Download Predisposing factors of valve regurgitation in complete

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JACC Vol. 32, No. 5.
November 1, 1998:1449 –53
Predisposing Factors of Valve Regurgitation in Complete
Atrioventricular Septal Defect
KIYOSHI SUZUKI, MD, PHD, KATSUHIKO TATSUNO, MD, PHD,† TOSHIO KIKUCHI, MD,*
SHIGEKAZU MIMORI, MD, PHD
Tokyo and Chiba, Japan
Objectives. We sought to determine the intrinsic risk factors of
valve regurgitation in complete atrioventricular septal defect.
Background. Progression of regurgitation varies in each case,
although the structure of the common atrioventricular valve itself
is a predisposing factor.
Methods. In 90 consecutive patients undergoing surgical repair,
we evaluated the preoperative and postoperative regurgitation,
valve morphology, age at surgery and associated anomalies. A
regurgitation jet with a high velocity reaching the deep left atrial
wall by echocardiography was estimated as marked regurgitation.
Results. None of the 40 patients with Rastelli type C and an
undivided inferior bridging leaflet had preoperative regurgitation
in the first year of life, and 12% of them (95% confidence intervals
[CI]: 0% to 28%) showed regurgitation at the age of 2. Of the
remaining 50 with Rastelli type A and/or a divided inferior leaflet,
regurgitation was determined in 21% (95% CI: 6% to 35%) of those
1 year old and in 49% (95% CI: 29% to 69%) of those 2 years old
(p < 0.01). All patients underwent corrective surgery using the
double-patch technique, with the “cleft” being sutured adequately.
Irrespective of the valve morphology, regurgitation remained in
52% (12 of 23) of those with preoperative regurgitation, whereas
regurgitation developed postoperatively in 28% (16 of 58) of those
without regurgitation (p < 0.001).
Conclusions. Those with Rastelli type C and an undivided
inferior leaflet had a lesser degree of progression of preoperative
regurgitation. However, regurgitation was likely to exist even after
adequate repair once regurgitation had already advanced. Therefore, early primary repair before progression of the regurgitation
may be the key to maintaining better competence of the atrioventricular valve.
(J Am Coll Cardiol 1998;32:1449 –53)
©1998 by the American College of Cardiology
The results of surgical repair for atrioventricular septal defect
with a common atrioventricular junction and orifice (the
complete type) have improved markedly in the past few
decades (1– 4); however, valve regurgitation before and after
surgery still remains an important issue (2–10). Because this
malformation is characterized by not only a deficiency of the
septum but also by an abnormal structure of the atrioventricular valve (11,12), there is an inherent problem of keeping the
competence of the valve even after complete repair. Annular
dilatation (10,13,14) and degeneration of the leaflets (6) have
been considered to precipitate regurgitation, whereas little
attention has been paid to the valve morphology itself (5,13).
Since Rastelli et al. (15,16) classified this anomaly according to
the configuration of the superior bridging leaflet, their classification has been widely used to delineate the structure of the
atrioventricular valve. But one of the shortcomings of this is
neglect of the different subtypes of the inferior bridging leaflet,
which may have allowed us to overlook an inherent risk factor
in the valve structure. The objective of our study, therefore, was to
review the precise morphology of the atrioventricular valve in
patients undergoing surgical repair and to clarify the predisposing
factors of preoperative and postoperative regurgitation.
From the Department of Pediatrics and *Department of Cardiac Surgery,
The Sakakibara Heart Institute, Tokyo; †Department of Cardiovascular Surgery,
Chiba Cardiovascular Center, Chiba, Japan. This study was supported by 1997
research grants from the Mokichi Okada Association Health Science Foundation, Tokyo, and the Sakakibara Heart Institute, Tokyo.
Manuscript received March 12, 1998; revised manuscript received June 15,
1998, accepted July 2, 1998.
