospital,
Boston, MA 02114.
Patient Population
This study reports 100 consecutive patients who
underwent PMV at the Massachusetts General Hospital between July 1985 and October 1987. There
were 83 women and 17 men (mean age, 55 ± 5 years;
range, 14-87 years). Fifty-one patients were in
normal sinus rhythm, and 49 patients in atrial fibril-
574
Circulation Vol 79, No 3, March 1989
TABLE. Demographic Characteristics of 100 Patients Undergoing
Percutaneous Mitral Valvotomy
Echocardiographic score
cs8
>8
Age (yr)
Atrial fibrillation
Fluoroscopic calcium
(n=57)
(n=43)
49+2
22 (39%)
17 (30%)
63+2*
31 (72%)t
35 (81%)*
*p<O.OOOl.
tp<0.01.
lation. Before PMV, 25 patients were in New York
Heart Association (NYHA) functional Class IV, 67
in Class III, and eight in Class II.
Patients were followed for a mean period of 13 1
months (range, 2 weeks to 28 months). An end point
was reached if a patient died, had mitral valve
replacement, or could be evaluated clinically by
May 1988. An early end point was reached in 19
patients (seven deaths; 12 mitral valve replacements). The functional status of the patients was
determined at a follow-up visit by the authors or by
telephone interview. If patients could not be contacted, their local physician was called to determine
their clinical status. Symptoms before PMV and at
follow-up are reported according to the NYHA
classification of heart failure. In addition, mitral
valve area at follow-up was determined by cardiac
catheterization in 37 patients and by two dimensional echocardiography in 32 additional patients.
±
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Analysis of Data
Patients were divided into two groups according
to an echocardiographic score system described
previously.7,8 Leaflet rigidity, leaflet thickening,
leaflet calcification, and subvalvular thickening were
each scored from 0 to 4 (least to most). A high score
was tallied by patients with more severe disease
(thickened, rigid, and calcified valve leaflets associated with thickening of the subvalvular apparatus).
Fifty-seven patients had echocardiographic scores
of 8 or less, and 43 patients had scores of more than
8. The Table shows the demographic characteristics
of these two groups. Patients with echocardiographic scores of more than 8 were older, had a
higher frequency of atrial fibrillation, and had more
fluoroscopic calcium than those with echocardiographic scores of 8 or less.
Procedures
Percutaneous mitral balloon valvotomy. Written
informed consent approved by the Human Studies
Committee of the Massachusetts General Hospital
was obtained from each patient before PMV. PMV
was performed as previously described.1X6-8 All
patients were anticoagulated with coumadin before
and after PMV if they were in atrial fibrillation, had
a history of paroxysmal atrial fibrillation, or had a
previous embolus. All patients were given intravenous heparin (100 units/kg) immediately after achiev-
ing left atrial access by transseptal left heart catheterization. Effective balloon dilating area (EBDA)
was determined by standard geometric and trigonometric analysis and then normalized for body surface area (EBDA/BSA).8 PMV was performed with
the single balloon technique in 22 patients (EBDA,
4.3 ± 0.2 cm2) and the double balloon technique in 78
patients (EBDA, 7.1±0.1 cm2). Hemodynamic calculations were performed with standard formulas.1,8
Follow-up cardiac catheterization. Cardiac catheterization was performed in 37 patients (31 women
and six men) with a mean age of 47 ± 3 years at
9 ± 0.7 months after PMV. Before PMV, all patients
were NYHA Classes III and IV. At the time of
follow-up catheterization, 95% of the patients were
in Classes I and II. Although follow-up cardiac
catheterization was not done in a random fashion,
the demographic characteristics and pre-PMV and
post-PMV hemodynamics of this subgroup are similar to the entire group of 100 patients. Because
follow-up catheterization was done electively without regard to recurrent symptoms, the data collected are likely characteristic of the entire patient
population. To evaluate the relation of mitral valve
morphology to follow-up catheterization data,
patients were divided in two groups according to
the echocardiographic score. There were 27 patients
with echocardiographic scores of 8 or less (mean
age, 41 ± 3 years) and 10 patients with echocardiographic scores of more than 8 (mean age, 60 ± 3
years).
