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Original Article
Observational Study of surgical closure of Ostium
Primum Atrial Septal Defect in thirty paediatric
patients
Suraj Wasudeo Nagre1, Manisha Suraj Nagre2
1
2
Department of CVTS, Grant Medical College and J J Hospital, Mumbai, India
Kasturba Hospital, Mumbai, India
Keywords: Premum ASD, Atrioventricular Septal Defect, Partial AV Canal
Abstract
Primum atrial septal defect (ASD) is a common congenital cardiac anomaly that is
typically repaired in the first years of life. Patients with isolated ostium primum atrial
septal defects (ASDs) have benefited from important recent advances in the diagnosis,
evaluation, and management of their conditions. Operative correction typically involves pericardial patch closure of the septal defect and closure of
associated
left atrioventricular valve cleft. This review will focus on thirty paediatric patients
with sizeable ostium primum atrial septal defects who do not have other major
associated cardiac defects.
*Corresponding author:
Dr Suraj Wasudeo Nagre, 31, Trimurti Building, J J Hospital Compound, Byculla, Mumbai, 400008, India
Email [email protected]; Mobile +91-9967795303
This work is licensed under the Creative Commons Attribution 4.0 License. Published by Pacific Group of e-Journals (PaGe)
Original Article
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INTRODUCTION
Unlike a ostium secundum atrial septal defect (ASD), the
ostium primum form of ASD is not amenable to device
closure in the cardiac catheterization laboratory. The
device is unable to be adequately seated secondary to an
inadequate inferior rim of atrial septal tissue and the
proximity of the defect to the atrioventricular (AV)
valves. A left-to-right atrial shunt is considered significant when the Qp/Qs ratio is greater than 1.5/1.0, or if it
causes dilation of the right heart chambers.1,2As a rule, an
ASD must be at least 10 mm in diameter to carry a significant left-to-right shunt, although most ASDs are not
circular, and maximum diameter may be difficult to
measure accurately.
Effort intolerance is the most common initial presenting
symptom in children. Atrial fibrillation or flutter is an
age-related reflection of atrial dilation and stretch that
seldom occurs at <40 years of age3.In ECG the rhythm
may be sinus, atrial fibrillation, or atrial flutter.First-degree heart block suggests a primum ASD 4 but
may be seen in older patients with a secundum ASD.QRS
axis is leftward or extremely to the right in ostium primum ASDs (OP ASDs). On chest X ray cardiomegaly
may be present from right heart dilation and occasionally
from left heart dilation if significant mitral regurgitation
is present in the patient with an ostium primum
ASD.5,6The central pulmonary arteries are characteristically enlarged, with pulmonary plethora indicating increased pulmonary flow.
Transthoracic echocardiography documents the type(s)
and size of the ASD(s), the direction(s) of the shunt, and,
in experienced hands, the presence of anomalous pulmonary venous return.In a patient with a primum ASD,
the left AV valve is trileaflet and almost always demonstrates some regurgitation. Patients with an isolated ostium primum ASD are typically referred for elective
repair between the ages of 2 and 5 years. Some patients
may reach adulthood without symptoms or ignoring the symptoms. In our study, children have
tolerated surgery well as a whole. Pulmonary hypertension and elevated pulmonary vascular resistance do not
appear to be contraindications and generally improve
postoperatively. Long-term follow-up is requisite.
atriotomy placed anteriorly, close to the atrioventricular
junction gives excellent exposure of the atrial septum and
both atrioventricular valves. The location of the coronary
sinus as a landmark for the adjacent AV node, and the
fossa ovalis with a potential secundum defect should be
noted. Saline instillation into the left ventricle closes the
mitral valve to allow an initial assessment of competency
and the anatomy of the components of the anterior leaflet.
The cleft closure is performed beginning at the base of the
cleft, nearest the ventricular septum. I prefer a technique
using horizontal mattress sutures of fine Prolene that keep
the edges of the leaflets rolled under, causing less distortion of the valve.
The distance between the points where the AV valve
tissue meets the AV annulus superiorly and inferiorly is
measured [FIGURE 1 ]. It is important to make the portion of the patch that attaches between these points
slightly smaller than this distance. This will create a slight
annuloplasty effect as well as prevent lateral tension on
the cleft closure. After cleft closure the competence of the
valve should be tested and annuloplasty stitches may be
added adjacent to one or both commissures, if needed.
Attachment of the autologous, gluterladehyde-fixed pericardial patch for closure of the septal defect is begun at
the mid-point of the valve, adjacent to the base of the
closed cleft. Tying down the first stitch allows superior or
inferior traction on this suture which facilitates identification of the right-left leaflet junction for attaching the
remainder of the base of the patch to the ventricular septal
crest. Inferiorly, as the patch is attached within the atrium
moving away from the valve, care must be taken to avoid
injury to the AV node and His bundle [FIGURE 2 ].
MATERIALS AND METHODS
Thirty patients (20 males, 10 females; mean age
32.4+/-11.1 years; range: 2 to 5 years) who had surgical
repair of OP-ASD between 2010 and 2015 were followed. All patients were examined physically and underwent chest radiography, ECG and echocardiography
(cross-sectional and Doppler) before and after surgery.
Cardiopulmonary support utilizing bicaval cannulation
and mild hypothermia is employed. A longitudinal right
Figure 1: Ostium Primum
Atrial Septal
Defect
with normal Tricuspid
and Mitral Valve [No
Anterior Mitral Valve Leaflet Cleft ]
An additional PFO or small secundum ASD is usually
closed separately using a primary suture technique, or
may be incorporated into the lateral attachment of the
pericardial patch.