Address for correspondence: Dr. Kiyoshi Suzuki, Department of Pediatrics,
The Sakakibara Heart Institute, 2-5-4 Yoyogi, Shibuya-ku, Tokyo 151-0053
Japan. E-mail: [email protected].
©1998 by the American College of Cardiology
Published by Elsevier Science Inc.
Methods
Patients. We studied a total of 90 consecutive patients with
a complete atrioventricular septal defect undergoing corrective
surgery between January 1982 and December 1997 in the
Sakakibara Heart Institute in Tokyo. Cases with isomerism of
the atrial appendages or a marked dominance of either
ventricle were excluded from this study. The age at the time of
complete repair ranged from 1 month to 13 years. There were
36 males and 54 females, and 78 patients (87%) had Down
syndrome. Associated congenital heart abnormalities, other
than secundum atrial septal defect and patent ductus arteriosus, were present in 15 patients (17%). Thirteen patients
showed the morphologic features of tetralogy of Fallot, and the
remaining 2 patients had coarctation of the aorta. Palliative
pulmonary artery banding was used as an initial step in 12
patients (13%). All 90 patients received cardiac catheterization
within 2 months prior to the complete repair, which revealed
severe pulmonary hypertension (greater than 80% of the
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SUZUKI ET AL.
VALVE REGURGITATION IN AVSD
JACC Vol. 32, No. 5.
November 1, 1998:1449 –53
Table 1. Predisposing Factors of Preoperative Valve Regurgitation
Marked
Regurgitation
Age at operation
, 12 months
^ 12 months
Inferior bridging leaflet
Undivided
Divided
Superior bridging leaflet
Type A
Type C
Associated anomalies
No
Yes
Previous PA banding
No
Yes
Down syndrome
No
Yes
Number
Present
(%)
Absent
(%)
Odds Ratio
(Univariate)
51
39
5 (10)
21 (54)
46 (90)
18 (46)
1.0
10.7 (3.2– 40.9)†
, 0.001
1.0
, 0.001
13.4 (3.8 – 46.8)
68
22
14 (21)
12 (55)
54 (79)
10 (45)
1.0
4.6 (1.5–14.6)
, 0.001
1.0
, 0.01
6.5 (1.8 –23.5)
42
48
14 (33)
12 (25)
28 (67)
36 (75)
1.0
1.5 (0.5– 4.2)
NS (p 5 0.49)
75
15
20 (27)
6 (40)
55 (73)
9 (60)
1.0
1.8 (0.5– 6.6)
NS (p 5 0.35)
78
12
24 (31)
2 (17)
54 (69)
10 (83)
1.0
0.5 (0.05–2.4)
NS (p 5 0.50)
12
78
6 (50)
20 (26)
6 (50)
58 (74)
1.0
0.4 (0.08 –1.15)
NS (p 5 0.10)
p Value
Odds Ratio*
(Multivariate)
p
Value
The multiple logistic regression model was used for statistical analysis. *Adjusted odds ratios were obtained by best
subset selection method. †95% confidence intervals in parentheses. PA 5 pulmonary artery.
systemic blood pressure) and a large pulmonary to systemic
flow ratio (greater than 2.0) in all except those with tetralogy of
Fallot or those with a previous banding procedure.
Measurements. We evaluated the presence of regurgitation of the atrioventricular valve by echocardiography before
and after surgical repair. A regurgitation jet with a high
velocity reaching the deep left atrial wall in the echocardiogram was estimated as marked regurgitation (5,8,9). The
precise morphology of the atrioventricular valve was inspected
carefully during the operation. To determine predisposing
factors of valve regurgitation and operative mortality, we
evaluated the following variables: morphology of the superior
and inferior bridging leaflets, age at corrective surgery, the
presence of associated anomalies, previous pulmonary artery
banding and Down syndrome.
Analysis of data. The multiple logistic regression model
was used to estimate presenting features as risk factors of valve
regurgitation before surgery. The Kaplan–Meier curve was
constructed to determine actuarial freedom from preoperative
regurgitation, and the generalized Wilcoxon test was performed for the statistical analysis between the groups. The
relationship between preoperative and postoperative regurgitation was assessed by the McNemar test, and the chi-square test
was used to compare the incidence between the noncontinuous
groups. A p value of ,0.05 was considered statistically significant.