Transseptal left heart catheterization was used to
measure the mitral gradient so that the technique of
pressure measurement would be the same as at the
time of PMV. Cardiac output was measured with
the thermodilution and the Fick techniques. The
Gorlin equation was used for calculation of mitral
valve area. A diagnostic oxygen run was performed
to assess the presence of left-to-right shunting. An
increase of 7% or more in oxygen saturation was
required to make a diagnosis of left-to-right shunt at
the atrial level.9 Cine left ventriculography in the
450 right anterior oblique projection was performed
in 36 of the 37 patients to assess the severity of
mitral regurgitation. In one patient, cine left ventriculography was not performed because of renal
failure. The severity of mitral regurgitation before
PMV, immediately after PMV, and at follow-up
cardiac catheterization was rated from 1 + to 4 + as
previously described.' The degree of mitral regurgitation was assessed by an experienced cardiac
radiologist who was "blinded" as to the status of
the patient. Severity of mitral valve calcification
under fluoroscopy was graded from 1+ to 4+ as
previously described.' Two-dimensional and Doppler echocardiographic studies were performed as
previously described.7
Restenosis at follow-up was arbitrarily defined as
a loss of 50% or more of the gain in the mitral valve
area produced by PMV.
Palacios et al PMV Follow-up
MITRAL GRAV/ENT(mmH/g)
20
IM Pre
U Post
16
4
12
3
2,!5
_A
Eh
2.(0
p<.0I
I
FIGURE 1. Bar charts of hemodynamic changes produced by percutaneous mitral valvotomy in
patients with echocardiographic
scores of 8 or less and more than 8.
,I
5
1.)0
8
4
ECHO SCORE..
|MITRAL VALVYE AREA (ccm'5
CARD/AC OUTPUT(L/mln)
5
0.5k
1
<8
(n= 57)
>8
(n=43)
0'
575
< 8
>8
0.0'
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Statistical analysis. Comparison of variables
before PMV, immediately after PMV, and at followup was performed with analysis of variance and the
Newman-Keuls multiple comparison test. Comparison of variables between patients with echocardiographic scores of 8 or less and those with an
echocardiographic score of more than 8 was performed using the unpaired Student's t test. Changes
were considered significant when p<0.05.
To identify factors associated with immediate
outcome of PMV, univariate and stepwise multiple
regression analyses of 16 demographic and hemodynamic variables were performed in the 100
patients. The variables included age, sex, EBDA,
EBDA/BSA, the number of balloons used (single
versus double balloon technique), fluoroscopic presence of calcium, degree of mitral regurgitation,
echocardiographic score, rhythm, NYHA functional Class before PMV, and the hemodynamic
determinations before PMV (mitral gradient, cardiac output, mitral valve area, pulmonary artery
pressure, left atrial pressure, and pulmonary vascular resistance).
In an attempt to identify factors associated with
restenosis, univariative and stepwise multiple regression analyses of 10 variables were performed in the
37 patients who underwent repeat cardiac catheterization. The variables included age, sex, EBDA,
EBDA/BSA, fluoroscopic presence of calcium, echocardiographic score, rhythm, NYHA functional class
before PMV, and the mitral valve area before and
after PMV.
All statistical testing was performed with BMDP
statistical software on a Digital Vax 11-780
computer (Digital Equipment Corp, Marlsboro,
Massachusetts).
Results
Immediate Results
The hemodynamic results produced by PMV in
patients with echocardiographic scores of 8 or less
and more than 8 are shown in Figure 1. PMV
resulted in a significant decrease in mitral gradient
and a significant increase in cardiac output and
mitral valve area in both groups of patients. However, the increase in mitral valve area was greater
in patients with echocardiographic scores of 8 or
less. In this group, PMV resulted in an increase in
mitral valve area from 0.9±0.1 to 1.9±0.1 cm2
(p < 0.01). A "good" hemodynamic result (defined
as a post-PMV mitral valve area, >1.5 cm2) was
observed in 50 of the 57 patients (88%) with echo
scores of 8 or less.
In patients with echocardiographic scores of more
than 8, PMV resulted in an increase in mitral valve
area from 0.9 0.1 to 1.6 0.1 cm2 (p < 0.01). A good
hemodynamic result occurred only in 19 of the 43
patients (44%) and a suboptimal result in the other
24 patients (56%) in this group. Comparison of the
difference in the increase in mitral valve area produced by PMV in patients with echo scores of 8 or
less and more than 8 was statistically significant
(p <0.006).
Univariative analysis demonstrated that the
increase in mitral valve area with PMV is directly
related in EBDA/BSA (p = 0.03) and inversely
related to the echocardiographic score (p = 0.00002),
the presence of atrial fibrillation (p = 0.0002), fluoroscopic calcium (p = 0.0006), and older age
(p= 0.00007). Multiple stepwise regression analysis
demonstrated that the independent predictors of the
increase of mitral valve area with PMV are the
echocardiographic score (p = 0.007), the presence of
atrial fibrillation (p = 0.005), and mitral regurgitation
before PMV (p =0.02).
