D. De Wolf, K. Vanderbruggen, A. Verbist, B.
Suys, H. Verhaaren, K. François, T. Bove, J. Panzer, W. Decaluwe, K. De Groote,
D. Matthys
Center for Congenital
Heart Disease, Anna Blancquaert, Ghent and Antwerp University Hospitals
Since
its introduction in 1984, balloon aortic valvuloplasty has replaced surgical
valvotomy as first-line treatment for neonates, children and young adults with
congenital aortic stenosis. We reviewed our own single center experience over
the last 14 years and discussed the possible impact of recent technical
modifications in interventional and surgical techniques.
Population data:
from 1991 until 2004 72 balloon valvulotomies were performed in 60 patients. In
56 patients follow up was complete (table1). 22 had their first dilation below
the age of 3 months (group 1) and 34 were older than 3 months (4m-17 years,
group 2).
Technique of dilatation:
All patients were fully anesthetized. Except in 2 cases, all aortic valves were
crossed in a retrograde fashion (femoral artery approach). The aortic valve was
crossed with a soft tip straight Terumo® (Tokyo, Japan) 0.018” or 0.025”
guide wire in order to enter the left ventricle with a soft tip 4F or 5F right
Judkins catheter. Over a stiff exchange guide wire a low profile balloon with an
initial balloon/valve ratio of 0.9 was positioned through the stenotic valve and
rapidly inflated. In recent years we used intravenous adenosine in the older
patient group, and since 1 year rapid RV pacing to prevent balloon migration
during inflation.
Immediate results:
the initial balloon dilation achieved comparable immediate gradient reduction in
both groups: 60% in group 1 and 58% in group 2. Only one patient in group 2
showed no gradient reduction at all, in the other patients gradients decreased
below intervention thresholds.
Complications:
aortic incompetence was common after dilation reaching grade 2 and 3 in 6/22
patients of group 1 and 7/34 patients of group 2. Four patients in group 1 died,
none in group 2. One patient presenting with a coarctation, mitral stenosis,
aortic stenosis with annular hypoplasia and fibro-elastosis died after 2 months,
one patient with fibro-elastosis died suddenly 2 days after an uneventful
dilation, one patient with mitral stenosis, coarctation, aortic stenosis and
annular hypoplasia died as a consequence of therapy resistant low cardiac
output, and one patient with coarctation, aortic stenosis and annular hypoplasia
died after 1 week due to LV failure despite only moderate post procedural AI. In
retrospect, our current policy would nowadays direct 2 of these patients towards
a univentricular Norwood type correction and the last to a neonatal Ross.
Arterial complications were rare: 1 femoral artery thrombosis in group 1 and 3
in group 3. This paradoxical result can be explained by our policy of post
procedural heparinisation during 24 hours in the youngest patients.
Mid-term results:
aortic incompetence was progressive (up to grade 2 or more) in 18% of patients
of group 1 and 14 % of group 2. Re-intervention was common: 4% of patients in
group 1 ended up with a repeat balloon dilatation only, 22 % with aortic valve
surgery (eventually preceded by repeat balloon valvuloplasty). In group 2, eight
percent of patients got repeat balloon dilation only; again 29% needed surgery.
The mean time interval between the initial dilation and the re-intervention was
3 years in group 1 (range 1m-6 years) and 4 years in group 2 (range 1 m-10
years). In 3 patients who underwent aortic valve surgery, aortic incompetence
could directly be contributed to the balloon dilation: one tear near the
commissure, one tear of a leaflet and one cusp avulsion. In the patients who
needed a re-intervention or died, a strong association was found with
coarctation: 41% compared to 14% in the other patients.
Discussion
Despite
good immediate results, balloon valvuloplasty remains a palliative procedure.
More than 50% of patients require a re-intervention within 10 years. The
indications for balloon dilation and surgery are essentially the same. Neonates
with duct dependent lesions or ventricular dysfunction and/or a Doppler gradient
above 60 mmHg are candidates for balloon dilation if by morphological criteria
biventricular repair is advocated. In older children a gradient of more than 80
mmHg, symptoms or EKG changes remain clear indications. The indications in
asymptomatic children and young adults with Doppler gradients between 50 and 80
mmHg are more controversial: if untreated, sudden death has been described,
although mostly in patients with inadequate follow up.
Technique: long, low profile balloons are used with a balloon/valve ratio of less
than 0.9-1 to minimize the risk of aortic incompetence. The approach can be
retrograde or antegrade. The antegrade approach could reduce the risk of femoral
artery damage in newborns and theoretically reduce aortic incompetence (unproven
until now). Intravenous adenosine and rapid right ventricular pacing are
advocated by some to reduce balloon migration during inflation in order to
prevent uncontrolled damage to the aortic valve, in order to reduce severe post
dilation incompetence.
Immediate
results: mortality is essentially confined to the
newborn group, but reduced to less than 5% if patients with hypoplastic left
sided structures are redirected for univentricular repair. Short-term gradient
reduction is excellent and comparable to simple surgical valvotomy. Moderate or
severe aortic incompetence occurs in 15-25%. Recently, sophisticated surgical
valve repair with improved immediate results has been proposed as an alternative
to balloon or surgical valvotomy, but sufficient data are not yet available.
Long
term results: of concern is the high rate of re-intervention
for recurrent stenosis and progressive aortic incompetence. In recent studies,
intervention free survival was between 50 and 60% after 10 years and even below
30% for patients who underwent balloon dilation during the first 2 months of
life. However, repeat balloon dilation is more frequent in the first year in
newborns since in an attempt to avoid severe incompetence, balloon sizes with a
balloon/valve ratio of less than 0.9 are preferred, accepting less gradient
reduction. Severe aortic incompetence can in some instances be treated with
surgical valvuloplasty, deferring valve replacement for another 4 to 5 years,
but valve replacement for severe incompetence has been described in 10-20% on
mid term follow up (up to 10 years).
Recent
advances: in inoperable elderly patients with calcified
aortic valve stenosis, aortic valve replacement with a percutaneously implanted
stented equine valve has been achieved successfully. It is too early to
speculate on its eventual use in young adults with congenital aortic valve
stenosis.
Conclusion: balloon aortic valvuloplasty offers good immediate results with
reasonable morbidity and mortality. It remains a palliative procedure on the
long term, but in many instances valve replacement can be deferred for many
years in a population of growing and very active patients.
References
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valvuloplasty for neonatal aortic stenosis. Circulation 2005;111:451-458.
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Early experience with percutaneous transcatheter implantation of heart valve
prosthesis for the treatment of end-stage inoperable patients with calcific
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