Results
Preoperative valve regurgitation (Table 1). Of the 90 patients in the overall group, 26 (29%) showed marked regurgi-
tation before surgery. In 51 patients undergoing surgical repair
at an age of less than 1 year old, 5 (10%) had marked
preoperative regurgitation, whereas 54% (21 of 39) of those
aged 1 year or more at surgery had regurgitation (p , 0.001).
As for the morphology of the inferior bridging leaflet, 68
(76%) patients had an undivided morphology, and the remaining 22 (24%) had the leaflet partitioned by a slit or raphe (the
divided morphology). Marked regurgitation was determined
preoperatively in 21% (14 of 68) of those with an undivided
inferior leaflet, whereas 55% (12 of 22) of those with a divided
morphology showed regurgitation (p , 0.01). None of the
factors, such as the morphology of the superior bridging leaflet,
presence of associated anomalies, previous pulmonary artery
banding or Down syndrome, was related to the incidence of
preoperative regurgitation.
Forty patients (44%) had a free-floating superior bridging
leaflet (Rastelli type C) with an undivided inferior bridging
leaflet, and 8 (9%) had type C morphology with a divided
inferior leaflet. Rastelli type A morphology with an undivided
inferior leaflet was observed in 28 patients (31%), and the
remaining 14 (16%) showed type A with a divided inferior
leaflet. The actuarial freedom from preoperative valve regurgitation was almost the same among the groups, except for
those with type C and an undivided inferior leaflet (Fig. 1). In
this group, it was 100% at 1 year, 94% (95% confidence
intervals [CI], 82% to 100%) at 1.5 years and 88% (95% CI:
72% to 100%) at 2 years. In those with the other valve
morphologies, on the contrary, the actuarial freedom from
regurgitation was 79% (95% CI: 65% to 94%) at 1 year, 75%
JACC Vol. 32, No. 5.
November 1, 1998:1449 –53
Figure 1. Actuarial freedom from preoperative valve regurgitation by
the Kaplan–Meier method was almost the same among the groups,
except for those with Rastelli type C and an undivided morphology of
the inferior bridging leaflet (IBL).
(95% CI: 58% to 91%) at 1.5 years and 51% (95% CI: 31% to
71%) at 2 years (p , 0.01, Fig. 2).
Operative mortality. We performed corrective surgery in
all cases with the double-patch technique, and both bridging
leaflets and their supporting chords were never cut to place a
patch. The so-called cleft (the zone of apposition between the
bridging leaflets) was sutured adequately to keep the competence of the valve. There were nine operative deaths among
the overall group of 90 patients (10%). Five died from
refractory pulmonary hypertension and the remaining four
died as a result of low cardiac output secondary to myocardial
failure. As for their preoperative condition, three patients had
suffered intractable heart failure and the other two had
tetralogy of Fallot. The operative mortality decreased significantly over the period of this study from 21% (6 of 29) before
1990 to 5% (3 of 61) since then (p , 0.01). Two patients died
late, 3 and 10 years after the operation, of recurrent pneumonia and cerebral infarction. Accordingly, deaths from valve
regurgitation were not an important issue in this series.
Postoperative valve regurgitation. In the 81 patients who
survived the operation, the follow-up period ranged from 4
months to 15 years (median 6.3 years). Marked regurgitation
of the left atrioventricular valve was determined in 28 patients
(35%) after surgical repair. Irrespective of the valve morpholFigure 2. Those with Rastelli type C and an undivided inferior
bridging leaflet (IBL) had better competence of the atrioventricular
valve remaining than did those with the other valve morphologies (p ,
0.01 by the generalized Wilcoxon test). Solid lines 5 actuarial freedom
from preoperative regurgitation by the Kaplan–Meier method; dotted
lines 5 95% confidence intervals.