The immediate outcome of PMV was also related
to whether one or two balloons were used for PMV.
Mitral valve area increased from 0.8 0.1 to 1.4 0.1
cm2 in the 22 patients in whom PMV was performed
with the single balloon technique (EBDA, 4.3 + 0.2
cm2). In contrast, mitral valve area increased from
0.9±0.1 to 1.9 ±0.1 cm2 in the 78 patients in whom
PMV was performed using the double balloon technique (EBDA, 7.1 ±0.1 cm2). Comparison of the
difference in the increase in mitral valve area produced by PMV in patients treated with single and
double balloon technique was statistically significant (p=0.001).
±
±
±
±
Complications
One patient (1%) died soon after PMV as previously described.' Two patients developed transient
Circulation Vol 79, No 3, March 1989
576
Echo Score '8, n = 57
NYHA
Class
Pre PMV
~~~681%
1
Echo Score > 8, n = 43
Follow up
Post PMV
461
ir
1%
(7)
2
(7)
il
72
(411
3 7%
(4)
46 81%l
NYHA
Class
Pre PMV
Post PMV
37%
I
(461
12%
(7
4
7%
(4)
(1
mn
61
2%
O
(261
37%
(1)
FIGURE 2. Schema of New York Heart Association
(NYHA) functional classification of the 100 patients
before percutaneous mitral valvotomy (PMA) and at
follow-up forpatients with echocardiographic scores
of 8 or less (left panel) and for patients with echocardiographic score of more than 8 (right panel).
10~~~~~~
9 21%,
21
(991)
26%
(1
10 23%
716%
2%
S1
(v9)
Follow-up
16 37%
111 161]/)
(10)1
/~ ~
tDeaths.
(7)X)1)
t
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(less than 24 hours' duration) complete atrioventricular block requiring temporary pacing. Two patients
developed thromboembolic events, including a
stroke in one patient (1%). Severe mitral regurgitation occurred in only one patient (1%). Left-to-right
shunt through the interatrial communication was
demonstrated by oximetry at the end of the procedure in 20 patients (20%). The pulmonary to systemic flow ratio of the atrial shunt was less than 2: 1
in 16 patients and equal or greater than 2: 1 in four.
Pericardial tamponade occurred in two patients
(2%). Both patients were successfully treated in the
catheterization laboratory with pericardiocentesis
and did not require emergency surgery.
Follow-up Results of Patients With
Echocardiographic Scores of 8 or Less
Clinical follow-up. The New York Heart Association functional classification of the 57 patients with
echocardiographic scores of 8 or less before PMV,
1 week after PMV, and at follow-up are shown in
Figure 2 (left panel).
Before PMV, 88% of the patients with echocardiographic scores of 8 or less were NYHA Classes
III and IV. At follow-up, 81% were Class I and 12%
were Class II. There were no deaths in this group of
patients. Three of the four patients in Class III after
PMV underwent elective mitral valve replacement
at 5.3± 1.6 months after PMV because of mitral
regurgitation and heart failure. Their mitral valve
areas after PMV were 2.1, 2.0, and 1.7 cm2; two
patients had 2+ and one patient had 3+ mitral
regurgitation.
Follow-up cardiac catheterization. Figure 3 (left
panel) shows the mitral valve areas before PMV,
immediately after PMV, and at follow-up cardiac
catheterization of 29 patients with echocardiographic scores of 8 or less. There was no significant
difference in the mean calculated mitral valve area
at follow-up catheterization compared with that
immediately after PMV. Mitral valve area at followup catheterization was 2.0 ± 0.1 cm2 compared with
1.9±0.1 cm2 immediately after PMV. Restenosis
was present in only one patient (4%) in this group of
patients.
\16%
Follow-up echocardiography. Sixteen additional
patients with an echocardiographic score of 8 or
less who did not have follow-up cardiac catheterization had evaluation of their mitral valve areas at
follow-up by two-dimensional and Doppler echocardiography. In this group of patients, the mean mitral
valve area at follow-up was 1.6±0.1 cm2 compared
with 1.6 ± 0.1 cm2 immediately after PMV. Restenosis by echocardiography was demonstrated in only
one of these 16 patients (6%).