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DISCUSSION
During fetal development, the rudimentary atrium is
divided by the septum primum, except for an anterior
and inferior space that is the ostium primum. The ostium
primum is sealed by fusion of the superior and inferior
endocardial cushions around 5 weeks' gestation. Failure
to do so results in an ostium primum ASD. The endocardial cushions also contribute to the complete formation of 2 separate AV valves and the inlet interventricular septum. For this reason, ostium primum ASDs commonly are associated with malformations of these structures.
Figure 2: Closed ostium primum atrial septal defect
with pericardial patch, associated
patent foramen
ovale also seen
Intraoperative transesophageal echocardiography is routinely used following weaning from bypass to assess the
repair. In our practice we plan for extubation in the operating room, observation overnight in the cardiac ICU,
and a typical inpatient stay of 3 to 4 days.Patients often
require inotropic support and/or afterload reduction in the
early postoperative period. Atrial pacing restores AV
synchrony and may be beneficial to reduce AV valve
insufficiency and increase cardiac output.
RESULT
Autologous pericardium was used to close the defect in
all patients. Mitral valvuloplasty (repair of the cleft) was
performed in 16patients, and De Vega annuloplasty in
five .The abnormal AV junction results in an “unwedged”
aorta and leads to a displacement of the AV conduction
tissue, which in turn produces the characteristic left-axis
deviation and predisposes these patients to heart
block.The most common associated anomalies are a secundum ASD and a persistent left SVC draining into the
coronary sinus. The occurrence of surgical complete
heart block in these patients has practically disappeared
in the modern era.11
There were no hospital deaths. In one case a pacemaker
was implanted five days after surgery because of complete heart block. Preoperatively, eighteen patients
(60%) were in NYHA classes III and IV; at the end of
follow up, 28 (93.3%) were in classes I and II. The
preoperative mean cardiac volume index of 660 +/- 208
ml/m(2) was reduced significantly after repair to 512 +/102 ml/m(2) (p < 0.05). Before surgery, mitral regurgitation was observed (severe in five cases, moderate in
fifteen, mild in ten). Postoperatively, a residual intracardiac shunt was identified in one case. Postoperative mitral regurgitation was noted in six patients (moderate in
two, mild in four). The right ventricular dimension was
decreased significantly, from 5.2 +/- 1.4 mm before surgery to 3.4 +/- 0.4 mm after repair (p < 0.001).
Ostium primum ASDs are most commonly seen with a
cleft in the anterior leaflet of the mitral valve, but they
may occur in isolation. This is sometimes termed a partial AV canal defect or a partial AV septal defect. In this
case, a 5-leaflet AV valve is arranged so that separate
right and left components (a tricuspid valve and a mitral
valve) are present. The leaflets connect to each other and
then adhere to the crest of the interventricular septum.
This results in shunting at the atrial level with no ventricular level shunting. Generally, a commissure is observed between the left superior and inferior bridging
leaflets because of abnormal fusion of the left tubercle
of the superior and inferior cushions, which results in a
cleft in the anterior leaflet of the mitral valve.
Pathophysiology: Shunting is predominantly left-to-right
in the absence of pulmonary vascular disease or significant right ventricular outflow tract obstruction. This results in volume overload of the right atrium and ventricle and pulmonary overcirculation. If the mitral valve
cleft causes significant mitral regurgitation, the left side
of the heart also becomes volume overloaded. A left
ventricle to right atrium shunt can be present, which
further overloads both the right and left heart.
Etiology: The most common cause of an ostium primum
ASD is genetic, associated with trisomy 21.
Well-described associations have been reported with
Holt-Oram syndrome, Noonan syndrome, and Ellis-van
Creveld syndrome, among others. In children with normal chromosomes, however, the cause remains unknown. Research into the molecular genetic basis for
AV canal and AV septal defects is ongoing. The
male-to-female ratio is 1:1.
Patients with smaller defects and little or no mitral regurgitation may present at any age with a murmur and/or
an abnormal ECG. Those with more severe mitral regurgitation typically present with CHF in the first 1-2 years
of life.
Prognosis: Pediatric patients with small left-to-right
shunts and no significant mitral regurgitation who have
not undergone surgery are at relatively low risk for
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complications. In these patients, adult survival is expected, but complications can develop as age advances.
Untreated patients with large shunts and/or significant
mitral regurgitation are at significant risk of morbidity
and mortality. Death, arrhythmia, heart block, refractory
heart failure, and advanced pulmonary vascular disease
are the most common complications and tend to increase
with advancing age. Pulmonary vascular obstructive
disease may develop in a subset of patients, with patients
with Down syndrome at highest risk. Prognosis is
guarded, and morbidity and mortality are high regardless
of therapy. Surgical repair generally improves life expectancy and alters the natural course of the disease.
Age and preoperative moderate-to-severe left AV valve
regurgitation were predictors of reoperation.
None declared.
REFERENCES
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CONCLUSION
Patients aged between 2 to 5 years with OP ASD will
benefit from surgical repair of the defect. Sizeable OP
ASDs with right heart dilation are associated with important age-related morbidity and mortality. Advanced
diagnostic modalities, earlier closure, and the advent of
catheter intervention (for OP ASDs) are all likely to improve long-term prospects for these patients. Current
evidence would suggest that all types of OPASDs with
right heart dilation should be considered for timely closure once the diagnosis is established, irrespective of age.
ACKNOWLEDGEMENTS
None.
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FUNDING
None.
COMPETING INTERESTS
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