SUZUKI ET AL.
VALVE REGURGITATION IN AVSD
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Figure 3. Echocardiographic evaluation of atrioventricular valve regurgitation before and after surgical repair. Six of the 64 patients (9%)
without preoperative regurgitation and 3 of 26 patients (12%) with
marked regurgitation died after the operation. Of the remaining 58
patients without preoperative regurgitation, 42 (72%) showed no
regurgitation after surgery, but regurgitation developed postoperatively in 16 (28%). On the other hand, of the 23 patients with
preoperative regurgitation, regurgitation improved in 11 (48%), but
remained in 12 (52%) (p , 0.001 by the McNemar test).
ogy, regurgitation remained after the operation in 52% (12 of
23) of those with preoperative regurgitation. On the other
hand, marked regurgitation developed after surgery in 28% (16
of 58) of those without preoperative regurgitation (p , 0.001,
Fig. 3). Seven patients underwent reoperation for the advance
of regurgitation, from 1 month to 7 years after corrective
surgery. The regurgitation in those cases was caused mainly by
the remnant “cleft” with annular dilatation in four cases,
laceration of the leaflet in two and a thick and hardly mobile
superior bridging leaflet in the remaining one who subsequently received valve replacement. Of the overall 79 patients
followed regularly, 76 (96%) were in New York Heart Association class I and the remaining 3 (4%) were in class II
undergoing pharmacologic treatment. The incidence of asymptomatic regurgitation detected by echocardiography decreased
to 15% (5 of 33) in the last 4 years.
Discussion
Surgical mortality of complete atrioventricular septal defect
has improved dramatically in recent years (1– 4). Regurgitation
of the left atrioventricular valve, however, still remains a
problem and reoperation is indispensable in some cases (1–
3,7,9,13). A common atrioventricular valve postoperatively
never creates structurally normal mitral and tricuspid valves,
but it is possible to maintain better competence of the new
valves by eliminating the predisposing factors of regurgitation.
Predisposing factors of preoperative regurgitation. There
are several reports that preoperative valve regurgitation
progresses as patients become older (6,10,13,14). Yasui et al.
(6) reported that degeneration of the atrioventricular valve
increases with age. Michielon et al. (10) also described annular
dilatation as an important factor for regurgitation. In our
series, not only was an older age at operation an independent
risk factor for preoperative regurgitation, but also the mor-
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VALVE REGURGITATION IN AVSD
Figure 4. In those with Rastelli type A and/or a divided inferior leaflet,
the coaptation zone between both bridging leaflets is triangular or
diamond shaped (painted in black). On the other hand, those with
Rastelli type C and an undivided inferior leaflet, showing a lesser
degree of progression of preoperative regurgitation, do not have such
a structure.
phology of the inferior bridging leaflet. The actuarial freedom
curve indicated that those with Rastelli type C and an undivided inferior leaflet had a lesser degree of progression of
preoperative regurgitation than did those with the other
morphologies, namely, Rastelli type A and/or a divided inferior leaflet. The common atrioventricular valve may be more
frail in keeping the competence when the coaptation zone
between both bridging leaflets is triangular or diamond
shaped (Fig. 4). As patients become older, a large left-toright shunt results in annular dilatation, and the leaflets and
their supporting chords suffer degenerative changes. In
these instances, patients with such an aforementioned frailty
in the valve may have regurgitation sooner than those
without it.