Follow-up Results of Patients With
Echocardiographic Scores of More Than 8
Clinical follow-up. The New York Heart Association functional classification of the 43 patients with
echocardiographic scores of more than 8 before
PMV, 1 week after PMV, and at follow-up is shown
in Figure 2 (right panel). Before PMV, 98% of the
patients with echocardiographic scores of more
than 8 were in NYHA Classes III and IV. At
follow-up, 58% of the patients in this group were
Classes I and II. Eighteen of the 24 patients in
whom PMV resulted in a suboptimal result remained
in NYHA Classes III and IV after PMV. Seven of
these patients who were considered nonsurgical
candidates because of advanced age and associated
major medical problems in addition to end-stage
Echo Score '8, n- 27
3
141
---
R
OL_
Pre PMV
j
Post PMV
Follow-up
1
Pre PMV
Post PMV
Follow-up
J
FIGURE 3. Plots of mitral valve area before percutaneous mitral valvotomy (PMV), immediately after PMV,
and at follow-up for patients with echocardiographic
scores of 8 or less and more than 8.
Palacios et al PMV Follow-up
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mitral stenosis died at 3.8 ±1.2 months after PMV.
All died from congestive heart failure, including one
patient who was readmitted 2 weeks after PMV
with sepsis secondary to a dental abscess. Nine of
the remaining 11 Class III and Class IV patients
who had a suboptimal result with PMV and were
surgical candidates underwent mitral valve replacement at 4±0.9 months after PMV.
Follow-up cardiac catheterization. Figure 3 (right
panel) shows the mitral valve areas of 10 patients
with echocardiographic scores of more than 8 before
PMV, immediately after PMV, and at follow-up
cardiac catheterization.
Patients with echocardiographic score of more
than 8 had a significant decrease in mitral valve area
at follow-up when compared with immediate postPMV results. Mean mitral valve area had decreased
from 1.8 ± 0.1 cm2 immediately after PMV to 1.1 ± 0.1
cm2 at follow-up catheterization (p < 0.01). Restenosis was present in seven patients (70%) of this
group.
Follow-up echocardiography. Sixteen additional
patients with echocardiographic scores of more
than 8 who did not have follow-up cardiac catheterization had evaluation of their mitral valve area at
follow-up by two-dimensional and Doppler echocardiography. In this group of patients, the mean mitral
valve area at follow-up was 1.5±0.1 cm2 compared
with 1.6±0.2 cm2 immediately after PMV. Restenosis was demonstrated in four of these 16 patients
(25%).
Univariative analysis demonstrated that the
decrease in mitral valve area at follow-up was
directly related to older age (p= 0.01), higher echocardiographic score (p = 0.0004), and the presence
of fluoroscopic calcium (p = 0.005) and inversely
related to EBDA/BSA (p= 0.05). Multiple stepwise
regression analysis identified echocardiographic
score (p = 0.0004), F= 15.16) as the only independent
predictor of restenosis (A mitral valve area, 0.136843
x echocardiographic score + 0.953064).
Mitral Regurgitation
Immediate results. Fifty-three percent of patients
undergoing PMV had an increase in mitral regurgitation of one grade or more immediately after PMV.
Severe mitral regurgitation (4 +) was present in only
1 patient (1%). There was no need for emergency
mitral valve replacement.
Follow-up results. Figure 4 shows the changes in
the degree of mitral regurgitation before and after
PMV and at follow-up in 36 of the 37 patients who
underwent repeat cardiac catheterization.
PMV resulted in an increase in the severity of
mitral regurgitation compared with pre-PMV status
in 19 of the 36 patients (53%). At follow-up ventriculography, the severity of mitral regurgitation
decreased by one grade in 10 of these 19 patients
(53%) and increased by one grade in one patient.
MR Grode
0
2
Pre PMV
Follow-up
Post PMV
8
28)
14 39%
22
(8)
3 (12)
(14)
577
56%
14
7
(20)
%
(9
(3)3
3 2~ ~ %21
(PMV),~afe
~~~~19
8%,ad tfllw
FIGURE 4. Schema of changes in the degree of mitral
regurgitation before percutaneous mitral valvotomy
(PMI7), after PMW, and a t follow-up.
Left to Right Shunting
Immediate results. A significant step up (.7%
increase) in oxygen saturation was demonstrated in
20% of the patients undergoing PMV. The pulmonary to systemic flow ratio of the shunt was 1.6:1 or
less in 11 patients, between 1.7:1 and 2:1 in five
patients, and more than 2:1 in four patients.
Follow-up results. Seventeen of the 20 patients
with post-PMV left-to-right shunt had evaluation of
the atrial septal defect at 10±1 months after PMV
by either cardiac catheterization, color flow Doppler echocardiography, or cardiac surgery. The other
three patients died before follow-up evaluation of
the atrial defect. Follow-up evaluation showed no
evidence of atrial communication in 11 of these 17
patients (65%).
Of the 37 patients who had follow-up right heart
and transseptal left heart catheterization, there were
five patients who had evidence of left-to-right shunting immediately after PMV, yet evidence of shunting at follow-up catheterization was demonstrated
in only one patient. In most of these patients, repeat
transseptal puncture was necessary at the time of
follow-up catheterization, which indicates that the
atrial septal puncture done at PMV had closed. Of
four additional patients who had right heart catheterization with diagnostic oxygen run, a left-to-right
shunt was demonstrated in two patients. In each,
the pulmonary to systemic flow ratio of the shunt
was 1.7:1. Three patients did not have cardiac
catheterization but were evaluated by color flow
Doppler echocardiography. Left-to-right shunt was
demonstrated in one. Finally, among the 12 patients
who underwent elective mitral valve replacement,
there were five patients who had evidence of leftto-right shunting immediately after PMV. However,
at surgery, an iatrogenic atrial septal defect was
seen and closed in only two of these five patients.
Discussion
Our study shows that the symptomatic and hemodynamic improvement produced by PMV persists
as patients are followed up for more than 2 years.
578
Circulation Vol 79, No 3, March 1989
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This study also demonstrates that the echocardiographic score, balloon size, age and the presence of
atrial fibrillation, fluoroscopic calcium, and mitral
regurgitation are the more important predictors of
the increase of mitral valve area with PMV.
The best immediate results of PMV are in patients
with echocardiographic scores of 8 or less whose
mitral valves are mobile, thin, and minimally or not
calcified and who have little or no subvalvular
fibrosis.7,8 Our study shows that a good hemodynamic outcome of PMV (defined as post-PMV mitral
valve area. >1.5 cm2) is obtained in 88% of these
patients. The best long-term functional, echocardiographic, and hemodynamic results are also seen in
patients with a score of 8 or less. When PMV produces good hemodynamic results in these patients,
restenosis by echocardiographic or cardiac catheterization or both is unlikely to occur at follow-up.
In contrast, patients with echocardiographic scores
of more than 8 whose echocardiograms demonstrate severe subvalvular disease, extensive valvular thickening and calcification, and a rigid mitral
valve have a high chance of having a suboptimal
hemodynamic result with PMV. In our patients, a
good hemodynamic result with PMV occurred in
only 44% of patients with echocardiographic scores
of more than 8. Eighteen of the 24 patients in this
group with a suboptimal result of PMV remained in
NYHA Classes III and IV after PMV. Of these 18
patients at an average follow-up of 4 months, nine
surgical candidates had mitral valve replacement,
and seven nonsurgical candidates died. Even if a
good hemodynamic result is produced in patients
with echocardiographic scores of more than 8,
restenosis can frequently be demonstrated by cardiac catheterization at follow-up. However, it is
possible that our 37 patients who underwent followup cardiac catheterization may not be representative of our entire population because the selection was not random. Nevertheless, there were no
significant differences in the demographic characteristics, and the pre-PMV and post-PMV hemodynamics of this subgroup generally compared with
our entire PMV population. Although univariative
analysis identified age, echocardiographic score,
evidence of calcium at fluoroscopy, and EBDA/
BSA as variables predictive of a decrease in mitral
valve area at follow-up, multiple stepwise regression
analysis identified the echocardiographic score as the
single most important factor predictive of restenosis.
Our findings are in agreement with previous
reports of surgical mitral commissurotomy.10-17 The
best results of surgical mitral commissurotomy occur
in patients who have little or no calcium deposition
in the mitral valve.10-14 Those studies identified
significant mitral calcification and the presence of
atrial fibrillation as the most important factors
adversely influencing both immediate and long-term
results.1014 Unfortunately, most follow-up studies
of surgical mitral commissurotomy have reported
only functional results.10-15 Studies that reported
follow-up hemodynamic parameters lack immediate
postcommissurotomy hemodynamic data.16'17 Our
data show that a persistent small increase in mitral
valve area produces improvement in clinical symptoms even when some restenosis has occurred. Five
of seven patients with echocardiographic score of
more than 8 and hemodynamic restenosis but still
with a mitral valve area greater than before PMV
remained in the improved NYHA functional class
that they reached after PMV. An attempt to compare our hemodynamic data with previous surgical
results is, therefore, difficult.