Predisposing factors of postoperative regurgitation. Some
authors have argued that preoperative regurgitation is a risk
factor for operative mortality and postoperative regurgitation
(3,6,7,10,17,18), but others have argued against this proposition (2,4,13,14). The improvement in the surgical results is
likely related to the greater understanding of the structure of
this malformation, improved surgical technique and perioperative care. In fact, the operative mortality in our series
decreased from 21% to 5% over the last 16 years without any
relation to the incidence of preoperative regurgitation. However, our results also showed that regurgitation was likely to
exist after the repair once preoperative regurgitation had
already progressed. As mentioned above, the common atrioventricular valve was less resistant to the systemic blood
pressure when the inferior bridging leaflet was partitioned or
the superior bridging leaflet showed type A morphology. But at
surgery, each component is tightly sutured with a patch so that
it no longer becomes a coaptation zone but a part of the
annular ring of the new valve. We suspect, therefore, that
patients will have less chance of suffering postoperative regurgitation if the regurgitation is absent or the jet is located only
at the coaptation zone over the ventricular septum. But if the
regurgitation is left alone and exacerbates the annular
JACC Vol. 32, No. 5.
November 1, 1998:1449 –53
dilatation, degenerative changes and dislocation of the
whole valve (6,10,13,14), it will be difficult to stop the
regurgitation completely even with adequate repair and
annuloplasty (2,10,14).
As described previously, the first 6 months of life should be
the golden time for definitive repair (6,7,10,13,14,18) because
not only preoperative regurgitation, but also pulmonary vascular obstructive disease hardly develops at this period (19,20).
We have been performing corrective surgery routinely as soon
as the diagnosis was completed, and blood transfusion is
seldom necessary when patients weighed more than 4.0 kg. The
long-term prognosis remains to be clarified; however, none of
these cases had symptomatic regurgitation or was required to
continue medical treatment. The incidence of regurgitation
estimated by echocardiography also markedly decreased.
For a patient with complex anomalies in addition to an
atrioventricular septal defect, the time of surgical repair varies
in each case. In those with tetralogy of Fallot, for example, the
size of the pulmonary artery is also an important factor for
successful repair. Fortunately, almost always these cases had
type C morphology of the superior bridging leaflet (21) and
about 70% of them had an undivided inferior bridging leaflet.
We might be able to wait for the growth of the pulmonary
artery for a few years without much fear of progression of
regurgitation in some cases of this combination. Hypoplasia of
the left ventricle or an abnormal structure of the left atrioventricular valve, such as dual orifices and a small mural leaflet,
are other reasons for postponing surgical repair. Those patients often received pulmonary artery banding as an initial
step, although it remains to be established whether the banding
procedure delays the development of valve regurgitation
(3,9,18).
Study limitations. Our improved surgical technique and
perioperative care over the period of this study may have
biased the intrinsic risk factors of the common atrioventricular
valve and the recent decrease in the postoperative regurgitation. We evaluated the presence of valve regurgitation by
echocardiography, but this estimation may not always correlate
with symptomatic regurgitation because of its hypersensitivity.
Another important issue is that extrinsic factors other than the
age at surgery, such as infection and cyanosis, may also
influence the progression of preoperative regurgitation.
Conclusions. The development of valve regurgitation varied with the morphology of the common atrioventricular valve
in patients with complete atrioventricular septal defect. Those
with Rastelli type C and an undivided inferior bridging leaflet
had a lesser degree of progression of preoperative regurgitation than did those with the other valve morphologies. However, regurgitation was likely to remain even after adequate
repair once preoperative regurgitation had already advanced.
Therefore, primary repair in the first 6 months of life, before
the development of annular dilatation and degenerative
changes of the valve, may be the key to maintaining better
competence of the atrioventricular valve.
JACC Vol. 32, No. 5.
November 1, 1998:1449 –53
SUZUKI ET AL.
VALVE REGURGITATION IN AVSD
We thank Mr. Teruaki Kawai, Dr. Kazuo Nitta, Mr. Noriyuki Kawai and Mr.
Tadahiko Moriyama from the Mokichi Okada Association Health Science
Foundation, Tokyo, and Drs. Yukihiro Takahashi, Yasuo Murakami, Katsuhiko Mori and Yoshiho Hatai from the Sakakibara Heart Institute for their
help in preparing the manuscript. We also thank Mr. Katsunori Shimada from
the Department of Biostatistics, STATZ Corporation, for the statistical
analyses.
10.
11.
12.
13.
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