The clinical usefulness of PMV can only be
assessed by follow-up data and acute complications. Our follow-up data is encouraging. The risks
of mortality, thromboembolism, and severe mitral
regurgitation are similar for surgical mitral commissurotomy and PMV.10-15 In contrast to surgical
commissurotomy, 20% of our patients had evidence
of left-to-right shunting through the atrial septum
immediately after PMV. In 80% of them, the magnitude of the shunt was small with a pulmonary to
systemic flow ratio less than 2:1. We demonstrated
evidence of left-to-right shunting by oximetry in
only one of the 37 patients who underwent followup catheterization. Among these 37 patients, there
were five patients with evidence of left-to-right
shunting immediately after PMV. In addition, no
atrial communication was discovered at surgery in
nine of 12 patients undergoing elective mitral valve
replacement. In this latter group of patients, a
left-to-right shunt had been demonstrated in five
patients immediately after PMV. Thus, although the
atrial septum has a small tear produced by PMV,'18
it is likely that it closes later in the majority of
cases. Left-to-right shunting might persist if the
result of PMV is suboptimal. Persistence of a high
left atrial pressure and the resultant high pressure
gradient between left and right atrium could cause
enough flow to keep the defect open. Conversely, a
good result of PMV with its attendant decrease in
left atrial pressure minimizes the atrial pressure
differential and may allow septal closure. Thus, if
patients do not have a good result after PMV and
mitral valve replacement is done later, surgeons
should be aware of the possibility of an atrial septal
defect that should be repaired at the time of mitral
valve surgery.
Mitral regurgitation may occur after surgical mitral
commissurotomy.14"15 Approximately half of the
patients undergoing PMV have a small increase in
mitral regurgitation.18 Severe mitral regurgitation is
rare. We have previously reported that an increase
in mitral regurgitation cannot be predicted from any
features of the valve or subvalvular apparatus,
clinical characteristics of the patient, or technical
aspects of the procedure. 19 This study also indicates
that the increase in the severity of mitral regurgitation that was produced by PMV decreases in more
than half of patients at follow-up catheterization.
There may be three mechanisms responsible for the
Palacios et al PMV Follow-up
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decrease in mitral regurgitation: 1) reversible mitral
valve "stretching" by PMV; 2) fibrosis and healing
of the end of the commissures, which may diminish
mitral regurgitation due to excessive splitting of the
commissures to the mitral annulus; and 3) improvement in transient papillary muscle dysfunction
caused by balloon trauma to the papillary muscle at
the time of PMV. Mitral regurgitation is tolerated
well clinically. In our patients, there was no deterioration in NYHA class immediately after PMV.
We conclude that 1) patients who have low echocardiographic scores (8 or less) are the best candidates for percutaneous mitral valvotomy; not only
do they have a good immediate result from PMV,
but their follow-up shows on-going clinical, echocardiographic, and hemodynamic stability; 2) patients
with echocardiographic scores of more than 8 have
a 56% chance of having a suboptimal immediate
result with PMV; although they could have a good
initial result from PMV, our study shows that a high
percentage of them have restenosis demonstrated
by cardiac catheterization or echocardiography at
follow-up; and 3) it is our impression that if the echo
score is more than 12, it is unlikely that PMV will
produce a good immediate or long-term result.
These patients, if they are surgical candidates, are
better suited for surgical mitral valve replacement,
and PMV should be undertaken only if surgery is
not an option. Clearly, patients will fall into a
continuum of echocardiographic scores. If the score
is 9-12, individual consideration may allow identification of patients who might have the most favorable result from PMV. In this group, we feel that
valve thickening, subvalvular fibrosis, and calcification are the factors that adversely influence the
outcome of PMV. If there is severe subvalvular
apparatus disease, relief of mitral obstruction with
PMV may be impossible.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
Acknowledgments
We thank Elizabeth H. Block for her help in
collecting the data and Olga Viasus for her secretarial assistance in typing the manuscript.
17.
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KEY WORDS * therapeutic catheterization * mitral balloon
mitral stenosis * balloon valvuloplasty
valvotomy
.
Follow-up of patients undergoing percutaneous mitral balloon valvotomy. Analysis of
factors determining restenosis.
I F Palacios, P C Block, G T Wilkins and A E Weyman
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Circulation. 1989;79:573-579
doi: 10.1161/01.CIR.79.3.573
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